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Sample records for stabilization pond treatment

  1. CONJUGATE TREATMENT OF LEACHATE FROM LANDFILL AND SEWAGE IN DOMESTIC STABILIZATION PONDS

    Directory of Open Access Journals (Sweden)

    Valderi Duarte Leite

    2016-01-01

    Full Text Available In Brazil, the per capita generation of municipal solid waste is approximately 0.80 kg hab-1 day-1, which implies daily production of 156 tons, whereas on average 50% of this quantity of waste is composed mainly of putrescible organic material that will contribute to the leachate generation process directly influencing the qualitative and quantitative aspects. Landfill leachate basically originates from the percolation process of different types of water and is considered a wastewater to cause in significant environmental impact on the environment, given in possession of high concentration of ammonia nitrogen, organic matter difficult to biodegradation, metals heavy and xenobiotics. The objective of this study was to evaluate the performance of a series of stabilization ponds, the treatment process conjugate of landfill leachate fresh more domestic sewage in the proportion of 1 plus 99% (volume percent, respectively. The experimental system consisted of four stabilization ponds in series, being a facultative pond, followed by three maturation ponds. . The applied surface charge (λs the series of stabilization ponds was 320 kg DBO5 ha-1 day-1 with hydraulic retention time (HRT of 17 days for the series. The average removal efficiency of BOD5 and ammonia was 69 and 86% respectively, while removing coliform efficiency always in the 99.9% threshold during the monitoring period was 220 days. Overall it can be concluded that treatment conjugate landfill leachate and sewage in stabilization ponds, in northeastern Brazil, is emerging as a promising technological alternative, given the comfortable area availability in northeastern Brazil, conditions climate favorable and the ponds system present low ratio cost / benefit when compared to other waste treatment systems of this nature.

  2. Wastewater stabilization ponds - an appropriate technology for sewage treatment and refuse

    International Nuclear Information System (INIS)

    Aziz, J.A.

    1999-01-01

    Treatment of wastewater is imperative to protect human health and environmental quality. To this effect, the chosen technology should be cost effective, simple and easy to operate and maintain. Wastewater stabilization ponds offer one such technology and their use should be promoted in countries with scarcity of water so as to reuse the treated effluents in irrigation. Long term, pilot scale investigations on the performance of wastewater stabilization ponds have been undertaken at the Institute of Environmental Engineering and Research, Lahore to develop design criteria for their local use. This paper discuss the types and operation of waste stabilization ponds and the extent of their application in Pakistan. The need for users' education for effective operation of this simple facility is also emphasized. (author)

  3. Rapid Sand Filtration for Best Practical Treatment of Domestic Wastewater Stabilization Pond Effluent

    Science.gov (United States)

    Boatright, D. T.; Lawrence, C. H.

    1977-01-01

    The technical and economic feasibility of constructing and operating a rapid sand filtration sewage treatment system as an adjunct to a waste water stabilization pond is investigated. The study concludes that such units are within the technical and economic constraints of a small community and comply with the EPA criteria. (BT)

  4. The Distribution of Microalgae in a Stabilization Pond System of a Domestic Wastewater Treatment Plant in a Tropical Environment (Case Study: Bojongsoang Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Herto Dwi Ariesyady

    2016-02-01

    Full Text Available The Bojongsoang Wastewater Treatment Plant (WWTP serves to treat domestic wastewater originating from Bandung City, West Java, Indonesia. An abundant amount of nutrients as a result of waste decomposition increases the number of microalgae populations present in the pond of the wastewater treatment plant, thereby causing a population explosion of microalgae, also called algal blooming. In a stabilization pond system, the presence of algal blooming is not desirable because it can decrease wastewater treatment performance. More knowledge about the relationship between the nutrients concentration and algae blooming conditions, such as microalgae diversity, is needed to control and maintain the performance of the wastewater treatment plant. Therefore this study was conducted, in order to reveal the diversity of microalgae in the stabilization pond system and its relationship with the water characteristics of the comprising ponds. The results showed that the water quality in the stabilization pond system of Bojongsoang WWTP supported rapid growth of microalgae, where most rapid microbial growth occurred in the anaerobic pond. The microalgae diversity in the stabilization ponds was very high, with various morphologies, probably affiliated with blue-green algae, green algae, cryptophytes, dinoflagellates and diatoms. This study has successfully produced information on microalgae diversity and abundance profiles in a stabilization pond system.

  5. Two-step upflow anaerobic sludge bed system for sewage treatment under subtropical conditions with posttreatment in waste stabilization ponds

    NARCIS (Netherlands)

    Seghezzo, L.; Trupiano, A.P.; Liberal, V.; Todd, P.G.; Figueroa, M.E.; Gutierrez, M.A.; Silva Wilches, Da A.C.; Iribarnegaray, M.; Guerra, R.G.; Arena, A.; Cuevas, C.M.; Zeeman, G.; Lettinga, G.

    2003-01-01

    A pilot-scale sewage treatment system consisting of two upflow anaerobic sludge bed (UASB) reactors followed by five waste stabilization ponds (WSPs) in series was studied under subtropical conditions. The first UASB reactor started up in only 1 mo (stable operation, high chemical oxygen demand

  6. Combined treatment of chemical, pharmaceutical and cosmetic industrial effluents by waste stabilization ponds.

    Science.gov (United States)

    Veeresh, Mangala; Veeresh, A V; Hosetti, B B

    2002-10-01

    Influent and final effluent was collected from the CMM Ltd., Bethora, Ponda, Goa and were analysed for pH, DO, BOD, enzyme activity and chlorophyll content of the waste stabilization pond for over a period of two years of which the data for one year (pre monsoon, monsoon and post monsoon periods) is given. The study revealed that the DO was maximum during the pre-monsoon months and least during the monsoon. Maximum removal of BOD and phosphate was observed during the pre-monsoon periods. Enzymatic activity was at its peak during the monsoons than during the other months. Chlorophyll content was maximum during the pre-monsoon months due to increased growth of phytoplankton as the conditions were favourable for their growth. Also depending on the concentration of different chlorophyll pigments, one can come to know the different groups of algae inhabiting the stabilization ponds.

  7. STRATIFICATION IN WASTE STABILIZATION PONDS II: MODELLING

    African Journals Online (AJOL)

    NIJOTECH

    The occurrence of thermal stratification in waste stabilization ponds (WSPs) alters the flow pattern of the pond. ... compared favourably with the experimental observation with coefficients of correlation ranging from .... is determined experimentally by sampling in the region of the pond inlet at various depths. Four models exist ...

  8. variation of some waste stabilization pond parameters with shape

    African Journals Online (AJOL)

    Waste Stabilization Pond (WSP) are designed to provide control environment for wastewater treatment. The primary purpose of wastewater treatment is the reduction of pathogenic contamination, suspended solids, oxygen demand and nutrient environment. The geometry of the pond could be structured in order to give the ...

  9. Variation of some Waste Stabilization Pond Parameters with Shape ...

    African Journals Online (AJOL)

    Waste Stabilization Pond (WSP) are designed to provide control environment for wastewater treatment. The primary purpose of wastewater treatment is the reduction of pathogenic contamination, suspended solids, oxygen demand and nutrient environment. The geometry of the pond could be structured in order to give the ...

  10. Performance evaluation of wastewater stabilization ponds in Yazd-Iran

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    Mahdi Farzadkia

    2014-11-01

    Full Text Available Background: Yazd waste stabilization pond facilities consist of three stabilization pond systems, module 1, module 2 and module 3 that AWSP module 1 has started its operation. The existing facilities have had several problems in their operation. The objectives of this research were to evaluate the performance of stabilization ponds in wastewater treatment of the city of Yazd, due to several problems in their operation, and to prepare a scheme of its upgrading, if necessary. Methods: During the period from December to June 2010, data analysis were carried out for both raw and treated wastewater. Results: Results of these investigations showed that the average effluent concentrations of Biochemical Oxygen Demand 5 (BOD5, Chemical Oxygen Demand (COD and Suspended Solid (SS taken from anaerobic pond and secondary facultative ponds of module 1 were 306.9, 135.18, 139.75 and 136.75, 69.025, 136.5 mg/L, respectively. Conclusion: These results indicated that the effluent of the anaerobic pond of module 1 was complied with the Iranian treated wastewater standards for agricultural reuse in terms of BOD5 and COD concentrations; hence the secondary facultative ponds could be changed to other primary facultative ponds in order to increase the capacity of wastewater treatment plant.

  11. Wastewater management in Khartoum Region Soba wastewater treatment plant (stabilization ponds)

    International Nuclear Information System (INIS)

    Maki, A. M. E.

    2010-03-01

    Soba wastewater treatment plant will be replaced shortly by new plant based on activate sludge. This study was carried in order to evaluate: the design, physical, chemical and biological characteristics and the capacity of the plant. Outlet Effluents quality was compared with Sudan wastewater treatment standards. Samples analyses were carried by UNESCO CHAIR 2006 (Khartoum State). It was found that the result is not as: The designed and standard level especially for BOD, COD, TBC and TC. It was also found that BOD and COD of the effluents were not complying with adopted standards for treated wastewater to be discharged to the environment. The study reached the conclusions that plant is overloaded and the characteristics of the wastewater received is not as the design which affects the efficiency of the treatment process. (Author)

  12. Performance Of The Akosombo Waste Stabilization Ponds In Ghana ...

    African Journals Online (AJOL)

    A study was conducted to determine the treatment performance of the Akosombo waste stabilization ponds and the effect of seasonal changes on the final effluent quality. The waste water quality parameters ... Une étude était entreprise pour déterminer le résultat de traitement de bassins de stabilisation du déchet d' ...

  13. Removal of Algae in Stabilization Ponds Effluent using Moringa ...

    African Journals Online (AJOL)

    A number of studies have proved natural coagulants achieve high turbidity removal in water treatment. A pilot scale study was conducted to evaluate the effectiveness of natural coagulant (moringa oleifera) with respect to algae removal. Required effluent from stabilization ponds was diverted into the horizontal baffle ...

  14. Nitrogen mass balance in waste stabilization ponds at the University ...

    African Journals Online (AJOL)

    ... the dominant nitrogen transformation mechanisms, while in secondary facultative pond F3 and maturation pond M, ammonia uptake was the dominant transformation route. The results obtained in this work may be used as a management tool in assessing the levels of nitrogen compounds in waste stabilization ponds and ...

  15. The algae of Gaborone wastewater stabilization ponds: Implications ...

    African Journals Online (AJOL)

    The types of algae found in the wastewater stabilization ponds in Gaborone were studied. Being the base of the food chain in any aquatic habitat, algae contribute significantly to the functioning and value of the ponds. The (liversit)' and abundance of the algae in the two pond systems at Broadhurst and Phakalane were ...

  16. Modeling Nitrogen Decrease in Water Lettuce Ponds from Waste Stabilization Ponds

    Science.gov (United States)

    Putri, Gitta Agnes; Sunarsih

    2018-02-01

    This paper presents about the dynamic modeling of the Water Lettuce ponds as a form of improvement from the Water Hyacinth ponds. The purpose of this paper is to predict nitrogen decrease and nitrogen transformation in Water Lettuce ponds integrated with Waste Stabilization Ponds. The model consists of 4 mass balances, namely Dissolved Organic Nitrogen (DON), Particulate Organic Nitrogen (PON), ammonium (NH4+), Nitrate and Nitrite (NOx). The process of nitrogen transformation which considered in a Water Lettuce ponds, namely hydrolysis, mineralization, nitrification, denitrification, plant and bacterial uptake processes. Numerical simulations are performed by giving the values of parameters and the initial values of nitrogen compounds based on a review of previous studies. Numerical results show that the rate of change in the concentration of nitrogen compounds in the integration ponds of waste stabilization and water lettuce decreases and reaches stable at different times.

  17. Design of waste stabilization pond systems: A review.

    Science.gov (United States)

    Ho, Long T; Van Echelpoel, Wout; Goethals, Peter L M

    2017-10-15

    A better design instruction for waste stabilization ponds is needed due to their growing application for wastewater purification, increasingly strict environmental regulations, and the fact that most of previous design manuals are outdated. To critically review model-based designs of typical pond treatment systems, this paper analyzed more than 150 articles, books, and reports from 1956 to 2016. The models developed in these publications ranged from simple rules and equations to more complex first-order and mechanistic models. From a case study on all four approaches, it appeared that rules of thumb is no longer a proper tool for pond designs due to its low design specification and very high output variability and uncertainty. On the other hand, at the beginning phase of design process or in case of low pressure over land and moderate water quality required, regression equations can be useful to form an idea for pond dimensions. More importantly, mechanistic models proved their capacity of generating more precise and comprehensive designs but still need to overcome their lack of calibration and validation, and overparameterization. In another case study, an essential but often overlooked role of uncertainty analysis in pond designs was investigated via a comparison between deterministic and uncertainty-based approaches. Unlike applying a safety factor representing all uncertainty sources, probabilistic designs quantify the uncertainty of model outputs by including prior uncertainty of inputs and parameters, which generates more scientifically reliable outcomes for decision makers. Based on these findings, we advise engineers and designers to shift from the conventional approaches to more innovative and economic tools which are suitable for dealing with large variations of natural biological systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Performance comparison and economics analysis of waste stabilization ponds and horizontal subsurface flow constructed wetlands treating domestic wastewater: a case study of the Juja sewage treatment works.

    Science.gov (United States)

    Mburu, Njenga; Tebitendwa, Sylvie M; van Bruggen, Johan J A; Rousseau, Diederik P L; Lens, Piet N L

    2013-10-15

    The performance, effluent quality, land area requirement, investment and operation costs of a full-scale waste stabilization pond (WSP) and a pilot scale horizontal subsurface flow constructed wetland (HSSF-CW) at Jomo Kenyatta University of Agriculture and Technology (JKUAT) were investigated between November 2010 to January 2011. Both systems gave comparable medium to high levels of organic matter and suspended solids removal. However, the WSP showed a better removal for Total Phosphorus (TP) and Ammonium (NH4(+)-N). Based on the population equivalent calculations, the land area requirement per person equivalent of the WSP system was 3 times the area that would be required for the HSSF-CW to treat the same amount of wastewater. The total annual cost estimates consisting of capital, operation and maintenance (O&M) costs were comparable for both systems. However, the evaluation of the capital cost of either system showed that it is largely influenced by the size of the population served, local cost of land and the construction materials involved. Hence, one can select either system in terms of treatment efficiency. When land is available other factor including the volume of wastewater or the investment, and O&M costs determine the technology selection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. STRATIFICATION IN WASTE STABILIZATION PONDS I: EFFECTS ...

    African Journals Online (AJOL)

    NIJOTECH

    within the pond. Hence thermal stratification resulted in the variation of BOD values within the vertical water column with the maximum value of 1149.5mg/l at the bottom and a mini mum value of 450mg/l at the surface layers as shown in Figures 3c, 3d and 5 to 10. Chemical Oxygen Demand (COD). The vertical distribution of ...

  20. Integrated Application of the UASB Reactor and Ponds for Domestic Sewage Treatment in Tropical Regions

    NARCIS (Netherlands)

    Cavalcanti, P.F.F.

    2003-01-01

    Waste stabilization ponds are widely applied for domestic sewage treatment in Brazil. The main objective of conventional waste stabilisation ponds (WSP's) is, nomen est omen , to remove the organic material from wastewater. To achieve this objective, a quite long liquid retention time (

  1. variation of some waste stabilization pond parameters with shape

    African Journals Online (AJOL)

    θ θi then σ2 = 2d – 2d2 (1 – e-1/d). - - - - - - - - - - - - - - - - - - - - - - - - - -. (5) the term, d, can be calculated by trial and error where θi. = time after impulse injection, days; and. Ci. = tracer response concentration at the exist stream, mg/l. VARIATION OF SOME WASTE STABILIZATION POND PARAMETERS WITH SHAPE. 111 ...

  2. Birds of the sewage stabilization ponds at Obafemi Awolowo ...

    African Journals Online (AJOL)

    A qualitative study of aquatic macroinvertebrates and birds associated with sewage stabilization ponds was carried out on the campus of Obafemi Awolowo University, Ile-Ife, Nigeria. Thirteen macroinvertebrate species were recorded out of which Ephemeroptera, Chironomus larvae, mosquito larvae and pupae and ...

  3. Waste Stabilization Pond Design For University Of Ilorin

    Directory of Open Access Journals (Sweden)

    Raji

    2017-06-01

    Full Text Available This present study includes the use of MATLAB R2012b software for the design and analysis of waste stabilization pond for the university of Ilorin. Kwara State. Contamination and pollution resulting from unlawful and increasing wastewater discharge expose the environment to degradation and the populace to health risks. The forecasted population in 25years time was found to be 93606 people. The total volume of wastewater that will be generated in 2042 was found to be 9372.6m3day and the maturation pond had the largest area 43738.80m2 with its dimension being 296m by 148m by 1.5m while the facultative pond had the least area 11715.75m2 with dimensions 501m by 167m by 1.5m.

  4. Performance of municipal waste stabilization ponds in the Canadian Arctic

    DEFF Research Database (Denmark)

    Ragush, Colin M.; Schmidt, Jordan J.; Krkosek, Wendy H.

    2015-01-01

    ), and ammonia-nitrogen were measured during the summer treatment period (late June until early September) from 2011 to 2014 in the WSP systems of four Nunavut communities; Pond Inlet, Clyde River, Grise Fiord and Kugaaruk. Monitoring results showed that WSPs in their current single cell design can achieve...

  5. Facultative Stabilization Pond: Measuring Biological Oxygen Demand using Mathematical Approaches

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    Wira S Ihsan

    2018-01-01

    Full Text Available Pollution is a man-made phenomenon. Some pollutants which discharged directly to the environment could create serious pollution problems. Untreated wastewater will cause contamination and even pollution on the water body. Biological Oxygen Demand (BOD is the amount of oxygen required for the oxidation by bacteria. The higher the BOD concentration, the greater the organic matter would be. The purpose of this study was to predict the value of BOD contained in wastewater. Mathematical modeling methods were chosen in this study to depict and predict the BOD values contained in facultative wastewater stabilization ponds. Measurements of sampling data were carried out to validate the model. The results of this study indicated that a mathematical approach can be applied to predict the BOD contained in the facultative wastewater stabilization ponds. The model was validated using Absolute Means Error with 10% tolerance limit, and AME for model was 7.38% (< 10%, so the model is valid. Furthermore, a mathematical approach can also be applied to illustrate and predict the contents of wastewater.

  6. Facultative Stabilization Pond: Measuring Biological Oxygen Demand using Mathematical Approaches

    Science.gov (United States)

    Wira S, Ihsan; Sunarsih, Sunarsih

    2018-02-01

    Pollution is a man-made phenomenon. Some pollutants which discharged directly to the environment could create serious pollution problems. Untreated wastewater will cause contamination and even pollution on the water body. Biological Oxygen Demand (BOD) is the amount of oxygen required for the oxidation by bacteria. The higher the BOD concentration, the greater the organic matter would be. The purpose of this study was to predict the value of BOD contained in wastewater. Mathematical modeling methods were chosen in this study to depict and predict the BOD values contained in facultative wastewater stabilization ponds. Measurements of sampling data were carried out to validate the model. The results of this study indicated that a mathematical approach can be applied to predict the BOD contained in the facultative wastewater stabilization ponds. The model was validated using Absolute Means Error with 10% tolerance limit, and AME for model was 7.38% (< 10%), so the model is valid. Furthermore, a mathematical approach can also be applied to illustrate and predict the contents of wastewater.

  7. Removal Efficiency of Linear Alkyl Benzene Sulfonate (LAS in Yazd Stabilization Pond

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    Asghar Ebrahimi

    2011-01-01

    Full Text Available Surfactants are organic chemicals with wide applications as detergents. Linear alkyl benzene sulfonate (LAS is an anionic surfactant most commonly used. Discharge of raw or treated wastewater containing this chemical into the environment causes major public health problems. In this study, 64 samples were taken from the effluent of Yazd Wastewater  Treatment Plant over a period of one year. The samples were analyzed according to standard methods. The results obtained from the samples taken in different seasons showed that the highest efficiency of anionic surfactant removal was achieved in the summer in the secondary facultative stabilization pond. The least efficiency was observed in the autumn in samples from the anaerobic stabilization pond. It was also found that treated wastewater discharged into surface waters, reused for agricultural irrigation, or discharged into absorbent wells had significant differences with Pvalue

  8. Importance of waste stabilization ponds and wastewater irrigation in the generation of vector mosquitoes in Pakistan

    DEFF Research Database (Denmark)

    Mukhtar, Muhammad; Ensink, Jeroen; Van der Hoek, Wim

    2006-01-01

    The objective of the current study was to investigate the role of waste stabilization ponds (WSP) and wastewater-irrigated sites for the production of mosquitoes of medical importance. Mosquito larvae were collected fortnightly from July 2001 to June 2002 in Faisalabad, Pakistan. In total, 3...... an overwhelming preference for anaerobic ponds, which receive untreated wastewater. Facultative ponds generated lower numbers of both Anopheles and Culex mosquitoes, whereas the last ponds in the series, the maturation ponds, were the least productive for both mosquito genera. An. subpictus and Anopheles...

  9. Stabilization of mixed waste - Rocky Flats solar ponds

    International Nuclear Information System (INIS)

    Bittner, T.A.; Mathew, S.A.; Henderson, W.C.

    1993-01-01

    Among the wastes that require disposal as part of the Department of Energy's (DOE's) Environmental Restoration Program are large amounts of contaminated sludge and inorganic wastes. Halliburton NUS Corporation was awarded a contract by EG ampersand G Rocky Flats in March 1991 to stabilize mixed waste sludge contained in five solar evaporator ponds and to reprocess billets of solidified waste called Pondcrete and Saltcrete at DOE's Rocky Flats Plant. The scope of the project consists of waste characterization and treatability studies for process development, followed by design, construction and operation of various process trains to remediate different waste forms ranging from solid Pondcrete/Saltcrete blocks to aqueous brine solutions. One of the significant advances made was the development of a durable and certifiable stabilization formulation capable of treating concentrated nitrate solution wastes. The project uses high-volume grout mixing and pumping technologies with process control techniques that accommodate the heterogeneity of the wastes. To comply with all relevant environmental regulations and to provide a safe working atmosphere for plant personnel, Halliburton NUS designed process trains such that all emissions were eliminated during the remediation process. Personnel protection equipment requirements have been downgraded due to safeguards incorporated in the design. The technical and regulatory issues that were encountered would be typical of stabilization efforts underway at other DOE sites. Thus the lessons learned and concepts developed can be expected to have widespread application

  10. Emissions from Produced Water Treatment Ponds, Uintah Basin, Utah, USA

    Science.gov (United States)

    Mansfield, M. L.; Lyman, S. N.; Tran, H.; O'Neil, T.; Anderson, R.

    2015-12-01

    An aqueous phase, known as "produced water," usually accompanies the hydrocarbon fluid phases that are extracted from Earth's crust during oil and natural gas extraction. Produced water contains dissolved and suspended organics and other contaminants and hence cannot be discharged directly into the hydrosphere. One common disposal method is to discharge produced water into open-pit evaporation ponds. Spent hydraulic fracturing fluids are also often discharged into the same ponds. It is obvious to anyone with a healthy olfactory system that such ponds emit volatile organics to the atmosphere, but very little work has been done to characterize such emissions. Because oil, gas, and water phases are often in contact in geologic formations, we can expect that more highly soluble compounds (e.g., salts, alcohols, carbonyls, carboxyls, BTEX, etc.) partition preferentially into produced water. However, as the water in the ponds age, many physical, chemical, and biological processes alter the composition of the water, and therefore the composition and strength of volatile organic emissions. For example, some ponds are aerated to hasten evaporation, which also promotes oxidation of organics dissolved in the water. Some ponds are treated with microbes to promote bio-oxidation. In other words, emissions from ponds are expected to be a complex function of the composition of the water as it first enters the pond, and also of the age of the water and of its treatment history. We have conducted many measurements of emissions from produced water ponds in the Uintah Basin of eastern Utah, both by flux chamber and by evacuated canister sampling with inverse modeling. These measurements include fluxes of CO2, CH4, methanol, and many other volatile organic gases. We have also measured chemical compositions and microbial content of water in the ponds. Results of these measurements will be reported.

  11. Mathematical Analysis for the Optimization of Wastewater Treatment Systems in Facultative Pond Indicator Organic Matter

    Science.gov (United States)

    Sunarsih; Widowati; Kartono; Sutrisno

    2018-02-01

    Stabilization ponds are easy to operate and their maintenance is simple. Treatment is carried out naturally and they are recommended in developing countries. The main disadvantage of these systems is large land area they occupy. The aim of this study was to perform an optimization of the wastewater treatment systems in a facultative pond, considering a mathematical analysis of the methodology to determine the model constrains organic matter. Matlab optimization toolbox was used for non linear programming. A facultative pond with the method was designed and then the optimization system was applied. The analyse meet the treated water quality requirements for the discharge to the water bodies. The results show a reduction of hydraulic retention time by 4.83 days, and the efficiency of of wastewater treatment of 84.16 percent.

  12. Sulfur bacteria in wastewater stabilization ponds periodically affected by the ‘red-water’ phenomenon

    NARCIS (Netherlands)

    Belila, A.; Abbas, B.; Fazaa, I.; Saidi, N.; Snoussi, M.; Hassen, A.; Muyzer, G.

    2012-01-01

    Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the ‘red-water’ phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El

  13. Sulfur bacteria in wastewater stabilization ponds periodically affected by the 'red-water' phenomenon

    NARCIS (Netherlands)

    Belila, A.; Abbas, B.; Fazaa, I.; Saidi, N.; Snoussi, M.; Hassen, A.; Muyzer, G.

    2013-01-01

    Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the ‘red-water’ phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El

  14. On the Polymer Thickener for Viscosity-Stabilized Solar Pond

    Science.gov (United States)

    Matsumoto, Toshiro; Kato, Nobuhiro; Taga, Masao

    1998-09-01

    The optimal physical properties of an ionized polyacrylamide solution, selected as the most suitable thickener for the insulating layer of aviscosity-stabilized solar pond, are described. Light transmittance,viscosity and viscosity degradation were obtained for a range ofthicknesses from 1 cm to 15 cm (1 15 cm), weight concentrations of0.1 0.5% (0.1 0.5 wt%) and temperatures of the polymer of 20 80°C. Onset of convection was also measured for a given thickness of the polymersolution. An exposure test was carried out to prevent degradation of thepolymer using an antioxidant. It was confirmed that the viscosity was notdecreased and, on the contrary, increased slightly after 100 days. It wasshown experimentally that the critical Rayleigh number coincided with the theoretical values reported by Tien et al.. [Int. J. Heat MassTransf. 12 (1969) 1173]. Transmittances of the polymeric gel for the case ofvessels greater than 5 cm in thicknesses were better than those of theSPR402 solution (0.5 wt%).

  15. EFFECTIVENESS OF WASTE STABILIZATION PONDS IN REMOVAL OF LINEAR ALKYL BENZENE SALFONATE (LAS

    Directory of Open Access Journals (Sweden)

    Ahmed. M. Abdel-Rahman

    2013-01-01

    Full Text Available Detergents contain synthetic or organic surface active agents called surfactants, which are derived from petroleum product precursors. They have the common property of lowering the surface tensions of water thus allowing dirt or grease adhered to various articles to be washed off. Linear alkyl benzene sulfonate (LAS is a most commonly used anionic surfactant. Discharge of raw or treated wastewater containing this chemical substance into the environment causes major public health and enviromental problems. In this study, samples were taken from raw wastewater and effluents of treatment ponds of Elzaraby waste stabilization ponds over a period of one year. The treated effluent is either discharged into surface waters or re-used in agricultural irrigation. The samples were analyzed according to the standard methods. The results obtained from the samples taken in different seasons showed that the highest overall removal efficiency of LAS was achieved in summer season (77%, and the least efficiency was observed in Winter season (55%, while the maximum overall efficiency of BOD5 was in summer (88% and minimum efficiency was (73% in winter season. The Dissolved oxygen concentrations along the pond series (DO ranged from 0.18 to 4.8 mg/l.

  16. EFFECTIVENESS OF WASTE STABILIZATION PONDS IN REMOVAL OF LINEAR ALKYL BENZENE SALFONATE (LAS

    Directory of Open Access Journals (Sweden)

    Ahmed. M. Abdel-Rahman

    2013-06-01

    Full Text Available Detergents contain synthetic or organic surface active agents called surfactants, which are derived from petroleum product precursors. They have the common property of lowering the surface tensions of water thus allowing dirt or grease adhered to various articles to be washed off. Linear alkyl benzene sulfonate (LAS is a most commonly used anionic surfactant. Discharge of raw or treated wastewater containing this chemical substance into the environment causes major public health and enviromental problems. In this study, samples were taken from raw wastewater and effluents of treatment ponds of Elzaraby waste stabilization ponds over a period of one year. The treated effluent is either discharged into surface waters or re-used in agricultural irrigation. The samples were analyzed according to the standard methods. The results obtained from the samples taken in different seasons showed that the highest overall removal efficiency of LAS was achieved in summer season (77%, and the least efficiency was observed in Winter season (55%, while the maximum overall efficiency of BOD5 was in summer (88% and minimum efficiency was (73% in winter season. The Dissolved oxygen concentrations along the pond series (DO ranged from 0.18 to 4.8 mg/l.

  17. Disinfection of stabilization pond effluent by peracetic acid and sodium hypochlorite

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    Negar Rezania

    2013-01-01

    Conclusions: The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

  18. Rice field for the treatment of pond aquaculture effluents | Wang ...

    African Journals Online (AJOL)

    We conducted an experiment to evaluate the efficiency of rice fields in treating pond aquaculture effluent and its responses to different fertilizer treatments. Four treatments was considered in the experiment: no rice planted as the control (CT); rice planted and no fertilizer input (RE); rice planted and a rate of approximately ...

  19. EVALUATING THE ECOLOGICAL RESILIENT DRIVEN PERFORMANCE OF A TROPICAL WASTE STABILIZATION POND SYSTEM USING ECOLOGICAL SIGNATURE OF BIOLOGICAL INTEGRITY

    Directory of Open Access Journals (Sweden)

    Susmita Lahiri Ganguly

    2015-06-01

    Full Text Available Using ecological signature of biological integrity as a measure of performance, the reclamation efficiency of waste stabilization ponds was evaluated over a period of four years in a tropical sewage treatment plant – cum fish culture consisting of two anaerobic, two facultative and four maturation ponds located serially across the sewage effluent gradient. The four maturation ponds were used for batch culture of fish. Samples of surface and bottom water as well as surface sediment were collected twice a month from different ponds of the system and examined for some nutrient cycling bacteria, primary production, chlorophyll content of micro-algae, phytoplankton, zooplankton abundance, fish growth and water quality parameters. Computation of ecological signature using aerobic mineralization index for heterotrophic and ammonifying bacteria revealed steady increase across the sewage effluent gradient. The heterotrophic and ammonifying bacterial populations appeared to have a direct function with the concentrations of chemical oxygen demand of water. The sum of total scores for different optimal conditions for fish growth increased as a function of the distance from the source of effluent implying that ecological resilience of the waste stabilization ponds has been accomplished by the sedimentation, chelation, and biological functional attributes mediated through redundancy of different subsystems, self- purification capacity of the system as a whole.

  20. A Closer Look on Spatiotemporal Variations of Dissolved Oxygen in Waste Stabilization Ponds Using Mixed Models

    Directory of Open Access Journals (Sweden)

    Long Ho

    2018-02-01

    Full Text Available Dissolved oxygen is an essential controlling factor in the performance of facultative and maturation ponds since both take many advantages of algal photosynthetic oxygenation. The rate of this photosynthesis strongly depends on the time during the day and the location in a pond system, whose roles have been overlooked in previous guidelines of pond operation and maintenance (O&M. To elucidate these influences, a linear mixed effect model (LMM was built on the data collected from three intensive sampling campaigns in a waste stabilization pond in Cuenca, Ecuador. Within two parallel lines of facultative and maturation ponds, nine locations were sampled at two depths in each pond. In general, the output of the mixed model indicated high spatial autocorrelations of data and wide spatiotemporal variations of the oxygen level among and within the ponds. Particularly, different ponds showed different patterns of oxygen dynamics, which were associated with many factors including flow behavior, sludge accumulation, algal distribution, influent fluctuation, and pond function. Moreover, a substantial temporal change in the oxygen level between day and night, from zero to above 20 mg O2·L−1, was observed. Algal photosynthetic activity appeared to be the main reason for these variations in the model, as it was facilitated by intensive solar radiation at high altitude. Since these diurnal and spatial patterns can supply a large amount of useful information on pond performance, insightful recommendations on dissolved oxygen (DO monitoring and regulations were delivered. More importantly, as a mixed model showed high predictive performance, i.e., high goodness-of-fit (R2 of 0.94, low values of mean absolute error, we recommended this advanced statistical technique as an effective tool for dealing with high autocorrelation of data in pond systems.

  1. CFD analysis of sludge accumulation and hydraulic performance of a waste stabilization pond.

    Science.gov (United States)

    Alvarado, Andres; Sanchez, Esteban; Durazno, Galo; Vesvikar, Mehul; Nopens, Ingmar

    2012-01-01

    Sludge management in waste stabilization ponds (WSPs) is essential for safeguarding the system performance. Sludge accumulation patterns in WSPs are strongly influenced by the pond hydrodynamics. CFD modeling was applied to study the relation between velocity profiles and sludge deposition during 10 years of operation of the Ucubamba WSP in Cuenca (Ecuador). One tracer experiment was performed and three sludge accumulation scenarios based on bathymetric surveys were simulated. A residence time distribution (RTD) analysis illustrated the decrease of residence times due to sludge deposition. Sludge accumulation rates were calculated. The influence of flow pattern on the sludge deposition was studied, enabling better planning of future pond operation and desludging.

  2. Dewatering to stabilize fly ash disposal ponds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Delaney, B.T.; Cluen, G.J.; Floess, C.

    1985-05-01

    The required removal of an inactive fly ash pond at the Seward Generating Station posed three related problems to Pennsylvania Electric Company. The saturated, unstable fly ash was difficult to excavate, to transport and to place on the disposal pile at slopes steep enough to be contained within the limited available storage area. This report describes: the performance of a limited field testing using a vacuum wellpoint dewatering system; the extrapolation of the test data into an overall dewatering scheme; the testing and monitoring performed on the fly ash and dewatering system during ash removal; and the recommended procedures to be used for applying the methods described to other fly ash ponds. The wellpoint system utilized at this site was capable of improving the condition of the fly ash to the extent that excavation of the ash could easily be performed with a tire mounted front end loader operating from the natural clay bottom of the pond. Of the initial twelve-foot average thickness of ash, the residual unstable material after dewatering was less than one foot thick. Hauling and disposal problems were also improved since the ash would no longer flow when being bumped. 21 refs., 56 figs., 9 tabs.

  3. Shrimp pond wastewater treatment using pyrolyzed chicken feather as adsorbent

    Science.gov (United States)

    Moon, Wei Chek; Jbara, Mohamad Hasan; Palaniandy, Puganeshwary; Yusoff, Mohd Suffian

    2017-10-01

    In this study, chicken feather fiber was used as a raw material to prepare a non-expensive adsorbent by pyrolysis without chemical activation. The main pollutants treated in this study were chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N) from shrimp pond wastewater containing high concentrations of nutrients, which caused the eutrophication phenomenon in adjacent water. Batch adsorption studies were performed to investigate the effect of pH (5-8), mass of adsorbent (0.5-3 g), and shaking time (0.5-2 h) on the removal efficiency of COD and NH3- N. Experimental results showed that the optimum conditions were as follows: pH 5, 0.5 g of adsorbent, and 0.5 h of shaking. Under these conditions, 34.01% and 40.47% of COD and NH3-N were removed, respectively, from shrimp pond wastewater. The adsorption processes were best described by the Langmuir isotherm model for COD and NH3-N removal, with maximum monolayer adsorption capacity of 36.9 and 7.24 mg/g for COD and NH3-N, respectively. The results proved that chicken feather could remove COD and NH3-N from shrimp pond wastewater. However, further studies on thermal treatment should be carried out to increase the removal efficiency of pyrolyzed chicken feather fiber.

  4. Removal of Chromium and Cadmium from Wastewater in Waste Stabilization Ponds, Yazd-Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Samaei

    2016-04-01

    Full Text Available Background: Heavy metals have destructive and irreversible effects on the human, plants and animals. Some industries in Yazd enter industrial wastewater to municipal wastewater collection system. This can lead to high levels of heavy metals in wastewater and in turn in the wastewater treatment plant effluent. Methods: This study was carried out during four months from December 22, 2009 to May 20, 2010. The experiment was performed on the inflow, outlet of anaerobic pond and first and second facultative ponds of wastewater treatment plant and then transferred to the laboratory and measured by atomic absorption spectroscopy. Results: The results of the experiments showed that the average cadmium concentrations in the inflow, anaerobic pond outlet, and first and second facultative pond outlet were 0.0066, 0.0087, 0.0076, and 0.0083μg/l, respectively. The average amounts of chromium in the inflow, anaerobic pond outlet, and first and second facultative pond outlet were 0.0076, 0.0065, 0.0043, and 0.0056 μg/l, respectively. Cadmium concentration in the effluent was higher than standard. Conclusion: The comparison of the obtained data with Iranian standards for wastewater treatment for reuse in irrigation shows that the cadmium concentration exceeded the standard and the chromium concentration was lower than the standard. Therefore, it is not suitable for reuse in the crop farms and aquatic life

  5. BIOCIDE TREATMENT OF PONDS IN SCOTLAND TO ERADICATE SIGNAL CRAYFISH

    Directory of Open Access Journals (Sweden)

    PEAY S.

    2006-01-01

    Full Text Available This trial aimed to eradicate illegally introduced signal crayfish Pacifastacus leniusculus in the North Esk catchment, Scotland. Sites treated were (1 an isolated gravel-pit (c. 9,000 m3, with crayfish present for 6 years; (2 three dammed ponds, (c. 5,000 m3 and (3 a leaking, offline pond (c. 6,000 m3, with crayfish for two years. Preliminary toxicity tests with substrate present indicated doses. Treatment at sites (1 and (2 (in October 2004, water temperature 13°C comprised deoxygenation with sodium sulphite to stimulate emergence, then application of natural pyrethrum (Pyblast. Exposed margins were sprayed with Pyblast to prevent escapes. Crayfish mortality was high, but one survivor was seen after 5 days. Pyblast was applied from a tank with Na2SO3 residue, which subsequent investigation indicated reduced Pyblast below the target 0.1 mg l-1. Site (1 was re-treated (end October, target 0.15 mg l-1 Pyblast, no Na2SO3, 9°C. Mortality was confirmed using caged crayfish. Prior to treatment at site (2, throughflow was stopped and fish removed. Biomonitoring was carried out with freshwater shrimps Gammarus in the adjacent watercourse. Treatment of site (3 (December, target 0.2 mg l-1, 4°C necessitated continuous back-pumping of leakage for a 2-week recovery period to avoid contamination of the river downstream. Caged crayfish took up to 5 days for 100% mortality. No crayfish were found in a summer survey after the treatments with Pyblast alone, but were caught in the ponds with Na2SO3 pre-treatment. Monitoring is required for 2-5 years.

  6. Nile tilapia culture on domestic effluent treated in stabilization ponds.

    Directory of Open Access Journals (Sweden)

    Clovis Matheus Pereira

    2009-03-01

    Full Text Available The performance and filet quality of tilapias (Oreochromis niloticus culture in effluent stabilization lagoons was tested at the densities of 3 fish/m2 (T3, 7 fish/m2 (T2 and 7 fish/m2 in clean water + diet (T1 with 3 repetitions in tanks of 2.57m2 and 0.60m of water column with supplemental aeration. Fish culture in clean water plus diet (T1 presented the highest growth. The higher density T3 (7/m2 compared to T2 (3/m2 did not result in any difference of total production (p > 0.05 but this was compensated by the increased individual fish growth rate at lower density. The conditions that sustain fish survival culture with ETE effluent were attested by the high survival (> 90% under both treatments, but only 10% of the water samples from T2 and T3 N-total ammonium was favorable for fish growth (< 2.0mg/L. The rearing system improved the effluent quality, reducing the total organic nitrogen and the solids in suspension. The faecal coliforms, Salmonella sp. and Staphylococcus aureus from the effluent and fish were verified to be within the standards laid down by the World Health Organization (WHO.

  7. Increased pond depth improves algal productivity and nutrient removal in wastewater treatment high rate algal ponds.

    Science.gov (United States)

    Sutherland, Donna L; Turnbull, Matthew H; Craggs, Rupert J

    2014-04-15

    Depth has been widely recognised as a crucial operational feature of a high rate algal pond (HRAP) as it modifies the amount of light and frequency at which microalgal cells are exposed to optimal light. To date, there has been little focus on the optimisation of microalgal performance in wastewater treatment HRAPs with respect to depth, with advice ranging from as shallow as possible to 100 cm deep. This paper investigates the seasonal performance of microalgae in wastewater treatment HRAPs operated at three different depths (200, 300 and 400 mm). Microalgal performance was measured in terms of biomass production and areal productivity, nutrient removal efficiency and photosynthetic performance. The overall areal productivity significantly increased with increasing depth. Areal productivity ranged from 134 to 200% higher in the 400 mm deep HRAP compared to the 200 mm deep HRAP. Microalgae in the 400 mm deep HRAP were more efficient at NH4-N uptake and were photosynthetically more efficient compared to microalgae in the 200 mm deep HRAP. A higher chlorophyll-a concentration in the 200 mm deep HRAP resulted in a decrease in photosynthetic performance, due to insufficient carbon supply, over the course of the day in summer (as indicated by lower α, Pmax and oxygen production) compared to the 300 and 400 mm deep HRAPs. Based on these results, improved areal productivity and more wastewater can be treated per land area in the 400 mm deep HRAPs compared to 200 mm deep HRAPs without compromising wastewater treatment quality, while lowering capital and operational costs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Evaluating the performance of a retrofitted stormwater wet pond for treatment of urban runoff.

    Science.gov (United States)

    Schwartz, Daniel; Sample, David J; Grizzard, Thomas J

    2017-06-01

    This paper describes the performance of a retrofitted stormwater retention pond (Ashby Pond) in Northern Virginia, USA. Retrofitting is a common practice which involves modifying existing structures and/or urban landscapes to improve water quality treatment, often compromising standards to meet budgetary and site constraints. Ashby Pond is located in a highly developed headwater watershed of the Potomac River and the Chesapeake Bay. A total maximum daily load (TMDL) was imposed on the Bay watershed by the US Environmental Protection Agency in 2010 due to excessive sediment and nutrient loadings leading to eutrophication of the estuary. As a result of the TMDL, reducing nutrient and sediment discharged loads has become the key objective of many stormwater programs in the Bay watershed. The Ashby Pond retrofit project included dredging of accumulated sediment to increase storage, construction of an outlet structure to control flows, and repairs to the dam. Due to space limitations, pond volume was less than ideal. Despite this shortcoming, Ashby Pond provided statistically significant reductions of phosphorus, nitrogen, and suspended sediments. Compared to the treatment credited to retention ponds built to current state standards, the retrofitted pond provided less phosphorus but more nitrogen reduction. Retrofitting the existing stock of ponds in a watershed to at least partially meet current design standards could be a straightforward way for communities to attain downstream water quality goals, as these improvements represent reductions in baseline loads, whereas new ponds in new urban developments simply limit future load increases or maintain the status quo.

  9. Removal of 226Ra from tailings pond effluents and stabilization of uranium mine tailings. Bench and pilot scale studies

    International Nuclear Information System (INIS)

    Schmidtke, N.W.; Averill, D.; Bryant, D.N.; Wilkinson, P.; Schmidt, J.W.

    1978-01-01

    Increased world demand for uranium has resulted in recent expansion of Canadian uranium mining operations. Problems have been identified with the discharge of radionuclides such as 226 Ra from tailings pond effluents and with the stabilization of mine tailings. At Environment Canada's Wastewater Technology Centre (WTC) two projects were undertaken in cooperation with the Canadian Uranium Mining Industry and other federal government agencies to address these problems. The first project reports on the progress of bench and pilot scale process simulations for the development of a data base for the design of a full scale mechanical physical/chemical 226 Ra removal waste treatment system with an effluent target level of 10 pCi 226 Ra total per litre. The second project addresses problems of the leachability of radionuclides and the stabilization of both uranium mine tailings and BaRaSO 4 sediments from the treatment of acid seepages

  10. The stability of the water column in french ponds (limousin region by the calculation of the wedderburn number

    Directory of Open Access Journals (Sweden)

    TOUCHART L.

    2014-03-01

    Full Text Available Oxygenation and biological life in lakes, reservoirs and ponds depend on the stability of the water column and on the rhythms of stratification and mixing periods. Slight thermal stratification in ponds often is regarded as the same as instability in shallow lakes. Nevertheless fetch in ponds is very short, what reduces the mixing. Wedderburn number (quotient of the buoyancy by the mixing is used to quantify the stability in shallow water bodies. We calculate it for some ponds in French region Limousin, due to original hourly water temperature measurements in all depths and wind data of Météofrance stations. First results show that very high values (above 10 are frequent in summer and spring period (during 41% of the total time of 2 336 hours from May to July in three ponds. That is why we may consider Limousin ponds as stable stratified bodies of water despite their shallowness. Continuous measurements allow to calculate the diurnal cycle and other time scales of the Wedderburn number, with periods of weakening, when air temperatures and surface water temperatures decrease, wind speed increases and when the wind blows in the same direction with the length of the pond. The most complex variable is the depth of the thermocline; a light increase of the breeze thickens the upper warm layer and strengthens the stability, but an important increase of the wind tends to destroy the stratification.

  11. Chemical aspects of the commissioning and early operation of the BNL pond water treatment plant

    International Nuclear Information System (INIS)

    Bradbury, D.; Elder, G.B.

    1981-11-01

    An account is given of the chemical aspects of the work done in commissioning and setting-to-work the pond water treatment plant at BNL. The plant is designed to maintain the fuel pond within the specified chemical conditions for Magnox fuel storage. In normal operation the treatment requirements are met by anion exchange, i.e. the carbonate and other impurity anions in the pond water are replaced by hydroxide held on an anion exchange resin. This method is referred to as ''anion only''. In the commissioning tests the performance of the plant was substantiated by passing simulated pond water of the correct chemical composition through the plant and monitoring the water quality at the plant outlet. During the first phase of operation on the pond itself the plant was operated in non-standard fashion to convert the chemistry from the previous ''carbonate'' regime to the required conditions. (author)

  12. Application of waste stabilization pond's effluent on cultivation of roses (rosa damascena mill)

    International Nuclear Information System (INIS)

    Khan, M.A.; Shaukat, S.; Shahzad, A.; Ahmed, W.

    2011-01-01

    The study focuses on the use of Waste Stabilization Ponds (WSP) effluent for irrigation and also aims to compare the efficiency of effluent with the Hoagland solution. Results revealed that the number of flowers, size of flower and the petals per flower increased by the use of both Hoagland solution and treated effluent while the height of plant and the fresh weight of flowers were increased significantly by the Hoagland solution only. Moreover, the leaves showed high concentration of reducing and non-reducing sugars as compared to flowers whereas, only the leaves of plants which were treated by the ponds effluent had low content of reducing sugars as compared to leaves of untreated plants serving as controls. The variation in chlorophyll content was similar to that of reducing and non-reducing sugars. In addition, leaves of plants that were treated by pond's effluent showed highest concentration of total phenol content. It is concluded that treated effluent is as effective as Hoagland for the irrigation of rose. Additionally, the use of treated effluent for irrigation reduces the demand of fresh water and the use of inorganic fertilizers for the commercial production of roses. (author)

  13. A THEORETICAL AND NUMERICAL STUDY OF THERMOSOLUTAL CONVECTION: STABILITY OF A SALINITY GRADIENT SOLAR POND

    Directory of Open Access Journals (Sweden)

    Djamel Kalache

    2011-01-01

    Full Text Available A theoretical and numerical study of the effect of thermodiffusion on the stability of a gradient layer is presented. It intends to clarify the mechanisms of fluid dynamics and the processes which occur in a salinity gradient solar pond. A mathematical modelling is developed to describe the thermodiffusion contribution on the solar pond where thermal, radiative, and massive fluxes are coupled in the double diffusion. More realistic boundary conditions for temperature and concentration profiles are used. Our results are compared with those obtained experimentally by authors without extracting the heat flux from the storage zone. We have considered the stability analysis of the equilibrium solution. We assumed that the perturbation of quantities such as velocity, temperature, and concentration are infinitesimal. Linearized equations satisfying appropriate prescribed boundary conditions are then obtained and expanded into polynomials form. The Galerkin method along with a symbolic algebra code (Maple are used to solve these equations. The effect of the separation coefficient y is analyzed in the positive and negative case. We have also numerically compared the critical Rayleigh numbers for the onset of convection with those obtained by the linear stability analysis for Le = 100, µa = 0.8, and f = 0.5.

  14. Modelling antibiotics transport in a waste stabilization pond system in Tanzania

    DEFF Research Database (Denmark)

    Moller, Cathrine Christmas; Weisser, Johan J.; Msigala, Sijaona

    2016-01-01

    Antibiotics in wastewater have become a growing problem in urban and peri-urban areas in developing countries as a result of increased use and misuse of antibiotics. A simple dynamic model, that describes the most important removal processes of antibiotic from the wastewater stabilization pond....... Metronidazole was mainly removed through the outlet, but settling and hydrolysis/photolysis also played a role. A sensitivity analysis (±10%) showed that the soil adsorption coefficient, the amount of suspended matter and the ratio of flow rate and volume were the most sensitive parameters. To strengthen...

  15. Influence of pH, Oxygen, and Humic Substances on Ability of Sunlight To Damage Fecal Coliforms in Waste Stabilization Pond Water

    OpenAIRE

    Curtis, Thomas P.; Mara, D. Duncan; Silva, Salomao A.

    1992-01-01

    Simple beaker experiments established that light damages fecal coliforms in waste stabilization ponds by an oxygen-mediated exogenous photosensitization. Wavelengths of up to 700 nm were able to damage bacteria. The ability of wavelengths of >425 nm to damage fecal coliforms was dependent on the presence of dissolved sensitizers. The sensitizers were ubiquitous in raw sewage, unaffected by sewage treatment, not derivatives of bacteriochlorophyll or chlorophyll, absorbed well in UV light, and ...

  16. Principles of Design And Operations Of Wastewater Treatment Pond Systems For Plant Operators, Engineers, And Managers

    Science.gov (United States)

    Wastewater pond systems provide reliable, low cost, and relatively low maintenance treatment for municipal and industrial discharges. However, they do have certain design, operations, and maintenance requirements. While the basic models have not changed in the 30-odd years sinc...

  17. Concentrated Brine Treatment using New Energy in Coal Mine Evaporation Ponds

    Science.gov (United States)

    Li, Ting; Li, Jingfeng

    2017-12-01

    Recently, more and more coal mine water is being advanced treated and reused in China. The concentrated brine that results from advanced treatment methods can only be evaporated in an evaporation pond. Because of limited treatment capabilities and winter freezing, evaporation ponds often overflow, causing environment contamination. In this paper, based on analysis of brine water quality and economic-technical feasibility, we present a suitable treatment method for brine in evaporation ponds as electrodialysis using solar energy. In addition, we propose a new system to treat brine in coal mine evaporation ponds, which is powered by solar and wind. The operating efficiency of this treatment system proposed in this paper can meet the concentrated brine treatment demands in most coal mines in western mining areas of China and it places the photovoltaic power generation plates on the surface of the evaporation pond on a fixed floating island, which reduces any risk associated with land acquisition. This system can enhance brine treatment efficiency, requires a reduced evaporation pond area, increases the utilization of coal mine water, and minimizes the risk of environment contamination.

  18. Tetracycline removal during wastewater treatment in high-rate algal ponds

    International Nuclear Information System (INIS)

    Godos, Ignacio de; Muñoz, Raúl; Guieysse, Benoit

    2012-01-01

    Highlights: ► Tetracycline removal was most likely caused by photodegradation and biosorption. ► Tetracycline presence was linked to biomass deflocculation and poor settleability. ► Deflocculation did not impact treatment efficiency. ► Deflocculation may hamper biomass recover during full-scale treatment. - Abstract: With the hypothesis that light supply can impact the removal of veterinary antibiotics during livestock wastewater treatment in high rate algal ponds (HRAPs), this study was undertaken to determine the mechanisms of tetracycline removal in these systems. For this purpose, two HRAPs were fed with synthetic wastewater for 46 days before tetracycline was added at 2 mg L −1 to the influent of one of the reactors (Te-HRAP). From day 62, dissolved tetracycline removal stabilized around 69 ± 1% in the Te-HRAP and evidence from batch assays suggests that this removal was mainly caused by photodegradation and biosorption. Tetracycline addition was followed by the deflocculation of the Te-HRAP biomass but had otherwise no apparent impact on the removal of the chemical oxygen demand (COD) and biomass productivity. The results from the batch assays also suggested that the light-shading and/or pollutant-sequestrating effects of the biomass limited tetracycline removal in the pond. For the first time, these results demonstrate that the shallow geometry of HRAPs is advantageous to support the photodegradation of antibiotics during wastewater biological treatment but that the presence of these pollutants could hamper biomass recovery. These findings have significant implications for algal-based environmental biotechnologies and must be confirmed under field conditions.

  19. Tetracycline removal during wastewater treatment in high-rate algal ponds

    Energy Technology Data Exchange (ETDEWEB)

    Godos, Ignacio de [School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North (New Zealand); Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011, Valladolid (Spain); Department of Biodiversity and Environmental Management, University of Leon, Campus Vegazana, 24071 Leon (Spain); Munoz, Raul [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011, Valladolid (Spain); Guieysse, Benoit, E-mail: B.J.Guieysse@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North (New Zealand)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Tetracycline removal was most likely caused by photodegradation and biosorption. Black-Right-Pointing-Pointer Tetracycline presence was linked to biomass deflocculation and poor settleability. Black-Right-Pointing-Pointer Deflocculation did not impact treatment efficiency. Black-Right-Pointing-Pointer Deflocculation may hamper biomass recover during full-scale treatment. - Abstract: With the hypothesis that light supply can impact the removal of veterinary antibiotics during livestock wastewater treatment in high rate algal ponds (HRAPs), this study was undertaken to determine the mechanisms of tetracycline removal in these systems. For this purpose, two HRAPs were fed with synthetic wastewater for 46 days before tetracycline was added at 2 mg L{sup -1} to the influent of one of the reactors (Te-HRAP). From day 62, dissolved tetracycline removal stabilized around 69 {+-} 1% in the Te-HRAP and evidence from batch assays suggests that this removal was mainly caused by photodegradation and biosorption. Tetracycline addition was followed by the deflocculation of the Te-HRAP biomass but had otherwise no apparent impact on the removal of the chemical oxygen demand (COD) and biomass productivity. The results from the batch assays also suggested that the light-shading and/or pollutant-sequestrating effects of the biomass limited tetracycline removal in the pond. For the first time, these results demonstrate that the shallow geometry of HRAPs is advantageous to support the photodegradation of antibiotics during wastewater biological treatment but that the presence of these pollutants could hamper biomass recovery. These findings have significant implications for algal-based environmental biotechnologies and must be confirmed under field conditions.

  20. Effect of low quality effluent from wastewater stabilization ponds to receiving bodies, case of Kilombero sugar ponds and Ruaha river, Tanzania.

    Science.gov (United States)

    Machibya, Magayane; Mwanuzi, Fredrick

    2006-06-01

    A study was conducted in a sewage system at Kilombero Sugar Company to review its design, configuration, effectiveness and the quality of influent and effluent discharged into the Ruaha river (receiving body). The concern was that, the water in the river, after effluent has joined the river, is used as drinking water by villages located downstream of the river. Strategic sampling at the inlet of the oxidation pond, at the outlet and in the river before and after the effluent has joined the receiving body (river) was undertaken. Samples from each of these locations were taken three times, in the morning, noon and evening. The sample were then analysed in the laboratory using standard methods of water quality analysis. The results showed that the configuration and or the layout of the oxidation ponds (treatment plant) were not in accordance with the acceptable standards. Thus, the BOD5 of the effluent discharged into the receiving body (Ruaha River) was in the order of 41 mg/l and therefore not meeting several standards as set out both by Tanzanian and international water authorities. The Tanzanian water authorities, for example, requires that the BOD5 of the effluent discharged into receiving bodies be not more that 30 mg/l while the World Health Organization (WHO) requires that the effluent quality ranges between 10 - 30 mg/l. The paper concludes that proper design of treatment plants (oxidation ponds) is of outmost importance especially for factories, industries, camps etc located in rural developing countries where drinking water from receiving bodies like rivers and lakes is consumed without thorough treatment. The paper further pinpoint that both owners of treatment plants and water authorities should establish monitoring/management plan such that treatment plants (oxidation ponds) could be reviewed regarding the change on quantity of influent caused by population increase.

  1. Effect of Low Quality Effluent from Wastewater Stabilization Ponds to Receiving Bodies, Case of Kilombero Sugar Ponds and Ruaha River, Tanzania

    Directory of Open Access Journals (Sweden)

    Fredrick Mwanuzi

    2006-06-01

    Full Text Available A study was conducted in a sewage system at Kilombero Sugar Company to review its design, configuration, effectiveness and the quality of influent and effluent discharged into the Ruaha river (receiving body. The concern was that, the water in the river, after effluent has joined the river, is used as drinking water by villages located downstream of the river. Strategic sampling at the inlet of the oxidation pond, at the outlet and in the river before and after the effluent has joined the receiving body (river was undertaken. Samples from each of these locations were taken three times, in the morning, noon and evening. The sample were then analysed in the laboratory using standard methods of water quality analysis. The results showed that the configuration and or the layout of the oxidation ponds (treatment plant were not in accordance with the acceptable standards. Thus, the BOD5 of the effluent discharged into the receiving body (Ruaha River was in the order of 41 mg/l and therefore not meeting several standards as set out both by Tanzanian and international water authorities. The Tanzanian water authorities, for example, requires that the BOD5 of the effluent discharged into receiving bodies be not more that 30 mg/l while the World Health Organization (WHO requires that the effluent quality ranges between 10 – 30 mg/l. The paper concludes that proper design of treatment plants (oxidation ponds is of outmost importance especially for factories, industries, camps etc located in rural developing countries where drinking water from receiving bodies like rivers and lakes is consumed without thorough treatment. The paper further pinpoint that both owners of treatment plants and water authorities should establish monitoring/management plan such that treatment plants (oxidation ponds could be reviewed regarding the change on quantity of influent caused by population increase.

  2. A Two-Dimensional Numerical Study of Hydrodynamic, Heat and Mass Transfer and Stability in a Salt Gradient Solar Pond

    Directory of Open Access Journals (Sweden)

    Ali Ben Moussa

    2012-10-01

    Full Text Available In this work, the problem of hydrodynamic, heat and mass transfer and stability in a salt gradient solar pond has been numerically studied by means of computational fluid dynamics in transient regime. The body of the simulated pond is an enclosure of height H and length L wherein an artificial salinity gradient is created in order to suppress convective motions induced by solar radiation absorption and to stabilize the solar pond during the period of operation. Here we show the distribution of velocity, temperature and salt concentration fields during energy collection and storage in a solar pond filled with water and constituted by three different salinity zones. The bottom of the pond is blackened and the free-surface is subjected to heat losses by convection, evaporation and radiation while the vertical walls are adiabatic and impermeable. The governing equations of continuity, momentum, thermal energy and mass transfer are discretized by finite–volume method in transient regime. Velocity vector fields show the presence of thin convective cells in the upper convective zone (UCZ and large convective cells in the lower convective zone (LCZ. This study shows the importance of buoyancy ratio in the decrease of temperature in the UCZ and in the preservation of high temperature in the LCZ. It shows also the importance of the thickness of Non-Convective Zone (NCZ in the reduction of the upwards heat losses.

  3. Sorption of lead by settling pond soils after reclamation treatments

    Science.gov (United States)

    Asensio, Verónica; Forján, Rubén; Vega, Flora A.; Andrade, Luisa; Covelo, Emma F.

    2013-04-01

    The reclamation of degraded soils adding waste amendments can add significant concentrations of Pb. Because of this, it is important to know the sorption capacity of Pb by the soils where wastes with high concentrations of this metal are applied. To determine the sorption capacity of Pb by mine soils, before and after reclamation treatments, four different sites were selected at a settling pond mine zone: an untreated one as the control sample (B1), a vegetated one with pines for 21 years (B2v), a vegetated with eucalyptus for 6 years (B3v) and an amended with sewage sludges and paper mill residues for 5 months (B4w). All soils had one horizon except B4w, where twice were sampled (B4Aw and B4Bw). The B4Bw is considered analogous of the control soil. To evaluate the sorption capacity by the soils, sorption isotherms were constructed using single-metal solutions of Pb2+ nitrates (0.03, 0.05, 0.08, 0.1 and 0.5 mmol L-1) containing 0.01 M NaNO3 as background electrolyte (Vega et al., 2009). The overall capacity of the soil to sorb Pb was evaluated as the slope Kr (Vega et al., 2008). The obtained results show that the sorption isotherm of Pb by control soil (B1) and its analogous (B4Bw) are of L-type curve, whereas the sorption isotherms of the treated soils (B2v, B3v and B4Aw) are of H-type curve (Giles et al., 1974). The most of the obtained isotherms do not fit with the models of Langmuir or Freundlich, therefore sorption capacity was evaluated by Kr parameter. According to the obtained Kr parameter, B1 and B4Bw have the lowest Pb sorption capacity (Kr = 0.480 and 0.556, respectively), which increased two times after recently waste amending (B4Aw; Kr = 0.998). The vegetated sites (B2v and B3v) also have higher sorption capacity than B1, but lower than B4Aw (Kr = 0.692 and 0.725, respectively). The highest sorption capacity of Pb by the amended soil is due to its characteristics such as high pH and organic carbon content. This is corroborated by the significantly

  4. Sewage treatment in integrated system of UASB reactor and duckweed pond and reuse for aquaculture.

    Science.gov (United States)

    Mohapatra, D P; Ghangrekar, M M; Mitra, A; Brar, S K

    2012-06-01

    The performance of a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and a duckweed pond containing Lemna gibba was investigated for suitability for treating effluent for use in aquaculture. While treating low-strength sewage having a chemical oxygen demand (COD) of typically less than 200 mg/L, with an increase in hydraulic retention time (HRT) from 10.04 to 33.49 h, COD removal efficiency of the UASB reactor decreased owing to a decrease in organic loading rate (OLR) causing poor mixing in the reactor. However, even at the lower OLR (0.475 kg COD/(m3 x d)), the UASB reactor gave a removal efficiency of 68% for COD and 74% for biochemical oxygen demand (BOD). The maximum COD, BOD, ammonia-nitrogen and phosphate removal efficiencies of the duckweed pond were 40.77%, 38.01%, 61.87% and 88.57%, respectively. Decreasing the OLR by increasing the HRT resulted in an increase in efficiency of the duckweed pond for removal of ammonia-nitrogen and phosphate. The OLR of 0.005 kg COD/(m2 x d) and HRT of 108 h in the duckweed pond satisfied aquaculture quality requirements. A specific growth rate of 0.23% was observed for tilapia fish fed with duckweed harvested from the duckweed pond. The economic analysis proved that it was beneficial to use the integrated system of a UASB reactor and a duckweed pond for treatment of sewage.

  5. Under-performance evaluation and rehabilitation strategy for waste stabilization ponds in Mexico.

    Science.gov (United States)

    Lloyd, B J; Leitner, A R; Vorkas, C A; Guganesharajah, R K

    2003-01-01

    Fourteen high altitude (> 2,500 m amsl) small Waste Stabilisation Pond systems (WSPs) commissioned during the last 12 years in the State of Mexico in Mexico, were built to a common 3-stage design. Each system is comprised of 2 parallel series of bio-digesters, anaerobic and facultative ponds. All fourteen WSP systems produce poor quality effluents, and eight studied in more detail did not meet any of the national standards for discharge to rivers or the standards required for reuse. The under-performance of these WSPs is underlined by the anaerobic condition of the upper reaches of the Lerma river which receives the sewage from the towns served by these treatment plants. Preliminary surveillance diagnostics identified fundamental operational problems in all eight WSP systems located in the upper Lerma catchment. The results of an intensive secondary diagnostic performance evaluation on one system were used to identify the reasons for under-performance. Under-performance was caused by under-design, hydraulic short-circuiting, adverse environmental conditions and poor operation and maintenance. A strategy for improvement of design and operation to meet national standards is presented.

  6. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oocysts in Waste Stabilization Ponds in Northern and Eastern Australia

    Directory of Open Access Journals (Sweden)

    Maxim Sheludchenko

    2016-01-01

    Full Text Available Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP with (n = 1 and without (n = 3 baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci, Campylobacter spp., Salmonella spp., F+ RNA coliphage, adenovirus, Cryptosporidium spp. and Giardia (oo cysts in maturation ponds were measured at the inlet and outlet. Only the baffled pond demonstrated a significant removal of most of the pathogens tested and therefore was subjected to further study by analyzing E. coli and enterococci concentrations at six points along the baffles over five sampling rounds. Using culture-based methods, we found a decrease in the number of E. coli and enterococci from the initial values of 100,000 CFU per 100 mL in the inlet samples to approximately 1000 CFU per 100 mL in the outlet samples for both bacterial groups. Giardia cysts removal was relatively higher than fecal indicators reduction possibly due to sedimentation.

  7. Stability Analysis of a Run-of-River Diversion Hydropower Plant with Surge Tank and Spillway in the Head Pond

    Science.gov (United States)

    Sarasúa, José Ignacio; Elías, Paz; Wilhelmi, José Román; Sánchez, José Ángel

    2014-01-01

    Run-of-river hydropower plants usually lack significant storage capacity; therefore, the more adequate control strategy would consist of keeping a constant water level at the intake pond in order to harness the maximum amount of energy from the river flow or to reduce the surface flooded in the head pond. In this paper, a standard PI control system of a run-of-river diversion hydropower plant with surge tank and a spillway in the head pond that evacuates part of the river flow plant is studied. A stability analysis based on the Routh-Hurwitz criterion is carried out and a practical criterion for tuning the gains of the PI controller is proposed. Conclusions about the head pond and surge tank areas are drawn from the stability analysis. Finally, this criterion is applied to a real hydropower plant in design state; the importance of considering the spillway dimensions and turbine characteristic curves for adequate tuning of the controller gains is highlighted. PMID:25405237

  8. Stability Analysis of a Run-of-River Diversion Hydropower Plant with Surge Tank and Spillway in the Head Pond

    Directory of Open Access Journals (Sweden)

    José Ignacio Sarasúa

    2014-01-01

    Full Text Available Run-of-river hydropower plants usually lack significant storage capacity; therefore, the more adequate control strategy would consist of keeping a constant water level at the intake pond in order to harness the maximum amount of energy from the river flow or to reduce the surface flooded in the head pond. In this paper, a standard PI control system of a run-of-river diversion hydropower plant with surge tank and a spillway in the head pond that evacuates part of the river flow plant is studied. A stability analysis based on the Routh-Hurwitz criterion is carried out and a practical criterion for tuning the gains of the PI controller is proposed. Conclusions about the head pond and surge tank areas are drawn from the stability analysis. Finally, this criterion is applied to a real hydropower plant in design state; the importance of considering the spillway dimensions and turbine characteristic curves for adequate tuning of the controller gains is highlighted.

  9. Sunlight mediated inactivation mechanisms of Enterococcus faecalis and Escherichia coli in clear water versus waste stabilization pond water.

    Science.gov (United States)

    Kadir, Khalid; Nelson, Kara L

    2014-03-01

    Escherichia coli and enterococci have been previously reported to differ in the mechanisms and conditions that affect their sunlight-mediated inactivation in waste stabilization ponds. This study was undertaken to further characterize these mechanisms, using simulated sunlight and single strains of laboratory-grown E. coli and Enterococcus faecalis, with a focus on characterizing the contribution of exogenous reactive oxygen species to the inactivation process. We found that direct damage by UVB light (280-320 nm) was not a significant inactivation mechanism for either organism. E. coli inactivation was strongly dependent on dissolved oxygen concentrations and the presence of UVB wavelengths but E. coli were not susceptible to inactivation by exogenous sensitizers present in waste stabilization pond water. In contrast, E. faecalis inactivation in pond water occurred primarily through exogenous mechanisms, with strong evidence that singlet oxygen is an important transient reactive species. The exogenous mechanism could utilize wavelengths into the visible spectrum and sensitizers were mainly colloidal, distributed between 0.2 and ∼1 μm in size. Singlet oxygen is likely an important endogenous species in both E. faecalis and E. coli inactivation due to sunlight. Although the two organisms had similar inactivation rates in buffered, clear water, the inactivation rate of E. faecalis was 7 times greater than that of E. coli in air-saturated pond water at circumneutral pH due to its susceptibility to exogenous sensitizers and longer wavelengths. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Investigating the Geomorphic Stability of Pond and Plug Projects in the Sierra Nevada

    Science.gov (United States)

    Pond and plug projects have become a popular method of restoration for riparian meadows in the Sierra Nevada Region. Pond and plug is a technique used to restore the floodplain function of a meadow system. Construction involves excavating borrow material, usually from portions o...

