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Sample records for water works filter

  1. Conversion of sand filters into activated carbon filters at the La Presa (Valencia) water works; Conversion de filtros de arena porcarbon activo en la ETAP de La Presa (Valencia)

    Energy Technology Data Exchange (ETDEWEB)

    Macian Cervera, V. J.; Monforte Monleon, L.; Ribera Orts, R.; Suris Jorda, J. I.; Klee, J. M.

    2007-07-01

    To improve the water quality at potable water treatment plant of La P esa (Valencia), the sand filters have been replaced for activated carbon filters. In the following review the results and conclusions of the direct sand filter conversion into activated carbon filters will be presented. The leads to a simple and fast solution to odour and taste removal, as well as dissolved organic matter, without investments in works at the water works. (Author)

  2. Biodegradation of gasoline compounds (BTEX) in a water works sand filter

    DEFF Research Database (Denmark)

    Arvin, Erik; Engelsen, P.; Sebber, U.

    2004-01-01

    Various chemical compounds including aromatic gasoline compounds frequently contaminate drinking water wells in urban areas. Because ground water treatment is simple, usually consisting of aeration/stripping and sand-filtration, it is of significant interest to know the ability of the conventional...... treatment to remove the chemical contaminants. The removal of gasoline compounds was investigated in a two-stage pilot scale sand filter, each with a filter depth of 0.8-1 m and with a filtration rate of 7.6 m/h. The concentrations of aromatic compounds were in the range 7-15 mu g/L, which are realistically...... sand grains). Influent iron concentrations in the range 0-4 mg/L and backwashing did not adversely affect the biodegradation of hydrocarbons. This study has shown that a conventional biological active sand filter can act as an efficient barrier against gasoline compounds, thereby saving the consumer...

  3. Insights into the working mechanism of water filtered infrared A (wIRA) irradiation on Chlamydia trachomatis serovar E

    Science.gov (United States)

    Kuratli, Jasmin; Pesch, Theresa; Marti, Hanna; Blenn, Christian; Borel, Nicole

    2018-02-01

    Infections with Chlamydia trachomatis are the major cause for infectious blindness and still represent the most common bacterial sexually transmitted disease worldwide. Considering the possible side effects of antibiotic therapy and the increasing threat of antibiotic resistance, alternative therapeutic strategies are needed. Previous studies showed a reduction of C. trachomatis infectivity after irradiation with water filtered infrared A alone (wIRA) or in combination with visible light (wIRA/VIS). In this study, we aimed to gain further insight into the working mechanism of wIRA/VIS by analyzing cytokine and chemokine levels of infected and non-infected HeLa cells following triple dose irradiation at 24, 36 and 40 hours post infection. Subsequently, we examined the influence of cytokines on irradiation and chlamydial infection using a cytokine/chemokine inhibitor (Azelastine) and by IL-6 and IL-8 gene silencing. A triple dose irradiation significantly reduced chlamydial infectivity in HeLa cells without inducing the chlamydial stress response. The reducing effect was present regardless of the addition of cycloheximide (CHX), a host protein synthesis inhibitor. Chlamydial infection, wIRA/VIS treatment and the combination of both revealed a similar release pattern of a subset of pro-inflammatory cytokines (IL-6, IL-8, RANTES, Serpin E1). The addition of Azelastine induced the chlamydial stress response in non-irradiated samples. This effect was even more pronounced in wIRA/VIS-treated conditions. Silencing of IL-6 and IL-8 resulted in a lower chlamydial infectivity. However, wIRA/VIS treatment of infected and silenced cells reduced the chlamydial infectivity similar to wIRA/VIS treated control cells. Further studies are needed to elucidate the working mechanism of wIRA/VIS.

  4. Cryptosporidium: A Guide to Water Filters

    Science.gov (United States)

    ... Tap Water Many but not all available home water filters remove Cryptosporidium . Some filter designs are more suitable for removal of Cryptosporidium than others. Filters that have the words "reverse osmosis" on the label protect against Cryptosporidium . Some other ...

  5. Rotating Ceramic Water Filter Discs System for Water Filtration

    Directory of Open Access Journals (Sweden)

    Riyadh Z. Al Zubaidy

    2017-04-01

    Full Text Available This work aimed to design, construct and operate a new laboratory scale water filtration system. This system was used to examine the efficiency of two ceramic filter discs as a medium for water filtration. These filters were made from two different ceramic mixtures of local red clay, sawdust, and water. The filtration system was designed with two rotating interfered modules of these filters. Rotating these modules generates shear force between water and the surfaces of filter discs of the filtration modules that works to reduce thickness of layer of rejected materials on the filters surfaces. Each module consists of seven filtration units and each unit consists of two ceramic filter discs. The average measured hydraulic conductivity of the first module was 13.7mm/day and that for the second module was 50mm/day. Results showed that the water filtration system can be operated continuously with a constant flow rate and the filtration process was controlled by a skin thin layer of rejected materials. The ceramic water filters of both filtration modules have high removal efficiency of total suspended solids up to 100% and of turbidity up to 99.94%.

  6. Increasing the Reliability of the Work of Artificial Filtering Arrays for the Purification of Quarry Waste Water

    Science.gov (United States)

    Tyulenev, Maxim; Lesin, Yury; Litvin, Oleg; Maliukhina, Elena; Abay, Asmelash

    2017-11-01

    Features of geological structure of the Kuznetsk coal basin stipulate the application of a low-cost open technique of coal mining, which is more advantageous both from the economic standpoint, and by safety criteria of mining. However, open mining affects significantly the water resources of region. Intensive pollution of reservoirs and water courses, exhaustion of the underground water-bearing layers, violation of a hydrographic network, etc. be-long to the main disadvantages of an open technique of coal mining. Besides, the volume of the water coming into the mining producers exceeds signi-ficantly the needed quantity. According to the data of annual reports of ecology and natural resources department, 348.277 million m3 of water were ta-ken away during production of soft coal, brown coal and lignum fossil from waters of Kemerovo region in 2013 (mostly from underground water objects (96,5%) when draining of mine openings). At the same time, only 87.018 million m3 of water (25%) has been used within a year.

  7. Clay Ceramic Filter for Water Treatment

    Directory of Open Access Journals (Sweden)

    Zereffa Enyew Amare

    2017-05-01

    Full Text Available Ceramic water filters were prepared from different proportions of kaolin and soft wood and sintered at 900 °C, 950 °C, and 1000 °C. The flow rate, conductivity, pH of filtered water and removal efficiency (microbial, water hardness agent’s, nitrite and turbidity were analysed. The ceramic filter with 15 % saw dust, 80 % clay and 5 % grog that was fired at temperature of 950 °C or 1000 °C showed the best removal efficiency. Statistical ANOVA tests showed a significant difference between ceramic filters with various compositions in their removal efficiencies.

  8. Filters for water purification from radionuclides

    International Nuclear Information System (INIS)

    Mironov, V.V.; Khaydarov, R.R.; Khaydarov, R.A.; Gapurova, O.U.

    2006-01-01

    Full text: At present purification of waste water and drinking water from radionuclides, heavy metal ions, and organic contaminants is one of the most important problems. One of widely used methods for solving this problem is the ion exchange method based on using of different types of resins and fibroid sorbents. This paper deals with new chemically modified polyester fibroid filters having satisfactory adsorption characteristics. The process of the filter production includes their treatment by acrylonitrilic emulsion for improving mechanical characteristics. An advantage of the fibroid ion-exchange sorbents over resin is in their high sorption rate, effective regeneration and small value of pressure drop of the sorbent layer for purified water. The specific surface of the fibroid sorbents is (2 - 3). 10 4 m 2 / kg, i.e. about 10 2 times greater than that of the resin (10 2 m 2 / kg). Owing to that fact the rate of the sorption process on the developed fibroid sorbents is much greater than that on the resin. The developed cation- and anion-exchange filters can be used for removing metal ions (Zn, Ni, Cu, Sb, Co, Cd, Cr, etc.) and organic compounds (M- 32 P, M- 131 I, M- 99 Mo+ 99m Tc, etc.) from water. Capacity of the cation-exchange sorbents is 0.25 meq/g (Cu 2+ ) and that of the anion - exchange is 0.45 meq/g (Cr 6+ ). The cation- and anion-exchange filters are also selective for removing radionuclides 134 , 137 Cs, 90 Sr, 60 Co and 129 I in presence of Na + , K + , Ca 2+ , Mg 2+ , Cl - ions in water at concentrations up to 500 mg/L. New developed ion-exchange sorbents have been used in drinking water filters and mini-systems for removing organic and inorganic contaminants, in the equipment for waste water purification from oil products (at atomic power stations, car-washing stations, etc), from heavy metal ions (in electronic industry, match fabrics, leather processing plants etc). (author)

  9. Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

    Directory of Open Access Journals (Sweden)

    Bruderek Juliane

    2008-10-01

    Full Text Available Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Technology with a newly-introduced silver layer on the filtration membrane was compared to its preceding type without such a layer on 15 water outlets. We determined growth of Legionella, other pathogenic bacteria, and the total heterotrophic plate count in unfiltered water and filtered water samples after filter usage intervals of 1 through 4 weeks. Results A total of 299 water samples were tested. Twenty-nine of the 60 unfiltered water samples contained Legionella of various serogroups (baseline value. In contrast, all samples filtered by the original water filter and all but one of the water samples filtered by the modified filter type remained Legionella-free. No other pathogenic bacteria were detected in any filtered sample. The total plate count in water samples increased during use of both kinds of filters over time. However, for the first 7 days of use, there were significantly fewer water samples containing >100 CFU per mL when using the new filter device compared with the older filters or taps with no filter. No advantage was seen thereafter. Conclusion The use of this type of terminal water filter is an appropriate method to protect immunocompromised patients from water-borne pathogens such as Legionella.

  10. Potential for HEPA filter damage from water spray systems in filter plenums

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W. [Lawrence Livermore National Lab., CA (United States); Fretthold, J.K. [Rocky Flats Safe Sites of Colorado, Golden, CO (United States); Slawski, J.W. [Department of Energy, Germantown, MD (United States)

    1997-08-01

    The water spray systems in high efficiency particulate air (HEPA) filter plenums that are used in nearly all Department of Energy (DOE) facilities for protection against fire was designed under the assumption that the HEPA filters would not be damaged by the water sprays. The most likely scenario for filter damage involves filter plugging by the water spray, followed by the fan blowing out the filter medium. A number of controlled laboratory tests that were previously conducted in the late 1980s are reviewed in this paper to provide a technical basis for the potential HEPA filter damage by the water spray system in HEPA filter plenums. In addition to the laboratory tests, the scenario for BEPA filter damage during fires has also occurred in the field. A fire in a four-stage, BEPA filter plenum at Rocky Flats in 1980 caused the first three stages of BEPA filters to blow out of their housing and the fourth stage to severely bow. Details of this recently declassified fire are presented in this paper. Although these previous findings suggest serious potential problems exist with the current water spray system in filter plenums, additional studies are required to confirm unequivocally that DOE`s critical facilities are at risk. 22 refs., 15 figs.

  11. Filtered atmospheric venting of light water reactor containments

    International Nuclear Information System (INIS)

    Hedgran, A.; Ahlstroem, P.E.; Nilsson, L.; Persson, Aa.

    1982-11-01

    The aim of filtered venting is to improve the function of the reactor containment in connection with very severe accidents. By equipping the containment with a safety valve for pressure relief and allowing the released gases to pass through an effective filter, it should be possible to achieve a considerable protective effect. The work has involved detailed studies of the core meltdown sequence, how the molten core material runs out of the reactor vessel, what effect it has on concrete and other structures and how final cooling of the molten core material takes place. On the basis of previous Swedish studies, the project has chosen to study a filter concept that consists of a gravel bed of large volume. This filter plant shall not only retain the radioactive particles that escape from the containment through the vent line, but shall also condense the accompanying steam. After the government decided in 1981 that Barsebaeck was to be equipped with filtered venting and issued specifications regarding its performance, the project aimed at obtaining results that could be used to design and verify a plant for filtered venting at the Barsebaeck nuclear power station. As far as the other Swedish nuclear power plants at Oskarshamn, Ringhals and Forsmark are concerned, the results are only applicable to a limited extent. Additional studies are required for these nuclear power plants before the value of filtered venting can be assessed. Based on the results of experiments and analyses, the project has made a safety analysis with Barsebaeck as a reference plant in order to study how the introduction of filtered venting affects the safety level at a station. In summary, the venting function appears to entail a not insignificant reduction of risks for boiling water reactors of the Barsebaeck type. For a number of types of such very severe core accident cases, the filter design studied ensures a substantial reduction of the releases. However it has not been possible within the

  12. Prokaryotic communities in drinking water biofilters using alternative filter medium

    DEFF Research Database (Denmark)

    Breda, Inês Lousinha Ribeiro; Roslev, Peter; Ramsay, Loren

    in an alternative filter medium during the start-up of manganese removal. Filter media properties were measured using gravimetric methods and a photometric particle analyzer. Physical, chemical and microbial analyses were used to follow the manganese ripening. Microbial analyses of both inlet water and filter...

  13. Avoiding the Use of Exhausted Drinking Water Filters: A Filter-Clock Based on Rusting Iron

    Directory of Open Access Journals (Sweden)

    Arnaud Igor Ndé-Tchoupé

    2018-05-01

    Full Text Available Efficient but affordable water treatment technologies are currently sought to solve the prevalent shortage of safe drinking water. Adsorption-based technologies are in the front-line of these efforts. Upon proper design, universally applied materials (e.g., activated carbons, bone chars, metal oxides are able to quantitatively remove inorganic and organic pollutants as well as pathogens from water. Each water filter has a defined removal capacity and must be replaced when this capacity is exhausted. Operational experience has shown that it may be difficult to convince some low-skilled users to buy new filters after a predicted service life. This communication describes the quest to develop a filter-clock to encourage all users to change their filters after the designed service life. A brief discussion on such a filter-clock based on rusting of metallic iron (Fe0 is presented. Integrating such filter-clocks in the design of water filters is regarded as essential for safeguarding public health.

  14. Dataset on the spent filter backwash water treatment by sedimentation, coagulation and ultra filtration

    OpenAIRE

    Mokhtar Mahdavi; Afshin Ebrahimi; Hossein Azarpira; Hamid Reza Tashauoei; Amir Hossein Mahvi

    2017-01-01

    During operation of most water treatment plants, spent filter backwash water (SFBW) is generated, which accounts about 2â10% of the total plant production. By increasing world population and water shortage in many countries, SFBW can be used as a permanent water source until the water treatment plant is working. This data article reports the practical method being used for water reuse from SFBW through different method including pre-sedimentation, coagulation and flocculation, second clarific...

  15. Hydraulic modeling of clay ceramic water filters for point-of-use water treatment.

    Science.gov (United States)

    Schweitzer, Ryan W; Cunningham, Jeffrey A; Mihelcic, James R

    2013-01-02

    The acceptability of ceramic filters for point-of-use water treatment depends not only on the quality of the filtered water, but also on the quantity of water the filters can produce. This paper presents two mathematical models for the hydraulic performance of ceramic water filters under typical usage. A model is developed for two common filter geometries: paraboloid- and frustum-shaped. Both models are calibrated and evaluated by comparison to experimental data. The hydraulic models are able to predict the following parameters as functions of time: water level in the filter (h), instantaneous volumetric flow rate of filtrate (Q), and cumulative volume of water produced (V). The models' utility is demonstrated by applying them to estimate how the volume of water produced depends on factors such as the filter shape and the frequency of filling. Both models predict that the volume of water produced can be increased by about 45% if users refill the filter three times per day versus only once per day. Also, the models predict that filter geometry affects the volume of water produced: for two filters with equal volume, equal wall thickness, and equal hydraulic conductivity, a filter that is tall and thin will produce as much as 25% more water than one which is shallow and wide. We suggest that the models can be used as tools to help optimize filter performance.

  16. Removal method of radium in mine water by filter sand

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Naganuma, Masaki

    2003-01-01

    Trace radium is contained in mine water from the old mine road in Ningyo-Toge Environmental Engineering Center, JNC. We observed that filter sand with hydrated manganese oxide adsorbed radium in the mine water safely for long time. The removal method of radium by filter sand cladding with hydrated manganese oxide was studied. The results showed that radium was removed continuously and last for a long time from mine water with sodium hypochlorite solution by passing through the filter sand cladding with hydrated manganese. Only sodium hypochlorite solution was used. When excess of it was added, residue chlorine was used as chlorine disinfection. Filter sand cladding with hydrated manganese on the market can remove radium in the mine water. The removal efficiency of radium is the same as the radium coprecipitation method added with barium chloride. The cost is much lower than the ordinary methods. Amount of waste decreased to about 1/20 of the coprecipitation method. (S.Y.)

  17. Conductive Cotton Filters for Affordable and Efficient Water Purification

    Directory of Open Access Journals (Sweden)

    Fang Li

    2017-09-01

    Full Text Available It is highly desirable to develop affordable, energy-saving, and highly-effective technologies to alleviate the current water crisis. In this work, we reported a low-cost electrochemical filtration device composing of a conductive cotton filter anode and a Ti foil cathode. The device was operated by gravity feed. The conductive cotton filter anodes were fabricated by a facile dying method to incorporate carbon nanotubes (CNTs as fillers. The CNTs could serve as adsorbents for pollutants adsorption, as electrocatalysts for pollutants electrooxidation, and as conductive additives to render the cotton filters highly conductive. Cellulose-based cotton could serve as low-cost support to ‘host’ these CNTs. Upon application of external potential, the developed filtration device could not only achieve physically adsorption of organic compounds, but also chemically oxide these compounds on site. Three model organic compounds were employed to evaluate the oxidative capability of the device, i.e., ferrocyanide (a model single-electron-transfer electron donor, methyl orange (MO, a common recalcitrant azo-dye found in aqueous environments, and antibiotic tetracycline (TC, a common antibiotic released from the wastewater treatment plants. The devices exhibited a maximum electrooxidation flux of 0.37 mol/h/m2 for 5.0 mmol/L ferrocyanide, of 0.26 mol/h/m2 for 0.06 mmol/L MO, and of 0.9 mol/h/m2 for 0.2 mmol/L TC under given experimental conditions. The effects of several key operational parameters (e.g., total cell potential, CNT amount, and compound concentration on the device performance were also studied. This study could shed some light on the good design of effective and affordable water purification devices for point-of-use applications.

  18. Granular filters for water treatment: heterogeneity and diagnostic tools

    DEFF Research Database (Denmark)

    Lopato, Laure Rose

    the last barrier against disinfection resistant protozoan pathogens and this has led to increased regulation of the filtration process. To be able to produce high-quality filtrate in a constant and reliable manner while meeting stricter drinking water guideline values, it is important to be able......Rapid granular filters are the most commonly used filters in drinking water treatment plants and are the focus of this PhD study. They are usually constructed with sand, anthracite, activated carbon, garnet sand, and ilmenite and have filtration rates ranging from 3 to 15 m/h. Filters are often...... options prescribed. The diagnostic tools are then used again to verify the efficiency of the solution applied. If the problem is not solved the whole process starts again. These tools are of significant interest for the development of the Water Safety Plans recommended by WHO to monitor filters...

  19. Microbiological effectiveness of locally produced ceramic filters for drinking water treatment in Cambodia.

    Science.gov (United States)

    Brown, Joe; Sobsey, Mark D

    2010-03-01

    Low-cost options for the treatment of drinking water at the household level are being explored by the Cambodian government and non-governmental organizations (NGOs) working in Cambodia, where many lack access to improved drinking water sources and diarrhoeal diseases are the most prevalent cause of death in children under 5 years of age. The ceramic water purifier (CWP), a locally produced, low-cost ceramic filter, is now being implemented by several NGOs, and an estimated 100,000+households in the country now use them for drinking water treatment. Two candidate filters were tested for the reduction of bacterial and viral surrogates for waterborne pathogens using representative Cambodian drinking water sources (rainwater and surface water) spiked with Escherichia coli and bacteriophage MS2. Results indicate that filters were capable of reducing key microbes in the laboratory with mean reductions of E. coli of approximately 99% and mean reduction of bacteriophages of 90-99% over >600 litres throughput. Increased effectiveness was not observed in filters with an AgNO3 amendment. At under US$10 per filter, locally produced ceramic filters may be a promising option for drinking water treatment and safe storage at the household level.

  20. A Simple Slow-Sand Filter for Drinking Water Purification

    Directory of Open Access Journals (Sweden)

    K. O. Yusuf

    2017-04-01

    Full Text Available Water-borne diseases are commonly encountered when pathogen-contaminated water is consumed. In rural areas, water is usually obtained from ponds, open shallow wells, streams and rain water during rainy season. Rain water is often contaminated by pathogens due to unhygienic of physical and chemical conditions of the roofs thereby making it unsafe for consumption. A simple slow sand filter mechanism was designed and fabricated for purification of water in rural areas where electricity is not available to power water purification devices. Rain water samples were collected from aluminum roof, galvanized roof and thatched roof. The waters samples were allowed to flow through the slow sand filter. The values of turbidity, total dissolved solids, calcium, nitrite, faecal coliform and total coliform from unfiltered water through thatched roof were 0.92 NTU, 27.23 mg/l, 6 mg/l, 0.16 mg/l, 5cfu/100ml and 6.0 cfu/100ml, respectively while the corresponding values for slow sand filter from thatched roof were 0.01 NTU, 0.23 mg/l, 2.5 mg/l, 0.1 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values of turbidity, total dissolved solid, nitrite, calcium, faecal coliform and total coliform from unfiltered water for aluminum roof were 0.82 NTU, 23.68 mg/l, 2.70 mg/l, 1.0 mg/l, 4 cfu/100ml and 4cfu/100ml, respectively while the corresponding values for slow sand filter were 0.01 NTU, 0.16 mg/l, 0.57 mg/l, 0.2 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values obtained for galvanized roof were also satisfactory. The slow sand filter is recommended for used in rural areas for water purification to prevent risk of water-borne diseases.

  1. Application of a Low Cost Ceramic Filter for Recycling Sand Filter Backwash Water

    Directory of Open Access Journals (Sweden)

    Md Shafiquzzaman

    2018-02-01

    Full Text Available The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW. The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum followed by continuous filtration usinga low cost ceramic filter at different trans-membrane pressures (TMPs. Jar test results showed that 20 mg/L of alum is the optimum dose for maximum removal of turbidity, Fe, and Mn from SFBW. The filter can be operated at a TMP between 0.6 and 3 kPa as well as a corresponding flux of 480–2000 L/m2/d without any flux declination. Significant removal, up to 99%, was observed forturbidity, iron (Fe, and manganese (Mn. The flux started to decline at 4.5 kPa TMP (corresponding flux 3280 L/m2/d, thus indicated fouling of the filter. The complete pore blocking model was found as the most appropriate model to explain the insight mechanism of flux decline. The optimum operating pressure and the permeate flux were found to be 3 kPa and 2000 L/m2/d, respectively. Treated SFBW by a low cost ceramic filter was found to be suitable to recycle back to the water treatment plant. The ceramic filtration process would be a low cost and efficient option to recycle the SFBW.

  2. Copper deficiency can limit nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt; Nielsen, Peter Borch; Boe-Hansen, Rasmus

    2016-01-01

    Incomplete nitrification in biological filters during drinking water treatment is problematic, as it compromises drinking water quality. Nitrification problems can be caused by a lack of nutrients for the nitrifying microorganisms. Since copper is an important element in one of the essential...... enzymes in nitrification, we investigated the effect of copper dosing on nitrification in different biological rapid sand filters treating groundwater. A lab-scale column assay with filter material from a water works demonstrated that addition of a trace metal mixture, including copper, increased ammonium...... to the bulk phase. Overall, copper dosing to poorly performing biological rapid sand filters increased ammonium removal rates significantly, achieving effluent concentrations of below 0.01 mg NH4-N L-1, and had a long-term effect on nitrification performance....

  3. Modeling Flow Rate to Estimate Hydraulic Conductivity in a Parabolic Ceramic Water Filter

    Directory of Open Access Journals (Sweden)

    Ileana Wald

    2012-01-01

    Full Text Available In this project we model volumetric flow rate through a parabolic ceramic water filter (CWF to determine how quickly it can process water while still improving its quality. The volumetric flow rate is dependent upon the pore size of the filter, the surface area, and the height of water in the filter (hydraulic head. We derive differential equations governing this flow from the conservation of mass principle and Darcy's Law and find the flow rate with respect to time. We then use methods of calculus to find optimal specifications for the filter. This work is related to the research conducted in Dr. James R. Mihelcic's Civil and Environmental Engineering Lab at USF.

  4. Turbidity and microbes removal from water using an electrochemical filter

    International Nuclear Information System (INIS)

    Venkateswaran, G.; Gokhale, B.K.; Belapurkar, A.D.; Kumbhar, A.G.; Balaji, V.

    2004-01-01

    An in-house designed and fabricated Electrochemical fibrous graphite filter (ECF) was used to remove turbidity and microbes. The filter was found to be effective in removing sub micron size indium turbidity from RAPS-1 moderator water, iron turbidity from Active Process Cooling Water (APCW) of Kaiga Generating Station and microbial reduction from process cooling water RAPS-2. Unlike conventional turbidity removal by addition of coagulants and biocide chemical additions for purification, ECF is a clean way to remove the turbidity without contaminating the system and is best suited for close loop systems

  5. Ranking filter methods for concentrating pathogens in lake water

    Science.gov (United States)

    Accurately comparing filtration methods for concentrating waterborne pathogens is difficult because of two important water matrix effects on recovery measurements, the effect on PCR quantification and the effect on filter performance. Regarding the first effect, we show how to create a control water...

  6. Purification of power plant waters with high gradient magnetic filters

    International Nuclear Information System (INIS)

    Rosenberg, R.

    1993-04-01

    This is a report of a literature survey. Magnetic high gradient filtration is suitable for separations in difficult surroundings because it can be used in high pressure and temperature, the filtration can be automated and the filter does not contain components which have to be replaced. Magnetic separators for purification of power plant waters have been manufactured commercially for a long time, but they have not always worked satisfactorily especially when separating small particles. The corrosion products in power plant waters are usually ferrimagnetic or paramagnetic and are well suited for magnetic separation. The particle sizes varies considerable but at least in nuclear power plants they are mostly in the range 0.1-30 μ, some even smaller. According to different publications most 60 Co is in particles, while other publications indicate that more than 70 % is in solution. Similarly the data on the purification efficiency of 60 Co varies significantly. Even small magnetic fields are sufficient to separate large ferrimagnetic particles, but the separation of small and paramagnetic particles requires a field more than 20 kT and the high gradient. Presently available commercial separators are so efficient that its seems not to be economically worthwhile to develop them further to improve the filtration efficiency for small particles. Instead it might be worthwhile to investigate methods to increase the particle size by water chemistry methods. (Au). (25 refs., 2 figs.)

  7. Water flow exchange characteristics in coarse granular filter media

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Pugliese, Lorenzo; Poulsen, Tjalfe

    2013-01-01

    Elution of inhibitory metabolites is a key parameter controlling the efficiency of air cleaning bio- and biotrickling filters. To the authors knowledge no studies have yet considered the relationship between specific surface area related elution velocity and physical media characteristics, which...... in this study are performed at a concurrent airflow of 0.3 m s−1, water irrigation rates of 1–21 cm h−1 in materials with particle diameters ranging from 2 to 14 mm to represent media and operation conditions relevant for low flow biotrickling filter design. Specific surface area related elution velocity...... distribution was closely related to the filter water content, water irrigation rate, media specific surface area and particle size distribution. A predictive model linking the specific surface area related elution velocity distribution to irrigation rate, specific surface area and particle size distribution...

  8. Arsenic removal for ceramic water filters

    Directory of Open Access Journals (Sweden)

    Mishant Kumar

    2013-02-01

    Full Text Available Arsenic in drinking water is a hazard to human health and is a known carcinogen (Mass 1992. Resource Development International – Cambodia (RDIC has researched, developed, and manufactured simple ceramic water fi lters (CWF which have proved to be extremely effective in removing pathogens from water. These fi lters however, do not remove arsenic from water, which exists in the source water at levels above the World Health Organisation (WHO guideline of 10μg/L. The aims of this literature based study were to investigate conventional and non-conventional arsenic removal processes, and to discuss the options for applying an arsenic removal technology to the CWFs produced by RDIC. It was found that conventional arsenic removal technologies are diffi cult to implement in the context of household water treatment in a developing country. This study suggested that non-conventional arsenic removal technologies shall be more effective and that field studies must be undertaken to verify the success of such methods.

  9. Experimental investigation of an optical water filter for Photovoltaic/Thermal conversion module

    International Nuclear Information System (INIS)

    Al-Shohani, Wisam A.M.; Sabouri, Aydin; Al-Dadah, Raya; Mahmoud, Saad; Butt, Haider

    2016-01-01

    Highlights: • New design of Photovoltaic/Thermal system is proposed. • Using the optical water layer as a spectrum splitter is tested experimentally. • Optical rig is developed to study the optical performance of water layer. • Energy conversion under different water layer thicknesses is determined. - Abstract: This paper presents an experimental investigation of a novel optical water filter used for Photovoltaic/Thermal and Concentrating Photovoltaic/Thermal modules. A water layer is used as a spectrum splitter of solar radiation placed above the photovoltaic cells and as a thermal working fluid simultaneously. The water layer absorbs the ultraviolet and part of infrared, which are not used by the photovoltaic, but transmits the visible and some of infrared to the solar cell surface which are used by the photovoltaic. In this work, the transmittance of the optical water filter was measured for different water thicknesses (1, 2, 3, 4, and 5 cm) and radiation wavelength ranging from 0.35 to 1 μm. Results show that there is a significant effect of the water layer thickness on the transmittance of the spectra where the transmittance decreases as the water layer increases. Moreover, energy conversion rate of photovoltaic with the optical water filter at different water layer thicknesses has been determined.

  10. Application of Self Cleaning Rapid Sand Filter in Water Treatment

    Directory of Open Access Journals (Sweden)

    Ali Reza Rahmani

    2005-08-01

    Full Text Available Rapid sand filter is one of the most important units in the water treatment plants. It has some difficulties in operation such as backwashing. For the solving of this problem a rapid sand filter has designed and built with the self-cleaning backwashing system. This system consist of 3 main constituents; one galvanized siphon and two galvanized steel tanks. One of them is used for filtration and the other used for the storage of filtrated water in elevation for backwashing the system. Water enter from upside of the filter through the inlet pipe, and collected from the under drainage pipe. Then filter water conduct to the storage tank and exit from outlet pipe. In the beginning, the head loss was low, but because of bed clogging by suspended solids, it increases gradually to the designed head loss (1.2m. Then the system is outed of the service automatically and the backwash is began. The main data for the design of system selected from the hydraulic rules of siphons and rapid sand filter criteria. After essential calculations it was constructed and was started operation. For the hydraulic studies a known volume of storage tank was selected and the time needed for the fill (in filtration stage and empty (in backwash stage of water volume with volumetric method were measured. In hydraulic studies the filter surface rate (SOR was selected about 5-7.5m3/m2/hr (1.39-2.08 lit/sec and the flow of water in siphon, during the backwashing was measured 8.7 lit/sec. It can be seen that the siphon passes 4-6 times the inlet raw water thus a negative pressure will created in the siphon which causes the water above the sand bed to be discharged automatically and rinse water from elevated tank flow under the sand bed and back wash it. So according to this study self cleaning rapid sand filter is very useful for water filtration, especially in small population community. The construction of system is rapid, simple and economic.

  11. Manufacturing a low-cost ceramic water filter and filter system for the elimination of common pathogenic bacteria

    Science.gov (United States)

    Simonis, J. J.; Basson, A. K.

    Africa is one of the most water-scarce continents in the world but it is the lack of potable water which results in diarrhoea being the leading cause of death amongst children under the age of five in Africa (696 million children under 5 years old in Africa contract diarrhoea resulting in 2000 deaths per day: WHO and UNICEF, 2009). Most potable water treatment methods use bulk water treatment not suitable or available to the majority of rural poor in Sub-Saharan Africa. One simple but effective way of making sure that water is of good quality is by purifying it by means of a household ceramic water filter. The making and supply of water filters suitable for the removal of suspended solids, pathogenic bacteria and other toxins from drinking water is therefore critical. A micro-porous ceramic water filter with micron-sized pores was developed using the traditional slip casting process. This locally produced filter has the advantage of making use of less raw materials, cost, labour, energy and expertise and being more effective and efficient than other low cost produced filters. The filter is fitted with a silicone tube inserted into a collapsible bag that acts as container and protection for the filter. Enhanced flow is obtained through this filter system. The product was tested using water inoculated with high concentrations of different bacterial cultures as well as with locally polluted stream water. The filter is highly effective (log10 > 4 with 99.99% reduction efficiency) in providing protection from bacteria and suspended solids found in natural water. With correct cleaning and basic maintenance this filter technology can effectively provide drinking water to rural families affected by polluted surface water sources. This is an African solution for the more than 340 million people in Africa without access to clean drinking water (WHO and UNICEF, 2008).

  12. Assessment of crushed-recycled glass as filter media for drinking water treatment

    International Nuclear Information System (INIS)

    Rutledge, S.O.; Fahie, C.; Gagnon, G.A.

    2002-01-01

    The objective of this project was to evaluate the performance of a pressure filter utilizing crushed glass as the filter media. The performance of the crushed glass filter was compared to that of a sand filter. The research was conducted in Orangedale, Nova Scotia, which is a small community of with a population of approximately 500. Orangedale is located on the south shore of Bras d'Or Lakes and feeds into Miller Pond, which serves as the source the of drinking water. The Orangedale treatment plant produces an average daily flow of 35 m3/d (6.4-gpm). The treatment plant consists of coagulation (sodium aluminate and polyaluminum chloride), flocculation, dissolved air flotation (DAF), disinfection with sodium hypochlorite and dual-media filtration with anthracite and sand. In general, the particle removal capabilities of the crushed glass filter were slightly poorer than that of a sand filter, as quantified in a field application in the community of Orangedale, Nova Scotia. It was found that the crushed glass used in this project had a higher angularity and slightly higher uniformity coefficient. During initial start-up the performance of the crushed glass filter was more variable and appeared to improve as the glass began to wear. After six-months of use the crushed glass filter was able to produce a very consistent filter effluent that was only slightly greater than the silica sand filter. After six-months of use, the sand filter achieved a 1.6 log-removal of particles with diameters greater than 2 μm; whereas the crushed glass filter achieved a 1.4 log removal for the similar particle size range. The observed removal performance was particularly encouraging given that the sand used had properties that were consistent with the standards set by the American Water Works Association. The crushed glass filter media was initially sieved and washed, but had no other pre-treatment preparation. Thus the application of crushed glass shows considerable promise as filter

  13. Treatment of residual waters of slaughterhouses with filters

    International Nuclear Information System (INIS)

    Ortiz A, Jesus Mario

    1995-01-01

    For studying the anaerobic treatment of the residual waters coming from a slaughterhouse of bovine livestock, they were used a system of two filters in series and a third unique filter as witness. With values average of load organic volumetric and time of retention of 1.6 kg/(m 3 d) and 26 hours respectively, the efficiencies of removal of total DQO were similar in the unique filter and in the system in series, of the order of 64% on the average. Likewise, the retention and accumulation of biological solids in the channel were shown as the main road of removal of the DQO. The differentiation of the process achieved with the two filters in series allowed establishing that most of the accumulation happened in the primary filter, as long as the fundamental of the bioconversion in methane took place in the secondary filter of the system in series. The first relative level of methanegenization obtained could be explained by the limitations to the activity of the methanogenic biomass imposed by the low temperatures, although it could not discard a probable inhibition for the hydrolysis products of the accumulated fats

  14. The Military Efficacy of Individual Water Purification Filters.

    Science.gov (United States)

    1990-12-01

    criteria. ’t *.;as a.Lso serv ea that the KPF units grew opportunistic Pseudomonas sp . on the oroduct water side of the filters, which could have a...small pathogenic protozoan cysts such as Cryptospor-dium parvum, Giardia lamblia, and Entamoeba coli, from water over the effective use life of the...of heterotrophic bacteria such as Pseudoronas sP , Flavobacterium Sp , and other potentially harmfui organisms inside of the units. Enteric viruses are

  15. Modeling the sustainability of a ceramic water filter intervention.

    Science.gov (United States)

    Mellor, Jonathan; Abebe, Lydia; Ehdaie, Beeta; Dillingham, Rebecca; Smith, James

    2014-02-01

    Ceramic water filters (CWFs) are a point-of-use water treatment technology that has shown promise in preventing early childhood diarrhea (ECD) in resource-limited settings. Despite this promise, some researchers have questioned their ability to reduce ECD incidences over the long term since most effectiveness trials conducted to date are less than one year in duration limiting their ability to assess long-term sustainability factors. Most trials also suffer from lack of blinding making them potentially biased. This study uses an agent-based model (ABM) to explore factors related to the long-term sustainability of CWFs in preventing ECD and was based on a three year longitudinal field study. Factors such as filter user compliance, microbial removal effectiveness, filter cleaning and compliance declines were explored. Modeled results indicate that broadly defined human behaviors like compliance and declining microbial effectiveness due to improper maintenance are primary drivers of the outcome metrics of household drinking water quality and ECD rates. The model predicts that a ceramic filter intervention can reduce ECD incidence amongst under two year old children by 41.3%. However, after three years, the average filter is almost entirely ineffective at reducing ECD incidence due to declining filter microbial removal effectiveness resulting from improper maintenance. The model predicts very low ECD rates are possible if compliance rates are 80-90%, filter log reduction efficiency is 3 or greater and there are minimal long-term compliance declines. Cleaning filters at least once every 4 months makes it more likely to achieve very low ECD rates as does the availability of replacement filters for purchase. These results help to understand the heterogeneity seen in previous intervention-control trials and reemphasize the need for researchers to accurately measure confounding variables and ensure that field trials are at least 2-3 years in duration. In summary, the CWF

  16. Comammox Nitrospira are key nitrifiers in diverse groundwater-fed drinking water filters

    DEFF Research Database (Denmark)

    Fowler, Jane; Palomo, Alejandro; Smets, Barth F.

    Nitrification is a dominant process in groundwater-fed rapid sand filters (RSFs) used for drinking water purification. Near complete removal of ammonium and nitrite is required in the EU and Denmark due to strict regulatory limits that enable high water stability in the distribution system. RSFs...... this work provides a new assay for the simultaneous detection of clade A and B comammox Nitrospira and expands our current knowledge of the diversity of comammox Nitrospira, while attempting to explain the success of comammox Nitrospira in these groundwater-fed filters....

  17. UV Fluorescence Photography of Works of Art : Replacing the Traditional UV Cut Filters with Interference Filters

    Directory of Open Access Journals (Sweden)

    Luís BRAVO PEREIRA

    2010-09-01

    Full Text Available For many years filters like the Kodak Wratten E series, or the equivalent Schneider B+W 415, were used as standard UV cut filters, necessary to obtain good quality on UV Fluorescence photography. The only problem with the use of these filters is that, when they receive the UV radiation that they should remove, they present themselves an internal fluorescence as side effect, that usually reduce contrast and quality on the final image. This article presents the results of our experiences on using some innovative filters, that appeared available on the market in recent years, projected to adsorb UV radiation even more efficiently than with the mentioned above pigment based standard filters: the interference filters for UV rejection (and, usually, for IR rejection too manufactured using interference layers, that present better results than the pigment based filters. The only problem with interference filters type is that they are sensitive to the rays direction and, because of that, they are not adequate to wide-angle lenses. The internal fluorescence for three filters: the B+W 415 UV cut (equivalent to the Kodak Wratten 2E, pigment based, the B+W 486 UV IR cut (an interference type filter, used frequently on digital cameras to remove IR or UV and the Baader UVIR rejection filter (two versions of this interference filter were used had been tested and compared. The final quality of the UV fluorescence images seems to be of a superior quality when compared to the images obtained with classic filters.

  18. Origin of bank filtered groundwater resources covering the drinking water demand of Budapest, Hungary

    International Nuclear Information System (INIS)

    Forizs, I.; Deak, J.

    1998-01-01

    The ratio of Danube water/infiltrated precipitation has been determined using stable oxygen isotope data on four parts of the protection area of the bank filtered water works supplying drinking water for Budapest, Hungary. These ratios comparing to those calculated by hydraulic modeling rarely match each other. The Danube water transit time calculated fro few wells by isotopic data are usually shorter than those determined by hydraulic modeling. The relation between the δ 18 O values and the nitrate chloride and sulfate pollutants shows that the source of the pollutants is on the island area (sewage water, agricultural activity and salt used for de-icing asphalt roads). (author)

  19. Durable superhydrophobic and superoleophilic filter paper for oil–water separation prepared by a colloidal deposition method

    International Nuclear Information System (INIS)

    Du, Chuan; Wang, Jiadao; Chen, Zhifu; Chen, Darong

    2014-01-01

    Graphical abstract: - Highlights: • A method for fabricating durable superhydrophobic filter paper was developed. • Oil–water separation efficiency exceeds 99% using the as-prepared filter paper. • The as-prepared filter paper has good recyclability and durability. • The method is easy, low cost and can be industrialized. - Abstract: A method for manufacturing durable superhydrophobic and superoleophilic filter paper for oil–water separation was developed via colloidal deposition. A porous film composed of PTFE nanoparticles was formed on filter paper, which was superhydrophobic with a water contact angle of 155.5° and superoleophilic with an oil contact angle of 0°. The obtained filter paper could separate a series of oil–water mixtures effectively with high separation efficiencies over 99%. Besides, the as-prepared filter paper kept stable superhydrophobicity and high separation efficiency even after 30 cycle times and could also work well under harsh environmental conditions like strong acidic or alkaline solutions, high temperature and ultraviolet irradiation. Compared with other approaches for fabricating oil–water materials, this approach is able to fabricate full-scale durable and practical oil–water materials easily and economically. The as-prepared filter paper is a promising candidate for oil–water separation

  20. Compatibility between Hydraulic and Mechanical Properties of Ceramic Water Filters

    Directory of Open Access Journals (Sweden)

    Riyadh Z. Al Zubaidy

    2017-05-01

    Full Text Available In this paper, ceramic water filters were produced by using ten mixtures of different ratios of red clay and sawdust under different production conditions. The physical properties of these filters were tested. The production conditions include five press pressures ranged from 10 to 50MPa and a firing schedule having three different final temperatures of 1000, 1070, and 1100˚C. The tests results of the physical properties were used to obtain best compatibility between the hydraulic and the mechanical properties of these filters. Results showed that as the press pressure and the firing temperature are increased, the bulk density and the compressive and bending strengths of the produced filters are increased, while, the porosity and absorption are decreased. As the sawdust content is increased the bulk density and the compressive and bending strengths are decreased, while, the porosity and absorption are increased. High hydraulic conductivity is obtained at a firing temperature of 1070˚C when the sawdust content is less than 10%. Otherwise, it is increased as sawdust content and the firing temperature are increased. Filters made of mixture 92.5% red clay and 7.5% sawdust formed . under a press pressure of 20MPa and a firing temperature of 1070˚C gave the best compatibility between hydraulic and mechanical properties. In this case, the hydraulic conductivity was 50mm/day, the compressive strength was 14MPa, and the bending strength was 10.8MPa.

  1. Quantifying the Water Footprint of Manufactured Products: A Case Study of Pitcher Water Filters

    Directory of Open Access Journals (Sweden)

    Ashley Barker

    2012-01-01

    Full Text Available Fresh water is a finite resource that is critically needed bysociety for a variety of purposes. The demand for freshwater will grow as the world population and global livingstandard increase, and fresh water shortages will becomemore commonplace. This will put significant stress onsociety. It has been argued that fresh water may becomethe next oil, and efforts have to be made to better manageits fresh water consumption by agricultural and domesticusers. Industry also uses large amounts. Surprisingly, onlyrecently is serious attention being directed toward waterrelatedissues. This effort to quantify the water footprint ofa manufactured product represents one of the first initiativesto characterize the role of water in a discrete good.This study employed a life cycle assessment methodologyto determine the water footprint of a pitcher water filter.This particular product was selected because many waterintensivematerials and processes are needed to produceits major components: for example, agricultural processesused to produce activated carbon and petrochemicalprocesses used to produce the polypropylene casing. Inaddition, a large amount of water is consumed during theproduct’s use phase. Water data was obtained from theEcoinvent 2.1 database and categorized as either beingassociated with blue or green water.The blue water footprint (surface water consumption forthe pitcher water filter was 76 gallons per filter: 10 gallonsconsumed for materials extraction, 15 gallons for themanufacturing stage, and 50 gallons during the use phase.The green water footprint (precipitation was associatedwith the cultivation of the coconut tree; activated carbonis obtained from the coconut shells. The green waterfootprint was calculated to be 164 gallons per filter.The overall water footprint was 240 gallons per filter;the filter footprint is heavily dominated by green water(68% rather than blue water (32%. Future studies mayinvestigate how the production and

  2. The filtering of raw water with partition system in pool row water for the process

    International Nuclear Information System (INIS)

    Harahap, Sentot Alibasya; Djunaidi

    2003-01-01

    The purpose of filtering raw water in the pool is decreasing soluble dirty in the water from Puspiptek PAM also the dirty from the environments. The monitoring of raw water since 1998 that the raw water is not so good in the quality. This partition system use tree type of screen a.i. the opened 10 mm, Mesh 60 and Mesh 100. The down position use a plat with 400 mm higher from the floor of the pool that given support frame from the L profile and strip plate by stainless steel (SS-304), use for deposited the impurities. The filter capability from the monitoring that the filtering result is a good quality, the TDS drop (Total Dissolved Solvent) is 2,5 gram/liter and the water filtering static type is (4 - 8,5) gram/liter

  3. Filters for water purification from oil products and radionuclides

    International Nuclear Information System (INIS)

    Khaydarov, R.R.; Khaydarov, R.A.; Gapurova, O.U.; Malikov, Sh.

    2006-01-01

    Full text: Purification of waste water and drinking water from radionuclides, heavy metal ions, and organic contaminants is one of the most important problems at present day. One of widely used methods for solving this problem is the ionic exchange method based on using different types of resins and fibroid sorbents. The paper deals with new chemically modified polyester fibroid filters having satisfactory adsorption characteristics. The process of the filter production includes their treatment by acrylo nitrilic emulsion for improving mechanical characteristics. An advantage of the fibroid ion-exchange sorbents over resin is in high rate of a sorption process, effective regeneration and small value of pressure drop of the sorbent layer for purified water. The specific surface of the fibroid sorbents is (2 - 3). 10'4 m 2 / kg, i.e. about 102 times greater than that of the resin (10 2 m 2 / kg). Owing to that fact the rate of the sorption process on the developed fibroid sorbents is much greater than that on the resin. The developed cation- and anion-exchange filters can be used for removing metal ions (Zn, Ni, Cu, Sb, Co, Cd, Cr, etc.) and organic compounds (M- P 32, M- I 131, M-Mo 99 mTc+99, etc.) from water. Capacity of the cation-exchange sorbents is 0.25 meq/g (Cu 2 +) and that of the anion - exchange is 0.45 meq/g (Cr 6 +). The cation- and anion-exchange filters are also selective for removing radionuclides Cs 134,137, Sr 90, Co 60 and I 129 in presence of Na + , K + , Ca 2 +, Mg 2 +, Cl - ions in water at concentrations up to 500 mg/L. New developed ionic-exchange sorbents have been used in drinking water filters and mini-systems for removing organic and inorganic contaminants, in the equipment for waste water purification from oil products (at atomic power stations, car-washing stations, etc), from heavy metal ions (in electronic industry, match fabrics, leather processing plants etc)

  4. Replicating the microbial community and water quality performance of full-scale slow sand filters in laboratory-scale filters.

    Science.gov (United States)

    Haig, Sarah-Jane; Quince, Christopher; Davies, Robert L; Dorea, Caetano C; Collins, Gavin

    2014-09-15

    Previous laboratory-scale studies to characterise the functional microbial ecology of slow sand filters have suffered from methodological limitations that could compromise their relevance to full-scale systems. Therefore, to ascertain if laboratory-scale slow sand filters (L-SSFs) can replicate the microbial community and water quality production of industrially operated full-scale slow sand filters (I-SSFs), eight cylindrical L-SSFs were constructed and were used to treat water from the same source as the I-SSFs. Half of the L-SSFs sand beds were composed of sterilized sand (sterile) from the industrial filters and the other half with sand taken directly from the same industrial filter (non-sterile). All filters were operated for 10 weeks, with the microbial community and water quality parameters sampled and analysed weekly. To characterize the microbial community phyla-specific qPCR assays and 454 pyrosequencing of the 16S rRNA gene were used in conjunction with an array of statistical techniques. The results demonstrate that it is possible to mimic both the water quality production and the structure of the microbial community of full-scale filters in the laboratory - at all levels of taxonomic classification except OTU - thus allowing comparison of LSSF experiments with full-scale units. Further, it was found that the sand type composing the filter bed (non-sterile or sterile), the water quality produced, the age of the filters and the depth of sand samples were all significant factors in explaining observed differences in the structure of the microbial consortia. This study is the first to the authors' knowledge that demonstrates that scaled-down slow sand filters can accurately reproduce the water quality and microbial consortia of full-scale slow sand filters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Point-of-use water purification using clay pot water filters and copper ...

    African Journals Online (AJOL)

    2011-11-24

    Nov 24, 2011 ... clay pot water filters (CPWFs) were fabricated using terracotta clay and sawdust. The sawdust was .... developed by educational initiatives and non-governmental .... est filtration rate, it had the disadvantage of not being able to.

  6. Rotating carbon nanotube membrane filter for water desalination

    Science.gov (United States)

    Tu, Qingsong; Yang, Qiang; Wang, Hualin; Li, Shaofan

    2016-01-01

    We have designed a porous nanofluidic desalination device, a rotating carbon nanotube membrane filter (RCNT-MF), for the reverse osmosis desalination that can turn salt water into fresh water. The concept as well as design strategy of RCNT-MF is modeled, and demonstrated by using molecular dynamics simulation. It has been shown that the RCNT-MF device may significantly improve desalination efficiency by combining the centrifugal force propelled reverse osmosis process and the porous CNT-based fine scale selective separation technology. PMID:27188982

  7. Point-of-use water purification using clay pot water filters and copper ...

    African Journals Online (AJOL)

    All other critical parameters such as total hardness, turbidity, electrical conductivity and ions in the filtered water were also within acceptable levels for drinking water quality. The filtration rate of the pot was also measured as a function of grain size of the sawdust and height of the water column in it. The filtration rate was ...