  11. Diel changes in water chemistry in an arsenic-rich stream and treatment-pond system

    Science.gov (United States)

    Gammons, C.H.; Grant, T.M.; Nimick, D.A.; Parker, S.R.; DeGrandpre, M.D.

    2007-01-01

    Arsenic concentrations are elevated in surface waters of the Warm Springs Ponds Operable Unit (WSPOU), located at the head of the upper Clark Fork River Superfund site, Montana, USA. Arsenic is derived from historical deposition of smelter emissions (Mill and Willow Creeks) and historical mining and milling wastes (Silver Bow Creek). Although long-term monitoring has characterized the general seasonal and flow-related trends in As concentrations in these streams and the pond system used to treat Silver Bow Creek water, little is known about solubility controls and sorption processes that influence diel cycles in As concentrations. Diel (24-h) sampling was conducted in July 2004 and August 2005 at the outlet of the treatment ponds, at two locations along a nearby reconstructed stream channel that diverts tributary water around the ponds, and at Silver Bow Creek 2??km below the ponds. Dissolved As concentration increased up to 51% during the day at most of the stream sites, whereas little or no diel change was displayed at the treatment-pond outlet. The strong cycle in streams is explained by pH- and temperature-dependent sorption of As onto hydrous metal oxides or biofilms on the streambed. Concentrations of dissolved Ca2+ and HCO3- at the stream sites showed a diel temporal pattern opposite to that of As, and geochemical modeling supports the hypothesis that the concentrations of Ca2+ and HCO3- were controlled by precipitation of calcite during the warm afternoon hours when pH rose above 9.0. Nightly increases in dissolved Mn and Fe(II) concentrations were out of phase with concentrations of other divalent cations and are more likely explained by redox phenomena. ?? 2007 Elsevier B.V. All rights reserved.

  12. A model for cost estimation of system for piggery wastes treatment ponds: a case study

    Directory of Open Access Journals (Sweden)

    Waldir Medri

    2003-12-01

    Full Text Available This article presents the results from the monitoring of a system of ponds for the treatment of piggery wastes, carried out during a 20 months period, with the objective to determine design parameters for the optimization of the treatment system. A series composed of two anaerobic ponds, one facultative pond and one water hyacinth pond, gave an efficiency of 97% in the removal of BOD5, 93% for total phosphorus, 91% for total Kjeldahl nitrogen and a removal of 7 log units for fecal coliforms. A model of the optimization incurred in the treatment of these wastes was developed, within economic concepts.Este artigo apresenta resultados do monitoramento de um sistema de lagoas para tratamento de dejetos suínos, realizados durante um período de 20 meses, com o objetivo de encontrar parâmetros operacionais para otimização do sistema de tratamento. O sistema é composto por duas lagoas anaeróbias, uma facultativa e uma de aguapés, em séries, com uma eficiência de 97% na remoção da DBO5, 93% para o fósforo total, 91% para o nitrogênio total e uma redução de 7 unidades log para os coliformes fecais. Um modelo de otimização para tratamento destes resíduos foi desenvolvido usando os conceitos econômicos.

  13. Pond 1 : closure of the first oil sands tailings pond

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, H.B.; Wells, P.S.; Cox, L. [Suncor Energy Inc., Fort McMurray, AB, (Canada)

    2010-07-01

    This paper described the evolution of reclamation goals and practices that followed the 40-year operating life and closure of an oil sands tailings pond in northeastern Alberta. Pond 1 and the associated containment dyke were first developed without any reclamation goals. The first reclamation practices evolved from a need to prevent erosion to the containment dyke. Reclamation practices developed from research and operational trials seeking to meet increasingly sophisticated reclamation goals, including species selection, propagation techniques, and pest control. The goal became to reclaim developed lands to viable ecosystems compatible with pre-development, changing the focus to the infilling and reclamation of the pond interior. To reduce the reclamation time frame, the Mature Fine Tailings were removed for treatment and replaced with sand beaches to create a trafficable surface and minimize environmental impacts. For reclaiming the pond surface, the landform design objectives were to create a geotechnically stable landscape, reduce the infiltration of precipitation into the beach, create a revegetated landscape to support wildlife and traditional land uses, and create a small wetland without affecting geotechnical stability. The reclamation soil cover design, wildlife enhancement features, wetland design, and revegetation prescriptions were described. In contrast to when the pond began operation, the pond closure was undertaken in a highly regulated environment with a substantial foundation of reclamation knowledge and clearly defined reclamation and end land-use goals. The pond was infilled in 2009, and surface landforming and revegetation were scheduled for completion by the fall 2010. 2 refs., 1 tab., 1 fig.

  14. Greenhouse Gas (CH4, CO2 and N2O) Emission Levels by Wastewater Treatment Plant (WWTP) Ponds in Brazil

    Science.gov (United States)

    Rossete, A. L. M.; Sundefeld Junior, G.; Aparicio, C.; Baldi, G. G.; Montes, C. R.; Piveli, R. P.; Melfi, A. J.

    2015-12-01

    This study measured greenhouse gas emissions (GHG) by Facultative Ponds on Wastewater Treatment Plants. The most studied GHGs include CO2, CH4and N2O. The level of GHG (CO2, CH4 and N2O) emissions by WWTPs in Australian-type stabilization ponds was measured in the city of Lins (22º21'S, 49º50'W), state of São Paulo (SP), Brazil. GHG collection was carried outusing a collection chamber installed at the center of the facultative pond's final third. The effluent's pH and temperature (ET) were registered by probes, and meteorological information regarding air temperature (AT) and solar radiation (SR) were obtained from INMET, Brazil. GHG collection was carried out for 72 consecutive hours in June 2014, on an hourly basis, once every 5 minutes, for the first 30 minutes, and once every 10 minutes from 30 to 50 minutesand subsequently analyzed by gas chromatograph (GC).After three days of data collection, the average AT, SR, ET and pH values were, respectively, 18oC, 2583kJm-2, 23oC and 8.2. Average values for GHG emission levels (CH4, CO2 and N2O) were 79.01; 100.65 and 0.0 mg m-2 h-1, respectively. GHG emission levels were divided into light periods (morning, afternoon and evening)in order to verify the periods with the highest GHG emissions.The highest CH4 emission levels were measured between morning and early afternoon. The maximum CO2 emissions were observed from evening to early morning. N2O emissions were constant and values were close to the ones found in the atmosphere, which shows the emission of N2O by facultative ponds does not contribute to greenhouse gases emissions.The results enabled us to characterize and quantify GHG emission levels per Facultative Pond on Wastewater Treatment Plant. Acknowledgment to FAPESP and SABESP, Brazil.

  15. Ash cements stabilized by supercritical CO2 carbonation for tailings pond overlayer

    International Nuclear Information System (INIS)

    Rubin, J. B.; Taylor, C.M.V.; Paviet-Hartmann, P.; Hartmann, T.

    2000-01-01

    The article describes the general features of supercritical fluids, as well as the application of these fluids to the production of unmodified portland and portland cement modified by incorporation of industrial waste solids, such as oil shale ash. Suitably treated, pre-fabricated cement, incorporating spent oil shale ash, as well as some of the tailings pond waste, could be used as an overlayer for the Sillamaee tailings pond

  16. Olive mill wastewater stabilization in open-air ponds: impact on clay-sandy soil.

    Science.gov (United States)

    Jarboui, Raja; Sellami, Fatma; Kharroubi, Adel; Gharsallah, Néji; Ammar, Emna

    2008-11-01

    The aim of this work was to study the natural biodegradation of the stored olive mill wastewater (OMW) in ponds and the infiltration as well as the impact on soil of the effluent in the evaporation pond used for the storage over the past eight years. For this, two approaches were considered. First, a laboratory-scale column was used for the infiltration of OMW through soil (clay and sand) to predict the effect of the clayey soil in reducing OMW pollution. Second, the ponds including the effluent annually stored and having this clayey structure were investigated. At the laboratory-scale, a modification of OMW contents was noticed, with the elimination of 95% of total suspended solids (TSS), 60% of chemical oxygen demand (COD), 40% of total organic carbon (TOC), 50% of total P, 50% of phenols and 40% of minerals (K+, Mg++ and Na+). The experimented soil was able to restrain the considerable effects of OMW pollution. In the ponds, the granulometric characteristics, the physico-chemical and the biological parameters of the soil profile from the contaminated pond were compared to those of a control soil, located near the contaminated pond. Property modifications of the contaminated soil were noted, especially pH, electrical conductivity, COD and microflora. These changes can be explained by the infiltration of OMW constituents, which were noticed in the soil layers, especially phenolic compounds that have a negative effect on the ground water.

  17. Relationships between ambient geochemistry, watershed land-use and trace metal concentrations in aquatic invertebrates living in stormwater treatment ponds

    Science.gov (United States)

    Karouna-Renier, N.K.; Sparling, D.W.

    2001-01-01

    Stormwater treatment ponds receive elevated levels of metals from urban runoff, but the effects of these pollutants on organisms residing in the ponds are unknown. We investigated the accumulation of Cu, Zn, and Pb by macroinvertebrates collected from stormwater treatment ponds in Maryland serving commercial, highway, residential and open-space watersheds, and determined whether watershed land-use classification influences metal concentrations in macroinvertebrates, sediments, and water. Three types of invertebrate samples were analyzed for molluscs, odonates, and composite. Zn concentrations in odonates from ponds draining watersheds with commercial development (mean=113.82 ug/g) were significantly higher than concentrations in the other land-use categories. Similarly, Cu levels in odonates from commercial ponds (mean=27.12 ug/g) were significantly higher than from highway (mean=20.23 ug/g) and open space (mean=17.79 ug/g) ponds. However, metal concentrations in sediments and water did not differ significantly among land-uses. The results suggest that despite the high variation in ambient metal concentrations within each land-use category, macroinvertebrates in ponds serving commercial watersheds accumulate higher levels of Cu and Zn. The levels of Cu, Zn, and Pb in invertebrates from all ponds were less than dietary concentrations considered toxic to fish.

  18. New approach to solar photo-Fenton operation. Raceway ponds as tertiary treatment technology

    Energy Technology Data Exchange (ETDEWEB)

    Carra, Irene; Santos-Juanes, Lucas [Department of Chemical Engineering, University of Almería, 04120, Almería (Spain); CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120, Almería (Spain); Acién Fernández, Francisco Gabriel [Department of Chemical Engineering, University of Almería, 04120, Almería (Spain); Malato, Sixto [CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120, Almería (Spain); Plataforma Solar de Almería (CIEMAT), 04200, Tabernas, Almería (Spain); Sánchez Pérez, José Antonio, E-mail: jsanchez@ual.es [Department of Chemical Engineering, University of Almería, 04120, Almería (Spain); CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120, Almería (Spain)

    2014-08-30

    Graphical abstract: - Highlights: • Raceway ponds are used for the first time as photo-Fenton reactors. • Raceway ponds are effective and have high treatment capacity (48 mg/h m{sup 2} for 360 L). • The highest treatment capacity occurs with 5.5 mg Fe/L and 15 cm liquid depth. • Low iron concentrations are enough to oxidise the pesticide mixture. • Raceway ponds are a simple and low-cost alternative for micropollutant removal. - Abstract: The photo-Fenton process has proven its efficiency in the removal of micropollutants. However, the high costs usually associated with it prevent a spread of this technology. An important factor affecting costs is the kind of photoreactor used, usually tubular with a reflecting surface. Tubular reactors like compound parabolic collectors, CPCs, involve high capital costs. In comparison, the application of less costly reactors such as the extensive raceway ponds (RPRs) would help to spread the use of the photo-Fenton process as tertiary treatment at commercial scale. As far as the authors know, RPRs have never been used in advanced oxidation processes (AOPs) applications. This work is aimed at studying the applicability of RPRs to remove micropollutants with solar photo-Fenton. For this purpose, a pesticide mixture of commercial acetamiprid (ACTM) and thiabendazole (TBZ) (100 μg/L each) was used in simulated secondary effluent. Iron concentration (1, 5.5 and 10 mg/L) and liquid depth (5, 10 and 15 cm) were studied as process variables. TBZ was removed at the beginning of the treatment (less than 5 min), although ACTM removal times were longer (20–40 min for the highest iron concentrations). High treatment capacity per surface area was obtained (48 mg/h m{sup 2} with 5.5 mg Fe/L and 15 cm liquid depth), proving the feasibility of using RPRs for micropollutant removal.

  19. Odorous compounds treatment of winery and distillery effluents during natural evaporation in ponds.

    Science.gov (United States)

    Bories, A; Sire, Y; Colin, T

    2005-01-01

    During treatment of winery and distillery wastewater by natural evaporation in ponds, formation of malodorous compounds induces harmful olfactory effects. In this work, we studied the origin of malodorous compounds and methods to prevent and treat odours. The formation of volatile fatty acids (VFA) from pure substrates (glycerol, lactic and tartaric acids, ethanol) and complex media (winery and distillery wastewater) was studied. Various anaerobic bacteria ferment the glycerol and produce butyric or propionic acid. Valeric and caproic acids were observed at lower concentrations than butyric and propionic acids, but their malodorous intensities were higher. Microflora produce butyric, valeric, caproic, heptanoic and octanoic acids from ethanol, the main component of winery wastewater. When nitrate (an electron acceptor) is added, catabolism leads to an anaerobic respiration phenomenon (denitrification). The organic compounds are oxidised to CO2 and the nitrate is reduced to N2 (odourless compounds), without VFA formation. The preventive treatment of odours by nitrate addition was tested on an industrial scale in winery and distillery ponds. Furthermore, the study took the effect of nitrate on VFA degradation into consideration. The results make it possible to consider using nitrate for the curative treatment of pond odours.

  20. Enhancing microalgal photosynthesis and productivity in wastewater treatment high rate algal ponds for biofuel production.

    Science.gov (United States)

    Sutherland, Donna L; Howard-Williams, Clive; Turnbull, Matthew H; Broady, Paul A; Craggs, Rupert J

    2015-05-01

    With microalgal biofuels currently receiving much attention, there has been renewed interest in the combined use of high rate algal ponds (HRAP) for wastewater treatment and biofuel production. This combined use of HRAPs is considered to be an economically feasible option for biofuel production, however, increased microalgal productivity and nutrient removal together with reduced capital costs are needed before it can be commercially viable. Despite HRAPs being an established technology, microalgal photosynthesis and productivity is still limited in these ponds and is well below the theoretical maximum. This paper critically evaluates the parameters that limit microalgal light absorption and photosynthesis in wastewater HRAPs and examines biological, chemical and physical options for improving light absorption and utilisation, with the view of enhancing biomass production and nutrient removal. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Baseline study of methane emission from anaerobic ponds of palm oil mill effluent treatment.

    Science.gov (United States)

    Yacob, Shahrakbah; Ali Hassan, Mohd; Shirai, Yoshihito; Wakisaka, Minato; Subash, Sunderaj

    2006-07-31

    The world currently obtains its energy from the fossil fuels such as oil, natural gas and coal. However, the international crisis in the Middle East, rapid depletion of fossil fuel reserves as well as climate change have driven the world towards renewable energy sources which are abundant, untapped and environmentally friendly. Malaysia has abundant biomass resources generated from the agricultural industry particularly the large commodity, palm oil. This paper will focus on palm oil mill effluent (POME) as the source of renewable energy from the generation of methane and establish the current methane emission from the anaerobic treatment facility. The emission was measured from two anaerobic ponds in Felda Serting Palm Oil Mill for 52 weeks. The results showed that the methane content was between 35.0% and 70.0% and biogas flow rate ranged between 0.5 and 2.4 L/min/m(2). Total methane emission per anaerobic pond was 1043.1 kg/day. The total methane emission calculated from the two equations derived from relationships between methane emission and total carbon removal and POME discharged were comparable with field measurement. This study also revealed that anaerobic pond system is more efficient than open digesting tank system for POME treatment. Two main factors affecting the methane emission were mill activities and oil palm seasonal cropping.

  2. Temporal stability of E. coli concentration patterns in two irrigation ponds in Maryland

    Science.gov (United States)

    There are about nine millions ponds in USA, and many of them serve as an important agricultural surface water source. E. coli concentrations are commonly used as indicator organisms to evaluate microbial water quality for irrigation and recreation. Our hypothesis was that there exists a temporally ...

  3. Temporal stability of Escherichia coli concentration patterns in two irrigation ponds in Maryland

    Science.gov (United States)

    Fecal contamination of water sources is an important water quality issue for agricultural irrigation ponds. Escherichia coli is a common microbial indicator used to evaluate recreational and irrigation water quality. We hypothesized that there is a temporally stable pattern of E.coli concentrations ...

  4. Vegetation effects on floating treatment wetland nutrient removal and harvesting strategies in urban stormwater ponds.

    Science.gov (United States)

    Wang, Chih-Yu; Sample, David J; Bell, Cameron

    2014-11-15

    Floating treatment wetlands (FTWs) consist of emergent macrophytes that are placed on a floating mat in a pond for water treatment and aesthetic purposes. FTWs may have unique advantages with respect to treating urban runoff within existing retention ponds for excess nutrients. However, research is lacking in providing guidance on performance of specific species for treating urban runoff, and on timing of harvest. Harvesting is needed to remove nutrients permanently from the retention pond. We investigated vegetation effects on FTWs on nitrogen (N) and phosphorus (P) removal performance and storage in above-ground FTW macrophyte tissues. The study evaluated pickerelweed (PW, Pontederia cordata L.) and softstem bulrush (SB, Schoenoplectus tabernaemontani) over time in microcosms flushed with water obtained from a nearby urban retention pond in northern Virginia near Washington, DC. While the literature exhibits a wide range of experimental sizes, using the term mesocosm, we have chosen the term microcosm to reflect the small size of our vessel; and do not include effects of sediment. The experiment demonstrated PW outperformed SB for P and N removal. Based upon analysis of the accumulated nutrient removal over time, a harvest of the whole PW and SB plants in September or October is recommended. However, when harvesting only the aerial parts, we recommend harvesting above-ground PW tissues in July or August to maximize nutrient removal. This is because PW translocates most of its nutrients to below-ground storage organs in the fall, resulting in less nutrient mass in the above-ground tissue compared to the case in the summer (vegetative stage). Further research is suggested to investigate whether vegetation can be overly damaged from multiple harvests on an annual basis in temperate regions. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

    Energy Technology Data Exchange (ETDEWEB)

    Bill Batchelor; Dong Suk Han; Eun Jung Kim

    2010-01-31

    The overall goal of this project was to evaluate the ability of novel adsorbent/reactants to remove specific toxic target chemicals from ash and scrubber pond effluents while producing stable residuals for ultimate disposal. The target chemicals studied were arsenic (As(III) and As(V)), mercury (Hg(II)) and selenium (Se(IV) and Se(VI)). The adsorbent/reactants that were evaluated are iron sulfide (FeS) and pyrite (FeS{sub 2}). Procedures for measuring concentrations of target compounds and characterizing the surfaces of adsorbent-reactants were developed. Effects of contact time, pH (7, 8, 9, 10) and sulfate concentration (0, 1, 10 mM) on removal of all target compounds on both adsorbent-reactants were determined. Stability tests were conducted to evaluate the extent to which target compounds were released from the adsorbent-reactants when pH changed. Surface characterization was conducted with x-ray photoelectron spectroscopy (XPS) to identify reactions occurring on the surface between the target compounds and surface iron and sulfur. Results indicated that target compounds could be removed by FeS{sub 2} and FeS and that removal was affected by time, pH and surface reactions. Stability of residuals was generally good and appeared to be affected by the extent of surface reactions. Synthesized pyrite and mackinawite appear to have the required characteristics for removing the target compounds from wastewaters from ash ponds and scrubber ponds and producing stable residuals.

  6. Pyrolysis of Algal Biomass Obtained from High-Rate Algae Ponds Applied to Wastewater Treatment

    International Nuclear Information System (INIS)

    Vargas e Silva, Fernanda; Monteggia, Luiz Olinto

    2015-01-01

    This work presents the results of the pyrolysis of algal biomass obtained from high-rate algae ponds treating sewage. The two high-rate algae ponds (HRAP) were built and operated at the São João Navegantes Wastewater Treatment Plant. The HRAP A was fed with raw sewage while the HRAP B was fed with effluent from an upflow anaerobic sludge blanket (UASB) reactor. The HRAP B provided higher productivity, presenting total solids concentration of 487.3 mg/l and chlorophyll a of 7735 mg/l. The algal productivity in the average depth was measured at 41.8 g·m −2 day −1 in pond A and at 47.1 g·m −2 day −1 in pond B. Algae obtained from the HRAP B were separated by the process of coagulation/flocculation and sedimentation. In the presence of alum, a separation efficiency in the range of 97% solid removal was obtained. After centrifugation the biomass was dried and comminuted. The biofuel production experiments were conducted via pyrolysis in a tubular quartz glass reactor which was inserted in a furnace for external heating. The tests were carried out in an inert nitrogen atmosphere at a flow rate of 60 ml/min. The system was operated at 400, 500, and 600°C in order to determine the influence of temperature on the obtained fractional yields. The studies showed that the pyrolysis product yield was influenced by temperature, with a maximum liquid phase (bio-oil and water) production rate of 44% at 500°C, 45% for char and around 11% for gas.

  7. Pyrolysis of Algal Biomass Obtained from High-Rate Algae Ponds Applied to Wastewater Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Vargas e Silva, Fernanda, E-mail: fervs@globo.com; Monteggia, Luiz Olinto [Institute of Hydraulic Research, Federal University of Rio Grande do Sul, Porto Alegre (Brazil)

    2015-06-30

    This work presents the results of the pyrolysis of algal biomass obtained from high-rate algae ponds treating sewage. The two high-rate algae ponds (HRAP) were built and operated at the São João Navegantes Wastewater Treatment Plant. The HRAP A was fed with raw sewage while the HRAP B was fed with effluent from an upflow anaerobic sludge blanket (UASB) reactor. The HRAP B provided higher productivity, presenting total solids concentration of 487.3 mg/l and chlorophyll a of 7735 mg/l. The algal productivity in the average depth was measured at 41.8 g·m{sup −2} day{sup −1} in pond A and at 47.1 g·m{sup −2} day{sup −1} in pond B. Algae obtained from the HRAP B were separated by the process of coagulation/flocculation and sedimentation. In the presence of alum, a separation efficiency in the range of 97% solid removal was obtained. After centrifugation the biomass was dried and comminuted. The biofuel production experiments were conducted via pyrolysis in a tubular quartz glass reactor which was inserted in a furnace for external heating. The tests were carried out in an inert nitrogen atmosphere at a flow rate of 60 ml/min. The system was operated at 400, 500, and 600°C in order to determine the influence of temperature on the obtained fractional yields. The studies showed that the pyrolysis product yield was influenced by temperature, with a maximum liquid phase (bio-oil and water) production rate of 44% at 500°C, 45% for char and around 11% for gas.

  8. PYROLYSIS OF ALGAL BIOMASS OBTAINED FROM HIGH RATE ALGAE PONDS APPLIED TO WASTEWATER TREATMENT

    Directory of Open Access Journals (Sweden)

    Fernanda eVargas E Silva

    2015-06-01

    Full Text Available This work presents the results of the pyrolysis of algal biomass obtained from high rate algae ponds treating sewage. The two high-rate algae ponds (HRAP were built and operated at the São João Navegantes Wastewater Treatment Plant. The HRAP A was fed with raw sewage while the HRAP B was fed with effluent from an Upflow Anaerobic Sludge Blanket (UASB reactor. The HRAP B provided higher productivity, presenting total solids concentration of 487.3mg/l and chlorophyll a of 7735mg/l. The algal productivity in the average depth was measured at 41,8 gm-2day-1 in pond A and at 47.1 gm-2day-1 in pond B. Algae obtained from the HRAP B were separated by the process of coagulation/flocculation and sedimentation. In the presence of alum, a separation efficiency in the range of 97% solids removal was obtained. After centrifugation the biomass was dried and comminuted. The biofuel production experiments were conducted via pyrolysis in a tubular quartz glass reactor which was inserted in a furnace for external heating. The tests were carried out in an inert nitrogen atmosphere at a flow rate of 60ml/min. The system was operated at 400°C, 500°C and 600°C in order to determine the influence of temperature on the obtained fractional yields. The studies showed that the pyrolysis product yield was influenced by temperature, with a maximum liquid phase (bio-oil and water production rate of 44% at 500°C, 45% for char and around 11% for gas.

  9. Microbiological quality of a waste stabilization pond effluent used for restricted irrigation in Valle Del Cauca, Colombia.

    Science.gov (United States)

    Madera, C A; Peña, M R; Mara, D D

    2002-01-01

    This paper discusses the applicability of effluent reuse in agriculture after treatment in a series of anaerobic, facultative and maturation ponds. The WSP system is located in Ginebra municipality, a small town in southwest Colombia. The total HRT is 12 days. Several samples of the final effluent were taken over a 55 day period and were analysed for E. coli, Streptococcus spp. and helminth eggs. Some additional grab samples were taken to determine the presence of pathogenic bacteria such as Salmonella spp. and Shigella spp. The results showed that the system was able to remove 4 log units of E. coli, 1 log unit of Streptococcus spp. and 100% of helminth eggs. Meanwhile, Salmonella spp. were detected in the effluent of the facultative pond whilst Shigella spp. were not detected in any sample. The main species of helminth eggs encountered were Taenia spp., Ascaris spp., Trichuris spp., Hymenolepis nana, H. diminuta and Enterobius vermicularis. Removal efficiencies were satisfactory despite the relatively short HRT. Nevertheless, WHO guidelines were slightly surpassed in the case of E. coli for unrestricted irrigation. The helminth egg value was always below the maximum WHO limit. Hence, this effluent can be safely used for restricted irrigation provided that field workers are protected from direct contact with wastewater given the presence of Salmonella spp. in the facultative pond effluent.

  10. Performance evaluation of cement-stabilized pond ash-rice husk ash-clay mixture as a highway construction material

    Directory of Open Access Journals (Sweden)

    Deepak Gupta

    2017-02-01

    Full Text Available This paper reports the results of an investigation carried out on clay soil stabilized with pond ash (PA, rice husk ash (RHA and cement. Modified Proctor compaction tests were performed in order to investigate the compaction behavior of clay, and California bearing ratio (CBR tests were performed to determine the strength characteristics of clay. For evaluation purpose, the specimens containing different amounts of admixtures were prepared. Clay was replaced with PA and RHA at a dosage of 30%–45% and 5%–20%, respectively. The influence of stabilizer types and dosages on mechanical properties of clay was evaluated. In order to study the surface morphology and crystallization characteristics of the soil samples, scanning electron microscopy (SEM and X-ray diffraction (XRD analyses were carried out, respectively. The results obtained indicated a decrease in the maximum dry density (MDD and a simultaneous increase in the optimum moisture content (OMC with the addition of PA and RHA. Multiple linear regression analysis (MLRA showed that the predicted values of CBR tests are in good agreement with the experimental values. Developed stabilized soil mixtures showed satisfactory strength and can be used for construction of embankments and stabilization of sub-grade soil. The use of locally available soils, PA, RHA, and cement in the production of stabilized soils for such applications can provide sustainability for the local construction industry.

  11. Simultaneous biogas upgrading and centrate treatment in an outdoors pilot scale high rate algal pond

    OpenAIRE

    Posadas, Esther; Marín, David; Blanco, Saúl; Lebrero Fernández, Raquel; Muñoz Torre, Raúl

    2017-01-01

    Producción Científica The bioconversion of biogas to biomethane coupled to centrate treatment was evaluated in an outdoors pilot scale high rate algal pond interconnected to an external CO2-H2S absorption column (AC) via settled broth recirculation. CO2-removal efficiencies ranged from 50 to 95% depending on the alkalinity of the cultivation broth and environmental conditions, while a complete H2S removal was achieved regardless of the operational conditions. A maximum CH4 concentration of...

  12. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops

    International Nuclear Information System (INIS)

    Verbyla, M.E.; Iriarte, M.M.; Mercado Guzmán, A.; Coronado, O.; Almanza, M.; Mihelcic, J.R.

    2016-01-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10 years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1 mL g −1 for coliphage, between 1 and 100 mL g −1 for Giardia and Cryptosporidium, and between 100 and 1000 mL g −1 for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda. - Highlights: • Study of health risks from reclaimed wastewater irrigation from aging pond systems • Coliphages, protozoan parasites, and helminths were measured in water/soil/crops. • Sludge accumulation in ponds may

  13. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops

    Energy Technology Data Exchange (ETDEWEB)

    Verbyla, M.E., E-mail: verbylam@mail.usf.edu [Department of Civil and Environmental Engineering, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL (United States); Iriarte, M.M.; Mercado Guzmán, A.; Coronado, O.; Almanza, M. [Centro de Aguas y Saneamiento Ambiental, Universidad Mayor de San Simón, Cochabamba (Bolivia, Plurinational State of); Mihelcic, J.R. [Department of Civil and Environmental Engineering, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL (United States)

    2016-05-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10 years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1 mL g{sup −1} for coliphage, between 1 and 100 mL g{sup −1} for Giardia and Cryptosporidium, and between 100 and 1000 mL g{sup −1} for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda. - Highlights: • Study of health risks from reclaimed wastewater irrigation from aging pond systems • Coliphages, protozoan parasites, and helminths were measured in water/soil/crops. • Sludge accumulation in

  14. Bench-scale demonstration of treatment technologies for contaminated sediments in Sydney Tar Ponds

    International Nuclear Information System (INIS)

    Volchek, K.; Velicogna, D.; Punt, M.; Wong, B.; Weimer, L.; Tsangaris, A.; Brown, C.E.

    2003-01-01

    A series of bench-scale tests were conducted to determine the capabilities of selected commercially available technologies for treating contaminated sediments from the South Pond of Sydney Tar Ponds. This study was conducted under the umbrella of a technology demonstration program aimed at evaluating technologies to be used in the remediation of such sediments. The following approach was proposed by SAIC Canada for the treatment of the sediments: (1) solvent extraction for the removal of organic contaminants, (2) acid/chelant leaching for the removal of inorganic contaminants such as heavy metals, and (3) plasma hearth process for the destruction of toxic streams resulting from the first two processes. Solvent extraction followed by plasma treatment proved effective for removing and destroying organic contaminants. The removal of metals did not achieve the expected results through leaching. An approach was proposed for treating those sediments based on the results of the study. The approach differed depending on the level of organic content. An assessment of associated process costs for both a pilot-scale field demonstration and a full-scale treatment was provided. 11 tabs., 4 figs

  15. Occurrence of antimicrobials and antimicrobial resistance genes in beef cattle storage ponds and swine treatment lagoons

    International Nuclear Information System (INIS)

    Zhang, Yuping; Zhang, Chiqian; Parker, David B.; Snow, Daniel D.; Zhou, Zhi; Li, Xu

    2013-01-01

    Livestock manure treatment and storage structures are potential environmental sources of antimicrobials and antimicrobial resistance genes (ARGs). In this study, the occurrence of antimicrobials and ARGs was investigated in the water and the sludge compartments of beef cattle storage ponds and swine lagoons. Analysis was focused on two families of antimicrobials (sulfonamide and tetracycline) and the corresponding ARGs (sul1, sul2, tetO, tetQ and tetX). Results showed that the pseudo-partitioning coefficients of tetracyclines were higher than those of sulfonamides, suggesting different distributions of these two classes of antimicrobials between water and sludge. The ARGs tested were detected in nearly all ponds and lagoons, with the highest relative abundance in sul2 at 6.3 × 10 −1 copies per 16S rRNA gene. A positive correlation was observed between total sul genes and total sulfonamides in water while the correlation was negative in sludge. No significant correlation was found between total tet genes and total tetracyclines in either water or sludge, but significant correlations were observed for certain individual tet genes. Ammonia concentrations strongly correlated with all ARGs except tetX. This study provided quantitative information on the occurrence of antimicrobials and ARGs in the liquid and solid compartments of typical manure treatment and storage structures. - Highlights: • Partitioning of antimicrobials between water and sludge is compound specific. • Antimicrobial resistance genes occurred in both water and sludge. • The ARG abundance varied more substantially in swine lagoons than in cattle ponds. • Correlations between ARGs and antimicrobials are system dependent

  16. Assessment of the nutrient removal effectiveness of floating treatment wetlands applied to urban retention ponds.

    Science.gov (United States)

    Wang, Chih-Yu; Sample, David J

    2014-05-01

    The application of floating treatment wetlands (FTWs) in point and non-point source pollution control has received much attention recently. Although the potential of this emerging technology is supported by various studies, quantifying FTW performance in urban retention ponds remains elusive due to significant research gaps. Actual urban retention pond water was utilized in this mesocosm study to evaluate phosphorus and nitrogen removal efficiency of FTWs. Multiple treatments were used to investigate the contribution of each component in the FTW system with a seven-day retention time. The four treatments included a control, floating mat, pickerelweed (Pontederia cordata L.), and softstem bulrush (Schoenoplectus tabernaemontani). The water samples collected on Day 0 (initial) and 7 were analyzed for total phosphorus (TP), total particulate phosphorus, orthophosphate, total nitrogen (TN), organic nitrogen, ammonia nitrogen, nitrate-nitrite nitrogen, and chlorophyll-a. Statistical tests were used to evaluate the differences between the four treatments. The effects of temperature on TP and TN removal rates of the FTWs were described by the modified Arrhenius equation. Our results indicated that all three FTW designs, planted and unplanted floating mats, could significantly improve phosphorus and nitrogen removal efficiency (%, E-TP and E-TN) compared to the control treatment during the growing season, i.e., May through August. The E-TP and E-TN was enhanced by 8.2% and 18.2% in the FTW treatments planted with the pickerelweed and softstem bulrush, respectively. Organic matter decomposition was likely to be the primary contributor of nutrient removal by FTWs in urban retention ponds. Such a mechanism is fostered by microbes within the attached biofilms on the floating mats and plant root surfaces. Among the results of the four treatments, the FTWs planted with pickerelweed had the highest E-TP, and behaved similarly with the other two FTW treatments for nitrogen removal

  17. [Task 1.] Biodenitrification of low nitrate solar pond waters using sequencing batch reactors. [Task 2.] Solidification/stabilization of high strength and biodenitrified heavy metal sludges with a Portland cement/flyash system

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa, L.; Cook, N.E.; Siegrist, R.L.; Mosher, J.; Terry, S.; Canonico, S.

    1995-09-22

    Process wastewater and sludges were accumulated on site in solar evaporation ponds during operations at the Department of Energy's Rocky Flats Plant (DOE/RF). Because of the extensive use of nitric acid in the processing of actinide metals, the process wastewater has high concentrations of nitrate. Solar pond waters at DOE/RF contain 300-60,000 mg NO{sub 3}{sup {minus}}/L. Additionally, the pond waters contain varying concentrations of many other aqueous constituents, including heavy metals, alkali salts, carbonates, and low level radioactivity. Solids, both from chemical precipitation and soil material deposition, are also present. Options for ultimate disposal of the pond waters are currently being evaluated and include stabilization and solidification (S/S) by cementation. Removal of nitrates can enhance a wastes amenability to S/S, or can be a unit operation in another treatment scheme. Nitrate removal is also a concern for other sources of pollution at DOE/RF, including contaminated groundwater collected by interceptor trench systems. Finally, nitrate pollution is a problem at many other DOE facilities where actinide metals were processed. The primary objective of this investigation was to optimize biological denitrification of solar pond waters with nitrate concentrations of 300--2,100 mg NO{sub 3}{sup {minus}}/L to below the drinking water standard of 45 mg NO{sub 3}{sup {minus}}/L (10 mg N/L). The effect of pH upon process stability and denitrification rate was determined. In addition, the effect Cr(VI) on denitrification and fate of Cr(VI) in the presence of denitrifying bacteria was evaluated.

  18. Mini-review: high rate algal ponds, flexible systems for sustainable wastewater treatment.

    Science.gov (United States)

    Young, P; Taylor, M; Fallowfield, H J

    2017-06-01

    Over the last 20 years, there has been a growing requirement by governments around the world for organisations to adopt more sustainable practices. Wastewater treatment is no exception, with many currently used systems requiring large capital investment, land area and power consumption. High rate algal ponds offer a sustainable, efficient and lower cost option to the systems currently in use. They are shallow, mixed lagoon based systems, which aim to maximise wastewater treatment by creating optimal conditions for algal growth and oxygen production-the key processes which remove nitrogen and organic waste in HRAP systems. This design means they can treat wastewater to an acceptable quality within a fifth of time of other lagoon systems while using 50% less surface area. This smaller land requirement decreases both the construction costs and evaporative water losses, making larger volumes of treated water available for beneficial reuse. They are ideal for rural, peri-urban and remote communities as they require minimum power and little on-site management. This review will address the history of and current trends in high rate algal pond development and application; a comparison of their performance with other systems when treating various wastewaters; and discuss their potential for production of added-value products. Finally, the review will consider areas requiring further research.

  19. Nitrate pollution of groundwater around a sewage stabilization pond, Kerala India

    International Nuclear Information System (INIS)

    Vasu, K.; Shahul Hameed, A.; Velayudhan, K.T.; Jacob, S.; Mathew, M.

    1998-01-01

    An investigation was carried out to determine the influence of the sewage stabilisation pont of the Calicut Medical College on the quality of water in the open dug wells which are situated in and around the stabilisation pond. The study revealed that domestic wells are becoming increasingly polluted with nitrate in spite of heavy rainfall in the region. The level of nitrate in the observation wells was found to be vary widely during different seasons: from 1.1 to 49.8, 0.7 to 19.5 and from 2.1 to 38.3 mg/l during pre-monsoon, monsoon and post-monsoon periods, respectively. One well had nitrate exceeding the maximum permissible limit specified for drinking water by Bureau of Indian Standards. The problem is more pronounced in summer when the level of nitrate is observed to be on the higher side. (author)

  20. Microbial Community Strucure of a Tropical Wastewater Stabilization Pond (Cajati, Brazil)

    DEFF Research Database (Denmark)

    Nishio, Sandra; Schramm, Andreas; Pellizari, V.

    . Other bacterial groups detected were Gammaproteobacteria, Planctomycetes, and the Cytophaga-Flavobacterium and Chloroflexus groups. Archaea accounted for 5% in the sludge, probably due to the presence of methanogens in the sludge. The absence of depth- and site-related variation...... municipal wastewater of the city of Cajati, Brazil; in addition, 27 stations across the pond were sampled at an intermediate depth. DGGE revealed little variation of the bacterial diversity among water depths and stations, while the bacterial communities differed between water and sludge, and between...... seasons. CARD-FISH successfully detected 55-85% and 40-50% of all cells in the water and sludge samples, respectively, and generally confirmed the DGGE results. The bacterial community was dominated by unicellular cyanobacteria, followed by either Beta- or Alphaproteobacteria, depending on the season...

  1. Biological and Irradiation Treatment of Mix Industrial Wastewater in Flood Mitigation Pond at Prai Industrial Zone

    International Nuclear Information System (INIS)

    Khomsaton Abu Bakar; Jamaliah Sharif; Selambakkanu, S.; Ming, T.M.; Natasha Isnin; Hasnul Nizam Osman; Khasmidatul Akma Mohd Khairul Azmi

    2014-01-01

    In this work, activated sludge process and E-Beam was used to treat mixed industrial waste water from mitigation pond A. The objectives of this study to analyze the effect of mix liquor volatile suspended solid (MLVSS) concentration on the properties of wastewater and duration of time taken to achieve steady stage condition for biological treatment. Besides that, effect of electron beam energy on the characteristic of wastewater after irradiation with electron beam machine EPS 3000 was studied as well. The result shows removal percentage of COD, suspended solid and color was linearly proportional with MLVSS. Maximum reduction values recorded for COD, suspended solid and color removal was 69.4, 73.0 and 43.7 % respectively with 3500 mg/l MLVSS at 48 h HRT. In irradiation treatment, significant reduction of COD was obtained with the increase of electron beam energy but the results for suspended solid and color was not favorable. (author)

  2. Zinc Regime in the Sewage Sludge-Soil-Plant System of a City Waste Water Treatment Pond

    OpenAIRE

    Lacatusu Radu; Lacatusu Anca-Rovena; Lungu Mihaela; Stanciu Burileanu Mihaela Monica; Vrînceanu Andrei

    2014-01-01

    The sewage sludge from wastewater treatment plant of Iasi, a city with 300,000 inhabitants, for domestic and industrial origin, was stored in a mud pond arranged on an area of 18,920 m2. Chemical analyzes of the sludge showed that, of all the chemical elements determined, only Zn is found at pollutant level (5739 mg∙kg-1), i.e. almost 30 times more than the maximum allowable limit for Zn in soil and 45 times more than the Zn content of the soil on which the mud pond has been set. Over time, t...

  3. Wastewater treatment high rate algal ponds (WWT HRAP) for low-cost biofuel production.

    Science.gov (United States)

    Mehrabadi, Abbas; Craggs, Rupert; Farid, Mohammed M

    2015-05-01

    Growing energy demand and water consumption have increased concerns about energy security and efficient wastewater treatment and reuse. Wastewater treatment high rate algal ponds (WWT HRAPs) are a promising technology that could help solve these challenges concurrently where climate is favorable. WWT HRAPs have great potential for biofuel production as a by-product of WWT, since the costs of algal cultivation and harvest for biofuel production are covered by the wastewater treatment function. Generally, 800-1400 GJ/ha/year energy (average biomass energy content: 20 GJ/ton; HRAP biomass productivity: 40-70 tons/ha/year) can be produced in the form of harvestable biomass from WWT HRAP which can be used to provide community-level energy supply. In this paper the benefits of WWT HRAPs are compared with conventional mass algal culture systems. Moreover, parameters to effectively increase algal energy content and overall energy production from WWT HRAP are discussed including selection of appropriate algal biomass biofuel conversion pathways. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Selection of natural treatment processes for algae removal from stabilisation ponds effluents in Brasilia, using multicriterion methods.

    Science.gov (United States)

    Neder, K D; Carneiro, G A; Queiroz, T R; de Souza, M A A

    2002-01-01

    A multicriterion methodology is used in the evaluation and selection of the most appropriate alternative(s) for removing algae from stabilisation ponds effluents in a case study in Brasilia. For this purpose, five different natural treatment processes are tested at pilot scale: rock filter, sand filter, floating aquatic plants, constructed wetlands, and overland flow. These pilot units were constructed in Brasilia and set in parallel, each one receiving a portion of the effluent that comes from an existing wastewater treatment plant composed of preliminary treatment, UASB reactors, and high-rate stabilisation ponds. Several evaluation criteria are used in order to relate the capabilities of the post-treatment processes to the multiple objectives in this case. Two multicriterion decision-aid methods--compromise programming and ELECTRE-III--are used to select the most satisfying processes. The top ranking alternatives are indicated for subsequent studies, considering the possible implementation of these technologies to existing plants.

  5. Disinfection and removal of human pathogenic bacteria in arctic waste stabilization ponds

    DEFF Research Database (Denmark)

    Huang, Yannan; Hansen, Lisbeth Truelstrup; Ragush, Colin M.

    2017-01-01

    cool summer treatment season. With relevance to public health, the objectives of this paper were to determine if treatment in arctic WSPs resulted in the disinfection (i.e., removal of fecal indicator bacteria, Escherichia coli) and removal of selected human bacterial pathogens from the treated...

  6. Comparison of experimental ponds for the treatment of dye wastewater under controlled and semi-natural conditions.

    Science.gov (United States)

    Yaseen, Dina A; Scholz, Miklas

    2017-07-01

    This study compares the performance of simulated shallow ponds vegetated with Lemna minor L. under controlled and semi-natural conditions for the treatment of simulated wastewater containing textile dyes. The objectives were to assess the water quality outflow parameters, the potential of L. minor concerning the removal of chemical oxygen demand (COD) and four azo dyes (Acid blue 113, reactive blue 198, Direct Orange 46 and Basic Red 46) and the plants' growth rate. Findings show that all mean outflow values of COD, total dissolved solids (TDS) and electrical conductivity (EC) were significantly (p removal was low for both experiments. The outflow TDS values were acceptable for all ponds. The pond systems were able to reduce only BR46 significantly (p Removals under laboratory conditions were better than those for semi-natural environments, indicating the suitability of operating the pond system as a polishing step in warmer regions. The mean outflow values of zinc and copper were below the thresholds set for drinking and irrigation waters and acceptable for L. minor. The dyes inhibited the growth of the L. minor.

  7. Management and treatment of landfill leachate by a system of constructed wetlands and ponds in Singapore.

    Science.gov (United States)

    Sim, C H; Quek, B S; Shutes, R B E; Goh, K H

    2013-01-01

    Lorong Halus, Singapore's first landfill leachate treatment system, consists of a pre-treatment system (8,000 m(2)), five constructed reed beds (38,000 m(2)), five polishing ponds (13,000 m(2)), an education centre and a learning trail for visitors. Eight species of wetland plants (total 160,000 plants) were selected for their ability to uptake nutrients, tolerance to low phosphorus concentrations and resistance to pest infestations. The wetland was launched in March 2011 and water quality monitoring started in April 2011. The removal efficiencies of the pre-treatment system from April 2011 to August 2012 are biochemical oxygen demand (BOD5) 57.4%; chemical oxygen demand (COD) 23.6%; total suspended solids (TSS) 55.1%; ammoniacal nitrogen (NH4-N) 76.8%; total phosphorus (TP) 33.3% and total nitrogen (TN) 60.2%. Removal efficiencies of the reed beds are BOD5 47.0%; COD 42.2%; TSS 57.0%; NH4-N 82.5%; TP 29.3% and TN 83.9%. Plant growth is generally satisfactory, but the lower than designed volume of leachate has adversely affected some sections of plants and resulted in uneven flow distribution in reed beds. The plant management programme includes improving plant regrowth by harvesting of alternate strips of plants and replanting. The treated effluent meets water quality limits for discharge to the public sewer and is subsequently treated by the NEWater treatment system, which recycles water for industrial and indirect potable use.

  8. Simultaneous biogas upgrading and centrate treatment in an outdoors pilot scale high rate algal pond.

    Science.gov (United States)

    Posadas, Esther; Marín, David; Blanco, Saúl; Lebrero, Raquel; Muñoz, Raúl

    2017-05-01

    The bioconversion of biogas to biomethane coupled to centrate treatment was evaluated in an outdoors pilot scale high rate algal pond interconnected to an external CO 2 -H 2 S absorption column (AC) via settled broth recirculation. CO 2 -removal efficiencies ranged from 50 to 95% depending on the alkalinity of the cultivation broth and environmental conditions, while a complete H 2 S removal was achieved regardless of the operational conditions. A maximum CH 4 concentration of 94% with a limited O 2 and N 2 stripping was recorded in the upgraded biogas at recycling liquid/biogas ratios in the AC of 1 and 2. Process operation at a constant biomass productivity of 15gm -2 d -1 and the minimization of effluent generation supported high carbon and nutrient recoveries in the harvested biomass (C=66±8%, N=54±18%, P≈100% and S=16±3%). Finally, a low diversity in the structure of the microalgae population was promoted by the environmental and operational conditions imposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A modeling approach to estimate the solar disinfection of viral indicator organisms in waste stabilization ponds and surface waters.

    Science.gov (United States)

    Kohn, Tamar; Mattle, Michael J; Minella, Marco; Vione, Davide

    2016-01-01

    Sunlight is known to be a pertinent factor governing the infectivity of waterborne viruses in the environment. Sunlight inactivates viruses via endogenous inactivation (promoted by absorption of solar light in the UVB range by the virus) and exogenous processes (promoted by adsorption of sunlight by external chromophores, which subsequently generate inactivating reactive species). The extent of inactivation is still difficult to predict, as it depends on multiple parameters including virus characteristics, solution composition, season and geographical location. In this work, we adapted a model typically used to estimate the photodegradation of organic pollutants, APEX, to explore the fate of two commonly used surrogates of human viruses (coliphages MS2 and ϕX174) in waste stabilization pond and natural surface water. Based on experimental data obtained in previous work, we modeled virus inactivation as a function of water depth and composition, as well as season and latitude, and we apportioned the contributions of the different inactivation processes to total inactivation. Model results showed that ϕX174 is inactivated more readily than MS2, except at latitudes >60°. ϕX174 inactivation varies greatly with both season (20-fold) and latitude (10-fold between 0 and 60°), and is dominated by endogenous inactivation under all solution conditions considered. In contrast, exogenous processes contribute significantly to MS2 inactivation. Because exogenous inactivation can be promoted by longer wavelengths, which are less affected by changes in season and latitude, MS2 exhibits smaller fluctuations in inactivation throughout the year (10-fold) and across the globe (3-fold between 0 and 60°) compared to ϕX174. While a full model validation is currently not possible due to the lack of sufficient field data, our estimated inactivation rates corresponded well to those reported in field studies. Overall, this study constitutes a step toward estimating microbial water

  10. Operational Limitations of Arctic Waste Stabilization Ponds: Insights from Modeling Oxygen Dynamics and Carbon Removal

    DEFF Research Database (Denmark)

    Ragush, Colin M.; Gentleman, Wendy C.; Hansen, Lisbeth Truelstrup

    2018-01-01

    that it was the difference in phytoplankton growth rates, and the associated change in photosynthetic oxygen production, that mainly contribute to creating differences in CBOD5 removal rates and the development of aerobic conditions. The model was also sensitive to atmospheric aeration rates at low temperature, providing...... environmental factors affecting treatment performance in arctic WSPs. A sensitivity analysis was used to provide a quantification of the relative uncertainties of parameters that exist within the described modeling framework. The model was able to qualitatively reproduce mesocosm experiment trends...... in phytoplankton growth, dissolved oxygen concentration, and the reduction of carbonaceous biochemical oxygen demand on Day 5 (CBOD5). These results demonstrated that CBOD5 reduction and oxygen state are very sensitive to organic loading regimes at low temperatures (5-15°C). The sensitivity analysis identified...

  11. Storage pond

    International Nuclear Information System (INIS)

    Hunter, E.; Watson, E.

    1983-01-01

    A pond is described for the storage of hazardous materials, such as irradiated nuclear fuel elements, under water. Upper and lower impervious membranes extend without interruption beneath the floor of the pond and the edges of the membranes lead into a trench surrounding the pond. Any leakage through the floor is directed normally by the upper membrane into the trench. The lower membrane provides an additional impervious barrier in the event of a leak in the upper membrane and again directs the leakage into the trench thereby avoiding contamination of the ground beneath the pond. (author)

  12. Estimation of VOC emissions from produced-water treatment ponds in Uintah Basin oil and gas field using modeling techniques

    Science.gov (United States)

    Tran, H.; Mansfield, M. L.; Lyman, S. N.; O'Neil, T.; Jones, C. P.

    2015-12-01

    Emissions from produced-water treatment ponds are poorly characterized sources in oil and gas emission inventories that play a critical role in studying elevated winter ozone events in the Uintah Basin, Utah, U.S. Information gaps include un-quantified amounts and compositions of gases emitted from these facilities. The emitted gases are often known as volatile organic compounds (VOCs) which, beside nitrogen oxides (NOX), are major precursors for ozone formation in the near-surface layer. Field measurement campaigns using the flux-chamber technique have been performed to measure VOC emissions from a limited number of produced water ponds in the Uintah Basin of eastern Utah. Although the flux chamber provides accurate measurements at the point of sampling, it covers just a limited area of the ponds and is prone to altering environmental conditions (e.g., temperature, pressure). This fact raises the need to validate flux chamber measurements. In this study, we apply an inverse-dispersion modeling technique with evacuated canister sampling to validate the flux-chamber measurements. This modeling technique applies an initial and arbitrary emission rate to estimate pollutant concentrations at pre-defined receptors, and adjusts the emission rate until the estimated pollutant concentrations approximates measured concentrations at the receptors. The derived emission rates are then compared with flux-chamber measurements and differences are analyzed. Additionally, we investigate the applicability of the WATER9 wastewater emission model for the estimation of VOC emissions from produced-water ponds in the Uintah Basin. WATER9 estimates the emission of each gas based on properties of the gas, its concentration in the waste water, and the characteristics of the influent and treatment units. Results of VOC emission estimations using inverse-dispersion and WATER9 modeling techniques will be reported.

  13. Zinc Regime in the Sewage Sludge-Soil-Plant System of a City Waste Water Treatment Pond

    Directory of Open Access Journals (Sweden)

    Lacatusu Radu

    2014-10-01

    Full Text Available The sewage sludge from wastewater treatment plant of Iasi, a city with 300,000 inhabitants, for domestic and industrial origin, was stored in a mud pond arranged on an area of 18,920 m2. Chemical analyzes of the sludge showed that, of all the chemical elements determined, only Zn is found at pollutant level (5739 mg∙kg-1, i.e. almost 30 times more than the maximum allowable limit for Zn in soil and 45 times more than the Zn content of the soil on which the mud pond has been set. Over time, the content of Zn in the mud pond, but also from soil to which it has been placed, has become upper the normal content of the surrounding soil up to a depth of 260 cm. On the other hand, the vegetation installed on sewage sludge in the process of mineralization, composed predominantly of Phragmites, Rumex, Chenopodium, and Aster species had accumulated in roots, stems and leaves Zn quantities equivalent to 1463 mg Kg-1, 3988 mg Kg-1, 1463 mg Kg-1, respectively, 1120 mg∙Kg-1. The plants in question represents the natural means of phytoremediation, and sewage sludge as such may constitute a fertilizer material for soils in the area, on which Zn deficiency in maize has been recorded. In addition, the ash resulted from the incineration of plants loaded with zinc may constitute, in its turn, a good material for fertilizing of the soils that are deficient in zinc.

  14. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops.

    Science.gov (United States)

    Verbyla, M E; Iriarte, M M; Mercado Guzmán, A; Coronado, O; Almanza, M; Mihelcic, J R

    2016-05-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1mLg(-1) for coliphage, between 1 and 100mLg(-1) for Giardia and Cryptosporidium, and between 100 and 1000mLg(-1) for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Using full-scale duckweed ponds as the finish stage for swine waste treatment with a focus on organic matter degradation.

    Science.gov (United States)

    Mohedano, R A; Costa, R H R; Hofmann, S M; Belli Filho, P

    2014-01-01

    The rapid increase in the number of swine has caused pronounced environmental impacts worldwide, especially on water resources. As an aggregate, smallholdings have an important role in South American pork production, contributing to the net diffusion of pollution. Thus, duckweed ponds have been successfully used for swine waste polishing, mainly for nutrient removal. Few studies have been carried out to assess organic matter degradation in duckweed ponds. Hence, the present study evaluated the efficiency of two full-scale duckweed ponds for organic matter reduction of swine waste on small pig farms. Duckweed ponds, in series, received the effluent after an anaerobic biodigester and storage pond, with a flow rate of 1 m(3) day(-1). After 1 year of monitoring, an improvement in effluent quality was observed, with a reduction in biochemical oxygen demand (BOD) and total chemical oxygen demand (tCOD), respectively, of 94.8 and 96.7%, operating at a loading rate of approximately 27 kgBOD ha(-1) day(-1) and 131 kgCOD ha(-1) day(-1). Algae inhibition due to duckweed coverage was strongly observed in the pond effluent, where chlorophyll a and turbidity remained below 25 μg L(-1) and 10 NTU. Using the study conditions described herein, duckweed ponds were shown to be a suitable technology for swine waste treatment, contributing to the environmental sustainability of rural areas.

  16. Algal removal using biological filter treatment system in eutrophip ponds; Seibutsu rokaho ni yoru fueiyokashita ike numa no sorui jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.; Chiba, N.; Yamada, K.; Xu, K.; Sudo, R. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1997-01-10

    This paper describes experimental results of algal removal using biological filter treatment system in eutrophic ponds. Removal characteristics of individual algae were investigated using two experimental systems in a polluted pond located at Sendai city. One is a horizontal flow system packed with ringlace as a contact media, and the other is an upflow filtration system packed with nonwoven fabric. Balance of Chlorophyll-a (Chl-a) in the treatment tank was examined in the field. As a result, it was found that the removal rate of green algae was lower than that of red algae using both of the systems. Using both of the systems, conversions of inflow Chl-a into attached substance were between 3 and 5%, and 50 to 60 % of attached Chl-a was removed by back-washing. Using the horizontal flow filter treatment system, the conversion of Chl-a into deposits was about 10%. In addition, is described the predaceous decomposition of algae by Protozoa and Metazoa in the treatment tank. 18 refs., 7 figs., 9 tabs.

  17. A rational approach for evaluation and screening of treatment and disposal options for the solar pond sludges at Rocky Flats

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, K.S.

    1995-12-31

    This document consists of information about the treatment options for the sludge that is located in the evaporation ponds at the Rocky Flats Plant. The sludges are mixed low-level radioactive wastes whose composition and character were variable. Sludges similar to these are typically treated prior to ultimate disposal. Disposal of treated sludges includes both on-site and off-site options. The rational approach described in this paper is useful for technology evaluation and screening because it provides a format for developing objectives, listing alternatives, and weighing the alternatives against the objectives and against each other.

  18. A rational approach for evaluation and screening of treatment and disposal options for the solar pond sludges at Rocky Flats

    International Nuclear Information System (INIS)

    Dickerson, K.S.

    1995-01-01

    This document consists of information about the treatment options for the sludge that is located in the evaporation ponds at the Rocky Flats Plant. The sludges are mixed low-level radioactive wastes whose composition and character were variable. Sludges similar to these are typically treated prior to ultimate disposal. Disposal of treated sludges includes both on-site and off-site options. The rational approach described in this paper is useful for technology evaluation and screening because it provides a format for developing objectives, listing alternatives, and weighing the alternatives against the objectives and against each other

  19. Olive mill wastewater evaporation management using PCA method Case study of natural degradation in stabilization ponds (Sfax, Tunisia).

    Science.gov (United States)

    Jarboui, Raja; Sellami, Fatma; Azri, Chafai; Gharsallah, Néji; Ammar, Emna

    2010-04-15

    Olive mill wastewater (OMW) evaporation ponds management was investigated in five serial evaporation open-air multiponds of 50 ha located in Sfax (Tunisia). Physico-chemical parameters and microbial flora evolution were considered. Empirical models describing the OMW characteristic changes with the operation time were established and Principal Component Analysis (PCA) described the correlation between physico-chemical and biological parameters. COD, BOD, total solids, polyphenols and electrical conductivity exhibited first-order models. Four groups exhibited high correlations. The first included temperature, density, COD, TSS, TS, BOD, VS, TOC, TKN, polyphenols and minerals. The second group was made up of yeasts and moulds. The third group was established with phenolic compounds, total sugars, fats, total phosphorous, NH(4)(+) and pH. The fourth group was constituted by exclusively aerobic bacteria. Bacterial-growth toxic effect was exhibited by high organic load, ash content and polyphenols, whereas moulds and yeasts were more adapted to OMW. During the storage, all the third group parameter values decreased and were inversely related to the others. In the last pond, COD, BOD, TS and TSS rates were reduced by 40%, 50%, 50% and 75% respectively. The evaporation and the biological activity were the main processes acting, predicting the OMW behavior during evaporation in air-open ponds. 2009 Elsevier B.V. All rights reserved.

  20. ROCTECtm STABILIZATION TREATMENT OF WERF ASH

    Energy Technology Data Exchange (ETDEWEB)

    Paul A. Lessing; William J. Quapp; Gary Renlund; Bob Clark; Colin Hundley; James Cornwell; Dave Schlier; John Bulko; Gene Pollack

    1998-10-01

    The objective of this project is to demonstrate a process to stabilize mixed waste flyash generated by the combustion of mixed waste at the Idaho National Engineering & Environmental Laboratory's (INEEL's) Waste Experimental Reduction Facility (WERF) incinerator such that it will meet Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions (LDRs) Universal Treatment Standards.

  1. Stability of tailings ponds in the mining district of Mazarron (SE Spain): potential risks for the Moreras Rambla; Estudio de estabilidad en depositos de lodos del Distrito Minero de Mazarron (SE Espana): Riesgos potenciales sobre la Rambla de Las Moreras

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, J. A.; Martinez-Martinez, S.; Martinez-Pagan, P.; Zornoza, R.; Carmona, D. M.; Faz, A.

    2011-07-01

    We have used geochemical, geophysical and geotechnical techniques to identify and quantify the environmental risks of the San Cristobal and Las Moreras tailing ponds, which have been left since the closing down of Pb-Zn mining activities in a semi-arid Mediterranean area. The results show that the tailings ponds present a potential risk to nearby ecosystems because of their high acidity, high salinity and high concentrations of metals, especially Pb and Zn contain. If the pond dams were to fail or if erosion carried dry sludge to the surrounding areas, the result would be pollution, acidification, salinization, compaction and nutrient depletion of the soil, thus reducing the biodiversity of the area. Geoelectrical tomography has shown the depth of the deposits, their volume and the geomorphology of the basement. The profiles reveal that in none of the pseudo-sections are there any regions betraying cracks that might affect the stability of the structures. In fact, geotechnical studies indicate that on a large scale both ponds are stable. Nevertheless, if we contemplate circular rupture and seismic action in the San Cristobal pond, the safety factor values become critical. It is recommended, therefore, that periodic inspections should be carried out to assess moisture, upsurges and settlements in the dam. To reduce erosion of the surface sludge in the tailing ponds we suggest the application of alkaline and organic remediation so as to improve their geochemical characteristics and encourage the establishment of natural vegetation. (Author) 48 refs.

  2. Effect of probiotic and sand filtration treatments on water quality and growth of tilapia (Oreochromis niloticus) and pangas (Pangasianodon hypophthalmus) in earthen ponds of southern Bangladesh

    DEFF Research Database (Denmark)

    Mahmud, Sultan; Ali, Mohammad Lokman; Alam, Md Ariful

    2016-01-01

    . The fish were stocked at a density of 20,000 fish ha−1 and reared for 7 months. Compared to untreated ponds, treatments of probiotic products or sand filtration in earthen ponds resulted in a higher O2 content, higher water transparency, less ammonium, and fewer cyanobacteria. Weight gain for individual......Effects of water treatment by two probiotic products (PondPlus® and AquaPhoto®) and sand filtration were studied on growth performance of tilapia (Oreochromis niloticus) and pangas (Pangasianodon hypophthalmus) stocked at tilapia:pangas ratio of 5:3 in traditional earthen ponds in Bangladesh...

  3. Removal of fecal indicators and pathogens in a waste stabilization pond system treating municipal wastewater in India.

    Science.gov (United States)

    Tyagi, Vinay Kumar; Kazmi, A A; Chopra, A K

    2008-11-01

    This study assess the removal of fecal indicators (i.e., total coliforms, fecal coliforms, E. coli, fecal streptococci, and pathogens [Salmonella sp. and helminth eggs]) in a full-scale facultative and maturation pond system with primary screening and manual grit removal facility. The capacity of the plant is 6 ML/d. The results showed that the system was able to remove approximately 2.0 to 3.5 log units of fecal indicators and almost 100% of helminth eggs. Meanwhile, Salmonella was not eliminated significantly, as only 1.26 log units removal was found. Removal efficiency of fecal indicator bacteria was reported maximum during summers (3.4 to 4.0 log units) and minimum (1.9 to 2.0 log units) in winters. Further efforts were made to seek the correlation between key physicochemical wastewater quality parameters (biochemical oxygen demand, turbidity, and suspended solids) and indicator microorganisms (total coliforms, fecal coliforms, and fecal streptococci). Among all these parameters, suspended solids showed the highest correlation coefficient (r2) with total coliforms (0.79), fecal coliforms (0.78), and fecal streptococci (0.75). These correlations manifest that the improvement of microbiological quality of wastewater is strongly linked to the removal of suspended solids.

  4. Frozen ponds

    DEFF Research Database (Denmark)

    Langer, M; Westermann, S.; Anthony, K. Walter

    2015-01-01

    on the thermal state of the surrounding permafrost; during the freezing period they prolong the period of time during which thawed soil material is available for microbial decomposition.  This study presents net CH4 production rates during the freezing period from ponds within a typical lowland tundra landscape...... in northern Siberia. Rate estimations were based on CH4 concentrations measured in surface lake ice from a variety of waterbody types. Vertical profiles along ice blocks showed an exponential increase in CH4 concentration with depth. These CH4 profiles were reproduced by a 1-D mass balance model and the net...... (0.01 to 0.14 mgCH4 m-2 day-1). In contrast, ponds exhibiting clear signs of erosion yielded net CH4 production rates of the order of 10-7 mol m-2 s-1 (140 mg CH4 m-2 day-1). Our results therefore indicate that once a particular threshold in thermal erosion has been crossed, ponds can develop into major CH4...

  5. Emhanced pond efficiency through solar radiation | Agunwamba ...

    African Journals Online (AJOL)

    The effect of enhanced solar radiation on the performance of waste stabilization pond (WSP) was investigated in this study. The analysis was performed with data collected from four pilot ponds operated in parallel; one without enhanced solar radiation and the rest with solar irradiation. The latter gave higher efficiency.

  6. Technical Proposal on the Treatment of the Influent of the José Antonio Alzate dam Using Aerobic Pond System

    Directory of Open Access Journals (Sweden)

    E. López–Galván

    2010-01-01

    Full Text Available In México, discharge of waste water not treated is a common problem; this is the case of the Lerma River, where the original clean water contribution of the Almoloya–Lerma–San Bartolo timber–roof system, located in the valley of Toluca, State of México, was replaced by the wastewater of the valley. The attempts to clean the water before their spill have been unfruitful and this has caused the present anaerobic conditions of the river in its entire route including the first receiving stage that is the José Antonio Alzate Dam (PJAA, becoming a potential source of diseases and a useless water body. In this work we evaluate the treatment efficiency of experimental waste water pond system. The treatment system was constructed with 5 screens which formed 6 internal channels and it had an operation in continuous form by 26 weeks, providing it with continuously polluted water of the Lerma River. We found that the efficiency of reduction of the organic matter reported as BOD5 was 83% and it is carried out in the first channel after 7 days of hydraulic retention verifying that the channels do not work like lagoons in series. With the collected data we calculated, through the application of design equations, the factor of decay of organic matter "k" and the number of dispersion "d", specific for the type of treatment and environmental conditions of the site. The required surface of treatment calculated to reach the efficiency of reduction of the BOD5 obtained experimentally. Thus, a surface of: 1 281.6 hectares distributed in 13 lagoons that can deal with a volume 8 646, 70 m3/h was determined. Since this was a bigger surfaces than that of the dam, the available area was evaluated to make a proposal closer to reallity.

  7. Characterisation of winery wastewater from continuous flow settling basins and waste stabilisation ponds over the course of 1 year: implications for biological wastewater treatment and land application.

    Science.gov (United States)

    Welz, P J; Holtman, G; Haldenwang, R; le Roes-Hill, M

    2016-11-01

    Wineries generate 0.2 to 4 L of wastewater per litre of wine produced. Many cellars make use of irrigation as a means of disposal, either directly or after storage. In order to consider the potential downstream impacts of storage/no storage, this study critically compared the seasonal organic and inorganic composition of fresh winery effluent with effluent that had been stored in waste stabilisation ponds. Ethanol and short chain volatile fatty acids were the main contributors to chemical oxygen demand (COD), with average concentrations of 2,086 and 882 mgCOD/L, respectively. Total phenolics were typically present in concentrations wastewater treatment by natural nitrogen supplementation. It is therefore recommended that if land requirements can be met, winery effluent should be stored in ponds prior to treatment.

  8. A Summary Description of a Computer Program Concept for the Design and Simulation of Solar Pond Electric Power Generation Systems

    Science.gov (United States)

    1984-01-01

    A solar pond electric power generation subsystem, an electric power transformer and switch yard, a large solar pond, a water treatment plant, and numerous storage and evaporation ponds. Because a solar pond stores thermal energy over a long period of time, plant operation at any point in time is dependent upon past operation and future perceived generation plans. This time or past history factor introduces a new dimension in the design process. The design optimization of a plant must go beyond examination of operational state points and consider the seasonal variations in solar, solar pond energy storage, and desired plant annual duty-cycle profile. Models or design tools will be required to optimize a plant design. These models should be developed in order to include a proper but not excessive level of detail. The model should be targeted to a specific objective and not conceived as a do everything analysis tool, i.e., system design and not gradient-zone stability.