  8. REMOVING BIOMASS FROM WATER PONDS AND SMALL WATER RESERVOIRS BY USING NON-WOVEN FILTERS

    Directory of Open Access Journals (Sweden)

    Jakub Nieć

    2015-10-01

    Full Text Available 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 verify the possibility of using this type of filters for water originating from small water body purification. The effectiveness of filters were tested on the water originating from the garden pond, contained high levels of nutrients and intensive algal bloom. Research was carried out on three filters (each filter consisted of four geotextile TS 20 layers. Basic water quality indicators: total suspended solids, turbidity, COD and BOD5, temperature, pH and dissolved oxygen were measured. The research results can be considered as satisfactory in terms of mechanical treatment (removal of turbidity and total suspended solids. An important positive effect of the filters was the oxygenation of the treated water, which is especially important for fish.

  9. Use, microbiological effectiveness and health impact of a household water filter intervention in rural Rwanda-A matched cohort study.

    Science.gov (United States)

    Kirby, Miles A; Nagel, Corey L; Rosa, Ghislaine; Umupfasoni, Marie Mediatrice; Iyakaremye, Laurien; Thomas, Evan A; Clasen, Thomas F

    2017-08-01

    Unsafe drinking water is a substantial health risk contributing to child diarrhoea. We investigated impacts of a program that provided a water filter to households in rural Rwandan villages. We assessed drinking water quality and reported diarrhoea 12-24 months after intervention delivery among 269 households in the poorest tertile with a child under 5 from 9 intervention villages and 9 matched control villages. We also documented filter coverage and use. In Round 1 (12-18 months after delivery), 97.4% of intervention households reported receiving the filter, 84.5% were working, and 86.0% of working filters contained water. Sensors confirmed half of households with working filters filled them at least once every other day on average. Coverage and usage was similar in Round 2 (19-24 months after delivery). The odds of detecting faecal indicator bacteria in drinking water were 78% lower in the intervention arm than the control arm (odds ratio (OR) 0.22, 95% credible interval (CrI) 0.10-0.39, p<0.001). The intervention arm also had 50% lower odds of reported diarrhoea among children <5 than the control arm (OR=0.50, 95% CrI 0.23-0.90, p=0.03). The protective effect of the filter is also suggested by reduced odds of reported diarrhoea-related visits to community health workers or clinics, although these did not reach statistical significance. Copyright © 2017 Elsevier GmbH. All rights reserved.

  10. Filtering Water by Use of Ultrasonically Vibrated Nanotubes

    Science.gov (United States)

    Gavalas, Lillian Susan

    2009-01-01

    Devices that could be characterized as acoustically driven molecular sieves have been proposed for filtering water to remove all biological contaminants and all molecules larger than water molecules. Originally intended for purifying wastewater for reuse aboard spacecraft, these devices could also be attractive for use on Earth in numerous settings in which there are requirements to obtain potable, medical-grade, or otherwise pure water from contaminated water supplies. These devices could also serve as efficient means of removing some or all water from chemical products . for example, they might be useful as adjuncts or substitutes for stills in the removal of water from alcohols and alcoholic beverages. These devices may be constructed using various materials, such as ceramics, metallics, or polymers, depending on end-use requirements. A representative device of this type (see figure) would include a polymeric disk, about 1 mm in diameter and between 1 and 40 microns thick, within which would be embedded single-wall carbon nanotubes aligned along the thickness axis. The polymeric disk would be part of a unitary polymeric ring assembly. An acoustic transducer in the form of a piezoelectric-film-and-electrode subassembly - typically 9 microns thick and made of poly(vinylidene fluoride) coated with copper 150 nm thick -. would be affixed to the outside of the outer polymeric ring by means of an electrically nonconductive epoxy. The nanotubes would be chosen to have diameters between about 8 and about 13.5 A because water molecules could fit into the nanotubes, but larger molecules could not. Water to be purified would be placed in contact with one face (typically, the upper face) of the filter disk. The surface tension of water is low enough that water molecules should enter and travel along the nanotubes, and computational simulations of molecular dynamics and experimental measurements have shown that the water molecules inside the nanotubes in this size range can

  11. Arsenic removal from drinking water by a household sand filter in Vietnam--effect of filter usage practices on arsenic removal efficiency and microbiological water quality.

    Science.gov (United States)

    Nitzsche, Katja Sonja; Lan, Vi Mai; Trang, Pham Thi Kim; Viet, Pham Hung; Berg, Michael; Voegelin, Andreas; Planer-Friedrich, Britta; Zahoransky, Jan; Müller, Stefanie-Katharina; Byrne, James Martin; Schröder, Christian; Behrens, Sebastian; Kappler, Andreas

    2015-01-01

    Household sand filters are applied to treat arsenic- and iron-containing anoxic groundwater that is used as drinking water in rural areas of North Vietnam. These filters immobilize poisonous arsenic (As) via co-oxidation with Fe(II) and sorption to or co-precipitation with the formed Fe(III) (oxyhydr)oxides. However, information is lacking regarding the effect of the frequency and duration of filter use as well as of filter sand replacement on the residual As concentrations in the filtered water and on the presence of potentially pathogenic bacteria in the filtered and stored water. We therefore scrutinized a household sand filter with respect to As removal efficiency and the presence of fecal indicator bacteria in treated water as a function of filter operation before and after sand replacement. Quantification of As in the filtered water showed that periods of intense daily use followed by periods of non-use and even sand replacement did not significantly (psand replacement, CFUs of Escherichia coli of sand filters regarding As removal, but indicate a potential risk for human health arising from the enrichment of coliform bacteria during filtration and from E. coli cells that are introduced by sand replacement. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Endocrine disruptors in water filters used in the Rio dos Sinos Basin region, Southern Brazil

    OpenAIRE

    Furtado,CM; von Mühlen,C

    2015-01-01

    The activated carbon filter is used in residences as another step in the treatment of drinking water, based on a physical-chemical process to absorb pollutants that are not removed in conventional treatment. Endocrine disruptors (EDCs) are exogenous substances or mixtures of substances that acts on the endocrine system similarly to the endogenously produced hormones, triggering malfunctions and harmful changes to human and animal health. The objective of the present work was to study EDCs thr...

  13. Research of process of filtration of salt water by bulk filters with the use of vibration

    Directory of Open Access Journals (Sweden)

    A. I. Krikun

    2018-01-01

    Full Text Available For the purification of process water from impurities at fish processing plants, a large number of filtering devices are currently used, differing in their design parameters (mesh, woven, disco, etc.. However, in practice, these filtering devices are mainly used as the first stage of water treatment, since they can not provide sufficient quality of the filtrate. The most effective, as numerous studies of scientists of our country and the world show, are bulk granular filters. Their main advantages over other devices of similar designation are: they have a simple and reliable design; resistant to aggressive operating conditions; they are capable of effectively purifying seawater from mechanical impurities at relatively low pressure; most economical; have a filtering load capable of a long time to work without regeneration (the approximate service life of a grain-loading is 3 to 5 years etc. In this article, the influence of vibration effects on the filtration of sea water in a designed and fabricated filter unit with bulk granular materials of natural and artificial origin, the design of which is protected by two patents for the utility model. The results of the study are presented, revealing the degree of influence of the intensity of vibration of the perforated partitioning wall on the state of bulk granular materials located on it (segregation by size, stratified vibro-packing, compacting or loosening of a layer of granular material. The dependences of the capacity of the filtration unit on the amplitude, frequency and the vibration intensity factor have been experimentally established, which made it possible to establish rational vibration parameters of the perforated septum, under which the filtering layer becomes denser, the porosity of the loading decreases, and the precipitate does not break into the filtrate.

  14. Submerged Pond Sand Filter-A Novel Approach to Rural Water Supply

    DEFF Research Database (Denmark)

    Øhlenschlæger, Mia; Christensen, Sarah Christine Boesgaard; Bregnhøj, Henrik

    2016-01-01

    This study describes the new design and function of a modified version of a traditional slow sand filter. The Submerged Pond Sand Filter is built inside a pond and has a vertical as well as a horizontal flow of water through a sloped filter opening. The filter provides treated drinking water...... to a rural Indian village. The filter has functioned with minimal maintenance for five years without being subject to the typical scraping off and changing of sand as needed in traditional slow sand filters every few months. This five-year study showed bacterial removal efficiency of 97% on average...... to 10 CFU/100 mL on average compared to shorter pumping intervals (5 min). Though the treated water did not comply with the World Health Organization standards of 0 CFU/100 mL, the filter significantly improved water quality and provided one of the best sources of drinkable water in a water...

  15. Water risk assessment in China based on the improved Water Risk Filter

    Science.gov (United States)

    Hong, G.; Yaqin, Q.; Qiong, L.; Cunwen, N.; Na, W.; Jiajia, L.; Jongde, G.; Na, Z.; Xiangyi, D.

    2014-09-01

    Finding an effective way to deal with the water crisis and the relationship between water and development is a major issue for all levels of government and different economic sectors across the world. Scientific understanding of water risk is the basis for achieving a scientific relationship between water and development, and water risk assessment is currently an important research focus. To effectively deal with the global water crisis, the World Wide Fund for Nature and German Investment and Development Company Limited proposed the concept of water risk and released an online Water Risk Filter in March 2012, which has been applied to at least 85 countries. To comprehensively and accurately reflect the situation of water risk in China, this study adjusts the water risk assessment indicators in the Water Risk Filter, taking the actual situation in China and the difficulty of obtaining the information about the indicators into account, and proposes an index system for water risk evaluation for China which consists of physical risk, regulatory risk and reputational risk. The improved Water Risk Filter is further used to assess the sources and causes of the water risks in 10 first-class and seven second-class water resource areas (WRAs). The results indicate that the water risk for the whole country is generally medium and low, while those for different regions in the country vary greatly, and those for southern regions are generally lower than those for northern regions. Government regulatory and policy implementation as well as media supervision in northern regions should be strengthened to reduce the water risk. The research results may provide decision support and references for both governments and industrial enterprises in identifying water risks, formulating prevention and control policies, and improving water resources management in China.

  16. Water risk assessment in China based on the improved Water Risk Filter

    Directory of Open Access Journals (Sweden)

    G. Hong

    2014-09-01

    Full Text Available Finding an effective way to deal with the water crisis and the relationship between water and development is a major issue for all levels of government and different economic sectors across the world. Scientific understanding of water risk is the basis for achieving a scientific relationship between water and development, and water risk assessment is currently an important research focus. To effectively deal with the global water crisis, the World Wide Fund for Nature and German Investment and Development Company Limited proposed the concept of water risk and released an online Water Risk Filter in March 2012, which has been applied to at least 85 countries. To comprehensively and accurately reflect the situation of water risk in China, this study adjusts the water risk assessment indicators in the Water Risk Filter, taking the actual situation in China and the difficulty of obtaining the information about the indicators into account, and proposes an index system for water risk evaluation for China which consists of physical risk, regulatory risk and reputational risk. The improved Water Risk Filter is further used to assess the sources and causes of the water risks in 10 first-class and seven second-class water resource areas (WRAs. The results indicate that the water risk for the whole country is generally medium and low, while those for different regions in the country vary greatly, and those for southern regions are generally lower than those for northern regions. Government regulatory and policy implementation as well as media supervision in northern regions should be strengthened to reduce the water risk. The research results may provide decision support and references for both governments and industrial enterprises in identifying water risks, formulating prevention and control policies, and improving water resources management in China.

  17. Assessment of a membrane drinking water filter in an emergency setting.

    Science.gov (United States)

    Ensink, Jeroen H J; Bastable, Andy; Cairncross, Sandy

    2015-06-01

    The performance and acceptability of the Nerox(TM) membrane drinking water filter were evaluated among an internally displaced population in Pakistan. The membrane filter and a control ceramic candle filter were distributed to over 3,000 households. Following a 6-month period, 230 households were visited and filter performance and use were assessed. Only 6% of the visited households still had a functioning filter, and the removal performance ranged from 80 to 93%. High turbidity in source water (irrigation canals), together with high temperatures and large family size were likely to have contributed to poor performance and uptake of the filters.

  18. Analysis of UV filters in tap water and other clean waters in Spain.

    Science.gov (United States)

    Díaz-Cruz, M Silvia; Gago-Ferrero, Pablo; Llorca, Marta; Barceló, Damià

    2012-03-01

    The present paper describes the development of a method for the simultaneous determination of five hormonally active UV filters namely benzophenone-3 (BP3), 3-(4-methylbenzylidene) camphor (4MBC), 2-ethylhexyl 4-(dimethylamino) benzoate (OD-PABA), 2-ethylhexyl 4-methoxycinnamate (EHMC) and octocrylene (OC) by means of solid-phase extraction and gas chromatography-electron impact ionization-mass spectrometry. Under optimized conditions, this methodology achieved low method limits of detection (needed for clean waters, especially drinking water analysis), between 0.02 and 8.42 ng/L, and quantitative recovery rates higher than 73% in all cases. Inter- and intraday precision for all compounds were lower than 7% and 11%, respectively. The optimized methodology was applied to perform the first survey of UV absorbing compounds in tap water from the metropolitan area and the city of Barcelona (Catalonia, Spain). In addition, other types of clean water matrices (mineral bottled water, well water and tap water treated with an ion-exchange resin) were investigated as well. Results evidenced that all the UV filters investigated were detected in the water samples analyzed. The compounds most frequently found were EHMC and OC. Maximum concentrations reached in tap water were 290 (BP3), 35 (4MBC), 110 (OD-PABA), 260 (EHMC), and 170 ng/L (OC). This study constitutes the first evidence of the presence of UV filter residues in tap water in Europe.

  19. Endocrine disruptors in water filters used in the Rio dos Sinos Basin region, Southern Brazil

    Directory of Open Access Journals (Sweden)

    CM Furtado

    Full Text Available The activated carbon filter is used in residences as another step in the treatment of drinking water, based on a physical-chemical process to absorb pollutants that are not removed in conventional treatment. Endocrine disruptors (EDCs are exogenous substances or mixtures of substances that acts on the endocrine system similarly to the endogenously produced hormones, triggering malfunctions and harmful changes to human and animal health. The objective of the present work was to study EDCs through semi-quantitative analysis of residential water filters collected in the region of Rio dos Sinos basin, focusing on two specific classes: hormones and phenols. The solid phase extraction principle was used for the extraction of compounds and gas chromatography coupled with mass spectrometry for the separation and characterization of EDCs. Four samples of residential filters collected from public water distribution and artesian wells, from the cities of Novo Hamburgo and São Leopoldo were analysed. Using the developed methodology, it was possible to detect and comparatively quantify selected EDCs in all studied samples, which indicates the presence of these contaminants in drinking water from different sources.

  20. An Improved Cambridge Filter Pad Extraction Methodology to Obtain More Accurate Water and “Tar” Values: In Situ Cambridge Filter Pad Extraction Methodology

    Directory of Open Access Journals (Sweden)

    Ghosh David

    2014-07-01

    Full Text Available Previous investigations by others and internal investigations at Philip Morris International (PMI have shown that the standard trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387 (Cigarettes -- Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine, is not suitable for high-water content aerosols. Errors occur because of water losses during the opening of the Cambridge filter pad holder to remove the filter pad as well as during the manual handling of the filter pad, and because the commercially available filter pad holder, which is constructed out of plastic, may adsorb water. This results in inaccurate values for the water content, and erroneous and overestimated values for Nicotine Free Dry Particulate Matter (NFDPM. A modified 44 mm Cambridge filter pad holder and extraction equipment which supports in situ extraction methodology has been developed and tested. The principle of the in situ extraction methodology is to avoid any of the above mentioned water losses by extracting the loaded filter pad while kept in the Cambridge filter pad holder which is hermetically sealed by two caps. This is achieved by flushing the extraction solvent numerous times through the hermetically sealed Cambridge filter pad holder by means of an in situ extractor. The in situ methodology showed a significantly more complete water recovery, resulting in more accurate NFDPM values for high-water content aerosols compared to the standard ISO methodology. The work presented in this publication demonstrates that the in situ extraction methodology applies to a wider range of smoking products and smoking regimens, whereas the standard ISO methodology only applies to a limited range of smoking products and smoking regimens, e.g., conventional cigarettes smoked under ISO smoking regimen. In cases where a comparison of yields between the PMI HTP and

  1. Measurement of Water Quality Parameters for Before and After Maintenance Service in Water Filter System

    Directory of Open Access Journals (Sweden)

    Shaharudin Nuraida

    2017-01-01

    Full Text Available An adequate supply of safe drinking water is one of major ways to obtain healthy life. Water filter system is one way to improve the water quality. However, to maintain the performance of the system, it need to undergo the maintenance service. This study evaluate the requirement of maintenance service in water filter system. Water quality was measured before and after maintenance service. Parameters measured were pH, turbidity, residual chlorine, nitrate and heavy metals and these parameters were compared with National Drinking Water Quality Standards. Collection of data were involved three housing areas in Johor. The quality of drinking water from water filter system were analysed using pH meter, turbidity meter, DR6000 and Inductively Coupled Plasma-Mass Spectrometer. pH value was increased from 16.4% for before maintenance services to 30.7% for after maintenance service. Increment of removal percentage for turbidity, residual chlorine and nitrate after maintenance were 21.5, 13.6 and 26.7, respectively. This result shows that maintenance service enhance the performance of the system. However, less significant of maintenance service for enhance the removal of heavy metals which the increment of removal percentage in range 0.3 to 9.8. Only aluminium shows percentage removal for after maintenance with 92.8% lower compared to before maintenance service with 95.5%.

  2. Development of anti-debris filter for WWER-440 working fuel assembly

    International Nuclear Information System (INIS)

    Kolosovsky, V.; Aksyonov, P.; Kukushkin, Y.; Molchanov, V.; Kolobaev, A.

    2006-01-01

    Mechanical damaging of the fuel rod claddings caused by debris is one of the main reasons for fuel assembly failures. The paper focuses on the program and results of experimental and design activities carried out by Russian organizations relating to the development and investigation of operational characteristics of anti-debris filters for WWER-440 working fuel assemblies. Lead working fuel assemblies equipped with anti-debris filters have been loaded in the core of Kola-2 NPP. The results obtained can be used for making the decision concerning the application of anti-debris filter for WWER-440 working fuel assemblies with the purpose of enhancing their debris-resistance properties. (authors)

  3. Effectiveness of table top water pitcher filters to remove arsenic from drinking water.

    Science.gov (United States)

    Barnaby, Roxanna; Liefeld, Amanda; Jackson, Brian P; Hampton, Thomas H; Stanton, Bruce A

    2017-10-01

    Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As 3+ and As 5+ , from 1000μg/L to water and its use reduces plastic waste associated with bottled water. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. A New Electropositive Filter for Concentrating Enterovirus and Norovirus from Large Volumes of Water - MCEARD

    Science.gov (United States)

    The detection of enteric viruses in environmental water usually requires the concentration of viruses from large volumes of water. The 1MDS electropositive filter is commonly used for concentrating enteric viruses from water but unfortunately these filters are not cost-effective...

  5. Silver Nanoparticles (AgNP impregnated filters in drinking water disinfection

    Directory of Open Access Journals (Sweden)

    Rus Alexandru

    2017-01-01

    Full Text Available This paper describes how simple portable devices could eliminate water pathogens by using Silver Nanoparticles, based on their antimicrobial properties. Recent studies indicated that silver nanoparticles can achieve up to 100% antibacterial activity removal. Results are showing that Silver Nanoparticles retention in the filter structure, E. coli bacteria removal, water quality and water flow rate must be evaluated as main efficiency indicators of the designed filters, in order to obtain the optimal filter. To apply the antimicrobial property of Silver in drinking-water treatment, a filter is produced using Additive Manufacturing techniques and coated with different concentrations of silver solutions.

  6. Clinical and Microbiologic Efficacy of a Water Filter Program in a Rural Honduran Community

    Directory of Open Access Journals (Sweden)

    Jaclyn Arquiette

    2014-01-01

    Full Text Available Water purification in the rural Honduras is a focus of the nonprofit organization Honduras Outreach Medical Brigade Relief Effort (HOMBRE. We assessed water filter use and tested filter microbiologic and clinical efficacy. A 22-item questionnaire assessed water sources, obtainment/storage, purification, and incidence of gastrointestinal disease. Samples from home clay-based filters in La Hicaca were obtained and paired with surveys from the same home. We counted bacterial colonies of four bacterial classifications from each sample. Sixty-five surveys were completed. Forty-five (69% individuals used a filter. Fifteen respondents reported diarrhea in their home in the last 30 days; this incidence was higher in homes not using a filter. Thirty-three paired water samples and surveys were available. Twenty-eight samples (85% demonstrated bacterial growth. A control sample was obtained from the local river, the principal water source; number and bacterial colony types were innumerable within 24 hours. Access to clean water, the use of filters, and other treatment methods differed within a geographically proximal region. Although the majority of the water samples failed to achieve bacterial eradication, water filters may sufficiently reduce bacterial coliform counts to levels below infectious inoculation. Clay water filters may be sustainable water treatment measures in resource poor settings.

  7. Characterization of the relationship between ceramic pot filter water production and turbidity in source water.

    Science.gov (United States)

    Salvinelli, Carlo; Elmore, A Curt; Reidmeyer, Mary R; Drake, K David; Ahmad, Khaldoun I

    2016-11-01

    Ceramic pot filters represent a common and effective household water treatment technology in developing countries, but factors impacting water production rate are not well-known. Turbidity of source water may be principal indicator in characterizing the filter's lifetime in terms of water production capacity. A flow rate study was conducted by creating four controlled scenarios with different turbidities, and influent and effluent water samples were tested for total suspended solids and particle size distribution. A relationship between average flow rate and turbidity was identified with a negative linear trend of 50 mLh -1 /NTU. Also, a positive linear relationship was found between the initial flow rate of the filters and average flow rate calculated over the 23 day life of the experiment. Therefore, it was possible to establish a method to estimate the average flow rate given the initial flow rate and the turbidity in the influent water source, and to back calculate the maximum average turbidity that would need to be maintained in order to achieve a specific average flow rate. However, long-term investigations should be conducted to assess how these relationships change over the expected CPF lifetime. CPFs rejected fine suspended particles (below 75 μm), especially particles with diameters between 0.375 μm and 10 μm. The results confirmed that ceramic pot filters are able to effectively reduce turbidity, but pretreatment of influent water should be performed to avoid premature failure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Performance test of filtering system for controlling the turbidity of secondary cooling water in HANARO

    International Nuclear Information System (INIS)

    Park, Y. C.; Woo, J. S.; Jo, Y. K.; Loo, J. S.; Lim, N. Y.

    2001-01-01

    There is about 80 m 3 /h loss of the secondary cooling water by evaporation, windage and blowdown during the operation of HANARO, 30 MW research reactor. When the secondary cooling water is treated by high Ca-hardness treatment program for minimizing the blowdown loss, only the trubidity exceeds the limit. By adding filtering system it was confirned, through the relation of turbidity and filtering rate of secondary cooling water, that the turbidity is reduced below the limit (5 deg.) by 2 % of filtering rate without blowdown. And it was verified, through the field performace test of filtering system under normal operation condition, that the circulation pumps get proper capacity and that filter units reduce the turbidity below the limit. Therefore, the secondary cooling water can be treated by the high Ca-hardness program and filter system without blowdown

  9. Bacterial treatment effectiveness of point-of-use ceramic water filters.

    Science.gov (United States)

    Bielefeldt, Angela R; Kowalski, Kate; Summers, R Scott

    2009-08-01

    Laboratory experiments were conducted on six point-of-use (POU) ceramic water filters that were manufactured in Nicaragua; two filters were used by families for ca. 4 years and the other filters had limited prior use in our lab. Water spiked with ca. 10(6)CFU/mL of Escherichia coli was dosed to the filters. Initial disinfection efficiencies ranged from 3 - 4.5 log, but the treatment efficiency decreased with subsequent batches of spiked water. Silver concentrations in the effluent water ranged from 0.04 - 1.75 ppb. Subsequent experiments that utilized feed water without a bacterial spike yielded 10(3)-10(5)CFU/mL bacteria in the effluent. Immediately after recoating four of the filters with a colloidal silver solution, the effluent silver concentrations increased to 36 - 45 ppb and bacterial disinfection efficiencies were 3.8-4.5 log. The treatment effectiveness decreased to 0.2 - 2.5 log after loading multiple batches of highly contaminated water. In subsequent loading of clean water, the effluent water contained filters. This indicates that the silver had some benefit to reducing bacterial contamination by the filter. In general these POU filters were found to be effective, but showed loss of effectiveness with time and indicated a release of microbes into subsequent volumes of water passed through the system.

  10. Effect of Chitosan Binder on Water Absorption of Empty Fruit Bunches Filter Media

    International Nuclear Information System (INIS)

    Aziatul Niza Sadikin; Mohd Ghazali Mohd Nawawi; Norasikin Othman

    2015-01-01

    The potential of chitosan as filter media binder was investigated in this study. Chitosan solution with different concentrations were applied to the empty fruit bunches using two different deposition techniques, namely, spray method and addition method. In this study, a water absorption test was used to study the sorption behaviour of empty fruit bunches filter media. The water absorption study showed that the water uptake for empty fruit bunches filter media without the chitosan binder increases with time, until the water sorption reaches the equilibrium state. It was observed that the water uptake decreased from 23 % to 14 % for the chitosan-filled filter media as compared to binder-less filter media, over the duration of 24 hours. For 1 % chitosan concentration, the water uptake is higher compared to 3 % chitosan-filled filter media. The water absorption is relatively lower for filter media with a higher concentration of chitosan due to the high compatibility achieved at this interfacial region between empty fruit bunches fibres and chitosan. Alkali-treated filter media showed the lowest water uptake compared to diethyl ether, ethanol and hot water pretreatment methods. (author)

  11. Preliminary analysis on the water quality index (WQI) of irradiated basic filter elements

    Science.gov (United States)

    Arif Abu Bakar, Asyraf; Muhamad Pauzi, Anas; Aziz Mohamed, Abdul; Syima Sharifuddin, Syazrin; Mohamad Idris, Faridah

    2018-01-01

    Simple water filtration system is needed in times of extreme floods. Clean water for sanitation at evacuation centres is essential and its production is possible by using the famous simple filtration system consisting of empty bottle and filter elements (sands, gravels, cotton/coffee filter). This research intends to study the effects of irradiated filter elements on the filtration effectiveness through experiments. The filter elements will be irradiated with gamma and neutron radiation using the facilities available at Malaysia Nuclear Agency. The filtration effectiveness is measured using the water quality index (WQI) that is developed in this study to reflect the quality of filtered water. The WQI of the filtered water using the system with irradiated filter elements is then compared with that of the system with non-irradiated filter elements. This preliminary analysis only focus on filtration element of silica sand. Results shows very nominal variation in in WQI after filtered by non-irradiated, gamma and neutron filter element (silica sand), where the hypothesis could not be affirmed.

  12. Processes of microbial pesticide degradation in rapid sand filters for treatment of drinking water

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    Aerobic rapid sand filters for treatment of groundwater at waterworks were investigated for the ability to remove pesticides. The potential, kinetics and mechanisms of microbial pesticide removal was investigated in microcosms consisting of filter sand, treated water and pesticides in initial...... concentrations of 0.04-2.4 μg/L. The pesticides were removed from the water in microcosms with filter sand from all three investigated sand filters. Within the experimental periode of six to 13 days, 65-85% of the bentazone, 86-93% of the glyphosate, 97-99% of the p-nitrophenol was removed from the water phase...

  13. Sustainable colloidal-silver-impregnated ceramic filter for point-of-use water treatment.

    Science.gov (United States)

    Oyanedel-Craver, Vinka A; Smith, James A

    2008-02-01

    Cylindrical colloidal-silver-impregnated ceramic filters for household (point-of-use) water treatment were manufactured and tested for performance in the laboratory with respect to flow rate and bacteria transport. Filters were manufactured by combining clay-rich soil with water, grog (previously fired clay), and flour, pressing them into cylinders, and firing them at 900 degrees C for 8 h. The pore-size distribution of the resulting ceramic filters was quantified by mercury porosimetry. Colloidal silver was applied to filters in different quantities and ways (dipping and painting). Filters were also tested without any colloidal-silver application. Hydraulic conductivity of the filters was quantified using changing-head permeability tests. [3H]H2O water was used as a conservative tracer to quantify advection velocities and the coefficient of hydrodynamic dispersion. Escherichia coli (E. coli) was used to quantify bacterial transport through the filters. Hydraulic conductivity and pore-size distribution varied with filter composition; hydraulic conductivities were on the order of 10(-5) cm/s and more than 50% of the pores for each filter had diameters ranging from 0.02 to 15 microm. The filters removed between 97.8% and 100% of the applied bacteria; colloidal-silver treatments improved filter performance, presumably by deactivation of bacteria. The quantity of colloidal silver applied per filter was more important to bacteria removal than the method of application. Silver concentrations in effluent filter water were initially greater than 0.1 mg/L, but dropped below this value after 200 min of continuous operation. These results indicate that colloidal-silver-impregnated ceramic filters, which can be made using primarily local materials and labor, show promise as an effective and sustainable point-of-use water treatment technology for the world's poorest communities.

  14. A HYBRID FILTER AND WRAPPER FEATURE SELECTION APPROACH FOR DETECTING CONTAMINATION IN DRINKING WATER MANAGEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    S. VISALAKSHI

    2017-07-01

    Full Text Available Feature selection is an important task in predictive models which helps to identify the irrelevant features in the high - dimensional dataset. In this case of water contamination detection dataset, the standard wrapper algorithm alone cannot be applied because of the complexity. To overcome this computational complexity problem and making it lighter, filter-wrapper based algorithm has been proposed. In this work, reducing the feature space is a significant component of water contamination. The main findings are as follows: (1 The main goal is speeding up the feature selection process, so the proposed filter - based feature pre-selection is applied and guarantees that useful data are improbable to be detached in the initial stage which discussed briefly in this paper. (2 The resulting features are again filtered by using the Genetic Algorithm coded with Support Vector Machine method, where it facilitates to nutshell the subset of features with high accuracy and decreases the expense. Experimental results show that the proposed methods trim down redundant features effectively and achieved better classification accuracy.

  15. Do low-cost ceramic water filters improve water security in rural South Africa?

    Science.gov (United States)

    Lange, Jens; Materne, Tineke; Grüner, Jörg

    2016-10-01

    This study examined the performance of a low-cost ceramic candle filter system (CCFS) for point of use (POU) drinking water treatment in the village of Hobeni, Eastern Cape Province, South Africa. CCFSs were distributed in Hobeni and a survey was carried out among their users. The performance of 51 CCFSs was evaluated by dip slides and related to human factors. Already after two-thirds of their specified lifetime, none of the distributed CCFSs produced water without distinct contamination, and more than one-third even deteriorated in hygienic water quality. Besides the water source (springs were preferable compared to river or rain water), a high water throughput was the dominant reason for poor CCFS performance. A stepwise laboratory test documented the negative effects of repeated loading and ambient field temperatures. These findings suggest that not every CCFS type per se guarantees improved drinking water security and that the efficiency of low-cost systems should continuously be monitored. For this purpose, dip slides were found to be a cost-efficient alternative to standard laboratory tests. They consistently underestimated microbial counts but can be used by laypersons and hence by the users themselves to assess critical contamination of their filter systems.

  16. Performance of water filters towards the removal of selected ...

    African Journals Online (AJOL)

    Organic matter removal was found to be 47%, 43%, 53%, 43.4% for bio-sand, slow sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% for bone char filter. Furthermore, filters were also assessed in terms of media availability, buying costs, operation, benefits/ effectiveness ...

  17. Storm Water Pollution Removal Performance of Compost Filter Socks

    Science.gov (United States)

    In 2005, the US Environmental Protection Agency National Menu of Best Management Practices (BMPs) listed compost filter socks as an approved BMP for controlling sediment in storm runoff on construction sites. Filtrexx International manufactures and distributes Filter Soxx (FS). Literature suggests...

  18. The security management of spent filter cartridge in Qinshan phase 3 (heavy water reactor) nuclear power plant

    International Nuclear Information System (INIS)

    Xue Dahai

    2005-01-01

    Qinshan phase 3 nuclear power plant is the first CANDU plant that China fetched in from Canada, and both two units operate under well condition up to now. The radioactive wastes produced during the unit operation mainly include technical waste, spent resin, and spent filter cartridge. The spent filter cartridge is one important part both in the volume and radioactivity of the radioactive waste, and it is the important content of radioactive waste management. Different from PWR, part of high radioactive spent filter in CANDU unit comes from heavy water system such as moderator system. It has to be dried through blowing before replaced from the system. But this working procedure result the filtrate dreg become flexible, and it can bring on the risk of internal or external exposure. It is very important to pay high attention to control the contamination spread during spent filter inside transfer. (authors)

  19. Behavior of the polygonal HEPA filter exposed to water droplets carried by the offgas flow

    International Nuclear Information System (INIS)

    Jannakos, K.; Potgeter, G.; Legner, W.

    1991-01-01

    A polygonal high-efficiency particulate air (HEPA) filter element has been developed and tested with a view to cleaning the dissolver offgas from reprocessing plants. It is likewise suited to filter process offgases generated in other plants. Due to its high dew point (about 30 degree C) the dissolver offgas, before being directed into the HEPA filter, is heated with a gas heater to approx. 100 degree C so that condensation in the pipework upstream of the filter and in the filter proper is avoided. In case of failure of the heater the offgas may undergo condensation upstream of the HEPA filter until it is bypassed to a standby heater or a standby filter system. Consequently, the filter may be loaded with water droplets. therefore, experiments have been performed with a view to estimating the behavior of the polygonal filter element when exposed to condensate droplets in a real plant. According to the experiments performed so far it can be anticipated that in case of failure of the heater the amount of condensate produced until bypassing to a standby system will not damage a new or little loaded polygonal filter element. The experiments will be carried on with the goal of investigating the behavior of a heavily loaded polygonal filter element exposed to water droplets

  20. Results from measurements of natural radiation in and from filters in some water treatment plants; Maetningar av naturlig radioaktivitet i och fraan filter vid naagra vattenverk

    Energy Technology Data Exchange (ETDEWEB)

    Oestergren, Inger; Aakerblom, Gustav [Swedish Radiation Protection Authority, Stockholm (Sweden); Ek, Britt-Marie [Geological Survey of Sweden, Uppsala (Sweden)

    2005-07-01

    Large water treatment plants often process surface water where the concentration of natural radionuclides is so low that treatment of the water produces no radiation dose or waste problem. The level of natural radionuclides in ground water is higher than in surface water and often so high that mitigation is needed to clean the water. Specific treatment of the filters and filter masses is needed in some cases because the natural radionuclides precipitate in the filters. The radiation doses received by personnel at the ground water treatment plants are often low because of the relatively short time the workers spend inside the treatment plant. The results presented here indicate no need for extra action to insure radiation protection with regard to radioactivity inside the treatment plant or during processing of the filters and waste. A comprehensive discussion of the problems associated with the concentrating of natural radionuclides in water filters is presented in this report.

  1. Stratification of nitrification activity in rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Musovic, Sanin

    2013-01-01

    Rapid sand filters used in groundwater treatment remove ammonium, iron and manganese from the water. Ammonium is removed biologically by nitrifying microorganisms attached on the sand surface. Nitrification kinetics and activity is strongly affected by filter design and operation, which are the key...... and maximum nitrification capacity are derived and used to quantify nitrification activity. Nitrification activity was concentrated at the top 10 cm of filter depth, and maximum nitrification capacity was 7 g NH4+-N/ m3 sand/h compared with 0.8-0.4 g NH4+-N/ m3 sand/h in the middle and bottom layers. A water...... of this study is to investigate nitrification activity in a rapid sand filter, with focus on its homogeneity and how it relates to filter performance. Two groundwater treatment plants in Denmark were selected for the experimental investigations. Plant 1 operates a single line of pre and after filters and has...

  2. A New Method for the Deposition of Metallic Silver on Porous Ceramic Water Filters

    Directory of Open Access Journals (Sweden)

    Kathryn N. Jackson

    2018-01-01

    Full Text Available A new method of silver application to a porous ceramic water filter used for point-of-use water treatment is developed. We evaluated filter performance for filters manufactured by the conventional method of painting an aqueous suspension of silver nanoparticles onto the filter and filters manufactured with a new method that applies silver nitrate to the clay-water-sawdust mixture prior to pressing and firing the filter. Filters were evaluated using miscible displacement flow-through experiments with pulse and continuous-feed injections of E. coli. Flow characteristics were quantified by tracer experiments using [3H]H2O. Experiments using pulse injections of E. coli showed similar performance in breakthrough curves between the two application methods. Long-term challenge tests performed with a continuous feed of E. coli and growth medium resulted in similar log removal rates, but the removal rate by nanosilver filters decreased over time. Silver nitrate filters provided consistent removal with lower silver levels in the effluent and effective bacterial disinfection. Results from continued use with synthetic groundwater over 4 weeks, with a pulse injection of E. coli at 2 and 4 weeks, support similar conclusions—nanosilver filters perform better initially, but after 4 weeks of use, nanosilver filters suffer larger decreases in performance. Results show that including silver nitrate in the mixing step may effectively reduce costs, improve silver retention in the filter, increase effective lifespan, and maintain effective pathogen removal while also eliminating the risk of exposure to inhalation of silver nanoparticles by workers in developing-world filter production facilities.

  3. Micron-pore-sized metallic filter tube membranes for filtration of particulates and water purification.

    Science.gov (United States)

    Phelps, T J; Palumbo, A V; Bischoff, B L; Miller, C J; Fagan, L A; McNeilly, M S; Judkins, R R

    2008-07-01

    Robust filtering techniques capable of efficiently removing particulates and biological agents from water or air suffer from plugging, poor rejuvenation, low permeance, and high backpressure. Operational characteristics of pressure-driven separations are in part controlled by the membrane pore size, charge of particulates, transmembrane pressure and the requirement for sufficient water flux to overcome fouling. With long term use filters decline in permeance due to filter-cake plugging of pores, fouling, or filter deterioration. Though metallic filter tube development at ORNL has focused almost exclusively on gas separations, a small study examined the applicability of these membranes for tangential filtering of aqueous suspensions of bacterial-sized particles. A mixture of fluorescent polystyrene microspheres ranging in size from 0.5 to 6 microm in diameter simulated microorganisms in filtration studies. Compared to a commercial filter, the ORNL 0.6 microm filter averaged approximately 10-fold greater filtration efficiency of the small particles, several-fold greater permeance after considerable use and it returned to approximately 85% of the initial flow upon backflushing versus 30% for the commercial filter. After filtering several liters of the particle-containing suspension, the ORNL composite filter still exhibited greater than 50% of its initial permeance while the commercial filter had decreased to less than 20%. When considering a greater filtration efficiency, greater permeance per unit mass, greater percentage of rejuvenation upon backflushing (up to 3-fold), and likely greater performance with extended use, the ORNL 0.6 microm filters can potentially outperform the commercial filter by factors of 100-1,000 fold.

  4. Characterization of filters cartridges from the water polishing system of IEA-R1 reactor: radiometric methods

    International Nuclear Information System (INIS)

    Tessaro, Ana Paula G.; Vicente, Roberto

    2015-01-01

    The acceptance of radioactive waste in a repository depends primarily on knowledge of the radioisotopic inventory of the material, according to regulations established by regulatory agencies. The primary characterization is also a fundamental action to determine further steps in the management of the radioactive wastes. The aim of this work is to report the development of non-destructive methods for primary characterization of filters cartridges discarded as radioactive waste. The filters cartridges are used in the water polishing system of the IEA-R1 reactor retaining the particles in suspension in the reactor cooling water. The IEA-R1 is a pool type reactor with a thermal power of 5 MW, moderated and cooled with light water. It is located in the Energy and Nuclear Research Institute (IPEN-CNEN), in São Paulo, Brazil. The cartridge filters become radioactive waste when they are saturated and do not meet the required flow for the proper operation of the water polishing system. The activities of gamma emitters present in the filters are determined using gamma spectrometry, dose rate measurements and the Point Kernel Method to correlate results from both measurements. For the primary characterization, one alternative method is the radiochemical analysis of slices taken from each filter, what presents the disadvantage of higher exposures personnel and contamination risks. Another alternative method is the calibration of the measurement geometry of a gamma spectrometer, which requires the production of a standard filter. Both methods are necessary but can not be used in operational routine of radioactive waste management owing to cost and complexity. The method described can be used to determine routinely the radioactive inventory of these filters and other radioactive wastes, avoiding the necessity of destructive radiochemical analysis, or the necessity of calibrating the geometry of measurement. (author)

  5. Retention of radium from thermal waters on sand filters and adsorbents

    International Nuclear Information System (INIS)

    Elejalde, C.; Herranz, M.; Idoeta, R.; Legarda, F.; Romero, F.; Baeza, A.

    2007-01-01

    This study was focussed on laboratory experiences of retention of radium from one thermal water on sand filters and adsorbents, trying to find an easy method for the elimination in drinkable waters polluted with this natural radio-nuclide. A thermal water from Cantabria (Spain) was selected for this work. Retention experiences were made with columns of 35 mm of diameter containing 15 cm layers of washed river sand or 4 cm layers of zeolite A3, passing known volumes of thermal water at flows between 4 and 40 ml/min with control of the retained radium by determining the amount in the water after the treatment. The statistical analysis of data suggests that retention depends on the flow and the volume passed through the columns. As additional adsorbents were used kaolin and a clay rich in illite. Jar-test experiences were made agitating known weights of adsorbents with the selected thermal water, with addition of flocculants and determination of radium in filtrated water after the treatment. Data suggest that retention is related to the weight of adsorbent used, but important quantities of radium seem remain in solution for higher amounts of adsorbents, according to the statistical treatment of data. The elution of retained radium from columns or adsorbents, previously used in experiences, should be the aim of a future research

  6. Retention of radium from thermal waters on sand filters and adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Elejalde, C. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain)]. E-mail: inpelsac@bi.ehu.es; Herranz, M. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Legarda, F. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Romero, F. [Dpto. de Ingenieria Quimica y del Medio Ambiente, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Baeza, A. [Dpto. de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. Universidad s/n, 10071 Caceres (Spain)

    2007-06-18

    This study was focussed on laboratory experiences of retention of radium from one thermal water on sand filters and adsorbents, trying to find an easy method for the elimination in drinkable waters polluted with this natural radio-nuclide. A thermal water from Cantabria (Spain) was selected for this work. Retention experiences were made with columns of 35 mm of diameter containing 15 cm layers of washed river sand or 4 cm layers of zeolite A3, passing known volumes of thermal water at flows between 4 and 40 ml/min with control of the retained radium by determining the amount in the water after the treatment. The statistical analysis of data suggests that retention depends on the flow and the volume passed through the columns. As additional adsorbents were used kaolin and a clay rich in illite. Jar-test experiences were made agitating known weights of adsorbents with the selected thermal water, with addition of flocculants and determination of radium in filtrated water after the treatment. Data suggest that retention is related to the weight of adsorbent used, but important quantities of radium seem remain in solution for higher amounts of adsorbents, according to the statistical treatment of data. The elution of retained radium from columns or adsorbents, previously used in experiences, should be the aim of a future research.

  7. Filtering and storage working memory networks in younger and older age.

    Science.gov (United States)

    Vellage, Anne-Katrin; Becke, Andreas; Strumpf, Hendrik; Baier, Bernhard; Schönfeld, Mircea Ariel; Hopf, Jens-Max; Müller, Notger G

    2016-11-01

    Working memory (WM) is a multi-component model that among others involves the two processes of filtering and storage. The first reflects the necessity to inhibit irrelevant information from entering memory, whereas the latter refers to the active maintenance of object representations in memory. In this study, we aimed at a) redefining the neuronal networks sustaining filtering and storage within visual working memory by avoiding shortcomings of prior studies, and b) assessing age-related changes in these networks. We designed a new paradigm that strictly controlled for perceptual load by presenting the same number of stimuli in each of three conditions. We calculated fMRI contrasts between a baseline condition (low filter and low storage load) and conditions that posed high demands on filtering and storage, respectively, in large samples of younger ( n  = 40) and elder ( n  = 38) participants. Our approach of comparing contrasts between groups revealed more extensive filter and storage WM networks than previous studies. In the younger group, filtering involved the bilateral insulae, the right occipital cortex, the right brainstem, and the right cerebellum. In the elder group, filtering was associated with the bilateral insulae, right precuneus, and bilateral ventromedial prefrontal cortex. An extensive neuronal network was also found during storage of information in the bilateral posterior parietal cortex, the left ventromedial prefrontal cortex, and the right precuneus in the younger participants. In addition to these brain regions, elder participants recruited the bilateral ventral prefrontal cortex, the superior, middle and inferior and temporal cortex, the left cingulum and the bilateral parahippocampal cortex. In general, elder participants recruited more brain regions in comparison to younger participants to reach similar accuracy levels. Furthermore, in elder participants one brain region emerged in both contrasts, namely the left ventromedial prefrontal

  8. Microbial degradation of pesticides in rapid sand filters for treatment of drinking water

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    2014-01-01

    In Denmark drinking water supply is based on groundwater which is treated by aeration followed by filtration in rapid sand filters. Unfortunately pesticide contamination of the groundwater poses a threat to the water supply, since the simple treatment process at the waterworks is not considered...... to remove pesticides from the water phase and pesticides are detected in 24% of the active Danish waterworks wells. This study aimed at investigating the potential of microbial pesticide removal in rapid sand filters for drinking water treatment. Removal of the pesticides MCPP, bentazone, glyphosate...... and the degradation compound p-nitrophenol was investigated in the rapid sand filters at Islevbro and Sjælsø waterworks plant I and II. Microcosms were set up with sand from rapid sand filters, water and an initial pesticide concentration of 0.03-0.38 μg/L. In all the investigated waterworks the concentration...

  9. High gradient magnetic filters for boiler water treatment

    International Nuclear Information System (INIS)

    Harland, J.R.; Nichols, R.M.

    1977-01-01

    Heavy metal oxide suspended solids in those steam condensates recycled to the boilers produce buildup within the boiler tubes which can lead to unequal and reduced heat transfer efficiency, and indirectly, to boiler tube failures. Recommended reductions in such suspended solids in feedwater to the economizers of modern high pressure boilers to levels of under 10 ppb have been published. The industrially-available SALA-HGMF magnetic filter has achieved these desired suspended solids levels in treating steam condensates. The high gradient magnetic filter has been shown in pilot tests to achieve and even exceed the recommended low level suspended solids in a practical and efficient industrial system. Such electromagnetic filters, when combined with good system chemistry, have achieved low single number parts per billion levels of several heavy metals with very high single-pass efficiencies

  10. Transport of nanoparticles with dispersant through biofilm coated drinking water sand filters.

    Science.gov (United States)

    Li, Zhen; Aly Hassan, Ashraf; Sahle-Demessie, Endalkachew; Sorial, George A

    2013-11-01

    This article characterizes, experimentally and theoretically, the transport and retention of engineered nanoparticles (NP) through sand filters at drinking water treatment plants (DWTPs) under realistic conditions. The transport of four commonly used NPs (ZnO, CeO2, TiO2, and Ag, with bare surfaces and coating agents) through filter beds filled with sands from either acid washed and calcined, freshly acquired filter media, and used filter media from active filter media, were investigated. The study was conducted using water obtained upstream of the sand filter at DWTP. The results have shown that capping agents have a determinant importance in the colloidal stability and transport of NPs through the different filter media. The presence of the biofilm in used filter media increased adsorption of NPs but its effects in retaining capped NPs was less significant. The data was used to build a mathematical model based on the advection-dispersion equation. The model was used to simulate the performance of a scale-up sand filter and the effects on filtration cycle of traditional sand filtration system used in DWTPs. Published by Elsevier Ltd.

  11. Bank filtered water quality characteristics in Okgog-Ri area of Youngsan-River, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hee-Youl; Kim, Hyoung-Soo [Korea Water Resources Corp., Taejeon(Korea)

    2001-02-28

    Preliminary artificial recharge groundwater intake method using bank filtering had been conducted in Okgog-Ri of Youngsan-River to evaluate the possibility of substitution of surface water intake method in the area. In order to investigate the characteristics of bank filtered groundwater, we examined the hydrogeological properties of alluvium and water quality of stream and groundwater. It is observed that nitrate in stream water from synthetic fertilizer and poultry manure is almost consumed during bank filtering in this area. This implies that denitrification of organic carbon and the oxidation of pyrite present in the alluvium aquifer. Groundwater samples from bank filtering show high Mn concentration. This high Mn concentration may be resulted from decreasing redox potential due to denitrification and increasing mobility due to redox reaction of Mn-oxide. In the study area, there is a typical tendency that Al concentrations of water samples decrease according to increasing pH. This tendency is interpreted as forming of amorphous Al(OH){sub 3} precipitates by reducing the Al{sup 3+} solubilities. It is revealed that the bank filtered groundwater in the area is not edible because color, turbidity, heterotrophic bacteria, coliform and Mn of the groundwater exceed the guideline of drinking water. Even though the bank filtered groundwater without treatment does not satisfy the guideline of drinking water, the groundwater shows a good water quality compared with stream water. So, the water treatment method using bank filtered groundwater can be more economical and efficient than the treatment using direct intake of stream water in the aspect of water quality. (author). 15 refs., 2 tabs., 7 figs.

  12. Method validation using weighted linear regression models for quantification of UV filters in water samples.

    Science.gov (United States)

    da Silva, Claudia Pereira; Emídio, Elissandro Soares; de Marchi, Mary Rosa Rodrigues

    2015-01-01

    This paper describes the validation of a method consisting of solid-phase extraction followed by gas chromatography-tandem mass spectrometry for the analysis of the ultraviolet (UV) filters benzophenone-3, ethylhexyl salicylate, ethylhexyl methoxycinnamate and octocrylene. The method validation criteria included evaluation of selectivity, analytical curve, trueness, precision, limits of detection and limits of quantification. The non-weighted linear regression model has traditionally been used for calibration, but it is not necessarily the optimal model in all cases. Because the assumption of homoscedasticity was not met for the analytical data in this work, a weighted least squares linear regression was used for the calibration method. The evaluated analytical parameters were satisfactory for the analytes and showed recoveries at four fortification levels between 62% and 107%, with relative standard deviations less than 14%. The detection limits ranged from 7.6 to 24.1 ng L(-1). The proposed method was used to determine the amount of UV filters in water samples from water treatment plants in Araraquara and Jau in São Paulo, Brazil. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Water Quality of Trickling Biological Periwinkle Shells Filter for ...