  9. Gaseous by-products from pulsed arc electrohydraulic discharge treatment of contaminated stormwater ponds

    Energy Technology Data Exchange (ETDEWEB)

    Li, O.L.; Guo, Y. [McMaster Univ., Hamilton, ON (Canada). Dept. of Civil Engineering; Chang, J.S. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics; He, Z. [Huazhong Univ. of Science and Technology, Huazhong (China). Dept. of High Voltage Engineering

    2010-07-01

    The application of pulsed arc electrohydraulic discharge (PAED) has been applied for different environmental applications, such as drinking water and wastewater treatment. The pulsed arc system operates at 10-2 to 10 Hz and the peak current is above 1 kA with a microsecond order voltage rise. The system injects energy directly into an aqueous solution through a plasma channel formed by a high-current/high voltage electrical discharge between two submersed electrodes. However, the process results in ultra-violet (UV) radiation, radical reactions, ionic and electronic reactions, thermal dissociation and strong pressure waves. This paper presented a proposed mechanism of PAED water treatment where the liquid-phase electrical discharge facilitates concurrent removal of chemical contaminants and inactivation of viruses and bacteria. The technology has also been used in dislodgement of mussels and removal and prevention of biofilms on cooling and water intake pipes. The paper investigated the optical emission spectrum, UV dose as well as gaseous by-products emission during the PAED treatment of contaminated stormwater. It was concluded that PAED discharges in stormwater vaporizes and ionizes liquid molecules and results in high electron temperatures and plasma densities. The study showed that contaminated stormwater can be safely discharged to receiving water bodies after PAED treatment. 11 refs., 1 tab., 8 figs.

  10. How Healthy Is Our Pond?

    Science.gov (United States)

    Sterling, Donna R.; Hargrove, Dori L.

    2014-01-01

    With crosscutting concepts such as stability and change in the "Next Generation Science Standards," this article was written for those who have wondered how to teach these concepts in a way that is relevant to students. In this investigation, students ask the question, "Why is the pond dirty?" As students investigate the health…

  11. The study on the effect of low-temperature heat treatment on tissue dehydration fish pond

    Directory of Open Access Journals (Sweden)

    N. S. Rodionova

    2013-01-01

    Full Text Available The paper is studied thermo-moisture treatment of carp on the provisional application of vacuum packaging. The degree of hydration of the carp meat tissues equally depends on the prepackaging, as well as the characteristics of the fluid in the chamber system. With increasing temperature the degree of hydration of meat carp tissue decreases with the reduction of the difference in its numerical values of packed and unpacked samples. Obtained a graph of depence dependence of the speed of carp meat tissue dehydration of the processing temperature. Revealed that the presence of plastic packaging, as well as wetting fluid help reduce the dehydration speed of carp meat tissues.

  12. Site-specific health and safety plan 100-D Pond remediation project

    International Nuclear Information System (INIS)

    Hobbs, B.J.

    1996-06-01

    The 100-D Ponds are located north of the northern perimeter fence of the 100-D Area. The ponds were excavated in a preexisting basin that had been used for disposal of coal ash. There are two ponds, one used as a settling pond and the other a percolation pond. Liquid effluent from the 100-D process sewers was discharged to the ponds from 1977 through 1987; after 1987 the ponds received backwash and rinsate from the 100-D water treatment facilities. All discharges to the ponds ceased in June 1994, and the ponds were allowed to dry up

  13. Prediction of the waste stabilization pond performance using linear multiple regression and multi-layer perceptron neural network: a case study of Birjand, Iran

    Directory of Open Access Journals (Sweden)

    Maryam Khodadadi

    2016-06-01

    Full Text Available Background: Data mining (DM is an approach used in extracting valuable information from environmental processes. This research depicts a DM approach used in extracting some information from influent and effluent wastewater characteristic data of a waste stabilization pond (WSP in Birjand, a city in Eastern Iran. Methods: Multiple regression (MR and neural network (NN models were examined using influent characteristics (pH, Biochemical oxygen demand [BOD5], temperature, chemical oxygen demand [COD], total suspended solids [TSS], total dissolved solid [TDS], electrical conductivity [EC] and turbidity as the regression input vectors. Models were adjusted to input attributes, effluent BOD5 (BODout and COD (CODout. The models performances were estimated by 10-fold external cross-validation. An internal 5-fold cross-validation was also used for the training data set in NN model. The models were compared using regression error characteristic (REC plot and other statistical measures such as relative absolute error (RAE. Sensitivity analysis was also applied to extract useful knowledge from NN model. Results: NN models (with RAE = 78.71 ± 1.16 for BODout and 83.67 ± 1.35 for CODout and MR models (with RAE = 84.40% ± 1.07 for BODout and 88.07 ± 0.80 for CODout indicate different performances and the former was better (P < 0.05 for the prediction of both effluent BOD5 and COD parameters. For the prediction of CODout the NN model with hidden layer size (H = 4 and decay factor = 0.75 ± 0.03 presented the best predictive results. For BODout the H and decay factor were found to be 4 and 0.73 ± 0.03, respectively. TDS was found as the most descriptive influent wastewater characteristics for the prediction of the WSP performance. The REC plots confirmed the NN model performance superiority for both BOD and COD effluent prediction. Conclusion: Modeling the performance of WSP systems using NN models along with sensitivity analysis can offer better

  14. Performance evaluation of a natural treatment system for small communities, composed of a UASB reactor, maturation ponds (baffled and unbaffled) and a granular rock filter in series.

    Science.gov (United States)

    Dias, D F C; Passos, R G; Rodrigues, V A J; de Matos, M P; Santos, C R S; von Sperling, M

    2018-02-01

    Post-treatment of anaerobic reactor effluent with maturation ponds is a good option for small to medium-sized communities in tropical climates. The treatment line investigated, operating in Brazil, with an equivalent capacity to treat domestic sewage from 250 inhabitants, comprised a upflow anaerobic sludge blanket reactor followed by two shallow maturation ponds (unbaffled and baffled) and a granular rock filter (decreasing grain size) in series, requiring an area of only 1.5 m 2  inhabitant -1 . With an overall hydraulic retention time of only 6.7 days, the performance was excellent for a natural treatment system. Based on over two years of continuous monitoring, median removal efficiencies were: biochemical oxygen demand = 93%, chemical oxygen demand = 79%, total suspended solids = 87%, ammonia = 43% and Escherichia coli = 6.1 log units. The final effluent complied with European discharge standards and WHO guidelines for some forms of irrigation, and appeared to be a suitable alternative for treating domestic sewage for small communities in warm areas, especially in developing countries.

  15. SISTEM PENGOLAHAN AIR ASAM TAMBANG PADA WATER POND DAN APLIKASI MODEL ENCAPSULATION IN-PIT DISPOSAL PADA WASTE DUMP TAMBANG BATUBARA (Acid Mine Drainage Treatment System in Water Pond and Application of Encapsulation In-Pit Disposal Model in Waste Dump

    Directory of Open Access Journals (Sweden)

    Andy R. Erwin Wijaya

    2010-03-01

    . The control system of acid mine drainage contamination included treatment of acid mine drainage into water pond and management of oxide/benign waste on the waste dump. Treatment method is neutralization of acid mine drainage into water pond using alkali reagent. The most effective and economic alkali reagent is limestone. Amount of limestone needed to neutralize of acid mine drainage (5040 m3 into water pond is 104.56 kg. The management of oxide/benign waste is application of encapsulation in-pit disposal model. This model is more effective to prevent acid mine drainage formed. Cover materials are often clay subsoils and have been used for covering to prevent oxidation. The clay have high compaction rates and low permeability (2.3148 x 10-9 m/s and this material is sufficient availability.

  16. Long-term assessment at field scale of Floating Treatment Wetlands for improvement of water quality and provision of ecosystem services in a eutrophic urban pond.

    Science.gov (United States)

    Olguín, Eugenia J; Sánchez-Galván, Gloria; Melo, Francisco J; Hernández, Víctor J; González-Portela, Ricardo E

    2017-04-15

    Pollution of urban water bodies requires stringent control measures and the development of low-cost and highly efficient alternative technologies. In contrast to Constructed Wetlands, Floating Treatment Wetlands (FTWs) have the advantage of not requiring large surface of land since they operate in situ. However, there is limited information about their long-term evaluation while operating at field scale. The aim of this work was to assess the performance of FTWs using a combination of Pontederia sagittata and Cyperus papyrus for the improvement of the water quality and provision of ecosystem services of a eutrophic urban pond. The FTWs were built with low-cost material easy to acquire and to ensemble. Two FTWs (17.5m 2 and 33m 2 ) located in Pond 1 within a complex of 4 urban artificial ponds were evaluated for two years. They promoted an increase in the dissolved oxygen (D.O.) within a range of 15 to 67%, a removal of fecal coliforms in the range of 9 to 86% and a nitrate removal in the range of 9 to 76%. The plant productivity reached a maximum of 363g dm m -2 d -1 in the FTW1 and 536g dm m -2 d -1 in the FTW2 during the period March-June 2016. The TKN and the TP content in the plant were in the range of 18.3 to 28.1 and of 0.05 to 0.196gkg -1 dry matter, respectively. In conclusion, the tested FTWs have proved to be a very beneficial low-cost technology for the improvement of water quality and provision of ecosystem services. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. ANL-W 779 pond seepage test

    International Nuclear Information System (INIS)

    Braun, D.R.

    1992-11-01

    The ANL-W 779 sanitary wastewater treatment ponds are located on the Idaho National Engineering Laboratory (INEL), north of the Argonne National Laboratory -- West (ANL-W) site A seepage test was performed for two Argonne National Laboratory -- West (ANL-W) sanitary wastewater treatment ponds, Facility 779. Seepage rates were measured to determine if the ponds are a wastewater land application facility. The common industry standard for wastewater land application facilities is a field-measured seepage rate of one quarter inch per day or greater

  18. 100-D Ponds closure plan. Revision 1

    International Nuclear Information System (INIS)

    Petersen, S.W.

    1997-09-01

    The 100-D Ponds is a Treatment, Storage, and Disposal (TSD) unit on the Hanford Facility that received both dangerous and nonregulated waste. This Closure Plan (Rev. 1) for the 100-D Ponds TSD unit consists of a RCRA Part A Dangerous Waste Permit Application (Rev. 3), a RCRA Closure Plan, and supporting information contained in the appendices to the plan. The closure plan consists of eight chapters containing facility description, process information, waste characteristics, and groundwater monitoring data. There are also chapters containing the closure strategy and performance standards. The strategy for the closure of the 100-D Ponds TSD unit is clean closure. Appendices A and B of the closure plan demonstrate that soil and groundwater beneath 100-D Ponds are below cleanup limits. All dangerous wastes or dangerous waste constituents or residues associated with the operation of the ponds have been removed, therefore, human health and the environment are protected. Discharges to the 100-D Ponds, which are located in the 100-DR-1 operable unit, were discontinued in June 1994. Contaminated sediment was removed from the ponds in August 1996. Subsequent sampling and analysis demonstrated that there is no contamination remaining in the ponds, therefore, this closure plan is a demonstration of clean closure

  19. 100-D Ponds closure plan. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, S.W.

    1997-09-01

    The 100-D Ponds is a Treatment, Storage, and Disposal (TSD) unit on the Hanford Facility that received both dangerous and nonregulated waste. This Closure Plan (Rev. 1) for the 100-D Ponds TSD unit consists of a RCRA Part A Dangerous Waste Permit Application (Rev. 3), a RCRA Closure Plan, and supporting information contained in the appendices to the plan. The closure plan consists of eight chapters containing facility description, process information, waste characteristics, and groundwater monitoring data. There are also chapters containing the closure strategy and performance standards. The strategy for the closure of the 100-D Ponds TSD unit is clean closure. Appendices A and B of the closure plan demonstrate that soil and groundwater beneath 100-D Ponds are below cleanup limits. All dangerous wastes or dangerous waste constituents or residues associated with the operation of the ponds have been removed, therefore, human health and the environment are protected. Discharges to the 100-D Ponds, which are located in the 100-DR-1 operable unit, were discontinued in June 1994. Contaminated sediment was removed from the ponds in August 1996. Subsequent sampling and analysis demonstrated that there is no contamination remaining in the ponds, therefore, this closure plan is a demonstration of clean closure.

  20. Beyond best management practices: pelagic biogeochemical dynamics in urban stormwater ponds.

    Science.gov (United States)

    Williams, Clayton J; Frost, Paul C; Xenopoulos, Marguerite A

    2013-09-01

    Urban stormwater ponds are considered to be a best management practice for flood control and the protection of downstream aquatic ecosystems from excess suspended solids and other contaminants. Following this, urban ponds are assumed to operate as unreactive settling basins, whereby their overall effectiveness in water treatment is strictly controlled by physical processes. However, pelagic microbial biogeochemical dynamics could be significant contributors to nutrient and carbon cycling in these small, constructed aquatic systems. In the present study, we examined pelagic biogeochemical dynamics in 26 stormwater ponds located in southern Ontario, Canada, during late summer. Initially, we tested to see if total suspended solids (TSS) concentration, which provides a measure of catchment disturbance, landscape stability, and pond performance, could be used as an indirect predictor of plankton stocks in stormwater ponds. Structural equation modeling (SEM) using TSS as a surrogate for external loading suggested that TSS was an imperfect predictor. TSS masked plankton-nutrient relationships and appeared to reflect autochthonous production moreso than external forces. When TSS was excluded, the SEM model explained a large amount of the variation in dissolved organic matter (DOM) characteristics (55-75%) but a small amount of the variation in plankton stocks (3-38%). Plankton stocks were correlated positively with particulate nutrients and extracellular enzyme activities, suggesting rapid recycling of the fixed nutrient and carbon pool with consequential effects on DOM. DOM characteristics across the ponds were mainly of autochthonous origin. Humic matter from the watershed formed a larger part of the DOM pool only in ponds with low productivity and low dissolved organic carbon concentrations. Our results suggest that in these small, high nutrient systems internal processes might outweigh the impact of the landscape on carbon cycles. Hence, the overall benefit that

  1. Mathematical modeling of dissolved oxygen in fish ponds ...

    African Journals Online (AJOL)

    The effects of organic feeds, aeration and fish activity were added to the model developed by Kayombo et al. for Waste Stabilization Ponds (Ecological Modelling 127(2000): 21 - 31) to reflect the situation in fish ponds. Model calibration and validation was done by use of average DO, pH, temperature, COD, CO2 and algae ...

  2. High-rate algal pond coupled with a matrix of Spirogyra sp. for treatment of rural streams with nutrient pollution.

    Science.gov (United States)

    Kim, Taeeung; Ren, Xianghao; Chae, Kyu-Jung

    2018-05-01

    This study evaluated the unique features of a filamentous algae matrix (FAM) that can be applied to high rate algal ponds (HRAPs) as a promising way to remove nutrient from polluted rural streams. The results show that the HRAPs, coupled with the FAM, effectively removed nitrogen and phosphorus (79.8% and 81.2%, respectively), and achieved high production of DO, with a maximum of 11.0 g O 2 g FAM -1 d -1 . The FAM functioned wells as a screen to prevent excessive algae loss from the system and obtained relatively high biomass growth rate (0.032 mg L -1 d -1 for nitrogen and 0.344 mg L -1 d -1 for phosphorus). The harvested FAM was a useful fertilizer and the rate of addition of FAM were 1.52 kg d -1 ha -1 of nitrogen and 0.44 kg d -1 ha -1 of phosphorus. Thus, combining the HRAP with the FAM was an effective nutrient removal and resource utilization system for rural streams. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. The stability of drinking water treatment residue with ozone treatment.

    Science.gov (United States)

    Liu, Xin; Wu, Yu; He, Rui; Jiang, He-Long; Wang, Changhui

    2017-06-12

    The best management of drinking water treatment residue (DWTR) in environmental remediation should be based on comprehensively understanding the effectiveness and risk of DWTR. In this study, the variation in physicochemical properties, metal lability, and adsorption capability of DWTR under oxidizing condition were investigated. The oxidizing condition was set up using ozone treatment, and the laboratory incubation test were performed within 50 d in association with thermogravimetry, Fourier Transform Infrared Spectrometry, specific surface area and porosity analyzer, fractionation, and P adsorption test. The results showed that ozone treatment had limited effect on the properties of organic matter, the lability of Al, Cu, and Fe, the P adsorption capability, and the distributions of the adsorbed P in DWTR, but the treatment increased N 2 sorption/desorption, specific surface area, total pore volume of DWTR and led to the transformation of Mn from acid-soluble to reducible fractions. These findings demonstrated that DWTR generally kept stable under oxidizing environment; even oxidizing environment may induce a tendency of increasing the adsorption capability and decreasing the environmental risk of DWTR. Accordingly, the effectiveness and safety of DWTR can be maintained under natural aerobic environment, and DWTR is a reliable adsorbent that could be recycled in environmental remediation.

  4. Biomass granulation in an upflow anaerobic sludge blanket reactor treating 500 m3/day low-strength sewage and post treatment in high-rate algal pond.

    Science.gov (United States)

    Chatterjee, Pritha; Ghangrekar, M M

    2017-09-01

    A pilot-scale upflow anaerobic sludge blanket-moving bed biofilm (UASB-MBB) reactor followed by a high-rate algal pond (HRAP) was designed and operated to remove organic matter, nutrients and pathogens from sewage and to facilitate reuse. For an influent chemical oxygen demand (COD) concentration of 233 ± 20 mg/L, final effluent COD was 50 ± 6 mg/L. Successful biomass granulation was observed in the sludge bed of the upflow anaerobic sludge blanket (UASB) reactor after 5 months of operation. Ammonia removal in HRAP was 85.1 ± 2.4% with average influent and effluent ammonia nitrogen concentrations of 20 ± 3 mg/L and 3 ± 1 mg/L, respectively. Phosphate removal after treatment in the HRAP was 91 ± 1%. There was a 2-3 log scale pathogen removal after treatment in HRAP with most probable number (MPN) of the final effluent being 600-800 per 100 mL, which is within acceptable standards for surface irrigation. The blackwater after treatment in UASB-MBBR-HRAP is being reused for gardening and landscaping. This proper hydro-dynamically designed UASB reactor demonstrated successful granulation and moving bed media improved sludge retention in UASB reactor. This combination of UASB-MBB reactor followed by HRAP demonstrated successful sewage treatment for a year covering all seasons.

  5. Effects of different pretreatments on the performance of ceramic ultrafiltration membrane during the treatment of oil sands tailings pond recycle water: a pilot-scale study.

    Science.gov (United States)

    Loganathan, Kavithaa; Chelme-Ayala, Pamela; El-Din, Mohamed Gamal

    2015-03-15

    Membrane filtration is an effective treatment method for oil sands tailings pond recycle water (RCW); however, membrane fouling and rapid decrease in permeate flux caused by colloids, organic matter, and bitumen residues present in the RCW hinder its successful application. This pilot-scale study investigated the impact of different pretreatment steps on the performance of a ceramic ultrafiltration (CUF) membrane used for the treatment of RCW. Two treatment trains were examined: treatment train 1 consisted of coagulant followed by a CUF system, while treatment train 2 included softening (Multiflo™ system) and coagulant addition, followed by a CUF system. The results indicated that minimum pretreatment (train 1) was required for almost complete solids removal. The addition of a softening step (train 2) provided an additional barrier to membrane fouling by reducing hardness-causing ions to negligible levels. More than 99% removal of turbidity and less than 20% removal of total organic carbon were achieved regardless of the treatment train used. Permeate fluxes normalized at 20 °C of 127-130 L/m(2) h and 111-118 L/m(2) h, with permeate recoveries of 90-93% and 90-94% were observed for the treatment trains 1 and 2, respectively. It was also found that materials deposited onto the membrane surface had an impact on trans-membrane pressure and influenced the required frequencies of chemically enhanced backwashes (CEBs) and clean-in-place (CIP) procedures. The CIP performed was successful in removing fouling and scaling materials such that the CUF performance was restored to baseline levels. The results also demonstrated that due to their low turbidity and silt density index values, permeates produced in this pilot study were suitable for further treatment by high pressure membrane processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Study the Stability of a Wastewater Treatment Unit using LABVIEW

    Directory of Open Access Journals (Sweden)

    Ghainm M. Alwan

    2013-05-01

    Full Text Available This study was devoted to limit the stability conditions of the wastewater treatment unit.       LABVIEW was a powerful and versatile graphical programming language in automation control and date acquisition of the system. The on-line show that accurate and stable control responses were obtained in the present work. The actual phase plane proved to a better technique to limit the regions of the non-linear system stability compared to other theoretical techniques. Limit cycle did not appear in the present system. 

  7. Ecosystem function in waste stabilisation ponds: Improving water quality through a better understanding of biophysical coupling

    Science.gov (United States)

    Ghadouani, Anas; Reichwaldt, Elke S.; Coggins, Liah X.; Ivey, Gregory N.; Ghisalberti, Marco; Zhou, Wenxu; Laurion, Isabelle; Chua, Andrew

    2014-05-01

    Wastewater stabilisation ponds (WSPs) are highly productive systems designed to treat wastewater using only natural biological and chemical processes. Phytoplankton, microbial communities and hydraulics play important roles for ecosystem functionality of these pond systems. Although WSPs have been used for many decades, they are still considered as 'black box' systems as very little is known about the fundamental ecological processes which occur within them. However, a better understanding of how these highly productive ecosystems function is particularly important for hydrological processes, as treated wastewater is commonly discharged into streams, rivers, and oceans, and subject to strict water quality guidelines. WSPs are known to operate at different levels of efficiency, and treatment efficiency of WSPs is dependent on physical (flow characteristics and sludge accumulation and distribution) and biological (microbial and phytoplankton communities) characteristics. Thus, it is important to gain a better understanding of the role and influence of pond hydraulics and vital microbial communities on pond performance and WSP functional stability. The main aim of this study is to investigate the processes leading to differences in treatment performance of WSPs. This study uses a novel and innovative approach to understand these factors by combining flow cytometry and metabolomics to investigate various biochemical characteristics, including the metabolite composition and microbial community within WSPs. The results of these analyses will then be combined with results from the characterisation of pond hydrodynamics and hydraulic performance, which will be performed using advanced hydrodynamic modelling and advanced sludge profiling technology. By understanding how hydrodynamic and biological processes influence each other and ecosystem function and stability in WSPs, we will be able to propose ways to improve the quality of the treatment using natural processes, with

  8. Degradation and monitoring of acetamiprid, thiabendazole and their transformation products in an agro-food industry effluent during solar photo-Fenton treatment in a raceway pond reactor.

    Science.gov (United States)

    Carra, Irene; Sirtori, Carla; Ponce-Robles, Laura; Sánchez Pérez, José Antonio; Malato, Sixto; Agüera, Ana

    2015-07-01

    In this study, pesticides acetamiprid and thiabendazole and their transformation products (TPs), seven from each pesticide, were successfully monitored during solar photo-Fenton treatment in a real secondary effluent from an agro-food industry spiked with 100μgL(-1) of each pesticide. To this end, a highly sensitive procedure was developed, based on liquid chromatography (LC) coupled to hybrid quadrupole-linear ion trap mass spectrometry (QqLIT-MS). In addition, finding low-cost and operational technology for the application of AOPs would then facilitate their use on a commercial level. Simple and extensive photoreactors such as raceway pond reactors (RPRs) are therefore proposed as an alternative for the application of solar photo-Fenton. Results showed that high degradation could be achieved in a complex water matrix (>99% TBZ and 91% ACTM in 240min) using a 120-L RPR pilot plant as novel technology. The analyses indicated that after the treatment only three TPs from ACTM were still present in the effluent, while the others had been removed. The study showed that the goal of either just removing the parent compounds, or going one step further and removing all the TPs, can significantly change the treatment time, which would affect process costs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Par Pond water balance

    International Nuclear Information System (INIS)

    Hiergesell, R.A.; Dixon, K.L.

    1996-06-01

    A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs

  10. Orthodontic treatment stability predictors: A retrospective longitudinal study.

    Science.gov (United States)

    de Bernabé, Paloma González-Gil; Montiel-Company, José María; Paredes-Gallardo, Vanessa; Gandía-Franco, Jose Luis; Bellot-Arcís, Carlos

    2017-03-01

    To examine medium- to long-term orthodontic treatment stability and its possible association with certain variables. In a retrospective longitudinal study of 70 postretention patients, the Peer Assessment Rating (PAR) index was measured at the start (T1) and end (T2) of treatment and between 4 and 10 years afterwards (T3). The stability was considered absolute when the T2 and T3 values were identical and relative when the difference was within the ±5 range. Among the 70 patients, 65.8% were female and 34.2% were male. Their mean age was 14.5 years. The mean treatment length was 2.4 years. The mean retention phase was 3.3 years. The mean pre- and posttreatment PAR scores were 29.8 (T1) and 6.3 (T2). The mean T1-T2 difference was 23.6. The mean T2-T3 difference was -0.39. Within the study, 7.1% presented absolute stability and 68.6% presented relative stability. Lower anterior segment alignment and overbite were the most unstable occlusal features and tended to worsen. Fixed retainer (odds ratio [OR] 0.31; 95% confidence interval [CI] 0.10-0.98) as a protective factor and years without retention (OR 1.32; 95% CI 1.03-1.68) as a risk factor are predictor variables of instability in the case of lower anterior segment alignment. The PAR value at the end of treatment (OR 1.29; 95% CI 1.08-1.54) and extractions (OR 4.76; 95% CI 1.05-21.6) before treatment are predictors for midline instability.

  11. Radioactive and hazardous wastewater treatment and sludge stabilization by filtration

    International Nuclear Information System (INIS)

    Martin, H.L.; Pickett, J.B.; Langton, C.A.

    1991-01-01

    Concentrated effluents from batch discharges of spent process solutions are mixed with filter cake from treatment of the dilute effluents and stored in a large tank at the optimum high pH for hydroxide precipitation of heavy metals. Supernate is decanted from the storage tanks and mixed with the dilute effluents before treatment. A filtration and stabilization process has been developed to treat and stored sludge as well as the concentrated wastewater slurry as it is generated. A 94% waste volume reduction over conventional technology can be achieved. Furthermore, leachate from the solidified waste filter cake meets the EPA land disposal restrictions

  12. Nickel speciation in cement-stabilized/solidified metal treatment filtercakes

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Amitava, E-mail: reroy@lsu.edu [J. Bennett Johnston, Sr., Center for Advanced Microstructures and Devices, Louisiana State University, Baton Rouge, LA 70806, USA (United States); Stegemann, Julia A., E-mail: j.stegemann@ucl.ac.uk [Centre for Resource Efficiency & the Environment, Department of Civil, Environmental & Geomatic Engineering, University College London, Chadwick Building, Gower Street, London WC1E 6BT, UK (United Kingdom)

    2017-01-05

    Highlights: • XAS shows the same Ni speciation in untreated and stabilized/solidified filtercake. • Ni solubility is the same for untreated and stabilized/solidified filtercake. • Leaching is controlled by pH and physical encapsulation for all binders. - Abstract: Cement-based stabilization/solidification (S/S) is used to decrease environmental leaching of contaminants from industrial wastes. In this study, two industrial metal treatment filtercakes were characterized by X-ray diffractometry (XRD), thermogravimetric and differential thermogravimetric analysis (TG/DTG) and Fourier transform infrared (FTIR); speciation of nickel was examined by X-ray absorption (XAS) spectroscopy. Although the degree of carbonation and crystallinity of the two untreated filtercakes differed, α-nickel hydroxide was identified as the primary nickel-containing phase by XRD and nickel K edge XAS. XAS showed that the speciation of nickel in the filtercake was unaltered by treatment with any of five different S/S binder systems. Nickel leaching from the untreated filtercakes and all their stabilized/solidified products, as a function of pH in the acid neutralization capacity test, was essentially complete below pH ∼5, but was 3–4 orders of magnitude lower at pH 8–12. S/S does not respeciate nickel from metal treatment filtercakes and any reduction of nickel leaching by S/S is attributable to pH control and physical mechanisms only. pH-dependent leaching of Cr, Cu and Ni is similar for the wastes and s/s products, except that availability of Cr, Cu and Zn at decreased pH is reduced in matrices containing ground granulated blast furnace slag.

  13. Effect of a bentonite/soil mixture as a barrier for uranium ponds

    International Nuclear Information System (INIS)

    Osmanlioglu, A.E.

    2002-01-01

    Uranium mill tailings need safe management as they contain long-lived uranium and its daughters. Chemical treatment applied on these tailings to neutralize the acid solution and to stabilize the remaining radioactive elements. Then they are stored in ponds. These ponds are used for the accumulation of the solids and evaporation of the liquids. Sometimes the liquid returned to the plant for reuse. These applications are used to isolate the tailings from the environment. The purpose of this laboratory test is; initially to determine the effectiveness of bentonite/soil mixture as a barrier for uranium ponds. In this study, two experimental ponds equipped; with different two barriers in laboratory. Dimension of this container is; 120 cm in length, 100 cm in width and 100cm in depth. Sampling pipes were placed at different places of the container. First pond includes ordinary soil; second pond includes soil/bentonite mixture. Uranium mill tailing ponds were placed at the surfaces of these two systems. Uranium solution was prepared by using natural uranium ore. The solution was put into these ponds. These test carried out more than for 10 months. Passed solution was collected by sampling pipes and recorded. Amounts of passed solution were determined according to the location of discharge pipes. At the last stage of these tests, sampling from the different parts o the system has been carried out by small holes, which were opened from the surface by special sampling device. By this way, migration information about the upper parts of the sampling pipes has been received. Behaviour of uranium radionuclides and the effectiveness of the bentonite/soil mixture were experimentally determined. Bentonite/soil mixture layer has better ability to restrain the migration of uranium radionuclides. The performance of the ponds at the natural soil can be improved simply by mixing with bentonite during construction. Bentonite/soil mixture includes 5% bentonite, 95% ordinary soil in weight

  14. Simple intervention to reduce mosquito breeding in waste stabilisation ponds

    DEFF Research Database (Denmark)

    Ensink, Jeroen H J; Mukhtar, Muhammad; van der Hoek, Wim

    2007-01-01

    the control ponds had a significant number of positive samples. This suggests that a combination of simple low-cost interventions is a feasible environmental management strategy for vector control in WSP systems that are located in areas where medically important mosquitoes may breed in the shallow ponds.......Waste stabilisation ponds (WSP) are the preferred method for treatment of urban wastewater in low-income countries but, especially in arid regions, the pond systems can be important breeding sites for mosquitoes of medical importance. In a WSP system in Faisalabad, Pakistan, we assessed the impact...... of simple environmental interventions on mosquito occurrence and abundance. Reducing the amount of floating matter in the ponds, eliminating emergent vegetation and repairing cracks in the cement structure reduced the number of mosquito-positive samples in the intervention ponds to almost zero, whereas...

  15. Comportamento contrátil de barreiras selantes de solo estabilizado para base de lagoas de tratamento Contraction properties of liners produced with stabilized soil for stabelization pond base

    Directory of Open Access Journals (Sweden)

    Otoniel P. da Costa

    2007-02-01

    Full Text Available Barreiras selantes são dispositivos de proteção do subsolo em áreas de disposição de resíduos. No ambiente rural podem ser de grande utilidade para impermeabilização de fundo de lagoas de tratamento de resíduos porém sua construção deve ser simples e de baixo custo. Uma solução interessante é se usar, nesses casos, o solo local com pequena adição de cal ou cimento, de forma a atingir as propriedades de interesse. Um cuidado especial diz respeito ao comportamento contráctil desses materiais, que poderá comprometer seu uso. O presente trabalho apresenta resultados de ensaios de retração em laboratório em corpos-de-prova de solo arenoso, estabilizado com cal e cimento. As alterações na estrutura das misturas com o tempo foram verificadas com uso de microscopia eletrônica de varredura. O valor máximo de retração encontrado foi de 0,648% para corpos-de-prova com até quatorze dias de cura. Após vinte e oito dias de cura, os valores foram inferiores a 0,5% indicando materiais de baixa retração. As imagens microscópicas indicam que parcela significativa da retração ocorre até os sete dias de cura. Os resultados mostram que os materiais apresentam comportamento contráctil apropriado ao uso, como barreiras de proteção.Liners were proposed as subsoil contamination protection devices for waste disposal sites. In the rural environment, they can be used to construct pond bottoms for liquid waste treatment, but the construction needs to be quick and cheap. A good technical solution for these situations is the use of local soil compacted with low quantities of cement or lime, obtaining good properties for this purpose. These barriers need special care about their contraction behavior which may compromise its use. This work shows the results of contraction tests in sandy soil specimens and others stabilized with lime and with cement. Soil structure changes during cure time were checked using electronic scan microscopy

  16. Sludge accumulation in polishing ponds treating anaerobically digested wastewater.

    Science.gov (United States)

    Cavalcanti, P; van Haandel, A; Lettinga, G

    2002-01-01

    When ponds are used for wastewater treatment, settleable solids will form a steadily growing bottom sludge layer, which reduces their effective volume. Eventually this sludge must be removed to ensure that the pond maintains the required retention time to keep performing properly. The settleable solids may either be present in the influent or they are formed during the treatment as a result of algal flocculation. An experimental investigation was carried out to evaluate bottom sludge accumulation in a polishing pond used for treatment of UASB effluent. The mass and composition of the bottom sludge formed in a polishing pond was evaluated after the pilot scale pond had been in operation for 1 year and about 60 m3 of digested wastewater had been treated per m3 of pond. The bottom sludge mass represented a solids accumulation of 70 g per m3 of digested wastewater. About half of these solids were the result of settling of influent solids in the first part of the pond, while the other half was attributable to settling of algae, formed in the pond. It is concluded that the bottom sludge growth in a polishing pond is so low, that desludging during the useful life span of the pond will most likely not be necessary. This leads to the important conclusion that excess sludge discharge from UASB reactors (a major factor in operational costs) may be omitted, if a polishing pond is used for post-treatment. The bottom sludge had a high volatile solids concentration (58%) and the macronutrient fractions were also high (3.9% N and 1.1% P of the TSS mass). The bottom sludge was stable and could be dried directly without problems. The hygienic quality of the bottom sludge was very poor: about half the influent helminth eggs during one year of operation were found in the bottom sludge and the faecal coliform concentration was very high.

  17. Effects of riparian buffers on hydrology of northern seasonal ponds

    Science.gov (United States)

    Randall K. Kolka; Brian J. Palik; Daniel P. Tersteeg; James C. Bell

    2011-01-01

    Although seasonal ponds are common in northern, glaciated, forested landscapes, forest management guidelines are generally lacking for these systems. The objective of this study was to determine the effect of riparian buffer type on seasonal pond hydrology following harvest of the adjacent upland forest. A replicated block design consisting of four buffer treatments...

  18. The Belmont Valley integrated algae pond system in retrospect ...

    African Journals Online (AJOL)

    Integrated Algae Pond Systems (IAPS) are a derivation of the Oswald-designed Algal Integrated Wastewater Pond Systems (AIWPS®) and combine the use of anaerobic and aerobic bioprocesses to effect sewage treatment. IAPS technology was introduced to South Africa in 1996 and a pilot plant designed and ...

  19. PERFORMANCES OF TIGER SHRIMP CULTURE IN ENVIRONMENTALLY FRIENDLY PONDS

    Directory of Open Access Journals (Sweden)

    Taufik Ahmad

    2016-10-01

    Full Text Available Mangrove ecosystem plays an obvious role in maintaining the biological balance in the coastal environment where shrimp ponds are usually constructed. The removal of mangroves around shrimp ponds has frequently brought about harvest failure. The study evaluated the performance of tiger shrimp culture in ponds provided with water from a water body where there was mangrove vegetation (hereafter mangrove reservoir. Twelve ponds, each measuring 2,500 m2, were filled with seawater from the mangrove reservoir until the water depth of 100 cm and then stocked with 20-40 PL/m2. In the first six ponds, the bottom water was released into the reservoir when the water depth reached 140 cm and then the water depth was maintained at 100 cm. In the second six ponds, the water was released from the ponds until the water depth reached 60 cm and then refilled with reservoir water until a depth of 100 cm. Both treatment ponds received water from the reservoir which also received the wastewater. The feeds for the shrimps were broadcast into the ponds twice a day to meet the 3% shrimp biomass requirement, which adjusted every other week through sampling. The result showed that mangrove  vegetation is capable of removing excessive nutrients, up to 70% for NO3- N and NH4 +-N, reducing PO4 =-P fluctuation, and producing bioactive  compounds. In the second treatment ponds, shrimp mortality started to occur in day 28 and most died by day 54 after stocking due to white spot disease outbreak. Mass mortality took place 54 days after stocking in two out of six of the first treatment ponds.

  20. Cooling pond fog studies

    International Nuclear Information System (INIS)

    Hicks, B.B.

    1978-01-01

    The Fog Excess Water Index (FEWI) method of fog prediction has been verified by the use of data obtained at the Dresden cooling pond during 1976 and 1977 and by a reanalysis of observations made in conjunction with a study of cooling pond simulators during 1974. For applications in which the method is applied to measurements or estimates of bulk water temperature, a critical value of about 0.7 mb appears to be most appropriate. The present analyses confirm the earlier finding that wind speed plays little part in determining the susceptibility for fog generation

  1. Structure and dynamics of the phytoplankton community within a maturation pond in a semiarid region

    Directory of Open Access Journals (Sweden)

    E. A. Pastich

    Full Text Available Abstract In northeastern Brazil, stabilization ponds are very suitable for wastewater treatment because of the relative great land availability and environmental conditions (e.g., high temperature favorable for microorganism optimal development. However, blooms of potentially toxic cyanobacteria may affect the use of these treatment ponds due to resulting effluent poor quality. The objective of this study was to evaluate the dynamics of phytoplankton communities and the occurrence of cyanobacteria in a maturation pond located immediately after a series of two ponds. Temperature, dissolved oxygen, pH, BOD, N, and P were measured during a period of four months when samples were collected from the surface and the bottom of 7 sampling points distributed inside the pond. The phytoplankton of collected samples was also identified and classified using a conventional optical microscopy. Analysis of variance and Tukey test were used to evaluate the results. The three phytoplankton divisions found (Cyanophyta, Chlorophyta, and Euglenophyta did not change considerably through surface and bottom. However, they changed greatly over the sampled months; great dominance of Cyanophyta was found at April and October, while Chlorophyta dominated the lagoon in September. Low superficial organic loads (between 78 and 109 kg BOD.ha–1.d–1 and N:P ≤ 10 were the determinant factors that favored the predominance of Cyanophyta. The presence of two potentially toxic species of Cyanophyta, Oscillatoria sp. and Microcystis aeruginosa, indicates that caution is required when considering the final destination of treated effluent and suggests a need to assess the risks and benefits associated with the use of the treatment technology.

  2. Stability of anterior open-bite treatment with occlusal adjustment.

    Science.gov (United States)

    Janson, Guilherme; Crepaldi, Marcus Vinicius; Freitas, Karina Maria Salvatore; de Freitas, Marcos Roberto; Janson, Waldyr

    2010-07-01

    In this study, we aimed to evaluate the long-term stability of anterior open-bite treatment with occlusal adjustment and the dentinal sensitivity caused by this procedure in the long term. The sample comprised 17 open-bite patients who experienced relapse of the negative vertical overbite after orthodontic treatment and were retreated with occlusal adjustment. The cephalometric changes were evaluated on lateral cephalograms obtained before and after the occlusal adjustment and in the long term (mean, 3.4 years after occlusal adjustment). Dentinal sensitivity was also evaluated before the occlusal adjustment, and 1.35 months, 4.61 months, and 3.4 years later. The cephalometric statuses between the 3 evaluations were compared with analysis of variance (ANOVA) and Tukey tests. The percentages of clinically significant relapse were calculated. To compare dentinal sensitivity at the several stages, nonparametric Friedman and Wilcoxon tests were performed. Statistically significant relapse of anterior open bite occurred in 33.3% of the patients. Those who had the procedure before 21 years of age were most likely to experience relapse. Dentinal sensitivity remained within the normal range in the long term. Despite the statistically significant relapse of anterior open bite, clinically significant stability was found in 66.7% of the patients. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  3. Radiation Treatment for Recycling of Industrial Wastewater for Industrial Usage - Biological and Irradiation Treatment of Mix Industrial Wastewater in Flood Mitigation Pond at Prai Industrial Zones

    International Nuclear Information System (INIS)

    Bakar, Khomsaton Abu; Sharif, Jamaliah; Selambakkanu, Sarala; Ming, Ting Teo; Isnin, Natsha; Osman, Hasnul Nizam; Azmi, Khasmidatul Akma M.K; Dahlan, Khairul Zaman Hj Mohd; Yahya, Nasehir khan Em

    2012-01-01

    In this research, activated sludge system and E-Beam was used to treat mixed industrial waste water from mitigation pond A. The objectives are to study the effect of hydraulic retention time (HRT) in activated sludge and effect of absorbed dose, current and energy to the characteristic of mix industrial wastewater and Di(2-ethylhexyl) phthalate(DEHP) added in the wastewater. DEPH is a type of plasticizer and quantified by GC-MS. Microbe identification in activated sludge was also carried out in this study. At 48hrs HRT, percentage reduction for COD, color, suspended solid were 62.3%, 36.7% and 67.1% respectively. While at 24hrs HRT, COD, color and suspended solid were reduce by 26.0%, 14.9% and 61.3% respectively. Microbial analysis showed six bacteria present in the activated sludge based on 16SrRNA gene sequences. Mixed industrial wastewater was irradiated using electron beam at 1Mev, 5mA and 10mA in a batch system with 3, 6, 8,10 and 12kGy doses. COD, color and suspended solid reduced with the increasing of absorbed dose. Mixed industrial wastewater added with DEPH in the second batch was irradiated with dose up to 300kGy. Concentration of DEHP also reduced with increasing of dose and more effectively decreased in acidic and aerated condition. (author)

  4. Treatment efficiency of a wet detention pond combined with filters of crushed concrete and sand: a Danish full-scale study of stormwater.

    Science.gov (United States)

    Sønderup, Melanie J; Egemose, Sara; Bochdam, Timm; Flindt, Mogens R

    2015-12-01

    Traditional wet detention ponds and sand filters remove particles efficiently, whereas only a minor part of the dissolved and bioavailable load is removed. To improve the retention of dissolved substances, we tested crushed concrete as a filter material simultaneously with a traditional sand filter placed after an existing wet pond. The particulate fractions (particles, organic matter, phosphorus, and heavy metals) were removed efficiently in the pond and both filter materials, with the concrete filter often being best seen over a year. Dissolved heavy metals (lead (Pb), nickel (Ni), copper (Cu), chromium (Cr), and cadmium (Cd)) were largely retained, though a washout was observed from the pond (Ni and Cu), concrete filter (Cr), and sand filter (Ni) during the first month. The pond only retained total dissolved phosphorus (TDP) during summer. Crushed concrete and sand had a high (>70%) retention of TDP within the first months of operation, but the retention dropped in both filters due to a large oil load into the system (4 kg impermeable ha(-1) in 1 month). The poor retention might to some degree be due to mineralization processes turning particulate phosphorus (PP) into TDP. The massive oil load was retained efficiently (99.3%) in the pond and both filters, clearly illustrating that both filter materials were able to retain either oil or TDP. An additional pilot study showed that at residence times of 1 h, crushed concrete bound 90% TDP whereas sand only bound 22% TDP. Retention of TDP and PP decreased with shorter residence time in both materials, but fastest in sand.

  5. Characterisation of potential aquaculture pond effluents, and ...

    African Journals Online (AJOL)

    Conventional treatment of effluents from these small-scale, low-volume operations, which discharge relatively dilute effluents infrequently, might not be cost-effective. Keywords: aquaculture–environment interaction, earthen ponds, effluent characterisation, K-means clustering, t ilapia, water quality. African Journal of Aquatic ...

  6. Assessing fly ash treatment: Remediation and stabilization of heavy metals

    DEFF Research Database (Denmark)

    Lima, A.T.; Ottosen, Lisbeth M.; Ribeiro, Alexandra B.

    2012-01-01

    Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through the electrodialy......Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through...... the electrodialytic process (EDR) has been tried out before. The goal of removing heavy metals has always been the reuse of fly ash, for instance in agricultural fields (BEK). The best removal rates are here summarized and some new results have been added. MSW fly ashes are still too hazardous after treatment to even...... consider application to the soil. ST ash is the only residue that gets concentrations low enough to be reused, but its fertilizing value might be questioned. An alternative reuse for the three ashes is here preliminary tested, the combination of fly ash with mortar. Fly ashes have been substituted...

  7. Effect of climate change on stormwater runoff characteristics and treatment efficiencies of stormwater retention ponds; a case study from Denmark using TSS and Cu as indicator pollutants. SpringerPlus, 5:1984, 1-12

    DEFF Research Database (Denmark)

    Sharma, Anitha Kumari; Vezzaro, Luca; Birch, Heidi

    2016-01-01

    concentrations. Similar results are expected for other particle bound pollutants including metals and slowly biodegradable organic substances such as PAH. Acute toxicity impacts to downstream surface waters seem to be only slightly affected. A minor increase in yearly loads of sediments and particle......This study investigated the potential effect of climate changes on stormwater pollution runoff characteristics and the treatment efficiency of a stormwater retention pond in a 95 ha catchment in Denmark. An integrated dynamic stormwater runoff quality and treatment model was used to simulate two...

  8. Stability comparison of two different dentoalveolar expansion treatment protocols

    Directory of Open Access Journals (Sweden)

    Ezgi Atik

    Full Text Available ABSTRACT Objective: The aim of this study was to compare the longitudinal stability of the conventional straight-wire system after the use of a quad-helix appliance with Damon self-ligating system in patients with Class I malocclusion. Methods: 27 adolescent patients were evaluated at three different periods: pre-treatment (T1, post-treatment (T2 and three years post-treatment (T3. Group 1 included 12 patients (with a mean age of 14.65 year treated with Damon 3MX bracket system; and Group 2 included 15 patients (with a mean age of 14.8 year who underwent orthodontic treatment with Roth prescribed brackets after expansion with Quad-Helix appliance. Relapse was evaluated with dental cast examination and cephalometric radiograph tracings. Statistical analysis was performed with IBM-SPSS for Windows software, version 21 (SPSS Inc., Chicago, IL. A p-value smaller than 0.05 was considered statistically significant. Results: There were significant increases in all transverse dental and postero-anterior measurements (except for UL6-ML mm in Group 1 with active treatment. There was some significant relapse in the long-term in inter-canine width in both groups and in the inter-first premolar width in Group 2 (p< 0.05. Significant decrease in all frontal measurements from T2 to T3 was seen for both groups. Upper and lower incisors significantly proclined in T1-T2 (p<0.05, however no relapse was found for both groups. When two systems were compared, there was no significant difference for the long-term follow-up period. Conclusion: Conventional (quad-helix appliance with conventional brackets and Damon systems were found similar with regard to the long-term incisor positions and transverse dimension changes of maxillary arch.

  9. Lime application methods, water and bottom soil acidity in fresh water fish ponds

    Directory of Open Access Journals (Sweden)

    Queiroz Julio Ferraz de

    2004-01-01

    Full Text Available Although some methods for determining lime requirement of pond soils are available and commonly used, there is still no consensus on whether it is more effective to apply liming materials to the bottoms of empty ponds or to wait and apply them over the water surface after ponds are filled. There is also little information on how deep lime reacts in pond sediment over time, and whether the depth of reaction is different when liming materials are applied to the water or to the soil. Therefore, three techniques for treating fish ponds with agricultural limestone were evaluated in ponds with clayey soils at a commercial fish farm. Amounts of agricultural limestone equal to the lime requirement of bottom soils were applied to each of three ponds by: direct application over the pond water surface; spread uniformly over the bottom of the empty pond; spread uniformly over the bottom of the empty pond followed by tilling of the bottom. Effectiveness of agricultural limestone applications did not differ among treatment methods. Agricultural limestone also reacted quickly to increase total alkalinity and total hardness of pond water to acceptable concentrations within 2 weeks after application. The reaction of lime to increase soil pH was essentially complete after one to two months, and lime had no effect below a soil depth of 8 cm. Tilling of pond bottoms to incorporate liming materials is unnecessary, and tilling consumes time and is an expensive practice; filled ponds can be limed effectively.

  10. Toxigenic Vibrio cholerae O1 in vegetables and fish raised in wastewater irrigated fields and stabilization ponds during a non-cholera outbreak period in Morogoro, Tanzania: an environmental health study.

    Science.gov (United States)

    Hounmanou, Yaovi M G; Mdegela, Robinson H; Dougnon, Tamègnon V; Mhongole, Ofred J; Mayila, Edward S; Malakalinga, Joseph; Makingi, George; Dalsgaard, Anders

    2016-10-18

    Cholera, one of the world's deadliest infectious diseases, remains rampant and frequent in Tanzania and thus hinders existing control measures. The present study was undertaken to evaluate the occurrence of toxigenic Vibrio cholerae O1 in wastewater, fish and vegetables during a non-outbreak period in Morogoro, Tanzania. From October 2014 to February 2015, 60 wastewater samples, 60 fish samples from sewage stabilization ponds and 60 wastewater irrigated vegetable samples were collected. Samples were cultured for identification of V. cholerae using conventional bacteriological methods. Isolates were confirmed as V. cholerae by detection of the outer membrane protein gene (ompW) using polymerase chain reaction (PCR). Isolates were further tested for antibiotic susceptibility and presence of virulence genes including, cholera enterotoxin gene (ctx), the toxin co-regulated pilus gene (tcpA) and the haemolysin gene (hlyA). The prevalence of V. cholerae in wastewater, vegetables and fish was 36.7, 21.7 and 23.3 %, respectively. Two isolates from fish gills were V. cholerae O1 and tested positive for ctx and tcpA. One of these contained in addition the hlyA gene while five isolates from fish intestines tested positive for tcpA. All V. cholerae isolates were resistant to ampicillin, amoxicillin and some to tetracycline, but sensitive to gentamicin, chloramphenicol, and ciprofloxacin. Our results show that toxigenic and drug-resistant V. cholerae O1 species are present and persist in aquatic environments during a non-cholera outbreak period. This is of public health importance and shows that such environments may be important as reservoirs and in the transmission of V. cholerae O1.

  11. Pond dyes are Culex mosquito oviposition attractants

    Directory of Open Access Journals (Sweden)

    Natali Ortiz Perea

    2017-05-01

    Full Text Available Background British mosquito population distribution, abundance, species composition and potential for mosquito disease transmission are intimately linked to the physical environment. The presence of ponds and water storage can significantly increase the density of particular mosquito species in the garden. Culex pipiens is the mosquito most commonly found in UK gardens and a potential vector of West Nile Virus WNV, although the current risk of transmission is low. However any factors that significantly change the distribution and population of C. pipiens are likely to impact subsequent risk of disease transmission. Pond dyes are used to control algal growth and improve aesthetics of still water reflecting surrounding planting. However, it is well documented that females of some species of mosquito prefer to lay eggs in dark water and/or containers of different colours and we predict that dyed ponds will be attractive to Culex mosquitoes. Methods Black pond dye was used in oviposition choice tests using wild-caught gravid C. pipiens. Larvae from wild-caught C. pipiens were also reared in the pond dye to determine whether it had any impact on survival. An emergence trap caught any adults that emerged from the water. Water butts (80 L were positioned around university glasshouses and woodland and treated with black pond dye or left undyed. Weekly sampling over a six month period through summer and autumn was performed to quantified numbers of larvae and pupae in each treatment and habitat. Results Gravid female Culex mosquitoes preferred to lay eggs in dyed water. This was highly significant in tests conducted under laboratory conditions and in a semi-field choice test. Despite this, survivorship in black dyed water was significantly reduced compared to undyed water. Seasonal analysis of wild larval and pupal numbers in two habitats with and without dye showed no impact of dye but a significant impact of season and habitat. Mosquitoes were more

  12. Aquatic biodiversity in sedimentation ponds receiving road runoff - What are the key drivers?

    Science.gov (United States)

    Sun, Zhenhua; Brittain, John E; Sokolova, Ekaterina; Thygesen, Helene; Saltveit, Svein Jakob; Rauch, Sebastien; Meland, Sondre

    2018-01-01

    Recently, increased attention has been paid to biodiversity conservation provided by blue-green solutions such as engineered ponds that are primarily established for water treatment and flood control. However, little research has been done to analyse the factors that affect biodiversity in such ponds. The purpose of this study was to evaluate the influence of environmental factors on aquatic biodiversity, mainly macroinvertebrate communities, in road sedimentation ponds in order to provide a foundation for recommendations on aquatic biodiversity conservation. Multivariate statistical methods, including unconstrained and constrained analysis, were applied to examine the relationships between organisms and the water quality as well as physical factors (including plant cover). Stepwise multiple regressions indicated that the most important variables governing the variation in the biological community composition were pond size, average annual daily traffic, metals, chloride, distance to the closest pond from study pond, dissolved oxygen, hydrocarbons, and phosphorus. The presence of most taxa was positively correlated with pond size and negatively correlated with metals. Small ponds with high pollutant loadings were associated with a low diversity and dominated by a few pollution tolerant taxa such as oligochaetes. A comprehensive understanding of impacts of various environmental factors on aquatic biodiversity is important to effectively promote and conserve aquatic biodiversity in such sedimentation ponds. Our results indicate that road sedimentation ponds should be designed large enough, because large ponds are likely to provide a more heterogeneous habitat and thus contain a species rich fauna. In addition, larger ponds seem to be less contaminated due to dilution compared to smaller ponds, thereby maintaining a higher biodiversity. Finally, creating some additional ponds in the vicinity of the sedimentation ponds in areas with few water bodies would increase the

  13. Assessing fly ash treatment: Remediation and stabilization of heavy metals

    KAUST Repository

    Lima, A.T.

    2010-12-17

    Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through the electrodialytic process (EDR) has been tried out before. The goal of removing heavy metals has always been the reuse of fly ash, for instance in agricultural fields (BEK). The best removal rates are here summarized and some new results have been added. MSW fly ashes are still too hazardous after treatment to even consider application to the soil. ST ash is the only residue that gets concentrations low enough to be reused, but its fertilizing value might be questioned. An alternative reuse for the three ashes is here preliminary tested, the combination of fly ash with mortar. Fly ashes have been substituted by cement fraction or aggregate fraction. Surprisingly, better compressive strengths were obtained by replacing the aggregate fraction. CW ashes presented promising results for the substitution of aggregate in mortar and possibly in concrete. © 2010 Elsevier Ltd.

  14. Assessing fly ash treatment: remediation and stabilization of heavy metals.

    Science.gov (United States)

    Lima, A T; Ottosen, Lisbeth M; Ribeiro, Alexandra B

    2012-03-01

    Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through the electrodialytic process (EDR) has been tried out before. The goal of removing heavy metals has always been the reuse of fly ash, for instance in agricultural fields (BEK). The best removal rates are here summarized and some new results have been added. MSW fly ashes are still too hazardous after treatment to even consider application to the soil. ST ash is the only residue that gets concentrations low enough to be reused, but its fertilizing value might be questioned. An alternative reuse for the three ashes is here preliminary tested, the combination of fly ash with mortar. Fly ashes have been substituted by cement fraction or aggregate fraction. Surprisingly, better compressive strengths were obtained by replacing the aggregate fraction. CW ashes presented promising results for the substitution of aggregate in mortar and possibly in concrete. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Microbiology of solar salt ponds

    Science.gov (United States)

    Javor, B.

    1985-01-01

    Solar salt ponds are shallow ponds of brines that range in salinity from that of normal seawater (3.4 percent) through NaCl saturation. Some salterns evaporate brines to the potash stage of concentration (bitterns). All the brines (except the bitterns, which are devoid of life) harbor high concentrations of microorganisms. The high concentrations of microorganisms and their adaptation to life in the salt pond are discussed.

  16. Oxytetracycline Assay in Pond Sediment

    Directory of Open Access Journals (Sweden)

    L. Nepejchalová

    2008-01-01

    Full Text Available The fate of drug residues and their metabolites in the environment is relatively rarely investigated in the conditions of the Czech Republic, resulting in limited availability of scientific information. To demonstrate one example, we prepared a model study with medicated feedstuff containing oxytetracycline hydrochloride (OTC HCl, which was used in fish under normal conditions of use. The oxytetracycline (OTC contents were determined in the sediments of the pond where the fish were treated. The ELISA method was used for OTC detection and the HPLC method was used for final quantification of OTC. The increasing contents of OTC in sediment depended on the repeated treatment and excretion of OTC by the fish. The concentration on day 59 after the last administration was 1516 μg kg-1 OTC in the sediment, which indicates a long-term persistence of the substance in the environment.

  17. Avaliação de métodos espectrofotométricos para determinação de proteína em amostras de lagoas de estabilização Evaluation of spectrophotometric methods for protein determination in waste stabilization ponds sample

    Directory of Open Access Journals (Sweden)

    Adriana Cristina Poli Miwa

    2008-06-01

    Full Text Available Esta pesquisa teve como objetivo principal comparar cinco métodos espectrofotométricos para determinação de proteínas em amostras provenientes de estações de tratamento de efluentes sanitários. O intuito foi definir uma metodologia de aplicação rápida, fácil e confiável para este tipo de amostra. As lagoas de estabilização, como sistemas de tratamento biológico, têm como principais constituintes proteínas, carboidratos e lipídeos, mas também apresentam muitos compostos interferentes, como por exemplo, uréia, detergentes e compostos fenólicos, que podem prejudicar a quantificação de tais parâmetros. Os métodos analisados foram Lowry, Biureto, Bradford e Ácido bicinconínico. O método de Lowry mostrou-se mais adequado às características da amostra, com boa reprodutibilidade, reagente específico, custo moderado e ausência de substancias interferentes.This research had as main objective to compare five spectrophotometric methods for protein determination in samples proceeding from sanitary effluent of treatment plant. Intention was to define a methodology that is of fast and easy and reliable application for this type of sample. The stabilization ponds, as systems of biological treatment, have as main constituent proteins, carbohydrates and lipids, but also they present many interfering composites, for example, phenolic urea, detergents and composites, that can harm the quantification of such parameters. The analyzed methods had been Lowry, Biuret, Bradford and Acid bicinconinic. The method of Lowry revealed more adequate to the characteristics of the sample, with good reproducibility, specific reagent, moderate cost and absence of interfering substance.

  18. Report on the methylmercury situation in Par Pond. Final report

    International Nuclear Information System (INIS)

    Schindler, J.E.; Williams, D.J.; Alberts, J.J.

    1975-06-01

    Studies are reported on the methylation and accumulation of mercury in fish populations of the pond. Results showed that the majority of the mercury in the fish muscles was in the methyl mercury form. Very low concentrations of mercury were found in the pond sediments. Physiological methylation of the mercury could not be demonstrated by in vivo or in vitro techniques. Organic ligand methylation and reduction of the mercury was shown to be a possible mechanism to account for both the mercury distribution in the pond and the concentrations of methylmercury in the fish. Recommendations are made for remedial treatments to eliminate the mercury problem. (HLW)

  19. Treatment results and long-term stability of anterior open bite malocclusion.

    NARCIS (Netherlands)

    Remmers, D.; Hullenaar, B.W. van 't; Bronkhorst, E.M.; Berge, S.J.; Katsaros, C.

    2008-01-01

    OBJECTIVES: To evaluate treatment results and long-term stability of anterior open bite malocclusion and to identify predictive factors for both treatment results and their stability. DESIGN: Retrospective study. SETTING AND SAMPLE POPULATION: The Department of Orthodontics and Oral Biology at the

  20. Eficiência da interação biodigestor e lagoas de estabilização na remoção de poluentes em dejetos de suínos Efficiency of biodigester and stabilization pond interaction in removal of swine manure pollutants

    Directory of Open Access Journals (Sweden)

    Marcelo Vivan

    2010-03-01

    Full Text Available A suinocultura é considerada atividade de alto poder poluidor, face ao elevado número de contaminantes nos seus efluentes, maximizado com o modelo de criação intensiva. Com o objetivo de contribuir para a reversão deste quadro, o presente trabalho teve a finalidade de avaliar o desempenho de um sistema de tratamento composto de um biodigestor e lagoas de estabilização (lagoa anaeróbia, uma facultativa e duas lagoas de maturação ligadas em série alimentadas com lodo proveniente de uma estação de tratamento de dejetos de suínos. O sistema mostrou-se eficiente para estabilização do resíduo, principalmente da carga orgânica; no entanto, apresenta algumas limitações para redução de nutrientes, sobretudo do nitrogênio, pela contribuição de volatilização de amônia.Swine production is considered an activity with a high environmental impact, due to the presence of a high number of contaminants in the effluents that come out from the piggery. In this study the feasibility of a combined process biodigestor and stabilization ponds (anaerobic, facultative and maturation connected in sequence fed with sludge from a swine manure treatment unit was evaluated. The system showed itsetf as efficient in the removal of organic matter, however it presented some limitations in removing nutrients, especially nitrogen, mainly due to the contribution of volatilization of ammonia.

  1. Mood-stabilizing pharmacological treatment in bipolar disorders and risk of suicide

    DEFF Research Database (Denmark)

    Søndergård, Lars; Lopez, Ana Garcia; Andersen, Per Kragh

    2008-01-01

    OBJECTIVES: This study investigated the association between continued mood-stabilizing treatment (lithium and anticonvulsants) in bipolar disorder (BD) and the risk of suicide. METHODS: Using linkage of national registers, the association between continued mood-stabilizing treatment and suicide w...... similar reduction in the rate of suicide, the results suggest that treatment with lithium may have some superiority in relation to prevention of suicide.......OBJECTIVES: This study investigated the association between continued mood-stabilizing treatment (lithium and anticonvulsants) in bipolar disorder (BD) and the risk of suicide. METHODS: Using linkage of national registers, the association between continued mood-stabilizing treatment and suicide...... was investigated among all patients discharged nationwide from hospital psychiatry as an in- or outpatient in a period from 1995 to 2000 in Denmark with a diagnosis of BD. RESULTS: A total of 5,926 patients were included in the study and among these 51 patients committed suicide eventually during the study period...

  2. Mood-stabilizing pharmacological treatment in bipolar disorders and risk of suicide

    DEFF Research Database (Denmark)

    Søndergård, Lars; Lopez, A.G.; Andersen, Per Kragh

    2008-01-01

    Objectives: This study investigated the association between continued mood-stabilizing treatment (lithium and anticonvulsants) in bipolar disorder (BD) and the risk of suicide. Methods: Using linkage of national registers, the association between continued mood-stabilizing treatment and suicide w...... similar reduction in the rate of suicide, the results suggest that treatment with lithium may have some superiority in relation to prevention of suicide Udgivelsesdato: 2008......Objectives: This study investigated the association between continued mood-stabilizing treatment (lithium and anticonvulsants) in bipolar disorder (BD) and the risk of suicide. Methods: Using linkage of national registers, the association between continued mood-stabilizing treatment and suicide...... was investigated among all patients discharged nationwide from hospital psychiatry as an in- or outpatient in a period from 1995 to 2000 in Denmark with a diagnosis of BD. Results: A total of 5,926 patients were included in the study and among these 51 patients committed suicide eventually during the study period...

  3. Diffusion of single oxidation pond

    Directory of Open Access Journals (Sweden)

    Song Ruo-Yuan

    2016-01-01

    Full Text Available The hydraulic characteristic of an oxidation pond was studied by the tracer experiment, and an empirical formula of Peclet number was obtained, which can be well applied to the model of plug flow reactor with longitudinal diffusion.

  4. 120-D-1 (100-D) Ponds supplemental information to the Hanford Facility Contingency Plan. Revision 2

    International Nuclear Information System (INIS)

    Petersen, S.W.; Zoric, J.P.

    1997-06-01

    This document is a supplement to the Hanford Facility Contingency Plan and provides the unit-specific information needed to fully comply with the Washington Administrative Code 173-303 for contingency plans. The 100-D ponds are unlined surface impoundments that were mainly used to dispose of nondangerous wastewater, The ponds are designated as a single treatment, storage, and/or disposal unit because of potential corrosive characteristics of the wastewater. No waste is currently present at the 100-D Ponds

  5. Biogeochemical ecology of aquaculture ponds

    International Nuclear Information System (INIS)

    Weisburd, R.S.J.

    1988-01-01

    Two methods to determine rates of organic matter production and consumption were applied in shrimp aquaculture ponds. Several questions were posed: can net rates of organic matter production and consumption be determined accurately through application of dissolved inorganic carbon (DIC) mass balance in a pond with high advective through-put? Are organically loaded aquaculture ponds autotrophic? How do rates of organic production vary temporally? Are there diurnal changes in respiration rates? Four marine ponds in Hawaii have been evaluated for a 53 day period through the use of geochemical mass balances. All fluxes of DIC into and out of the ponds were considered. DIC was calculated from hourly pH measurements and weekly alkalinity measurements. Average uptake of DIC from the pond water, equivalent to net community production, revealed net autotrophy in all cases. Hourly and longer period variations in organic matter production rates were examined. The daily cycle dominated the variation in rates of net community production. Maximal rates of net community production were maintained for four to six hours starting in mid-morning. Respiration rates decreased rapidly during the night in two of the ponds and remained essentially constant in the others. A similar pattern of decreasing respiration at night was seen in freshwater shrimp ponds which were studied with incubations. A new method involving isotope dilution of 14 C-labeled DIC was used to measure respiration rates in light and dark bottles. This method is an inexpensive and convenient procedure which should also be useful in other environments. The incubations demonstrated that plankton respiration rates peak at or soon after solar noon and vary over the course of the day by about a factor of two

  6. 2101-M pond closure plan

    International Nuclear Information System (INIS)

    1993-06-01

    This document describes activities for the closure of a surface impoundment (2101-M Pond) at the Hanford Site. The 2101-H Pond was initially constructed in 1953 to serve as a drainage collection area for the 2101-H Building. (Until the Basalt Waste Isolation Project (BWIP) Laboratory was constructed in the 2101-M Building in 1979--1981, the only source contributing discharge to the pond was condensate water from the 2101-H Building heating, ventilation, and air conditioning (HVAC) system. The drains for the BWIP Laboratory rooms were plumbed into a 4-in., cast-iron, low-pressure drain pipe that carries waste water from the HVAC system to the pond. During the active life of the BWIP Laboratory, solutions of dissolved barium in groundwater samples were discharged to the 2101-M Pond via the laboratory drains. As a result of the discharges, a Part A permit application was initially submitted to the Washington State Department of Ecology (Ecology) in August 1986 which designates the 2101-M Pond as a surface impoundment

  7. Can terraced pond wetland systems improve urban watershed water quality?

    Science.gov (United States)

    Li, S.; Ho, M.; Flanagan, N. E.; Richardson, C. J.

    2017-12-01

    Properly built constructed wetlands are a more economic and efficient way of wastewater treatment compared with traditional methods, although their mechanisms are far from completely understood. As part of the Stream and Wetland Assessment Management Park (SWAMP), which is aimed to improve the water quality of downstream and thereby enhance watershed ecosystem services, a terraced three-pond wetland system was created near Duke University in 2014. This project is expected to promote the retention and settling of pollutants and sediment before runoffs enter downstream flow. The goal of this study is to examine: (1) whether a terraced pond wetland system improves water quality, during both baseline (low flow) and storm events (high flow), which increases pollutant inputs; and (2) how this system functions to remove pollutants, namely what components of this system (plant, soil or water) increase or decrease the level of pollutants. By analyzing a dataset consisting of more than four-year monthly samplings from Pond 1 (first pond in the system) and Pond 3 (last pond in the system), we found that the pond system has reduced total suspended solids (TSS) but only when elevated inputs occur. Dissolved oxygen (DO) is closely related to temperature and macrophytes growth; whereas acidity (pH), total nitrogen (TN), and total phosphorus (TP) did not show retention in the early stages of the system development. This system reaches its optimum for reducing TSS at the second pond, but the third pond has important effects on DO, pH, TN and TP. A monitoring in 2017 shows this pond system significantly reduces TSS while increasing dissolved oxygen and neutralizing pH after a storm event; although greater variations incurred within the system as time progresses after storm, overall retention function remained valid. Retention of the pollutants is primarily accomplished by the settling process, which occurs in stilled waterbody of the ponds and by the filtration of macrophytes. We

  8. Establishing Theoretical Stability and Treatment Integrity for Motivational Interviewing.

    Science.gov (United States)

    Atkinson, Cathy; Woods, Kevin

    2017-07-01

    There is increasing evidence claiming the effectiveness of motivational interviewing (MI) in promoting behavioural change. However, ongoing changes to MI theory and practice have implications for its transferability, accessibility and for the validity of previous findings. Lack of practice consistency may make its effectiveness difficult to evaluate. This paper explores the complexity of MI and issues in the development of evidence-based practice in delivery, before describing issues related to practitioner application. Theoretical and practice developments over the last 30 years are reviewed under the headings theory, practice and efficacy. Specifically, developments across the three editions of the core MI texts are examined. Findings from the literature suggest a lack of theoretical stability and practice integrity, with recent fundamental changes to the underpinning structure of MI. Issues relating to the transferability and acquisition of MI skills, consistency of delivery and mechanisms underlying change are discussed. The authors call for greater theoretical stability, more transparency over how developments are based on theoretical principles and empirical outcomes, and clearer guidance about how this informs practice development and delivery of MI.

  9. Anaerobic Treatment of Cane Sugar Effluent from Muhoroni Sugar ...

    African Journals Online (AJOL)

    It was therefore concluded that anaerobic treatment, particularly with pH control and seeding shows potential in first stage management of sugar mill wastewater. Keywords: cane sugar mill effluent, anaerobic treatment, batch reactor, waste stabilization ponds. Journal of Civil Engineering Research and Practice Vol.

  10. Comments on the asymptotic treatment of tokamak MHD-stability at large aspect ratio

    International Nuclear Information System (INIS)

    Rebhan, E.

    1980-01-01

    In the asymptotic treatment of tokamak MHD stability at small inverse aspect ratio epsilon, the special case of poloidal wave number m=0 has been treated improperly in the literature for both axisymmetric and non-axisymmetric modes. In axisymmetric stability, a contribution to the perturbational vacuum field is either omitted or cancelled. In a variational stability analysis this field contribution provides σ 2 W with a correction term proportional to (1nepsilon) -1 , which may change the asymptotic range of stability and improve agreement with numerical finite-aspect-ratio results. In non-axisymmetric stability, for the perturbational vacuum field of the m=0 modes, usually the wrong of two possible solutions is chosen. It is shown why in many cases this wrong choice has no consequences on the correctness of the stability results, and circumstances are pointed out under which consequences may arise. (author)

  11. Microtubule Stabilizing Agents as Potential Treatment for Alzheimer’s Disease and Related Neurodegenerative Tauopathies

    Science.gov (United States)

    Ballatore, Carlo; Brunden, Kurt R.; Huryn, Donna M.; Trojanowski, John Q.; Lee, Virginia M.-Y.; Smith, Amos B.

    2012-01-01

    The microtubule (MT)-associated protein tau, which is highly expressed in the axons of neurons, is an endogenous MT-stabilizing agent that plays an important role in the axonal transport. Loss of MT-stabilizing tau function, caused by misfolding, hyperphosphorylation and sequestration of tau into insoluble aggregates, leads to axonal transport deficits with neuropathological consequences. Several in vitro and preclinical in vivo studies have shown that MT-stabilizing drugs can be utilized to compensate for the loss of tau function and to maintain/restore an effective axonal transport. These findings indicate that MT-stabilizing compounds hold considerable promise for the treatment of Alzheimer disease and related tauopathies. The present article provides a synopsis of the key findings demonstrating the therapeutic potential of MT-stabilizing drugs in the context of neurodegenerative tauopathies, as well as an overview of the different classes of MT-stabilizing compounds. PMID:23020671

  12. Treatment efficiency in wastewater treatment plant of Hat Yai Municipality by quantitative removal of microbial indicators

    Directory of Open Access Journals (Sweden)

    Duangporn Kantachote

    2009-11-01

    Full Text Available The efficiency of treatment in a wastewater treatment plant of Hat Yai Municipality through stabilization ponds and constructed wetlands was monitored by using the bacterial indicators, total coliforms (TC, fecal coliforms (FC, Escherichia coli and fecal streptococci (FS, and photosynthetic microbes. The sequence of water flow in the wastewater treatment plant is as follows: primary or anaerobic pond (P, facultative pond (F, maturation pond (M, constructed wetlands (W1, W2 and W3, and an effluent storage pond (S for the treated wastewater. The wastewater treatment plant has an approximate area of 3,264,000 m2 (2,040 rai and its dry weather flow was running at only 40,000 m3/ day. There were 10 sampling times used for all the 7 ponds during July-October, 2006.Statistical analysis using a Two-Factorial Design model, indicated that pond types significantly affected temperature, dissolved oxygen (DO, and pH (p<0.05, whereas the time of sampling during the day had a significant effect (p<0.05 only on the temperature and light intensity available to the ponds. There were also significant different removal efficiencies of the different bacterial indicator groups tested (p<0.05. The overall performance of the wastewater treatment plant effectively removed TC, FC, E. coli, and FS as follows, 99.8%, 99.8%, 75.8% and 98.8%, respectively. The amounts of bacterial indicators, except for E. coli, showed a negative correlation with levels of light intensity and DO, whereas there was no correlation between the pH and the different indicator bacteria. There was a positive middle level correlation between pHand chlorophyll a.There were five different divisions of photosynthetic organisms detected throughout the plant as follows, Cyanophyta, Chlorophyta, Bacillariophyta, Euglenophyta, and Pyrrhophyta. The least diversity was found in the anaerobic pond (P as there were only 15 genera. Euglena, an indicator of dirty water, was detected only in this pond. The

  13. Macroinvertebrates of Par Pond and Pond B: Final report, January 1984-June 1985

    Energy Technology Data Exchange (ETDEWEB)

    Kondratieff, B.C.; Chimney, M.J.; Painter, W.B.

    1985-08-01

    This document reports on the Par Pond and Pond B macroinvertebrate sampling program from January 1984 through June 1985. It includes data on quantitative and qualitative benthic sampling, quantitative meroplankton sampling and quarterly diel sample. The basic objectives were to: (1) characterize the benthic and meroplankton macroinvertebrate communities of Par Pond and Pond B, with respect to taxonomic composition and diversity, density and relative abundance of functional feeding groups; (2) assess the impact of thermal discharges on the macroinvertebrate community of Par Pond; (3) assess the impact and significance of entrainment losses of macroinvertebrate meroplankton from Par Pond; and (4) compare Par Pond macroninvertebrate communities with those in Pond B.

  14. Global stability of two models with incomplete treatment for tuberculosis

    International Nuclear Information System (INIS)

    Yang Yali; Li Jianquan; Ma Zhien; Liu Luju

    2010-01-01

    Research highlights: → Two tuberculosis models with incomplete treatment. → Intuitive epidemiological interpretations for the basic reproduction numbers. → Global dynamics of the two models. → Strategies to control the spread of tuberculosis. - Abstract: Two tuberculosis (TB) models with incomplete treatment are investigated. It is assumed that the treated individuals may enter either the latent compartment due to the remainder of Mycobacterium tuberculosis or the infectious compartment due to the treatment failure. The first model is a simple one with treatment failure reflecting the current TB treatment fact in most countries with high tuberculosis incidence. The second model refines the simple one by dividing the latent compartment into slow and fast two kinds of progresses. This improvement can be used to describe the case that the latent TB individuals have been infected with some other chronic diseases (such as HIV and diabetes) which may weaken the immunity of infected individuals and shorten the latent period of TB. Both of the two models assume mass action incidence and exponential distributions of transfers between different compartments. The basic reproduction numbers of the two models are derived and their intuitive epidemiological interpretations are given. The global dynamics of two models are all proved by using Liapunov functions. At last, some strategies to control the spread of tuberculosis are discussed.

  15. Global stability of two models with incomplete treatment for tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yali, E-mail: yylhgr@126.co [Department of Applied Mathematics, Xi' an Jiaotong University, Xi' an 710049 (China) and Department of Applied Mathematics and Physics, Air Force Engineering University, Xi' an 710051 (China); Li Jianquan, E-mail: jianq_li@263.ne [Department of Applied Mathematics and Physics, Air Force Engineering University, Xi' an 710051 (China); Ma Zhien, E-mail: zhma@mail.xjtu.edu.c [Department of Applied Mathematics, Xi' an Jiaotong University, Xi' an 710049 (China); Liu Luju, E-mail: dahai20401095@yahoo.com.c [Department of Mathematics, Henan University of Science and Technology, Luoyang 471003 (China)

    2010-12-15

    Research highlights: Two tuberculosis models with incomplete treatment. Intuitive epidemiological interpretations for the basic reproduction numbers. Global dynamics of the two models. Strategies to control the spread of tuberculosis. - Abstract: Two tuberculosis (TB) models with incomplete treatment are investigated. It is assumed that the treated individuals may enter either the latent compartment due to the remainder of Mycobacterium tuberculosis or the infectious compartment due to the treatment failure. The first model is a simple one with treatment failure reflecting the current TB treatment fact in most countries with high tuberculosis incidence. The second model refines the simple one by dividing the latent compartment into slow and fast two kinds of progresses. This improvement can be used to describe the case that the latent TB individuals have been infected with some other chronic diseases (such as HIV and diabetes) which may weaken the immunity of infected individuals and shorten the latent period of TB. Both of the two models assume mass action incidence and exponential distributions of transfers between different compartments. The basic reproduction numbers of the two models are derived and their intuitive epidemiological interpretations are given. The global dynamics of two models are all proved by using Liapunov functions. At last, some strategies to control the spread of tuberculosis are discussed.

  16. Blogging from North Pond

    Science.gov (United States)

    Marziali, C. G.; Edwards, K. J.

    2009-12-01

    Sea going research expeditions provide an ideal opportunity for outreach through blogs: the finite duration limits the author's commitment; scientists are usually in a remote location with fewer distractions; and fieldwork is visual and interesting to describe. Over four weeks this winter, Katrina Edwards of USC authored a blog about her deep-sea drilling expedition to North Pond, a depression in the ocean crust in the mid-Atlantic. She emailed daily dispatches and photos to USC Media Relations, which maintained a (still accessible) blog. Written for the general public, the blog quickly attracted interest from lay readers as well as from media organizations. Scientific American carried the blog on its web site, and the National Science Foundation linked to it in its "Science 360" electronic news digest. The blog also led to a Q&A with Edwards in the widely-read "Behind the Scenes" feature of LiveScience. Interest from science bloggers and National Geographic towards the end suggests that the blog could have expanded its reach given more time: expeditions lasting between six weeks and three months, such as occur during ocean drilling expeditions, would appear to be ideal candidates for a blog. Most importantly, the blog educated readers about the importance to planetary life of what Edwards calls the "intraterrestrials": the countless microbes that inhabit the oceanic crust and influence major chemical and biological cycles. Considering that the subjects of the expedition were invisible critters in a pitch-dark place, the blog shows what can be accomplished by scientists and institutions committed to public outreach.

  17. Linking Low-Level Stable Isotope Fractionation to Expression of the Cytochrome P450 Monooxygenase-Encoding ethB Gene for Elucidation of Methyl tert-Butyl Ether Biodegradation in Aerated Treatment Pond Systems▿ †

    Science.gov (United States)

    Jechalke, Sven; Rosell, Mònica; Martínez-Lavanchy, Paula M.; Pérez-Leiva, Paola; Rohwerder, Thore; Vogt, Carsten; Richnow, Hans H.

    2011-01-01

    Multidimensional compound-specific stable isotope analysis (CSIA) was applied in combination with RNA-based molecular tools to characterize methyl tertiary (tert-) butyl ether (MTBE) degradation mechanisms occurring in biofilms in an aerated treatment pond used for remediation of MTBE-contaminated groundwater. The main pathway for MTBE oxidation was elucidated by linking the low-level stable isotope fractionation (mean carbon isotopic enrichment factor [ɛC] of −0.37‰ ± 0.05‰ and no significant hydrogen isotopic enrichment factor [ɛH]) observed in microcosm experiments to expression of the ethB gene encoding a cytochrome P450 monooxygenase able to catalyze the oxidation of MTBE in biofilm samples both from the microcosms and directly from the ponds. 16S rRNA-specific primers revealed the presence of a sequence 100% identical to that of Methylibium petroleiphilum PM1, a well-characterized MTBE degrader. However, neither expression of the mdpA genes encoding the alkane hydroxylase-like enzyme responsible for MTBE oxidation in this strain nor the related MTBE isotope fractionation pattern produced by PM1 could be detected, suggesting that this enzyme was not active in this system. Additionally, observed low inverse fractionation of carbon (ɛC of +0.11‰ ± 0.03‰) and low fractionation of hydrogen (ɛH of −5‰ ± 1‰) in laboratory experiments simulating MTBE stripping from an open surface water body suggest that the application of CSIA in field investigations to detect biodegradation may lead to false-negative results when volatilization effects coincide with the activity of low-fractionating enzymes. As shown in this study, complementary examination of expression of specific catabolic genes can be used as additional direct evidence for microbial degradation activity and may overcome this problem. PMID:21148686

  18. Evaluation of relocation of unionid mussels into artificial ponds

    Science.gov (United States)

    Newton, T.J.; Monroe, E.M.; Kenyon, R.; Gutreuter, S.; Welke, K.I.; Thiel, P.A.

    2001-01-01

    Relocation of unionid mussels into refuges (e.g., hatchery ponds) has been suggested as a management tool to protect these animals from the threat of zebra mussel (Dreissena polymorpha) invasion. To evaluate the efficacy of relocation, we experimentally relocated 768 mussels, representing 5 species (Leptodea fragilis, Obliquaria reflexa, Fusconaia flava, Amblema plicata, and Quadrula quadrula) into an earthen pond at a National Fish Hatchery or back into the river. In both locations, mussels were placed into 1 of 4 treatments (mesh bags, corrals, and buried or suspended substrate-filled trays). Mussels were examined annually for survival, growth (shell length and wet mass), and physiological condition (glycogen concentration in foot and mantle and tissue condition index) for 36 mo in the pond or 40 mo in the river. We observed significant differences in mortality rates between locations (mortality was 4 times greater in the pond than in the river), among treatments (lowest mortality in the suspended trays), and among species (lower mortality in the amblemines than lamp-silines). Overall survival in both locations averaged 80% the 1st year; survival in the pond decreased dramatically after that. Although length and weight varied between locations and over time, these changes were small, suggesting that their utility as short-term measures of well being in long-lived unionids is questionable. Mussels relocated to the pond were in poor physiological condition relative to those in the river, but the magnitude of these differences was small compared to the inherent variability in physiological condition of reference mussels. These data suggest that relocation of unionids into artificial ponds is a high-risk conservation strategy; alternatives such as introduction of infected host fish, identification of mussel beds at greatest risk from zebra mussels, and a critical, large-scale assessment of the factors contributing to their decline should be explored.

  19. Effects of heat treatment on density, dimensional stability and color ...

    African Journals Online (AJOL)

    The purpose of this study was to evaluate the effect of heat treatment on some physical properties and color change of Pinus nigra wood which has high industrial use potential and large growing stocks in Turkey. Wood samples which comprised the material of the study were obtained from an industrial plant. Samples were ...

  20. Treatment of waste using a hybrid gas- water stabilized torch

    Czech Academy of Sciences Publication Activity Database

    Van Oost, G.; Hrabovský, Milan; Kopecký, Vladimír; Konrád, Miloš; Hlína, Michal; Kavka, Tetyana; Beeckman, E.; Verstraeten, J.

    2005-01-01

    Roč. 5, č. 1 (2005), s. 7-12. ISBN 4-9900642-4-8 R&D Projects: GA ČR GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * pyrolysis * waste treatment Subject RIV: BL - Plasma and Gas Discharge Physics

  1. Dewatering and RCRA partial closure action on solar evaporation ponds, Rocky Flats Plant, Golden, Colorado

    International Nuclear Information System (INIS)

    1991-06-01

    The Department of Energy (DOE) has prepared an Environmental Assessment (DOE/EA-0487) on its proposal to partially close five solar evaporation ponds at the Rocky Flats Plant (RFP) pursuant to the requirements of the Resource Conservation and Recovery Act (RCRA). This proposal would be known as a RCRA partial closure and would be accomplished by dewatering the ponds, where necessary, and converting any remaining sludge or evaporator concentrate to a solid wasteform (pondcrete and saltcrete). The pond sites would be stabilized to prevent erosion or other disturbance to the soil and to prevent infiltration of rain or snowmelt. The solid wasteform would be transported offsite for disposal. The five solar ponds (designated 207-A, 207-B (north, center, and south), and 207-C), are the only solar evaporation ponds that exist at the RFP. A finding of no significant impact is included

  2. Endovascular treatment of intracranial aneurysms with bioactive Cerecyte coils: effects on treatment stability

    International Nuclear Information System (INIS)

    Geyik, Serdar; Yavuz, Kivilcim; Ergun, Onur; Koc, Osman; Cekirge, Saruhan; Saatci, Isil

    2008-01-01

    The Cerecyte coils were developed to improve long-term stability of embolized cerebral aneurysms by producing an increased fibrous reaction over the neck of the aneurysms. We report our preliminary clinical experience with mid-term follow-up. Seventy-eight consecutive patients with 84 intracranial aneurysms treated exclusively with Cerecyte coils were included in this study. Forty-eight aneurysms were ruptured and 36 were incidental. Twenty-two aneurysms were small with ( 25 mm). The embolization technique was the same with that in standard bare coiling. Immediate post-procedure angiography demonstrated complete aneurysm occlusion in 69%, neck remnant in 29.8% and incomplete occlusion in 1.2%. Follow-up angiography was obtained in 80 aneurysms in a period of time ranging from 6 months to 2 years. The overall recanalization rate was 11.3%, and the re-treatment rate was 6.3%; in the subgroup analysis, recanalization rates were 4.5% in S/S; 9.8% in S/W; and 33.3% in large aneurysms. The only giant aneurysm also showed recanalization. Procedure-related morbidity and mortality rates were 2.6% and 1.3%, respectively. Our midterm results showed a relatively low rate of recurrence compared to those reported for platinum coils with morbidity and mortality rates comparable to those with standard bare platinum coils. The efficacy of Cerecyte coils in the long term will be specifically addressed by the ongoing randomized Cerecyte coil trial. (orig.)

  3. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  4. Performance evaluation of pumping systems used in commercial-scale, split-pond aquaculture

    Science.gov (United States)

    Split-pond aquaculture systems have been adopted widely by United States catfish farmers as a way to improve production performance. The split-pond consists of a fish-culture basin that is connected to a waste-treatment lagoon by two water conveyance structures. Water is circulated between the two b...

  5. 216-B-3 expansion ponds closure plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

    This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA.

  6. Treatment method for stabilization of radioactive exchange resin

    International Nuclear Information System (INIS)

    Hideo, Oni; Takashi, Miyake; Hitoshi, Miyamoto; Toshio, Funakoshi; Yuzo, Inagaki.

    1988-01-01

    This is a method for eluting radioactive nuclides from a radioactive ion exchange resin in which it has been absorbed. First, the Cs in this resin is extracted using a neutral salt solution which contains Na + . The Cs that has been transferred to the neutral salt solution is absorbed and expelled by inorganic ion exchangers. Then the Co, Fe, Mn and Sr in said resin are eluted using an acidic solution; the Co, Fe, Mn and Sr that have been transferred to the acidic solution are separated from that solution by means of a diffusion dialysis vat. This process is a unique characteristic of this ion exchange resin treatment method. 1 fig

  7. Master plan for remediation of the Sillamaee tailings pond and technical design project

    International Nuclear Information System (INIS)

    Kaasik, T.

    2000-01-01

    Remediation of the Sillamaee radioactive tailings pond is a priority in the Estonian National Environmental Plan. The Sillamaee plant has processed metal ores by hydrometallurgical methods since 1946. Processing continued until 1990, but in the 1970s, production of rare earths and rare metals was introduced and continues today at a smaller scale. The tailings pond contains residues from these operations. The environmental problems associated with the tailings pond are the stability of the dam and the release of contaminants. In order to deal with these two issues effectively, a master plan was drawn up. The master plan covers the period from 1997 to 2008 and was compiled with the cooperation of the Silmet Group and the Sillamaee International Expert Reference Group (SIERG). The master plan sets up a systematic approach for the overall tailings pond remediation, including drying its interior, reshaping and covering the surface, minimizing water flow through the tailings, and ensuring long-term dam stability

  8. Comparison of simple, small, full-scale sewage treatment systems in Brazil: UASB-maturation ponds-coarse filter; UASB-horizontal subsurface-flow wetland; vertical-flow wetland (first stage of French system).

    Science.gov (United States)

    von Sperling, M

    2015-01-01

    This paper presents a comparison between three simple sewage treatment lines involving natural processes: (a) upflow anaerobic sludge blanket (UASB) reactor-three maturation ponds in series-coarse rock filter; (b) UASB reactor-horizontal subsurface-flow constructed wetland; and (c) vertical-flow constructed wetlands treating raw sewage (first stage of the French system). The evaluation was based on several years of practical experience with three small full-scale plants receiving the same influent wastewater (population equivalents of 220, 60 and 100 inhabitants) in the city of Belo Horizonte, Brazil. The comparison included interpretation of concentrations and removal efficiencies based on monitoring data (organic matter, solids, nitrogen, phosphorus, coliforms and helminth eggs), together with an evaluation of practical aspects, such as land and volume requirements, sludge production and handling, plant management, clogging and others. Based on an integrated evaluation of all aspects involved, it is worth emphasizing that each system has its own specificities, and no generalization can be made on the best option. The overall conclusion is that the three lines are suitable for sewage treatment in small communities in warm-climate regions.

  9. Par Pond Fish, Water, and Sediment Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

  10. Par Pond Fish, Water, and Sediment Chemistry

    International Nuclear Information System (INIS)

    Paller, M.H.; Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond

  11. Remediation of the Sillamae Radioactive Tailings Pond, Estonia

    International Nuclear Information System (INIS)

    Barnekow, U.; Jaaksoo, R.; Kaasik, T.

    2011-01-01

    The paper presents experiences gained and progress achieved during the ongoing Sillamaee Radioactive Tailings Pond Remediation Project. The Sillamaee tailings pond covering ca. 50 ha is located next to the shoreline of the Baltic Sea near Sillamaee town in Estonia. Tailings disposal included mill tailings from uranium ore processing (1953-1977), enriched uranium refining (1977- 1990), from rare earth elements processing (since 1970; tailings disposal ended 2003), black shale processing (1948-1953) and liquid oil-shale ashes from the local power plant. Initial environmental and geotechnical investigations identified insufficient safety of the tailings pond for radiological, environmental and geotechnical reasons. Contaminated seepage was entering the Baltic Sea. The 25 m high northern tailings dam was affected by marine erosion and the stability of the dam was found to be insufficient. Therefore the multi-national Sillamaee Radioactive Tailings Pond Remediation Programme was launched in 1998 jointly financed by North European Countries (NEFCO), EU and Estonia. The remediation project included the following crucial remediation steps: Drillings and samplings including geotechnical, (hydro-)geological and environmental investigations (2000-2001); relocation of mine wastes and contaminated soils from the surrounding area onto the tailings pond for interim covering (2000-2003); initial stabilization measures (2001-2003) including a 1080 m long shore protection embankment along the shoreline of the Baltic Sea, a 720 m long pile grillage for stabilizing the northern dam including two rows of 15 m or 18 m deep continuous flight auger piles, a 580 m long and 12-18 m deep cut-off wall, a deep gravel-filled drainage ditch (520 m, up to 12 m deep) and a deep drainage trench. Reshaping of the dams with respect to long term dam stability and contouring of the pond area with respect to long term settlement portions lasted from 2003 till 2004 building up a ridge-type surface

  12. Mathematical Analysis for the Optimization of a Design in a Facultative Pond: Indicator Organism and Organic Matter

    Directory of Open Access Journals (Sweden)

    Facundo Cortés Martínez

    2014-01-01

    Full Text Available Stabilization ponds are easy to operate and their maintenance is simple. Treatment is carried out naturally and they are recommended in developing countries. The main disadvantage of these systems is the large land area they occupy. The aim of this study was to perform an optimization in the design and cost of a facultative pond, considering a mathematical analysis of the traditional methodology to determine the model constraints (fecal coliforms and organic matter. Matlab optimization toolbox was used for nonlinear programming. A facultative pond with the traditional method was designed and then the optimization system was applied. Both analyses meet the treated water quality requirements for the discharge to the receiving bodies. The results show a reduction of hydraulic retention time by 4.82 days, and a decrease in the area of 17.9 percent over the traditional method. A sensitivity analysis of the mathematical model is included. It is recommended to realize a full-scale study in order to verify the results of the optimization.

  13. The Belmont Valley integrated algae pond system in retrospect

    African Journals Online (AJOL)

    2013-03-26

    Mar 26, 2013 ... (MP) or by filtration (e.g. slow sand filter). Maturation ponds hold secondary treated effluent ... passive bioprocess that can be used to remediate, in addition to domestic sewage, brewery effluent, food ... IAPS is an operational, passive, sequential, sewage treatment facility that functions virtually in perpetuity ...

  14. Comprehensive stabilization mechanism of electron-beam irradiated polyacrylonitrile fibers to shorten the conventional thermal treatment

    Science.gov (United States)

    Park, Sejoon; Yoo, Seung Hwa; Kang, Ha Ri; Jo, Seong Mu; Joh, Han-Ik; Lee, Sungho

    2016-01-01

    An electron beam was irradiated on polyacrylonitrile (PAN) fibers prior to thermal stabilization. The electron-beam irradiation effectively shortened the thermal stabilization process by one fourth compared with the conventional thermal stabilization process. A comprehensive mechanistic study was conducted regarding this shortening of the thermal stabilization by electron-beam irradiation. Various species of chain radicals were produced in PAN fibers by electron-beam irradiation and existed for a relatively long duration, as observed by electron spin resonance spectroscopy. Subsequently, these radicals were gradually oxidized to peroxy radicals in the presence of oxygen under storage or heating. We found that these peroxy radicals (CO) enabled such an effective shortcut of thermal stabilization by acting as intermolecular cross-linking and partial aromatization points in the low temperature range (100–130 °C) and as earlier initiation seeds of successive cyclization reactions in the next temperature range (>130–140 °C) of thermal stabilization. Finally, even at a low irradiation dose (200 kGy), followed by a short heat treatment (230 °C for 30 min), the PAN fibers were sufficiently stabilized to produce carbon fibers with tensile strength and modulus of 2.3 and 216 GPa, respectively, after carbonization. PMID:27349719

  15. Comprehensive stabilization mechanism of electron-beam irradiated polyacrylonitrile fibers to shorten the conventional thermal treatment

    Science.gov (United States)

    Park, Sejoon; Yoo, Seung Hwa; Kang, Ha Ri; Jo, Seong Mu; Joh, Han-Ik; Lee, Sungho

    2016-06-01

    An electron beam was irradiated on polyacrylonitrile (PAN) fibers prior to thermal stabilization. The electron-beam irradiation effectively shortened the thermal stabilization process by one fourth compared with the conventional thermal stabilization process. A comprehensive mechanistic study was conducted regarding this shortening of the thermal stabilization by electron-beam irradiation. Various species of chain radicals were produced in PAN fibers by electron-beam irradiation and existed for a relatively long duration, as observed by electron spin resonance spectroscopy. Subsequently, these radicals were gradually oxidized to peroxy radicals in the presence of oxygen under storage or heating. We found that these peroxy radicals (CO) enabled such an effective shortcut of thermal stabilization by acting as intermolecular cross-linking and partial aromatization points in the low temperature range (100-130 °C) and as earlier initiation seeds of successive cyclization reactions in the next temperature range (>130-140 °C) of thermal stabilization. Finally, even at a low irradiation dose (200 kGy), followed by a short heat treatment (230 °C for 30 min), the PAN fibers were sufficiently stabilized to produce carbon fibers with tensile strength and modulus of 2.3 and 216 GPa, respectively, after carbonization.

  16. Influence of fiber treatment on dimensional stabilities of rattan waste composite boards

    Science.gov (United States)

    Zuraida, A.; Insyirah, Y.; Maisarah, T.; Zahurin, H.

    2018-01-01

    The main drawback of using natural fibers in composite boards is its hydrophilic properties which absorb a high volume of moisture. This results in low dimensional stability of the produced composite boards. Hence, the purpose of this study is to investigate the effects of fibers’ treatment processes of the rattan waste fibers on the dimensional stabilities of composite boards. The collected fibers underwent two types of retting processes, namely a water treatment and alkaline treatment retting processes; where the fibers were soaked in water and a 1% sodium hydroxide (NaOH) solution, respectively. The fibers were dried and mixed with poly(lactic) acid (PLA) pellets with ratio of 30% fibers: 70% matrix; before being fabricated into composite boards via a hot-pressing process and were labelled as RF/PLA, WRF/PLA, CRF/PLA for untreated rattan, rattan treated by water retting, rattan treated by chemical retting, respectively. The produced composite boards were cut and soaked in water for 24 hours for dimensional stability in terms of water absorption and thickness swelling tests. The results showed that WRF/PLA has the lowest water absorption (3.2%), and the CRF/PLA had the highest water absorption (23.2%). The thickness swelling showed a similar trend as water absorption. The presence of void contents and fibers damaged the insides of the boards, which contributed to low dimensional stabilities of the composite boards. It can be concluded that water retting facilitated in improving dimensional stability of the produced composite board.

  17. Wastewater Sludge Stabilization Using Lime A Case Study of West Ahwaz Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Mehdi Farzadkia

    2009-01-01

    Full Text Available Lime stabilization is a chemical method used for wastewater sludge stabilization. It is capable of decreasing large quantities of pathogens and of preventing microbial degradation of sludge organic materials. The main objective of the present experimental research was to investigate stabilization of the sludge from west Ahwaz wastewater treatment plant by lime addition and to control if the microbial quality of this sludge conforms to the USEPA standards for sludge reuse and safe disposal. The study was carried out on a pilot scale in 5 stages over a period of 12 months (July 2005 to June 2006 at west Ahwaz wastewater treatment plant laboratory using raw sludge. For the purposes of this study, a 30-liter reactor was commissioned and loaded with sludge and appropriate quantities of hydrated lime were added based on the solid waste percent. The parameters used to determine stabilization efficiency were pH, Total Coliform, Fecal Coliform, and parasite eggs. The results showed that lime addition at a ratio of 265g Ca(OH2/kg. ds was the optimum level for sludge stabilization in westAhwazwastewater treatment plant, which is acceptable from both economic and technical viewpoints. The method is capable of achieving class B but never satisfied class A of USEPA standards.

  18. Introducing Water-Treatment Subjects into Chemical Engineering Education.

    Science.gov (United States)

    Caceres, L.; And Others

    1992-01-01

    Proposes that inclusion of waste water treatment subjects within the chemical engineering curriculum can provide students with direct access to environmental issues from both a biotechnological and an ethical perspective. The descriptive details of water recycling at a copper plant and waste water stabilization ponds exemplify this approach from…

  19. The Effects of pH and Heat Treatment Processing on the Stability of ...

    African Journals Online (AJOL)

    This study was carried out to investigate the effects of pH and heat treatment processing on stability and natural food colours used in dairy products. A repeated laboratory experiment was conducted in which loss of colour intensity or change in shade of natural food colours used in acid and nearly neutral dairy products at ...

  20. [Membrane-stabilizing preparations in the treatment of patients with heart rhythm disorders of different etiologies].

    Science.gov (United States)

    Vizir, A D; Grigor'eva, Z E; Stepanova, I V; Vizir, V A

    1991-10-01

    Data are reported of a study of the efficacy of membrane-stabilizing antiarrhythmic agents--ethmosin, ethacisin, allapinin. The latter was used in the treatment of 85 patients with arrhythmias of different etiology and proved more effective as compared with ethmosin and ethacisin. In ventricular extrasystole the effect was favourable in 86%, in supraventricular--in 70% of patients.

  1. Stability of Comorbid Psychiatric Diagnosis among Youths in Treatment and Aftercare for Alcohol Use Disorders

    Science.gov (United States)

    Hawke, Josephine M.; Kaminer, Yifrah; Burke, Rebecca; Burleson, Joseph A.

    2008-01-01

    Objectives: To examine the stability of comorbid psychiatric diagnoses among a sample of 50 adolescents in cognitive-behaviorally-based treatment for alcohol and other substance use disorders (AOSUD). Methods: A standardized psychiatric interview was administered at baseline and 12 month later to obtain current comorbid psychiatric disorders. Chi…

  2. Marital stability and repartnering: infertility-related stress trajectories of unsuccessful fertility treatment.

    Science.gov (United States)

    Martins, Mariana V; Costa, Patrício; Peterson, Brennan D; Costa, Maria E; Schmidt, Lone

    2014-12-01

    To compare the trajectories of infertility-related stress between patients who remain in the same relationship and patients who repartner. Longitudinal cohort study using latent growth modeling. Fertility centers. Childless men and women evaluated before starting a new cycle of fertility treatment and observed for a 5-year period of unsuccessful treatments. None. Marital stability and infertility-related stress. The majority of patients (86%) remained with their initial partner, but 14% of participants separated and repartnered while pursuing fertility treatments. Marital stability significantly predicted the initial status of infertility stress and infertility stress growth levels. Specifically, patients who repartnered had higher infertility stress levels at all time points compared with those who remained in the same relationship, regardless of the partner they were with at assessment. Furthermore, results showed an increasing stress trajectory over time for those who repartnered, compared with those who remained in a stable relationship. Men and women in fertility treatment who form a second union have higher initial levels of stress in their original relationship and higher changes in stress levels over the course of treatments. These findings suggest that high infertility-related stress levels before entering fertility treatment can negatively affect the stability of marital relationships and lead to repartnering. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  3. Stability of class II subdivision malocclusion treatment with 3 and 4 premolar extractions.

    Science.gov (United States)

    Janson, Guilherme; Araki, Janine; Estelita, Sérgio; Camardella, Leonardo T

    2014-12-30

    The purpose of this study was to compare the occlusal stability of class II subdivision malocclusion treatment with 3 and 4 first premolar extractions. A sample of 156 dental casts from 52 patients with class II subdivision malocclusion was divided into two groups according to the extraction protocol. Group 1 comprised 24 patients treated with 3 premolar extractions and group 2 included 28 patients treated with 4 premolar extractions. Peer assessment rating (PAR) indexes were measured on the dental casts obtained before (T1) and after treatment (T2) and at a mean of 6.9 years after the end of treatment (T3). The groups were matching regarding sex distribution, pretreatment, posttreatment and long-term posttreatment ages, and treatment and long-term posttreatment times. They were also comparable concerning the initial malocclusion severity and the occlusal results at the end of treatment. Stability evaluation was calculated by subtracting the posttreatment from the long-term posttreatment index values (T3 - T2). T tests were used to compare the amount and percentage of long-term posttreatment changes. There were no intergroup differences regarding the amount and percentage of long-term posttreatment changes. Treatment of class II subdivision malocclusion with 3 and 4 premolar extractions have a similar long-term posttreatment occlusal stability.

  4. Occlusal stability of adult Class II Division 1 treatment with the Herbst appliance.

    Science.gov (United States)

    Bock, Niko Christian; von Bremen, Julia; Ruf, Sabine

    2010-08-01

    During recent years, some articles have been published on Herbst appliance treatment in adult patients, an approach that has been shown to be most effective in Class II treatment in both early and late adulthood. However, no results on stability have yet been published. Our objective was to analyze the short-term occlusal stability of Herbst therapy in adults with Class II Division 1 malocclusions. The subjects comprised 26 adults with Class II Division 1 malocclusions exhibiting a Class II molar relationship > or =0.5 cusp bilaterally or > or =1.0 cusp unilaterally and an overjet of > or =4.0 mm. The average treatment time was 8.8 months (Herbst phase) plus 14.7 months (subsequent multi-bracket phase). Study casts from before and after treatment and after an average retention period of 32 months were analyzed. After retention, molar relationships were stable in 77.6% and canine relationships in 71.2% of the teeth. True relapses were found in 8.2% (molar relationships) and 1.9% (canine relationships) of the teeth. Overjet was stable in 92.3% and overbite in 96.0% of the patients; true relapse did not occur. Herbst treatment showed good occlusal stability 2.5 years after treatment in adults with Class II Division 1 malocclusions. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  5. Critical study of current situation of Vrănicioara tailing pond on Cavnicului Valley, risks and consequences

    Science.gov (United States)

    Bud, I.; Duma, S.; Gusat, D.; Pasca, I.; Bud, A.

    2017-05-01

    In northern Romania, there are numerous tailing ponds, resulting from mining activities that present significant environmental risks. Some of them, including Vrănicioara tailing pond, were the subject of technical projects for ecological rehabilitation. Vrănicioara pond is located on the right side of Cavnic Valley, downstream Cavnic town, about 4 kilometers far. It has about 500 m length and is located parallel to the road linking Baia Sprie and Cavnic localities. Chemical and physical stability of the tailing pond before rehabilitation interest the research, analysis and conclusions were published in several scientific meetings. In addition, close to the pond at less than 100 m, an open pit has developed, exploiting andesite by mining blast, increasing the risk of physical stability by continuous exposure to vibration. This activity currently continues, advancing towards the tailing pond body. The critical study addresses the current state of Vrănicioara Tailing Pond, analysis of some rehabilitation works done incorrectly, analysis of chemical stability that was not a priority during rehabilitation. Research intention is heading to water analysis confirming the existence of acid drainage that was not stopped or at least reduced. The scientific approach is based on the Technical Standards for Waste Deposits, in force in Romania, providing the rules to ensure physical and chemical stability.

  6. Impact of aerobic stabilization on the characteristics of treatment sludge in the leather tanning industry.

    Science.gov (United States)

    Cokgor, Emine Ubay; Aydinli, Ebru; Tas, Didem Okutman; Zengin, Gulsum Emel; Orhon, Derin

    2014-01-01

    The efficiency of aerobic stabilization on the treatment sludge generated from the leather industry was investigated to meet the expected characteristics and conditions of sludge prior to landfill. The sludge types subjected to aerobic stabilization were chemical treatment sludge, biological excess sludge, and the mixture of both chemical and biological sludges. At the end of 23 days of stabilization, suspended solids, volatile suspended solids and total organic carbon removal efficiencies were determined as 17%, 19% and 23% for biological sludge 31%, 35% and 54% for chemical sludge, and 32%, 34% and 63% for the mixture of both chemical and biological sludges, respectively. Model simulations of the respirometric oxygen uptake rate measurements showed that the ratio of active biomass remained the same at the end of the stabilization for all the sludge samples. Although mixing the chemical and biological sludges resulted in a relatively effective organic carbon and solids removal, the level of stabilization achieved remained clearly below the required level of organic carbon content for landfill. These findings indicate the potential risk of setting numerical restrictions without referring to proper scientific support.

  7. Sludge accumulation in shallow maturation ponds treating UASB reactor effluent: results after 11 years of operation.

    Science.gov (United States)

    Possmoser-Nascimento, Thiago Emanuel; Rodrigues, Valéria Antônia Justino; von Sperling, Marcos; Vasel, Jean-Luc

    2014-01-01

    Polishing ponds are natural systems used for the post-treatment of upflow anaerobic sludge blanket (UASB) effluents. They are designed as maturation ponds and their main goal is the removal of pathogens and nitrogen and an additional removal of residual organic matter from the UASB reactor. This study aimed to evaluate organic matter and suspended solids removal as well as sludge accumulation in two shallow polishing ponds in series treating sanitary effluent from a UASB reactor with a population equivalent of 200 inhabitants in Brazil, operating since 2002. For this evaluation, long-term monitoring of biochemical oxygen demand and total suspended solids and bathymetric surveys have been undertaken. The ponds showed an irregular distribution of total solids mass in the sludge layer of the two ponds, with mean accumulation values of 0.020 m(3) person(-1) year(-1) and 0.004 m(3) person(-1) year(-1) in Ponds 1 and 2, leading to around 40% and 8% of the liquid volume occupied by the sediments after 11 years of operation. The first pond showed better efficiency in relation to organic matter removal, although its contribution was limited, due to algal growth. No simple input-output mass balance of solids can be applied to the ponds due to algal growth in the liquid phase and sludge digestion in the sludge.

  8. Dinâmica de nitrogênio em um sistema de lagoas de estabilização na região do Vale do Ribeira (São Paulo - Brasil Nitrogen dynamic in waste stabilization ponds systems in the Ribeira's Valley region (São Paulo - Brasil

    Directory of Open Access Journals (Sweden)

    Adriana Cristina Poli Miwa

    2007-06-01

    Full Text Available Esta pesquisa teve como principal objetivo investigar os pro-cessos envolvidos nas transformações do nitrogênio em um sistema de lagoas de estabilização. Em amostragem nictemeral (24 horas observou-se forte estratificação térmica durante a maior parte do ciclo amostrado a qual condicionou a compartimentalização vertical e a estratificação química nas duas lagoas, possibilitando a análise dos processos de forma segmentada pela ACP (análise de componentes principais, que mostrou-se ferramenta estatística muito útil na caracterização dos processos. A degradação de proteína, com subseqüente geração e acúmulo de nitrogênio amoniacal, foi observada, além da possível excreção de proteína ou aminoácidos por organismos fitoplanctônicos na superfície das lagoas. A provável ocorrência de nitrificação na superfície da lagoa anaeróbia evidenciou a necessidade de otimização de operação do sistema a fim de viabilizar a remoção de nitrogênio através da desnitrificação, processo provavelmente inibido pelas elevadas concentrações de oxigênio dissolvido registradas durante o dia.This research had as main objective to investigate the involved processes in the transformations of nitrogen in a system of waste stabilization ponds. In nictemeral sampling (24 hours strong thermal stratification was observed during most of the showed cycle which conditioned two vertical compartments and the chemical stratification in the two lagoons, making possible the analysis of the processes of segmented form for PCA (Principal Components Analysis that was a very useful statistics tool in the characterization of the processes. The protein degradation was observed with subsequent generation and accumulation of ammoniacal nitrogen, beyond the possible excretion of protein or amino acids for phytoplanktonic organisms in the surface of the ponds. The probable occurrence of nitrification in the surface layer of the anaerobic pond

  9. Oxytetracycline Assay in Pond Sediment

    OpenAIRE

    L. Nepejchalová; Z. Svobodová; J. Kolářová; K. Frgalová; J. Valová; D. Némethová

    2008-01-01

    The fate of drug residues and their metabolites in the environment is relatively rarely investigated in the conditions of the Czech Republic, resulting in limited availability of scientific information. To demonstrate one example, we prepared a model study with medicated feedstuff containing oxytetracycline hydrochloride (OTC HCl), which was used in fish under normal conditions of use. The oxytetracycline (OTC) contents were determined in the sediments of the pond where the fish were treated....

  10. In vitro analysis of the influence of surface treatment of dental implants on primary stability

    Directory of Open Access Journals (Sweden)

    Carla Rodrigues Mazzo

    2012-08-01

    Full Text Available Surface treatment interferes with the primary stability of dental implants because it promotes a chemical and micromorphological change on the surface and thus stimulates osseointegration. This study aimed to evaluate the effects of different surface treatments on primary stability by analyzing insertion torque (IT and pullout force (PF. Eight samples of implants with different surface treatments (TS - external hexagon with acid surface treatment; and MS - external hexagon, machined surface, all 3.75 mm in diameter X 11.5 mm in length, were inserted into segments of artificial bones. The IT of each sample was measured by an electronic torquemeter, and then the pullout test was done with a universal testing machine. The results were subjected to ANOVA (p < 0.05, followed by Tukey's test (p < 0.05. The IT results showed no statistically significant difference, since the sizes of the implants used were very similar, and the bone used was not highly resistant. The PF values (N were, respectively, TS = 403.75 ± 189.80 and MS = 276.38 ± 110.05. The implants were shown to be different in terms of the variables of maximum force (F = 4.401, p = 0.0120, elasticity in maximum flexion (F = 3.672, p = 0.024, and relative stiffness (F = 4.60, p = 0.01. In this study, external hexagonal implants with acid surface treatment showed the highest values of pullout strength and better stability, which provide greater indication for their use.

  11. Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents

    Directory of Open Access Journals (Sweden)

    Henry-Silva Gustavo Gonzaga

    2006-01-01

    Full Text Available The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants. Water samples were collected from the: (i fish pond source water, (ii effluent from fish pond and (iii effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively and total nitrogen removal (46.1% and 43.9%, respectively than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen and the control (50.3% total phosphorus and 22.8% total nitrogen, indicating that the treated effluents may be reused in the aquaculture activity.

  12. Treatment stabilization in children and adolescents with attention-deficit/hyperactivity disorder: data from the Netherlands.

    Science.gov (United States)

    Sasané, Rahul; Hodgkins, Paul; Meijer, Willemijn

    2010-11-01

    To evaluate the number of patients reaching stable treatment with a stimulant (methylphenidate or dexamphetamine) or non-stimulant (atomoxetine) attention-deficit/hyperactivity disorder (ADHD) medication approved for use in the Netherlands, and the time to treatment stabilization among children and adolescents aged 6-17 years. Prescription data from the PHARMO medical record linkage system from 48 geo-demographic areas in the Netherlands (2003-2006) were analyzed from newly treated patients with ADHD aged 6-17 years. Only patients with ≥ 5 dispensings for any ADHD drug during follow-up (at least 12 months) and no missing information on type of drug, strength, and number of pills per day were included. Attainment of a stable dosing regimen was defined as no change in type of drug (including a switch from an immediate release (IR) to a long-acting (LA) formulation), strength, and number of pills per day for five consecutive dispensings. Time to stable dosing regimen was defined as the number of days between the first dispensing for an ADHD drug and the first of five unchanged dispensings. Of 4909 children or adolescents initiating treatment, 3099 met selection criteria. More patients starting therapy with LA methylphenidate (82.4%) achieved treatment stabilization during follow-up than with IR methylphenidate (74.8%; p dose compared to those initiated on IR methylphenidate (25.3%) or atomoxetine (8.1%; p pills per day varied between 1.0 and 1.8 at initial treatment and 1.1 and 1.9 at treatment stabilization. Potential limitations of the study include the use of ADHD-medication dispensing as a proxy for an ADHD diagnosis and the impact of different titration schedules for the various ADHD medications. Overall, 2316 of the 3066 eligible patients (75.5%) achieved treatment stabilization during follow-up. Among children and adolescents with ADHD in the Netherlands, the time to treatment stabilization varied according to choice of initial treatment and was shortest for

  13. Effects of pond draining on biodiversity and water quality of farm ponds.

    Science.gov (United States)

    Usio, Nisikawa; Imada, Miho; Nakagawa, Megumi; Akasaka, Munemitsu; Takamura, Noriko

    2013-12-01

    Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large-scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond-management practices, pond physicochemistry, and surrounding land use. The results of boosted regression-tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo. © 2013 Society for Conservation Biology.

  14. Geomembrane selection criteria for uranium tailings ponds

    International Nuclear Information System (INIS)

    Mitchell, D.H.; Cuello, R.

    1986-09-01

    The selection criteria, particularly those involving chemical compatibility, of geomembranes to be used in ponds at uranium mill operations are discussed. The principal functional criteria which a geomembrane must meet for this application are: (1) a specified service life and (2) low permeability. Chemical compatibility with the waste is essential in meeting these functional criteria. In two different types of aging tests using simulated acidic uranium mill waste, degradation of chemical and physical properties were examined in geomembranes of high-density polyethylene, polyvinyl chloride, and chlorosulfonated polyethylene. Compatibility tests according to the National Sanitation Foundation procedures are recommended to ascertain the stability of certain physical properties of the proposed geomembrane. Actual experience with a specific geomembrane in an identical application is probably the best method to assure compatibility; however, this experience is frequently not available. Experience with a geomembrane in similar applications is valuable in the selection process, however, small differences in either the geomembrane formulation or the waste composition may result in large differences in performance of the geomembrane. It is likely that many geomembranes have acceptable chemical stability for typical uranium mill applications, therefore, additional factors in the selection processes will include seaming characteristics, mechanical properties, site characteristics, and costs

  15. Thermal Treatment of Iron Oxide Stabilized APC Residues from Waste Incineration and the Effect on Heavy Metal Binding

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Stackpoole, M.; Bender-Koch, C.

    2000-01-01

    Iron oxide stabilized APC residues from MSWI were heat treated at 600°C and 900°C. The thermal treatments resulted in a change in product stability by forcing a transformation in the mineralogical structures of the products. The treatments, moreover, simulated somewhat the natural aging processes...... that would take place in a stabilized residue. Consequent changes in crystalline structure and heavy metal binding were examined....

  16. Response to "Treatment compliance and effectiveness in complex PTSD patients with co-morbid personality disorder undergoing stabilizing cognitive behavioral group treatment: a preliminary study"

    NARCIS (Netherlands)

    de Jongh, A.; ten Broeke, E.

    2014-01-01

    Last November, the European Journal of Psychotraumatology published an interesting paper entitled "Treatment compliance and effectiveness in complex PTSD patients with co-morbid personality disorder undergoing stabilizing cognitive behavioral group treatment: a preliminary study". This article

  17. Nitrification and denitrification in pond

    Directory of Open Access Journals (Sweden)

    Yuni Puji Pujihastuti

    2011-01-01

    Full Text Available More of waste than pond aquacultutre system produced, will increase sedimentation in the bottom.  Ammonium and nitrite compounds are other forms of inorganic nitrogen in the pond. Nitrogen anorganic consist of ammonia, ammonium, nitrit, nitrat and nitrogen. Degradation of process metabolic biota culture waste can biologically be nitrat compound one of the forms that are not toxic in the nitrification process.  Five process of nitrogen biogeochemical cycle in the container cultivation is the amonification, nitrification, nitrogen assimilation, denitrification and nitrogen fixation. Nitrogen is the one of the compound in the overlay/ top stratification sediment.  Improvement of speed degradation will be success if the pond bottom on aerobic condition. Survival rate of tiger shrimp in the laboratory scale can be increase by administration of nitrification and denitrification bacteria should not just in the water kolom of pond engineering but also at the bottom pond layer at the preparation step.  Depht of the sediment 15 cm in day zero, intensive pond have been produced of nitrit and ammonium with the producing bacteria.  Application of nitrification and denitrification bacteria in the sediment and water coloum can be performed as the measurenment and evaluation nitrit, nitrat and ammonium abudance. Key words:  ponds, nitrogen inorganic, nitrification, denitrification   ABSTRAK Semakin banyak limbah kegiatan yang dihasilkan dalam sistem budidaya tambak, akan meningkatkan sedimentasi dalam dasar tambak.  Senyawa amonium dan nitrit merupakan bentuk lain dari nitrogen anorganik dalam tambak. Nitrogen anorganik terdiri terdiri dari amonia (NH3-, amonium (NH4+, nitrit (NO2-, dan nitrogen (N2. Secara biologis, proses perombakan sisa metabolisme biota budidaya dapat menjadi nitrat (NO3, suatu bentuk yang tidak berbahaya dalam proses nitrifikasi.  Lima proses siklus biogeokimia nitrogen yang terjadi di wadah budidaya adalah amonifikasi

  18. Solar pond conception - experimental and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, Huseyin [Zonguldak Karaelmas Univ., Technical Education Faculty, Karabuk (Turkey); Halici, Fethi [Sakarya Univ., Mechanical Engineering Dept., Adapazari (Turkey); Binark, A. Korhan [Marmara Univ., Technical Education Faculty, Istanbul (Turkey)

    2000-07-01

    A one dimensional transient mathematical model for predicting the thermal performance of the salt gradient solar pond is developed and presented. In this paper, the natural solar ponds and different artificial solar pond systems found in the literature are introduced. Necessary modifications are made on the experimental stand located in Istanbul Technical University, the experimental stand is introduced and natural phenomena produced in the pond by the different solar pond variations under natural conditions are observed. In the theoretical work based on a one dimensional unsteady state heat conduction model with internal heat generation, the energy and mass balance equations for the upper convective zone, the non-convective zone and the lower convective zone, all of which form the solar pond, are written in terms of differential equations. These equations are solved analytically and numerically. The results obtained from the analysis are compared with the experimental results. The temperature and the concentration profiles are separately presented in the figures. (Author)

  19. [Stabilization Treatment of Pb and Zn in Contaminated Soils and Mechanism Studies].

    Science.gov (United States)

    Xie, Wei-qiang; Li, Xiao-mingi; Chen, Can; Chen, Xun-feng; Zhong, Yu; Zhong, Zhen-yu; Wan, Yong; Wang, Yan

    2015-12-01

    In the present work, the combined application of potassium dihydrogen phosphate, quick lime and potassium chloride was used to immobilize the Pb and Zn in contaminated soils. The efficiency of the process was evaluated through leaching tests and Tessier sequential extraction procedure. The mechanism of stabilization was analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) to reveal the mechanism of stabilization. The results showed that the stabilizing efficiency of Pb contaminated soils was above 80% and the leaching concentrations of Pb, Zn were far below the threshold when the ratio of exogenous P and soil (mol · mol⁻¹) was 2:1-4: 1, the dosing ratio of CaO was 0.1%-0.5% ( mass fraction) and the dosage of potassium chloride was 0.02-0. 04 mol. Meanwhile, Pb and Zn in soil were transformed from the exchangeable fraction into residual fraction, which implied that the migration of Pb, Zn in soil could be confined by the stabilization treatment. XRD and SEM analysis revealed that Ca-P-Pb precipitation, lead orthophosphate [PbHP0₄, Pb₃ (PO₄)₂], pyromorphite (Pb-PO₄-Cl/OH) and mixed heavy metal deposits (Fe-PO₄- Ca-Pb-Zn-OH) could be formed after solidification/stabilization in which Pb and Zn could be wrapped up to form a solidified composition and to prevent leaching.

  20. uG-LilyPond - Floating Plant Pond for Microgravity, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed μG-LilyPond is an autonomous environmentally controlled floating plant cultivation system for use in microgravity. The μG-LilyPond concept expands the...

  1. Stability analysis of an HIV/AIDS epidemic model with treatment

    Science.gov (United States)

    Cai, Liming; Li, Xuezhi; Ghosh, Mini; Guo, Baozhu

    2009-07-01

    An HIV/AIDS epidemic model with treatment is investigated. The model allows for some infected individuals to move from the symptomatic phase to the asymptomatic phase by all sorts of treatment methods. We first establish the ODE treatment model with two infective stages. Mathematical analyses establish that the global dynamics of the spread of the HIV infectious disease are completely determined by the basic reproduction number [real]0. If [real]01. Then, we introduce a discrete time delay to the model to describe the time from the start of treatment in the symptomatic stage until treatment effects become visible. The effect of the time delay on the stability of the endemically infected equilibrium is investigated. Moreover, the delay model exhibits Hopf bifurcations by using the delay as a bifurcation parameter. Finally, numerical simulations are presented to illustrate the results.

  2. Capacidade da lagoa de estabilização, integrante de um sistema piloto, na remoção da carga orgânica da água residuária do processamento do café por via úmida Capability of a stabilization pond, part of a pilot system, of removing the organic load of wet coffee processing wastewater

    Directory of Open Access Journals (Sweden)

    Júlia Ferreira da Silva

    2010-12-01

    Full Text Available O processamento do café por via úmida, além de aumentar a eficiência para se obter cafés de melhor qualidade, diminui consideravelmente os custos de secagem e ainda, reduz o espaço ocupado no terreiro. Porém, esse tipo de processamento gera grandes quantidades de águas residuárias, que devem sofrer algum tipo de tratamento antes de serem lançadas em corpos hídricos. Nesta pesquisa, objetivou-se monitorar a Lagoa de Estabilização integrante desse sistema, avaliar a sua eficiência na remoção da carga orgânica afluente e desenvolver um modelo de ajuste para descrever a autodepuração ocorrida. Para esta pesquisa, foram considerados 300,200 litros de frutos do cafeeiro, da espécie Coffea arabica L., processados, por via úmida. A carga média diária foi de 136 kgDQO d-1, encaminhada para um sistema piloto de tratamento de água residuária do processamento do café. O monitoramento foi realizado por meio de análises químicas e físico-químicas e o modelo de ajuste foi desenvolvido a partir do cálculo do balanço hídrico, das equações de estimativa teórica de remoção de DQO e das análises de DQO realizadas. O efluente da lagoa de estabilização apresentou concentração inicial de DQO de 7,100 mg L-1 e final de 100 mg L-1. Ficou constatado que a lagoa foi a unidade de tratamento que reduziu em cerca de 80% a concentração de matéria orgânica afluente. O modelo de ajuste desenvolvido apresentou coeficiente de ajuste satisfatório (r² = 0,8015.Wet coffee processing, besides its efficiency in getting better coffee quality, also minimizes considerably drying costs, and moreover reduces the space due to the ground-flour spreading seeds. However, this type of processing produces large quantities of wastewater, which must be treated before being discharged into the sewage system. The main objective of this research was to monitor the stabilization pond, as part of a pilot system, and therefore, to evaluate its efficiency

  3. THE ASSESMENT OF THE EFFICENCY AND STABILITY OF WORK SEWAGE TREATMENT PLANT IN ZABAJKA

    Directory of Open Access Journals (Sweden)

    Dariusz Młyński

    2016-05-01

    Full Text Available In the article the assessment of the efficiency and stability of work sewage treatment plant in Zabajka was performed based on the results of the physico-chemical measurements raw sewage and treated sewage noted in the period between 2010 and 2014. The analysis was performed for the following pollutants indicators: BOD5, CODCr and total suspended solids. For each of them descriptive statistics, percentage reduction the pollutants indicators and treatment plant reliability factors (WN were calculated. The assessment of the stability of work of sewage treatment plant was performed by using control cards X for the simple test. Based on the obtained results, it was concluded that sewage treatment plant in Zabajka works properly, what is confirmed by high values of the pollutants indicators reduction and the values of WN, which are less than 1.00. The analysis of the control cards indicates instability of the treatment process only for CODCr, but it does not impact on treatment efficiency in relation to this indicator.

  4. Role of water balance in the long-term stability of hazardous waste site cover treatments

    International Nuclear Information System (INIS)

    Barnes, F.J.; Rodgers, J.C.; Trujillo, G.

    1986-01-01

    After the 30-year post-closure maintenance period at hazardous waste landfills, long-term stability must be assured without continued intervention. Understanding water balance in the established vegetative cover system is central to predicting such stability. A Los Alamos National Laboratory research project has established a series of experimental cover treatment plots on a closed waste disposal site which will permit the determination of the effects of such critical parameters as soil cover design, leaf area index, and rooting characteristics on water balance under varied conditions. Data from these experiments are being analyzed by water balance modeling and other means. The results show consistent differences in soil moisture storage between soil profiles and between vegetation cover treatments

  5. Stability of class II subdivision malocclusion treatment with 3 and 4 premolar extractions

    OpenAIRE

    Janson, Guilherme; Araki, Janine; Estelita, S?rgio; Camardella, Leonardo T

    2014-01-01

    Background The purpose of this study was to compare the occlusal stability of class II subdivision malocclusion treatment with 3 and 4 first premolar extractions. A sample of 156 dental casts from 52 patients with class II subdivision malocclusion was divided into two groups according to the extraction protocol. Group 1 comprised 24 patients treated with 3 premolar extractions and group 2 included 28 patients treated with 4 premolar extractions. Methods Peer assessment rating (PAR) indexes we...

  6. Road Salts as Environmental Constraints in Urban Pond Food Webs

    Science.gov (United States)

    Van Meter, Robin J.; Swan, Christopher M.

    2014-01-01

    Freshwater salinization is an emerging environmental filter in urban aquatic ecosystems that receive chloride road salt runoff from vast expanses of impervious surface cover. Our study was designed to evaluate the effects of chloride contamination on urban stormwater pond food webs through changes in zooplankton community composition as well as density and biomass of primary producers and consumers. From May – July 2009, we employed a 2×2×2 full-factorial design to manipulate chloride concentration (low = 177 mg L−1 Cl−/high = 1067 mg L−1 Cl−), gray treefrog (Hyla versicolor) tadpoles (presence/absence) and source of stormwater pond algae and zooplankton inoculum (low conductance/high conductance urban ponds) in 40, 600-L mesocosms. Road salt did serve as a constraint on zooplankton community structure, driving community divergence between the low and high chloride treatments. Phytoplankton biomass (chlorophyll [a] µg L−1) in the mesocosms was significantly greater for the high conductance inoculum (Psalts among algal resources and zooplankton taxa, and further suggest that road salts can act as a significant environmental constraint on urban stormwater pond communities. PMID:24587259

  7. Application of landfill treatment approaches for stabilization of municipal solid waste.

    Science.gov (United States)

    Bolyard, Stephanie C; Reinhart, Debra R

    2016-09-01

    This research sought to compare the effectiveness of three landfill enhanced treatment approaches aimed at removing releasable carbon and nitrogen after anaerobic landfilling including flushing with clean water (FB 1), leachate recirculation with ex-situ treatment (FB 2), and leachate recirculation with ex-situ treatment and in-situ aeration (FB 3). After extensive treatment of the waste in the FB scenarios, the overall solids and biodegradable fraction were reduced relative to the mature anaerobically treated waste. In terms of the overall degradation, aeration did not provide any advantage over flushing and anaerobic treatment. Flushing was the most effective approach at removing biodegradable components (i.e. cellulose and hemicellulose). Leachate quality improved for all FBs but through different mechanisms. A significant reduction in ammonia-nitrogen occurred in FB 1 and 3 due to flushing and aeration, respectively. The reduction of chemical oxygen demand (COD) in FB 1 was primarily due to flushing. Conversely, the reduction in COD in FBs 2 and 3 was due to oxidation and precipitation during Fenton's Reagent treatment. A mass balance on carbon and nitrogen revealed that a significant fraction still remained in the waste despite the additional treatment provided. Carbon was primarily converted biologically to CH4 and CO2 in the FBs or removed during treatment using Fenton's Reagent. The nitrogen removal occurred through leaching or biological conversion. These results show that under extensive treatment the waste and leachate characteristics did meet published stability values. The minimum stability values achieved were through flushing although FB 2 and 3 were able to improve leachate quality and solid waste characteristics but not to the same extent as FB 1. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Efficiency, effectiveness and treatment stability of clear aligners: A systematic review and meta-analysis.

    Science.gov (United States)

    Zheng, M; Liu, R; Ni, Z; Yu, Z

    2017-08-01

    The objective of this study was to perform a systematic review of the orthodontic literature with regard to efficiency, effectiveness and stability of treatment outcome with clear aligners compared with treatment with conventional brackets. An electronic search without time or language restrictions was undertaken in October 2014 in the following electronic databases: Google Scholar, the Cochrane Oral Health Group's Trials Register, Scopus, CENTRAL, MEDLINE via OVID, EMBASE via OVID and Web of Science. We also searched the reference lists of relevant articles. Quality assessment of the included articles was performed. Two authors were responsible for study selection, validity assessment and data extraction. Four controlled clinical trials including a total of 252 participants satisfied the inclusion criteria. We grouped the trials into four main comparisons. One randomized controlled trial was classified as level 1B evidence, and three cohort studies were classified as level 2B evidence. Clear aligners appear to have a significant advantage with regard to chair time and treatment duration in mild-to-moderate cases based on several cross-sectional studies. No other differences in stability and occlusal characteristics after treatment were found between the two systems. Despite claims about the effectiveness of clear aligners, evidence is generally lacking. Shortened treatment duration and chair time in mild-to-moderate cases appear to be the only significant effectiveness of clear aligners over conventional systems that are supported by the current evidence. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. A mini review: proteoglycan aggregate profiles in the Pond-Nuki dog model of osteoarthritis and in canine disuse atrophy.

    Science.gov (United States)

    Howell, D S; Muller, F; Manicourt, D H

    1992-01-01

    The Pond-Nuki dog model of osteoarthritis has characteristics which seem to mimic the human disease in early stages, particularly with respect to progressive changes in the cartilage matrix. Aggregating proteoglycans were studied using novel extraction and ultracentrifugation methods designed to separate very large macromolecules. With these methods two large peaks of proteoglycan (PG) aggregates (PGA-1 and PGA-2) were separated in preparative amounts and were shown to have unequivocal differences in composition in many respects. The profiles of these peaks have been studied as a function of joint location, topographic site, cartilage layer, presence of cartilage atrophy versus osteoarthritis, as well as treatment of the animals with various agents. Both link protein (essential for forming link-protein stabilized aggregates) and hyaluronate are required to regenerate normal aggregate profiles from the deficient aggregate fractions obtained from osteoarthritic cartilage. Canine proteoglycan link-stabilized aggregates (PGA-2) are confined to the middle and deep zone of cartilage. We believe that their reduction or elimination in the Pond-Nuki model results from a disturbance or loss of functional link protein (and hyaluronate), thereby weakening the middle and deep cartilage layers.

  10. Leachate characterization and performance evaluation of leachate treatment plant in Cipayung landfill, Indonesia

    Science.gov (United States)

    Noerfitriyani, E.; Hartono, D. M.; Moersidik, S. S.; Gusniani, I.

    2018-01-01

    The operation of landfill can cause environmental problems due to waste decomposition in the form of leachate production. Cipayung Landfill has a leachate treatment plant using stabilization ponds. The objective of this research is to evaluate the performance of stabilization ponds at Cipayung Landfill. The data were analyzed based on leachate samples from treatment unit’s influent and effluent under rainy season condition from April to May 2017. The results show the average leachate quality based on parameters of temperature by 34.81°C, Total Suspended Solid (TSS) of 72.33 mg/L, pH of 7.83, Biochemical Oxygen Demand (BOD) of 3,959.63 mg/L, Chemical Oxygen Demand (COD) of 6,860 mg/L, Total Nitrogen of 373.33 mg/L, and heavy metal Mercury of 0.0016 mg/L. The treatment plant’s effluent quality exceeds the leachate standard limit based on Indonesia’s Ministry of Environment and Forestry Law No. 59 of 2016. The results of design evaluation show that the anaerobic pond, facultative pond, and maturation pond system do not meet the design criteria. Therefore, a design improvement is needed to increase the performance of the leachate treatment plant and to ensure that the leachate discharged to water bodies does not exceed the standard limit to prevent contamination of the environment.

  11. A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, Cicero W.B. [Institute for Fuel Cell Innovation, National Research Council of Canada, Vancouver, BC V6T 1W5 (Canada); Department of Chemistry, Universidade Federal do Maranhao, Av. dos Portugueses, S/N 65.080-040 Sao Luis, MA (Brazil); Zhang, Lei; Liu, Hansan; Lee, Kunchan; Wang, Haijiang; Zhang, Jiujun [Institute for Fuel Cell Innovation, National Research Council of Canada, Vancouver, BC V6T 1W5 (Canada); Marques, Aldalea L.B. [Department of Technology Chemistry, Universidade Federal do Maranhao, Sao Luis, MA (Brazil); Marques, Edmar P. [Department of Chemistry, Universidade Federal do Maranhao, Av. dos Portugueses, S/N 65.080-040 Sao Luis, MA (Brazil)

    2007-11-15

    This paper reviews over 120 papers regarding the effect of heat treatment on the catalytic activity and stability of proton exchange membrane (PEM) fuel cell catalysts. These catalysts include primarily unsupported and carbon-supported platinum (Pt), Pt alloys, non-Pt alloys, and transition metal macrocycles. The heat treatment can induce changes in catalyst properties such as particle size, morphology, dispersion of the metal on the support, alloying degree, active site formation, catalytic activity, and catalytic stability. The optimum heat-treatment temperature and time period are strongly dependent on the individual catalyst. With respect to Pt-based catalysts, heat treatment can induce particle-size growth, better alloying degree, and changes in the catalyst surface morphology from amorphous to more ordered states, all of which have a remarkable effect on oxygen reduction reaction (ORR) activity and stability. However, heat treatment of the catalyst carbon supports can also significantly affect the ORR catalytic activity of the supported catalyst. Regarding non-noble catalysts, in particular transition metal macrocycles, heat treatment is also important in ORR activity and stability improvement. In fact, heat treatment is a necessary step for introducing more active catalytic sites. For metal chalcogenide catalysts, it seems that heat treatment may not be necessary for catalytic activity and stability improvement. More research is necessary to improve our fundamental understanding and to develop a new strategy that includes innovative heat-treatment processes for enhancing fuel cell catalyst activity and stability. (author)

  12. A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction

    Science.gov (United States)

    Bezerra, Cicero W. B.; Zhang, Lei; Liu, Hansan; Lee, Kunchan; Marques, Aldaléa L. B.; Marques, Edmar P.; Wang, Haijiang; Zhang, Jiujun

    This paper reviews over 120 papers regarding the effect of heat treatment on the catalytic activity and stability of proton exchange membrane (PEM) fuel cell catalysts. These catalysts include primarily unsupported and carbon-supported platinum (Pt), Pt alloys, non-Pt alloys, and transition metal macrocycles. The heat treatment can induce changes in catalyst properties such as particle size, morphology, dispersion of the metal on the support, alloying degree, active site formation, catalytic activity, and catalytic stability. The optimum heat-treatment temperature and time period are strongly dependent on the individual catalyst. With respect to Pt-based catalysts, heat treatment can induce particle-size growth, better alloying degree, and changes in the catalyst surface morphology from amorphous to more ordered states, all of which have a remarkable effect on oxygen reduction reaction (ORR) activity and stability. However, heat treatment of the catalyst carbon supports can also significantly affect the ORR catalytic activity of the supported catalyst. Regarding non-noble catalysts, in particular transition metal macrocycles, heat treatment is also important in ORR activity and stability improvement. In fact, heat treatment is a necessary step for introducing more active catalytic sites. For metal chalcogenide catalysts, it seems that heat treatment may not be necessary for catalytic activity and stability improvement. More research is necessary to improve our fundamental understanding and to develop a new strategy that includes innovative heat-treatment processes for enhancing fuel cell catalyst activity and stability.

  13. Divergent hydrological responses to 20th century climate change in shallow tundra ponds, western Hudson Bay Lowlands

    Science.gov (United States)

    Wolfe, Brent B.; Light, Erin M.; Macrae, Merrin L.; Hall, Roland I.; Eichel, Kaleigh; Jasechko, Scott; White, Jerry; Fishback, LeeAnn; Edwards, Thomas W. D.

    2011-12-01

    The hydrological fate of shallow tundra lakes and ponds under conditions of continued warming remains uncertain, but has important implications for wildlife habitat and biogeochemical cycling. Observations of unprecedented pond desiccation, in particular, signify catastrophic loss of aquatic habitat in some Arctic locations. Shallow tundra ponds are a ubiquitous feature in the western Hudson Bay Lowlands (HBL), a region that has undergone intense warming over the past ˜50 years. But it remains unknown how hydrological processes in these ponds have responded. Here, we use cellulose-inferred pond water oxygen isotope records from sediment cores, informed by monitoring of modern pond water isotope compositions during the 2009 and 2010 ice-free seasons, to reconstruct hydrological conditions of four shallow tundra ponds in the western HBL over the past three centuries. Following an interval of relative hydrological stability during the early part of the records, results reveal widely differing hydrological responses to 20th century climate change among the study sites, which is largely dependent on hydrological connectivity of the basins within their respective surrounding peatlands. These findings suggest the 20th century has been characterized by an increasingly dynamic landscape that has variably influenced surface water balance - a factor that is likely to play a key role in determining the future water balance of ponds in this region.