    African Journals Online (AJOL)

    Studies were carried on the design, efficiency and economics of trickling biological periwinkle shells filter in recirculating aquaculture systems for catfish production. The designed biofilter and other system components were constructed, assembled and commissioned for pilot catfish production. The system with the designed ...

  14. Field investigation of arsenic in ceramic pot filter-treated drinking water.

    Science.gov (United States)

    Archer, A R; Elmore, A C; Bell, E; Rozycki, C

    2011-01-01

    Ceramic pot filters (CPFs) is one of several household water treatment technologies that is used to treat drinking water in developing areas. The filters have the advantage of being able to be manufactured using primarily locally available materials and local labor. However, naturally-occurring arsenic present in the clay used to make the filters has the potential to contaminate the water in excess of the World Health Organization drinking water standard of 0.01 mg/L. A manufacturing facility in Guatemala routinely rinses filters to reduce arsenic concentrations prior to distribution to consumers. A systemic study was performed to evaluate the change in arsenic concentrations with increasing volumes of rinse water. Arsenic field kit results were compared to standard method laboratory results, and dissolved versus suspended arsenic concentrations in CPF-treated water were evaluated. The results of the study suggest that rinsing is an effective means of mitigating arsenic leached from the filters, and that even in the absence of a formal rinsing program, routine consumer use may result in the rapid decline of arsenic concentrations. More importantly, the results indicate that filter manufacturers should give strong consideration to implementing an arsenic testing program.

  15. Safe household water treatment and storage using ceramic drip filters: a randomised controlled trial in Bolivia.

    Science.gov (United States)

    Clasen, T; Brown, J; Suntura, O; Collin, S

    2004-01-01

    A randomised controlled field trial was conducted to evaluate the effectiveness of ceramic drip filters to improve the microbiological quality of drinking water in a low-income community in rural Bolivia. In four rounds of water sampling over five months, 100% of the samples were free of thermotolerant (faecal) coliforms (TTC) compared to an arithmetic mean TTC count of 1517, 406, 167 and 245 among control households which continued to use their customary sources of drinking water. The filter systems produced water that consistently met WHO drinking-water standards despite levels of turbidity that presented a challenge to other low-cost POU treatment methods. The filter systems also demonstrated an ability to maintain the high quality of the treated water against subsequent re-contamination in the home.

  16. Time-Sequential Working Wavelength-Selective Filter for Flat Autostereoscopic Displays

    Directory of Open Access Journals (Sweden)

    René de la Barré

    2017-02-01

    Full Text Available A time-sequential working, spatially-multiplexed autostereoscopic 3D display design consisting of a fast switchable RGB-color filter array and a fast color display is presented. The newly-introduced 3D display design is usable as a multi-user display, as well as a single-user system. The wavelength-selective filter barrier emits the light from a larger aperture than common autostereoscopic barrier displays with similar barrier pitch and ascent. Measurements on a demonstrator with commercial display components, simulations and computational evaluations have been carried out to describe the proposed wavelength-selective display design in static states and to show the weak spots of display filters in commercial displays. An optical modelling of wavelength-selective barriers has been used for instance to calculate the light ray distribution properties of that arrangement. In the time-sequential implementation, it is important to avoid that quick eye or eyelid movement leads to visible color artifacts. Therefore, color filter cells, switching faster than conventional LC display cells, must distribute directed light from different primaries at the same time, to create a 3D presentation. For that, electric tunable liquid crystal Fabry–Pérot color filters are presented. They switch on-off the colors red, green and blue in the millisecond regime. Their active areas consist of a sub-micrometer-thick nematic layer sandwiched between dielectric mirrors and indium tin oxide (ITO-electrodes. These cells shall switch narrowband light of red, green or blue. A barrier filter array for a high resolution, glasses-free 3D display has to be equipped with several thousand switchable filter elements having different color apertures.

  17. Re-evaluating the relationships among filtering activity, unnecessary storage, and visual working memory capacity.

    Science.gov (United States)

    Emrich, Stephen M; Busseri, Michael A

    2015-09-01

    The amount of task-irrelevant information encoded in visual working memory (VWM), referred to as unnecessary storage, has been proposed as a potential mechanism underlying individual differences in VWM capacity. In addition, a number of studies have provided evidence for additional activity that initiates the filtering process originating in the frontal cortex and basal ganglia, and is therefore a crucial step in the link between unnecessary storage and VWM capacity. Here, we re-examine data from two prominent studies that identified unnecessary storage activity as a predictor of VWM capacity by directly testing the implied path model linking filtering-related activity, unnecessary storage, and VWM capacity. Across both studies, we found that unnecessary storage was not a significant predictor of individual differences in VWM capacity once activity associated with filtering was accounted for; instead, activity associated with filtering better explained variation in VWM capacity. These findings suggest that unnecessary storage is not a limiting factor in VWM performance, whereas neural activity associated with filtering may play a more central role in determining VWM performance that goes beyond preventing unnecessary storage.

  18. Facile Preparation of Nanostructured, Superhydrophobic Filter Paper for Efficient Water/Oil Separation.

    Directory of Open Access Journals (Sweden)

    Jianhua Wang

    Full Text Available In this paper, we present a facile and cost-effective method to obtain superhydrophobic filter paper and demonstrate its application for efficient water/oil separation. By coupling structurally distinct organosilane precursors (e.g., octadecyltrichlorosilane and methyltrichlorosilane to paper fibers under controlled reaction conditions, we have formulated a simple, inexpensive, and efficient protocol to achieve a desirable superhydrophobic and superoleophilic surface on conventional filter paper. The silanized superhydrophobic filter paper showed nanostructured morphology and demonstrated great separation efficiency (up to 99.4% for water/oil mixtures. The modified filter paper is stable in both aqueous solutions and organic solvents, and can be reused multiple times. The present study shows that our newly developed binary silanization is a promising method of modifying cellulose-based materials for practical applications, in particular the treatment of industrial waste water and ecosystem recovery.

  19. Preparation of affordable and multifunctional clay-based ceramic filter matrix for treatment of drinking water.

    Science.gov (United States)

    Shivaraju, H Puttaiah; Egumbo, Henok; Madhusudan, P; Anil Kumar, K M; Midhun, G

    2018-02-01

    Affordable clay-based ceramic filters with multifunctional properties were prepared using low-cost and active ingredients. The characterization results clearly revealed well crystallinity, structural elucidation, extensive porosity, higher surface area, higher stability, and durability which apparently enhance the treatment efficiency. The filtration rates of ceramic filter were evaluated under gravity and the results obtained were compared with a typical gravity slow sand filter (GSSF). All ceramic filters showed significant filtration rates of about 50-180 m/h, which is comparatively higher than the typical GSSF. Further, purification efficiency of clay-based ceramic filters was evaluated by considering important drinking water parameters and contaminants. A significant removal potential was achieved by the clay-based ceramic filter with 25% and 30% activated carbon along with active agents. Desired drinking water quality parameters were achieved by potential removal of nitrite (98.5%), nitrate (80.5%), total dissolved solids (62%), total hardness (55%), total organic pollutants (89%), and pathogenic microorganisms (100%) using ceramic filters within a short duration. The remarkable purification and disinfection efficiencies were attributed to the extensive porosity (0.202 cm 3  g -1 ), surface area (124.61 m 2  g -1 ), stability, and presence of active nanoparticles such as Cu, TiO 2 , and Ag within the porous matrix of the ceramic filter.

  20. Preventing diarrhoea with household ceramic water filters: assessment of a pilot project in Bolivia.

    Science.gov (United States)

    Clasen, Thomas F; Brown, Joseph; Collin, Simon M

    2006-06-01

    In an attempt to prevent diarrhoea in a rural community in central Bolivia, an international non-governmental organization implemented a pilot project to improve drinking water quality using gravity-fed, household-based, ceramic water filters. We assessed the performance of the filters by conducting a five-month randomized controlled trial among all 60 households in the pilot community. Water filters eliminated thermotolerant (faecal) coliforms from almost all intervention households and significantly reduced turbidity, thereby improving water aesthetics. Most importantly, the filters were associated with a 45.3% reduction in prevalence of diarrhoea among the study population (p = 0.02). After adjustment for household clustering and repeated episodes in individuals and controlling for age and baseline diarrhoea, prevalence of diarrhoea among the intervention group was 51% lower than controls, though the protective effect was only borderline significant (OR 0.49, 95% CI: 0.24, 1.01; p = 0.05). A follow-up survey conducted approximately 9 months after deployment of the filters found 67% being used regularly, 13% being used intermittently, and 21% not in use. Water samples from all regularly used filters were free of thermotolerant coliforms.

  1. The effects of two types of sleep deprivation on visual working memory capacity and filtering efficiency.

    Directory of Open Access Journals (Sweden)

    Sean P A Drummond

    Full Text Available Sleep deprivation has adverse consequences for a variety of cognitive functions. The exact effects of sleep deprivation, though, are dependent upon the cognitive process examined. Within working memory, for example, some component processes are more vulnerable to sleep deprivation than others. Additionally, the differential impacts on cognition of different types of sleep deprivation have not been well studied. The aim of this study was to examine the effects of one night of total sleep deprivation and 4 nights of partial sleep deprivation (4 hours in bed/night on two components of visual working memory: capacity and filtering efficiency. Forty-four healthy young adults were randomly assigned to one of the two sleep deprivation conditions. All participants were studied: 1 in a well-rested condition (following 6 nights of 9 hours in bed/night; and 2 following sleep deprivation, in a counter-balanced order. Visual working memory testing consisted of two related tasks. The first measured visual working memory capacity and the second measured the ability to ignore distractor stimuli in a visual scene (filtering efficiency. Results showed neither type of sleep deprivation reduced visual working memory capacity. Partial sleep deprivation also generally did not change filtering efficiency. Total sleep deprivation, on the other hand, did impair performance in the filtering task. These results suggest components of visual working memory are differentially vulnerable to the effects of sleep deprivation, and different types of sleep deprivation impact visual working memory to different degrees. Such findings have implications for operational settings where individuals may need to perform with inadequate sleep and whose jobs involve receiving an array of visual information and discriminating the relevant from the irrelevant prior to making decisions or taking actions (e.g., baggage screeners, air traffic controllers, military personnel, health care

  2. The effects of two types of sleep deprivation on visual working memory capacity and filtering efficiency.

    Science.gov (United States)

    Drummond, Sean P A; Anderson, Dane E; Straus, Laura D; Vogel, Edward K; Perez, Veronica B

    2012-01-01

    Sleep deprivation has adverse consequences for a variety of cognitive functions. The exact effects of sleep deprivation, though, are dependent upon the cognitive process examined. Within working memory, for example, some component processes are more vulnerable to sleep deprivation than others. Additionally, the differential impacts on cognition of different types of sleep deprivation have not been well studied. The aim of this study was to examine the effects of one night of total sleep deprivation and 4 nights of partial sleep deprivation (4 hours in bed/night) on two components of visual working memory: capacity and filtering efficiency. Forty-four healthy young adults were randomly assigned to one of the two sleep deprivation conditions. All participants were studied: 1) in a well-rested condition (following 6 nights of 9 hours in bed/night); and 2) following sleep deprivation, in a counter-balanced order. Visual working memory testing consisted of two related tasks. The first measured visual working memory capacity and the second measured the ability to ignore distractor stimuli in a visual scene (filtering efficiency). Results showed neither type of sleep deprivation reduced visual working memory capacity. Partial sleep deprivation also generally did not change filtering efficiency. Total sleep deprivation, on the other hand, did impair performance in the filtering task. These results suggest components of visual working memory are differentially vulnerable to the effects of sleep deprivation, and different types of sleep deprivation impact visual working memory to different degrees. Such findings have implications for operational settings where individuals may need to perform with inadequate sleep and whose jobs involve receiving an array of visual information and discriminating the relevant from the irrelevant prior to making decisions or taking actions (e.g., baggage screeners, air traffic controllers, military personnel, health care providers).

  3. Microbial pesticide removal in rapid sand filters for drinking water treatment – Potential and kinetics

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    2014-01-01

    Filter sand samples, taken from aerobic rapid sand filters used for treating groundwater at three Danish waterworks, were investigated for their pesticide removal potential and to assess the kinetics of the removal process. Microcosms were set up with filter sand, treated water, and the pesticides...... or metabolites mecoprop (MCPP), bentazone, glyphosate and p-nitrophenol were applied in initial concentrations of 0.03–2.4 μg/L. In all the investigated waterworks the concentration of pesticides in the water decreased – MCPP decreased to 42–85%, bentazone to 15–35%, glyphosate to 7–14% and p-nitrophenol 1....../L) increased from 0.21%/g filter sand to 0.75%/g filter sand, when oxygen availability was increased from 0.28 mg O2/g filter sand to 1.09 mg O2/g filter sand. Bentazone was initially cleaved in the removal process. A metabolite, which contained the carbonyl group, was removed rapidly from the water phase...

  4. Filterability of corrosion products formed between carbon steel and water. Influence of temperature and oxygen content

    International Nuclear Information System (INIS)

    Kelen, T.; Falk, I.

    1975-09-01

    A laboratory investigation has been made for the purpose of studying the influence of temperature and oxygen content on the filterability of corrosion products formed between carbon-steel and water. The experiments were performed in a high temperature loop where the water is initially heated in a pre-heater, then cooled and finally filtered. The corrosion products were transferred to thewater from a carbon-steel surface that had previously been neutron activated and the amount of iron present was determined from measurements of the γ-radiation emitted by Fe-59. Filterability was then computed as the ratio between the total amount of iron in the water phase and the amount of iron retained on the filter. The investigation covers a series of experiments at filtering temperatures of 20, 90 and 160 dec G, pre-heater temperatures up to 300 deg C and oxygen contents of 10 and 300 ppb O 2 . In addition the extent of iron deposition in the pre-heater and heat regulator has been determined after each series of experiments. Filterability exhibited a pronounced dependence upon both the filter and pre-heater temperatures and also upon the oxygen content. Among the conclusions to which the results lead is the observation that a strict comparison of filterability values for the fraction of corrosion products in cooled water samples is impossible when these are taken from 1) different sections of a high temperature system 2) a single sampling point while the system is being run up 3) two separate systems (e.g. steam boilers) operated at different temperatures 4) two separate systems operated at different oxygen contents. It accordingly appears advizable to restrict the use of cold-filtered samples from conventional steam-raising plants to the comparison of values relating to a single sampling point under constant operating conditions. (author)

  5. Evaluation of the MF/UF Performance for the Reuse of Sand Filter Backwash Water from Drinking Water Treatment Plants

    Directory of Open Access Journals (Sweden)

    Neda Shirzadi

    2015-05-01

    Full Text Available The aim of this study was to investigate the application of micro-filtration and ultra-filtration membrane systems in order to improve the physical and microbial quality and the reuse of backwash water from the sand filter units in water treatment plants. The backwash water from filters makes up for 3 to 5 percent of the total water treated, which is disposed in most WTPs. However, the treatment and reuse of the backwash water is more admissible from technical and economic viewpoints, especially in view of the present water scarcity. For the purposes of this study, use was made of membrane modules of micro- and ultra-filters on a pilot scale. The micro-filter employed consisted of a polypropylene membrane module with a porosity of 1 micron in size and a fiberglass module with a porosity of 5 microns. The ultra-filter was made of PVC hollow fiber with a molecular weight of 100,000 Dalton. In order to feed the two pilots, backwash water from a sand filter was collected from one of the WTPs in Tehran. After samples were taken from the backwash water, the physical and microbial removal efficiency was periodically evaluated based on the standard method and the micro-filtration, ultra-filtration, and combined MF/UF processes were compared with respect to their performance. The results indicate that the combined MF/UF process is able to decrease turbidity, MPN, COD, TSS, and Fe with efficiency values of 99.9, 100, 61.5, 99.9 and 98.8 percent, respectively. Overall, the findings confirmed the technical capabilities of this method for the recovery and reuse of the effluent produced in the backwashing mechanism of sand filters in WTPs.

  6. Effects of dynamic operating conditions on nitrification in biological rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Boe-Hansen, Rasmus; Musovic, Sanin

    2014-01-01

    Biological rapid sand filters are often used to remove ammonium from groundwater for drinking water supply. They often operate under dynamic substrate and hydraulic loading conditions, which can lead to increased levels of ammonium and nitrite in the effluent. To determine the maximum nitrification...... operating conditions. The ammonium removal rate of the filter was determined by the ammonium loading rate, but was independent of both the flow and influent ammonium concentration individually. Ammonia-oxidizing bacteria and archaea were almost equally abundant in the filter. Both ammonium removal...... rates and safe operating windows of rapid sand filters, a pilot scale rapid sand filter was used to test short-term increased ammonium loads, set by varying either influent ammonium concentrations or hydraulic loading rates. Ammonium and iron (flock) removal were consistent between the pilot...

  7. Evaluating the sustainability of ceramic filters for point-of-use drinking water treatment.

    Science.gov (United States)

    Ren, Dianjun; Colosi, Lisa M; Smith, James A

    2013-10-01

    This study evaluates the social, economic, and environmental sustainability of ceramic filters impregnated with silver nanoparticles for point-of-use (POU) drinking water treatment in developing countries. The functional unit for this analysis was the amount of water consumed by a typical household over ten years (37,960 L), as delivered by either the POU technology or a centralized water treatment and distribution system. Results indicate that the ceramic filters are 3-6 times more cost-effective than the centralized water system for reduction of waterborne diarrheal illness among the general population and children under five. The ceramic filters also exhibit better environmental performance for four of five evaluated life cycle impacts: energy use, water use, global warming potential, and particulate matter emissions (PM10). For smog formation potential, the centralized system is preferable to the ceramic filter POU technology. This convergence of social, economic, and environmental criteria offers clear indication that the ceramic filter POU technology is a more sustainable choice for drinking water treatment in developing countries than the centralized treatment systems that have been widely adopted in industrialized countries.

  8. Controlled laboratory experiments and modeling of vegetative filter strips with shallow water tables

    Science.gov (United States)

    Fox, Garey A.; Muñoz-Carpena, Rafael; Purvis, Rebecca A.

    2018-01-01

    Natural or planted vegetation at the edge of fields or adjacent to streams, also known as vegetative filter strips (VFS), are commonly used as an environmental mitigation practice for runoff pollution and agrochemical spray drift. The VFS position in lowlands near water bodies often implies the presence of a seasonal shallow water table (WT). In spite of its potential importance, there is limited experimental work that systematically studies the effect of shallow WTs on VFS efficacy. Previous research recently coupled a new physically based algorithm describing infiltration into soils bounded by a water table into the VFS numerical overland flow and transport model, VFSMOD, to simulate VFS dynamics under shallow WT conditions. In this study, we tested the performance of the model against laboratory mesoscale data under controlled conditions. A laboratory soil box (1.0 m wide, 2.0 m long, and 0.7 m deep) was used to simulate a VFS and quantify the influence of shallow WTs on runoff. Experiments included planted Bermuda grass on repacked silt loam and sandy loam soils. A series of experiments were performed including a free drainage case (no WT) and a static shallow water table (0.3-0.4 m below ground surface). For each soil type, this research first calibrated VFSMOD to the observed outflow hydrograph for the free drainage experiments to parameterize the soil hydraulic and vegetation parameters, and then evaluated the model based on outflow hydrographs for the shallow WT experiments. This research used several statistical metrics and a new approach based on hypothesis testing of the Nash-Sutcliffe model efficiency coefficient (NSE) to evaluate model performance. The new VFSMOD routines successfully simulated the outflow hydrographs under both free drainage and shallow WT conditions. Statistical metrics considered the model performance valid with greater than 99.5% probability across all scenarios. This research also simulated the shallow water table experiments with

  9. The protective role of ceramic filters against natural radioactivity of water

    International Nuclear Information System (INIS)

    Domanski, T.; Bakir, Y.Y.Y.; El-Zenki, S.; Bem, H.

    1992-01-01

    The paper presents results of measurements of the natural radioactivity of tap water where samples were taken in front of, and behind the ceramic filter commonly used in houses for the purification of tap water. Altogether, 289 samples were taken, processed and measured during 1985-1986 in Kuwait. Results reveal the fact that ceramic filters reduce substantially the natural radioactivity in water (the 'gross' alpha activity reduced by the factor 2.18 ± 18%; the 'gross' beta by 1.53 ± 1.6%. (author)

  10. More than a filter: Feature-based attention regulates the distribution of visual working memory resources.

    Science.gov (United States)

    Dube, Blaire; Emrich, Stephen M; Al-Aidroos, Naseem

    2017-10-01

    Across 2 experiments we revisited the filter account of how feature-based attention regulates visual working memory (VWM). Originally drawing from discrete-capacity ("slot") models, the filter account proposes that attention operates like the "bouncer in the brain," preventing distracting information from being encoded so that VWM resources are reserved for relevant information. Given recent challenges to the assumptions of discrete-capacity models, we investigated whether feature-based attention plays a broader role in regulating memory. Both experiments used partial report tasks in which participants memorized the colors of circle and square stimuli, and we provided a feature-based goal by manipulating the likelihood that 1 shape would be probed over the other across a range of probabilities. By decomposing participants' responses using mixture and variable-precision models, we estimated the contributions of guesses, nontarget responses, and imprecise memory representations to their errors. Consistent with the filter account, participants were less likely to guess when the probed memory item matched the feature-based goal. Interestingly, this effect varied with goal strength, even across high probabilities where goal-matching information should always be prioritized, demonstrating strategic control over filter strength. Beyond this effect of attention on which stimuli were encoded, we also observed effects on how they were encoded: Estimates of both memory precision and nontarget errors varied continuously with feature-based attention. The results offer support for an extension to the filter account, where feature-based attention dynamically regulates the distribution of resources within working memory so that the most relevant items are encoded with the greatest precision. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  11. Vertical flow soil filter for the elimination of micro pollutants from storm and waste water

    DEFF Research Database (Denmark)

    Janzen, Niklas; Banzhaf, Stefan; Scheytt, Traugott

    2009-01-01

    A technical scale activated soil filter has been used to study the elimination rates of diverse environmentally relevant micro pollutants from storm and waste water. The filter was made of layers of peat, sand and gravel. The upper (organic) layer was planted with reed (phragmites australis......) to prevent clogging and was spiked with activated sludge to enhance microbial biomass and biodegradation potential. Compounds used as UV filters, antioxidants or plasticizers, namely 4-methylbenzylidene camphor (4-MBC), benzophenone-3 (BP-3), butylated hydroxytoluene (BHT), N-butylbenzenesulfonamide (NBBS...

  12. Impact of temperature on nitrification in biological activated carbon (BAC) filters used for drinking water treatment.

    Science.gov (United States)

    Andersson, A; Laurent, P; Kihn, A; Prévost, M; Servais, P

    2001-08-01

    The impact of temperature on nitrification in biological granular activated carbon (GAC) filters was evaluated in order to improve the understanding of the nitrification process in drinking water treatment. The study was conducted in a northern climate where very cold water temperatures (below 2 degrees C) prevail for extended periods and rapid shifts of temperature are frequent in the spring and fall. Ammonia removals were monitored and the fixed nitrifying biomass was measured using a method of potential nitrifying activity. The impact of temperature was evaluated on two different filter media: an opened superstructure wood-based activated carbon and a closed superstructure activated carbon-based on bituminous coal. The study was conducted at two levels: pilot scale (first-stage filters) and full-scale (second-stage filters) and the results indicate a strong temperature impact on nitrification activity. Ammonia removal capacities ranged from 40 to 90% in pilot filters, at temperatures above 10 degrees C, while more than 90% ammonia was removed in the full-scale filters for the same temperature range. At moderate temperatures (4-10 degrees C), the first stage pilot filters removed 10-40% of incoming ammonia for both media (opened and closed superstructure). In the full-scale filters, a difference between the two media in nitrification performances was observed at moderate temperatures: the ammonia removal rate in the opened superstructure support (more than 90%) was higher than in the closed superstructure support (45%). At low temperatures (below 4 degrees C) both media performed poorly. Ammonia removal capacities were below 30% in both pilot- and full-scale filters.