  14. Balancing the Ecological Function of Residential Stormwater Ponds with Homeowner Landscaping Practices.

    Science.gov (United States)

    Monaghan, Paul; Hu, Shangchun; Hansen, Gail; Ott, Emily; Nealis, Charles; Morera, Maria

    2016-11-01

    Stormwater ponds are installed in urban developments to provide the ecosystem services of flood control and water treatment. In coastal areas, these ponds are connected to watersheds that can drain directly into protected estuaries, making their design, function, and maintenance critical to environmental protection. However, stormwater ponds in residential areas are increasingly managed as aesthetic amenities that add value to real estate rather than as engineered devices with special maintenance requirements. To help extend the life of neighborhood stormwater systems and improve ecosystem services, homeowners should follow best management practices for nutrient management and add shoreline plantings and non-invasive, beneficial aquatic plants to their ponds. This study used focus group and survey research to document the knowledge, behaviors, and attitudes of homeowners living near stormwater ponds in a master-planned community in Florida. The study was designed to use a social marketing research approach to promote Extension best practices. Findings indicate that many residents were aware of the functional components of stormwater systems and respondents' receptivity to best management practices was mediated by age, their attitudes about water quality and whether their home was adjacent to a pond. These findings can be used to target Extension audiences and improve adoption of stormwater pond best management practices for increased protection of water quality.

  15. Balancing the Ecological Function of Residential Stormwater Ponds with Homeowner Landscaping Practices

    Science.gov (United States)

    Monaghan, Paul; Hu, Shangchun; Hansen, Gail; Ott, Emily; Nealis, Charles; Morera, Maria

    2016-11-01

    Stormwater ponds are installed in urban developments to provide the ecosystem services of flood control and water treatment. In coastal areas, these ponds are connected to watersheds that can drain directly into protected estuaries, making their design, function, and maintenance critical to environmental protection. However, stormwater ponds in residential areas are increasingly managed as aesthetic amenities that add value to real estate rather than as engineered devices with special maintenance requirements. To help extend the life of neighborhood stormwater systems and improve ecosystem services, homeowners should follow best management practices for nutrient management and add shoreline plantings and non-invasive, beneficial aquatic plants to their ponds. This study used focus group and survey research to document the knowledge, behaviors, and attitudes of homeowners living near stormwater ponds in a master-planned community in Florida. The study was designed to use a social marketing research approach to promote Extension best practices. Findings indicate that many residents were aware of the functional components of stormwater systems and respondents' receptivity to best management practices was mediated by age, their attitudes about water quality and whether their home was adjacent to a pond. These findings can be used to target Extension audiences and improve adoption of stormwater pond best management practices for increased protection of water quality.

  16. Determination of the algal growth-limiting nutrients in strip mine ponds

    International Nuclear Information System (INIS)

    Bucknavage, M.J.; Aharrah, E.C.

    1984-01-01

    Using both a test organism, Ankistrodesmus falcatus, and natural phytoplankton, the Printz Algal Assay Bottle Test was used to determine the algal growth limiting nutrients in two strip mine ponds. Nitrogen, phosphorus, and iron were investigated, singly and in combination, as possible limiting nutrients. A synthetic chelator, Na 2 EDTA, was also used in the assay to test for the presence of metal toxicants and/or trace metal limitation. Because bacteria have a major influence on water chemistry, a separate assay incorporating the natural bacteria population was performed. In both ponds, assay results using test alga indicate phosphorus to be the primary limiting nutrient and nitrogen as a secondary factor. The presence of EDTA in combination with phosphate containing treatment promoted a higher algal concentration in both ponds. Iron was determined to be a secondary limiting nutrient in only one of the ponds. Natural phytoplankton of the two ponds responded in a similar manner to nutrient increases. Only one pond had the same results produced by both assays. Nutrient availability was influenced by the presence of bacteria in one pond but not in the other

  17. Organic matter decomposition in simulated aquaculture ponds

    NARCIS (Netherlands)

    Torres Beristain, B.

    2005-01-01

    Different kinds of organic and inorganic compounds (e.g. formulated food, manures, fertilizers) are added to aquaculture ponds to increase fish production. However, a large part of these inputs are not utilized by the fish and are decomposed inside the pond. The microbiological decomposition of the

  18. Par Pond vegetation status Summer 1995 -- Summary

    International Nuclear Information System (INIS)

    Mackey, H.E. Jr.; Riley, R.S.

    1996-01-01

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995. Communities similar to the pre-drawdown, Par Pond aquatic plant communities are becoming re-established. Emergent beds of maidencane, lotus, waterlily, and watershield are extensive and well developed. Cattail occurrence continued to increase during the summer, but large beds common to Par Pond prior to the drawdown have not formed. Estimates from SPOT HRV, remote sensing satellite data indicated that as much as 120 hectares of emergent wetlands vegetation may have been present along the Par Pond shoreline by early October, 1995. To track the continued development of macrophytes in Par Pond, future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  19. Sydney Tar Ponds Remediation: Experience to China

    Science.gov (United States)

    Liu, Fan; Bryson, Ken A.

    2009-01-01

    The infamous "Sydney Tar Ponds" are well known as one of the largest toxic waste sites of Canada, due to almost 100 years of steelmaking in Sydney, a once beautiful and peaceful city located on the east side of Cape Breton Island, Nova Scotia. This article begins with a contextual overview of the Tar Ponds issue including a brief…

  20. Manual therapy and segmental stabilization in the treatment of cervical radiculopathy

    Directory of Open Access Journals (Sweden)

    Rafael Souza Aquaroli

    Full Text Available Abstract Introduction: Cervical radiculopathy (CR is one of the diseases that most affect the cervical spine, causing radicular symptoms in the ipsilateral limb. Conservative treatment aim recover of both mechanical and physiological functions through neural mobilization techniques, along with the activation of the deep neck flexors with cervical segmental stabilization, combining techniques of joint mobilization and manipulation, which seeks mobility improvement of crucial areas of the cervical spine. The objective of this study was to evaluate a multimodal treatment to enhance the outcomes of conservative care in patients diagnosed with CR. Methods: The sample consisted of 11 patients with CR, between 21 and 59 years old, 3 female and 8 male. It was recorded the Visual Analogue Scale (VAS for pain, the Functional Development of the Neck Pain and Disability Scale (NPDS and the goniometry during shoulder abduction. The intervention plan was composed by neural mobilization, intermittent cervical traction, pompages, stretching, myofascial inhibition techniques, manipulative techniques and cervical segmental stabilization exercises. After 12 weeks of treatment, subjects underwent a new evaluation process. Results: Before the treatment, subjects reported an average pain of 7 (± 1.48 in VAS, whose dropped to average 1.18 (± 1.99 (p < 0.01. Functional disability evaluated in NPDS was 36 (± 10.95 before treatment decreasing to 11.45 (± 9.8 (p < 0.01 after the treatment. Range of motion of the ipsilateral upper limb was restores by increasing from 9.2° (± 8.2 to 137° (± 24.4 (p < 0.01. Conclusion: The proposed treatment approach was effective, significantly improving the results of analgesia and functional disability a series of cases of patients diagnosed with cervical radiculopathy. {#}

  1. Stability of additive treatment effects in multiple treatment comparison meta-analysis: a simulation study

    Directory of Open Access Journals (Sweden)

    Mills E

    2012-04-01

    Full Text Available Kristian Thorlund1, Edward Mills1,21Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, 2Faculty of Health Sciences, University of Ottawa, Ottawa, ON, CanadaBackground: Many medical interventions are administered in the form of treatment combinations involving two or more individual drugs (eg, drug A + drug B. When the individual drugs and drug combinations have been compared in a number of randomized clinical trials, it is possible to quantify the comparative effectiveness of all drugs simultaneously in a multiple treatment comparison (MTC meta-analysis. However, current MTC models ignore the dependence between drug combinations (eg, A + B and the individual drugs that are part of the combination. In particular, current models ignore the possibility that drug effects may be additive, ie, the property that the effect of A and B combined is equal to the sum of the individual effects of A and B. Current MTC models may thus be suboptimal for analyzing data including drug combinations when their effects are additive or approximately additive. However, the extent to which the additivity assumption can be violated before the conventional model becomes the more optimal approach is unknown. The objective of this study was to evaluate the comparative statistical performance of the conventional MTC model and the additive effects MTC model in MTC scenarios where additivity holds true, is mildly violated, or is strongly violated.Methods: We simulated MTC scenarios in which additivity held true, was mildly violated, or was strongly violated. For each scenario we simulated 500 MTC data sets and applied the conventional and additive effects MTC models in a Bayesian framework. Under each scenario we estimated the proportion of treatment effect estimates that were 20% larger than ‘the truth' (ie, % overestimates, the proportion that were 20% smaller than ‘the truth' (ie, % underestimates,The coverage of the 95% credible

  2. Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.; Silvers, Kurt L.; Baker, Aaron B.; Gano, Susan R.; Thornton, Brenda M.

    2000-09-28

    This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantify the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.

  3. Chromate abatement in the Y-12 Plant's New Hope Pond

    International Nuclear Information System (INIS)

    DeMonbrum, J.R.; Muenzer, W.A.

    1975-01-01

    Results are reported from a 15-months field study that utilized four nonchromate-based water-treatment programs in 16 low-temperature (less than 100 0 F) cooling towers using corrosion and deposition studies, microbiological control, and plant effluent creek analyses as evaluation parameters. The study succeeded in bringing the chromate content of effluent of the New Hope Pond at the Oak Ridge Y-12 Plant to the limits established by the Environmental Protection Agency. (auth)

  4. An integrated engineering solution in treating tailings pond water (TPW)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Z. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    This presentation described the progress that has been made in the treatment of tailings pond water (TPW). Several treatment technologies were examined for their potential use. Any valid treatment methods must be technically practicable and economically feasible in treating TPW. An integrated TPW treatment process was proposed in this paper after reviewing recent published literature related to TPW treatment. The process was proposed based on knowledge and experience gained from municipal and other industrial water and wastewater treatment operations. This engineered treatment process consists of bioadsorption, bioflocculation, suspended sludge blanket filtration, clarification, ozonation, and coke assisted hybrid biodegradation. The proposed treatment process was aiming at environmental release and/or further reuse of the treated TPW. This proposed treatment process features the reuse of 2 waste materials in order to enhance the treatment efficiency, to increase financial feasibility, and to maximize environmental benefits of the treatment. tabs., figs.

  5. Intermediate Pond Sizes Contain the Highest Density, Richness, and Diversity of Pond-Breeding Amphibians

    Science.gov (United States)

    Semlitsch, Raymond D.; Peterman, William E.; Anderson, Thomas L.; Drake, Dana L.; Ousterhout, Brittany H.

    2015-01-01

    We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes. PMID:25906355

  6. Intermediate pond sizes contain the highest density, richness, and diversity of pond-breeding amphibians.

    Directory of Open Access Journals (Sweden)

    Raymond D Semlitsch

    Full Text Available We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes.

  7. Stabilization of heavy metals in fired clay brick incorporated with wastewater treatment plant sludge: Leaching analysis

    Science.gov (United States)

    Kadir, A. A.; Hassan, M. I. H.; Salim, N. S. A.; Sarani, N. A.; Ahmad, S.; Rahmat, N. A. I.

    2018-04-01

    Wastewater treatment sludge or known as sewage sludge is regarded as the residue and produced by the sedimentation of the suspended solid during treatment at the wastewater treatment plant. As such, this sludge was gained from the separation process of the liquids and solids. This sludge wastes has becomes national issues in recent years due to the increasing amount caused by population and industrialization growth in Malaysia. This research was conducted to fully utilize the sludge that rich in dangerous heavy metals and at the same time act as low cost alternative materials in brick manufacturing. The investigation includes determination of heavy metal concentration and chemical composition of the sludge, physical and mechanical properties. Wastewater treatment sludge samples were collected from wastewater treatment plant located in Johor, Malaysia. X-Ray Fluorescence was conducted to determine the heavy metals concentration of wastewater treatment sludge. Different percentage of sludges which are 0%, 1%, 5%, 10%, and 20%, has been incorporated into fired clay brick. The leachability of heavy metals in fired clay brick that incorporated with sludge were determined by using Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leachability Procedure (SPLP) that has been analyzed by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results show a possibility to stabilize the heavy metals in fired clay brick incorporated with wastewater treatment sludge. 20% of the sludge incorporated into the brick is the most suitable for building materials as it leached less heavy metals concentration and complying with USEPA standard.

  8. Bacteriophage enzymes for the prevention and treatment of bacterial infections: Stability and stabilization of the enzyme lysing Streptococcus pyogenes cells

    Energy Technology Data Exchange (ETDEWEB)

    Klyachko, N. L.; Dmitrieva, N. F.; Eshchina, A. S.; Ignatenko, O. V.; Filatova, L. Y.; Rainina, Evguenia I.; Kazarov, A. K.; Levashov, A. V.

    2008-06-01

    Recombinant, phage associated lytic enzyme Ply C capable to lyse streptococci of groups A and C was stabilized in the variety of the micelles containing compositions to improve the stability of the enzyme for further application in medicine. It was shown that, in the micellar polyelectrolyte composition M16, the enzyme retained its activity for 2 months; while in a buffer solution under the same conditions ((pH 6.3, room temperature), it completely lost its activity in 2 days

  9. Effect of Stabilization Heat Treatment on Time-Dependent Polarization Losses in Sintered Nd-Fe-B Permanent Magnets

    Directory of Open Access Journals (Sweden)

    Tuominen S.

    2013-01-01

    Full Text Available Some companies in the motor and generator industry utilizing sintered NdFeB magnets have adopted pre-ageing heat treatment in order to improve the stability of the magnets. The parameters of this stabilization heat treatment are based mainly on assumptions rather than on any published research results. In this work, the effects of pre-ageing treatment on the time-dependent polarization losses of two different types of commercial sintered NdFeB magnets were studied. The material showing the squarer J(H curve did not benefit from the pre-ageing treatment, since it seems to be stable under a certain critical temperature. In contrast, a stabilizing effect was observed in the material showing rounder J(H curve. After the stabilization heat treatment, the polarization of the magnets was found to be at lower level, but unchanged over a certain period of time. The length of this period depends on the temperature and the duration of the pre-ageing treatment. In addition, our analysis reveals that the stabilization heat treatment performed in an open circuit condition does not stabilize the magnet uniformly.

  10. Surface treatment influences electrochemical stability of cpTi exposed to mouthwashes

    Energy Technology Data Exchange (ETDEWEB)

    Beline, Thamara [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Garcia, Camila S. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Ogawa, Erika S. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Marques, Isabella S.V. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Matos, Adaias O. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Sukotjo, Cortino [Department of Restorative Dentistry, University of Illinois at Chicago, College of Dentistry, 801 S Paulina, Chicago, IL 60612 (United States); IBTN — Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Mathew, Mathew T. [IBTN — Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Department of Orthopedic Surgery, Rush University Medical Center, 1611 W Harrison, Chicago, IL 60612 (United States); and others

    2016-02-01

    The role of surface treatment on the electrochemical behavior of commercially pure titanium (cpTi) exposed to mouthwashes was tested. Seventy-five disks were divided into 15 groups according to surface treatment (machined, sandblasted with Al{sub 2}O{sub 3}, and acid etched) and electrolyte solution (artificial saliva — control, 0.12% chlorhexidine digluconate, 0.05% cetylpyridinium chloride, 0.2% sodium fluoride, and 1.5% hydrogen peroxide) (n = 5). Open-circuit-potential and electrochemical impedance spectroscopy were conducted at baseline and after 7 and 14 days of immersion in each solution. Potentiodynamic test and total weight loss of disks were performed after 14 days of immersion. Scanning electron microscopy, energy dispersive spectroscopy, white light interferometry and profilometry were conducted for surface characterization before and after the electrochemical tests. Sandblasting promoted the lowest polarization resistance (R{sub p}) (P < .0001) and the highest capacitance (CPE) (P < .006), corrosion current density (I{sub corr}) and corrosion rate (P < .0001). In contrast, acid etching increased R{sub p} and reduced CPE, independent to the mouthwash; while hydrogen peroxide reduced R{sub p} (P < .008) and increased I{sub corr} and corrosion rate (P < .0001). The highest CPE values were found for hydrogen peroxide and 0.2% sodium fluoride. Immersion for longer period improved the electrochemical stability of cpTi (P < .05). In conclusion, acid etching enhanced the electrochemical stability of cpTi. Hydrogen peroxide and sodium fluoride reduced the resistance to corrosion of cpTi, independent to the surface treatment. Chlorhexidine gluconate and cetylpyridinium chloride did not alter the corrosive behavior of cpTi. - Highlights: • Acid etching enhanced the electrochemical stability of cpTi. • Hydrogen peroxide and sodium fluoride reduced the corrosion resistance of cpTi. • Chlorhexidine gluconate and cetylpyridinium chloride can be safely used.

  11. Surface treatment influences electrochemical stability of cpTi exposed to mouthwashes

    International Nuclear Information System (INIS)

    Beline, Thamara; Garcia, Camila S.; Ogawa, Erika S.; Marques, Isabella S.V.; Matos, Adaias O.; Sukotjo, Cortino; Mathew, Mathew T.

    2016-01-01

    The role of surface treatment on the electrochemical behavior of commercially pure titanium (cpTi) exposed to mouthwashes was tested. Seventy-five disks were divided into 15 groups according to surface treatment (machined, sandblasted with Al 2 O 3 , and acid etched) and electrolyte solution (artificial saliva — control, 0.12% chlorhexidine digluconate, 0.05% cetylpyridinium chloride, 0.2% sodium fluoride, and 1.5% hydrogen peroxide) (n = 5). Open-circuit-potential and electrochemical impedance spectroscopy were conducted at baseline and after 7 and 14 days of immersion in each solution. Potentiodynamic test and total weight loss of disks were performed after 14 days of immersion. Scanning electron microscopy, energy dispersive spectroscopy, white light interferometry and profilometry were conducted for surface characterization before and after the electrochemical tests. Sandblasting promoted the lowest polarization resistance (R p ) (P < .0001) and the highest capacitance (CPE) (P < .006), corrosion current density (I corr ) and corrosion rate (P < .0001). In contrast, acid etching increased R p and reduced CPE, independent to the mouthwash; while hydrogen peroxide reduced R p (P < .008) and increased I corr and corrosion rate (P < .0001). The highest CPE values were found for hydrogen peroxide and 0.2% sodium fluoride. Immersion for longer period improved the electrochemical stability of cpTi (P < .05). In conclusion, acid etching enhanced the electrochemical stability of cpTi. Hydrogen peroxide and sodium fluoride reduced the resistance to corrosion of cpTi, independent to the surface treatment. Chlorhexidine gluconate and cetylpyridinium chloride did not alter the corrosive behavior of cpTi. - Highlights: • Acid etching enhanced the electrochemical stability of cpTi. • Hydrogen peroxide and sodium fluoride reduced the corrosion resistance of cpTi. • Chlorhexidine gluconate and cetylpyridinium chloride can be safely used.

  12. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  13. Stability of molar relationship after non-extraction Class II malocclusion treatment

    Directory of Open Access Journals (Sweden)

    Darwin Vaz de Lima

    2013-04-01

    Full Text Available OBJECTIVE: This study aimed to evaluate the stability of molar relationship after non-extraction treatment of Class II malocclusion. METHODS: The sample comprised 39 subjects (16 females, 23 males with initial Class II malocclusion treated with no extractions, using fixed appliances. Mean age at the beginning of treatment was 12.94 years, at the end of treatment was 15.14 years and at post-retention stage was 21.18 years. Mean treatment time was 2.19 years and mean time of post-treatment evaluation was 6.12 years. To verify the influence of the severity of initial Class II molar relationship in stability of molar relationship, the sample was divided into two groups, one presenting a ½-cusp or ¾-cusp Class II molar relationship, and the other with full-cusp Class II molar relationship. In dental casts from initial, final and postretention stages, molar, first and second premolars and canine relationships were measured. Data obtained were analyzed by dependent ANOVA, Tukey and Pearson's correlation tests, as well as independent t test between the two groups divided by severity of initial molar relationship. RESULTS: There was a non-statistically significant 0.12 mm relapse of molar relationship. The initial severity of Class II molar relationship was not correlated to relapse in the post-retention period. When compared, the two groups showed no difference in relapse of molar relationship. CONCLUSION: It was concluded that correction of Class II molar relationship is stable and initial severity does not influence relapse of molar relationship.

  14. Use of alum water treatment sludge to stabilize C and immobilize P and metals in composts.

    Science.gov (United States)

    Haynes, R J; Zhou, Y-F

    2015-09-01

    Alum water treatment sludge is composed of amorphous hydroxyl-Al, which has variable charge surfaces with a large Brunauer-Emmett-Teller (BET) surface area (103 m(-2) g(-1)) capable of specific adsorption of organic matter molecules, phosphate, and heavy metals. The effects of adding dried, ground, alum water treatment sludge (10% w/w) to the feedstock for composting municipal green waste alone, green waste plus poultry manure, or green waste plus biosolids were determined. Addition of water treatment sludge reduced water soluble C, microbial biomass C, CO2 evolution, extractable P, and extractable heavy metals during composting. The decrease in CO2 evolution (i.e., C sequestration) was greatest for poultry manure and least for biosolid composts. The effects of addition of water treatment sludge to mature green waste-based poultry manure and biosolid composts were also determined in a 24-week incubation experiment. The composts were either incubated alone or after addition to a soil. Extractable P and heavy metal concentrations were decreased by additions of water treatment sludge in all treatments, and CO2 evolution was also reduced from the poultry manure compost over the first 16-18 weeks. However, for biosolid compost, addition of water treatment sludge increased microbial biomass C and CO2 evolution rate over the entire 24-week incubation period. This was attributed to the greatly reduced extractable heavy metal concentrations (As, Cr, Cu, Pb, and Zn) present following addition of water treatment sludge, and thus increased microbial activity. It was concluded that addition of water treatment sludge reduces concentrations of extractable P and heavy metals in composts and that its effect on organic matter stabilization is much greater during the composting process than for mature compost because levels of easily decomposable organic matter are initially much higher in the feedstock than those in matured composts.

  15. STABILIZATION OF ACTIVE SLUDGE AFTER WASTEWATER TREATMENT CONTAMINATED BY PETROLEUM PRODUCTS

    Directory of Open Access Journals (Sweden)

    Olena Semenova

    2016-06-01

    Full Text Available Purpose: Biochemical purification of wastewater containing refined petroleum products takes place due to the oxidation of pollutants by active sludge organisms. As a result of this process the intense consumption of pollutants by active sludge and its growth occurs. Therefore, the possibility to use active sludge containing refined petroleum products after wastewater treatment requires its stabilization. Methods: In this work the oxidation by a 30% hydrogen peroxide solution was studied for its use as a stabilizer. Chemical oxidizers, including hydrogen peroxide destroy organic polymers retaining free water thus promoting water release from the structure of sludge particles. On the other hand remains of fine structured oxidized biopolymers can lead to filter clogging, that is, reduce moisture exchange of sludge. Results: The experiment was carried out to find out the correlation between the doses of hydrogen peroxide and the resistivity value of sludge filtration. Discussion: Stabilized active sludge can be used as a fuel for boiler rooms, which in its turn will reduce natural gas consumption for the enterprise needs.

  16. Technical proposal on the treatment of the influent of the Jose Antonio Alzate dam using aerobic pond system; Propuesta tecnica sobre el tratamiento del influente de la presa Jose Antonio Alzate a traves un sistema lagunar aerobio

    Energy Technology Data Exchange (ETDEWEB)

    Rosas de Alba, S.G. [Instituto Tecnologico de Toluca, Metepec, Estado de Mexico (Mexico)]. E-mail: sergio.rosas01@cfe.gob.mx; Barcelo Quintal, I.D.; Bussy Beaurain, A.L.; lopez Galvan, E. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco (Mexico)]. E-mail: idbq@correo.azc.uam.mx; leemp@correo.azc.uam.mx; loge@correo.azc.uam.mx

    2010-01-15

    In Mexico, discharge of waste water not treated is a common problem; this is the case of the Lerma river, where the original clean water contribution of the Almoloya-Lerma-San Bartolo timber-roof system, located in the valley of Toluca, State of Mexico, was replaced by the wastewater of the valley. The attempts to clean the water before their spill have been unfruitful and this has caused the present anaerobic conditions of the river in its entire route including the first receiving stage that is the Jose Antonio Alzate Dam (PJAA), becoming a potential source of diseases and a useless water body. In this work we evaluate the treatment efficiency of experimental waste water pond system. The treatment system was constructed with 5 screens which formed 6 internal channels and it had an operation in continuous form by 26 weeks, providing it with continuously polluted water of the Lerma river. We found that the efficiency of reduction of the organic matter reported as BOD, was 83% and it is carried out in the first channel after 7 days of hydraulic retention verifying that the channels do not work like lagoons in series. With the collected data we calculated, through the application of design equations, the factor of decay of organic matter k and the number of dispersion d, specific for the type of treatment and environmental conditions of the site. The required surface of treatment calculated to reach the efficiency of reduction of the DOD5 obtained experimentally. Thus, a surface of: 1 281.6 hectares distributed in 13 lagoons that can deal with a volume 8646.70 m{sup 3}/h was determined. Since this was a bigger surface than that of the dam, the available area was evaluated to make a proposal closer to reallity. [Spanish] La descarga de aguas residuales a los sistemas acuaticos, sin previo tratamiento, es un problema generalizado en Mexico; como es el caso del rio Lerma en donde se sustituyo el aporte de agua limpia proveniente del sistema lagunar Almoloya

  17. Arsenic in an alkaline AMD treatment sludge: Characterization and stability under prolonged anoxic conditions

    International Nuclear Information System (INIS)

    Beauchemin, Suzanne; Fiset, Jean-Francois; Poirier, Glenn; Ablett, James

    2010-01-01

    Lime treatment of acid mine drainage (AMD) generates large volumes of neutralization sludge that are often stored under water covers. The sludge consists mainly of calcite, gypsum and a widespread ferrihydrite-like Fe phase with several associated species of metal(loid) contaminants. The long-term stability of metal(loid)s in this chemically ill-defined material remains unknown. In this study, the stability and speciation of As in AMD sludge subjected to prolonged anoxic conditions is determined. The total As concentration in the sludge is 300 mg kg -1 . In the laboratory, three distinct water cover treatments were imposed on the sludge to induce different redox conditions (100%N 2 , 100%N 2 + glucose, 95%N 2 :5%H 2 ). These treatments were compared against a control of oxidized, water-saturated sludge. Electron micro-probe (EMP) analysis and spatially resolved synchrotron X-ray fluorescence (SXRF) results indicate that As is dominantly associated with Fe in the sludge. In all treatments and throughout the experiment, measured concentrations of dissolved As were less than 5 μg L -1 . Dissolved Mn concentration in the N 2 + glucose treatment increased significantly compared to other treatments. Manganese and As K-edge X-ray absorption near edge structure spectroscopy (XANES) analyses showed that Mn was the redox-active element in the solid-phase, while As was stable. Arsenic(V) was still the dominant species in all water-covered sludges after 9 months of anoxic treatments. In contrast, Mn(IV) in the original sludge was partially reduced into Mn(II) in all water-covered sludges. The effect was most pronounced in the N 2 + glucose treatment, suggesting microbial reduction. Micro-scale SXRF and XANES analysis of the treated sludge showed that Mn(II) accumulated in areas already enriched in Fe and As. Overall, the study shows that AMD sludges remain stable under prolonged anoxic conditions. External sources of chemical reductants or soluble C were needed to induce

  18. Monitoring the startup of a wet detention pond equipped with sand filters and sorption filters.

    Science.gov (United States)

    Vollertsen, J; Lange, K H; Pedersen, J; Hallager, P; Bruus, A; Laustsen, A; Bundesen, V W; Brix, H; Nielsen, A H; Nielsen, N H; Wium-Andersen, T; Hvitved-Jacobsen, T

    2009-01-01

    The startup of a wet retention pond designed for extended stormwater treatment was monitored by more than one year of continual measurement of hydraulic parameters, nutrients and quality parameters in the pond itself (pH, temperature, dissolved oxygen, turbidity). The data revealed that photosynthesis played an important role for dissolved oxygen and pH for most of the year. Another important observation was that the pond behaved more like a completely mixed reactor than like a plug flow reactor--even though the length to width ratio was as high as 4.5:1. The pond was equipped with sand filters and sorption filters whereby very good nutrient removal efficiencies were achieved.

  19. Technical manual for calculating cooling pond performance

    International Nuclear Information System (INIS)

    Krstulovich, S.F.

    1988-01-01

    This manual is produced in response to a growing number of requests for a technical aid to explain methods for simulating cooling pond performance. As such, it is a compilation of reports, charts and graphs developed through the years for use in analyzing situations. Section II contains a report summarizing the factors affecting cooling pond performance and lists statistical parameters used in developing performance simulations. Section III contains the graphs of simulated cooling pond performance on an hourly basis for various combinations of criteria (wind, solar, depth, air temperature and humidity) developed from the report in Section II. Section IV contains correspondence describing how to develop further data from the graphs in Section III, as well as mathematical models for the system of performance calculation. Section V contains the formulas used to simulate cooling pond performances in a cascade arrangement, such as the Fermilab Main Ring ponds. Section VI contains the calculations currently in use to evaluate the Main Ring pond performance based on current flows and Watts loadings. Section VII contains the overall site drawing of the Main Ring cooling ponds with thermal analysis and physical data

  20. CO₂ efflux from shrimp ponds in Indonesia.

    Directory of Open Access Journals (Sweden)

    Frida Sidik

    Full Text Available The conversion of mangrove forest to aquaculture ponds has been increasing in recent decades. One of major concerns of this habitat loss is the release of stored 'blue' carbon from mangrove soils to the atmosphere. In this study, we assessed carbon dioxide (CO₂ efflux from soil in intensive shrimp ponds in Bali, Indonesia. We measured CO₂ efflux from the floors and walls of shrimp ponds. Rates of CO₂ efflux within shrimp ponds were 4.37 kg CO₂ m⁻² y⁻¹ from the walls and 1.60 kg CO₂ m⁻² y⁻¹ from the floors. Combining our findings with published data of aquaculture land use in Indonesia, we estimated that shrimp ponds in this region result in CO₂ emissions to the atmosphere between 5.76 and 13.95 Tg y⁻¹. The results indicate that conversion of mangrove forests to aquaculture ponds contributes to greenhouse gas emissions that are comparable to peat forest conversion to other land uses in Indonesia. Higher magnitudes of CO₂ emission may be released to atmosphere where ponds are constructed in newly cleared mangrove forests. This study indicates the need for incentives that can meet the target of aquaculture industry without expanding the converted mangrove areas, which will lead to increased CO₂ released to atmosphere.

  1. CO₂ efflux from shrimp ponds in Indonesia.

    Science.gov (United States)

    Sidik, Frida; Lovelock, Catherine E

    2013-01-01

    The conversion of mangrove forest to aquaculture ponds has been increasing in recent decades. One of major concerns of this habitat loss is the release of stored 'blue' carbon from mangrove soils to the atmosphere. In this study, we assessed carbon dioxide (CO₂) efflux from soil in intensive shrimp ponds in Bali, Indonesia. We measured CO₂ efflux from the floors and walls of shrimp ponds. Rates of CO₂ efflux within shrimp ponds were 4.37 kg CO₂ m⁻² y⁻¹ from the walls and 1.60 kg CO₂ m⁻² y⁻¹ from the floors. Combining our findings with published data of aquaculture land use in Indonesia, we estimated that shrimp ponds in this region result in CO₂ emissions to the atmosphere between 5.76 and 13.95 Tg y⁻¹. The results indicate that conversion of mangrove forests to aquaculture ponds contributes to greenhouse gas emissions that are comparable to peat forest conversion to other land uses in Indonesia. Higher magnitudes of CO₂ emission may be released to atmosphere where ponds are constructed in newly cleared mangrove forests. This study indicates the need for incentives that can meet the target of aquaculture industry without expanding the converted mangrove areas, which will lead to increased CO₂ released to atmosphere.

  2. Properties of geopolymer binders prepared from milled pond ash

    Directory of Open Access Journals (Sweden)

    J. Temuujin

    2017-09-01

    Full Text Available Alkali-activated materials were prepared from pond ash from the Darkhan city (Mongolia thermal power station. This ash contains about 60 wt % X-ray amorphous material in addition to quartz, mullite, hematite and magnesioferrite, and presents significant storage problems since it is accumulating in large amounts and is a hazardous waste, containing 90–100 ppm of the heavy metals As, Pb and Cr, and about 800 ppm Sr. Alkali-activated materials synthesized from the as-received pond ash achieved compressive strengths of only 3.25 MPa. Reduction of the particle size by mechanical milling for up to 30 min progressively increases the compressive strength of the resulting alkali-activated geopolymer up to 15.4 MPa. Leaching tests indicate that the combination of milling and alkali treatment does not cause the release of the hazardous heavy metals from the product, making it suitable for construction applications.

  3. Treatment of invasive fungal infections: stability of voriconazole infusion solutions in PVC bags

    Directory of Open Access Journals (Sweden)

    Andréa I.H. Adams

    Full Text Available Voriconazole is a novel broad-spectrum antifungal drug, employed in the treatment of invasive fungal infections, and represents an alternative to amphotericin B treatment. The manufacturer recommends that any unused reconstituted product should be stored at 2ºC to 8ºC, for no more than 24 h, but no recommendations about i.v. infusion solutions are given. Previous works have reported on the stability of voriconazole in polyolefin bags and just one in 5% dextrose polyvinyl chloride (PVC bags, at a 4 mg.mL-1 concentration. In this work, the stability of voriconazole as an i.v. infusion solution in 0.9% sodium chloride and in 5% dextrose, in PVC bags, at 0.5 mg.mL-1, stored at 4 ºC and at room temperature, protected from light, was evaluated. These infusion solutions were analyzed for a 21-day period. Chemical stability was evaluated by HPLC assay. Visual inspection was performed and pH of the solutions was measured. No color change or precipitation in the solutions was observed. The drug content remained above 90% for 11 days in 0.9% sodium chloride and for 9 days in 5% dextrose solutions. The i.v. infusion solutions stored at room temperature were not stable. At room temperature, the voriconazole content dropped down to 88.3 and 86.6%, in 0.9% sodium chloride or 5% dextrose solutions, respectively, two days after admixture. Assays performed at the end of the study suggest the sorption of voriconazole by the PVC bags. The results of this study allow cost-effective batch production in the hospital pharmacy.

  4. MMB4 DMS nanoparticle suspension formulation with enhanced stability for the treatment of nerve agent intoxication.

    Science.gov (United States)

    Dixon, Hong; Clark, Andrew P-Z; Cabell, Larry A; McDonough, Joe A

    2013-01-01

    Various oximes are currently fielded or under investigation in the United States and other countries as a component of autoinjector emergency treatment systems for organophosphate nerve agent chemical weapons. Bis-pyridinium oximes in general have greater efficacy against a broad spectrum of nerve agents, but they have poor stability due to hydrolytic degradation at elevated temperatures. 1,1'-Methylenebis-4-[(hydroxyimino)methyl]pyridinium dimethanesulfonate (MMB4 DMS) is a leading candidate for next-generation nerve agent treatment systems, because it is more stable than other bis-pyridinium oximes, but it still degrades quickly at temperatures often encountered during storage and field use. The primary goal is to increase the stability and shelf life of MMB4 while maintaining the desirable pharmacokinetic (PK) properties of the aqueous formulation. We have developed a formulation to be used in a phase 1 clinical trial consisting of MMB4 micro/nanoparticles suspended in cottonseed oil, a biocompatible vegetable oil. Through various milling techniques, the average particle size can be controlled from approximately 200 to 6000 nm to produce non-Newtonian formulations that are viscous enough to resist rapid particle sedimentation while remaining injectable at a range of concentrations from 5 to 400 mg/mL. The preliminary accelerated stability test shows that MMB4 in these formulations is stable for at least 2 years at temperatures up to 80°C. Preliminary preclinical in vivo studies have demonstrated that all concentrations and particle sizes have desirable PK properties, including high bioavailability and rapid absorption, which is critical to combat potent and fast-acting nerve agents.

  5. Successful treatment of groin pain syndrome in a pole-vault athlete with core stability exercise.

    Science.gov (United States)

    Dello Iacono, Antonio; Maffulli, Nicola; Laver, Lior; Padulo, Johnny

    2017-12-01

    The purpose of this case report was to present a case of groin pain in a pole vault athlete describing the biomechanical features of the injury`s mechanism, acute medical management, and its successful rehabilitation. A 22-year-old professional pole-vaulter sustained an injury during a regular training session. The athlete reported significant left lower abdominal and left proximal adductor discomfort in all activities, including basic trunk motion when moving in bed, sit to stand, and walking, and was unable to return to the regular training. Clinical evaluation and imaging studies addressed the injury to a case of adductor-related groin pain associated with pubic symphysis degeneration. Treatment consisted of an exercise-based therapeutic protocol based on trunk and core muscle strengthening and stability program, with progressive motor and functional demands. Significant improvements in the overall clinical findings and functional outcomes were reported after 52 days of intervention when the athletes returned to his full athletic activity. These results suggest that an appropriate rehabilitation program, focused on trunk and core musculature stability exercise addressing to sport-related specific demands, should be considered as an optimal conservative method in the multidisciplinary approach for treatment of groin pain and prior to any surgical intervention.

  6. A solidification/stabilization process for wastewater treatment sludge from a primary copper smelter

    Directory of Open Access Journals (Sweden)

    Ivšić-Bajčeta Dragana

    2013-01-01

    Full Text Available Wastewater treatment sludge from primary copper smelter is characterized as hazardous waste that requires treatment prior disposal due to significant amount of heavy metals and arsenic. The aim of the presented study was to investigate the feasibility and the effectiveness of solidification/stabilization process of the sludge using fly ash and lime as binders. The effectiveness of the process was evaluated by Unconfined Compressive Strength (UCS testing, leaching tests (EN 12457-4 and Toxicity Characteristic Leaching Procedure (TCLP and Acid Neutralization Capacity (ANC test. All samples reached target UCS of 0.35 MPa. Calcium to silicon concentration ratio (cCa/cSi, determined by X-Ray Fluorescence (XRF analysis, was identified as main factor governing strength development. Inductively coupled plasma-optical emission spectrometry (ICP-OES analyses of solutions after leaching tests showed excellent stabilization of Cu, Ni, Pb and Zn (above 99 % and arsenic (above 90 % in samples with high Ca(OH2 content. Results of ANC test indicated that buffering capacity of solidified material linearly depended on Ca concentration in FA and lime. Sample with 20 % of binder heaving 50 % of FA and 50 % of lime met all requirements to be safely disposed. [Projekat Ministarstva nauke Republike Srbije, br. 34033

  7. STABILIZATION OF DRY SLUDGE OF LIQUID WASTE OF LEATHER TREATMENT BY USING FLY ASH

    Directory of Open Access Journals (Sweden)

    Cahya Widiyati

    2010-06-01

    Full Text Available The experiment of solidification of dry sludge of liquid waste of leather treatment are containing chrome (Cr by using fly ash has been done.  The experiment objective are immobilize Cr in the solid waste by using pozzoland cement was made of fly ash in order to stable in the repository.  The experiment were carried out by solidification of solid waste are containing total chrome of 1480.5 mg/kg sum of 2 - 10 weight % of (water + pozzoland cement by using pozzoland cement was made from the mixture of fly ash and calcite were burned at 1000 oC temperature for 2 hours.  The characterization of the solid composite of stabilization result consist of the compressive strength test and the leaching test by American Nuclear Society (ANS-16.1 method.  The experiment result were shown that pozzoland cement  can binding solid waste sum of 10 weight % of (water + pozzoland cement became the composite of waste concrete with the compressive strength of 577 ton/m2 and the chrome leaching test for 14 days of 0.059 mg/l.  The composite of waste concrete according to Bapedal rule for solidification of toxic waste with minimum compressive strength of 10 ton/m2 and maximum leached chrome of 5 mg/L.   Keywords: stabilization, solid waste, leather treatment, fly ash.

  8. Thermal stability and structural changes during heat treatment of nanostructured Al2024 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Enayati, M.H. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)], E-mail: ena78@cc.iut.ac.ir; Abbasi, M.H.; Karimzadeh, F. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-06-10

    Thermal stability and structural changes during isothermal heat treatment of nanostructured Al2024 alloy prepared by mechanical milling (MM) were investigated. Al2024 powders were subjected to high-energy milling for various times to produce nanostructured alloy. Nanostructured Al2024 alloy was subsequently annealed at 150-550 deg. C for 1-3 h under argon atmosphere. The as-milled and annealed powders were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that after 30 h of milling, an Al-Cu-Mg supersaturated solid solution with a grain size of 30 nm was obtained. This structure was then isothermally heat-treated at various temperatures for different times. The CuAl{sub 2} and CuMgAl{sub 2} precipitates formed after heat treatment at T < 350 deg. C. In contrast to CuAl{sub 2} phase, CuMgAl{sub 2} precipitates disappeared on XRD traces taken after annealing at temperatures higher than 350 deg. C. Investigation of grain growth kinetics showed that nanostructured Al2024 had high thermal stability so that Al grain size remained in nanosized scale (about 70 nm) even after heating at 550 deg. C for 3 h. The value of grain growth exponent and activation energy at different annealing temperatures were obtained and discussed in terms of solute and second phase drag effects.

  9. Floristics of ephemeral ponds in east-central Texas

    Science.gov (United States)

    Barbara R. MacRoberts; Michael H. MacRoberts; D. Craig Rudolph; David W. Peterson

    2014-01-01

    Beginning in 2009, we surveyed the vegetation of ephemeral ponds in Sabine and Nacogdoches counties in east-central Texas. These ponds are shallow and flat-bottomed, with a small but distinct flora dominated by grasses (Poaceae) and sedges (Cyperaceae). The floras of these ponds are most similar to those of flatwoods ponds located on the lower coastal plain. Once more...

  10. Microbial survey of fish ponds and mineral composition of Clarias ...

    African Journals Online (AJOL)

    This work reports on the microbial composition of stagnant fish ponds and mineral & metal composition of Clarias gariepinus from the fish ponds in Ilorin, Kwara State, Nigeria. The fishes apparently thrived well in the fish ponds. Microbiological analysis of the different fish ponds as well as the mineral composition of the fish ...

  11. Stability assessment of gas mixtures containing monoterpenes in varying cylinder materials and treatments.

    Science.gov (United States)

    Rhoderick, George C; Lin, Janice

    2013-05-07

    Studies of climate change increasingly recognize the diverse influences exerted by monoterpenes in the atmosphere, including roles in particulates, ozone formation, and oxidizing potential. Measurements of key monoterpenes suggest atmospheric mole fractions ranging from low pmol/mol (parts-per-trillion; ppt) to nmol/mol (parts-per-billion; ppb), depending on location and compound. To accurately establish the mole fraction trends, assess the role of monoterpenes in atmospheric chemistry, and relate measurement records from many laboratories and researchers, it is essential to have good calibration standards. The feasibility of preparing well-characterized, stable gas cylinder standards for monoterpenes at the nmol/mol level was previously tested using treated (Aculife IV) aluminum gas cylinders at NIST. Results for 4 of the 11 monoterpenes, monitored versus an internal standard of benzene, indicated stability in these treated aluminum gas cylinders for over 6 months and projected long-term (years) stability. However, the mole fraction of the key monoterpene β-pinene decreased, while the mole fractions of α-pinene, d-limonene (R-(+)-limonene), p-cymene, and camphene (a terpene not present in the initial gas mixture) increased, indicating a chemical transformation of β-pinene to these species. A similar pattern of decreasing mole fraction was observed in α-pinene where growth of d-limonene, p-cymene, and camphene has been observed in treated gas cylinders prepared with a mixture of just α-pinene and benzene as the internal standard. The current research discusses the testing of other cylinders and treatments for the potential of long-term stability of monoterpenes in a gas mixture. In this current study, a similar pattern of decreasing mole fraction, although somewhat improved short-term stability, was observed for β-pinene and α-pinene, with growth of d-limonene, p-cymene, and camphene, in nickel-plated carbon steel cylinders. β-Pinene and α-pinene showed

  12. Stability of Class II treatment with the Bionator followed by fixed appliances.

    Science.gov (United States)

    Francisconi, Manoela Fávaro; Henriques, José Fernando Castanha; Janson, Guilherme; Freitas, Karina Maria Salvatore de; Santos, Patrícia Bittencourt Dutra dos

    2013-01-01

    This prospective study assessed the stability of Class II treatment with the Bionator, followed by fixed appliances, 10 years after treatment. The experimental group comprised 23 patients of both sexes (10 boys, 13 girls) at a mean initial age of 11.74 years (late mixed or early permanent dentitions), treated for a mean period of 3.55 years who were evaluated at three stages: initial (T1), final (T2) and long-term posttreatment (T3). A total of 69 lateral cephalograms were evaluated and 69 dental casts were measured using the PAR index. The difference between initial and final PAR indexes, the percentage of occlusal improvement obtained with therapy and the percentage of relapse were calculated, using the PAR index. The variables were compared by repeated measures analysis of variance (ANOVA) followed by Tukey tests. The significant improvement in apical base relationship, the palatal inclination of the maxillary incisors and the labial inclination of the mandibular incisors, and the significant improvement in molar relationship and reduction of overjet and overbite, obtained with treatment, remained stable in the long-term posttreatment period. There was also significant improvement in the occlusal relationships which remained stable in the long-term posttreatment period. The percentage of occlusal improvement obtained was of 81.78% and the percentage of relapse was of 4.90%. Treatment of Class II division 1 malocclusions with the Bionator associated with fixed appliances showed to be stable in the long-term posttreatment period.

  13. Solar pond for heating anaerobic digesters

    International Nuclear Information System (INIS)

    Song Kehui; Li Shensheng

    1991-10-01

    A theoretical analysis and numerical results calculated for solar pond heating anaerobic digesters in Beijing area in China are presented. The effect of temperature rise is evident and rather steady. 3 refs, 1 fig., 1 tab

  14. Accumulation of Pollutants in Highway Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    -dimensional flow is described with a numerical CFD model. The particulate matter is analysed for grain size distributions, settling velocity distributions and corresponding heavy metal and PAH concentration. Erosion/resuspension experiments for detention pond sediments are carried out in the laboratory...... with currents and waves. In general the study shows that the bulk of hydrocarbons, PAH's and heavy metals accumulate in detention pond sediments and the removal efficiency for particulate matter in the detention ponds is around 80 %. An important parameter for retention of particulate matter in Denmark...... of heavy metals and polycyclic aromatic hydrocarbons from an arbitrary detention pond to the natural environment. The present thesis is a part of a co-operation between the Danish Road Directorate (Vejdirektoratet) and Aalborg University and is founded in the Danish construction act for new highways...

  15. Surface treatment influences electrochemical stability of cpTi exposed to mouthwashes.

    Science.gov (United States)

    Beline, Thamara; Garcia, Camila S; Ogawa, Erika S; Marques, Isabella S V; Matos, Adaias O; Sukotjo, Cortino; Mathew, Mathew T; Mesquita, Marcelo F; Consani, Rafael X; Barão, Valentim A R

    2016-02-01

    The role of surface treatment on the electrochemical behavior of commercially pure titanium (cpTi) exposed to mouthwashes was tested. Seventy-five disks were divided into 15 groups according to surface treatment (machined, sand blasted with Al2O3, and acid etched) and electrolyte solution (artificial saliva — control, 0.12% chlorhexidine digluconate, 0.05% cetylpyridinium chloride, 0.2% sodium fluoride, and 1.5% hydrogen peroxide) (n = 5). Open-circuit-potential and electrochemical impedance spectroscopy were conducted at baseline and after 7 and 14 days of immersion in each solution. Potentiodynamic test and total weight loss of disks were performed after 14 days of immersion. Scanning electron microscopy, energy dispersive spectroscopy, white light interferometry and profilometry were conducted for surface characterization before and after the electrochemical tests. Sandblasting promoted the lowest polarization resistance (Rp) (P b .0001) and the highest capacitance (CPE) (P b .006), corrosion current density (Icorr) and corrosion rate (P b .0001). In contrast, acid etching increased Rp and reduced CPE, independent to the mouthwash; while hydrogen peroxide reduced Rp (P b .008) and increased Icorr and corrosion rate (P b .0001). The highest CPE values were found for hydrogen peroxide and 0.2% sodium fluoride. Immersion for longer period improved the electrochemical stability of cpTi (P b .05). In conclusion, acid etching enhanced the electrochemical stability of cpTi. Hydrogen peroxide and sodium fluoride reduced the resistance to corrosion of cpTi, independent to the surface treatment. Chlorhexidine gluconate and cetylpyridinium chloride did not alter the corrosive behavior of cpTi.

  16. Stability of orthodontic treatment outcome in relation to retention status: An 8-year follow-up.

    Science.gov (United States)

    Steinnes, Jeanett; Johnsen, Gunn; Kerosuo, Heidi

    2017-06-01

    Our aim was to evaluate the stability of orthodontic treatment outcome and retention status 7 or more years after active treatment in relation to posttreatment or postretention time, type of retention appliance, and duration of retainer use. The subjects were former patients who completed orthodontic treatment with fixed appliances from 2000 to 2007. The pretreatment eligibility criteria were anterior crowding of 4 mm or more in the maxilla or the mandible and Angle Class I or Class II sagittal molar relationship. Acceptable pretreatment and posttreatment dental casts were required. A total of 67 patients participated, 24 men and 43 women, with a mean age of 24.7 years (range, 20.0-50.0 years). All participants had a follow-up clinical examination, which included impressions for follow-up casts, and each completed a questionnaire. Data were obtained from pretreatment, posttreatment, and follow-up (T2) casts as well as from the patients' dental records. Treatment stability was evaluated with the peer assessment rating (PAR) index and Little's irregularity index. The participation rate was 64%. The average posttreatment time was 8.5 years (range, 7.0-11.0). All participants had received a retainer in the mandible, maxilla, or both after active treatment. At T2, the PAR score showed a mean relapse of 14%. The majority (78%) of participants still had a fixed retainer at T2 (retainer group), and 22% had been out of retention for at least 1 year (postretention group). The relapse according to the PAR did not differ significantly between participants with and without a retainer at T2. From posttreatment to T2, the irregularity of the mandibular incisors increased almost 3 times more in participants with no retainer in the mandible compared with those with an intact retainer at T2 (P = 0.001). In the maxilla, no corresponding difference was found. Our results suggest that occlusal relapse can be expected after active orthodontic treatment irrespective of long

  17. Wintertime Emissions from Produced Water Ponds

    Science.gov (United States)

    Evans, J.; Lyman, S.; Mansfield, M. L.

    2013-12-01

    Every year oil and gas drilling in the U.S. generates billions of barrels of produced water (water brought to the surface during oil or gas production). Efficiently disposing of produced water presents a constant financial challenge for producers. The most noticeable disposal method in eastern Utah's Uintah Basin is the use of evaporation ponds. There are 427 acres of produced water ponds in the Uintah Basin, and these were used to evaporate more than 5 million barrels of produced water in 2012, 6% of all produced water in the Basin. Ozone concentrations exceeding EPA standards have been observed in the Uintah Basin during winter inversion conditions, with daily maximum 8 hour average concentrations at some research sites exceeding 150 parts per billion. Produced water contains ozone-forming volatile organic compounds (VOC) which escape into the atmosphere as the water is evaporated, potentially contributing to air quality problems. No peer-reviewed study of VOC emissions from produced water ponds has been reported, and filling this gap is essential for the development of accurate emissions inventories for the Uintah Basin and other air sheds with oil and gas production. Methane, carbon dioxide, and VOC emissions were measured at three separate pond facilities in the Uintah Basin in February and March of 2013 using a dynamic flux chamber. Pond emissions vary with meteorological conditions, so measurements of VOC emissions were collected during winter to obtain data relevant to periods of high ozone production. Much of the pond area at evaporation facilities was frozen during the study period, but areas that actively received water from trucks remained unfrozen. These areas accounted for 99.2% of total emissions but only 9.5% of the total pond area on average. Ice and snow on frozen ponds served as a cap, prohibiting VOC from being emitted into the atmosphere. Emissions of benzene, toluene, and other aromatic VOCs averaged over 150 mg m-2 h-1 from unfrozen pond

  18. UHS, Ultimate Heat Sink Cooling Pond Analysis

    International Nuclear Information System (INIS)

    Codell, R.; Nuttle, W.K.

    1998-01-01

    1 - Description of program or function: Three programs model performance of an ultimate heat sink cooling pond. National Weather Service data is read and analyzed to predict periods of lowest cooling performance and highest evaporative loss. The data is compared to local site data for significant differences. Then the maximum pond temperature is predicted. Five programs model performance of an ultimate heat sink spray pond. The cooling performance, evaporative water loss, and drift water loss as a function of wind speed are estimated for a spray field. These estimates are used in conjunction with National Weather Service data to predict periods of lowest cooling performance and highest evaporative loss. This data is compared to local site data for significant differences. Then the maximum pond temperature is predicted. 2 - Method of solution: The transfer of heat and water vapor is modeled using an equilibrium temperature procedure for an UHS cooling pond. The UHS spray pond model considers heat, mass, and momentum transfer from a single water drop with the surrounding air, and modification of the surrounding air resulting from the heat, mass, and momentum transfer from many drops in different parts of a spray field. 3 - Restrictions on the complexity of the problem: The program SPRCO uses RANF, a uniform random number generator which is an intrinsic function on the CDC. All programs except COMET use the NAMELIST statement, which is non standard. Otherwise these programs conform to the ANSI Fortran 77 standard. The meteorological data scanning procedure requires tens of years of recorded data to be effective. The models and methods, provided as useful tool for UHS analyses of cooling ponds and spray ponds, are intended as guidelines only. Use of these methods does not automatically assure NRC approval, nor are they required procedures for nuclear-power-plant licensing

  19. Pond fractals in a tidal flat

    OpenAIRE

    Cael, B. B.; Bisson, Kelsey; Lambert, Bennett Spencer

    2015-01-01

    Studies over the past decade have reported power-law distributions for the areas of terrestrial lakes and Arctic melt ponds, as well as fractal relationships between their areas and coastlines. Here we report similar fractal structure of ponds in a tidal flat, thereby extending the spatial and temporal scales on which such phenomena have been observed in geophysical systems. Images taken during low tide of a tidal flat in Damariscotta, Maine, reveal a well-resolved power-law distribution of p...

  20. Endoscopic treatment with stabilized nonanimal hyaluronic acid/dextranomer gel is effective in vesicoureteral reflux associated with bladder dysfunction.

    Science.gov (United States)

    Läckgren, Göran; Sköldenberg, Erik; Stenberg, Arne

    2007-03-01

    Endoscopic injection of stabilized nonanimal hyaluronic acid/dextranomer gel is an established treatment for vesicoureteral reflux in children. We performed a subgroup analysis to assess this treatment in reflux associated with bladder dysfunction. Of 308 consecutive children treated endoscopically with stabilized nonanimal hyaluronic acid/dextranomer gel for dilating vesicoureteral reflux 54 were observed retrospectively to have bladder dysfunction. Initial followup consisted of voiding cystourethrogram at 3 and 12 months after injection, with positive response defined as reflux grade 0 or I. At 7 to 12 years following treatment patient charts were checked for urinary tract infections and bladder dysfunction, and a followup survey (postal questionnaire) was administered. A positive response to therapy (cure) was observed in 45 children (83%) after 1 to 3 endoscopic treatments. Concurrently, bladder dysfunction had resolved in 32 patients (59%). After the last stabilized nonanimal hyaluronic acid/dextranomer gel implantation 45 patients (83%) were free of urinary tract infections. Questionnaire results were similar to chart based findings. Stabilized nonanimal hyaluronic acid/dextranomer gel implantation was well tolerated, with no associated complications. Endoscopic treatment with stabilized nonanimal hyaluronic acid/dextranomer gel appears to be similarly effective in patients with vesicoureteral reflux with and without bladder dysfunction. These data indicate that bladder dysfunction should not be considered a contraindication to endoscopic treatment for reflux.

  1. Copper Toxicity of Four Different Aquaculture Ponds

    Directory of Open Access Journals (Sweden)

    Moshood Mustapha

    2016-11-01

    were done I triplicates. Copper concentrations ranged from 0.01 to 0.10 mg/L, alkalinity ranged from 105 to 245mg/L. Weeks 1 and 12 recorded the highest and lowest Cu2+ concentrations, while lowest and highest alkalinity were obtained in weeks 1 and 12 respectively in all the ponds. Temperature and pH ranged from 29.1 to 35.9°C and 6.35 to 8.03. The trend of copper concentrations in the ponds was Natural > Earthen > Concrete > Collapsible, with concentration slightly above the normal in the ponds. This could have come from the pipes used in delivering water to the pond, copper alloy nets and mesh used in the ponds, anti-fouling agents, algaecides, water source and fish meal. Effect of elevated copper was seen in the morphology and behavior of Clarias gariepinus which include slimy mucus on the skin, aggressive and uncoordinated swimming with the opercula flared, slow growth, reduced odor perception of food and water bubbles on the ponds. Copper should be regularly bio monitored to determine toxicity in fish.

  2. The role of mast cell stabilization in treatment of postoperative ileus: a pilot study.

    Science.gov (United States)

    The, Frans O; Buist, Marrije R; Lei, Aaltje; Bennink, Roelof J; Hofland, Jan; van den Wijngaard, René M; de Jonge, Wouter J; Boeckxstaens, Guy E

    2009-09-01

    Although postoperative ileus (POI) is considered multifactorial, intestinal inflammation resulting from manipulation-induced mast cell activation is recognized as an important pathophysiological mechanism. Therefore, mast cell stabilization may represent a new therapeutic approach to shortening POI. The aim of this paper was to study the effect of ketotifen, a mast cell stabilizer, on postoperative gastrointestinal transit in patients who underwent abdominal surgery. In this pilot study, 60 patients undergoing major abdominal surgery for gynecological malignancy with standardized anesthesia were randomized to treatment with ketotifen (4 or 12 mg) or placebo. Patients were treated for 6 days, starting 3 days before surgery. Gastric emptying of liquids, selected as a primary outcome parameter, was measured 24 h after surgery using scintigraphy. Secondary end points were (scintigraphically assessed) colonic transit, represented as geometrical center of activity (segment 1(cecum) to 7(stool)) and clinical parameters. Gastric retention 1 h after liquid intake was significantly reduced by 12 mg (median 3% (1-7), P=0.01), but not by 4 mg ketotifen (18% (3-45), P=0.6) compared with placebo (16% (5-75)). Twenty-four hour colonic transit in placebo was 0.8 (0.0-1.1) vs. 1.2 (0.2-1.4) colon segments in the 12 mg ketotifen group (P=0.07). Abdominal cramps were significantly relieved in patients treated with 12 mg ketotifen, whereas other clinical parameters were not affected. Ketotifen significantly improves gastric emptying after abdominal surgery and warrants further exploration of mast cell stabilizers as putative therapy for POI.

  3. Sludge accumulation pattern in an anaerobic pond under Mediterranean climatic conditions.

    Science.gov (United States)

    Papadopoulos, A; Parisopoulos, G; Papadopoulos, F; Karteris, A

    2003-02-01

    The main objective of this study was to observe the sludge accumulation pattern of an experimental, covered, anaerobic pond treating municipal wastewater under Mediterranean climatic conditions throughout a 2-year operational period (1999-2000) in order to form a seasonal sludge accumulation model which may be used to predict the required desludging time, not only of the particular anaerobic pond used in the study, but also for other types of anaerobic ponds and operational situations. The 4-m deep pond was supplied with pre-screened, untreated wastewater from the nearby treatment plant of Thessaloniki, Greece, initially at a flow rate of 120m3/day and later at a flow rate of 150m3/day. The influent characteristics were BOD5 441 mg O2/L, COD 942 mg O2/L and suspended solids (SS) 574 mg/L. BOD5, COD, and SS concentrations of the pond effluent were reduced by 50%, 53%, and 64%, respectively, in comparison with those of the influent. During the operational period, three distinctly different zones were seen to form within the anaerobic pond: The first zone, which formed at the bottom of the pond, consisted of inert, high-density sludge. The second zone, which formed above this, contained a high concentration of volatile (easily biodegradable) sludge. The third upper zone (supernatant), was a liquid layer low in suspended solids. The accumulation of sludge in the pond followed an annual sinusoidal pattern with high values during winter and low ones during summer due to the increased digestion rate. The maximum high-density sludge height observed was 0.7m, or 2% (14 m3) of the total pond volume. The maximum volatile sludge accumulation reached 3.1 m, or 53% (300 m3) of the pond volume. A seasonal sludge accumulation model, based on the sludge inflow and seasonal digestion rates, was used to simulate the annual fluctuation in accumulation rate for the local (Mediterranean type) climatic conditions. Monthly values of accumulation (or digestion) rate of sludge (K(AS)) were

  4. Combined heterogeneous Electro-Fenton and biological process for the treatment of stabilized landfill leachate.

    Science.gov (United States)

    Baiju, Archa; Gandhimathi, R; Ramesh, S T; Nidheesh, P V

    2018-03-15

    Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm 2 . Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments

    KAUST Repository

    Salas Villaseñor, Ana L.

    2014-06-01

    Thin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.

  6. Stability of opiates in hair fibers after exposure to cosmetic treatment.

    Science.gov (United States)

    Pötsch, L; Skopp, G

    1996-08-15

    The stability of opiates in clipped natural human hair was investigated. Hair fibers were incubated with defined solutions of morphine, codeine and dihydrocodeine (pH 7.4) until saturated. Original opiate-positive hair samples collected from drug addicts also were examined. Commercially available bleaching as well as perming formulas (Poly Blonde Ultra, Poly Lock; Henkel, Düsseldorf, Germany) were applied in vitro to the hair strands of both groups under investigation. After these treatments, the drug concentration had decreased for both bleaching and permanent waving. In the spiked hair, only 2-18% of the starting solution could be found after bleaching. About 20-30% of the drug substances could still be detected after perming. In the authentic hair samples, the drug levels of the formerly opiate positive hair fibers had also been reduced but distinct tendencies could not be observed.

  7. Skeletal stability of patients undergoing maxillomandibular advancement for treatment of obstructive sleep apnea.

    Science.gov (United States)

    Lee, Sang Hwa; Kaban, Leonard B; Lahey, Edward T

    2015-04-01

    To determine the long-term stability of maxillomandibular advancement (MMA) in patients with obstructive sleep apnea (OSA). This was a retrospective cohort study of patients who underwent MMA and genial tubercle advancement (GTA) for treatment of OSA. Patients were included if they 1) were older than 19 years; 2) had a confirmatory polysomnogram; 3) underwent a Le Fort I osteotomy, bilateral sagittal split osteotomies, and GTA; 4) had adequate radiographic documentation; and 5) at least 11 months of follow-up. Exclusion criteria included previous orthognathic or other maxillofacial surgery. Predictor variables were the presence of OSA treated by MMA, pre- and postoperative orthodontia or no orthodontia, length of follow-up, and magnitude of advancement. The outcome variable was the stability of MMA judged by clinical examination and cephalometric measurements. Standardized lateral cephalometric measurements were performed preoperatively (T0), immediately postoperatively (T1), and at the latest follow-up beyond 11 months (T2). Differences in cephalometric measurements were calculated between time points (T0 to T1 and T1 to T2) for the overall group and for patients who had orthodontia (group 1) and those who did not (group 2). A correlation analysis using length of follow-up and magnitude of advancement as predictor variables of stability was completed. For all analyses, a P value less than .05 was considered statistically significant. During the 9-year study period, 120 patients with OSA were evaluated and 112 had operative treatment; 25 patients specifically had MMA and GTA, met the inclusion criteria, and formed the study sample. The mean maxillary and mandibular advancements (T1 vs T0) were 9.48 mm (range, 1.6 to 15.2 mm) and 10.85 mm (range, 6.3 to 15.8 mm), respectively. From T1 to T2, no occlusal changes occurred. Changes in the subgroup analyses included a decrease in the angle formed by the sella, nasion, and A point (SNA) and the angle formed by the nasion

  8. Comparison of stability in the operative treatment of pelvic injuries in a finite element model.

    Science.gov (United States)

    Bodzay, Tamás; Flóris, István; Váradi, Károly

    2011-10-01

    The comparison of the stability of four surgical methods for the treatment of vertically and rotationally unstable type C pelvic ring injuries. We produced a type C pelvic ring injury (type Denis II fracture of the sacrum and symphysiolysis) on a finite element model, in the case of standing on both feet. We stabilized the symphysiolysis with a five-hole reconstruction plate; the sacrum fracture was fixed in the first experiment with two, two-hole reconstruction plates on the ventral surface, in the second one we applied dorsally the transsacral, narrow DC plate, in the third one with KFI-H plate, and in the last one with iliosacral screw. Finite element modeling was performed by the use of the ALGOR software. Not only bones and joints, but joints and mechanically important ligaments were modeled as well. We measured the shift between the two surfaces of the fracture gap, compared to the results of measurements accomplished on cadaver models. Larger shift could be elicited after transsacral plating than after direct plating. These results correspond to those of the parallel investigation of the bony ligamentous cadaver pelvis specimens. The shift values after KFI-H plating and iliosacral screw fixation are larger than after direct plating, but smaller than after transsacral plating. The tension created in the implants is less than the allowed values; therefore, the choice of operation should depend on the type of injury. The finite element model may be utilized for the comparison of different methods of osteosynthesis for the treatment of injuries described above. Due to several difficulties in investigations performed on cadaver specimens, this model has undoubted utility.

  9. Occlusal stability after Herbst treatment of patients with retrognathic and prognathic facial types : A pilot study.

    Science.gov (United States)

    Bock, Niko C; Gnandt, Erhard; Ruf, Sabine

    2016-05-01

    The purpose of this study was to assess and compare occlusal changes induced by Herbst treatment and the stability of these changes in patients with retrognathic and prognathic facial types. The sample comprised 11 retrognathic (SNA ≤76°, SNB ≤72°, ML/NSL ≥36°) and 10 prognathic (SNA ≥83°, SNB ≥80°, ML/NSL ≤32°) patients with Class II molar relationships of ≥0.5 cusp widths bilaterally or ≥1.0 cusp width unilaterally. Both groups involved similar distributions of skeletal maturity before treatment. Study parameters were assessed on casts reflecting the situations before treatment (T0), after Herbst treatment (T1), after multibracket treatment immediately following Herbst treatment (T2), and after a mean of 31.1 months of retention (T3). Sagittal molar relationships improved by 0.8 cusp widths in the retrognathic and by 0.7 cusp widths in the prognathic group during active treatment (T0-T2). Insignificant changes of ≤0,2 cusp widths were seen in both groups during retention (T2-T3). Overjet decreased by 8.6 mm in the retrognathic and by 5.5 mm in the prognathic group during T0-T2, and both groups showed clinically irrelevant amounts of relapse by 0.7 mm during T2-T3. Overbite improved by 1.2 mm in the retrognathic and by 2.5 mm in the prognathic group during T0-T2, reaching mean values of 1.0 mm or 1.4 mm by T2, which was followed by 0.2 mm or 1.1 mm of relapse during T2-T3. Treatment with a Herbst appliance seems to offer stable correction of the sagittal occlusal relationships in Class II patients with retrognathic or prognathic facial types, with the vertical changes being more pronounced in the prognathic cases.

  10. Stability of Class II treatment with the Bionator followed by fixed appliances

    Directory of Open Access Journals (Sweden)

    Manoela Favaro FRANCISCONI

    2013-12-01

    Full Text Available Objective: This prospective study assessed the stability of Class II treatment with the Bionator, followed by fixed appliances, 10 years after treatment. Material and Methods: The experimental group comprised 23 patients of both sexes (10 boys, 13 girls at a mean initial age of 11.74 years (late mixed or early permanent dentitions, treated for a mean period of 3.55 years who were evaluated at three stages: initial (T1, final (T2 and long-term posttreatment (T3. A total of 69 lateral cephalograms were evaluated and 69 dental casts were measured using the PAR index. The difference between initial and final PAR indexes, the percentage of occlusal improvement obtained with therapy and the percentage of relapse were calculated, using the PAR index. The variables were compared by repeated measures analysis of variance (ANOVA followed by Tukey tests. Results: The significant improvement in apical base relationship, the palatal inclination of the maxillary incisors and the labial inclination of the mandibular incisors, and the significant improvement in molar relationship and reduction of overjet and overbite, obtained with treatment, remained stable in the long-term posttreatment period. There was also significant improvement in the occlusal relationships which remained stable in the long-term posttreatment period. The percentage of occlusal improvement obtained was of 81.78% and the percentage of relapse was of 4.90%. Conclusions: Treatment of Class II division 1 malocclusions with the Bionator associated with fixed appliances showed to be stable in the long-term posttreatment period.