  13. Field application of farmstead runoff to vegetated filter strips: surface and subsurface water quality assessment.

    Science.gov (United States)

    Larson, Rebecca A; Safferman, Steven I

    2012-01-01

    Farmstead runoff poses significant environmental impacts to ground and surface waters. Three vegetated filter strips were assessed for the treatment of dairy farmstead runoff at the soil surface and subsurface at 0.3- or 0. 46-m and 0. 76-m depths for numerous storm events. A medium-sized Michigan dairy was retrofitted with two filter strips on sandy loam soil and a third filter strip was implemented on a small Michigan dairy with sandy soil to collect and treat runoff from feed storage, manure storage, and other impervious farmstead areas. All filter strips were able to eliminate surface runoff via infiltration for all storm events over the duration of the study, eliminating pollutant contributions to surface water. Subsurface effluent was monitored to determine the contributing groundwater concentrations of numerous pollutants including chemical oxygen demand (COD), metals, and nitrates. Subsurface samples have an average reduction of COD concentrations of 20, 11, and 85% for the medium dairy Filter Strip 1 (FS1), medium dairy Filter Strip 2 (FS2), and the small Michigan dairy respectively, resulting in average subsurface concentrations of 355, 3960, and 718 mg L COD. Similar reductions were noted for ammonia and total Kjeldahl nitrogen (TKN) in the subsurface effluent. The small Michigan dairy was able to reduce the pollutant leachate concentrations of COD, TKN, and ammonia over a range of influent concentrations. Increased influent concentrations in the medium Michigan dairy filter strips resulted in an increase in COD, TKN, and ammonia concentrations in the leachate. Manganese was leached from the native soils at all filter strips as evidenced by the increase in manganese concentrations in the leachate. Nitrate concentrations were above standard drinking water limits (10 mg L), averaging subsurface concentrations of 11, 45, and 25 mg L NO-N for FS1, FS2, and the small Michigan dairy, respectively. Copyright © by the American Society of Agronomy, Crop Science

  14. Use of remotely reporting electronic sensors for assessing use of water filters and cookstoves in Rwanda.

    Science.gov (United States)

    Thomas, Evan A; Barstow, Christina K; Rosa, Ghislaine; Majorin, Fiona; Clasen, Thomas

    2013-01-01

    Remotely reporting electronic sensors offer the potential to reduce bias in monitoring use of environmental health interventions. In the context of a five-month randomized controlled trial of household water filters and improved cookstoves in rural Rwanda, we collected data from intervention households on product compliance using (i) monthly surveys and direct observations by community health workers and environmental health officers, and (ii) sensor-equipped filters and cookstoves deployed for about two weeks in each household. The adoption rate interpreted by the sensors varied from the household reporting: 90.5% of households reported primarily using the intervention stove, while the sensors interpreted 73.2% use, and 96.5% of households reported using the intervention filter regularly, while the sensors interpreted no more than 90.2%. The sensor-collected data estimated use to be lower than conventionally collected data both for water filters (approximately 36% less water volume per day) and cookstoves (approximately 40% fewer uses per week). An evaluation of intrahousehold consistency in use suggests that households are not using their filters or stoves on an exclusive basis, and may be both drinking untreated water at times and using other stoves ("stove-stacking"). These results provide additional evidence that surveys and direct observation may exaggerate compliance with household-based environmental interventions.

  15. Batch Test Screening of Industrial Product/Byproduct Filter Materials for Agricultural Drainage Water Treatment

    Directory of Open Access Journals (Sweden)

    Barry J. Allred

    2017-10-01

    Full Text Available Filter treatment may be a viable means for removing the nitrate (NO3−, phosphate (PO43−, and pesticides discharged with agricultural drainage waters that cause adverse environmental impacts within the U.S. on local, regional, and national scales. Laboratory batch test screening for agricultural drainage water treatment potential was conducted on 58 industrial product/byproduct filter materials grouped into six categories: (1 high carbon content media; (2 high iron content media; (3 high aluminum content media; (4 surfactant modified clay/zeolite; (5 coal combustion residuals; and (6 spent foundry sands. Based on a percent contaminant removal criteria of 75% or greater, seven industrial products/byproducts were found to meet this standard for NO3− alone, 44 met this standard for PO43−, and 25 met this standard for the chlorinated triazine herbicide, atrazine. Using a 50% or greater contaminant removal criteria, five of the industrial product/byproduct filter materials exhibited potential for removing NO3−, PO43−, and atrazine together; eight showed capability for combined NO3− and PO43− removal; 21 showed capability for combined PO43− and atrazine removal; and nine showed capability for combined NO3− and atrazine removal. The results of this study delineated some potential industrial product/byproduct filter materials for drainage water treatment; however, a complete feasibility evaluation for drainage water treatment of any of these filter materials will require much more extensive testing.

  16. performance of water filters towards the removal of selected

    African Journals Online (AJOL)

    Morohani Merinyo

    sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% ... associated diseases in developing countries ... The main drinking water risks in developing ... Tanzania Demographic and Health Survey.

  17. Initial testing of electrospun nanofibre filters in water filtration ...

    African Journals Online (AJOL)

    2009-11-17

    Nov 17, 2009 ... for water filtration applications, but that further improvements are necessary before these membranes can be ... power supply, and a grounded collector. .... nanofibres so that the pore size increases and bacteria leak through ...

  18. Development of improved low-cost ceramic water filters for viral removal in the Haitian context

    OpenAIRE

    Guerrero Latorre, Laura; Rusiñol Arantegui, Marta; Hundesa Gonfa, Ayalkibet; Garcia Vallès, Maite; Martínez Manent, Salvador; Joseph, Osnick; Bofill Mas, Silvia; Gironès Llop, Rosina

    2015-01-01

    Household-based water treatment (HWT) is increasingly being promoted to improve water quality and, therefore, health status in low-income countries. Ceramic water filters (CWFs) are used in many regions as sustainable HWT and have been proven to meet World Health Organization (WHO) microbiological performance targets for bacterial removal (24 log); however, the described viral removal efficiencies are insufficient to significantly reduce the associated risk of viral infection. With the object...

  19. Effectiveness of ceramic filters in capturing Giardia duodenalis cysts in experimentally contaminated water

    Directory of Open Access Journals (Sweden)

    Larissa Imaculada da Costa Sobrinho

    2016-04-01

    Full Text Available Giardia duodenalis is the main water-transmitted protozoan in developing countries. This study evaluated the effectiveness of ceramic filters in capturing G. duodenalis cysts and verified the porosity size needed to remove cysts from contaminated water. The study was conducted in the Laboratory of Parasitology at the University of Taubaté, where each filter unit was made by joining two Pet gallons, latex hose and a ceramic filter. Two porosity sizes were selected: 0.5-1.0 μm and 5-15 μm with or without activated carbon, and the assays were run in triplicate. Approximately 60 μL (53 cysts of G. duodenalis cysts were placed in 2 liters of distilled water. After the preparation of the contaminated water, this solution was run through the filter until the completely filtered. Afterwards, the filtrate was processed according to the methodology described by De Faria (2006, in order to concentrate parasitic elements. The results were statistically evaluated using ANOVA and Tukey tests, showing that the 0.5- 1,0 μm porosity filter candles (with and without activated carbon were able to retain 100% of cysts of G. duodenalis. This is a result significantly superior to the results obtained in the control group (p<0.05. On the other hand, for the candles with porosity of 5 15 μm, total retention occurred only in candles with activated carbon. Based upon our results, it can be concluded that, in candles with both porosity sizes with activated carbon, all filters showed a satisfactory efficacy for filtration of G. duodenalis cysts.

  20. Bowtie filter and water calibration in the improvement of cone beam CT image quality

    International Nuclear Information System (INIS)

    Li Minghui; Dai Jianrong; Zhang Ke

    2010-01-01

    Objective: To evaluate the improvement of cone beam CT (CBCT) image quality by using bewtie filter (F 1 ) and water calibration. Methods: First the multi-level gain calibration of the detector panel with the method of Cal 2 calibration was performed, and the CT images of CATPHAN503 with F 0 and bowtie filter were collected, respectively. Then the detector panel using water calibration kit was calibrated, and images were acquired again. Finally, the change of image quality after using F 1 and (or) water calibration method was observed. The observed indexes included low contrast visibility, spatial uniformity, ring artifact, spatial resolution and geometric accuracy. Results: Comparing with the traditional combination of F 0 filter and Cal 2 calibration, the combination of bowtie filter F 1 and water calibration improves low contrast visibility by 13.71%, and spatial uniformity by 54. 42%. Water calibration removes ring artifacts effectively. However, none of them improves spatial resolution and geometric accuracy. Conclusions: The combination of F 1 and water calibration improves CBCT image quality effectively. This improvement is aid to the registration of CBCT images and localization images. (authors)

  1. Optimization of band-pass filtering parameters of a Raman lidar detecting atmospheric water vapor

    International Nuclear Information System (INIS)

    Cao, Kai-Fa; Hu, Shun-Xing; Wang, Ying-jian

    2012-01-01

    It is very important for daytime Raman lidar measurement of water vapor to determine the parameters of a band-pass filter, which are pertinent to the lidar signal to noise ratio (SNR). The simulated annealing (SA) algorithm method has an advantage in finding the extremum of a certain cost function. In this paper, the Raman spectrum of water vapor is simulated and then a first realization of a simulated annealing algorithm in the optimization of a band-pass filter of a Raman lidar system designed to detect daytime water vapor is presented. The simulated results indicate that the narrow band-pass filter has higher SNR than the wide filter does but there would be an increase in the temperature sensitivity of a narrowband Raman water vapor lidar in the upper troposphere. The numerical simulation indicates that the magnitude of the temperature dependent effect can reach 3.5% or more for narrow band-pass Raman water vapor measurements so it is necessary to consider a new water vapor Raman lidar equation that permits the temperature sensitivity of these equations to be confined to a single term. (paper)

  2. Designing metallic iron based water filters: Light from methylene blue discoloration.

    Science.gov (United States)

    Btatkeu-K, B D; Tchatchueng, J B; Noubactep, C; Caré, S

    2016-01-15

    Available water filtration systems containing metallic iron (Fe(0) filters) are pragmatically designed. There is a lack of sound design criteria to exploit the full potential of Fe(0) filters. A science-based design relies on valuable information on processes within a Fe(0) filter, including chemical reactions, hydrodynamics and their relation to the performance of the filter. The aim of this study was to establish a simple method to evaluate the initial performance of Fe(0) filters. The differential adsorptive affinity of methylene blue (MB) onto sand and iron oxide is exploited to characterize the evolution of a Fe(0)/sand system using the pure sand system as operational reference. Five systems were investigated for more than 70 days: pure sand, pure Fe(0), Fe(0)/sand, Fe(0)/pumice and Fe(0)/sand/pumice. Individual systems were characterized by the extent of changes in pH value, iron breakthrough, MB breakthrough and hydraulic conductivity. Results showed that for MB discoloration (i) pure sand was the most efficient system, (ii) hybrid systems were more sustainable than the pure Fe(0) system, and (iii) the pores of used pumice are poorly interconnected. Characterizing the initial reactivity of Fe(0) filters using MB discoloration has introduced a powerful tool for the exploration of various aspects of filter design. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Filter Membrane Effects on Water-Extractable Phosphorus Concentrations from Soil.

    Science.gov (United States)

    Norby, Jessica; Strawn, Daniel; Brooks, Erin

    2018-03-01

    To accurately assess P concentrations in soil extracts, standard laboratory practices for monitoring P concentrations are needed. Water-extractable P is a common analytical test to determine P availability for leaching from soils, and it is used to determine best management practices. Most P analytical tests require filtration through a filter membrane with 0.45-μm pore size to distinguish between particulate and dissolved P species. However, filter membrane type is rarely specified in method protocols, and many different types of membranes are available. In this study, three common filter membrane materials (polyether sulfone, nylon, and nitrocellulose), all with 0.45-μm pore sizes, were tested for analytical differences in total P concentrations and dissolved reactive P (DRP) concentrations in water extracts from six soils sampled from two regions. Three of the extracts from the six soil samples had different total P concentrations for all three membrane types. The other three soil extracts had significantly different total P results from at least one filter membrane type. Total P concentration differences were as great as 35%. The DRP concentrations in the extracts were dependent on filter type in five of the six soil types. Results from this research show that filter membrane type is an important parameter that affects concentrations of total P and DRP from soil extracts. Thus, membrane type should be specified in soil extraction protocols. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Depth investigation of rapid sand filters for drinking water production reveals strong stratification in nitrification biokinetic behavior

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Albrechtsen, Hans-Jørgen

    2016-01-01

    The biokinetic behavior of NH4 + removal was investigated at different depths of a rapid sand filter treating groundwater for drinking water preparation. Filter materials from the top, middle and bottom layers of a full-scale filter were exposed to various controlled NH4 + loadings in a continuous...

  5. Identification and simulation for steam generator water level based on Kalman Filter

    International Nuclear Information System (INIS)

    Deng Chen; Zhang Qinshun

    2008-01-01

    In order to effectively control the water level of the steam generator (SG), this paper has set about the state-observer theory in modern control and put forward a method to detect the 'false water level' based on Kalman Filter. Kalman Filter is a efficient tool to estimate state-variable by measured value including noise. For heavy measurement noise of steam flow, constructing a 'false water level' observer by Kalman Filter could availably obtain state variable of 'false water level'. The simulation computing for the dynamics characteristic of nuclear SG water level process under several typically running power was implemented by employing the simulation model. The result shows that the simulation model accurately identifies the 'false water level' produced in the reverse thermal-dynamic effects of nuclear SG water level process. The simulation model can realize the precise analysis of dynamics characteristic for the nuclear SG water level process. It can provide a kind of new ideas for the 'false water level' detecting of SG. (authors)

  6. Pressurized water reactor monitoring. Study of detection, diagnostic and estimation (least squares and filtering) methods

    International Nuclear Information System (INIS)

    Gillet, M.

    1986-07-01

    This thesis presents a study for the surveillance of the Primary circuit water inventory of a pressurized water reactor. A reference model is developed for the development of an automatic system ensuring detection and real-time diagnostic. The methods to our application are statistical tests and adapted a pattern recognition method. The estimation of the detected anomalies is treated by the least square fit method, and by filtering. A new projected optimization method with superlinear convergence is developed in this framework, and a segmented linearization of the model is introduced, in view of a multiple filtering. 46 refs [fr

  7. A post-implementation evaluation of ceramic water filters distributed to tsunami-affected communities in Sri Lanka.

    Science.gov (United States)

    Casanova, Lisa M; Walters, Adam; Naghawatte, Ajith; Sobsey, Mark D

    2012-06-01

    Sri Lanka was devastated by the 2004 Indian Ocean tsunami. During recovery, the Red Cross distributed approximately 12,000 free ceramic water filters. This cross-sectional study was an independent post-implementation assessment of 452 households that received filters, to determine the proportion still using filters, household characteristics associated with use, and quality of household drinking water. The proportion of continued users was high (76%). The most common household water sources were taps or shallow wells. The majority (82%) of users used filtered water for drinking only. Mean filter flow rate was 1.12 L/hr (0.80 L/hr for households with taps and 0.71 for those with wells). Water quality varied by source; households using tap water had source water of high microbial quality. Filters improved water quality, reducing Escherichia coli for households (largely well users) with high levels in their source water. Households were satisfied with filters and are potentially long-term users. To promote sustained use, recovery filter distribution efforts should try to identify households at greatest long-term risk, particularly those who have not moved to safer water sources during recovery. They should be joined with long-term commitment to building supply chains and local production capacity to ensure safe water access.

  8. Microbial degradation of pesticides in rapid sand filters used for drinking water treatment

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen

    significantly with the maximum methane concentration in the raw water and did not correlate with other water quality parameters, such as the ammonium concentration. Furthermore, the connection between bentazone degradation and methane oxidation in filter sand was demonstrated by inhibition experiments, in which...... sustainable methods to remove pesticides from polluted water sources. Aeration of anaerobic groundwater, followed by biological rapid sand filtration is a widespread technology in drinking water treatment. Even though these systems are not designed for removal of trace contaminants, they have shown potential...... for microbial degradation of pesticides and their degradation products. If pesticides can be removed in rapid sand filters, it is of large commercial interest due to the importance in maintaining a simple, sustainable water treatment. To take advantage of the microbial pesticide degradation and identify...

  9. Biological drinking water treatment of anaerobic groundwater in trickling filters

    NARCIS (Netherlands)

    De Vet, W.W.J.M.

    2011-01-01

    Drinking water production from anaerobic groundwater is usually achieved by so called conventional techniques such as aeration and sand filtration. The notion conventional implies a long history and general acceptation of the application, but doesn’t necessarily mean a thorough understanding of the

  10. Initial testing of electrospun nanofibre filters in water filtration ...

    African Journals Online (AJOL)

    The aim of this study was to evaluate the use of nanofibre microfiltration membranes, spun by an innovative electrospinning technique, in water filtration applications. As such, this study bridges the gap between developments in electrospinning techniques for the production of flat-sheet membranes and the application of ...

  11. Reducing diarrhea through the use of household-based ceramic water filters: a randomized, controlled trial in rural Bolivia.

    Science.gov (United States)

    Clasen, Thomas F; Brown, Joseph; Collin, Simon; Suntura, Oscar; Cairncross, Sandy

    2004-06-01

    Ceramic water filters have been identified as one of the most promising and accessible technologies for treating water at the household level. In a six-month trial, water filters were distributed randomly to half of the 50 participating households in a rural community in Bolivia; the remaining households continued to use customary water handling practices and served as controls. In four rounds of sampling following distribution of the filters, 100% of the 96 water samples from the filter households were free of thermotolerant coliforms compared with 15.5% of the control household samples. Diarrheal disease risk for individuals in intervention households was 70% lower than for controls (95% confidence interval [CI] = 53-80%; P ceramic water filters enable low-income households to treat and maintain the microbiologic quality of their drinking water.

  12. Bottled, filtered, and tap water use in Latino and non-Latino children.

    Science.gov (United States)

    Hobson, Wendy L; Knochel, Miguel L; Byington, Carrie L; Young, Paul C; Hoff, Charles J; Buchi, Karen F

    2007-05-01

    To describe bottled, filtered, and tap water consumption and fluoride use among pediatric patients; to analyze differences between ethnic and socioeconomic groups; and to describe the frequency of physician-parent discussions regarding water consumption. Convenience sample survey. An urban public health clinic. Parents attending a public health clinic. The primary outcome measure was the prevalence of tap, filtered, and bottled water use. The secondary outcome measures were supplemental fluoride use and the percentage of patients reporting discussions of water consumption with their physician. A total of 216 parents (80.5% Latino and 19.5% non-Latino) completed the survey. Of the parents, 30.1% never drank tap water and 41.2% never gave it to their children. Latino parents were less likely than non-Latino parents to drink tap water (odds ratio, 0.26; 95% confidence interval, 0.10-0.67) and less likely to give tap water to their children (odds ratio, 0.32; 95% confidence interval, 0.15-0.70). More Latinos believed that tap water would make them sick (odds ratio, 5.63; 95% confidence interval, 2.17-14.54). Approximately 40% of children who never drank tap water were not receiving fluoride supplements. Of the lowest-income families (water to their children. Of the parents surveyed, 82.5% reported that their child's physician had never discussed the type of water they should use. Many Latino families avoid drinking tap water because they fear it causes illness. Unnecessary use of bottled and filtered water is costly and may result in adverse dental health outcomes. Physicians should provide guidance to families regarding the safety, low cost, and dental health benefits of drinking tap water.

  13. GPR image analysis to locate water leaks from buried pipes by applying variance filters

    Science.gov (United States)

    Ocaña-Levario, Silvia J.; Carreño-Alvarado, Elizabeth P.; Ayala-Cabrera, David; Izquierdo, Joaquín

    2018-05-01

    Nowadays, there is growing interest in controlling and reducing the amount of water lost through leakage in water supply systems (WSSs). Leakage is, in fact, one of the biggest problems faced by the managers of these utilities. This work addresses the problem of leakage in WSSs by using GPR (Ground Penetrating Radar) as a non-destructive method. The main objective is to identify and extract features from GPR images such as leaks and components in a controlled laboratory condition by a methodology based on second order statistical parameters and, using the obtained features, to create 3D models that allows quick visualization of components and leaks in WSSs from GPR image analysis and subsequent interpretation. This methodology has been used before in other fields and provided promising results. The results obtained with the proposed methodology are presented, analyzed, interpreted and compared with the results obtained by using a well-established multi-agent based methodology. These results show that the variance filter is capable of highlighting the characteristics of components and anomalies, in an intuitive manner, which can be identified by non-highly qualified personnel, using the 3D models we develop. This research intends to pave the way towards future intelligent detection systems that enable the automatic detection of leaks in WSSs.

  14. Social exclusion weakens storage capacity and attentional filtering ability in visual working memory.

    Science.gov (United States)

    Xu, Mengsi; Qiao, Lei; Qi, Senqing; Li, Zhiai; Diao, Liuting; Fan, Lingxia; Zhang, Lijie; Yang, Dong

    2018-01-01

    Social exclusion has been found to impair visual working memory (WM), while the underlying neural processes are currently unclear. Using two experiments, we tested whether the poor WM performance caused by exclusion was due to reduced storage capacity, impaired attentional filtering ability or both. The Cyberball game was used to manipulate social exclusion. Seventy-four female participants performed WM tasks while event-related potentials were recorded. In Experiment 1, participants were made to remember the orientations of red rectangles while ignoring salient green rectangles. Results showed that exclusion impaired the ability to filter out irrelevant items from WM, as reflected by the similar contralateral delay activity (CDA) amplitudes for one-target-one-distractor condition and two-targets condition, as well as the similar CDA amplitudes for two-targets-two-distractors condition and four-targets condition in excluded individuals. In Experiment 2, participants were asked to remember 1-5 colored squares. Results showed that exclusion reduced storage capacity, as the CDA amplitudes reached asymptote at loads of two items for exclusion group and at loads of three items for inclusion group. Together, these two experiments provided complementary evidence that WM deficits caused by social exclusion were due to reduced storage capacity and impaired attentional filtering ability. © The Author (2017). Published by Oxford University Press.

  15. Importance of copper for nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt

    When anoxic groundwater is treated to produce drinking water, ammonium is commonly removed through nitrification in rapid sand filters. Nitrification is a biological process, and is mediated by chemoautotrophic microorganisms. Ammonia oxidizing bacteria (AOB) and archaea (AOA) oxidize ammonium...... to remove ammonium to below the national drinking water quality standard of 0.05 mg NH4+/L. A better process understanding of nitrifying biofilters is needed to optimize treatment performance, remediate existing filters, and to prevent future nitrification problems. The frequent incidents of insufficient...... in the oxidation of ammonia to hydroxylamine. Thus, slow and incomplete nitrification could be caused by a lack of sufficient amounts of copper. The overall aim of this PhD project was therefore to determine whether copper supplementation could enhance nitrification in rapid sand filters with incomplete...

  16. The Challenge of Producing and Marketing Colloidal Silver Water Filters in Nepal

    Directory of Open Access Journals (Sweden)

    Anne Bogler

    2015-07-01

    Full Text Available Background: Obtaining safe drinking water can be a challenge in Nepal. By training potters and setting up production sites for Colloidal Silver Filters, several non-governmental organizations have tried to provide local people with a low-cost option for household water treatment. Out of 19 trained entrepreneurs, only four are currently producing filters. The goal of this evaluation was to find out what conditions lead to the successful continuation of the production and the reasons for failure. Methods: The evaluation of the potters was based on a Qualitative Comparative Analysis and the conditions looked at were: “Production”, “Collaboration”, “Market” and “Potter”. Results: Analysis showed that production problems and insufficient demand led to the termination of ceramic filter production and that both trouble-free production and high demand are necessary for a sustainable business.

  17. Dataset on the cost estimation for spent filter backwash water (SFBW treatment

    Directory of Open Access Journals (Sweden)

    Afshin Ebrahimi

    2017-12-01

    Full Text Available The dataset presented in this article are related to the research article entitled “Hybrid coagulation-UF processes for spent filter backwash water treatment: a comparison studies for PAFCl and FeCl3 as a pre-treatment” (Ebrahimi et al., 2017 [1]. This article reports the cost estimation for treating produced spent filter backwash water (SFBW during water treatment in Isfahan- Iran by various methods including primary sedimentation, coagulation & flocculation, second clarification, ultra filtration (UF and recirculation of settled SFBW to water treatment plant (WTP entrance. Coagulation conducted by PAFCl and FeCl3 as pre polymerized and traditional coagulants. Cost estimation showed that contrary to expectations, the recirculation of settled SFBW to WTP entrance is more expensive than other method and it costs about $ 37,814,817.6. Versus the cheapest option related to separate primary sedimentation, coagulation & flocculation in WTP. This option cost about $ 4,757,200 and $ 950,213 when FeCl3 and PAFCl used as coagulant, respectively. Keywords: Spent filter backwash water, Water treatment, Coat estimation, Water reuse

  18. Environmental occurrence and ecological risk assessment of organic UV filters in marine organisms from Hong Kong coastal waters.

    Science.gov (United States)

    Sang, Ziye; Leung, Kelvin Sze-Yin

    2016-10-01

    Organic UV filters, now considered to be emerging contaminants in aquatic ecosystems, are being intensively tracked in environmental waters worldwide. However, their environmental fate and impact of these contaminants on marine organisms remains largely unknown, especially in Asia. This work elucidates the occurrence and the ecological risks of seven UV filters detected in farmed fish, wild mussels and some other wild organisms collected from local mariculture farms in Hong Kong. For all of the organisms, ethylhexyl methoxycinnamate (EHMC) and octyl dimethyl p-aminobenzoic acid (OD-PABA) were the predominant contaminants with the highest concentrations up to 51.3 and 24.1ng/g (dw), respectively; lower levels were found for benzophenone-8 (BP-8), octocrylene (OC) and benzophenone-3 (BP-3) from filters indicated a positive correlation between their measured concentrations and the anthropogenic activities responsible for their direct emission. The ecological risk assessment specific to the marine aquatic environment was carried out. The risk quotient (RQ) values of EHMC and BP-3 were calculated as 3.29 and 2.60, respectively, indicating these two UV filters may pose significant risks to the marine aquatic environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Microbial activity in granular activated carbon filters in drinking water treatment

    NARCIS (Netherlands)

    Knezev, A.