  11. A comparison between evaporation ponds and evaporation surfaces as a source of the concentrated salt brine for salt gradient maintenance at Tajoura solar pond

    International Nuclear Information System (INIS)

    Ramadan, Abdulghani M.; Agha, Khairy R.; Abughres, M.

    2012-01-01

    One of the main problems that negatively affect the operation of salt gradient solar ponds and influence its thermal stability is the maintenance of salt gradient profile. Evaporation pond (EP) is designed to generate the salt which lost upward salt diffusion from the lower convective zone (LCZ) of the solar pond. Another attractive method is the evaporation surface facility (ES). Regions with moderate to high precipitation favor Evaporation Surface over Evaporation Ponds. Dry climates will generally favor Evaporation Ponds for the brine re-concentration. In previous studies [1-3], the authors have shown that the (EP) of Tajoura's Experimental Solar Pond (TESP) is under sized and can provide only about 30% of the salt required by a Salt Gradient Solar Pond (SGSP). The anticipated size of (EP) was estimated and presented in those studies under different design conditions, including Summer, Autumn and Spring designs, while the winter design was excluded due to the low rates of net evaporation during the winter season. In addition, the results presented were predicted for the first three years of operation. The daily variations of brine concentration in the (EP) of (TESP) and those based on different designs were predicted and discussed under different scenarios. The quantities of brine provided by the evaporation pond and that required by SGSP were predicted for both cases of surface water flushing (fresh water and sea-water) under the different design conditions as shown in Table 1. This paper investigates the differences between (EP) and (ES) both as a source for salt brine generation by evaporation. The effect of (EP) depth on the area ratio and daily variations of salt concentrations for three years of operation is shown. Results show that evaporation can be a reasonable method for salt brine generation. Reducing the depth of (EP) improves the capability of (EP) for brine re-concentration. It also increases the (EP) surface area for the same quantity of

  12. Interactions of an insecticide with competition and pond drying in amphibian communities

    Science.gov (United States)

    Boone, M.D.; Semlitsch, R.D.

    2002-01-01

    Amphibian populations are often imbedded in agricultural landscapes. Therefore the potential for contamination of their habitat is considerable. Our study examined the effects of an insecticide (carbaryl, a neurotoxin), on larval amphibian communities experiencing natural stresses of competition for resources, predation, and pond drying. In a set of experimental ponds, tadpoles of three anuran species (southern leopard frog [Rana sphenocephala], plains leopard frog [R. blairi], and the Woodhouse's toad [Bufo woodhousii]) were added to 1000-L ponds containing leaf litter, plankton, two newts (Notophthalmus viridescens), and four overwintered green frog (R. clamitans) tadpoles. We manipulated the overall tadpole density (low or high), pond hydroperiod (constant or drying), and chemical exposure (0, 3.5, 5.0, or 7.0 mg/L carbaryl) of the ponds. We measured mass, time, and survival to metamorphosis to determine treatment effects. Carbaryl positively affected Woodhouse's toad survival, although it had a negligible effect on both leopard frog species. Tadpole density interacted with the chemical treatment: Proportionately more Woodhouse's toads survived to metamorphosis in high-density environments than in low-density or control environments. Greater survival may be an indirect effect of increased algal food resources from carbaryl exposure. Most newts lost mass over the course of the experiment, although ponds with drying hydroperiods and high anuran density were the least favorable environments. Overwintered green frogs exposed to carbaryl had longer larval periods on average than did green frogs in control ponds. Our study demonstrated that even sublethal, short-lived contaminants can alter natural communities in ways that cannot be predicted from simple, one-factor studies.

  13. A new treatment of capillarity to improve the stability of IMPES two-phase flow formulation

    KAUST Repository

    Kou, Jisheng

    2010-12-01

    In this paper, we present an efficient numerical method for two-phase immiscible flow in porous media with different capillarity pressures. In highly heterogeneous permeable media, the saturation is discontinuous due to different capillary pressure functions. One popular scheme is to split the system into a pressure and a saturation equation, and to apply IMplicit Pressure Explicit Saturation (IMPES) approach for time stepping. One disadvantage of IMPES is instability resulting from the explicit treatment for capillary pressure. To improve stability, the capillary pressure is usually incorporated in the saturation equation which gradients of saturation appear. This approach, however, does not apply to the case of different capillary pressure functions for multiple rock-types, because of the discontinuity of saturation across rock interfaces. In this paper, we present a new treatment of capillary pressure, which appears implicitly in the pressure equation. Using an approximation of capillary function, we substitute the implicit saturation equation into the pressure equation. The coupled pressure equation will be solved implicitly and followed by the explicit saturation equation. Five numerical examples are provided to demonstrate the advantages of our approach. Comparison shows that our proposed method is more efficient and stable than the classical IMPES approach. © 2010 Elsevier Ltd.

  14. Local Stability of AIDS Epidemic Model Through Treatment and Vertical Transmission with Time Delay

    Science.gov (United States)

    Novi W, Cascarilla; Lestari, Dwi

    2016-02-01

    This study aims to explain stability of the spread of AIDS through treatment and vertical transmission model. Human with HIV need a time to positively suffer AIDS. The existence of a time, human with HIV until positively suffer AIDS can be delayed for a time so that the model acquired is the model with time delay. The model form is a nonlinear differential equation with time delay, SIPTA (susceptible-infected-pre AIDS-treatment-AIDS). Based on SIPTA model analysis results the disease free equilibrium point and the endemic equilibrium point. The disease free equilibrium point with and without time delay are local asymptotically stable if the basic reproduction number is less than one. The endemic equilibrium point will be local asymptotically stable if the time delay is less than the critical value of delay, unstable if the time delay is more than the critical value of delay, and bifurcation occurs if the time delay is equal to the critical value of delay.

  15. Effects of silvicultural treatment on the stability of black pine plantations.

    Directory of Open Access Journals (Sweden)

    Paolo Cantiani

    2010-12-01

    each intervention on the mensurational and mechanical stability parameters (H/D ratio H/Ddom ratio, are being analyzed. The stability parameters of the pine forest after three interventions (H/D ratio, crown ratio, horizontal crown projection and eccentricity of the crown have been also analyzed on a sample of trees per thesis and compared with those of trees grown in absence of competition. Sampled trees were sorted per social class. Results proved that type, interval and intensity of thinning related to the age of intervention are the main determinants of a successful treatment. Thinnings from below increase individual stability over time only when also trees living in the main crop layer are being removed. The trials showed the improvement of stability parameters following the intermediate thinning applied at the age of 45. The thesis of heavy thinning had the best performance as for the awaited purpose. st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

  16. Effects of thermal treatment on mineralogy and heavy metal behavior in iron oxide stabilized air pollution control residues

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Bender-Koch, C.; Starckpoole, M. M.

    2000-01-01

    Stabilization of air pollution control residues by coprecipitation with ferrous iron and subsequent thermal treatment (at 600 and 900 °C) has been examined as a means to reduce heavy metal leaching and to improve product stability. Changes in mineralogy and metal binding were analyzed using various...... volatilized or destabilized with respect to leaching. Pb, in particular, exhibited increased reactivity following the formation of an ordered iron oxide structure at 900 °C. The thermal treatment had a positive effect on Cr release, which was reduced significantly at 900 °C in the presence of organic matter...

  17. Gas transfer velocities in small forested ponds

    Science.gov (United States)

    Holgerson, Meredith A.; Farr, Emily R.; Raymond, Peter A.

    2017-05-01

    Inland waters actively exchange gases with the atmosphere, and the gas exchange rate informs system biogeochemistry, ecology, and global carbon budgets. Gas exchange in medium- to large-sized lakes is largely regulated by wind; yet less is known about processes regulating gas transfer in small ponds where wind speeds are low. In this study, we determined the gas transfer velocity, k600, in four small (water temperature; however, the explanatory power was weak (R2 water bodies, we compiled direct measurements of k600 from 67 ponds and lakes worldwide. Our k600 estimates were within the range of estimates for other small ponds, and variability in k600 increased with lake size. However, the majority of studies were conducted on medium-sized lakes (0.01 to 1 km2), leaving small ponds and large lakes understudied. Overall, this study adds four small ponds to the existing body of research on gas transfer velocities from inland waters and highlights uncertainty in k600, with implications for calculating metabolism and carbon emissions in inland waters.

  18. Anterior Cruciate Ligament Tear: Reliability of MR Imaging to Predict Stability after Conservative Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hye Won; Ahn, Jin Hwan; Ahn, Joong Mo; Yoon, Young Cheol; Hong, Hyun Pyo; Yoo, So Young; Kim, Seon Woo [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2007-06-15

    The aim of this study is to evaluate the reliability of MR imaging to predict the stability of the torn anterior cruciate ligament (ACL) after complete recovery of the ligament's continuity. Twenty patients with 20 knee injuries (13 males and 7 females; age range, 20 54) were enrolled in the study. The inclusion criteria were a positive history of acute trauma, diagnosis of the ACL tear by both the physical examination and the MR imaging at the initial presentation, conservative treatment, complete recovery of the continuity of the ligament on the follow up (FU) MR images and availability of the KT-2000 measurements. Two radiologists, who worked in consensus, graded the MR findings with using a 3-point system for the signal intensity, sharpness, straightness and the thickness of the healed ligament. The insufficiency of ACL was categorized into three groups according to the KT-2000 measurements. The statistic correlations between the grades of the MR findings and the degrees of ACL insufficiency were analyzed using the Cochran-Mantel-Haenszel test (p < 0.05). The p-values for each category of the MR findings according to the different groups of the KT-2000 measurements were 0.9180 for the MR signal intensity, 1.0000 for sharpness, 0.5038 for straightness and 0.2950 for thickness of the ACL. The MR findings were not significantly different between the different KT-2000 groups. MR imaging itself is not a reliable examination to predict stability of the ACL rupture outcome, even when the MR images show an intact appearance of the ACL.

  19. Removal of organic micropollutants in waste stabilisation ponds: A review.

    Science.gov (United States)

    Gruchlik, Yolanta; Linge, Kathryn; Joll, Cynthia

    2018-01-15

    As climate change and water scarcity continue to be of concern, reuse of treated wastewater is an important water management strategy in many parts of the world, particularly in developing countries and remote communities. Many countries, especially in remote regional areas, use waste stabilisation ponds (WSPs) to treat domestic wastewater for a variety of end uses, including using the treated wastewater for irrigation of public spaces (e.g. parks and ovals) or for crop irrigation. Thus, it is vital that the resulting effluent meets the required quality for beneficial reuse. In this paper, both the performance of WSPs in the removal of organic micropollutants, and the mechanisms of removal, are reviewed. The performance of WSPs in the removal of organic micropollutants was found to be highly variable and influenced by many factors, such as the type and configuration of the ponds, the operational parameters of the treatment plant, the wastewater quality, environmental factors (e.g. sunlight, temperature, redox conditions and pH) and the characteristics of the pollutant. The removal of organic micropollutants from WSPs has been attributed to biodegradation, photodegradation and sorption processes, the majority of which occur in the initial treatment stages (e.g. in the anaerobic or facultative ponds). Out of the many hundreds of organic micropollutants identified in wastewater, only a limited number (40) have been studied in WSPs, with the majority of these pollutants being pharmaceuticals, personal care products and endocrine disrupting compounds. Thus, future research on the fate of organic micropollutants in WSPs should encompass a broader range of micropollutants and include emerging organic pollutants, such as illicit drugs and perfluorinated compounds. Further research is also needed on the formation and toxicity of transformation products from organic micropollutants in WSPs, since the transformation products of some organic micropollutants can be more toxic

  20. Physicochemical stability of a new topical timolol 0.5% gel formulation for the treatment of infant hemangioma.

    Science.gov (United States)

    Merino-Bohórquez, V; Casas, M; Caracuel, F; Cameán, M; Fernández-Anguita, M J; Ramírez-Soto, G; Lucero, M J

    2015-01-01

    Infant hemangioma (IH) is the most common tumor in infants, which affects 5-10% of white children. It is a tumor of vascular origin that appears in the first months of life. The indication for the treatment of the IH is not approved in the datasheet of the product, however it has been used in the infant hemangioma by topical administration as an alternative to oral propranolol, avoiding the main problems of the oral route (bradycardia and hypotension). The objective of this work is to study the physical and chemical (HPLC stability indicating method) stability of a 0.5% timolol gel for topical application during 60 days (considering the stability limit as 90% of initial concentration of timolol maleate). The gel was prepared with a polyacrylic acid derivative and the physical stability of the system was studied by visual control, rheological and mechanical characterization. The studied formulation guarantees the correct dose administering and stability after 60 days stored at 25 ± 2 °C and light protected (tube of aluminum). We have developed an easy topical gel for the treatment of infant hemangioma with physical and chemical stability higher than those provided by the majority of hospitals.

  1. Stabilizing Group Treatment for Complex Posttraumatic Stress Disorder Related to Childhood Abuse Based on Psycho-Education and Cognitive Behavioral Therapy: A Pilot Study

    Science.gov (United States)

    Dorrepaal, Ethy; Thomaes, Kathleen; Smit, Johannes H.; van Balkom, Anton J. L. M.; van Dyck, Richard; Veltman, Dick J.; Draijer, Nel

    2010-01-01

    Objective: This study tests a Stabilizing Group Treatment protocol, designed for the management of the long-term sequelae of child abuse, that is, Complex Posttraumatic Stress Disorder (Complex PTSD). Evidence-based treatment for this subgroup of PTSD patients is largely lacking. This stabilizing treatment aims at improving Complex PTSD using…

  2. Denaturation and Oxidative Stability of Hemp Seed (Cannabis sativa L.) Protein Isolate as Affected by Heat Treatment.

    Science.gov (United States)

    Raikos, Vassilios; Duthie, Garry; Ranawana, Viren

    2015-09-01

    The present study investigated the impact of heat treatments on the denaturation and oxidative stability of hemp seed protein during simulated gastrointestinal digestion (GID). Heat-denatured hemp protein isolate (HPI) solutions were prepared by heating HPI (2 mg/ml, pH 6.8) to 40, 60, 80 and 100 °C for 10 min. Heat-induced denaturation of the protein isolates was monitored by polyacrylamide gel electrophoresis. Heating HPI at temperatures above 80 °C significantly reduced solubility and led to the formation of large protein aggregates. The isolates were then subjected to in vitro GID and the oxidative stability of the generated peptides was investigated. Heating did not significantly affect the formation of oxidation products during GID. The results suggest that heat treatments should ideally remain below 80 °C if heat stability and solubility of HPI are to be preserved.

  3. Treatment compliance and effectiveness in complex PTSD patients with co-morbid personality disorder undergoing stabilizing cognitive behavioral group treatment: a preliminary study

    Directory of Open Access Journals (Sweden)

    Ethy Dorrepaal

    2013-11-01

    Full Text Available Background: In the empirical and clinical literature, complex posttraumatic stress disorder (PTSD and personality disorders (PDs are suggested to be predictive of drop-out or reduced treatment effectiveness in trauma-focused PTSD treatment. Objective: In this study, we aimed to investigate if personality characteristics would predict treatment compliance and effectiveness in stabilizing complex PTSD treatment. Method: In a randomized controlled trial on a 20-week stabilizing group cognitive behavioral treatment (CBT for child-abuse-related complex PTSD, we included 71 patients of whom 38 were randomized to a psycho-educational and cognitive behavioral stabilizing group treatment. We compared the patients with few PD symptoms (adaptive (N=14 with the non-adaptive patients (N=24 as revealed by a cluster analysis. Results: We found that non-adaptive patients compared to the adaptive patients showed very low drop-out rates. Both non-adaptive patients, classified with highly different personality profiles “withdrawn” and “aggressive,” were equally compliant. With regard to symptom reduction, we found no significant differences between subtypes. Post-hoc, patients with a PD showed lower drop-out rates and higher effect sizes in terms of complex PTSD severity, especially on domains that affect regulation and interpersonal problems. Conclusion: Contrary to our expectations, these preliminary findings indicate that this treatment is well tolerated by patients with a variety of personality pathology. Larger sample sizes are needed to study effectiveness for subgroups of complex PTSD patients.

  4. Valuing Multiple Benefits, and the Public Perception of SUDS Ponds

    Directory of Open Access Journals (Sweden)

    Joy Jarvie

    2017-02-01

    Full Text Available Understanding how the public perceive and value ponds is fundamental to appreciate the synergy between Sustainable urban Drainage (SUDS ponds and the multiple benefits they provide. This paper investigates this, through the application of a structured postal and online survey, for a case study area of Edinburgh, in the UK. It compares man-made ponds (including SUDS, and ponds with natural origins. The results from Whole Life Cost show that the benefits (based on Contingent Valuation exceed the CAPEX and OPEX costs for three of five artificial ponds studied. Benefits from natural (reference ponds exceed the replacement costs for a pond with the same surface area/catchment. This paper highlights the importance of monetising the multiple benefits from ponds.

  5. Sea Ice Melt Pond Data from the Canadian Arctic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains observations of albedo, depth, and physical characteristics of melt ponds on sea ice, taken during the summer of 1994. The melt ponds studied...

  6. Comparison of solar pond concepts for electrical power generation

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, K; Duffy, J B; Harling, O K; Knutsen, C A; McKinnon, M A; Peterson, P L; Shaffer, L H; Styris, D L; Zaworski, R

    1975-10-01

    The objectives of this study were to: (1) Identify the various solar pond concepts for electric power generation, including but not limited to: (a) nonconvective salt gradient solar pond, (b) ponds with various plastic or other membranes at suitable locations to minimize or eliminate convection, (c) ponds which are totally or partially gelled to reduce or eliminate convection, and (d) shallow convecting ponds; (2) analyze and compare the performance of these various concepts; and (3) estimate the pond cost and overall power plant system cost for each concept assuming the nonconvective gradient salt pond as the base case. The approach includes a preliminary design of several power plant systems based on solar pond concepts, and performance and economic evaluation based on these preliminary designs. (WDM)

  7. Bioaccumulation of heavy metals in two wet retention ponds

    DEFF Research Database (Denmark)

    Søberg, Laila C.; Vollertsen, Jes; Blecken, Godecke-Tobias

    2016-01-01

    Metal accumulation in stormwater ponds may contaminate the inhabiting fauna, thus jeopardizing their ecosystem servicing function. We evaluated bioaccumulation of metals in natural fauna and caged mussel indicator organisms in two wet retention ponds. Mussel cages were distributed throughout the ...

  8. Modelling the fate of organic micropollutants in stormwater ponds

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Eriksson, Eva; Ledin, Anna

    2011-01-01

    Urban water managers need to estimate the potential removal of organic micropollutants (MP) in stormwater treatment systems to support MP pollution control strategies. This study documents how the potential removal of organic MP in stormwater treatment systems can be quantified by using multimedia...... models. The fate of four different MP in a stormwater retention pond was simulated by applying two steady-state multimedia fate models (EPI Suite and SimpleBox) commonly applied in chemical risk assessment and a dynamic multimedia fate model (Stormwater Treatment Unit Model for Micro Pollutants — STUMP...... substance inherent properties to calculate MP fate but differ in their ability to represent the small physical scale and high temporal variability of stormwater treatment systems. Therefore the three models generate different results. A Global Sensitivity Analysis (GSA) highlighted that settling...

  9. Effect of heat treatment and packaging systems on the stability of fish sausage

    Directory of Open Access Journals (Sweden)

    Bruna Rafaela Dallabona

    2013-12-01

    Full Text Available The purpose of this study was to evaluate the physicochemical and microbiological stability of sausages produced from mechanically separated fish meat (MSM obtained from Nile tilapia filleting residues. Different heat treatments (pasteurization or smoking and packaging systems (conventional or vacuum were used. The sausages were characterized for chemical composition, weight loss, water activity, instrumental texture and sensorial analysis. Additionally, microbiological analysis, instrumental color, pH, thiobarbituric acid reactive substances (TBARS and total volatile base nitrogen (TVB-N were assessed during storage. No presence of Escherichia coli, Salmonella sp. or coagulase-positive Staphylococcus was detected; however, the psychrotrophic count in pasteurized sausages exceeded the limits allowed for consumption. pH and lipid oxidation speed (TBARS values were reduced when vacuum packaging was used. Volatile nitrogenous bases remained virtually constant during the storage period, and higher values were observed in smoked products. Pasteurized sausages remain stable for 10 and 15 days in conventional and vacuum packages, respectively, and smoked sausages remain stable for 25 and 45 days in conventional and vacuum packages, respectively.

  10. The concept of ecological succession applied to phytoplankton over four consecutive years in five ponds featuring a salinity gradient

    Science.gov (United States)

    Khemakhem, Hajer; Elloumi, Jannet; Moussa, Mahmoud; Aleya, Lotfi; Ayadi, Habib

    2010-06-01

    The distribution of phytoplankton abundance, biomass and species composition coupled with environmental factors and metazooplankton was studied relatively intensively and over a period of four consecutive years in five ponds featuring a gradient of increasing salinity from near to that of sea water to a nine-fold concentration from 2000 to 2003. The results indicate that the physical characteristics of the water (temperature and salinity) were quite similar over the years. Nutrients, which were concentrated in pond A1, decreased with increases in salt concentration. The composition of the phytoplankton community showed strong seasonality. Diatoms dominated in the first ponds A1, A16 and C2-1, followed by dinoflagellates. Chlorophyceae dominated the phytoplankton community in the hypersaline ponds M2 and TS. Cyanobacteriae were relatively abundant in ponds M2 and TS. The highest phytoplankton density and biomass were found in the ponds with the highest salinity due to the proliferation of Dunaliella salina (Chlorophyta: Volvocales). The inter-annual study of phytoplankton succession in the Sfax solar salterns showed slight differences among the years of study due to the stability of the environmental conditions. Phytoplankton communities were permanently primitive, stage 1 - structured as they failed to build complexity because of salt stress which operates for longer and above any other variables. This reduced frequency of disturbance to the existing course of regulation, allowed the community to "mature" from its "primitive" state, rather than experience frequent structural setbacks.

  11. production of tilapia rendalli in weedy ponds receiving no external ...

    African Journals Online (AJOL)

    1993-07-01

    Jul 1, 1993 ... ABSTRACT. T ilapia rendalli were stocked at a rate of one fish per square metre in six replicate 200 m2 ponds and grown for 104 days. At stocking, three ponds were weed~free while three ponds had an average weed cover of 65.5%. The weed-free ponds received locally» available inputs at rates ...

  12. A randomized controlled study of early headgear treatment on occlusal stability--a 13 year follow-up.

    Science.gov (United States)

    Krusinskiene, Viktorija; Kiuttu, Päivi; Julku, Johanna; Silvola, Anna-Sofia; Kantomaa, Tuomo; Pirttiniemi, Pertti

    2008-08-01

    The purpose of this investigation was to assess the long-term occlusal stability in a group treated early with headgear (HG) compared with a control group. The total study group comprised 68 children (40 males and 28 females) aged 7.6 years (standard deviation 0.3), randomly divided into two groups of equal size. In the first group, HG treatment was initiated immediately, while in the control group only minor interceptive procedures were performed during the follow-up period. Fixed appliance treatment, if needed, including extraction of permanent teeth due to crowding, was undertaken after the completion of early treatment. The records were available from the start of the early treatment and at follow-up after 2, 4, 8, and 13 years. The US-weighted Peer Assessment Rating (PAR) Index, graded according to the severity of malocclusion, was used to evaluate occlusal stability. Little's Irregularity Index (LII)and intercanine distance in the lower arch were measured at all time periods. The Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) scores was used for evaluation of dental aesthetics at the last follow-up. Parametric tests were applied for statistical analyses, except for the evaluation of aesthetics, where a non-parametric test was used. No significant differences were found when long-term stability between the HG and control groups was evaluated at the 13 year follow-up. Lower PAR scores were observed in patients treated without extraction of teeth. A greater irregularity in lower incisor alignment before treatment was found in subjects later treated with extractions. The findings of this study seem to suggest that treatment timing has only a minor influence on stability.

  13. Percolation blockage: A process that enables melt pond formation on first year Arctic sea ice

    Science.gov (United States)

    Polashenski, Chris; Golden, Kenneth M.; Perovich, Donald K.; Skyllingstad, Eric; Arnsten, Alexandra; Stwertka, Carolyn; Wright, Nicholas

    2017-01-01

    Melt pond formation atop Arctic sea ice is a primary control of shortwave energy balance in the Arctic Ocean. During late spring and summer, the ponds determine sea ice albedo and how much solar radiation is transmitted into the upper ocean through the sea ice. The initial formation of ponds requires that melt water be retained above sea level on the ice surface. Both theory and observations, however, show that first year sea ice is so highly porous prior to the formation of melt ponds that multiday retention of water above hydraulic equilibrium should not be possible. Here we present results of percolation experiments that identify and directly demonstrate a mechanism allowing melt pond formation. The infiltration of fresh water into the pore structure of sea ice is responsible for blocking percolation pathways with ice, sealing the ice against water percolation, and allowing water to pool above sea level. We demonstrate that this mechanism is dependent on fresh water availability, known to be predominantly from snowmelt, and ice temperature at melt onset. We argue that the blockage process has the potential to exert significant control over interannual variability in ice albedo. Finally, we suggest that incorporating the mechanism into models would enhance their physical realism. Full treatment would be complex. We provide a simple temperature threshold-based scheme that may be used to incorporate percolation blockage behavior into existing model frameworks.

  14. [Stability of orthodontic-maxillofacial surgical treatment of anterior open bite deformities

    NARCIS (Netherlands)

    Hoppenreijs, T.J.M.; Freihofer, H.P.M.; Stoelinga, P.J.W.; Tuinzing, D.B.

    2001-01-01

    A sample of 267 patients with maxillary hyperplasia, a Class I or Class II occlusion and anterior open bite, collected from three different institutions, was analysed regarding stability after Le Fort I intrusion osteotomies or bimaxillary osteotomies. Skeletal and dento-alveolar stability of the

  15. Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment.

    Science.gov (United States)

    Clancy, Tara M; Snyder, Kathryn V; Reddy, Raghav; Lanzirotti, Antonio; Amrose, Susan E; Raskin, Lutgarde; Hayes, Kim F

    2015-12-30

    Cement stabilization of arsenic-bearing wastes is recommended to limit arsenic release from wastes following disposal. Such stabilization has been demonstrated to reduce the arsenic concentration in the Toxicity Characteristic Leaching Procedure (TCLP), which regulates landfill disposal of arsenic waste. However, few studies have evaluated leaching from actual wastes under conditions similar to ultimate disposal environments. In this study, land disposal in areas where flooding is likely was simulated to test arsenic release from cement stabilized arsenic-bearing iron oxide wastes. After 406 days submersed in chemically simulated rainwater, wastes. Presenting the first characterization of cement stabilized waste using μXRF, these results revealed the majority of arsenic in cement stabilized waste remained associated with iron. This distribution of arsenic differed from previous observations of calcium-arsenic solid phases when arsenic salts were stabilized with cement, illustrating that the initial waste form influences the stabilized form. Overall, cement stabilization is effective for arsenic-bearing wastes when acidic conditions can be avoided. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Mixed culture of fishes in seasonal ponds through fertilization and feeding

    OpenAIRE

    Hossain, M.A.; Ahmed, M.; Kamal, M.; Islam, M.N.

    1997-01-01

    A study on mixed culture of mirror carp (Cyprinus carpio Lin.), tilapia (Oreochromis niloticus Lin.), silver carp (Hypophthalmicthys molitrix Val.) and Thai sharpunti (Puntius gonionotus Bleeker) in the ratio of 1:2:2:5 was conducted in 12 seasonal mini ponds (30 m² each) for 105 days. There were six treatments each with two replicates and each pond was stocked with a total of 100 fishes. Rice bran and mustard oil cake were used as supplemental feed either in combination or alone in presen...

  17. Enhancing Nitrification at Low Temperature with Zeolite in a Mining Operations Retention Pond

    OpenAIRE

    Miazga-Rodriguez, Misha; Han, Sukkyun; Yakiwchuk, Brian; Wei, Kai; English, Colleen; Bourn, Steven; Bohnert, Seth; Stein, Lisa Y.

    2012-01-01

    Ammonium nitrate explosives are used in mining operations at Diavik Diamond Mines Inc. in the Northwest Territories, Canada. Residual nitrogen is washed into the mine pit and piped to a nearby retention pond where its removal is accomplished by microbial activity prior to a final water treatment step and release into the sub-Arctic lake, Lac de Gras. Microbial removal of ammonium in the retention pond is rapid during the brief ice-free summer, but often slows under ice cover that persists up ...

  18. Pond fractals in a tidal flat.

    Science.gov (United States)

    Cael, B B; Lambert, Bennett; Bisson, Kelsey

    2015-11-01

    Studies over the past decade have reported power-law distributions for the areas of terrestrial lakes and Arctic melt ponds, as well as fractal relationships between their areas and coastlines. Here we report similar fractal structure of ponds in a tidal flat, thereby extending the spatial and temporal scales on which such phenomena have been observed in geophysical systems. Images taken during low tide of a tidal flat in Damariscotta, Maine, reveal a well-resolved power-law distribution of pond sizes over three orders of magnitude with a consistent fractal area-perimeter relationship. The data are consistent with the predictions of percolation theory for unscreened perimeters and scale-free cluster size distributions and are robust to alterations of the image processing procedure. The small spatial and temporal scales of these data suggest this easily observable system may serve as a useful model for investigating the evolution of pond geometries, while emphasizing the generality of fractal behavior in geophysical surfaces.

  19. Aquatic Habitats: Exploring Desktop Ponds. Teacher's Guide.

    Science.gov (United States)

    Barrett, Katharine; Willard, Carolyn

    This book, for grades 2-6, is designed to provide students with a highly motivating and unique opportunity to investigate an aquatic habitat. Students set up, observe, study, and reflect upon their own "desktop ponds." Accessible plants and small animals used in these activities include Elodea, Tubifex worms, snails, mosquito larvae, and fish.…

  20. Phytobenthic Communities in Earthen Ponds {at Makoba

    African Journals Online (AJOL)

    These results support the use of natural ponds at Makoba for aquaculture, using natural/live food sources. Manipulation of some environmental parameters could further enhance availability of natural food for fry and fingerlings. For example, once salinity is lowered, mass production of live food for fish fry and fingerlings ...

  1. Environmental impact of seasonal integrated aquaculture ponds ...

    African Journals Online (AJOL)

    The environmental impact of fingerponds, particularly on hydrology and biodiversity, was low, although land-use changes at the immediate site where the ponds were dug had direct impacts. Whereas this study was based on short-term monitoring of experimental fingerponds, scaling up of these systems may increase their ...

  2. Pond fractals in a tidal flat

    Science.gov (United States)

    Cael, B. B.; Lambert, Bennett; Bisson, Kelsey

    2015-11-01

    Studies over the past decade have reported power-law distributions for the areas of terrestrial lakes and Arctic melt ponds, as well as fractal relationships between their areas and coastlines. Here we report similar fractal structure of ponds in a tidal flat, thereby extending the spatial and temporal scales on which such phenomena have been observed in geophysical systems. Images taken during low tide of a tidal flat in Damariscotta, Maine, reveal a well-resolved power-law distribution of pond sizes over three orders of magnitude with a consistent fractal area-perimeter relationship. The data are consistent with the predictions of percolation theory for unscreened perimeters and scale-free cluster size distributions and are robust to alterations of the image processing procedure. The small spatial and temporal scales of these data suggest this easily observable system may serve as a useful model for investigating the evolution of pond geometries, while emphasizing the generality of fractal behavior in geophysical surfaces.

  3. Treatment stability in patients with Class II malocclusion treated with 2 maxillary premolar extractions or without extractions.

    Science.gov (United States)

    Janson, Guilherme; Camardella, Leonardo Tavares; Araki, Janine Della Valle; de Freitas, Marcos Roberto; Pinzan, Arnaldo

    2010-07-01

    The purpose of this study was to compare the occlusal stability of Class II malocclusion treatment with and without extraction of 2 maxillary premolars. A sample of 59 records from patients with complete Class II malocclusion was used. This sample was divided into 2 groups with the following characteristics: group 1, comprising 29 patients treated without extractions, and group 2, comprising 30 patients treated with extraction of 2 maxillary premolars. Dental cast measurements were obtained before and after treatment and at a minimum of 2.4 years after treatment. The pretreatment, posttreatment, and postretention occlusal statuses were evaluated with the peer assesment rating index. The occlusal indexes at the postretention stage and the posttreatment changes and percentages of posttreatment changes were compared with t tests. The nonextraction and the 2 maxillary premolar extraction treatment protocols of complete Class II malocclusions had no statistically significant differences in occlusal stability. Finishing Class II malocclusion treatment with the molars in a Class II relationship has similar occlusal stability as finishing with the molars in a Class I relationship. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  4. Water transparency of Macrobrachium amazonicum ponds under different feeding regimens and selective harvests

    Directory of Open Access Journals (Sweden)

    Erlei Cassiano Keppeler

    2008-12-01

    Full Text Available In aquaculture systems, water transparency is affected by water supply, feeding rate and fertilization. A study was conducted from December 19, 2003 to May 12, 2004 for a period of approximately 120 days. Twelve 0.01ha earthen ponds were used with 1m deep water. Prawns were fed commercial diet at a rate of 7 to 9% of biomass until the 14th week. Then, three groups of three ponds were fed with 3%, 5% and 7% of prawn biomass. The remaining three other ponds were subjected to combined harvest. The amount of penetrating light was calculated according to Lambert's Law, described as Iz = Ioe-kz. Evaluation of the data using Kruskall-Wallis, complemented by LSD test, showed a significant difference between treatments of 3 and 5% (p 0.05.

  5. [Effect of water depths on hydraulic performance of pond wetlands].

    Science.gov (United States)

    Guo, Chang-Qiang; Dong, Bin; Liu, Jun-Jie; Liu, Chun-Guo; Feng, Da-Peng; Liu, Fang-Ping

    2014-11-01

    Pond wetlands have been widely used in the treatment of drainage water from paddy fields. However, wetland hydraulic performance and purification effects are affected by many factors, such as water depth, flow rate, aspect ratio and vegetation distribution, and the better understanding of these factors would be helpful to improve the quality of wetland design, operation and management. This paper analyzed the effect of three different water depths (20, 40 and 60 cm) on the hydraulic performance of pond wetland through the dye tracer experiments with Rhodamine WT. The hydraulic indices, i. e., effective volume ratio, nominal serial complete mixing tanks (N), hydraulic efficiency (λ), were selected for analysis through the hydraulic residence time distribution (RTD) curve. The results showed that the effective volume rate rose from 0.421 to 0.844 and the hydraulic efficiency from 0.281 to 0.604 when the water depth declined from 60 cm to 20 cm. This indicated that the wetland hydraulic performance improved as the water depth decreased. In addition, the hydraulic performance of the first half of the wetland was significantly better than that of the second half. The flow regime of the first half approached complete mixing because of the mixing index (N) approaching 1 and its effective volume rate was above 0.9 when the water depth was relatively low (20 and 40 cm). The normalized RTD curves demonstrated a good agreement between moment analysis parameters and hydraulic parameters, and a great consistency between the hydraulic parameters and moment index which was not affected by tail truncation error. The experimental study concluded that a lower water depth was favorable to improve the hydraulic performance of pond wetlands.

  6. [Transpedicular dynamics stabilization in the treatment of lumbar stenosis. Fourth years follow-up].

    Science.gov (United States)

    Reyes-Sánchez, Alejandro; Sánchez-Bringas, Guadalupe; Zarate-Kalfopulos, Barón; Alpizar-Aguirre, Armando; Lara-Padilla, Eleazar; Rosales-Olivares, Luis Miguel

    2013-01-01

    We need to evaluate the efficacy and safety of the use of dynamic fixation in patients with narrow lumbar through comparing the assessment of two years with 4 years of follow-up. Prospective, longitudinal, autocontrol deliberately and sequential intervention, in lumbar stenosis patients who made treatment with dynamic stabilization posterior type Acuflex. An evaluation of four of final follow-up. 18 patients who completed follow-up two years results as a basis for comparison: 18 patients, 14 female and 4 male, average age 44.05 years. Pain evaluated with numerical visual scale was found in the lower back at 24 months in an average of 2.84 and 48 months in 3.26. We measured the functional level of Oswestry at two years to be 24% and at four years 22.44%, with a p = 0.373. In the magnetic resonance for classification of patients 15 Pfirrmann without changes and three with increase of a degree. According to patients 2 Modic changes one of type 0 to type III and another to type I. We have observed that five patients have required second surgery for removal of material findings. There is no change between 2 and 4 years in the scale of Oswestry and pain with visual numerical scale functionality. The average height in discs had change with statistical significance, in the comparative period. The intervertebral discs had changes in 3 patients with direct relationship between scale of Pfirrmann and Modic. The rest of patients keep rehydration and normal disc height.

  7. The Stability of CI02 as a Product of Gas Phase Decontamination Treatments

    International Nuclear Information System (INIS)

    Simmons, D. W.

    1994-01-01

    The gas phase decontamination project is investigating the use of chlorine trifluoride (ClF 3 ) to fluorinate nonvolatile uranium deposits to produce uranium hexafluoride (UF 6 ) gas. The potential existence of chlorine dioxide (ClO 2 ) during gas phase decontamination with ClF 3 has been the subject of recent safety discussions. Some of the laboratory data collected during feasibility studies of the gas phase process has been evaluated for the presence of ClO 2 in the product gas stream. The preliminary evidence to date can be summarized as follows: (1) ClO 2 was not detected in the flow loop in the absence of ClF 3 ; (2) ClO 2 was not detected in the static reactors in the absence of both ClF 3 and ClF; and (3) ClO 2 was detected in a static reactor in the absence of all fluorinating gases. The experimental evidence suggests that ClO 2 will not exist in the presence of ClF 3 , ClF, or UF 6 . The data analyzed to date is insufficient to determine the stability of ClO 2 in the presence of ClO 2 F. Thermodynamic calculations of the ClF 3 + H 2 O system support the experimental evidence, and suggest that ClO 2 will not exist in the presence of ClO 2 F. Additional experimental efforts are needed to provide a better understanding of the gas phase ClF 3 treatments and the product gases. However, preliminary evidence to date suggests that ClO 2 should not be present as a product during the normal operations of the gas phase decontamination project

  8. Oxidative stability of cnicken thigh meat after treatment of abies alba essential oil

    Directory of Open Access Journals (Sweden)

    Adriana Pavelková

    2015-12-01

    Full Text Available In the present work, the effect of the Abies alba essential oil in two different concentrations on oxidative stability of chicken thigh muscles during chilled storage was investigated. In the experiment were chickens of hybrid combination Cobb 500 after 42 days of the fattening period slaughtered.  All the broiler chickens were fed with the same feed mixtures and were kept under the same conditions. The feed mixtures were produced without any antibiotic preparations and coccidiostatics. After slaughtering was dissection obtained fresh chicken thigh with skin from left half-carcass which were divided into five groups (n = 5: C - control air-packaged group; A1 - vacuum-packaged experimental group; A2 - vacuum-packaged experimental group with ethylenediaminetetraacetic acid (EDTA solution 1.50% w/w; A3 - vacuum-packaged experimental group with Abies alba oil 0.10% v/w and A4 - vacuum-packaged experimental group with Abies alba oil 0.20% v/w. The Abies alba essential oil was applicate on ground chicken things and immediately after dipping, each sample was packaged using a vacuum packaging machine and storage in refrigerate at 4 ±0.5 °C. Thiobarbituric acid (TBA value expressed in number of malondialdehyde was measured in the process of first storage day of 1st, 4th, 8th, 12th and 16th day after slaughtering and expressed on the amount of malondialdehyde (MDA in 1 kg sample. The treatments of chicken things with Abies alba essential oil show statistically significant differences between all testing groups and control group, where higher average value of MDA measured in thigh muscle of broiler chickens was in samples of control group (0.4380 mg.kg-1 compared to experimental groups A1 (0.124 mg.kg-1, A2 (0.086 mg.kg-1, A3 (0.082 mg.kg-1 and A4 (0.077 mg.kg-1 after 16-day of chilled storage. Experiment results show that the treatment of chicken thigh with Abies alba essential oil positively influenced on the reduction of oxidative processes in thigh

  9. Oxidative stability of chicken thigh meat after treatment of fennel and savory essential oils

    Directory of Open Access Journals (Sweden)

    Adriana Pavelková

    2016-05-01

    Full Text Available In the present work, the effect of the fennel and savory essential oils on oxidative stability of chicken thigh muscles during chilled storage was investigated. In the experiment were used chickens of hybrid combination Cobb 500 after 42 days of the fattening period. The obtained fresh chicken thigh with skin from left half-carcass were divided into five groups (n = 5: C - control air-packaged group; A1 - vacuum-packaged experimental group; A2 - vacuum-packaged experimental group with EDTA solution 1.50% w/w; A3 - vacuum-packaged experimental group with fennel (Foeniculum vulgare essential oil at concentrations 0.2% v/w and A4 - vacuum-packaged experimental group with savory (Satureja hortensis essential oil at concentration 0.2% v/w. The essential oils were applicate on surface chicken thighs. The chicken thighs were packaged using a vacuum packaging machine and stored in refrigerate at                 4 ±0.5 °C. The value of thiobarbituric acid (TBA expressed as amount of malondialdehyde (MDA in 1 kg sample was measured during storage in 1st, 4th, 8th, 12th and 16th day. The treatments of chicken thighs with fennel and savory essential oils show statistically significant differences between all testing groups and control group, where higher average value of MDA measured in thigh muscle of broiler chickens was in samples of control group                 (0.359 mg.kg-1 compared to experimental groups A1 (0.129 mg.kg-1, A2 (0.091 mg.kg-1, A3 (0.084 mg.kg-1 and A4 (0.089 mg.kg-1 after 16-day of chilled storage. Experiment results show that the treatment of chicken thigh with fennel and savory essential oils had positive influence on the reduction of oxidative processes in thigh muscles during chilling storage and use of essential oil is one of the options increase shelf life of fresh chicken meat.

  10. Understanding the biological activity of high rate algae ponds through the calculation of oxygen balances.

    Science.gov (United States)

    Arbib, Zouhayr; de Godos Crespo, Ignacio; Corona, Enrique Lara; Rogalla, Frank

    2017-06-01

    Microalgae culture in high rate algae ponds (HRAP) is an environmentally friendly technology for wastewater treatment. However, for the implementation of these systems, a better understanding of the oxygenation potential and the influence of climate conditions is required. In this work, the rates of oxygen production, consumption, and exchange with the atmosphere were calculated under varying conditions of solar irradiance and dilution rate during six months of operation in a real scale unit. This analysis allowed determining the biological response of these dynamic systems. The rates of oxygen consumption measured were considerably higher than the values calculated based on the organic loading rate. The response to light intensity in terms of oxygen production in the bioreactor was described with one of the models proposed for microalgae culture in dense concentrations. This model is based on the availability of light inside the culture and the specific response of microalgae to this parameter. The specific response to solar radiation intensity showed a reasonable stability in spite of the fluctuations due to meteorological conditions. The methodology developed is a useful tool for optimization and prediction of the performance of these systems.

  11. Evaluation of carbon monoxide treatment in modified atmosphere packaging or vacuum packaging to increase color stability of fresh beef.

    Science.gov (United States)

    Jayasingh, P; Cornforth, D P; Carpenter, C E; Whittier, D

    2001-11-01

    Our goal was to obtain > 21 days red color stability for carbon monoxide (CO)-treated beef steaks in vacuum packaging (VP). In preliminary tests, pretreatment for 24 h in a 5% CO modified atmosphere package (MAP) was needed to maintain redness after re-packaging in VP. Pressure pretreatment with 5% CO for 2 h developed redness, but was impractical for large-scale application. Color stability and microbial load were then compared after treatment of steaks in 5% CO-MAP for 24 h, then VP; 100% CO-MAP for 1 h, then VP; steaks and ground beef in 0.5% CO-MAP; and steaks and ground beef in polyvinyl chloride (PVC) wrap. Steaks remained red for 5, 6, 8 and 10(6)cfu/cm(2)) at 5, 6, 7 and <2-weeks, respectively. Thus, extended color stability in VP was achieved by pretreatment with 5% CO for 24 h or 100% CO for 1 h.

  12. Validation Hydrodynamic Models of Three Topological Models of Secondary Facultative Ponds

    Directory of Open Access Journals (Sweden)

    Aponte-Reyes Alxander

    2014-10-01

    Full Text Available A methodology was developed to analyze boundary conditions, the size of the mesh and the turbulence of a mathematical model of CFD, which could explain hydrodynamic behavior on facultative stabilization ponds, FSP, built to pilot scale: conventional pond, CP, baffled pond, BP, and baffled-mesh pond, BMP. Models dispersion studies were performed in field for validation, taking samples into and out of the FSP, the information was used to carry out CFD model simulations of the three topologies. Evaluated mesh sizes ranged from 500,000 to 2,000,000 elements. The boundary condition in Pared surface-free slip showed good qualitative behavior and the turbulence model κ–ε Low Reynolds yielded good results. The biomass contained in LFS generates interference on dispersion studies and should be taken into account in assessing the CFD modeling, the tracer injection times, its concentration at the entrance, the effect of wind on CFD, and the flow models adopted as a basis for modeling are parameters to be taken into account for the CFD model validation and calibration.

  13. Developing Ecological Models on Carbon and Nitrogen in Secondary Facultative Ponds

    Directory of Open Access Journals (Sweden)

    Aponte-Reyes Alexander

    2014-07-01

    Full Text Available Ecological models formulated for TOC, CO2, NH4+, NO3- and NTK, based in literature reviewed and field work were obtained monitoring three facultative secondary stabilization ponds, FSSP, pilots: conventional pond, CP, baffled pond, BP, and baffled-meshed pond, BMP. Models were sensitive to flow inlet, solar radiation, pH and oxygen content; the sensitive parameters in Carbon Model were KCOT Ba, umax Ba, umax Al, K1OX, VAl, R1DCH4, YBh. The sensitive parameters in the Nitrogen model were KCOT Ba, umax Ba, umax Al, VAl, KOPH, KOPA, r4An. The test t–paired showed a good simulating of Carbon model refers to TOC in FSSP; on the other side, the Nitrogen model showed a good simulating of NH4+. Different topological models modify ecosystem ecology forcing different transformation pathways of Nitrogen; equal transformations of the Carbon BMP topology could be achieved using lower volumes, however, a calibration for a new model would be required. Carbon and Nitrogen models developed could be coupled to hydrodynamics models for better modeling of FSSP.

  14. Determination of Summertime VOC Emission Rates from Produced Water Ponds in the Uintah Basin

    Science.gov (United States)

    Martin, R. S.; Woods, C.; Lyman, S.

    2013-12-01

    The observance of excess ozone concentrations in Utah's Uintah Basin over past several years has prompted several investigations into the extent and causes of the elevated ozone. Among these is the assessment of potential emissions of reactive VOCs. Evaporation ponds, used a remediation technique for treatment of contaminated production and other waters, are one potential source of significant VOC emissions and is estimated that there are around 160 such ponds within the Uintah Basin's oil and gas production areas. In June 2012 VOC emission rates for several reactive VOCs were derived for an evaporation facility consisting of a small inlet pond (≈0.03 acres) and two larger, serial ponds (≈4.3 acres each). The emission rates were determined over three sampling periods using an inverse modeling approach. Under this methodology, ambient VOC concentrations are determined at several downwind locations through whole-air collection into SUMMA canisters, followed by GC/MS quantification and compared with predicted concentrations using an EPA-approved dispersion model, AERMOD. The presumed emission rates used within the model were then adjusted until the modeled concentrations approach the observed concentrations. The derived emission rates for the individual VOCs were on the order of 10-3 g/s/m2 from the inlet pond and 10-6 g/s/m2 from the larger ponds. The emissions from the 1st pond in series after the inlet pond were about 3-4x the emissions from the 2nd pond. These combined emission rates are about an order of magnitude those reported for a single study in Colorado (Thoma, 2009). It should be noted, however, that the variability about each of the VOC emission rates was significant (often ×100% at the 95% confidence interval). Extrapolating these emission rates to the estimated total areas of all the evaporation ponds within Basin resulted in calculated Basin-wide VOC emissions 292,835 tons/yr. However, Bar-Ilan et al. (2009) estimated 2012 VOC oil and gas related

  15. Stabilizing group treatment for Complex Posttraumatic Stress Disorder related to childhood abuse based on psycho-education and cognitive behavioral therapy: A pilot study

    NARCIS (Netherlands)

    Dorrepaal, E.; Thomaes, K.; Smit, J.H.; van Balkom, A.J.L.M.; van Dyck, R.; Veltman, D.J.; Draijer, P.J.

    2010-01-01

    Objective: This study tests a Stabilizing Group Treatment protocol, designed for the management of the long-term sequelae of child abuse, that is, Complex Posttraumatic Stress Disorder (Complex PTSD). Evidence-based treatment for this subgroup of PTSD patients is largely lacking. This stabilizing

  16. LOW COST SOLIDIFICATION/STABILIZATION TREATMENT FOR SOILS CONTAMINATED WITH DIOXIN, PCP AND CREOSOTE

    Science.gov (United States)

    The USEPA's NRMRL conducted successful treatability tests of innovative solidification/stabilization (S/S) formulations to treat soils contaminated with dioxins, pentachlorophenol (PCP), and creosote from four wood preserving sites. Formulations developed during these studies wer...

  17. Stability of direct oral anticoagulants in whole blood and plasma from patients in steady state treatment

    DEFF Research Database (Denmark)

    McGrail, Rie; Revsholm, Jesper; Nissen, Peter H

    2016-01-01

    Using functional haemostasis assays, we demonstrated important differences in stability of direct oral anticoagulants (DOACs) in citrated whole blood and plasma from DOAC treated patients. Laboratories and clinicians should take this into consideration and adjust clinical practices accordingly....

  18. Microbial activities and communities in oil sands tailings ponds

    Energy Technology Data Exchange (ETDEWEB)

    Gieg, Lisa; Ramos, Esther; Clothier, Lindsay; Bordenave, Sylvain; Lin, Shiping; Voordouw, Gerrit; Dong, Xiaoli; Sensen, Christoph [University of Calgary (Canada)

    2011-07-01

    This paper discusses how the microbial communities and their activity play a vital role in tailings ponds. The ponds contain microorganisms along with metals, hydrocarbon diluent, naphthenic acid and others. The ponds play an important role in mining operations because they store bitumen extraction waste and also allow water to be re-used in the bitumen extraction process. Pond management presents a few challenges that include, among others, gas emissions and the presence of toxic and corrosive acids. Microbial activities and communities help in managing these ponds. Microbial activity measurement in active and inactive ponds is described and analyzed and the results are presented. The conditions for reducing sulfate, nitrate and iron are also presented. From the results it can be concluded that naphthenic acids can potentially serve as substrates for anaerobic populations in tailings ponds.

  19. Performance of pond-wetland complexes as a preliminary processor of drinking water sources.

    Science.gov (United States)

    Wang, Weidong; Zheng, Jun; Wang, Zhongqiong; Zhang, Rongbin; Chen, Qinghua; Yu, Xinfeng; Yin, Chengqing

    2016-01-01

    Shijiuyang Constructed Wetland (110 hm(2)) is a drinking water source treatment wetland with primary structural units of ponds and plant-bed/ditch systems. The wetland can process about 250,000 tonnes of source water in the Xincheng River every day and supplies raw water for Shijiuyang Drinking Water Plant. Daily data for 28 months indicated that the major water quality indexes of source water had been improved by one grade. The percentage increase for dissolved oxygen and the removal rates of ammonia nitrogen, iron and manganese were 73.63%, 38.86%, 35.64%, and 22.14% respectively. The treatment performance weight of ponds and plant-bed/ditch systems was roughly equal but they treated different pollutants preferentially. Most water quality indexes had better treatment efficacy with increasing temperature and inlet concentrations. These results revealed that the pond-wetland complexes exhibited strong buffering capacity for source water quality improvement. The treatment cost of Shijiuyang Drinking Water Plant was reduced by about 30.3%. Regional rainfall significantly determined the external river water levels and adversely deteriorated the inlet water quality, thus suggesting that the "hidden" diffuse pollution in the multitudinous stream branches as well as their catchments should be the controlling emphases for river source water protection in the future. The combination of pond and plant-bed/ditch systems provides a successful paradigm for drinking water source pretreatment. Three other drinking water source treatment wetlands with ponds and plant-bed/ditch systems are in operation or construction in the stream networks of the Yangtze River Delta and more people will be benefited. Copyright © 2015. Published by Elsevier B.V.

  20. Stability of chitosan nanoparticles for L-ascorbic acid during heat treatment in aqueous solution.

    Science.gov (United States)

    Jang, Keum-Il; Lee, Hyeon Gyu

    2008-03-26

    This study investigated the stability and characteristics of L-ascorbic acid (AA)-loaded chitosan (CS) nanoparticles during heat processing in aqueous solutions. AA-loaded CS nanoparticles were prepared by ionic gelation of CS with tripolyphosphate (TPP) anions. The smallest CS nanoparticles (170 nm) were obtained with a CS concentration of 1.5 mg/mL and a TPP concentration of 0.6 mg/mL. As the concentration of AA increased from 0.1 to 0.3 mg/mL, the particle size increased, while the zeta potential decreased, and the encapsulation efficiency of AA remained within a fixed range (10-12%). During heat processing at various temperatures, the size and zeta potential of the particles decreased rapidly in the first 5 min and then slowly fell to the regular range. At the beginning of the release profiles, the burst release-related stability of the surface increased with the temperature. Then, the release of the internal AA was constantly higher with a longer release time. Consequently, it was confirmed that the stability of AA-loaded CS nanoparticles was affected by temperature but that the internal stability was greater than the surface stability. These results demonstrate the stability of CS nanoparticles for AA during heat processing and suggest the possible use of AA-loaded CS nanoparticles to enhance antioxidant effects because of the continuous release of AA from CS nanoparticles in food processing.

  1. The use of resorbable plates in association with dental arch stabilization in the treatment of mandibular fractures in children.

    Science.gov (United States)

    Li, Zhi; David, Ongodia; Li, Zu-Bing

    2014-07-01

    The purpose of this study was to investigate the effect of resorbable plate fixation in association with dental arch stabilization in the treatment of displaced mandibular fractures in children. Thirteen children (5 girls and 8 boys, age range 2 years 5 months to 12 years 2 months) with displaced mandibular fractures were included in this case series. Open reduction by intraoral approach was performed on these patients, and the fractures were fixed using resorbable plates and monocortical screws placed at the lower border of the mandible. At the same time, an arch bar or orthodontic wire splint was anchored using stainless steel wires or resin on the teeth to stabilize the whole mandibular dental arch. Postoperatively, follow-up was undertaken to evaluate the fracture healing, mandible movement, and mandible growth. Postoperatively, all patients achieved uneventful healing; premorbid occlusion restoration and wound healing were achieved, along with unimpaired function and normal growth and development of the mandible. Complications such as damage to tooth buds, infection, malunion, and nonunion were not encountered in these patients. Resorbable plates use in association with dental arch stabilization can provide good stabilization for mandibular fractures and is a promising approach for the treatment of displaced mandibular fractures in children. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  2. Effect of heat-treatment with raw cotton seed oil on decay resistance and dimensional stability of Beech (Fagus orientalis

    Directory of Open Access Journals (Sweden)

    مریم قربانی

    2015-05-01

    Full Text Available This research was conducted to determine the effect of heat-treatment with raw cotton seed oil on decay resistance and dimensional stability of beech according to EN113 and ASTM-D1037 standards respectively. The heat treatment with raw cotton seed oil was carried out in the cylinder at the temperatures of 130 and 170oC for 30 and 60 minutes. Oil uptake, density, volumetric swelling, water absorption and weight loss exposed to decay were measured. Oil uptake at 30 and 60 min were determined 10.5 and 13.3 Kg/cm3 respectively. Oil-heat treated samples at 30min and 130°C indicated the maximum density with 87.7% increase. According to results, oil-heat treatment improved water repellency and dimensional stability. Water absorption in 130°C and 60 minutes decreased 76% in comparison with control. Decay resistance of oil soaked samples for 60minutes was 80.2% more than control samples. Oil-heat treatment compared with oil treatment improved decay resistance, this effect was significant at 30 min. The temperature rise of oil–heat treatment at 30 minutes improved decay resistance, but the improvement under same level of temperature with increase time was not significant.

  3. Evaluating the Stability of Open Bite Treatments and Its Predictive Factors in the Retention Phase during Permanent Dentition.

    Science.gov (United States)

    Salehi, Parisa; Pakshir, Hamid Reza; Hoseini, Seyed Ali Reza

    2015-03-01

    Orthodontists often find challenges in treating the anterior open bite and maintaining the results. This retrospective study was aimed to evaluate the stability of corrected open bite in the retention phase during permanent dentition. A total number of 37 patients, including 20 males and 17 females, with the mean age of 18±2.1 years at the beginning of the treatment were studied after correction of the anterior open bite. Overbites of the patients were measured from their lateral cephalograms before (T1), at the end (T2) and at least 3 years after the end of the treatment in the presence of their fixed retainers (T3).The mean overbite changes and the number of patients with open bite, due to treatment relapse, at T3 were calculated. The relationship between the pre-treatment factors and the treatment relapse was assessed at T1 and T2. Also the effects of treatment methods, extraction and adjunctive use of removable appliances on the post-treatment relapse were evaluated. The mean overbite change during the post-treatment period was -0.46±0.7 mm and six patients (16.2%) had relapse in the follow-up recall. Cephalometric Jaraback index showed statistically significant, but weak correlation with overbite changes after the treatment (p= 0.035; r= -0.353). No significant difference was found between the extraction and non-extraction groups (p= 0.117) the use and the type of the removable appliances (p= 0.801). Fixed retainers alone are insufficient for stabilizing the results of corrected open bite. The change of overbite in the retention phase could not be predicted from cephalometric measurements. Extraction and use of adjunctive removable appliance did not have any effect on the treatment relapse.

  4. Evaluating the Stability of Open Bite Treatments and Its Predictive Factors in the Retention Phase during Permanent Dentition

    Science.gov (United States)

    Salehi, Parisa; Pakshir, Hamid Reza; Hoseini, Seyed Ali Reza

    2015-01-01

    Statement of the Problem Orthodontists often find challenges in treating the anterior open bite and maintaining the results. Purpose This retrospective study was aimed to evaluate the stability of corrected open bite in the retention phase during permanent dentition. Materials and Method A total number of 37 patients, including 20 males and 17 females, with the mean age of 18±2.1 years at the beginning of the treatment were studied after correction of the anterior open bite. Overbites of the patients were measured from their lateral cephalograms before (T1), at the end (T2) and at least 3 years after the end of the treatment in the presence of their fixed retainers (T3).The mean overbite changes and the number of patients with open bite, due to treatment relapse, at T3 were calculated. The relationship between the pre-treatment factors and the treatment relapse was assessed at T1 and T2. Also the effects of treatment methods, extraction and adjunctive use of removable appliances on the post-treatment relapse were evaluated. Results The mean overbite change during the post-treatment period was -0.46±0.7 mm and six patients (16.2%) had relapse in the follow-up recall. Cephalometric Jaraback index showed statistically significant, but weak correlation with overbite changes after the treatment (p= 0.035; r= -0.353). No significant difference was found between the extraction and non-extraction groups (p= 0.117) the use and the type of the removable appliances (p= 0.801). Conclusion Fixed retainers alone are insufficient for stabilizing the results of corrected open bite. The change of overbite in the retention phase could not be predicted from cephalometric measurements. Extraction and use of adjunctive removable appliance did not have any effect on the treatment relapse. PMID:25759854

  5. Influence of mechanical and thermal treatments on microstructure and mechanical properties of titanium stabilized austenitic stainless steels

    International Nuclear Information System (INIS)

    Sidhom, H.

    1983-12-01

    Thermal and mechanical treatments for microstructure optimization in titanium stabilized austenitic stainless steels used in nuclear industry are examined. The steels studied Z10CNDT15-15B and Z6CNDT17-13 are of the type 15-15 Ti and 316 Ti. These treatments allow the elimination of casting heterogeneity produced by dendritic solidification, improve mechanical properties particularly creep and the best compromise between grain size solid solution of metal additions is obtained. Secondary precipitation of (TiMo)C on dislocations is improved by a previous strain hardening. The precipitation reinforce the good effect of strain hardening by stabilization of the microstructure producing a better resistance to recrystallization [fr

  6. Intraspecific competition increases toxicant effects in outdoor pond microcosms.

    Science.gov (United States)

    Knillmann, Saskia; Stampfli, Nathalie C; Beketov, Mikhail A; Liess, Matthias

    2012-10-01

    Competition is a ubiquitous factor in natural populations and has been reported to alter the ecological impact of xenobiotics. We investigated conditions that mirror the natural variation of environmental factors. For this, different treatments were applied to 96 outdoor pond microcosms by shading the ponds and harvesting the communities. Then, the effect of esfenvalerate (0.03, 0.3, and 3 μg/L) on populations of Daphnia spp. was investigated. The pesticide effect and the sensitivity of Daphnia spp. in the context of a zooplankton community was increased by intraspecific competition 11 days after contamination. This relationship was most pronounced at 0.03 and 0.3 μg/L esfenvalerate, which were the concentrations that led to partial mortality. In contrast, interspecific interaction did not significantly alter the effect of the toxicant on Daphnia spp. Modelled concentration-response curves showed that the negative effects of the pesticide differed by a factor of up to 100 depending on the strength of intraspecific competition. In addition, a wider range of concentrations led to negative effects at high levels of intraspecific competition than at low levels. We argue that increased intraspecific competition reduces the availability of resources at the individual level and thereby increases the effect of contaminants. This knowledge about the interaction between competition and the response to toxicants is important in assessing the effects of these factors under field conditions.

  7. Enhancing nitrification at low temperature with zeolite in a mining operations retention pond

    Directory of Open Access Journals (Sweden)

    Misha eMiazga-Rodriguez

    2012-07-01

    Full Text Available Ammonium nitrate explosives are used in mining operations at Diavik Diamond Mines Inc. in the Northwest Territories, Canada. Residual nitrogen is washed into the mine pit and piped to a nearby retention pond where its removal is accomplished by microbial activity prior to a final water treatment step and release into the sub-Arctic lake, Lac de Gras. Microbial removal of ammonium in the retention pond is rapid during the brief ice-free summer, but often slows under ice cover that persists up to nine months of the year. The aluminosilicate mineral zeolite was tested as an additive to retention pond water to increase rates of ammonium removal at 4 °C. Water samples were collected across the length of the retention pond monthly over a year. The structure of the microbial community (bacteria, archaea, and eukarya, as determined by denaturing gradient gel electrophoresis of PCR-amplified small subunit ribosomal RNA genes, was more stable during cold months than during July-September, when there was a marked phytoplankton bloom. Of the ammonia-oxidizing community, only bacterial amoA genes were consistently detected. Zeolite (10 g was added to retention pond water (100 mL amended with 5 mM ammonium and incubated at 12 °C to encourage development of a nitrifying biofilm. The biofilm community was composed of different amoA phylotypes from those identified in gene clone libraries of native water samples. Zeolite biofilm was added to fresh water samples collected at different times of the year, resulting in a significant increase in laboratory measurements of potential nitrification activity at 4 °C. A significant positive correlation between the amount of zeolite biofilm and potential nitrification activity was observed; rates were unaffected in incubations containing 1-20 mM ammonium. Addition of zeolite to retention ponds in cold environments could effectively increase nitrification rates year round by concentrating active nitrifying biomass.

  8. Post orthodontic treatment stability measurement in dentoskeletal class I malocclusion based on the objective grading system index

    Directory of Open Access Journals (Sweden)

    Bernard Anthony Pasaribu

    2011-03-01

    Full Text Available The purpose of this study was to examine the stability of orthodontic treatment results in dentoskeletal class I malocclusion treated with and without extraction of four premolars and to compare the stability of treatment result between those groups. Occlusal relationship after treatment and six-month post retention were measured on dental cast using The Objective Grading System Index at Orthodontic Specialist Clinic, Faculty of Dentistry Universitas Padjadjaran. The analytic descriptive study was carried out on 30 samples that comprised 14 samples were treated without extraction of four premolars and 16 samples were treated with extraction of four premolars. ABO Measuring Gauge was used to measure seven variables: tooth alignment, the height of the marginal ridges, buccolingual inclination, occlusal relationships, occlusal contacts, overjet, and interproximal tooth contacts. The results were statistically analyzed with the Wilcoxon rank test to test the difference of The Objective Grading System Index between posttreatment and postretension. Mann-Whitney U test was applied to determine the difference between the group with the extraction of four premolars and the group without extraction of four premolars. The level of significance was set at 0.05. The results of this study showed these following variables: tooth alignment, occlusal contacts, and overjet were unstable at the group with the extraction of four premolars, while only tooth alignment was found to be unstable in the group without extraction of the four premolars. Mann-Whitney U test did not show statistically significant difference in stability comparison test between the groups.

  9. Invertebrates in stormwater wet detention ponds — Sediment accumulation and bioaccumulation of heavy metals have no effect on biodiversity and community structure

    International Nuclear Information System (INIS)

    Stephansen, Diana Agnete; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Pedersen, Morten Lauge; Vollertsen, Jes

    2016-01-01

    The invertebrate diversity in nine stormwater wet detention ponds (SWDP) was compared with the diversity in eleven small shallow lakes in the western part of Denmark. The SWDPs and lakes were chosen to reflect as large a gradient of pollutant loads and urbanization as possible. The invertebrates as well as the bottom sediments of the ponds and shallow lakes were analyzed for copper, iron, zinc, cadmium, chromium, lead, aluminum, nickel, arsenic and the potentially limiting nutrient, phosphorus. The Principal Component Analysis showed that invertebrates in SWDPs and lakes differed with respect to bioaccumulation of these elements, as did the sediments, albeit to a lesser degree. However, the Detrended Correspondence Analysis and the TWINSPAN showed that the invertebrate populations of the ponds and lakes could not be distinguished, with the possible exception of highway ponds presenting a distinct sub-group of wet detention ponds. The SWDPs and shallow lakes studied seemed to constitute aquatic ecosystems of similar taxon richness and composition as did the 11 small and shallow lakes. This indicates that SWDPs, originally constructed for treatment and flood protection purposes, become aquatic environments which play a local role for biodiversity similar to that of natural small and shallow lakes. - Highlights: • Biota of stormwater ponds had higher levels of metals compared to natural lakes. • Bioaccumulation of metals did not affect the biodiversity of the water bodies. • Biota composition in stormwater ponds and natural lakes was indistinguishable. • Stormwater ponds can play a role for biodiversity similar to natural lakes.

  10. Invertebrates in stormwater wet detention ponds — Sediment accumulation and bioaccumulation of heavy metals have no effect on biodiversity and community structure

    Energy Technology Data Exchange (ETDEWEB)

    Stephansen, Diana Agnete, E-mail: das@civil.aau.dk [Department of Civil Engineering, Aalborg University, Thomas Manns Vej 23, 9220 Aalborg East (Denmark); Nielsen, Asbjørn Haaning [Department of Civil Engineering, Aalborg University, Thomas Manns Vej 23, 9220 Aalborg East (Denmark); Hvitved-Jacobsen, Thorkild [Department of Environmental Engineering, Aalborg University, Fredrik Bajers Vej 7H, 9200 Aalborg East (Denmark); Pedersen, Morten Lauge; Vollertsen, Jes [Department of Civil Engineering, Aalborg University, Thomas Manns Vej 23, 9220 Aalborg East (Denmark)

    2016-10-01

    The invertebrate diversity in nine stormwater wet detention ponds (SWDP) was compared with the diversity in eleven small shallow lakes in the western part of Denmark. The SWDPs and lakes were chosen to reflect as large a gradient of pollutant loads and urbanization as possible. The invertebrates as well as the bottom sediments of the ponds and shallow lakes were analyzed for copper, iron, zinc, cadmium, chromium, lead, aluminum, nickel, arsenic and the potentially limiting nutrient, phosphorus. The Principal Component Analysis showed that invertebrates in SWDPs and lakes differed with respect to bioaccumulation of these elements, as did the sediments, albeit to a lesser degree. However, the Detrended Correspondence Analysis and the TWINSPAN showed that the invertebrate populations of the ponds and lakes could not be distinguished, with the possible exception of highway ponds presenting a distinct sub-group of wet detention ponds. The SWDPs and shallow lakes studied seemed to constitute aquatic ecosystems of similar taxon richness and composition as did the 11 small and shallow lakes. This indicates that SWDPs, originally constructed for treatment and flood protection purposes, become aquatic environments which play a local role for biodiversity similar to that of natural small and shallow lakes. - Highlights: • Biota of stormwater ponds had higher levels of metals compared to natural lakes. • Bioaccumulation of metals did not affect the biodiversity of the water bodies. • Biota composition in stormwater ponds and natural lakes was indistinguishable. • Stormwater ponds can play a role for biodiversity similar to natural lakes.

  11. Orthodontic evolution: an update for the general dental practitioner. Part 2: psychosocial aspects of orthodontic treatment, stability of treatment, and the TMJ-orthodontic relationship.

    Science.gov (United States)

    McGuinness, Niall J P

    2008-01-01

    As a result of recent innovations and improvements, orthodontic treatment has become easier and more efficient to carry out, allowing greater numbers of patients to receive treatment. The main result of orthodontic treatment is improved dental alignment and aesthetics. Treatment has no effect on caries or periodontal disease, and the dental health gain is modest, apart from a very small percentage of destructive malocclusions. Psychological improvements using different psychological parameters show differing results and it is not clear that any psychological gains are long lasting. Social gain (greater willingness to smile, feeling good about oneself, satisfaction with dental appearance, etc.), and reported improved quality of life (QoL measures), are now becoming more important as consumer-related outcomes and may, ultimately, contribute to psychosocial and psychological status. Stability of orthodontic treatment results cannot be guaranteed and all patients need to be informed of this, and of the need for long-term retention. Malocclusion has little or no relationship to temporo-mandibular joint dysfunction and orthodontic treatment neither causes nor cures such problems. Extractions as part of orthodontic treatment do not cause TMD, nor do they cause collapse of the vertical dimension. The major improvements in dental health in the last 40 years have been accompanied by a great increase in demand for treatment. In any public health service that is free at the point of use, demand for treatment invariably exceeds the ability of resources to supply this. Indices of treatment need are widely used to determine treatment need and eligibility for treatment in public health systems. Demand for orthodontic treatment among adolescents can be as high as 60% in the general population, while the professionally-assessed need for treatment is approximately half this figure. Age, sex, socio-economic status, perceived unattractiveness of dental appearance, and availability of

  12. Stability of maxillary anterior crowding treatment Estabilidade do tratamento de apinhamento anterossuperior

    Directory of Open Access Journals (Sweden)

    Camila Leite Quaglio

    2012-08-01

    Full Text Available OBJECTIVE: To evaluate the stability and the relapse of maxillary anterior crowding treatment on cases with premolar extraction and evaluate the tendency of the teeth to return to their pretreatment position. METHODS: The experimental sample consisted of 70 patients of both sex with an initial Class I and Class II maloclusion and treated with first premolar extractions. The initial mean age was 13,08 years. Dental casts' measurements were obtained at three stages (pretreatment, posttreatment and posttreatment of 9 years on average and the variables assessed were Little Irregularity Index, maxillary arch length and intercanine. Pearson correlation coefficient was used to know if some studied variable would have influence on the crowding in the three stages (LII1, LII2, LII3 and in each linear displacement of the Little irregularity index (A, B, C, D, E in the initial and post-retention phases. RESULTS: The maxillary crowding relapse ( LII3-2 is influenced by the initial ( LII1, and the teeth tend to return to their pretreatment position. CONCLUSION: The results underline the attention that the orthodontist should be given to the maxillary anterior relapse, primarily on those teeth that are crowded before the treatment.OBJETIVO: avaliar a estabilidade e recidiva do tratamento de apinhamento dos dentes anterossuperiores em casos com extrações de pré-molares e avaliar a tendência dos dentes apinhados, no início do tratamento, a retornar à sua posição original. MÉTODOS: a amostra consistiu de 70 pacientes de ambos os sexos, com má oclusão inicial de Classe I e Classe II de Angle, tratados com extrações dos primeiros pré-molares. A idade média inicial foi de 13,08 anos. Foram avaliados os modelos de estudo nas fases inicial (T1, final (T2 e, em média, 9 anos pós-tratamento (T3 de cada paciente. As variáveis da arcada superior avaliadas e comparadas estatisticamente pela Análise de Variância (ANOVA foram: índice de irregularidade

  13. Fate of Pyrethroids in Farmland Ponds

    DEFF Research Database (Denmark)

    Mogensen, B. B.; Sørensen, P. B.; Stuer-Lauridsen, F.

    Pyrethroids constitute a group of widely used insecticides, which are toxic to aquatic organisms. This report presents the results from a 2-year study of the fate of pyrethroids in ponds, i.e. their distribution in the water column, the sediment and the surface microlayer respectively....... The measurements are used to validate a distribution model and the model analysis is used for interpretation of the results. The model analysis demonstrates that pyrethroids are adsorbed in the upper few mm of the sediment...

  14. Holocene closure of Lib Pond, Marshall Islands.

    Science.gov (United States)

    Myhrvold, Conor L; Janny, Fran; Nelson, Daniel; Ladd, S Nemiah; Atwood, Alyssa; Sachs, Julian P

    2014-01-01

    Well-preserved sediment from closed water bodies of atolls such as Lib Pond are rare opportunities to reconstruct the past regional climate, which pieced together across a latitude and longitude range identify the range of movement patterns of wider scale climate phenomena such as the Intertropical Convergence Zone (ITCZ) and El Niño Southern Oscillation (ENSO). We conducted the first physico-chemical survey of Lib Pond, a shallow, closed-water saline lake located on remote and difficult to access Lib Island in the Marshall Islands at 8° 18' 48.99″ N, 167 22' 51.90″ E in the Pacific Ocean, in July 2009. We performed a bathymetric survey, recorded salinity, dissolved oxygen, pH, and temperature profiles, monitored the tidal variability, and conducted a vegetation survey surrounding the lake. From bathymetric data we calculated the lake volume, which we used to estimate the lake's salt budget, and ultimately the residence time of water in the lake basin. We took a series of sediment cores from the lake, cores which indicate Lib Island's changing environment and climate. Radiocarbon measurements determined sediment age, and reveal significant mixing over the last 2 ka of deposition. We conclude that prior to 3 ka, Lib Island was an atoll with a central lagoon connected to the open ocean, which was then closed off from the open ocean to form the brackish system that exists today. We predict that the sediment accumulation in Lib Pond evident today will continue. As seawater is inhibited from exchanging with fresh water, Lib Pond will become a shallower lake with increasingly fresh water.

  15. Holocene closure of Lib Pond, Marshall Islands.

    Directory of Open Access Journals (Sweden)

    Conor L Myhrvold

    Full Text Available Well-preserved sediment from closed water bodies of atolls such as Lib Pond are rare opportunities to reconstruct the past regional climate, which pieced together across a latitude and longitude range identify the range of movement patterns of wider scale climate phenomena such as the Intertropical Convergence Zone (ITCZ and El Niño Southern Oscillation (ENSO. We conducted the first physico-chemical survey of Lib Pond, a shallow, closed-water saline lake located on remote and difficult to access Lib Island in the Marshall Islands at 8° 18' 48.99″ N, 167 22' 51.90″ E in the Pacific Ocean, in July 2009. We performed a bathymetric survey, recorded salinity, dissolved oxygen, pH, and temperature profiles, monitored the tidal variability, and conducted a vegetation survey surrounding the lake. From bathymetric data we calculated the lake volume, which we used to estimate the lake's salt budget, and ultimately the residence time of water in the lake basin. We took a series of sediment cores from the lake, cores which indicate Lib Island's changing environment and climate. Radiocarbon measurements determined sediment age, and reveal significant mixing over the last 2 ka of deposition. We conclude that prior to 3 ka, Lib Island was an atoll with a central lagoon connected to the open ocean, which was then closed off from the open ocean to form the brackish system that exists today. We predict that the sediment accumulation in Lib Pond evident today will continue. As seawater is inhibited from exchanging with fresh water, Lib Pond will become a shallower lake with increasingly fresh water.

  16. Cibola High Levee Pond annual report 2004

    Science.gov (United States)

    Mueller, Gordon A.; Carpenter, Jeanette; Marsh, Paul C.

    2005-01-01

    This represents the fourth and last annual report of a five year study investigating the early life ecology of the bonytail and razorback sucker at Cibola High Levee Pond. The work in 2004 included: telemetry studies, collection of physical water quality measurements, zooplankton samples, netting fish, the collection of scale samples for aging, predator/prey tank tests and a preliminary analysis of the data base.

  17. Par Pond refill water quality sampling

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J.W. II; Martin, F.D.; Westbury, H.M.

    1996-08-01

    This study was designed to document anoxia and its cause in the event that the anoxia caused a fish kill. However, no fish kill was observed during this study, and dissolved oxygen and nutrient concentrations generally remained within the range expected for southeastern reservoirs. Par Pond water quality monitoring will continue during the second summer after refill as the aquatic macrophytes become reestablished and nutrients in the sediments are released to the water column.

  18. Engineered design of SSC cooling ponds

    International Nuclear Information System (INIS)

    Bear, J.B.

    1993-05-01

    The cooling requirements of the SSC are significant and adequate cooling water systems to meet these requirements are critical to the project's successful operation. The use of adequately designed cooling ponds will provide reliable cooling for operation while also meeting environmental goals of the project to maintain streamflow and flood peaks to preconstruction levels as well as other streamflow and water quality requirements of the Texas Water Commission and the Environmental Protection Agency

  19. Beaver ponds increase methylmercury concentrations in Canadian shield streams along vegetation and pond-age gradients.

    Science.gov (United States)

    Roy, Virginie; Amyot, Marc; Carignan, Richard

    2009-08-01

    Beaver impoundments flood forested areas and may be important production sites for methylmercury (MeHg) because of the resulting enhanced microbial activity and oxygen depletion. The influence of 17 beaver impoundments on streamwater chemistry (total mercury (THg), MeHg, nutrients, cations, and anions)] was investigated by sampling sites located along vegetation and pond-age gradients in southwestern Quebec (Canada). Recently inundated beaver ponds (beaver ponds as suggested by depletions of dissolved oxygen, sulfate and nitrite-nitrate concentrations, and increases in nutrients (e.g., dissolved organic carbon, total phosphorus, and total nitrogen) in outlets compared to inlets. Acidic waters at coniferous sites may have stimulated more MeHg production than in mixed woodland regions. Lower methylation efficiencies in older ponds (> 20 years old) may be due to the degradation of less labile organic matter as ponds age. Beavers actively alter watersheds by building impoundments, and our findings indicate that this landscape disturbance may be a significant source of MeHg to downstream water bodies.

  20. Preformulation stability of Spantide II, a promising topical anti-inflammatory agent for the treatment of psoriasis and contact dermatitis.

    Science.gov (United States)

    Kikwai, Loice; Babu, R J; Kanikkannan, Narayanasamy; Singh, Mandip

    2004-01-01

    Substance P is readily expressed in skin inflammatory disorders such as psoriasis and contact dermatitis. Spantide II is a peptide (MW 1668.76) that specifically binds to neurokinin-1 receptor (NKR-1) and blocks inflammation associated with substance P. The anti-inflammatory property of Spantide II makes it a suitable candidate to be studied as a topical formulation for the treatment of dermal inflammatory disorders. The objective of this study was to investigate the influence of pH, temperature, salt concentration and concentration on the aqueous stability of Spantide II. The stability of Spantide II was also assessed by circular dichroic (CD) spectroscopy and mass spectrometry (MS). The influence of various dermatological vehicles (ethanol, Transcutol, propylene glycol, N-methyl-2-pyrrolidone (NMP), ethyl oleate, isopropyl myristate and laurogylcol FCC (LFCC)) on the stability of Spantide II was investigated. A precise high-performance liquid chromatography (HPLC) assay was developed for analysis of Spantide II. At higher temperature (40 degrees C) the stability of Spantide II decreased with increase in pH (P 0.05). The concentration of Spantide II in the solution had no significant influence on its stability (P > 0.05). CD spectroscopy studies showed that Spantide II has a relatively stable alpha-helix structure in the liquid state. The stability of Spantide II was affected by the type of vehicle used in the study (P < 0.01) at different temperatures (P < 0.05). Spantide II at high temperature undergoes lysine-proline diketopiperazine degradation as evident in MS data. Spantide II was relatively more stable in ethyl oleate-ethanol, ethanol-water, ethanol and N-methyl-2-pyrrolidone. The results of this study indicate that ethyl oleate-ethanol (1:1) and ethanol-water (1:1) could be used as potential vehicles in the development of topical formulations of Spantide II.

  1. Post-treatment Effect of Particleboard on Dimensional Stability and Durability Properties of Particleboard Made From Sorghum Bagasse

    Science.gov (United States)

    Iswanto, A. H.; Sucipto, T.; Nadeak, S. S. D.; Fatriasari, W.

    2017-03-01

    In general, the weakness of particleboard using urea formaldehyde (UF) resin has a low dimensional stability. This reasearch intends to improve its properties by post-treatment technique using several water repellent materials. The post-treatment effect on dimensional stability and durability properties of particleboard against to subterranean and dry termites has been evaluated. Sample was dipped into water reppelent solution namely parafin, palm oil, silicon and water proof for 3 minutes. Furthermore, they were oven dried at 50°C for 24 hours. The results showed that the density varied of 0.60 to 0.74 g/cm3. The post-treatment of particleboard increases the density value. Water absorption and thickness swelling of board were varied of 29.35% to 114.99% and 13.23 to 37.31%, respectively. This treatment also improved up the thickness swelling to 65%. The best durability of board to subterranean and dry termite attack has found on silicon and waterproof treatment, respectively.

  2. Evaluation of design factors for a cascade aerator to enhance the efficiency of an oxidation pond for ferruginous mine drainage.

    Science.gov (United States)

    Oh, Chamteut; Ji, Sangwoo; Cheong, Youngwook; Yim, Giljae; Hong, Ji-Hye

    2016-10-01

    This research focused on the optimum design of a cascade aerator to enhance the efficiency of an oxidation pond in a passive treatment system for remediating ferruginous mine drainage. For this purpose, various aeration experiments with aerators of different drop heights (0-4 m) and formations (types A and B) were executed on mine drainage. Type A simply drops the mine drainage into the oxidation pond while type B sprays the mine drainage and retains it for 8 min in each step. The efficiency enhancement of the oxidation pond was strongly dependent on the increase in pH and DO of the mine drainage discharged into the pond. The water quality improved with the increase in drop height but especially showed better effect with type B. The reasons for this result were attributed to the increase of contact surface and retention time of the mine drainage. The cascade aerator, therefore, should be designed to be as high as possible with the assistance of spraying form and retention time of the mine drainage to maximize the efficiency of the oxidation pond. These effects could be evaluated by calculating required areas of the oxidation pond for 95% of Fe(2+) oxidation.

  3. Advanced reclamation of coal refuse ponds

    International Nuclear Information System (INIS)

    Honaker, R.Q.; Chugh, Y.P.; Patwardhan, A.

    1998-01-01

    A vast number of coal refuse ponds represent a significant economical resource base that may also be considered to be environmentally harmful. The fine coal fraction in a preparation plant consists of the purest particles in the entire preparation plant and, thus, if recovered, could enhance the quality of the plant product. However, until recently, the ability to effectively recover fine coal has been limited due to the lack of efficient fine particle separation technologies. As a result, a large portion of the fine coal produced in the US during this century has been disposed into refuse pond along with the acid producing components of the associated gangue material. Research conducted by Southern Illinois University scientists has found that advanced fine coal cleaning technologies can be used to recover high quality coal from refuse ponds while also utilizing a novel technique for neutralizing the acid generation potential of the pyrite-rich reject stream. Various circuitry arrangements will be discussed and metallurgical results presented in this publication

  4. Fining treatments of white wines by means of polymeric adjuvants for their stabilization against browning.

    Science.gov (United States)

    Spagna, G; Barbagallo, R N; Pifferi, P G

    2000-10-01

    Browning and maderization represent important problems for white wine stability. Essentially, this is due to polyphenol oxidation in the wine. The problem has been remedied by adsorption of polyphenol compounds with polymeric adjuvants (chitosans, scleroprotein, and polylactic acid) not used traditionally in wine-making. In particular, some chitosans reduced the polyphenol content and stabilized two Italian white wines (Trebbiano and Albana) to the same extent as did potassium caseinate, an adjuvant normally used in enology. Moreover, chitosans could be reused after a simple regeneration process.

  5. The color of melt ponds on Arctic sea ice

    Science.gov (United States)

    Lu, Peng; Leppäranta, Matti; Cheng, Bin; Li, Zhijun; Istomina, Larysa; Heygster, Georg

    2018-04-01

    Pond color, which creates the visual appearance of melt ponds on Arctic sea ice in summer, is quantitatively investigated using a two-stream radiative transfer model for ponded sea ice. The upwelling irradiance from the pond surface is determined and then its spectrum is transformed into RGB (red, green, blue) color space using a colorimetric method. The dependence of pond color on various factors such as water and ice properties and incident solar radiation is investigated. The results reveal that increasing underlying ice thickness Hi enhances both the green and blue intensities of pond color, whereas the red intensity is mostly sensitive to Hi for thin ice (Hi 1.5 m), similar to the behavior of melt-pond albedo. The distribution of the incident solar spectrum F0 with wavelength affects the pond color rather than its intensity. The pond color changes from dark blue to brighter blue with increasing scattering in ice, and the influence of absorption in ice on pond color is limited. The pond color reproduced by the model agrees with field observations for Arctic sea ice in summer, which supports the validity of this study. More importantly, the pond color has been confirmed to contain information about meltwater and underlying ice, and therefore it can be used as an index to retrieve Hi and Hp. Retrievals of Hi for thin ice (Hi < 1 m) agree better with field measurements than retrievals for thick ice, but those of Hp are not good. The analysis of pond color is a new potential method to obtain thin ice thickness in summer, although more validation data and improvements to the radiative transfer model will be needed in future.

  6. Rapid surface-water volume estimations in beaver ponds

    Science.gov (United States)

    Karran, Daniel J.; Westbrook, Cherie J.; Wheaton, Joseph M.; Johnston, Carol A.; Bedard-Haughn, Angela

    2017-02-01

    Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume-area-depth (V-A-h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

  7. Autonomous mobile platform for monitoring air emissions from industrial and municipal wastewater ponds.

    Science.gov (United States)

    Fu, Long; Huda, Quamrul; Yang, Zheng; Zhang, Lucas; Hashisho, Zaher

    2017-11-01

    Significant amounts of volatile organic compounds and greenhouse gases are generated from wastewater lagoons and tailings ponds in Alberta, Canada. Accurate measurements of these air pollutants and greenhouse gases are needed to support management and regulatory decisions. A mobile platform was developed to measure air emissions from tailings pond in the oil sands region of Alberta. The mobile platform was tested in 2015 in a municipal wastewater treatment lagoon. With a flux chamber and a CO 2 /CH 4 sensor on board, the mobile platform was able to measure CO 2 and CH 4 emissions over two days at two different locations in the pond. Flux emission rates of CO 2 and CH 4 that were measured over the study period suggest the presence of aerobic and anaerobic zones in the wastewater treatment lagoon. The study demonstrated the capabilities of the mobile platform in measuring fugitive air emissions and identified the potential for the applications in air and water quality monitoring programs. The Mobile Platform demonstrated in this study has the ability to measure greenhouse gas (GHG) emissions from fugitive sources such as municipal wastewater lagoons. This technology can be used to measure emission fluxes from tailings ponds with better detection of spatial and temporal variations of fugitive emissions. Additional air and water sampling equipment could be added to the mobile platform for a broad range of air and water quality studies in the oil sands region of Alberta.

  8. Evaluation of the wastewater from the washing of multipurpose ponds with rainbow trout farming (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Mónica Alexandra Luna Imbacuán

    2016-05-01

    Full Text Available Fish production generates two types of water flow: a continuous one related to the normal operation and an intermittent one associated to the cleaning of the seeding ponds. The multipurpose ponds (multipro are novel systems that provide advantages compared to conventional design ones, so the recent study searches to was focused to determine the physical and chemical quality and treatability of their washing effluents. The multipurpose ponds (multipro, worked to a real scale, by using initial and final seed densities of 5 kg/m3 and 8.9 kg/m3 respectively. The ponds were cleaned every 72 hours, and different samples were taken to determine the chemical-physical characteristics following the standard methods. The main results show that the effluent from cleaning represents a volume of 1.5 % of the total generated in the normal daily operation. Additionally, the effluent showed average values of 128 mg/L of total suspended solids (TSS, 94 mg/L of chemical oxygen demand (COD, 25 mg/L of biochemical oxygen demand (BOD5, 4.7 mg/L of total Kjeldahl nitrogen (NTK and 0.6 mg/L of total phosphorus (PT. The biodegradability index was 0.30, which implies a limited possibility for direct treatment by means of biological processes. It is suggested to study the primary sedimentation or filtration through a geotextile. The selection of the treatment unit is made according to the characteristics of the particles in the water column.

  9. Treatment of coke-oven wastewater with the powdered activated carbon-contact stabilization activated sludge process. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Suidan, M.T.; Deady, M.A.; Gee, C.S.

    1983-11-01

    The objective of the study was to determine optimum parameters for the operation of an innovative process train used in the treatment of coke-over wastewater. The treatment process train consisted of a contact-stabilization activated sludge system with powdered activated carbon (PAC) addition, followed by activated sludge nitrification, followed by denitrification in an anoxic filter. The control and operating parameters evaluated during the study were: (a) the average mixed-liquor PAC concentration maintained in the contact-stabilization system, (b) the solids retention time practiced in the contact-stabilization system, and (c) the hydraulic detention time maintained in the contact aeration tank. Three identical treatement process trains were constructed and employed in this study. The coke-oven wastewater used for this investigation was fed to the treatment units at 30% strength. The first part of the study was devoted to determining the interactions between the mixed liquor PAC concentration and the solids retention time in the contact-stabilization tanks. Results showed that optimum overall system performance is attainable when the highest sludge age (30 day) and highest mixed liquor PAC concentration were practiced. During the second phase of the study, all three systems were operated at a 30 day solids retention time while different detention times of 1, 2/3 and 1/3 day were evaluated in the contact tank. PAC addition rates were maintained at the former levels and, consequently, reduced contact times entailed higher mixed liquor carbon concentrations. Once again, the system receiving the highest PAC addition rate of PAC exhibited the best overall performance. This system exhibited no deterioration in process performance as a result of decreased contact detention time. 72 references, 41 figures, 24 tables.

  10. Medium-term effects of Dynesys dynamic stabilization versus posterior lumbar interbody fusion for treatment of multisegmental lumbar degenerative disease.

    Science.gov (United States)

    Wu, Haiting; Pang, Qingjiang; Jiang, Guoqiang

    2017-10-01

    Objective To compare the medium-term clinical and radiographic outcomes of Dynesys dynamic stabilization and posterior lumbar interbody fusion (PLIF) for treatment of multisegmental lumbar degenerative disease. Methods Fifty-seven patients with multisegmental lumbar degenerative disease underwent Dynesys stabilization (n = 26) or PLIF (n = 31) from December 2008 to February 2010. The mean follow-up period was 50.3 (range, 46-65) months. Clinical outcomes were evaluated using a visual analogue scale (VAS) and the Oswestry disability index (ODI). Radiographic evaluations included disc height and range of motion (ROM) of the operative segments and proximal adjacent segment on lumbar flexion-extension X-rays. The intervertebral disc signal change was defined by magnetic resonance imaging, and disc degeneration was classified by the Pfirrmann grade. Results The clinical outcomes including the VAS score and ODI were significantly improved in both groups at 3 months and the final follow-up, but the difference between the two was not significant. At the final follow-up, the disc height of stabilized segments in both groups was significantly increased; the increase was more notable in the Dynesys than PLIF group. The ROM of stabilized segments at the final follow-up decreased from 6.20° to 2.76° and 6.56° to 0.00° in the Dynesys and PLIF groups, respectively. There was no distinct change in the height of the proximal adjacent segment in the two groups. The ROM of the proximal adjacent segment in both groups increased significantly at the final follow-up; the change was significantly greater in the PLIF than Dynesys group. Only one case of adjacent segment degeneration occurred in the PLIF group, and this patient underwent a second operation. Conclusions Both Dynesys stabilization and PLIF can improve the clinical and radiographic outcomes of multisegmental lumbar degenerative disease. Compared with PLIF, Dynesys stabilization can maintain the mobility of the

  11. Remediation of the low-level radioactive waste tailing pond at Kowary, Poland

    International Nuclear Information System (INIS)

    Goerner, R.; Hartsch, J.; Koszela, J.; Krzyskow, A.; Machniewicz, B.; Sennewald, R.; Sowa, J.

    2002-03-01

    The last remaining uranium mining tailing pond in Poland, situated at Kowary, was the subject of the Kowary Tailing Pond Remediation Programme financed by Polish public bodies (70%) and by the European Commission (30%) within the framework of its programme of co-operation on radioactive waste issues with candidate countries. The EC-part of the project comprised investigations of the site, project management duties and large-scale civil works following the initial remediation planning performed by the Wroclaw University of Technology (WUT) in 1998-2000. The EC-part was contracted to G.E.O.S. Freiberg Ingenieurgesellschaft mbH following an Open Call for Tender launched by the European Commission in 1999. The following general tasks were performed in close co-operation with WUT, with the construction works subcontracted to local companies, as proposed in the Terms of Reference (TOR) of the EC-part: review of General Remediation Plan (GRP), technical design of the pond cover, construction work: internal drainage system, pond cover and site reclamation. From the information in the TOR, the following aims of remediation were defined: minimise the detrimental impact of the tailing pond on the environment, provide long-term stability of the slopes surrounding the pond, ensure the remediated site is in harmony with the surrounding natural scenery. Based on the experience gathered in similar projects, which had been running under PHARE-MCE or which belonged to the WISMUT-remediation programme in Germany, cost efficient remediation solutions were designed in close co-operation with all involved parties. They were delineated in the detailed planning documents approved in the overall remediation programme managed by WUT. The planned remediation works were prepared and performed successfully according to Polish law and in agreement with the competent local authorities. The aims of remediation were met. However, some additional tasks have been recommended in zones adjacent to the

  12. Modelisation of the contribution of sediments in the treatment process case of aerated lagoons.

    Science.gov (United States)

    Jupsin, H; Vasel, J L

    2007-01-01

    In aerated lagoons and even more in stabilization ponds the specific power (W/m3) is not high enough to maintain all the suspended solids in suspension. Some part of the suspended solids (including biomass) settles directly into the reactor and not in the final settling pond. The gradual accumulation of those sediments on the pond bottom affects performance by reducing the pond volume and shortening the Hydraulic Residence Time. However, the role played by these deposits is not restricted to such a physical effect. Far from being inert sediments they are also an important oxygen sink that must be taken into account when designing aerator power and oxygen supply, for example. On the other hand, under aerobic conditions, the upper layer of sediments may contribute to the treatment as a biofilm compartment in the reactor. In aerated lagoon systems another process contributes to the interaction of deposits and the liquid phase: the operating (often sequencing) of aerators may induce a drastic resuspension of deposits. In a 3,000 m3 aerated lagoon we evaluated that 3 tons of deposits were resuspended when aerators were started. Due to those processes we consider that a mathematical model of an aerated lagoon or of a stabilization pond has to take into account the contribution (positive and negative aspects) of deposits in the process. In this paper we propose a model for sediments including production but also biological processes. Simulations of the aerated lagoon with or without the "sediment compartment" demonstrate the effect and the importance of this compartment on the process. Of course a similar approach could be used for facultative or even maturation ponds. The next step would be to include anaerobic activities in the bottom layer.

  13. Bacterial Toxin-Triggered Drug Release from Gold Nanoparticle-Stabilized Liposomes for the Treatment of Bacterial Infection

    Science.gov (United States)

    Pornpattananangkul, Dissaya; Zhang, Li; Olson, Sage; Aryal, Santosh; Obonyo, Marygorret; Vecchio, Kenneth; Huang, Chun-Ming; Zhang, Liangfang

    2011-01-01

    We report a new approach to selectively delivering antimicrobials to the sites of bacterial infections by utilizing bacterial toxins to activate drug release from gold nanoparticle-stabilized phospholipid liposomes. The binding of chitosan modified gold nanoparticles to the surface of liposomes can effectively prevent them from fusing with one another and from undesirable payload release in regular storage or physiological environments. However, once these protected liposomes “see” bacteria that secrete toxins, the toxins will insert into the liposome membranes and form pores, through which the encapsulated therapeutic agents are released. The released drugs subsequently impose antimicrobial effects on the toxin-secreting bacteria. Using methicillin-resistant Staphycoccus aureus (MRSA) as a model bacterium and vacomycin as a model anti-MRSA antibiotic, we demonstrate that the synthesized gold nanoparticle-stabilized liposomes can completely release the encapsulated vacomycin within 24 h in the presence of MRSA bacteria and lead to inhibition of MRSA growth as effective as an equal amount of vacomycin loaded liposomes (without nanoparticle stabilizers) and free vacomycin. This bacterial toxin enabled drug release from nanoparticle-stabilized liposomes provides a new, safe and effective approach for the treatment of bacterial infections. This technique can be broadly applied to treat a variety of infections caused by bacteria that secrete pore-forming toxins. PMID:21344925

  14. Stabilization of Candida antarctica Lipase B (CALB Immobilized on Octyl Agarose by Treatment with Polyethyleneimine (PEI

    Directory of Open Access Journals (Sweden)

    Sara Peirce

    2016-06-01

    Full Text Available Lipase B from Candida antarctica (CALB was immobilized on octyl agarose (OC and physically modified with polyethyleneimine (PEI in order to confer a strong ion exchange character to the enzyme and thus enable the immobilization of other enzymes on its surface. The enzyme activity was fully maintained during the coating and the thermal stability was marginally improved. The enzyme release from the support by incubation in the non-ionic detergent Triton X-100 was more difficult after the PEI-coating, suggesting that some intermolecular physical crosslinking had occurred, making this desorption more difficult. Thermal stability was marginally improved, but the stability of the OCCALB-PEI was significantly better than that of OCCALB during inactivation in mixtures of aqueous buffer and organic cosolvents. SDS-PAGE analysis of the inactivated biocatalyst showed the OCCALB released some enzyme to the medium during inactivation, and this was partially prevented by coating with PEI. This effect was obtained without preventing the possibility of reuse of the support by incubation in 2% ionic detergents. That way, this modified CALB not only has a strong anion exchange nature, while maintaining the activity, but it also shows improved stability under diverse reaction conditions without affecting the reversibility of the immobilization.

  15. Stability of aztreonam in a portable pump reservoir used for home intravenous antibiotic treatment (HIVAT)

    NARCIS (Netherlands)

    Vinks, A A; Touw, D J; van Rossen, R C; Heijerman, H G; Bakker, W

    The stability of the monocyclic beta-lactam antibiotic aztreonam in portable pump reservoirs was studied during storage at temperatures of -20 degrees C and +5 degrees C and during drug delivery at 37 degrees C. Three 100-ml drug reservoirs and three glass containers containing 60 mg/ml aztreonam

  16. Stability of personality traits in patients who received intensive treatment for a severe eating disorder

    NARCIS (Netherlands)

    Bloks, H; Hoek, HW; Callewaert, [No Value; van Furth, E

    A longitudinal prospective design with four assessments was used to examine the stability of personality traits and their relation to recovery in patients with restrictive anorexia nervosa (N = 35), bingeing/purging anorexia nervosa (N = 37), bulimia nervosa (N = 47), and eating disorder not

  17. Morphological analysis of mouse lungs after treatment with magnetite-based magnetic fluid stabilized with DMSA

    International Nuclear Information System (INIS)

    Pereira Garcia, Monica; Miranda Parca, Renata; Braun Chaves, Sacha; Paulino Silva, Luciano; Djalma Santos, Antonio; Guerrero Marques Lacava, Zulmira; Cesar Morais, Paulo; Azevedo, Ricardo Bentes

    2005-01-01

    Mouse lungs injected with magnetic fluids based on magnetite nanoparticles stabilized by 2,3-dimercaptosuccinic acid were studied. We observed clusters of magnetic nanoparticles inside blood vessels, within the organ parenchyma and cells, as well as increased numbers of leukocytes in the organ. Both the particle concentration and organ inflammation diminished in a time-dependent manner

  18. Lip-to-incisor relationship and postorthodontic long-term stability of cover-bite treatment.

    NARCIS (Netherlands)

    Lapatki, B.G.; Baustert, D.; Schulte-Monting, J.; Frucht, S.; Jonas, I.E.

    2006-01-01

    OBJECTIVE: To investigate the impact of a persisting high lip line and other potential relapse-inducing factors on long-term stability of orthodontic correction of retroinclined maxillary central incisors. MATERIALS AND METHODS: Thirty-one cover-bite ("Deckbiss") patients with retroinclined

  19. Development of shrimp in small ponds

    Directory of Open Access Journals (Sweden)

    Armando Adolfo Ortega Salas

    2014-06-01

    Full Text Available Development of white shrimp Litopenaeus vannamei in small ponds ( 6 m3 in fresh water (2-3‰ and seawater; ponds 3.66 x 1.65 x 1.0 m; availability of fresh water, sea water, aeration and drainage. Two cycles of three months each were made. The postlarvae were acclimated to seawater fresh water in four days. Four hundred postlarvas/m3 were seeded in freshwater pond and 500 in the pool of seawater. First, a culture of Daphnia magna in the freshwater pond, also appeared chyronomid larvae; Artemia cysts were seeded in sea water as a dietary supplement. The shrimp were fed Camaronina (25% protein at libitum, daily; is offered on a tray of food; the temperature ranged between 27 and 30° C, oxygen 4.26 ± 1.43 mg / L , pH between 7 and 8 . Detritus siphoned every third day. Water changes between 10 and 20% are often performed. The feed conversion rate (FCR was 1:1.3 . The shrimp were measured in length and weight to calculate weekly growth by Bertalanffy model. Survival in the first cycle was 95.8 , and 97.9% for the second cycle. In seawater parameters of the population of the first cycle were k = 0.0301, L ∞ = 322.16 and t0 = -0.8852, the second cycle of k = 0.0203, L ∞ = 294.42 and t0 = -5.3771. The biomass of 27 kg was obtained for the first cycle and 16 kg for the second cycle. Freshwater population parameters of the first cycle were k = 0.0957, L ∞ = 146.98 and t0 = - 0.93; in the second cycle of k = 0.0172 , L ∞ = 367.82 and t0 = - 4.60. The biomass of 26 kg was obtained for the first cycle and 16 kg for the second cycle. The results indicate a rapid growth during the first 10 weeks. In small ponds can be handled well aseptic conditions without disease problems, good crop was obtained.

  20. Mechanical and Histological Effects of Resorbable Blasting Media Surface Treatment on the Initial Stability of Orthodontic Mini-Implants.

    Science.gov (United States)

    Gansukh, Odontuya; Jeong, Jong-Wha; Kim, Jong-Wan; Lee, Jong-Ho; Kim, Tae-Woo

    2016-01-01

    Introduction. This study aimed to evaluate the effects of resorbable blasting media (RBM) treatment on early stability of orthodontic mini-implants by mechanical, histomorphometric, and histological analyses. Methods. Ninety-six (64 for mechanical study and 32 for histological study and histomorphometric analysis) titanium orthodontic mini-implants (OMIs) with machined (machined group) or RBM-treated (CaP) surface (RBM group) were implanted in the tibiae of 24 rabbits. Maximum initial torque (MIT) was measured during insertion, and maximum removal torque (MRT) and removal angular momentum (RAM) were measured at 2 and 4 weeks after implantation. Bone-to-implant contact (BIC) and bone area (BA) were analyzed at 4 weeks after implantation. Results. RBM group exhibited significantly lower MIT and significantly higher MRT and RAM at 2 weeks than machined group. No significant difference in MRT, RAM, and BIC between the two groups was noted at 4 weeks, although BA was significantly higher in RBM group than in machined group. RBM group showed little bone resorption, whereas machined group showed new bone formation after bone resorption. Conclusions. RBM surface treatment can provide early stability of OMIs around 2 weeks after insertion, whereas stability of machined surface OMIs may decrease in early stages because of bone resorption, although it can subsequently recover by new bone apposition.

  1. The stability of AQT processing speed, ADAS-Cog and MMSE during acetylcholinesterase inhibitor treatment in Alzheimer's disease.

    Science.gov (United States)

    Wiig, E H; Annas, P; Basun, H; Andreasen, N; Lannfelt, L; Zetterberg, H; Blennow, K; Minthon, L

    2010-03-01

    To explore the longitudinal stability of measures of cognition during treatment with acetylcholinesterase inhibitors (AchEI) in patients with Alzheimer's disease (AD). Cognitive status was measured in a cohort of 60 patients at 6 months after initiation of treatment with AchEI (baseline) and after an additional 6 months of treatment (endpoint). A Quick Test of Cognitive Speed (AQT), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), and MMSE were administered concurrently. Correlations (rho) between age and AQT processing speed were non-significant, but were significant for ADAS-Cog and Mini Mental State Examination (MMSE). AQT and ADAS-Cog means did not differ significantly between baseline and endpoint. There was a small, significant reduction in MMSE point scores. Measures of stability (Spearman's rho) were moderate-to-high for all tests. Means for subgroups did not differ as a function of medication type. AQT processing speed, ADAS-Cog, and MMSE measures proved stable during the second 6 months of treatment with AChEI.

  2. Stabilization of Metal-Loaded Ion-Exchange Resin with a Porous Silica Supporter Through Thermal Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I-T. Park, H-S.; Yoo, J-H.; Kim, J-H.

    2003-02-25

    A new ion exchanger with porous silica as a supporting material and diphosphonic acid as a functional chelating group has been developed at ANL for the effective removal of transition metals and actinide ions from very acidic radioactive liquid wastes. The applicability of this resin for the treatment of low- and/or intermediate-level aqueous waste from nuclear power plants (NPP) has not been reported in scientific literature, but is under study now in Korea. The major radioisotopes in NPP radioactive liquid waste are Cs and Co in neutral pH ranges. This study on the thermal stabilization of metal-loaded waste resin has been carried out in parallel with the sorption experiment. Thermal treatment of metal (Co, Cs or U) loaded resin was accomplished to see the possibility of enhancing the safety and stability of the final product during transportation and disposal. In this paper, characteristics of the metal-loaded resins before and after heat treatment at three different thermal conditions were investigated and compared with each other to see the effectiveness of the thermal treatment method.

  3. Investigation on some biotic factors in carp fish ponds

    Directory of Open Access Journals (Sweden)

    D. Terziyski

    2016-03-01

    Full Text Available Abstract. Three years studies (2004 – 2006 on the main biotic parameters (chlorophyll-a, phytoplankton biomass, zooplankton biomass and bacterioplankton biomass in carp fish ponds were carried out. The aim of the study was to investigate the biotic factors and the effect of manuring on the fish ponds. The relative -1 changes in these factors in case of fertilization with manure 3000 kg.ha or without fertilization were determined. The impact of fertilization as bottom-up melioration on some biotic factors was proven by means of paired non-parametric Wilcoxon test with following significant differences: higher levels of chlorophyll-a and higher phytoplankton biomass in fertilized ponds. Zooplankton biomass was higher in fertilized ponds, but the differences were statistically insignificant. Bacterioplankton biomass was higher in the fertilized ponds, which is an indication that the applied melioration does not lead to overload of organic matter in the ponds.

  4. The western pond turtle: Habitat and history. Final report

    International Nuclear Information System (INIS)

    Holland, D.C.

    1994-08-01

    The western pond turtle is known from many areas of Oregon. The majority of sightings and other records occur in the major drainages of the Klamath, Rogue, Umpqua, Willamette and Columbia River systems. A brief overview is presented of the evolution of the Willamette-Puget Sound hydrographic basin. A synopsis is also presented of the natural history of the western pond turtle, as well as, the status of this turtle in the Willamette drainage basin. The reproductive ecology and molecular genetics of the western pond turtle are discussed. Aquatic movements and overwintering of the western pond turtle are evaluated. The effect of introduced turtle species on the status of the western pond turtle was investigated in a central California Pond. Experiments were performed to determine if this turtle could be translocated as a mitigation strategy

  5. 216-T-4 interim stabilization final report

    International Nuclear Information System (INIS)

    Smith, D.L.

    1996-01-01

    This report provides a general description of the activities performed for the interim stabilization of the 216-T-4-1 ditch, 216-T-4-2 ditch, and 216-T-4-2 pond. Interim stabilization was required to reduce the amount of surface-contaminated acres and to minimize the migration of radioactive contamination. Work associated with the 216-T4-1 ditch and 216-T-4-2 pond was performed by the Radiation Area Remedial Action (RARA) Project. Work associated with the 216-T-4-2 ditch was done concurrently but was funded by Westinghouse Hanford Company (WHC) Tank Waste Remediation Systems (TWRS)

  6. Study on method and mechanism of deep well circulation for the growth control of Microcystis in aquaculture pond.

    Science.gov (United States)

    Cong, Haibing; Sun, Feng; Wu, Jun; Zhou, Yue; Yan, Qi; Ren, Ao; Xu, Hu

    2017-06-01

    In order to control the growth of Microcystis in aquaculture ponds and reduce its adverse effect on water quality and aquaculture, a production-scale experiment of deep well circulation treatment was carried out in an aquaculture pond with water surface area of 63,000 m 2 and water depth of 1.6-2.0 m. Compared with the control pond, the experiment pond had better water quality as indicated by 64.2% reduction in chlorophyll a, and 81.1% reduction in algal cells. The chemical oxygen demand, total nitrogen, and total phosphorus concentration were reduced by 55.1%, 57.5%, and 50.8%, respectively. The treatment efficiency is mainly due to the growth control of Microcystis (i.e. cell reduction of 96.4%). The gas vesicles collapsing because of the water pressure was suggested to be the mechanism for Microcystis suppression by the deep well circulation treatment. The Microcystis lost its buoyancy after gas vesicles collapsed and it settled to the bottom of the aquaculture pond. As a result, the algae reproduction was suppressed because algae could only grow in the area with enough sunlight (i.e. water depth less than 1 m).

  7. Systems to accelerate in situ stabilization of waste deposits

    Energy Technology Data Exchange (ETDEWEB)

    Amdurer, M.; Fellman, R.T.; Roetzer, J.; Russ, C.

    1986-09-01

    In-situ systems to accelerate the stabilization of waste deposits involve three essential elements: selection of a chemical or biological agent (reactant) that can react with and stabilize the waste, a method for delivery of the reactant to the deposit, and a method for recovery of the reaction products or mobilized waste. Four reactant categories were examined: biodegradation, surfactant-assistant flushing, hydrolysis, and oxidation. Of these, biodegradation and surfactant-assisted flushing appear most promising as in-situ treatment techniques. Methods of delivery of reactants based upon gravity include surface flooding, ponding, surface spraying, ditching, and subsurface infiltration beds and galleries. Forced injection (pumping) may also be used. Permeability is an important consideration in selecting the delivery system. Recovery systems using gravity include open ditching and buried drains, and pumped methods include wellpoint and deep well systems. Basically, the same limitations that apply to delivery systems are also true for recovery systems.

  8. UV Treatment of the Stabilizing Shell for Improving the Photostability of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Silvia Rinaldi

    2016-01-01

    Full Text Available Silver nanoparticles or nanoclusters are quite sensitive to light exposure. In particular, irradiation in the localized surface plasmon resonance (LSPR region brings about a drastic modification of their optical properties due to growth and reshaping of the nanoparticles. In order to obtain luminescent colloids, small silver colloidal nanoparticles were prepared in chloroform using vinylpyrrolidone oligomers as capping agent and their luminescence properties were used to control their stability upon prolonged exposure to visible light. The polymeric shell around the metal clusters was hardened through photo-cross-linking by UV light. This process did not alter the morphology and the optical properties of the nanoparticles but greatly improved the particle photostability as confirmed also by confocal laser scanning microscopy measurements. The data clearly show that UV curing of the stabilizing layer could be a simple postsynthetic procedure to obtain materials with stable properties.

  9. Stability of magnetic fields in non-barotropic stars: an analytic treatment

    OpenAIRE

    Akgün, Taner; Reisenegger, Andreas; Mastrano, Alpha; Marchant, Pablo

    2013-01-01

    Magnetic fields in upper main-sequence stars, white dwarfs, and neutron stars are known to persist for timescales comparable to their lifetimes. From a theoretical perspective this is problematic, as it can be shown that simple magnetic field configurations are always unstable. In non-barotropic stars, stable stratification allows for a much wider range of magnetic field structures than in barotropic stars, and helps stabilize them by making it harder to induce radial displacements. Recent si...

  10. Transition in the fractal geometry of Arctic melt ponds

    Directory of Open Access Journals (Sweden)

    C. Hohenegger

    2012-10-01

    Full Text Available During the Arctic melt season, the sea ice surface undergoes a remarkable transformation from vast expanses of snow covered ice to complex mosaics of ice and melt ponds. Sea ice albedo, a key parameter in climate modeling, is determined by the complex evolution of melt pond configurations. In fact, ice–albedo feedback has played a major role in the recent declines of the summer Arctic sea ice pack. However, understanding melt pond evolution remains a significant challenge to improving climate projections. By analyzing area–perimeter data from hundreds of thousands of melt ponds, we find here an unexpected separation of scales, where pond fractal dimension D transitions from 1 to 2 around a critical length scale of 100 m2 in area. Pond complexity increases rapidly through the transition as smaller ponds coalesce to form large connected regions, and reaches a maximum for ponds larger than 1000 m2, whose boundaries resemble space-filling curves, with D ≈ 2. These universal features of Arctic melt pond evolution are similar to phase transitions in statistical physics. The results impact sea ice albedo, the transmitted radiation fields under melting sea ice, the heat balance of sea ice and the upper ocean, and biological productivity such as under ice phytoplankton blooms.

  11. CO2 Efflux from Shrimp Ponds in Indonesia

    OpenAIRE

    Sidik, Frida; Lovelock, Catherine E.

    2013-01-01

    The conversion of mangrove forest to aquaculture ponds has been increasing in recent decades. One of major concerns of this habitat loss is the release of stored 'blue' carbon from mangrove soils to the atmosphere. In this study, we assessed carbon dioxide (CO₂) efflux from soil in intensive shrimp ponds in Bali, Indonesia. We measured CO₂ efflux from the floors and walls of shrimp ponds. Rates of CO₂ efflux within shrimp ponds were 4.37 kg CO₂ m⁻² y⁻¹ from the walls and 1.60 kg CO₂ m⁻² y⁻¹ f...

  12. Avifauna of waste ponds ERDA Hanford Reservation, Benton County, Washington

    International Nuclear Information System (INIS)

    Fitzner, R.E.; Rickard, W.H.

    1975-06-01

    The presence of small ponds on the Hanford 200 Area plateau provides attractive habitats for birds. During a 29-month period, 126 bird species were observed utilizing these ponds, their associated vegetation, and air space. Waterfowls are the important agents of dispersal of radionuclides from waste ponds based on food habits, abundance, migratory habits, and importance as food in the diet of people. Abundance, long residence time, and food habits identify the American coot as the single most important species to be considered in the biological dispersal of radionuclides from waste ponds. (U.S.)

  13. Long-term warming amplifies shifts in the carbon cycle of experimental ponds

    Science.gov (United States)

    Yvon-Durocher, Gabriel; Hulatt, Chris J.; Woodward, Guy; Trimmer, Mark

    2017-02-01

    Lakes and ponds cover only about 4% of the Earth’s non-glaciated surface, yet they represent disproportionately large sources of methane and carbon dioxide. Indeed, very small ponds (for example, <0.001 km2) may account for approximately 40% of all CH4 emissions from inland waters. Understanding how greenhouse gas emissions from aquatic ecosystems will respond to global warming is therefore vital for forecasting biosphere-carbon cycle feedbacks. Here, we present findings on the long-term effects of warming on the fluxes of GHGs and rates of ecosystem metabolism in experimental ponds. We show that shifts in CH4 and CO2 fluxes, and rates of gross primary production and ecosystem respiration, observed in the first year became amplified over seven years of warming. The capacity to absorb CO2 was nearly halved after seven years of warmer conditions. The phenology of greenhouse gas fluxes was also altered, with CO2 drawdown and CH4 emissions peaking one month earlier in the warmed treatments. These findings show that warming can fundamentally alter the carbon balance of small ponds over a number of years, reducing their capacity to sequester CO2 and increasing emissions of CH4; such positive feedbacks could ultimately accelerate climate change.

  14. Tadpoles balance foraging and predator avoidance: Effects of predation, pond drying, and hunger

    Science.gov (United States)

    Bridges, C.M.

    2002-01-01

    Organisms are predicted to make trade-offs when foraging and predator avoidance behaviors present conflicting demands. Balancing conflicting demands is important to larval amphibians because adult fitness can be strongly influenced by size at metamorphosis and duration of the larval period. Larvae in temporary ponds must maximize growth within a short time period to achieve metamorphosis before ponds dry, while simultaneously avoiding predators. To determine whether tadpoles trade off between conflicting demands, I examined tadpole (Pseudacris triseriata) activity and microhabitat use in the presence of red-spotted newts (Notopthalmus viridescens) under varying conditions of pond drying and hunger. Tadpoles significantly decreased activity and increased refuge use when predators were present. The proportion of active time tadpoles spent feeding was significantly greater in predator treatments, suggesting tadpoles adaptively balance the conflicting demands of foraging and predator avoidance without making apparent trade-offs. Tadpoles responded to simulated drying conditions by accelerating development. Pond drying did not modify microhabitat use or activity in the presence of predators, suggesting tadpoles perceived predation and hunger as greater immediate threats than desiccation, and did not take more risks.

  15. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  16. Evaluation of remedial alternatives for the Solar Ponds Plume, Rocky Flats Environmental Technology Site

    International Nuclear Information System (INIS)

    Hranac, K.C.

    1998-01-01

    This paper describes the process used to select a remedial alternative for handling contaminated groundwater emanating from the Solar Evaporation Ponds (Solar Ponds) at the Rocky Flats Environmental Technology Site (RFETS) and prevent it from reaching the nearest surface water body, North Walnut Creek. Preliminary results of field investigations conducted to provide additional information for the alternatives analysis are also presented. The contaminated groundwater is referred to as the Solar Ponds Plume (SPP). The primary contaminants in the SPP are nitrate and uranium; however, some metals exceed the site action levels at several locations and volatile organic compounds, originating from other sources, also have been detected. Currently the SPP, local surface water runoff, and infiltrated precipitation are collected by a trench system located downgradient of the Solar Ponds and pumped to three storage tanks. The water (two to three million gallons annually) is then pumped to an on-site treatment plant for evaporation at an approximate cost of $7.57 per liter

  17. Feasibility of Marine Microalgae Immobilization in Alginate Bead for Marine Water Treatment: Bead Stability, Cell Growth, and Ammonia Removal

    Directory of Open Access Journals (Sweden)

    Chen-Lin Soo

    2017-01-01

    Full Text Available Sodium alginate is the most commonly used polymer matrix in microalgae immobilization for water treatment. However, the susceptibility of alginate matrixes to cation chelating agents and antigelling cation limits the use of alginates in estuarine and marine systems. Hence, the present study aims to investigate the stability of alginate bead in marine water and the feasibility of microalgae to grow when immobilized in alginate bead for marine water treatment. Different concentrations of alginate and hardening cation calcium were used to formulate beads. The beads were incubated in Guillard’s f/2 medium and shaken vigorously by using orbital shaker for 15 days. The results indicated that bead stability was enhanced by increasing alginate and CaCl2 concentrations. Subsequently, the marine microalga, Nannochloropsis sp., was immobilized in calcium alginate bead. The growth and ammoniacal-nitrogen (NH4+-N uptake by immobilized cell were compared with free cell culture in f/2 medium. Specific growth rate of immobilized cell (0.063 hr−1 was significantly higher than free cell (0.027 hr−1. There was no significant difference on specific uptake rate of free cell and immobilized cell; but immobilized cell removed significantly more NH4+-N (82.2% than free cell (47.3% culture at the end of the experiment. The present study demonstrated the potential use of alginate immobilization technique in marine microalgae culture and water treatment simultaneously.

  18. Treatment of a patient with posterior cortical atrophy (PCA) with chiropractic manipulation and Dynamic Neuromuscular Stabilization (DNS): A case report.

    Science.gov (United States)

    Francio, Vinicius T; Boesch, Ron; Tunning, Michael

    2015-03-01

    Posterior cortical atrophy (PCA) is a rare progressive neurodegenerative syndrome which unusual symptoms include deficits of balance, bodily orientation, chronic pain syndrome and dysfunctional motor patterns. Current research provides minimal guidance on support, education and recommended evidence-based patient care. This case reports the utilization of chiropractic spinal manipulation, dynamic neuromuscular stabilization (DNS), and other adjunctive procedures along with medical treatment of PCA. A 54-year-old male presented to a chiropractic clinic with non-specific back pain associated with visual disturbances, slight memory loss, and inappropriate cognitive motor control. After physical examination, brain MRI and PET scan, the diagnosis of PCA was recognized. Chiropractic spinal manipulation and dynamic neuromuscular stabilization were utilized as adjunctive care to conservative pharmacological treatment of PCA. Outcome measurements showed a 60% improvement in the patient's perception of health with restored functional neuromuscular pattern, improvements in locomotion, posture, pain control, mood, tolerance to activities of daily living (ADLs) and overall satisfactory progress in quality of life. Yet, no changes on memory loss progression, visual space orientation, and speech were observed. PCA is a progressive and debilitating condition. Because of poor awareness of PCA by physicians, patients usually receive incomplete care. Additional efforts must be centered on the musculoskeletal features of PCA, aiming enhancement in quality of life and functional improvements (FI). Adjunctive rehabilitative treatment is considered essential for individuals with cognitive and motor disturbances, and manual medicine procedures may be consider a viable option.

  19. Development of the Technologies for Stabilization Treatment of the Water of the Recycling Cooling Systems at Thermal Power Plants

    Science.gov (United States)

    Vlasov, S. M.; Chichirova, N. D.; Chichirov, A. A.; Vlasova, A. Yu.; Filimonova, A. A.; Prosvirnina, D. V.

    2018-02-01

    A turbine-condensate cooling system is one of the less stable and most hard-to-control systems of maintaining optimal water chemistry. A laboratory recycling cooling water test facility, UVO-0.3, was developed for physical simulation of innovative zero-discharge water chemistry conditions and improvement of technological flowcharts of stabilization treatment of the initial and circulating water of the recycling cooling systems at thermal power plants. Experiments were conducted in the UVO-0.3 facility to investigate the processes that occur in the recycling water supply system and master new technologies of stabilization of the initial and circulating water. It is shown that, when using untreated initial water, scaling cannot be prevented even under low concentration levels. The main reason for the activation of scale depositing is the desorption of carbon dioxide that results in alkalization of the circulating water and, as a consequence, a displacement of the chemical reaction equilibrium towards the formation of slightly soluble hardness ions. Some techniques, viz., liming and alkalization of the initial water and the by-pass treatment of the circulating water, are considered. New engineering solutions have been developed for reducing the amount of scale-forming substances in the initial and circulating water. The best results were obtained by pretreating the initial water with alkalizing agents and simultaneously bypassing and treating part of the circulating water. The obtained experimental data underlie the process flowcharts of stabilization treatment of the initial and circulating TPP water that ensure scale-free and noncorrosive operation and meet the corresponding environmental requirements. Under the bypassing, the specific rates of the agents and the residual hardness are reduced compared with the conventional pretreatment.

  20. International experience in tailings pond remediation

    International Nuclear Information System (INIS)

    Robertson, A.MacG.

    2001-01-01

    Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

  1. Comparison of phytoplankton communities in catfish split-pond aquaculture systems with conventional ponds

    Science.gov (United States)

    There has been a growing interest and use of variations of partitioned aquaculture systems (PAS) in recent years by the southeastern United States of America farmed catfish industry. Split-pond systems, one type of PAS, are designed to better manage fish waste byproducts (e.g., ammonia) and dissolv...

  2. Thermal performance experiments on ultimate heat sinks, spray ponds, and cooling ponds

    International Nuclear Information System (INIS)

    Hadlock, R.K.

    1976-12-01

    A program of measurement on a Battelle-Northwest (BNW) spray pond has been completed to prove an integrated instrumentation system for application in future field experiments. The measurement programs in the field will produce data of relevance to the design and understanding of performance for ultimate heat sinks as components of emergency core cooling systems. In the absence of active emergency cooling systems, the data will be obtained on analog systems--prime candidates among these are the naturally-occurring hot ponds at Yellowstone National Park and man-made hot cooling ponds at Savannah River National Laboratory as well as spray ponds at various industrial facilities. The proof experiment has provided data that not only illustrate the effectiveness of the instrumentation system but also display interesting site-specific heat transfer processes. The data to be obtained in the field will also be site specific but must be of generic applicability in modeling for design and performance purposes. The integrated instrumentation system will evolve, through modest modifications and substantial supplementation, to provide the requisite data for the more demanding situation of work in and about hot water

  3. Dimensional Stability of Poplar Wood by Paraffin Emulsion, Quaternary Ammonium and Hydrated Starch using Full-cell Treatment

    Directory of Open Access Journals (Sweden)

    Iraj Mansouryar

    2011-01-01

    In this study, the dimensional stabilization of poplar wood (Populus Alba by applying emulsion of paraffin, quaternary ammonium and starch was investigated. Paraffin at three levels of 0%, 3%, 5%, quaternary ammonium at three levels of 0%, 1.5%, 2.5% and starch at three levels of 0%, 1% and 2% were selected as variables. Some physical characteristics including longitudinal, tangential and radial swelling were determined. Based on the results, for optimizing physical properties, the treatment of 5% paraffin, 0-1.5% quaternary ammonium and 0-1% starch was recommended.

  4. Comparison between field data and ultimate heat-sink cooling-pond and spray-pond models

    International Nuclear Information System (INIS)

    Codell, R.

    1982-09-01

    Two previously published reports, NUREG-0693 and NUREG-0733, presented models and methods by which ultimate heat sink cooling ponds and spray ponds used for safety-related water supplies in nuclear power plants could be analyzed for design-basis conditions of heat load and meteorology. These models were only partially verified with field data. The present report compares the NRC models to data collected for NRC by Battelle Pacific Northwest Laboratories on the performance of small geothermally heated ponds and spray ponds. These comparisons generally support the conclusion that the NRC models are useful tools in predicting ultimate heat sink performance

  5. Modified Latarjet Procedure Without Capsulolabral Repair for the Treatment of Failed Previous Operative Stabilizations in Athletes.

    Science.gov (United States)

    Ranalletta, Maximiliano; Rossi, Luciano A; Bertona, Agustin; Tanoira, Ignacio; Maignon, Gastón D; Bongiovanni, Santiago L

    2018-02-03

    To analyze time to return to sport, functional outcomes, and recurrences of the modified Latarjet procedure without capsulolabral repair in athletes with recurrent anterior shoulder instability after a failed previous operative stabilization. We included athletes with recurrent anterior shoulder instability with a previous failed operative stabilization treated with the modified Latarjet procedure without capsulolabral repair with a minimum of 2-year follow-up. Return to sports, range of motion, the Rowe score, a visual analog scale for pain in sport activity, and the Athletic Shoulder Outcome Scoring System were used to assess functional outcomes. Recurrences were also evaluated. The postoperative bone block position and consolidation were assessed with computed tomography. Between June 2008 and June 2015, 68 athletes were treated with the modified Latarjet procedure without capsulolabral reconstruction for recurrent shoulder instability after a previous failed stabilization surgery. The mean follow-up was 44 months (range, 24-108 months), and the mean age at the time of operation was 26.8 years (range, 17-35 years). All the patients returned to sports, and 95% returned to the same sport they practiced before the surgery, all to the same level. No significant difference in shoulder range of motion was found between preoperative and postoperative results. The Rowe score, visual analog scale, and Athletic Shoulder Outcome Scoring System showed statistical improvement after operation (P Latarjet without capsulolabral repair produced excellent functional outcomes with most athletes returning to sport at the same level they had before the surgery without recurrences. Level IV, therapeutic, case series study. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  6. High temperature co-treatment of bottom ash and stabilized fly ashes from waste incineration

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Mogensen, E.P.B.; Lundtorp, Kasper

    2001-01-01

    Bottom ashes from two Danish municipal solid waste incineration plants were heated at 900 degreesC with iron oxide stabilized air pollution control residues at actual mass flow ratios (9:1), simulating a treating method for the residues. The two residues were cotreated, producing one combined...... stream that may be utilized as a secondary road construction material. Scanning electron microscope analysis and grain size distribution analysis indicated that sintering of the particles did not occur. Batch leaching tests at liquid/solid 10 I/kg at a range of pH-values (6-10) quantified with respect...

  7. Experimental canopy removal enhances diversity of vernal pond amphibians.

    Science.gov (United States)

    Skelly, David K; Bolden, Susan R; Freidenburg, L Kealoha

    2014-03-01

    Vernal ponds are often treated as protected environments receiving special regulation and management. Within the landscapes where they are found, forest vegetation frequently dominates surrounding uplands and can grow to overtop and shade pond basins. Two bodies of research offer differing views of the role of forest canopy for vernal pond systems. Studies of landscape conversion suggest that removing forest overstory within uplands can cause local extinctions of amphibians by altering terrestrial habitat or hindering movement. Studies of canopy above pond basins imply an opposite relationship; encroachment of overstory vegetation can be associated with local extinctions potentially via changes in light, thermal, and food resource environments. Unresolved uncertainties about the role of forest canopy reveal significant gaps in our understanding of wetland species distributions and dynamics. Any misunderstanding of canopy influences is simultaneously important to managers because current practices emphasize promoting or conserving vegetation growth particularly within buffers immediately adjacent to ponds. We evaluated this apparent contradiction by conducting a landscape-scale, long-term experiment using 14 natural vernal ponds. Tree felling at six manipulated ponds was limited in spatial scope but was nevertheless effective in increasing water temperature. Compared with eight control ponds, manipulated ponds maintained more amphibian species during five years post-manipulation. There was little evidence that any species was negatively influenced, and the reproductive effort of species for which we estimated egg inputs maintained pretreatment population densities in manipulated compared with control ponds. Overall, our experiment shows that a carefully circumscribed reduction of overhead forest canopy can enhance the capacity of vernal ponds to support wildlife diversity and suggests a scale dependence of canopy influences on amphibians. These findings have

  8. Heavy metal stabilization in contaminated soil by treatment with calcined cockle shell.

    Science.gov (United States)

    Islam, Mohammad Nazrul; Taki, Golam; Nguyen, Xuan Phuc; Jo, Young-Tae; Kim, Jun; Park, Jeong-Hun

    2017-03-01

    In several previous studies, the efficacy of various liming waste materials on the immobilization of heavy metals has been tested and it was found that soils contaminated with heavy metals can be stabilized using this technique. Since lime (CaO) has been identified as the main phase of calcined cockle shell (CCS), it was hypothesized that CCS could be used as a soil amendment to immobilize heavy metals in soil. However, to date, no studies have been conducted using CCS. In this study, the effectiveness of CCS powder on the immobilization of Cd, Pb, and Zn in mine tailing soil was evaluated. After 28 days of incubation, the treated soil samples were exposed to weathering (four cycles of freezing-thawing and four cycles of wetting-drying) for 8 days before being subjected to a leaching test. The results of this study revealed that the soil pH increased from 7.5 to 12.2 with the addition of 5% CCS. A similar soil pH was obtained when the soil was amended with 5% pure CaO. By leaching with 0.1 M HCl, extracted Cd, Pb, and Zn were reduced by up to 85, 85, and 91%, respectively. Therefore, CCS is suggested as a low-cost lime-based soil amendment for stabilizing heavy metals in abandoned mining sites.

  9. New nanomicelle curcumin formulation for ocular delivery: improved stability, solubility, and ocular anti-inflammatory treatment.

    Science.gov (United States)

    Li, Mengshuang; Xin, Meng; Guo, Chuanlong; Lin, Guiming; Wu, Xianggen

    2017-11-01

    A stable topical ophthalmic curcumin formulation with high solubility, stability, and efficacy is needed for pharmaceutical use in clinics. The objective of this article was to describe a novel curcumin containing a nanomicelle formulation using a polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (PVCL-PVA-PEG) graft copolymer. Nanomicelle curcumin was formulated and optimized and then further evaluated for in vitro cytotoxicity/in vivo ocular irritation, in vitro cellular uptake/in vivo corneal permeation, and in vitro antioxidant activity/in vivo anti-inflammatory efficacy. The solubility, chemical stability, and antioxidant activity were greatly improved after the encapsulation of the PVCL-PVA-PEG nanomicelles. The nanomicelle curcumin ophthalmic solution was simple to prepare and the nanomicelles are stable to the storage conditions, and it had good cellular tolerance. Nanomicelle curcumin also had excellent ocular tolerance in rabbits. The use of nanomicelles significantly improved in vitro cellular uptake and in vivo corneal permeation as well as improved anti-inflammatory efficacy when compared with a free curcumin solution. These findings indicate that nanomicelles could be promising topical delivery systems for the ocular administration of curcumin.

  10. Influence of Syringe Volume on Foam Stability in Sclerotherapy for Varicose Vein Treatment.

    Science.gov (United States)

    Bai, Taoping; Jiang, Wentao; Fan, Yubo

    2017-11-14

    Despite the popularity of sclerotherapy for treating varicose veins, it still exhibits various problems, such as pulmonary embolism, deep-vein thrombosis, phlebitis, and visual disorders. To investigate syringe volume influence on foam stability, obtain the foam decay rule, and provide a reference for clinics. Five types of syringes are used to prepare foam at room temperature with various liquid-gas ratios. Foam decay process experiments were performed 5 times and recorded by video. The stability indices used include drainage time, half-life, bubble diameter, bubble surface density, and drainage rate. The 30 and 2-mL syringes, respectively, recorded the highest and lowest drainage speeds. Foam drainage time and half-life, differences varied between 15 and 70 seconds, and 20 and 100 seconds, respectively. Foam bubble diameters were distributed over 0.1 to 2.0 mm with roughly 200 to 700 bubbles per square centimeter. Increased syringe volume causes the bubble diameter to increase. Thus, foam dispersion increases and foam half-life decreases; hence, foam becomes unstable. It is, thus, better to use a small syringe several times to prepare foam in clinics using segmented injections.

  11. Correlation between Thermal Treatment and Phase Transformation in Nanocrystalline Stabilized Zirconia

    Directory of Open Access Journals (Sweden)

    Tajudeen Oladele AHMED

    2013-06-01

    Full Text Available Stabilized zirconia produced via wet chemistry has chemically higher uniformity and purity. However, the grain size, particle shape, agglomerate size and specific surface area can be modified within certain degree by controlling the precipitation and sintering conditions. Generally, any physical or chemical difference between phases or effect occurring on the appearance or disappearance of a phase can be determined via thermal analysis and X-ray Diffractometry coupled with electron microscopy. In the last few decades, these materials have received tremendous attention globally in the field of defect solid-state devices. However, the challenge in this field of research has been to study thermal behaviour of these electrolytes during phase transformations and develop improved electrolytes with low activation temperature in the range of 600°C-800°C. In this paper, we report the wet chemistry of bismuth oxide stabilized zirconia having high experimental yield and low transformation temperature. Thus, the phase transformation from amorphous Zirconia to monoclinic is reported to begin above 600oC to an optimum temperature of 700oC. After calcination at 800oC for 4h, the powder have narrow particle size distribution in the range of 63-101µm. The average crystallite sizes of the synthesized powders range from 8-33nm.

  12. The critical role of islands for waterbird breeding and foraging habitat in managed ponds of the South Bay Salt Pond Restoration Project, South San Francisco Bay, California

    Science.gov (United States)

    Ackerman, Joshua T.; Hartman, C. Alex; Herzog, Mark P.; Smith, Lacy M.; Moskal, Stacy M.; De La Cruz, Susan E. W.; Yee, Julie L.; Takekawa, John Y.

    2014-01-01

    The South Bay Salt Pond Restoration Project aims to restore 50–90 percent of former salt evaporation ponds into tidal marsh in South San Francisco Bay, California. However, large numbers of waterbirds use these ponds annually as nesting and foraging habitat. Islands within ponds are particularly important habitat for nesting, foraging, and roosting waterbirds. To maintain current waterbird populations, the South Bay Salt Pond Restoration Project plans to create new islands within former salt ponds in South San Francisco Bay. In a series of studies, we investigated pond and individual island attributes that are most beneficial to nesting, foraging, and roosting waterbirds.

  13. Avaliação de desempenho de lagoa de polimento para pós-tratamento de reator anaeróbio de manta de lodo (UASB no tratamento de águas residuárias de suinocultura Evaluation of the performance of a polishing pond for the post-treatment of the effluent from an upflow anaerobic sludge blanket (UASB reactor treating swine wastewater

    Directory of Open Access Journals (Sweden)

    L.S. Rodrigues

    2009-12-01

    Full Text Available Avaliou-se o desempenho de uma lagoa de polimento, no tratamento de efluentes de águas residuárias de suinocultura de um reator anaeróbio de manta de lodo (UASB. O sistema foi composto de decantador, reator UASB, em escala real, e lagoa de polimento em escala experimental. As análises físico-químicas realizadas foram: temperatura, pH, demanda bioquímica de oxigênio (DBO, demanda química de oxigênio (DQO, sólidos suspensos totais (SST e sólidos suspensos voláteis (SSV, nitrogênio total kjedhal (NTK, nitrogênio amoniacal (N-am. e orgânico (N-org., fósforo total (Pt, coliformes totais e termotolerantes. A lagoa de polimento apresentou alto desempenho, com remoção média de 58,9% de DBO, 60,1% de NTK, 57% de N-am. e 95,34% de coliformes termotolerantes.The performance of a polishing pond for treating swine wastewater from an upflow anaerobic sludge blanket (UASB reactor was evaluated. The system was assembled with a slat settler, followed by an UASB reactor, on a real scale, and a post-treatment pond, on a demonstration scale. The following parameters were analyzed: temperature, pH, biochemical oxygen demand (BOD, chemical oxygen demand (COD, total suspended solids (TSS, volatile suspended solids (VSS, total Kjedahl nitrogen (NTK, ammonia nitrogen (N-am., organic nitrogen, total phosphorus, and total and thermotolerant coliforms. The polishing pond was highly efficient, removing an average of 58.9% of BOD, 60.1% of NTK, 57% of N-am., and 95.34% of thermotolerant coliforms.