    2015-01-01

    The investigations described are carried out to analyse the microbiological processes in relation to the GAC characteristics and the removal of natural organic matter (NOM) in Granular Activated Carbon filters (GACFs) in water treatment. The main goal of the study was to obtain a qualitative

  20. Low-cost domestic water filter: The case for a process-based ...

    African Journals Online (AJOL)

    Low-cost domestic water filter: The case for a process-based approach for the development of a rural technology product. ... Since the project aims at technology transfer to the rural poor for generating rural livelihoods, appropriate financial models and the general sustainability issues for such an activity are briefly discussed ...

  1. Cationic polymers in water treatment: Part 2: Filterability of CPE-formed suspension

    Czech Academy of Sciences Publication Activity Database

    Polášek, P.; Mutl, Silvestr

    2002-01-01

    Roč. 28, č. 1 (2002), s. 83-88 ISSN 0378-4738 R&D Projects: GA AV ČR KSK2067107 Institutional research plan: CEZ:AV0Z2060917 Keywords : cationic polymers * water treatment * filterability of CPE-formed suspension Subject RIV: BK - Fluid Dynamics Impact factor: 0.481, year: 2002

  2. Noninvasive mapping of water diffusional exchange in the human brain using filter-exchange imaging.

    Science.gov (United States)

    Nilsson, Markus; Lätt, Jimmy; van Westen, Danielle; Brockstedt, Sara; Lasič, Samo; Ståhlberg, Freddy; Topgaard, Daniel

    2013-06-01

    We present the first in vivo application of the filter-exchange imaging protocol for diffusion MRI. The protocol allows noninvasive mapping of the rate of water exchange between microenvironments with different self-diffusivities, such as the intracellular and extracellular spaces in tissue. Since diffusional water exchange across the cell membrane is a fundamental process in human physiology and pathophysiology, clinically feasible and noninvasive imaging of the water exchange rate would offer new means to diagnose disease and monitor treatment response in conditions such as cancer and edema. The in vivo use of filter-exchange imaging was demonstrated by studying the brain of five healthy volunteers and one intracranial tumor (meningioma). Apparent exchange rates in white matter range from 0.8±0.08 s(-1) in the internal capsule, to 1.6±0.11 s(-1) for frontal white matter, indicating that low values are associated with high myelination. Solid tumor displayed values of up to 2.9±0.8 s(-1). In white matter, the apparent exchange rate values suggest intra-axonal exchange times in the order of seconds, confirming the slow exchange assumption in the analysis of diffusion MRI data. We propose that filter-exchange imaging could be used clinically to map the water exchange rate in pathologies. Filter-exchange imaging may also be valuable for evaluating novel therapies targeting the function of aquaporins. Copyright © 2012 Wiley Periodicals, Inc.

  3. [Hygienic study of an activated fibrous charcoal material as a sorbing filtering element for drinking water afterpurification].

    Science.gov (United States)

    Prokopov, V A; Mironets, N V; Gakal, R K; Maktaz, E D; Dugan, A M; Teteneva, I A; Tarabarova, S B; Martyshchenko, N V; Nadvornaia, Zh D

    1993-01-01

    The results of complex toxicological and hygienic study showed that the quality of pipe water filtered through the activated carbonic fibrous material (ACFM) "Dnepr-F" forming a part of absorptive filtering element improved markedly. The content of organic substances decreased drastically as well as that of nitrates and iron. Microbiological indices did not suffer appreciable changes and were within permissible limits. The water filtered through the absorptive element with ACFM had no adverse influence on the organisms of warm-blooded animals. Proceeding from foregoing one can conclude that the "Dnepr-F" may be recommended as a part of absorptive filtering element for the final refinement of drinking water.

  4. Local drinking water filters reduce diarrheal disease in Cambodia: a randomized, controlled trial of the ceramic water purifier.

    Science.gov (United States)

    Brown, Joe; Sobsey, Mark D; Loomis, Dana

    2008-09-01

    A randomized, controlled intervention trial of two household-scale drinking water filters was conducted in a rural village in Cambodia. After collecting four weeks of baseline data on household water quality, diarrheal disease, and other data related to water use and handling practices, households were randomly assigned to one of three groups of 60 households: those receiving a ceramic water purifier (CWP), those receiving a second filter employing an iron-rich ceramic (CWP-Fe), and a control group receiving no intervention. Households were followed for 18 weeks post-baseline with biweekly follow-up. Households using either filter reported significantly less diarrheal disease during the study compared with a control group of households without filters as indicated by longitudinal prevalence ratios CWP: 0.51 (95% confidence interval [CI]: 0.41-0.63); CWP-Fe: 0.58 (95% CI: 0.47-0.71), an effect that was observed in all age groups and both sexes after controlling for clustering within households and within individuals over time.

  5. Effect of production variables on microbiological removal in locally-produced ceramic filters for household water treatment.

    Science.gov (United States)

    Lantagne, Daniele; Klarman, Molly; Mayer, Ally; Preston, Kelsey; Napotnik, Julie; Jellison, Kristen

    2010-06-01

    Diarrhoeal diseases cause an estimated 1.87 million child deaths per year. Point-of-use filtration using locally made ceramic filters improves microbiological quality of stored drinking water and prevents diarrhoeal disease. Scaling-up ceramic filtration is inhibited by lack of universal quality control standards. We investigated filter production variables to determine their affect on microbiological removal during 5-6 weeks of simulated normal use. Decreases in the clay:sawdust ratio and changes in the burnable decreased effectiveness of the filter. Method of silver application and shape of filter did not impact filter effectiveness. A maximum flow rate of 1.7 l(-hr) was established as a potential quality control measure for one particular filter to ensure 99% (2- log(10)) removal of total coliforms. Further research is indicated to determine additional production variables associated with filter effectiveness and develop standardized filter production procedures prior to scaling-up.

  6. Visual Working Memory Capacity Can Be Increased by Training on Distractor Filtering Efficiency.

    Science.gov (United States)

    Li, Cui-Hong; He, Xu; Wang, Yu-Juan; Hu, Zhe; Guo, Chun-Yan

    2017-01-01

    It is generally considered that working memory (WM) capacity is limited and that WM capacity affects cognitive processes. Distractor filtering efficiency has been suggested to be an important factor in determining the visual working memory (VWM) capacity of individuals. In the present study, we investigated whether training in visual filtering efficiency (FE) could improve VWM capacity, as measured by performance on the change detection task (CDT) and changes of contralateral delay activity (CDA) (contralateral delay activity) of different conditions, and evaluated the transfer effect of visual FE training on verbal WM and fluid intelligence, as indexed by performance on the verbal WM span task and Raven's Standard Progressive Matrices (RSPM) test, respectively. Participants were divided into high- and low-capacity groups based on their performance in a CDT designed to test VWM capacity, and then the low-capacity individuals received 20 days of FE training. The training significantly improved the group's performance in the CDT, and their CDA models of different conditions became more similar with high capacity group, and the effect generalized to improve verbal WM span. These gains were maintained at a 3-month follow-up test. Participants' RSPM scores were not changed by the training. These findings support the notion that WM capacity is determined, at least in part, by distractor FE and can be enhanced through training.

  7. Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification c...... a pilot scale sand column which initial analysis confirmed performed similarly to the full scale filters. Long term increased ammonium loads were applied to the pilot filter both with and without phosphate addition. Phosphate was added at a concentration of 0.5 mg PO4-P/L to ensure...

  8. Investigations on the retention of 131I by an iodine filter of a pressurized water reactor

    International Nuclear Information System (INIS)

    Deuber, H.; Gerlach, K.

    1983-09-01

    The retention of 131 I by an equipment room exhaust filter of a German pressurized water reactor was determined by various methods to particularly obtain reliable results. Moreover, investigations were performed to clarify the reason for aging of the carbon contained in the iodine filter mentioned. The actual retention of the organic 131 I, corresponding to a value of 99.9%, was limited by 131 I in the form of penetrating iodine compounds. It was lower than the retention of CH 3 131 I under layout conditions by more than one order of magnitude. The aging was essentially caused by the adsorption of low-volatile organic compounds. (orig.) [de

  9. Investigations on the retention of I-131 by an iodine filter of a pressurized water reactor

    International Nuclear Information System (INIS)

    Deuber, H.; Gerlach, K.

    1984-01-01

    The retention of I-131 by an equipment room exhaust filter of a German pressurized water reactor was determined by various methods to particularly obtain reliable results. Moreover, investigations were performed to clarify the reason for aging of the carbon contained in the iodine filter mentioned. The actual retention of the organic I-131, corresponding to a value of 99.9%, was limited by I-131 in the form of penetrating iodine compounds. It was lower than the retention of CH 3 I-131 under layout conditions by more than one order of magnitude. The aging was essentially caused by the adsorption of low-volatile organic compounds. (orig.) [de

  10. Nickel removal from nickel plating waste water using a biologically active moving-bed sand filter.

    Science.gov (United States)

    Pümpel, Thomas; Macaskie, Lynne E; Finlay, John A; Diels, Ludo; Tsezos, Marios

    2003-12-01

    Efficient removal of dissolved nickel was observed in a biologically active moving-bed 'MERESAFIN' sand filter treating rinsing water from an electroless nickel plating plant. Although nickel is fully soluble in this waste water, its passage through the sand filter promoted rapid removal of approximately 1 mg Ni/l. The speciation of Ni in the waste water was modelled; the most probable precipitates forming under the conditions in the filter were predicted using PHREEQC. Analyses of the Ni-containing biosludge using chemical, electron microscopical and X-ray spectroscopic techniques confirmed crystallisation of nickel phosphate as arupite (Ni3(PO4)2 x 8H2O), together with hydroxyapatite within the bacterial biofilm on the filter sand grains. Biosorption contributed less than 1% of the overall sequestered nickel. Metabolising bacteria are essential for the process; the definitive role of specific components of the mixed population is undefined but the increase in pH promoted by metabolic activity of some microbial components is likely to promote nickel desolubilisation by others.

  11. Metal oxide/hydroxide-coated dual-media filter for simultaneous removal of bacteria and heavy metals from natural waters.

    Science.gov (United States)

    Ahammed, M Mansoor; Meera, V

    2010-09-15

    The present study was conducted to compare the performance of a dual-media filter consisting of manganese oxide-coated (MOCS) and iron hydroxide-coated sand (IOCS) with that of IOCS filter and uncoated sand filter in treating water contaminated by microorganisms, heavy metals and turbidity with a view to its use in simple household water purification devices in developing countries. Long-duration column tests were conducted using two natural waters namely, roof-harvested rainwater and canal water. Performance of the filters showed that dual-media filter was more efficient in removing bacteria and heavy metals compared to IOCS filter, while uncoated sand filter showed very poor performance. The average effluent levels for dual-media filter when tested with rainwater were: turbidity 1.0+/-0.1 NTU; total coliforms 3+/-2 MPN/100 mL; heterotrophic plate count 170+/-20 CFU/mL; zinc 0.06+/-0.01 mg/L, while that for IOCS filter were: turbidity 1.0+/-0.1 NTU; total coliforms 4+/-2 MPN/100 mL; heterotrophic plate count 181+/-37 CFU/mL; zinc 0.20+/-0.07 mg/L. Similar results were obtained for canal water also. Up to 900 bed volumes (BV) could be treated without affecting the efficiency in the case of rainwater, while the filter operation had to be terminated after 500 BV due to excessive headloss in the case of canal water. The study thus showed the potential of the dual-media for use in low-cost household water filters for purification of natural waters. Copyright 2010 Elsevier B.V. All rights reserved.

  12. The segregation of silver nanoparticles in low-cost ceramic water filters

    International Nuclear Information System (INIS)

    Larimer, Curtis; Ostrowski, Nicole; Speakman, Jacquelyn; Nettleship, Ian

    2010-01-01

    As an impregnated constituent in low-cost ceramic water filters, silver nanoparticles have a demonstrated antibacterial effect. The bactericidal mechanism is believed to be based on direct contact between silver and the cell wall of a contaminant organism. In this study microstructural analysis was used to examine the effect of the processing method on the distribution of silver nanoparticles in the filter material. Silver nanofluid was impregnated into fired clay ceramic samples by a low-cost soak-and-dry method. Analyses of filter samples by scanning electron microscopy, energy dispersive spectroscopy, and digital optical topological mapping showed that silver was concentrated in near surface pores, a condition that is not optimal for highest probability of silver contact. A simple experiment showed that segregation of silver occurs during the drying phase of impregnation. Drying curves showed that 90% of contained liquid evaporates from the external surface.

  13. Flattening filter-free accelerators: a report from the AAPM Therapy Emerging Technology Assessment Work Group.

    Science.gov (United States)

    Xiao, Ying; Kry, Stephen F; Popple, Richard; Yorke, Ellen; Papanikolaou, Niko; Stathakis, Sotirios; Xia, Ping; Huq, Saiful; Bayouth, John; Galvin, James; Yin, Fang-Fang

    2015-05-08

    This report describes the current state of flattening filter-free (FFF) radiotherapy beams implemented on conventional linear accelerators, and is aimed primarily at practicing medical physicists. The Therapy Emerging Technology Assessment Work Group of the American Association of Physicists in Medicine (AAPM) formed a writing group to assess FFF technology. The published literature on FFF technology was reviewed, along with technical specifications provided by vendors. Based on this information, supplemented by the clinical experience of the group members, consensus guidelines and recommendations for implementation of FFF technology were developed. Areas in need of further investigation were identified. Removing the flattening filter increases beam intensity, especially near the central axis. Increased intensity reduces treatment time, especially for high-dose stereotactic radiotherapy/radiosurgery (SRT/SRS). Furthermore, removing the flattening filter reduces out-of-field dose and improves beam modeling accuracy. FFF beams are advantageous for small field (e.g., SRS) treatments and are appropriate for intensity-modulated radiotherapy (IMRT). For conventional 3D radiotherapy of large targets, FFF beams may be disadvantageous compared to flattened beams because of the heterogeneity of FFF beam across the target (unless modulation is employed). For any application, the nonflat beam characteristics and substantially higher dose rates require consideration during the commissioning and quality assurance processes relative to flattened beams, and the appropriate clinical use of the technology needs to be identified. Consideration also needs to be given to these unique characteristics when undertaking facility planning. Several areas still warrant further research and development. Recommendations pertinent to FFF technology, including acceptance testing, commissioning, quality assurance, radiation safety, and facility planning, are presented. Examples of clinical

  14. Removal of virus to protozoan sized particles in point-of-use ceramic water filters.

    Science.gov (United States)

    Bielefeldt, Angela R; Kowalski, Kate; Schilling, Cherylynn; Schreier, Simon; Kohler, Amanda; Scott Summers, R

    2010-03-01

    The particle removal performance of point-of-use ceramic water filters (CWFs) was characterized in the size range of 0.02-100 microm using carboxylate-coated polystyrene fluorescent microspheres, natural particles and clay. Particles were spiked into dechlorinated tap water, and three successive water batches treated in each of six different CWFs. Particle removal generally increased with increasing size. The removal of virus-sized 0.02 and 0.1 microm spheres were highly variable between the six filters, ranging from 63 to 99.6%. For the 0.5 microm spheres removal was less variable and in the range of 95.1-99.6%, while for the 1, 2, 4.5, and 10 microm spheres removal was >99.6%. Recoating four of the CWFs with colloidal silver solution improved removal of the 0.02 microm spheres, but had no significant effects on the other particle sizes. Log removals of 1.8-3.2 were found for natural turbidity and spiked kaolin clay particles; however, particles as large as 95 microm were detected in filtered water. Copyright 2009 Elsevier Ltd. All rights reserved.

  15. Potential of simple filters to improve microbial quality of irrigation water used in urban vegetable farming in Ghana

    DEFF Research Database (Denmark)

    Keraita, Bernard; Drechsel, Pay; Konradsen, Flemming

    2008-01-01

    . As part of a larger study on possible interventions for health risk reduction, the potential of simple interventions was explored. Column slow sand filters with three levels of sand depths (0.5 m, 0.75 m and 1 m) and fabric filters made of nylon, cotton and netting were assessed. More than 600 water...... samples were analyzed for helminth eggs and thermotolerant coliforms. Flow rates were also measured. From slow sand filters, 71-96% of helminths and 2 log units (from 7 to 5 log units) of thermotolerant coliforms were removed. Sand depths had no significant influence in the removal. Lower removal rates...... were achieved by fabric filters, with an average removal of 12-62% for helminth eggs and 1 log unit for thermotolerant coliforms. Nylon filters had higher removal rates especially for helminth eggs (58%). Average flow rates for sand filters were 3 m per day and fabric filters had steady flows of about...

  16. MATLAB algorithm to implement soil water data assimilation with the Ensemble Kalman Filter using HYDRUS.

    Science.gov (United States)

    Valdes-Abellan, Javier; Pachepsky, Yakov; Martinez, Gonzalo

    2018-01-01

    Data assimilation is becoming a promising technique in hydrologic modelling to update not only model states but also to infer model parameters, specifically to infer soil hydraulic properties in Richard-equation-based soil water models. The Ensemble Kalman Filter method is one of the most widely employed method among the different data assimilation alternatives. In this study the complete Matlab© code used to study soil data assimilation efficiency under different soil and climatic conditions is shown. The code shows the method how data assimilation through EnKF was implemented. Richards equation was solved by the used of Hydrus-1D software which was run from Matlab. •MATLAB routines are released to be used/modified without restrictions for other researchers•Data assimilation Ensemble Kalman Filter method code.•Soil water Richard equation flow solved by Hydrus-1D.

  17. Drawer compacted sand filter: a new and innovative method for on-site grey water treatment.

    Science.gov (United States)

    Assayed, Almoayied; Chenoweth, Jonathan; Pedley, Steven

    2014-01-01

    In this paper, results ofa new sand filter design were presented. The drawer compacted sand filter (DCSF) is a modified design for a sand filter in which the sand layer is broken down into several layers, each of which is 10 cm high and placed in a movable drawer separated by a 10 cm space. A lab-scale DCSF was designed and operated for 330 days fed by synthetic grey water. The response of drawer sand filters to variable hydraulic and organic loading rates (HLR and OLR) in terms of biological oxygen demand (BODs), chemical oxygen demand (COD), total suspended solids (TSS), pH, electrical conductivity and Escherichia coli reductions were evaluated. The HLR was studied by increasing from 72 to 142 L m(-2) day(-1) and OLR was studied by increasing it from 23 to 30 g BOD5 m(-2) day(-1) while keeping the HLR constant at 142 L m(-2) day(-1). Each loading regime was applied for 110 days. Results showed that DCSF was able to remove >90% of organic matter and total suspended solids for all doses. No significant difference was noticed in terms of overall filter efficiency between different loads for all parameters. Significant reduction in BOD5 and COD (P water was drained through the third drawer in all tested loads. The paper concludes that DCSF would be appropriate for use in dense urban areas as its footprint is small and is appropriate for a wide range of users because of its convenience and low maintenance requirements.

  18. Working group report on water resources

    International Nuclear Information System (INIS)

    Baulder, J.

    1991-01-01

    The results and conclusions of a working group held to discuss climate change implications for water resources are presented. The existing water resources and climatological databases necessary to develop models and functional relationships lack integration and coordination. The density and spatial distribution of the existing sampling networks for obtaining necessary climatological data is inadequate, especially in areas of complex terrain, notably higher elevations in the Rocky Mountains. Little information and knowledge is available on potential socio-economic responses that can be anticipated from either increases in climate variability or major change. Recommended research initiatives include the following. Basic functional relationships between climatic events, climatic variability and change, and both surface and groundwater hydrologic processes need to be investigated and improved. Basin-scale and regional-scale climatic models need to be developed, tested, and interfaced with existing global climate models. Public sector attitudes to water management issues and opportunities need to be investigated, and integrated scientific, socio-economic, multidisciplinary, regional databases on climatic change and variability and associated processes need to be developed

  19. COMPUTER MODELING OF HYDRODYNAMIC PARAMETERS AT BOUNDARIES OF WATER INTAKE AREA WITH FILTERING INTAKE

    Directory of Open Access Journals (Sweden)

    Boronina Lyudmila Vladimirovna

    2012-12-01

    Full Text Available Improvement of water intake technologies are of great importance. These technologies are required to provide high quality water intake and treatment; they must be sufficiently simple and reliable, and they must be easily adjustable to particular local conditions. A mathematical model of a water supply area near the filtering water intake is proposed. On its basis, a software package designated for the calculation of parameters of the supply area along with its graphical representation is developed. To improve the efficiency of water treatment plants, the authors propose a new method of their integration into the landscape by taking account of velocity distributions in the water supply area within the water reservoir where the plant installation is planned. In the proposed relationship, the filtration rate and the scattering rate at the outlet of the supply area are taken into account, and they assure more precise projections of the inlet velocity. In the present study, assessment of accuracy of the mathematical model involving the scattering of a turbulent flow has been done. The assessment procedure is based on verification of the mean values equality hypothesis and on comparison with the experimental data. The results and conclusions obtained by means of the method developed by the authors have been verified through comparison of deviations of specific values calculated through the employment of similar algorithms in MathCAD, Maple and PLUMBING. The method of the water supply area analysis, with the turbulent scattering area having been taken into account, and the software package enable to numerically estimate the efficiency of the pre-purification process by tailoring a number of parameters of the filtering component of the water intake to the river hydrodynamic properties. Therefore, the method and the software package provide a new tool for better design, installation and operation of water treatment plants with respect to filtration and

  20. In situ bioremediation of trichloroethylene-contaminated water by a resting-cell methanotrophic microbial filter

    International Nuclear Information System (INIS)

    Taylor, R.T.; Duba, A.G.; Durham, W.B.; Hanna, M.L.; Jackson, K.J.; Jovanovich, M.C.; Knapp, R.B.; Knezovich, J.P.; Shah, N.N.; Shonnard, D.R.; Wijesinghe, A.M.

    1992-10-01

    The Lawrence Livermore National Laboratory is testing and developing an in situ microbial filter technology for remediating migrating subsurface plumes contaminated with low concentrations of trichloroethylene (TCE). Their current focus is the establishment of a replenishable bioactive zone (catalytic filter) along expanding plume boundaries by the Injection of a representative methanotrophic bacterium, Methylosinus trichosporium OB3b. We have successfully demonstrated this microbial filter strategy using emplaced, attached resting cells (no methane additions) in a 1.1-m flow-through test bed loaded with water-saturated sand. Two separate 24 h pulses of TCE (109 ppb and 85 ppb), one week apart, were pumped through the system at a flow velocity of 1.5 cm/h; no TCE (<0.5 ppb) was detected on the downstream side of the microbial filter. Subsequent excavation of the wet sand confirmed the existence of a TCE-bioactive zone 19 days after it had been created. An enhanced longevity of the cellular, soluble-form methane monooxygenase produced by this methanotroph Is a result of our laboratory bioreactor culturing conditions. Additional experiments with cells in sealed vials and emplaced in the 1.1-m test bed yielded a high resting-cell finite TCE biotransformation capacity of ∼ 0.25 mg per mg of bacteria; this is suitable for a planned sand-filled trench field demonstration at a Lawrence Livermore National Laboratory site

  1. Pseudobrookite-type MgTi2O5 water purification filter with controlled particle morphology

    Directory of Open Access Journals (Sweden)

    Yuta Nakagoshi

    2015-09-01

    Full Text Available Pseudobrookite-type oxide-based ceramics, such as Al2TiO5 and MgTi2O5, have recently been studied as porous ceramic membranes. Here, the effect of LiF doping on the morphology of MgTi2O5 particles is presented in detail. Water purification filters were produced using porous MgTi2O5, with different particle morphologies. MgCO3 (basic and TiO2 powders with various LiF contents were wet-ball milled, dried, and then, calcined in air at 1100 °C to obtain the MgTi2O5 powders. The powder compacts were sintered at 1000–1200 °C to produce the MgTi2O5 disk filters. The 0.5 wt.% LiF-doped MgTi2O5 disk filter, with elongated grains, showed well-balanced performance removing boehmite particles with diameter of 0.7 μm. Non-doped MgTi2O5 disk filter with equiaxed grains was suitable for precise filtration.

  2. Optimisation and significance of ATP analysis for measuring active biomass in granular activated carbon filters used in water treatment

    NARCIS (Netherlands)

    Magic-Knezev, A.; Kooij, van der D.

    2004-01-01

    A method for determining the concentration of active microbial biomass in granular activated carbon (GAC) filters used in water treatment was developed to facilitate studies on the interactions between adsorption processes and biological activity in such filters. High-energy sonication at a power

  3. Processing Functional Near Infrared Spectroscopy Signal with a Kalman Filter to Assess Working Memory during Simulated Flight.