  14. The analysis of the project for pond equipment and fish breeding

    OpenAIRE

    Salys, Mindaugas

    2013-01-01

    It is hard to imagine a Lithuanian country district with no pond. Recently the owners of the ponds more and more often select the homestead ponds which are well adapted to the amateurish fish breeding, growing and recreation. It is important, while setting such homestead ponds, to understand the biology of separate fish breeds and to realize the pond as individual and complex ecosystem. Homestead ponds and the water quality need to satisfy biological features of fish and to secure their welln...

  15. Storage Stability Improvement of Copolymer Grafted Polypropylene-AcrylicAcid (PP-AA), by means of Various After Treatment Processes

    International Nuclear Information System (INIS)

    Gitopadmojo, Isminingsih

    2000-01-01

    Polypropylene yams that have been subjected to irradiation induced graftco-polymerization with acrylic acid, have gained its moisture regain and dyeability, that fulfilled the requirement as textile material for garment.However, the copolymer grafted PP-AA has suffered from degradation in thestorage, which was indicated in the previous study that the strengthretention has dropped tremendously by photo-oxidation or photo-degradation.After treatments of PP-AA yams with chemical compound that was able toprevent further photo-oxidation, will be expected to improve the stability ofPP-AA in storage. In this research activity, the polypropylene (PP) yams weresubjected to irradiation induced graft co-polymerization by means ofγ-Ray Co-60 as irradiation source with acrylic acid (AA) as monomer.Various after treatments were subjected to the grafted PP-AA yams such asalkalisation process; dyeing (anionic dyes, cationic dyes and nonionic dyes);as well as processing with optical brightening agent and UV stabilizer,separately. The PP-AA yams (before and after treatment) were subjected tostorage from 1 month up to 42 months, and then being tested for theirmoisture regain, strength retention and elongation at breaks. The samplesbeing stored for 12 months were subjected to radical analysis. It isconcluded from the experiment that after treatment of grafted PP-AA by meansof those various processes were able to improve the stability of copolymergrafted PP-AA in storage. The presence of peroxide radical in the ESR(electron spin resonance) spectrum on PP-AA yams before treatment and theones after treated with alkaline and being stored for 12 months haveindicated the presence of photo oxidation or photo degradation, while thepresence of poly enyl radical in the ESR spectrum of after treated PP-AA withdyes having azo and azine compound as chromophore, as well as with UVstabilizer with carbonyl as chromophore and being stored for 12 months haveproved that its presence have protected such

  16. Occlusal stability in Class II, Division 1, deep bite cases followed up for many years after orthodontic treatment.

    Science.gov (United States)

    Kondo, E

    1998-12-01

    This case report analyzes long-term occlusal stability that can be achieved in Class II, Division 1, deep bite cases with active treatment finished during the period of maxillomandibular growth. The analysis was designed to identify occlusal features common to two cases at the end of active treatment and to study how the occlusion changed with growth and jaw movement to achieve stability. The following occlusal features were shared by the two cases at the end of active treatment: (1) AB plane and axes of the maxillary and mandibular posterior teeth were perpendicular to functional occlusal plane; (2) the axis of the lower incisor was almost perpendicular to DC-L1i line; (3) the anterior occlusion was overcorrected to or near an edge-to-edge relationship. Items 1 and 2 remained unchanged throughout the follow-up periods, regardless of growth status, and the overjet and overbite increased during maxillomandibular growth after treatment. During the period of mandibular growth alone, after the end of retention, the axes of maxillary incisors tipped labially; as a result, F line became parallel to CDM line by the end of growth. The labial tipping of maxillary incisors brought the lower incisal edge into contact with or extremely near the inflection point (Bp).1 By the end of growth, the tangent of Bp became parallel to or coincident with DC-L1i line and perpendicular to the axis of the lower incisor, and the DC-L1i lines at various times posttreatment were almost parallel to each other in the two cases. Overjet increased as the maxillary incisors tipped labially, providing proper protrusive and retrusive paths for mandibular guidance. The angle between the functional occlusal plane and CDM line stayed almost the same as at the end of active treatment in the two cases, suggesting a possible change in the angle of eminence in harmony with the functional occlusal plane. These factors apparently contributed to the long-term occlusal stability in the two cases.

  17. Study of the formation and thermal stability of Mg2Co obtained by mechanical alloying and heat treatment

    International Nuclear Information System (INIS)

    Martínez, Carola; Ordoñez, Stella; Serafini, Daniel; Guzmán, Danny; Rojas, Paula

    2014-01-01

    Highlights: • Study of phase evolution of elemental powders Mg and Co by MA and heat treatment. • The activation energies and apparent enthalpies for crystallization were obtained. • The phase transformation during the mechanical alloying process was determined. • The feasibility to obtain Mg 2 Co by MA plus heat treatment has been established. -- Abstract: The microstructural evolution of Mg and Co in a 2:1 atomic ratio was investigated during mechanical alloying and subsequent heat treatments. Microstructural characterization was determined using X-ray diffraction and scanning electron microscopy, while thermal stability was studied by means of differential scanning calorimetry. The results show that mechanical alloying produces amorphization and promotes greater microstructural refinement. Formation of Mg 2 Co requires an additional heat treatment at temperatures between 679 and 705 K, depending on milling time. Additionally, it was determined that the activation energy for Mg 2 Co crystallization decreases from 206 to 184 kJ/mol when the milling time increases from 12 to 36 h, respectively. Finally, a combination of the mechanical alloying process and heat treatment phase evolutions was proposed as an optimal processing route in order to obtain the Mg 2 Co compound

  18. Study of the formation and thermal stability of Mg{sub 2}Co obtained by mechanical alloying and heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, Carola, E-mail: carola.martinezu@usach.cl [Escuela de Ingeniería Mecánica, Facultad de Ingeniería, Pontificia Universidad Católica de Valparaíso, Los Carrera 01567, Casilla de correo 4059, Quilpué (Chile); Departamento de Ingeniería Metalúrgica, Facultad de Ingeniería, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 10233, Santiago (Chile); Ordoñez, Stella, E-mail: stella.ordonez@usach.cl [Departamento de Ingeniería Metalúrgica, Facultad de Ingeniería, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 10233, Santiago (Chile); Serafini, Daniel [Departamento de Física, Facultad de Ciencias, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla de correo 307, Santiago (Chile); Guzmán, Danny [Departamento de Metalurgia, Facultad de Ingeniería, Universidad de Atacama y CRIDESAT, Av. Copayapu 485, Casilla de correo 240, Copiapó (Chile); Rojas, Paula [Escuela de Ingeniería Mecánica, Facultad de Ingeniería, Pontificia Universidad Católica de Valparaíso, Los Carrera 01567, Casilla de correo 4059, Quilpué (Chile)

    2014-03-25

    Highlights: • Study of phase evolution of elemental powders Mg and Co by MA and heat treatment. • The activation energies and apparent enthalpies for crystallization were obtained. • The phase transformation during the mechanical alloying process was determined. • The feasibility to obtain Mg{sub 2}Co by MA plus heat treatment has been established. -- Abstract: The microstructural evolution of Mg and Co in a 2:1 atomic ratio was investigated during mechanical alloying and subsequent heat treatments. Microstructural characterization was determined using X-ray diffraction and scanning electron microscopy, while thermal stability was studied by means of differential scanning calorimetry. The results show that mechanical alloying produces amorphization and promotes greater microstructural refinement. Formation of Mg{sub 2}Co requires an additional heat treatment at temperatures between 679 and 705 K, depending on milling time. Additionally, it was determined that the activation energy for Mg{sub 2}Co crystallization decreases from 206 to 184 kJ/mol when the milling time increases from 12 to 36 h, respectively. Finally, a combination of the mechanical alloying process and heat treatment phase evolutions was proposed as an optimal processing route in order to obtain the Mg{sub 2}Co compound.

  19. 2101-M Pond hydrogeologic characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Chamness, M.A.; Luttrell, S.P.; Bates, D.J.; Martin, W.J.

    1990-09-01

    This report documents information collected by the Pacific Northwest Laboratory {sup (a)} at the request of Westinghouse Hanford Company. Presented in this report is the interpretation of the hydrogeologic environment at the 2101-M Pond, located in the 200-East Area of the Hanford Site. This information and its accompanying interpretation were derived from sampling and testing activities associated with the installation of four ground-water monitoring wells, in addition to data gathered from several previously existing wells. The new monitoring wells were installed as part of a groundwater monitoring program initiated in 1988. The four new monitoring wells were installed around the 2101-M Pond between May 23 and August 27, 1988. Geologic sampling, aquifer testing, and initial ground-water sampling were performed during the installation of these wells. Laboratory analyses of the sediment samples for particle size, calcium carbonate content, and selected natural and contaminant constituents were performed. A full year of quarterly ground-water sampling and the first statistical analysis of background and downgradient data have also been performed. 112 refs., 49 figs., 18 tabs.

  20. Effect of heavy metals on soil mineral surfaces and bioretention pond performance

    Science.gov (United States)

    Zhang, H.; Olson, M. S.

    2009-12-01

    Haibo Zhang and Mira S. Olson Department of Civil, Architectural, and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 As urban stormwater runoff flows across impervious surfaces, it collects and accumulates pollutants that are detrimental to the quality of local receiving water bodies. Heavy metal pollution, such as copper, lead and zinc, has been a concern in urban stormwater runoff. In addition, the presence of bacteria in stormwater has been frequently reported. The co-existence of both heavy metals and bacteria in stormwater and their complex interactions determine their transport and removal through bioretention pond. Stormwater runoff was sampled from a bioretention pond in Philadelphia, PA. The concentration of copper, lead and zinc were measured as 0.086ppm, 0.083ppm and 0.365ppm, respectively. Batch experiments were conducted with solutions of pure copper, lead and zinc, and with a synthetic stormwater solution amended with copper, lead and zinc. The solution was buffered to pH 7, within the range of the observed stormwater pH. In pure heavy metal solutions, the sorption of copper, lead and zinc onto soil are 96%, 99% and 85%, respectively. In synthetic stormwater containing nutrients and all three metals, the sorption of lead is 97%, while copper and zinc decrease to 29% and 71%, respectively. Mineralogy of a soil sample taken from the bioretention pond was analyzed using a scanning electron microscope (SEM) and compared before and after sorption experiments. Sorption and complexation of heavy metals is likely to change the mineralogy of soil particle surfaces, which will affect the attachment of bacteria and therefore its transport through soil. This study will benefit long-term predictions of the performance of bioretention ponds for urban stormwater runoff treatment. Keyword: Heavy metal pollution, sorption, surface complexation, urban stormwater runoff, bioretention pond

  1. Deadline scramble : oilsands mining operators and outsiders investigate more rapid tailings pond cleanup

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.

    2010-05-15

    Oil sand tailings ponds composed of a slurry of water, clay, sand, silt and residual bitumen have become one of the biggest environmental and public relations challenges facing the oil sand industry. The Alberta Energy Resources Conservation Board's Directive 74 requires that oilsands mining companies convert at least 20 per cent of the fine particles in their tailings ponds to solid waste by June 2011, rising to 50 per cent by 2013 and annually thereafter. Tailings ponds must be ready for surface reclamation within 5 years of the ponds becoming inactive. Directive 74 also stipulates that within 1 year of the creation of a dedicated disposal area, it must attain a minimum undrained shear strength of 5 kilopascals, rising to a minimum shear strength in 5 years of 10 kPa, trafficable and ready for reclamation. To date, only Suncor has committed to meeting the directive's deadlines. Syncrude Canada Ltd. has been testing centrifuge technology, and smaller companies, such as Solid Environmental Services Ltd, Foret Plasma Labs, LLC and Micro-TES, Inc. are also promoting their own solutions. The greatest challenge with the tailings ponds is to reach that 5 kPa rating. This article described some technologies that may attain the criteria, including the bentonite-based PitDry solidification process that is used to treat a variety of drilling, mining and industrial wastes; the Plasma Whirl, a plasma hydrocyclone that can be used for water treatment and heavy oil upgrading; and super bugs in which microbes break down hydrocarbons and other organic wastes into non-hazardous components such as fatty acids, carbon dioxide and water. 4 refs., 3 figs.

  2. A pre-enrichment step is essential for detection of Campylobacter sp. in turbid pond water.

    Science.gov (United States)

    Abulreesh, H H; Paget, T A; Goulder, R

    2014-06-01

    This work aimed to detect Campylobacter species from naturally contaminated turbid pond water by PCR. A total of 16 water samples were collected from a turbid village pond. Four methods of DNA extraction were applied to centrifuge pellets from eight 100 ml pond water samples prior to attempted detection of Campylobacter by PCR without an enrichment step. These methods were (1) Tris-HCl and sodium dodecyl sulfate followed by phenol:chloroform:isoamylalcohol extraction followed by treatment with DNA clean up kit, (2) proteinase K, (3) Chelex® 100, and (4) boiling. The other eight pond water samples (10 ml and 100 ml) were filtered and filters were incubated overnight in Preston enrichment broth. The centrifuge pellets obtained from enrichment cultures were treated by proteinase K for DNA extraction. Primers CF03 and CF04 for the flagellin genes (flaA and flaB) of Campylobacter jejuni and Campylobacter coli were used for amplifying the extracted DNA. The DNA extracted from eight-100 ml pond water samples that were not subject to selective enrichment was never amplified with primers CF03 and CF04, hence Campylobacter was not detected. In contrast, the DNA that was from samples that were subjected to a selective enrichment step in Preston broth prior to PCR assay always gave amplified bands of 340-380 bp, therefore the presence of Campylobacter was confirmed. Detection of campylobacters from naturally contaminated, turbid, environmental water may not be feasible by direct PCR assay because of low numbers and the presence of high concentration of humic matter and other PCR inhibitors. The enrichment of water samples in selective broth, however, facilitated PCR detection of Campylobacter probably by increasing cell number and by diluting PCR inhibitors.

  3. Pond bank access as an approach for managing toxic cyanobacteria in beef cattle pasture drinking water ponds.

    Science.gov (United States)

    Wilson, Alan E; Chislock, Michael F; Yang, Zhen; Barros, Mário U G; Roberts, John F

    2018-03-25

    Forty-one livestock drinking water ponds in Alabama beef cattle pastures during were surveyed during the late summer to generally understand water quality patterns in these important water resources. Since livestock drinking water ponds are prone to excess nutrients that typically lead to eutrophication, which can promote blooms of toxigenic phytoplankton such as cyanobacteria, we also assessed the threat of exposure to the hepatotoxin, microcystin. Eighty percent of the ponds studied contained measurable microcystin, while three of these ponds had concentrations above human drinking water thresholds set by the US Environmental Protection Agency (i.e., 0.3 μg/L). Water quality patterns in the livestock drinking water ponds contrasted sharply with patterns typically observed for temperate freshwater lakes and reservoirs. Namely, we found several non-linear relationships between phytoplankton abundance (measured as chlorophyll) and nutrients or total suspended solids. Livestock had direct access to all the study ponds. Consequently, the proportion of inorganic suspended solids (e.g., sediment) increased with higher concentrations of total suspended solids, which underlies these patterns. Unimodal relationships were also observed between microcystin and phytoplankton abundance or nutrients. Euglenoids were abundant in the four ponds with chlorophyll concentrations > 250 μg/L (and dominated three of these ponds), which could explain why ponds with high chlorophyll concentrations would have low microcystin concentrations. Based on observations made during sampling events and available water quality data, livestock-mediated bioturbation is causing elevated total suspended solids that lead to reduced phytoplankton abundance and microcystin despite high concentrations of nutrients, such as phosphorus and nitrogen. Thus, livestock could be used to manage algal blooms, including toxic secondary metabolites, in their drinking water ponds by allowing them to walk in the

  4. Phytoplankton Abundance and Distribution of Fish Earthen Ponds in ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2017-12-15

    Dec 15, 2017 ... influences of the physicochemical factors on diversity, distribution and abundance of phytoplankton which indirectly affects aquaculture .... culture. The only shift from this trend is in the turbidity and pH of the ponds' water which were variable (Table 2 and Fig.2). Pond 3 water with high transparency of 0.89m ...

  5. Utilization of mixed pond ash in integrated steel plant for ...

    Indian Academy of Sciences (India)

    Unknown

    tests will be helpful in persuading the local brick manu- facturers to use pond ash as a raw material. 2. Experimental. The FA and mixed FA samples were obtained from vari- ous ashes and sludge dumping ponds of Bhilai Steel. Plant, Bhilai. The samples were analysed to find out their chemical composition and loss on ...

  6. Phytoplankton productivity in newly dug fish ponds within Lake ...

    African Journals Online (AJOL)

    EJIRO

    economically justified from the conventional ones. In response to the ... Water samples were collected at 10 cm below the water surface by using a 5 L canister by lowering its suction unit into a pond. The bottles were exposed for 2 hours at 10 cm ..... turbidity and total suspended solids in the Gaba ponds as compared to the ...

  7. Fertilization of Earth Ponds. II: Effects on Plankton Communities ...

    African Journals Online (AJOL)

    Fertilization of Earth Ponds. II: Effects on Plankton Communities. J. W. WADE, H. P. STIRLING. Abstract. A study of the effects of slurry inorganic and organic of fertilizers on the production of phyto-and zooplankton in earth ponds was conducted in Central Scotland, U.K. over a period of one year. For the inorganic fertilization, ...

  8. Monitoring quantity and quality of striped catfish pond effluent

    NARCIS (Netherlands)

    Heijden, van der P.G.M.; Poelman, M.; Bosma, R.H.; Long, N.; Son, V.M.

    2012-01-01

    The production of striped catfish and other fish species in ponds has several possible impacts on the environment, one of which is caused by the discharge of pond waste water (effluent), which is enriched with nitrogen and phosphorous compounds as result of feeding and fish faeces. To restrict the

  9. Eutrophic urban ponds suffer from cyanobacterial blooms: Dutch examples

    NARCIS (Netherlands)

    Waajen, Guido W. A. M.; Faassen, Elisabeth J.; Lurling, Miquel

    2014-01-01

    Ponds play an important role in urban areas. However, cyanobacterial blooms counteract the societal need for a good water quality and pose serious health risks for citizens and pets. To provide insight into the extent and possible causes of cyanobacterial problems in urban ponds, we conducted a

  10. Feeding selectivity of wild and pond-cultured Nile tilapia ...

    African Journals Online (AJOL)

    A comparison of feeding selectivity of wild and pond-cultured Nile tilapia Oreochromis niloticus was conducted in 2008. Water and fish samples were collected in Shirati Bay, Lake Victoria, and from fish ponds in Tarime district using a La Motte water sampler and seine nets, respectively. Cyanophytes were abundant and ...

  11. Fertilization of Earth Ponds. I: Effects on Physico-Chemical ...

    African Journals Online (AJOL)

    Various biomanipulation strategies, using inorganic and organic fertilizer to improve oligotrophic conditions were carried out in earth ponds in Central Scotland U.K. over a period of one year. Replicate ponds were treated with low and high phosphorus (LP, HP) high phosphorus and nitrogen (HPN), low and high chicken ...

  12. Mathematical modeling of dissolved oxygen in fish ponds

    African Journals Online (AJOL)

    TUOYO

    thesis process to produce oxygen. When light penetration is high in the fish pond, photosynthesis takes place over the whole depth of pond, but as time goes on the growth of phytoplankton and increasing turbidity decreases light penetration, making it a limiting factor for phytoplankton growth. The function of light can be ...

  13. Public Health Implications of Aquatic Snails around Fish Ponds in ...

    African Journals Online (AJOL)

    A survey of aquatic snails around fish ponds in Okwe, Delta State was conducted to identify snails and their public health implications in the area. Snails were collected fortnightly within an hour of active snail search for a period of twelve months from randomly selected eight fish ponds using a scoop net attached to a long ...

  14. Biological removal of algae in an integrated pond system

    CSIR Research Space (South Africa)

    Meiring, PGJ

    1995-01-01

    Full Text Available A system of oxidation ponds in series with a biological trickling filter is described. It was known that this arrangement was incapable of reducing effectively the levels of algae present in the pond liquid even though nitrification was effected...

  15. Modeling the summertime evolution of sea-ice melt ponds

    DEFF Research Database (Denmark)

    Lüthje, Mikael; Feltham, D.L.; Taylor, P.D.

    2006-01-01

    We present a mathematical model describing the summer melting of sea ice. We simulate the evolution of melt ponds and determine area coverage and total surface ablation. The model predictions are tested for sensitivity to the melt rate of unponded ice, enhanced melt rate beneath the melt ponds...

  16. Heat recovery from ground below the solar pond

    NARCIS (Netherlands)

    Ganguly, S.; Date, Abhijit; Akbarzadeh, Aliakbar

    2017-01-01

    The method of heat recovery from the ground below solar ponds is investigated in the present brief note. Solar ponds lose considerable amount of heat from its bottom to the ground due to temperature gradient between them. This waste heat from ground, which is at different temperature at different

  17. Fertilization of Earth Ponds. II: Effects on Plankton Communities ...

    African Journals Online (AJOL)

    A study of the effects of slurry inorganic and organic of fertilizers on the production of phyto-and zooplankton in earth ponds was conducted in Central Scotland, U.K. over a period of one year. For the inorganic fertilization, replicate ponds were treated with low and high phosphorus (LP, HP), high phosphorus and nitrogen ...

  18. Mathematical modeling of dissolved oxygen in fish ponds ...

    African Journals Online (AJOL)

    Mathematical modeling of dissolved oxygen in fish ponds. WJS Mwegoha, ME Kaseva, SMM Sabai. Abstract. A mathematical model was developed to predict the effects of wind speed, light, pH, Temperature, dissolved carbon dioxide and chemical oxygen demand (COD) on Dissolved Oxygen (DO) in fish ponds. The effects ...

  19. Semi-aerobic stabilized landfill leachate treatment by ion exchange resin: isotherm and kinetic study

    Science.gov (United States)

    Zamri, Mohd Faiz Muaz Ahmad; Kamaruddin, Mohamad Anuar; Yusoff, Mohd Suffian; Aziz, Hamidi Abdul; Foo, Keng Yuen

    2017-05-01

    This study was carried out to investigate the treatability of ion exchange resin (Indion MB 6 SR) for the removal of chromium (VI), aluminium (III), zinc (II), copper (II), iron (II), and phosphate (PO4)3-, chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and colour from semi-aerobic stabilized leachate by batch test. A range of ion exchange resin dosage was tested towards the removal efficiency of leachate parameters. It was observed that equilibrium data were best represented by the Langmuir model for metal ions and Freundlich was ideally fit for COD, NH3-N and colour. Intra particle diffusion model, pseudo first-order and pseudo second-order isotherm models were found ideally fit with correlation of the experimental data. The findings revealed that the models could describe the ion exchange kinetic behaviour efficiently, which further suggests comprehensive outlook for the future research in this field.

  20. Conception and methodology of a prospective safety report for uranium mills tailings ponds

    International Nuclear Information System (INIS)

    Weiss, D.; Larue, J.; Fischer- Appelt, K.

    2006-01-01

    transport of contaminants into the underground. - Conclusions. Based on the results of the safety analysis it can be estimated that some kind of in-situ remediation represents the best suited option. Due to the system stabilizing features the spar cover must be preserved. The seepage water flowing out at the main dam has to be collected. The tailings pond should be replanted. The surface of the pond should be adopted to the former site morphology. (authors)

  1. Remediation of the low-level radioactive waste tailing pond in Kowary

    International Nuclear Information System (INIS)

    Waclawek, Z.

    1999-01-01

    The town of Kowary was the centre of uranium mining activities in Poland. The headquarters of the uranium mining company ZPR-1 (Zaklady Przemyslowe R-1) were located there, as it was the only uranium processing plant in Poland. Mining in Uranium in Poland ceased in 1963, but processing of low-grade dumps was continued in Kowary until 1972. As a result of these processing activities, a significant volume of wastes was produced and the tailings pond in Kowary was constructed to accommodate these wastes. The tailings pond covers an area of 1,3 ha. It is a hydrotechnical construction closed on three sides by a dam, which has been modified a number of times over the years. It is now 300 m long (the sum of the three sides)m with a maximum height of 12 m, and is at the limits of the geotechnical stability. As a result of the uranium processing activities, the tailings pond was filled with about 2,5 x 10 5 t of disposed fine-grained gneisses and schists containing about 4,5 t of uranium and about 440 GBq of radium (from processing of uranium ores). A prompt remedial action in this case is particularly necessary because the tailings pond is located in a steep mountainous valley where the local climate involves rapid summer rains with heavy erosion. The nearest buildings in the town of Kowary are located literally at the foot of the 12 m high dam and private gardens extend onto the dam slope. The urgency has recently been demonstrated during the flood of summer 1997 when the base of the dam eroded. In the early seventies, Wroclaw University of Technology (WUT) received, by a governmental decision, ownership of both the area and the facilities of the former uranium mining company ZPR-1. Subsequently, the company Hydromet, Ltd., owned by WUT, has continued to use the existing chemical plant for the various experimental processes of rare (radioactive) metals, chemical production and galvanic processes. As a result, 30 t of mixed heavy metals and 300 t of the remnants from the

  2. Radioactive EGFR Antibody Cetuximab in Multimodal Cancer Treatment: Stability and Synergistic Effects With Radiotherapy

    International Nuclear Information System (INIS)

    Rades, Dirk; Wolff, Christian; Nadrowitz, Roger; Breunig, Christian; Schild, Steven E.; Baehre, Manfred; Meller, Birgit

    2009-01-01

    Purpose: Systemic therapies when added to whole brain radiotherapy have failed to improve the survival of patients with multiple brain metastases. The epidermal growth factor receptor antibody cetuximab is an attractive option, if it is able to cross the blood-brain barrier. This might be proven with molecular imaging if the radiolabeled antibody is stable long enough to be effective. This study investigated the stability of radiolabeled cetuximab (Erbitux) ( 131 I-Erbi) and potential synergistic effects with radiotherapy in vitro. Methods and Materials: Two cell lines were investigated, A431 with numerous epidermal growth factor receptors, and JIMT without epidermal growth factor receptors. We labeled 0.4 mg cetuximab with 50 MBq of [ 131 I] iodide. Stability was determined for 72 h. The cell cultures were incubated with 131 I-Erbi or cold cetuximab for 72 h. Uptake and cell proliferation were measured every 24 h after no radiotherapy or irradiation with 2, 4, or 10 Gy. Results: The radiolabeling yield of 131 I-Erbi was always >80%. The radiochemical purity was still 93.6% after 72 h. A431 cells showed a 131 I-Erbi uptake about 100-fold greater than the JIMT controls. After 48 h, the A431 cultures showed significantly decreased proliferation. At 72 h after irradiation, 131 I-Erbi resulted in more pronounced inhibition of cell proliferation than the cold antibody in all radiation dose groups. Conclusion: 131 I-Erbi was stable for ≤72 h. Radiotherapy led to increased tumor cell uptake of 131 I-Erbi. Radiotherapy and 131 I-Erbi synergistically inhibited tumor cell proliferation. These results provide the prerequisite data for a planned in vivo study of whole brain radiotherapy plus cetuximab for brain metastases.

  3. Effects of mechanical-thermal treatments on the creep behaviour of a niobium stabilized stainless steel

    International Nuclear Information System (INIS)

    Rossi, J.L.

    1987-01-01

    The influence of microstructural variables controlled by mechanical-thermal treatments on the creep behavior of DIN-Werkstoff Nr. 1,4981 stainless steel a material candidate for use as cladding of fast breeder reactor fuel elements, was studied. The effect of the solution treatment, predeformation, predeformation plus aging and cycles of predeformation-aging, on the creep results obtained at 990 K, for applied stresses in the range 70 MPa - 310 MPa, are analysed. The results show: this material presents a creep strength superior to that show by AISI 316 stainless steel; a transition on the creep behavior is observed at a certain stress; the mechanical-thermal treatments were seen to be ineffective on the improvement of the creep strength; the pre-deformation and pre-deformation plus aging treatments were seen to induce material embrittlement whereas the cyclic treatments induced increased ductility. Transmission electron microscopy, X ray diffraction of extracted precipitates, and microanalysis were use to characterize the microstructure of this material. (author)

  4. Water Quality of Rivers and Ponds on DKI Jakarta

    Directory of Open Access Journals (Sweden)

    Diana Hendrawan

    2010-10-01

    Full Text Available Thirteen big rivers, some small rivers, and 40 ponds spread over districts at Jakarta city are potential to support human being life. As the population is growing and the usage of stream water is increasing, the condition and quality of rivers and ponds are changing. Crowd housing can affect rivers and ponds pollution, as the people awareness about clean and healthy environment is less. Stream water pollution assessment can be done by counting the effect of pollutant to life of stream water organisms. This assessment unit could be classified into physics, chemical, and biological parameter. To know the water quality, those parameters are transformed into one single value, that is Water Quality Index. The calculation result of Water Quality Index value shows that 83 % of rivers and 79 % of ponds are bad. This condition is caused by less  people and government awareness to maintain rivers and ponds.

  5. Walden Pond, Massachusetts: Environmental Setting and Current Investigations

    Science.gov (United States)

    Colman, John A.; Waldron, Marcus C.

    1998-01-01

    Introduction Walden Pond, in Concord, Massachusetts, is famous among lakes because of its unique social history. Walden was the setting for American naturalist Henry David Thoreau's well-known essay 'Walden; or, Life in the Woods,' first published in 1854. Thoreau lived and wrote at Walden Pond from July 1845 to September 1847. In 'Walden,' Thoreau combined highly admired writing on Transcendental philosophy with pioneering observations of aquatic ecology and physical aspects of limnology, the study of lakes. Because Thoreau also defended so effectively the value of living close to nature in the Walden woods, the pond is considered by many to be the birthplace of the American conservation movement. Visitors come from all over the world to the pond, which has been designated a National Historic Landmark, and its fame has resulted in a major fund drive to preserve the surrounding woods. Walden Pond has no surfacewater inflow or outflow, and much of its ground-water contributing area likely is preserved within the Walden Pond Reservation area (fig. 1). Only 15 miles from Boston, the pond is unusually clear and pristine for an urban-area lake. However, point sources of nutrients near the pond, and a large annual visitor attendance, concentrated during the summer when the swimming beach (fig. 2) is open, may contribute a nutrient load sufficient to change the pond environment. The occurrence of nuisance algal species, a recent beach closing, and an awareness of water-quality problems suffered by other ponds in the region raise concerns about the risk of ecological change at Walden Pond. Despite the role of Walden Pond as a cultural and environmental icon, little is known about the pond's ecological features, such as its internal nutrient cycling or the structure of its food web, nor have consistent measurements been made to determine whether these features are changing or are stable. Production rates of aquatic plants in lakes and ponds naturally undergo a slow increase

  6. Energy efficiency analysis of a trapezoidal solar pond

    Science.gov (United States)

    Wu, Dan; Liu, HongSheng; Jiang, Linsong; Wang, Jiansheng

    2017-12-01

    In this paper we present an investigation of the energy performance of a mini trapezoidal solar pond (with surface of 2.4m×2.4m and depth of 1.5 m) which was built in Dalian, China. The pond was filled with salty water to form the upper convective zone (UCZ), the non-convective zone (UCZ), and the lower convective zone (LCZ). Energy efficiency, the ratio of available energy to the total energy, was defined basing on the first law of thermodynamics at each zone of the solar pond. The energy efficiency of the three layers were analyzed separately accounting to the simulation results of the temperature distribution in the trapezoidal solar pond. It shows that the energy efficiency of the solar pond is relatively high at the beginning of the operation, and the energy efficiency of the UCZ is the lowest while the LCZ is the highest.

  7. The evaporation from ponds in the French Midwest

    Directory of Open Access Journals (Sweden)

    Mohammad AL DOMANY

    2013-12-01

    Full Text Available This research shows the results of a study about evaporation in five ponds in the Midwest of France. To realize this study we used climate data from the meteorological station of the Limoges-Bellegarde airport and the data of a weather station installed by us near one of the ponds. We used eight different methods to calculate the evaporation rate and we modified the Penman-Monteith method by replacing the air temperature by water temperature. To understand the role of ponds in water loss through evaporation, we proposed a hypothesis that says : if the pond did not exist, what results would we get? Based on this hypothesis we calculated the potential evapotranspiration rate taking into account the percentage of interception by vegetation. In conclusion, this study indicates that the ponds in the French Midwest present a gain of water

  8. Carbon mineralization in mine tailing ponds amended with pig slurries and marble wastes

    OpenAIRE

    Zornoza, Raul; Cano, Angel Faz; Carmona, Dora M.; Acosta, Jose A.; MartínezMartínez, Silvia; Kabas, Sebla

    2012-01-01

    Effective application of organic residues to reclaim soils requires the optimization of the waste management to minimize CO2 emissions and optimize soil C sequestration efficiency. In this study, the short-term effects of pig slurry amendment alone and together with marble waste on organic matter mineralization in two tailing ponds from Cartagena-La Unión Mining District (SE Spain) were investigated in a field remediation experiment. The treatments were: marble waste (MW), pig slurry (PS), ma...

  9. REMOVING BIOMASS FROM WATER PONDS AND SMALL WATER RESERVOIRS BY USING NON-WOVEN FILTERS

    OpenAIRE

    Jakub Nieć; Marcin Spychała; Agnieszka Ewa Ławniczak; Natalia Walczak

    2015-01-01

    Small water bodies, for example garden ponds, play many functions in the environment, including biocenotic, hydrological, climatic, sozological, landfill-creative, and aesthetic. Due to their small size, these reservoirs are sensitive to external and internal factors, they are also a common natural contaminants receivers. Nonwoven filters have been investigated for several years as a useful device for treatment of domestic wastewater pre-treated in a septic tank. The aim of this study was to ...

  10. Stabilization of arsenic and chromium polluted soils using water treatment residues

    DEFF Research Database (Denmark)

    Nielsen, Sanne Skov

    or other sorbents. Iron water treatment residues mainly consist of ferrihydrite, an oxidized iron oxy-hydroxide with a high reactivity and a large specific surface area with a high capacity for adsorption. Iron water treatment residues (Fe-WTR) are a by-product from treatment of groundwater to drinking...... in the leachate from an amended, slightly polluted soil (255 mg/kg As and 27 mg/kg Cr) did not at any time exceed 50 μg/L, which means that the soil can be reused for construction e.g. roads and baffle walls as described by the Danish Reuse Act. Ageing of ferrihydrite, the main constituent of Fe...

  11. The Effect of Homogenization Heat Treatment on Thermal Expansion Coefficient and Dimensional Stability of Low Thermal Expansion Cast Irons

    Science.gov (United States)

    Chen, Li-Hao; Liu, Zong-Pei; Pan, Yung-Ning

    2016-08-01

    In this paper, the effect of homogenization heat treatment on α value [coefficient of thermal expansion (10-6 K-1)] of low thermal expansion cast irons was studied. In addition, constrained thermal cyclic tests were conducted to evaluate the dimensional stability of the low thermal expansion cast irons with various heat treatment conditions. The results indicate that when the alloys were homogenized at a relatively low temperature, e.g., 1023 K (750 °C), the elimination of Ni segregation was not very effective, but the C concentration in the matrix was moderately reduced. On the other hand, if the alloys were homogenized at a relatively high temperature, e.g., 1473 K (1200 °C), opposite results were obtained. Consequently, not much improvement (reduction) in α value was achieved in both cases. Therefore, a compound homogenization heat treatment procedure was designed, namely 1473 K (1200 °C)/4 hours/FC/1023 K (750 °C)/2 hours/WQ, in which a relatively high homogenization temperature of 1473 K (1200 °C) can effectively eliminate the Ni segregation, and a subsequent holding stage at 1023.15 K (750 °C) can reduce the C content in the matrix. As a result, very low α values of around (1 to 2) × 10-6 K-1 were obtained. Regarding the constrained thermal cyclic testing in 303 K to 473 K (30 °C to 200 °C), the results indicate that regardless of heat treatment condition, low thermal expansion cast irons exhibit exceedingly higher dimensional stability than either the regular ductile cast iron or the 304 stainless steel. Furthermore, positive correlation exists between the α 303.15 K to 473.15 K value and the amount of shape change after the thermal cyclic testing. Among the alloys investigated, Heat I-T3B (1473 K (1200 °C)/4 hours/FC/1023 K (750 °C)/2 hours/WQ) exhibits the lowest α 303 K to 473 K value (1.72 × 10-6 K-1), and hence has the least shape change (7.41 μm) or the best dimensional stability.

  12. Heavy metal composition in stormwater and retention in ponds dependent on pond age, design and catchment type

    DEFF Research Database (Denmark)

    Egemose, Sara; Sønderup, Melanie J.; Grudinina, Anna

    2015-01-01

    Heavy metals have toxic effects on flora and fauna in the aquatic environments and are of great concern in stormwater. Heavy metal runoff was studied in 37 stormwater ponds in Denmark with varying heavy metal load, catchment type and pond design. The studied metals were Cu, Cr, Cd, Pb, Ni and Zn....

  13. Characterizing bacterial communities in tilapia pond surface sediment and their responses to pond differences and temporal variations.

    Science.gov (United States)

    Fan, Limin; Barry, Kamira; Hu, Gengdong; Meng, Shunlong; Song, Chao; Qiu, Liping; Zheng, Yao; Wu, Wei; Qu, Jianhong; Chen, Jiazhang; Xu, Pao

    2017-01-01

    Bacterial community compositions in the surface sediment of tilapia ponds and their responses to pond characteristics or seasonal variations were investigated. For that, three ponds with different stocking densities were selected to collect the samples. And the method of Illumina high-throughput sequencing was used to amplify the bacterial 16S rRNA genes. A total of 662, 876 valid reads and 5649 operational taxonomic units were obtained. Further analysis showed that the dominant phyla in all three ponds were Proteobacteria, Bacteroidetes, Chloroflexi, and Acidobacteria. The phyla Planctomycetes, Firmicutes, Chlorobi, and Spirochaetae were also relatively abundant. Among the eight phyla, the abundances of only Proteobacteria, Bacteroidetes, Firmicutes, and Spirochaetae were affected by seasonal variations, while seven of these (with the exception of Acidobacteria) were affected by pond differences. A comprehensive analysis of the richness and diversity of the bacterial 16S rRNA gene, and of the similarity in bacterial community composition in sediment also showed that the communities in tilapia pond sediment were shaped more by pond differences than by seasonal variations. Linear discriminant analysis further indicated that the influences of pond characteristics on sediment bacterial communities might be related to feed coefficients and stocking densities of genetically improved farmed tilapia (GIFT).

  14. Color stability of a resin composite: Effect of the immersion method and surface treatments

    Directory of Open Access Journals (Sweden)

    L L Miotti

    2016-01-01

    Conclusions: Specimens totally immersed in staining solutions could in somehow overestimate the color change, once that in most clinical conditions not all of the restoration surfaces are exposed to the oral environment. Moreover, as the surface sealant application produces color change values that are clinically acceptable, it might be used in esthetic restorations as an adjunct treatment.

  15. Plant wide chemical water stability modelling with PHREEQC for drinking water treatment

    NARCIS (Netherlands)

    Van der Helm, A.W.C.; Kramer, O.J.I.; Hooft, J.F.M.; De Moel, P.J.

    2015-01-01

    In practice, drinking water technologists use simplified calculation methods for aquatic chemistry calculations. Recently, the database stimela.dat is developed especially for aquatic chemistry for drinking water treatment processes. The database is used in PHREEQC, the standard in geohydrology for

  16. Predicting stabilizing treatment outcomes for complex posttraumatic stress disorder and dissociative identity disorder: an expertise-based prognostic model.

    Science.gov (United States)

    Baars, Erik W; van der Hart, Onno; Nijenhuis, Ellert R S; Chu, James A; Glas, Gerrit; Draijer, Nel

    2011-01-01

    The purpose of this study was to develop an expertise-based prognostic model for the treatment of complex posttraumatic stress disorder (PTSD) and dissociative identity disorder (DID). We developed a survey in 2 rounds: In the first round we surveyed 42 experienced therapists (22 DID and 20 complex PTSD therapists), and in the second round we surveyed a subset of 22 of the 42 therapists (13 DID and 9 complex PTSD therapists). First, we drew on therapists' knowledge of prognostic factors for stabilization-oriented treatment of complex PTSD and DID. Second, therapists prioritized a list of prognostic factors by estimating the size of each variable's prognostic effect; we clustered these factors according to content and named the clusters. Next, concept mapping methodology and statistical analyses (including principal components analyses) were used to transform individual judgments into weighted group judgments for clusters of items. A prognostic model, based on consensually determined estimates of effect sizes, of 8 clusters containing 51 factors for both complex PTSD and DID was formed. It includes the clusters lack of motivation, lack of healthy relationships, lack of healthy therapeutic relationships, lack of other internal and external resources, serious Axis I comorbidity, serious Axis II comorbidity, poor attachment, and self-destruction. In addition, a set of 5 DID-specific items was constructed. The model is supportive of the current phase-oriented treatment model, emphasizing the strengthening of the therapeutic relationship and the patient's resources in the initial stabilization phase. Further research is needed to test the model's statistical and clinical validity.

  17. Stabilization treatment of soft subgrade soil by sewage sludge ash and cement.

    Science.gov (United States)

    Chen, Li; Lin, Deng-Fong

    2009-02-15

    In this study, incinerated sewage sludge ash (ISSA) is mixed with cement in a fixed ratio of 4:1 for use as a stabilizer to improve the strength of soft, cohesive, subgrade soil. Five different ratios (in wt%: 0%, 2%, 4%, 8%, and 16%) of ISSA/cement admixture are mixed with cohesive soil to make soil samples. In order to understand the influences of admixtures on the soil properties, tests of the pH value, Atterberg limits, compaction, California bearing ratio (CBR), unconfined compressive strength, and triaxial compression were performed on those samples. The study shows that the unconfined compressive strength of specimens with the ISSA/cement addition was improved to approximately 3-7 times better than that of the untreated soil; furthermore, the swelling behavior was also effectively reduced as much as 10-60% for those samples. In some samples, the ISSA/cement additive improved the CBR values by up to 30 times that of untreated soil. This suggests that ISSA/cement has many potential applications in the field of geotechnical engineering.

  18. The Effectiveness of Silica Sand in Semi-Aerobic Stabilized Landfill Leachate Treatment

    Directory of Open Access Journals (Sweden)

    Ezlina Othman

    2010-12-01

    Full Text Available This study examines the suitability of natural silica sand as a low-cost adsorbent for the removal of ammoniacal nitrogen and heavy metals, particularly iron and zinc, from semi-aerobic stabilized landfill leachate. Leachate samples were collected from the Pulau Burung landfill site (PBLS in Penang, Malaysia. The above-mentioned contaminants are highlighted in this study because of their unsafe concentrations at PBLS. The effects of shaking time, settling time, and silica sand dosage on the study parameter removal efficiencies were investigated to predict the performance of the process. The adsorptions of ammoniacal nitrogen, iron, and zinc were judiciously described by Langmuir and Freundlich isotherm models. The optimum removal efficiencies of ammoniacal nitrogen, iron, and zinc obtained were 51%, 44.4%, and 39.2%, respectively, with a shaking time of 90 min, a settling time of 60 min, and with a dosage of 60 g (0.5 kg/L of silica sand. Based on the coefficient of determination (R2 values obtained from Langmuir and Freundlich isotherm models, ammoniacal nitrogen, iron, and zinc adsorption were better fitted to the Freundlich model.

  19. Stabilization of Pb and As in soils by applying combined treatment with phosphates and ferrous iron.

    Science.gov (United States)

    Xenidis, Anthimos; Stouraiti, Christina; Papassiopi, Nymphodora

    2010-05-15

    The chemical immobilization of Pb and As in contaminated soil from Lavrion, Greece, using monocalcium phosphate and ferrous sulfate as stabilizing agents was investigated. Monocalcium phosphate was added to contaminated soil at PO(4) to Pb molar ratios equal to 0, 0.5, 1, 1.5 and 2.5, whereas ferrous sulfate was added at Fe to As molar ratios equal to 0, 2.5, 5, 10 and 20. Phosphates addition to contaminated soil decreased Pb leachability, but resulted in significant mobilization of As. Simultaneous immobilization of Pb and As was obtained only when soil was treated with mixtures of phosphates and ferrous sulfate. Arsenic uptake by plants was also seen to increase when soil was treated only with phosphates, but co-addition of ferrous sulfate was efficient in maintaining As phytoaccumulation at low levels. The addition of at least 1.5M/M phosphates and 10M/M iron sulfate to soil reduced the dissolved levels of Pb and As in the water extracts to values in compliance with the EU drinking water standards. However, both additives contributed in the acidification of soil, decreasing pH from 7.8 to values as low as 5.6 and induced the mobilization of pH sensitive elements, such as Zn and Cd. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  20. Results of submerged sediment core sampling and analysis on Par Pond, Pond C, and L Lake: July 1995

    International Nuclear Information System (INIS)

    Koch, J.W. II; Martin, F.D.; Friday, G.P.

    1996-06-01

    Sediment cores from shallow and deep water locations in Par Pond, Pond C, and L Lake were collected and analyzed in 1995 for radioactive and nonradioactive constituents. This core analysis was conducted to develop a defensible characterization of contaminants found in the sediments of Par Pond, Pond C, and L Lake. Mercury was the only nonradiological constituent with a nonestimated quantity that was detected above the U.S Environmental Protection Agency Region IV potential contaminants of concern screening criteria. It was detected at a depth of 0.3--0.6 meters (1.0--2.0 feet) at one location in L Lake. Cesium-137, promethium-146, plutonium-238, and zirconium-95 had significantly higher concentrations in Par Pond sediments than in sediments from the reference sites. Cobalt-60, cesium-137, plutonium-238, plutonium-239/240, and strontium-90 had significantly higher concentrations in L-Lake sediments than sediments from the reference sites

  1. Par Pond phytoplankton in association with refilling of the pond: Final Report for sampling from February 1995 -- September 1996

    International Nuclear Information System (INIS)

    Wilde, E.W.; Johnson, M.A.; Cody, W.C.

    1996-01-01

    This report describes the results of phytoplankton analyses from Par Pond samples collected between February 1995 and September 1996. The principal objective of the study was to determine the effect of refilling of Par Pond following repair of the dam on the phytoplankton community. Algal blooms are often responsible for fish kills and other detrimental effects in ponds and lakes, and it was postulated that decaying vegetation from formerly exposed sediments might trigger algal blooms that could result in fish kills in Par Pond following the refill. Sporadic algal blooms involving blue-green algae were detected, especially during the summer of 1996. However, the data derived from the study demonstrates that overall, the refilling effort caused no significant negative impact to the pond attributable to phytoplankton dynamics

  2. Par Pond phytoplankton in association with refilling of the pond: Final Report for sampling from February 1995 -- September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.; Johnson, M.A.; Cody, W.C.

    1996-12-31

    This report describes the results of phytoplankton analyses from Par Pond samples collected between February 1995 and September 1996. The principal objective of the study was to determine the effect of refilling of Par Pond following repair of the dam on the phytoplankton community. Algal blooms are often responsible for fish kills and other detrimental effects in ponds and lakes, and it was postulated that decaying vegetation from formerly exposed sediments might trigger algal blooms that could result in fish kills in Par Pond following the refill. Sporadic algal blooms involving blue-green algae were detected, especially during the summer of 1996. However, the data derived from the study demonstrates that overall, the refilling effort caused no significant negative impact to the pond attributable to phytoplankton dynamics.

  3. Plant wide chemical water stability modelling with PHREEQC for drinking water treatment

    OpenAIRE

    Van der Helm, A.W.C.; Kramer, O.J.I.; Hooft, J.F.M.; De Moel, P.J.

    2015-01-01

    In practice, drinking water technologists use simplified calculation methods for aquatic chemistry calculations. Recently, the database stimela.dat is developed especially for aquatic chemistry for drinking water treatment processes. The database is used in PHREEQC, the standard in geohydrology for calculating chemical equilibria in groundwater. The development of a graphical user interface for PHREEQC in Microsoft Excel has made it possible to easily incorporate complicated chemical calculat...

  4. Microbiological stabilization of Aloe vera (Aloe barbadensis Miller) gel by high hydrostatic pressure treatment.

    Science.gov (United States)

    Reyes, Juan E; Guanoquiza, Manuel I; Tabilo-Munizaga, Gipsy; Vega-Galvez, Antonio; Miranda, Margarita; Pérez-Won, Mario

    2012-09-03

    The effect of high hydrostatic pressure (HHP) treatment (300, 400 and 500 MPa for 1 and 3 min at 20 °C) on the microbiological shelf-life and microbiota composition of Aloe vera gel during 90 days of storage at 4 °C was investigated. Aerobic mesophilic and psychrotrophic bacteria, as well as moulds and yeasts, were enumerated after HHP treatment and through cold storage. Randomly selected isolates from the count plates were identified by standard methods and the API identification system. Results showed that HHP treatment at or over 400 MPa for 3 min were effective to keep the microbial counts to undetectable levels during the whole storage period, and consequently the microbiological shelf-life of A. vera gel was extended for more than 90 days at 4 °C. The microbiota in the untreated A. vera gel was dominated by Gram-negative bacteria (mostly Rahnella aquatilis) and yeasts (mostly Rhodotorula mucilaginosa). In contrast, Gram-positive bacteria tentatively identified as Arthrobacter spp. and Micrococcus/Kocuria spp. were the predominant microorganisms in samples pressurized at 300 MPa for 1 and 3 min, while Bacillus megaterium predominating in samples treated at 400 MPa for 1 min. At 400 MPa for 3 min and above, the microbial growth was completely suppressed during at least 90 days; however, viable spore-formers were detected by enrichment. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Mapping QTLs associated to germination stability following dry-heat treatment in rice seed.

    Science.gov (United States)

    Lee, Seung-Yeob; Kim, Yong-Hwan; Lee, Gang-Seob

    2017-07-01

    Using 164 recombinant inbred lines (RILs) derived from a cross between Milyang 23 (indica/japonica) and Gihobyeo (japonica) in rice, dry-heat tolerance was evaluated for the seeds of parents and RILs, whose dormancy was naturally broken in six months after harvesting. Mapping QTLs associated to dry-heat tolerance was carried out through interval mapping using Qgene 3.0. Seed germination after dry-heat treatments (90 °C for 24 h) showed a significant difference between the two parents, when evaluated for percentage germination and mean germination time. Milyang 23 was highly tolerant to the dry-heat treatment, while Gihobyeo was sensitive. Three QTLs (qDHT 1, qDHT 5, and qDHT 7) conferring the dry-heat tolerance were mapped to chromosomes 1, 5 and 7, respectively. qDHT 1 on chromosome 1 was tightly linked at 4 cM from ME1-1. The phenotypic variation explained by the three QTLs was 27.18% of the total variance in the 164 RIL populations, and the parental additive effects of three QTLs affected the Milyang 23 allele increased dry-heat tolerance. The detection of new QTLs associated with dry-heat tolerance will provide important information for disease and insect control, using dry-heat treatment in organic or low input sustainable agriculture.

  6. Data validation report for the 100-D Ponds Operable Unit: 100-D ponds sampling

    International Nuclear Information System (INIS)

    Stankovich, M.T.

    1994-01-01

    Westinghouse-Hanford has requested that 100 percent of the Sample Delivery Groups be validated for the 100-D Ponds Operable Unit Sampling Investigation. Therefore the data from the chemical analysis of all 30 samples from this sampling event and their related quality assurance samples were reviewed and validated to verify that reported sample results were of sufficient quality to support decisions regarding remedial actions performed at this site

  7. Percutaneous Stabilization System Osseofix® for Treatment of Osteoporotic Vertebral Compression Fractures - Clinical and Radiological Results after 12 Months.

    Directory of Open Access Journals (Sweden)

    Stephan Albrecht Ender

    Full Text Available A prospective consecutive cohort study (follow-up study.Our study investigated whether implantation of an expandable titanium mesh cage (Osseofix® is a successful and safe minimally invasive therapy for osteoporotic vertebral compression fractures (VCF. Our experiences, clinical and radiological findings after 12 months follow-up are presented. Kypho- and vertebroplasty are well-established minimally invasive procedures for the treatment of osteoporotic VCF. The main complications associated with both procedures are uncontrolled bone cement leakage. Therefore a suitable alternative has been investigated.During June 2010 to May 2011 24 patients were included with 32 osteoporotic VCF (T6 to L4. All of them were stabilized with the Osseofix® system. Preinterventionally we performed X-ray, MRI, and bone density measurements (DXA. Clinical and radiological results were evaluated preop., postop. and after 12 months postop. based on the Oswestry Disability Index (ODI and the Visual Analogue Scale (VAS, X-ray (Beck Index, Cobb-angle and CT.There was a significant improvement in the mean ODI (70,6% to 30,1% as well as a significant reduction in pain intensity (VAS (7,7 to 1,4 after 12 month. The mean kyphotic angle according to Cobb showed significant improvements (11,7° to 10,4° after 12 months. Postinterventional imaging showed only one case of loss of height in a stabilized vertebral body (3.1%. We saw no changes in posterior vertebral wall or adjacent fractures. Except for one pronounced postoperative hematoma we saw no surgical complications including no cement leakage.Stabilization of symptomatic osteoporotic VCF with Osseofix® system is a safe and effective procedure, even in fractures with posterior wall involvement. The clinical mid-term results are good at a very low complication rate. The Osseofix® system is an interesting alternative to the established procedures of cement augmentation.

  8. Metal sulfide nanoparticles synthesized via enzyme treatment of biopolymer stabilized nanosuspensions

    Science.gov (United States)

    Kim, Yi-Yeoun; Walsh, Dominic

    2010-02-01

    Nanoparticles of CuS, CuxS, Ag2S and CdS were successfully prepared using a novel general and green synthetic process to give dextran biopolymer stabilised metal sulfifde nanosuspensions. Following preparation, dextranase enzyme was used to remove the bulk of the bound dextran to give pure stable metal sulfide nanocrystals for application in for example aspects of medicine, photonics and solar cells. Particles of good homogeneity were obtained and the CuS nanoparticle size was controlled to 9-27 nm by adjusting the reaction conditions. Cu2S nanoparticles were 14 nm, Ag2S nanoparticles were 20-50 nm and CdS nanoparticles were 9 nm is size. The complexing mechanism of nanoparticle sulfides to dextrans was further studied using carboxylmethyl dextran as a complexing agent and crosslinked Sephadex (dextran) `beads as substrate. Particles were characterized by TEM, XRD, TGA, FT-IR and zeta-potential measurement, and their UV-vis spectroscopic absorption properties were determined. Stabilization of the sulfide nanoparticles with soluble hydroxylated biopolymers such as dextran is previously unreported and is here interpreted in terms of viscosity, pH of the system and weak polar S-H or S(metal)OH2+ interactions with dextran depending on the material. Notably, the complexing mechanism appears to differ significantly from that taking place in known dextran-metal oxide systems. The process shown here has good potential for scale-up as a biosynthetic route for a range of functional sulfide nanoparticles.Nanoparticles of CuS, CuxS, Ag2S and CdS were successfully prepared using a novel general and green synthetic process to give dextran biopolymer stabilised metal sulfifde nanosuspensions. Following preparation, dextranase enzyme was used to remove the bulk of the bound dextran to give pure stable metal sulfide nanocrystals for application in for example aspects of medicine, photonics and solar cells. Particles of good homogeneity were obtained and the CuS nanoparticle size

  9. Predicted buffer zones to protect temporary pond invertebrates from ground-based insecticide applications against desert locusts.

    NARCIS (Netherlands)

    Lahr, J.; Gadji, B.; Dia, D.

    2000-01-01

    To estimate safe downwind distances (i.e. buffer zone widths) for temporary ponds from ULV-treatments with current locust insecticides, experimental trials with two ground-based sprayers, the hand-held Micro-Ulva® and the vehicle-mounted Ulva-Mast® X15 Mark I, were conducted with fenitrothion

  10. Performance evaluation of four different methods for circulating water in commercial-scale, split-pond aquaculture systems

    Science.gov (United States)

    The split-pond consists of a fish-culture basin that is connected to a waste-treatment lagoon by two conveyance structures. Water is circulated between the two basins with high-volume pumps and many different pumping systems are being used on commercial farms. Pump performance was evaluated with fou...

  11. CO2 Efflux from Shrimp Ponds in Indonesia

    Science.gov (United States)

    Sidik, Frida; Lovelock, Catherine E.

    2013-01-01

    The conversion of mangrove forest to aquaculture ponds has been increasing in recent decades. One of major concerns of this habitat loss is the release of stored ‘blue’ carbon from mangrove soils to the atmosphere. In this study, we assessed carbon dioxide (CO2) efflux from soil in intensive shrimp ponds in Bali, Indonesia. We measured CO2 efflux from the floors and walls of shrimp ponds. Rates of CO2 efflux within shrimp ponds were 4.37 kg CO2 m−2 y−1 from the walls and 1.60 kg CO2 m−2 y−1 from the floors. Combining our findings with published data of aquaculture land use in Indonesia, we estimated that shrimp ponds in this region result in CO2 emissions to the atmosphere between 5.76 and 13.95 Tg y−1. The results indicate that conversion of mangrove forests to aquaculture ponds contributes to greenhouse gas emissions that are comparable to peat forest conversion to other land uses in Indonesia. Higher magnitudes of CO2 emission may be released to atmosphere where ponds are constructed in newly cleared mangrove forests. This study indicates the need for incentives that can meet the target of aquaculture industry without expanding the converted mangrove areas, which will lead to increased CO2 released to atmosphere. PMID:23755306

  12. Stability of skeletal changes induced by growth modulation procedures in the treatment of skeletal Class II malocclusion

    Directory of Open Access Journals (Sweden)

    Prashantha Govinakovi Shivamurthy

    2016-01-01

    Full Text Available Objective: Objective of this study, based on an evaluation of lateral cephalograms, was to evaluate the degree of skeletal changes produced by the various growth modulative procedures in the treatment of skeletal Class II malocclusion and to characterize the stability of these changes in the years after treatment. Materials and Methods: Total of 40 patients with Class II malocclusion was divided into three groups according to appliance used, i.e. removable or fixed functional appliances (n = 10, combination of functional appliance with headgear (n = 10, and only headgear (n = 10. In addition, almost a matched control group (n = 10 also characterized by skeletal Class II pattern and were under observation, for more than 2 years was also selected. Lateral cephalograms of each patient were taken at the start of treatment (T1, at its completion (T2, and long-term posttreatment (T3. Results: This study showed significant improvement in maxillomandibular relationship in treated group compared to control group, and the changes remained stable in posttreatment phase. Restriction of maxillary growth was evident in headgear and combination groups whereas significant forward movement of the mandible was seen in functional group. Conclusion: Analysis of lateral cephalograms indicates that growth modulation therapy in angle Class II malocclusion brings about desired skeletal changes which remain relatively stable over a long-term period.

  13. Fate of polybrominated diphenyl ethers during wastewater treatment/polishing and sludge stabilization/disposal.

    Science.gov (United States)

    Arnold, Robert G; Teske, Sondra; Tomanek, Matt; Engstrom, Jason; Leung, Cary; Zhang, Jianmin; Banihani, Qais; Quanrud, David; Ela, Wendell P; Sáez, A Eduardo

    2008-10-01

    Large quantities of polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in clothing and plastic products since the 1970s. A small fraction of the PBDEs in manufactured products subsequently enters municipal wastewater. Nevertheless, the resistance of these compounds to chemical and biochemical transformations provides opportunities for accumulation in sediments that are in contact with wastewater effluent and agricultural soils that are amended with biosolids derived from wastewater treatment. Balances developed for PBDE congeners indicate that conventional wastewater treatment processes and soil infiltration of treated wastewater in recharge operations do not discriminate significantly among the major congeners in commercially available PBDE products. Accumulation of PBDEs at near part-per-million levels was measured in the surface sediments at the Sweetwater Recharge Facility in Tucson, Arizona, during 10-15 years of operation. Half-lives for loss of major PBDE congeners from sediments were decades or longer. Local agricultural soils amended with biosolids over a 20-year period showed similar accumulation of PBDEs. The widespread use of PBDEs in commercial products, compound persistence, and toxicity indicate that additional effort is warranted to better understand fate-determining processes for PBDEs in the environment.

  14. Monthly and diurnal variations of limnological conditions of two ponds

    Directory of Open Access Journals (Sweden)

    AKM Fazlur Rahaman

    2017-06-01

    Full Text Available A study on monthly and diurnal changes of limnological conditions of two ponds was conducted in the Bangladesh Agricultural University campus, Mymensingh. The research work was performed by studying the limnological parameters such as transparency, temperature, dissolved oxygen, free carbon dioxide, pH, total alkalinity, nitrate-nitrogen, phosphate-phosphorus and plankton. Diurnal variations of physico-chemical factors were studied fortnightly at 6 hrs intervals at 6 a.m., 12 noon, 6 p.m. and 12 midnight. The amounts of transparency, dissolved oxygen and pH were higher during winter months than in summer months in both the ponds. Transparency, water temperature, total alkalinity, NO3-N and PO4-P were higher during summer months than in winter months in both the ponds. But the amount of free carbon dioxide was higher during winter months than in summer months in pond 1 while in pond 2 the amount of free carbon dioxide was higher during summer months than in winter months. Qualitative and quantitative monthly variations of phytoplankton and zooplankton were observed in both the ponds during the study period. The highest amount of dissolved oxygen, pH and total alkalinity were recorded at 6 p.m. and the lowest amounts of those at 6 a.m. in both the ponds. The highest temperature was recorded at 12 noon and the lowest at 12 midnight. But the highest amount of free carbon dioxide was recorded at 6 a.m. and the lowest at 6 p.m. in both the ponds. All the factors showed appreciable diel variations throughout the study period, which indicate that the ponds are productive.

  15. Sulfur polymer stabilization/solidification (SPSS) treatment of mixed waste mercury recovered from environmental restoration activities at BNL

    International Nuclear Information System (INIS)

    Kalb, P.; Adams, J.; Milian, L.

    2001-01-01

    Over 1,140 yd 3 of radioactively contaminated soil containing toxic mercury (Hg) and several liters of mixed-waste elemental mercury were generated during a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) removal action at Brookhaven National Laboratory (BNL). The US Department of Energy's (DOE) Office of Science and Technology Mixed Waste Focus Area (DOE MWFA) is sponsoring a comparison of several technologies that may be used to treat these wastes and similar wastes at BNL and other sites across the DOE complex. This report describes work conducted at BNL on the application and pilot-scale demonstration of the newly developed Sulfur Polymer Stabilization/Solidification (SPSS) process for treatment of contaminated mixed-waste soils containing high concentrations (approximately 5,000 mg/L) of mercury and liquid elemental mercury. BNL's SPSS (patent pending) process chemically stabilizes the mercury to reduce vapor pressure and leachability and physically encapsulates the waste in a solid matrix to eliminate dispersion and provide long-term durability. Two 55-gallon drums of mixed-waste soil containing high concentrations of mercury and about 62 kg of radioactive contaminated elemental mercury were successfully treated. Waste loadings of 60 wt% soil were achieved without resulting in any increase in waste volume, while elemental mercury was solidified at a waste loading of 33 wt% mercury. Toxicity Characteristic Leaching Procedure (TCLP) analyses indicate the final waste form products pass current Environmental Protection Agency (EPA) allowable TCLP concentrations as well as the more stringent proposed Universal Treatment Standards. Mass balance measurements show that 99.7% of the mercury treated was successfully retained within the waste form, while only 0.3% was captured in the off gas system

  16. Sulfur polymer stabilization/solidification (SPSS) treatment of mixed waste mercury recovered from environmental restoration activities at BNL

    Energy Technology Data Exchange (ETDEWEB)

    Kalb, P.; Adams, J.; Milian, L.

    2001-01-29

    Over 1,140 yd{sup 3} of radioactively contaminated soil containing toxic mercury (Hg) and several liters of mixed-waste elemental mercury were generated during a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) removal action at Brookhaven National Laboratory (BNL). The US Department of Energy's (DOE) Office of Science and Technology Mixed Waste Focus Area (DOE MWFA) is sponsoring a comparison of several technologies that may be used to treat these wastes and similar wastes at BNL and other sites across the DOE complex. This report describes work conducted at BNL on the application and pilot-scale demonstration of the newly developed Sulfur Polymer Stabilization/Solidification (SPSS) process for treatment of contaminated mixed-waste soils containing high concentrations ({approximately} 5,000 mg/L) of mercury and liquid elemental mercury. BNL's SPSS (patent pending) process chemically stabilizes the mercury to reduce vapor pressure and leachability and physically encapsulates the waste in a solid matrix to eliminate dispersion and provide long-term durability. Two 55-gallon drums of mixed-waste soil containing high concentrations of mercury and about 62 kg of radioactive contaminated elemental mercury were successfully treated. Waste loadings of 60 wt% soil were achieved without resulting in any increase in waste volume, while elemental mercury was solidified at a waste loading of 33 wt% mercury. Toxicity Characteristic Leaching Procedure (TCLP) analyses indicate the final waste form products pass current Environmental Protection Agency (EPA) allowable TCLP concentrations as well as the more stringent proposed Universal Treatment Standards. Mass balance measurements show that 99.7% of the mercury treated was successfully retained within the waste form, while only 0.3% was captured in the off gas system.

  17. FROM PONDS TO MAN-MADE SEAS IN RUSSIA

    Directory of Open Access Journals (Sweden)

    Sergey Gorshkov

    2013-01-01

    Full Text Available Russia has more than 2200 reservoirs and large ponds. As time went by, ponds lost their importance in some aspects of human life, while newly created man-made seas impacted the nature and the people in two ways. The costs involved in designing, constructing, and operating the artificial seas, especially on the plains, have been too high to consider them as an undisputed achievement of the Soviet scientists transforming the nature. This paper discusses the problem of ponds and man-made seas in Russia.

  18. Limnological database for Par Pond: 1959 to 1980

    Energy Technology Data Exchange (ETDEWEB)

    Tilly, L.J.

    1981-03-01

    A limnological database for Par Pond, a cooling reservoir for hot reactor effluent water at the Savannah River Plant, is described. The data are derived from a combination of research and monitoring efforts on Par Pond since 1959. The approximately 24,000-byte database provides water quality, primary productivity, and flow data from a number of different stations, depths, and times during the 22-year history of the Par Pond impoundment. The data have been organized to permit an interpretation of the effects of twenty years of cooling system operations on the structure and function of an aquatic ecosystem.

  19. Limnological database for Par Pond: 1959 to 1980

    International Nuclear Information System (INIS)

    Tilly, L.J.

    1981-03-01

    A limnological database for Par Pond, a cooling reservoir for hot reactor effluent water at the Savannah River Plant, is described. The data are derived from a combination of research and monitoring efforts on Par Pond since 1959. The approximately 24,000-byte database provides water quality, primary productivity, and flow data from a number of different stations, depths, and times during the 22-year history of the Par Pond impoundment. The data have been organized to permit an interpretation of the effects of twenty years of cooling system operations on the structure and function of an aquatic ecosystem

  20. Post-treatment and reuse of secondary effluents using natural ltreatment systems: the Indian practices.

    Science.gov (United States)

    Kumar, D; Asolekar, S R; Sharma, S K

    2015-10-01

    Paper summarizes the results of India-wide survey of natural treatment systems (NTSs) for wastewater treatment and reuse. The quality of treated wastewater from different types of NTSs was analyzed for various physico-chemical and bacteriological parameters, and needs for post-treatment were identified. Currently, about 1838 million liters per day (MLD) of wastewater is being treated using NTSs, of which the contributions of polishing ponds, waste stabilization ponds, duckweed ponds, constructed wetlands, and Karnal technology were found to be 53.39, 45.15, 0.13, 0.55, and 0.78%, respectively. Among the NTSs studied, constructed wetland was found most efficient in removal of pollutants including nitrogen, phosphorus, total coliform, and fecal coliform in the range of 76, 61, 99.956, and 99.923%, respectively. Of all types of NTSs, only constructed wetland was found to meet the total coliform count requirements (effluents for irrigation; effluents from 48 systems are being discharged into river or lake, and remaining 38 systems have not found any designated use of treated effluent. The chlorination was the only post-treatment, which is being practiced at only three wastewater treatment facilities. During post-treatment, 1-2 ppm of chlorine is applied to the secondary effluent irrespective of its quality. The treated effluents from different NTSs contain fecal bacteria in the magnitude of 10(3) to 10(5), which may cause the severe health impacts through contamination of groundwater as well as surface water resources.