    Directory of Open Access Journals (Sweden)

    Gautier eDurantin

    2016-01-01

    Full Text Available Working memory is a key executive function for operating aircraft, especially when pilots have to recall series of air traffic control instructions. There is a need to implement tools to monitor working memory as its limitation may jeopardize flight safety. An innovative way to address this issue is to adopt a Neuroergonomics approach that merges knowledge and methods from Human Factors, System Engineering and Neuroscience. A challenge of great importance for Neuroergonomics is to implement efficient brain imaging techniques to measure the brain at work and to design Brain Computer Interfaces. We used functional near infrared spectroscopy as it has been already successfully tested to measure working memory capacity in complex environment with air traffic controllers, pilots or unmanned vehicle operators. However, the extraction of relevant features from the raw signal in ecological environment is still a critical issue due to the complexity of implementing real-time signal processing techniques without a priori knowledge. We proposed to implement the Kalman filtering approach, a signal processing technique that is efficient when the dynamics of the signal can be modeled. We based our approach on the Boynton model of hemodynamic response. We conducted a first experiment with 9 participants involving a basic working memory task to estimate the noise covariances of the Kalman filter. We then conducted a more ecological experiment in our flight simulator with 18 pilots who interacted with air traffic controller instructions (two levels of difficulty. The data was processed with the same Kalman filter settings implemented in the first experiment. This filter was benchmarked with a classical pass-band IIR filter and a Moving Average Convergence Divergence filter. Statistical analysis revealed that the Kalman filter was the most efficient to separate the two levels of load, by increasing the observed effect size in prefrontal areas involved in working

  4. Reducing and verifying haloacetic acids in treated drinking water using a biological filter system.

    Science.gov (United States)

    Lou, Jie C; Chan, Hung Y; Yang, Chih Y; Tseng, Wei B; Han, Jia Y

    2014-01-01

    This study focused on reducing the haloacetic acid (HAA) concentrations in treated drinking water. HAA has been thought to be one possible nutrient supporting heterotrophic bacteria regrowth in drinking water. In this study, experiments were conducted using a pilot-scale system to evaluate the efficiency of biological filters (BF) for reducing excess HAA concentrations in water. The BF system reduced the total HAA concentration and the concentrations of five HAA species in the water. Dichloroacetic acid (DCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA) were the three main HAA5 species that were present in the treated drinking water in this investigation. Combined, these three species represent approximately 77% of the HAA5 in the finished water after BF. The verification of the empirical HAA equation for the outlet in the BF system indicated linear relationships with high correlation coefficients. The empirical equation for the HAA5 concentrations in the finished water was established by examining other nutrients (e.g., dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm wavelength (UV254), and ammonia nitrogen) that can reduce pathogenic contamination. These findings may be useful for designing advanced processes for conventional water treatment plants or for managing water treatment and distribution systems for providing high-quality drinking water.

  5. [Determination of five representative ultraviolet filters in water by gas chromatography-mass spectrometry].

    Science.gov (United States)

    Ding, Yiran; Huang, Yun; Zhao, Tingting; Cai, Qian; Luo, Yu; Huang, Bin; Zhang, Yuxia; Pan, Xuejun

    2014-06-01

    A method for the determination of five representative organic UV filters: ethylhexyl methoxycinnamate (EHMC), benzophenone-3 (BP-3), 4-methylbenzylidene camphor (4-MBC), octocrylene (OC), homosalate (HMS) in water was investigated. The method was ased on derivatization, solid phase extraction (SPE), followed by determination with gas chromatography-mass spectrometry (GC-MS). The variables involved in the derivatization of BP-3 and HMS were optimized, and SPE conditions were studied. For derivatization, 100 microL N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) was used as derivatization reagent and reacted with BP-3 and HMS at 100 degrees C for 100 min. For SPE, the pH value of water sample was adjusted to 3-5. The Oasis HLB cartridges were employed and the solution of ethyl acetate and dichloromethane (1 : 1, v/v) was used as the eluting solvent, and good recoveries of the target compounds were obtained. The limits of detection (LODs) and the limits of quantification (LOQs) for the five target compounds in water samples were 0.5-1.2 ng/L and 1.4-4.0 ng/L, respectively. The recoveries of spiked water samples were 87.85%-102.34% with good repeatability and reproducibility (RSD < 5%, n = 3) for all the target compounds. Finally, the validated method was applied to analysis the representative UV filters in water samples collected from a wastewater treatment plant in Kunming city of Yunnan province.

  6. An Improved Cambridge Filter Pad Extraction Methodology to Obtain More Accurate Water and “Tar” Values: In Situ Cambridge Filter Pad Extraction Methodology

    OpenAIRE

    Ghosh David; Jeannet Cyril

    2014-01-01

    Previous investigations by others and internal investigations at Philip Morris International (PMI) have shown that the standard trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387 (Cigarettes -- Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine), is not suitable for high-water content aerosols. Errors occur because of water losses during the opening of the Cambridge filter p...

  7. Metals, heavy metals and microorganism removal from spent filter backwash water by hybrid coagulation-UF processes

    Directory of Open Access Journals (Sweden)

    Mokhtar Mahdavi

    2018-04-01

    Full Text Available Spent filter backwash water (SFBW reuse has attracted particular attention, especially in countries that experience water scarcity. It can act as a permanent water source until the water treatment plant is working. In this study, the concentrations of Fe, Al, Pb, As, and Cd with total and fecal coliform (TC/FC were investigated in raw and treated SFBW by hybrid coagulation-UF processes. The pilot plant consisted of pre-sedimentation, coagulation, flocculation, clarification, and ultrafiltration (UF units. Poly-aluminum ferric chloride (PAFCL and ferric chloride (FeCl3 were used as pretreatment. The results showed that, at the optimum dose of PAFCl, the average removal of TC and FC was 88 and 79% and with PAFCl-UF process, it reached 100 and 100%, respectively. For FeCl3, removal efficiency of TC and FC were 81 and 72% and by applying FeCl3-UF process, it reached 100 and 100%, respectively. In comparison with FeCl3, PAFCl showed better removal efficiency for Fe, Pb, As, and Cd, except residual Al concentration. Coagulation-UF process could treat SFBW efficiently and treated SFBW could meet the US-EPA drinking water standard. Health risk index values of Fe, AL, Pb, AS, and Cd in treated SFBW indicate no risk of exposure to the use of this water.

  8. Enteric virus removal from water by coal-based sorbents: development of low-cost water filters

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, M.; Sattar, S.A.

    1986-01-01

    Using poliovirus type 1 (Sabin) and dechlorinated tap water, several coal-based sorbents were tested for their capacity to remove viruses from water. The sorbents included bituminous coal from Giridih, India, pretreated/impregnated with either alum, ferric hydroxide, lime or manganese dioxide. Filtrasorb-400, commercially available active carbon, was used as a reference. In batch tests, with input virus concentration of 2.34-2.83x10/sup 6/ PFU/1 and sorbent concentration of 10 g/l, alum pretreated coal removed about 96% of the virus when pH of the water was between 6.3 and 8.9. Virus sorption was rapid and a plateau was reached in 30 min. Compared with the active carbon, alum pretreated coal exhibited greater sorption energy and about one log higher limiting poliovirus sorption capacity. Downflow column study indicated the potential of alum pretreated coal as a filter media for removing enteric viruses from water. A previous study showed this sorbent to be capable of removing enteric bacteria as well. Water filters prepared from such low-cost material may prove useful for domestic use in rural areas of India and other developing countries. 19 refs.

  9. 46 CFR 109.334 - Working over water.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Working over water. 109.334 Section 109.334 Shipping... Operation and Stowage of Safety Equipment § 109.334 Working over water. The master or person in charge shall insure that each person working over the water is wearing a life preserver or a buoyant work vest. ...

  10. Organic/inorganic hybrid filters based on dendritic and cyclodextrin "nanosponges" for the removal of organic pollutants from water.

    Science.gov (United States)

    Arkas, Michael; Allabashi, Roza; Tsiourvas, Dimitris; Mattausch, Eva-Maria; Perfler, Reinhard

    2006-04-15

    Long-alkyl chain functionalized poly(propylene imine) dendrimer, poly(ethylene imine) hyperbranched polymer, and beta-cyclodextrin derivatives, which are completely insoluble in water, have the property of encapsulating organic pollutants from water. Ceramic porous filters can be impregnated with these compounds resulting in hybrid organic/ inorganic filter modules. These hybrid filter modules were tested for the effective purification of water, by continuous filtration experiments, employing a variety of water pollutants. It has been established that polycyclic aromatic hydrocarbons (PAHs) can be removed very efficiently (more than 95%), and final concentrations of several ppb (microg/ L) are easily obtained. Representatives of the pollutant group of trihalogen methanes (THMs), monoaromatic hydrocarbons (BTX), and pesticides (simazine) can also be removed (>80%), although the filters are saturated considerably faster in these cases.

  11. Modeling Adsorption Based Filters (Bio-remediation of Heavy Metal Contaminated Water)

    Science.gov (United States)

    McCarthy, Chris

    I will discuss kinetic models of adsorption, as well as models of filters based on those mechanisms. These mathematical models have been developed in support of our interdisciplinary lab group, which is centered at BMCC/CUNY (City University of New York). Our group conducts research into bio-remediation of heavy metal contaminated water via filtration. The filters are constructed out of biomass, such as spent tea leaves. The spent tea leaves are available in large quantities as a result of the industrial production of tea beverages. The heavy metals bond with the surfaces of the tea leaves (adsorption). The models involve differential equations, stochastic methods, and recursive functions. I will compare the models' predictions to data obtained from computer simulations and experimentally by our lab group. Funding: CUNY Collaborative Incentive Research Grant (Round 12); CUNY Research Scholars Program.

  12. Pressurized water reactor monitoring. Study of detection, diagnostic and estimation methods (least error squares and filtering)

    International Nuclear Information System (INIS)

    Gillet, M.

    1986-07-01

    This thesis presents a study for the surveillance of the ''primary coolant circuit inventory monitoring'' of a pressurized water reactor. A reference model is developed in view of an automatic system ensuring detection and diagnostic in real time. The methods used for the present application are statistical tests and a method related to pattern recognition. The estimation of failures detected, difficult owing to the non-linearity of the problem, is treated by the least error squares method of the predictor or corrector type, and by filtering. It is in this frame that a new optimized method with superlinear convergence is developed, and that a segmented linearization of the model is introduced, in view of a multiple filtering [fr

  13. Program plan for the investigation of vent-filtered containment conceptual designs for light water reactors

    International Nuclear Information System (INIS)

    Benjamin, A.S.

    1979-10-01

    The implementation of a containment venting and filtration capability has been suggested as a means for reducing the risk from fuel melt accidents in light water reactors. The risk reduction potential of such systems depends upon the dual function of venting containment to prevent overpressurization from the generation of steam and noncondensibles and filtering the effluent to limit the release of radioactive materials. This report addresses the major issues involved in such an accident mitigation system and discusses the engineering, technical, and economic questions that will have to be studied before judgments can be made regarding feasibility and effectiveness. A program plan is presented for research leading to the formulation of design requirements for vent-filter containment systems and to a comprehensive assessment of the values versus impacts of such systems

  14. Adaptive Kalman Filter Based on Adjustable Sampling Interval in Burst Detection for Water Distribution System

    Directory of Open Access Journals (Sweden)

    Doo Yong Choi

    2016-04-01

    Full Text Available Rapid detection of bursts and leaks in water distribution systems (WDSs can reduce the social and economic costs incurred through direct loss of water into the ground, additional energy demand for water supply, and service interruptions. Many real-time burst detection models have been developed in accordance with the use of supervisory control and data acquisition (SCADA systems and the establishment of district meter areas (DMAs. Nonetheless, no consideration has been given to how frequently a flow meter measures and transmits data for predicting breaks and leaks in pipes. This paper analyzes the effect of sampling interval when an adaptive Kalman filter is used for detecting bursts in a WDS. A new sampling algorithm is presented that adjusts the sampling interval depending on the normalized residuals of flow after filtering. The proposed algorithm is applied to a virtual sinusoidal flow curve and real DMA flow data obtained from Jeongeup city in South Korea. The simulation results prove that the self-adjusting algorithm for determining the sampling interval is efficient and maintains reasonable accuracy in burst detection. The proposed sampling method has a significant potential for water utilities to build and operate real-time DMA monitoring systems combined with smart customer metering systems.

  15. Development of biomass in a drinking water granular active carbon (GAC) filter.

    Science.gov (United States)

    Velten, Silvana; Boller, Markus; Köster, Oliver; Helbing, Jakob; Weilenmann, Hans-Ulrich; Hammes, Frederik

    2011-12-01

    Indigenous bacteria are essential for the performance of drinking water biofilters, yet this biological component remains poorly characterized. In the present study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the first six months of operation. GAC particles were sampled from four different depths (10, 45, 80 and 115 cm) and attached biomass was measured with adenosine tri-phosphate (ATP) analysis. The attached biomass accumulated rapidly on the GAC particles throughout all levels in the filter during the first 90 days of operation and maintained a steady state afterward. Vertical gradients of biomass density and growth rates were observed during start-up and also in steady state. During steady state, biomass concentrations ranged between 0.8-1.83 x 10(-6) g ATP/g GAC in the filter, and 22% of the influent dissolved organic carbon (DOC) was removed. Concomitant biomass production was about 1.8 × 10(12) cells/m(2)h, which represents a yield of 1.26 × 10(6) cells/μg. The bacteria assimilated only about 3% of the removed carbon as biomass. At one point during the operational period, a natural 5-fold increase in the influent phytoplankton concentration occurred. As a result, influent assimilable organic carbon concentrations increased and suspended bacteria in the filter effluent increased 3-fold as the direct consequence of increased growth in the biofilter. This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilters. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Design, construction and operation of a new filter approach for treatment of surface waters in Southeast Asia

    Science.gov (United States)

    Frankel, R. J.

    1981-05-01

    A simple, inexpensive, and efficient method of water treatment for rural communities in Southeast Asia was developed using local materials as filter media. The filter utilizes coconut fiber and burnt rice husks in a two-stage filtering process designed as a gravityfed system without the need for backwashing, and eliminates in most cases the need of any chemicals. The first-stage filter with coconut fiber acts essentially as a substitute for the coagulation and sedimentation phases of conventional water-treatment plants. The second-stage filter, using burnt rice husks, is similar to slow sand filtration with the additional benefits of taste, color and odor removals through the absorption properties of the activated carbon in the medium. This paper reports on the design, construction costs, and operating results of several village size units in Thailand and in the Philippines.

  17. Designing Programme Implementation Strategies to Increase the Adoption and Use of Biosand Water Filters in Rural India

    OpenAIRE

    Tommy K.K. Ngai; Richard A. Fenner

    2014-01-01

    Low-cost household water treatment systems are innovations designed to improve the quality of drinking water at the point of use. This study investigates how an NGO can design appropriate programme strategies in order to increase the adoption and sustained use of household sand filters in rural India. A system dynamics computer model was developed and used to assess 18 potential programme strategies for their effectiveness in increasing filter use at two and ten years into the future, under s...

  18. Filter cake breaker systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo H.F. [Poland Quimica Ltda., Duque de Caxias, RJ (Brazil)

    2004-07-01

    Drilling fluids filter cakes are based on a combination of properly graded dispersed particles and polysaccharide polymers. High efficiency filter cakes are formed by these combination , and their formation on wellbore walls during the drilling process has, among other roles, the task of protecting the formation from instantaneous or accumulative invasion of drilling fluid filtrate, granting stability to well and production zones. Filter cake minimizes contact between drilling fluid filtrate and water, hydrocarbons and clay existent in formations. The uniform removal of the filter cake from the entire interval is a critical factor of the completion process. The main methods used to breaking filter cake are classified into two groups, external or internal, according to their removal mechanism. The aim of this work is the presentation of these mechanisms as well their efficiency. (author)

  19. Computational Methods to Work as First-Pass Filter in Deleterious SNP Analysis of Alkaptonuria

    Directory of Open Access Journals (Sweden)

    R. Magesh

    2012-01-01

    Full Text Available A major challenge in the analysis of human genetic variation is to distinguish functional from nonfunctional SNPs. Discovering these functional SNPs is one of the main goals of modern genetics and genomics studies. There is a need to effectively and efficiently identify functionally important nsSNPs which may be deleterious or disease causing and to identify their molecular effects. The prediction of phenotype of nsSNPs by computational analysis may provide a good way to explore the function of nsSNPs and its relationship with susceptibility to disease. In this context, we surveyed and compared variation databases along with in silico prediction programs to assess the effects of deleterious functional variants on protein functions. In other respects, we attempted these methods to work as first-pass filter to identify the deleterious substitutions worth pursuing for further experimental research. In this analysis, we used the existing computational methods to explore the mutation-structure-function relationship in HGD gene causing alkaptonuria.

  20. Computational Methods to Work as First-Pass Filter in Deleterious SNP Analysis of Alkaptonuria

    Science.gov (United States)

    Magesh, R.; George Priya Doss, C.

    2012-01-01

    A major challenge in the analysis of human genetic variation is to distinguish functional from nonfunctional SNPs. Discovering these functional SNPs is one of the main goals of modern genetics and genomics studies. There is a need to effectively and efficiently identify functionally important nsSNPs which may be deleterious or disease causing and to identify their molecular effects. The prediction of phenotype of nsSNPs by computational analysis may provide a good way to explore the function of nsSNPs and its relationship with susceptibility to disease. In this context, we surveyed and compared variation databases along with in silico prediction programs to assess the effects of deleterious functional variants on protein functions. In other respects, we attempted these methods to work as first-pass filter to identify the deleterious substitutions worth pursuing for further experimental research. In this analysis, we used the existing computational methods to explore the mutation-structure-function relationship in HGD gene causing alkaptonuria. PMID:22606059

  1. Effect of silver nanoparticle coatings on mycobacterial biofilm attachment and growth: Implications for ceramic water filters

    Science.gov (United States)

    Larimer, Curtis James

    Silver is a natural, broad-spectrum antibacterial metal and its toxicity can be enhanced when surface area is maximized. As a result, silver nanoparticles (AgNP) have been investigated for use in novel water treatment technologies. The hypothesis of this work is that deposited AgNPs can enhance water treatment technologies by inhibiting growth of planktonic bacteria and biofilms. This was investigated by evaluating the antibacterial efficacy of AgNPs both in solution and as deposited on surfaces. AgNPs were found to be toxic to three species of environmental mycobacteria, M. smegmatis, M. avium, and M. marinum and the level of susceptibility varied widely, probably owing to the varying levels of silver that each species is exposed to in its natural environment. When cultured in a AgNP enriched environment M. smegmatis developed resistance to the toxic effects of both the nanoparticles and silver ions. The resistant mutant was as viable as the unmodified strain and was also resistant to antibiotic isoniazid. However, the strain was more susceptible to other toxic metal ions from ZnSO4 and CuSO4. AgNPs were deposited on silicon wafer substrates by vertical colloidal deposition (VCD). Manipulating deposition speed and also concentration of AgNPs in the depositing liquid led to a range of AgNP coatings with distinctive deposition lines perpendicular to the motion of the meniscus. Experimental results for areal coverage, which was measured from SEM images of AgNP coatings, were compared to Diao's theory of VCD but did not show agreement due to a stick-slip mechanism that is not accounted for by the theory. Durability of AgNP coatings is critical for antibacterial efficacy and to mitigate the risks of exposing the environment to nanomaterials and it was measured by exposing AgNP coatings to liquid flow in a flow cell. Durability was improved by modifying processing to include a heat treatment after deposition. Finally, the antibiofilm efficacy of deposited AgNPs was

  2. Biological filters and their use in potable water filtration systems in spaceflight conditions

    Science.gov (United States)

    Thornhill, Starla G.; Kumar, Manish

    2018-05-01

    Providing drinking water to space missions such as the International Space Station (ISS) is a costly requirement for human habitation. To limit the costs of water transport, wastewater is collected and purified using a variety of physical and chemical means. To date, sand-based biofilters have been designed to function against gravity, and biofilms have been shown to form in microgravity conditions. Development of a universal silver-recycling biological filter system that is able to function in both microgravity and full gravity conditions would reduce the costs incurred in removing organic contaminants from wastewater by limiting the energy and chemical inputs required. This paper aims to propose the use of a sand-substrate biofilter to replace chemical means of water purification on manned spaceflights.

  3. Reverse Osmosis Filter Use and High Arsenic Levels in Private Well Water

    Science.gov (United States)

    George, Christine M.; Smith, Allan H.; Kalman, David A.; Steinmaus, Craig M.

    2013-01-01

    Inorganic arsenic causes cancer, and millions of people worldwide are exposed to arsenic-contaminated water. Regulatory standards for arsenic levels in drinking water generally do not apply to private domestic wells. Reverse osmosis (RO) units commonly are used by well owners to reduce arsenic concentrations, but may not always be effective. In a survey of 102 homes in Nevada, 19 used RO devices. Pre- and post-RO filtration arsenic concentrations averaged 443 μg/l and 87 μg/l, respectively. The average absolute and percent reductions in arsenic concentrations after filtration were 356 μg/l and 79%, respectively. Postfiltration concentrations were higher than 10 μg/l in 10 homes and higher than 100 μg/l in 4 homes. These findings provide evidence that RO filters do not guarantee safe drinking water and, despite regulatory standards, some people continue to be exposed to very high arsenic concentrations. PMID:17867571

  4. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    Science.gov (United States)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  5. Concerted action of two cation filters in the aquaporin water channel

    DEFF Research Database (Denmark)

    Wu, Binghua; Steinbronn, Christina; Alsterfjord, Magnus

    2009-01-01

    Aquaporin (AQP) facilitated water transport is common to virtually all cell membranes and is marked by almost perfect specificity and high flux rates. Simultaneously, protons and cations are strictly excluded to maintain ionic transmembrane gradients. Yet, the AQP cation filters have not been...... identified experimentally. We report that three point mutations turned the water-specific AQP1 into a proton/alkali cation channel with reduced water permeability and the permeability sequence: H(+) >>K(+) >Rb(+) >Na(+) >Cs(+) >Li(+). Contrary to theoretical models, we found that electrostatic repulsion...... at the central asn-pro-ala (NPA) region does not suffice to exclude protons. Full proton exclusion is reached only in conjunction with the aromatic/arginine (ar/R) constriction at the pore mouth. In contrast, alkali cations are blocked by the NPA region but leak through the ar/R constriction. Expression...

  6. Working Paper 4: Institutions for Effective Water Demand ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2012-01-23

    Jan 23, 2012 ... Working Paper 4: Institutions for Effective Water Demand ... This working paper is part of WaDImena 's four Research Series on Water Demand Management ... Improving Water Demand Management Addressing Socioeconomic Inequalities and ... Women's rights and access to water and sanitation in Delhi.

  7. Fabrication of antibacterial water filter by coating silver nanoparticles on flexible polyurethane foams

    International Nuclear Information System (INIS)

    Nguyen Thi Phuong Phong; Ngo Vo Ke Thanh; Phan Hue Phuong

    2009-01-01

    In this paper, we fabricated silver-coated polyurethane foams and used it as a bacterial filter for contaminated drinking water. Flexible PU foams were soaked in silver colloidal solutions for 10 h, then washed and air-dried at room temperature. The prepared silver colloidal solutions and silver-coated PU materials were characterized by several techniques including TEM, FESEM/EDS, UV-VIS, ICP-AAS, and Raman spectroscopy. The TEM images showed that the size of silver nanoparticles in colloidal solutions varies from 6 to 12nm. The Raman, FE-SEM/EDS and ICP-AAS data illustrated that silver nanoparticles were stable on the PU foam and were not washed away by water. Furthermore, the microbiological tests (tube tests and flow test) were carried out on silver-coated PU materials with the Coliforms, E. coli, and B. subtilis. The obtained results showed that the bacteria was killed completely with antibacterial efficiency of 100% being observed. Our research suggests that silver-coated polyurethane foams can be used as excellent antibacterial water filters and would have several applications in other sectors.

  8. Comparison of filters for concentrating microbial indicators and pathogens in lake-water samples

    Science.gov (United States)

    Francy, Donna S.; Stelzer, Erin A.; Brady, Amie M.G.; Huitger, Carrie; Bushon, Rebecca N.; Ip, Hon S.; Ware, Michael W.; Villegas, Eric N.; Gallardo, Vincent; Lindquist, H.D. Alan

    2013-01-01

    Bacterial indicators are used to indicate increased health risk from pathogens and to make beach closure and advisory decisions; however, beaches are seldom monitored for the pathogens themselves. Studies of sources and types of pathogens at beaches are needed to improve estimates of swimming-associated health risks. It would be advantageous and cost-effective, especially for studies conducted on a regional scale, to use a method that can simultaneously filter and concentrate all classes of pathogens from the large volumes of water needed to detect pathogens. In seven recovery experiments, stock cultures of viruses and protozoa were seeded into 10-liter lake water samples, and concentrations of naturally occurring bacterial indicators were used to determine recoveries. For the five filtration methods tested, the highest median recoveries were as follows: glass wool for adenovirus (4.7%); NanoCeram for enterovirus (14.5%) and MS2 coliphage (84%); continuous-flow centrifugation (CFC) plus Virocap (CFC+ViroCap) for Escherichia coli (68.3%) and Cryptosporidium (54%); automatic ultrafiltration (UF) for norovirus GII (2.4%); and dead-end UF for Enterococcus faecalis (80.5%), avian influenza virus (0.02%), and Giardia (57%). In evaluating filter performance in terms of both recovery and variability, the automatic UF resulted in the highest recovery while maintaining low variability for all nine microorganisms. The automatic UF was used to demonstrate that filtration can be scaled up to field deployment and the collection of 200-liter lake water samples.

  9. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 1: nonuniform infiltration and soil water redistribution

    OpenAIRE

    Munoz Carpena, R.; Lauvernet, C.; Carluer, N.

    2018-01-01

    Vegetation buffers like vegetative filter strips (VFSs) are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT) that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To si...

  10. Role of electromagnetic filter in limitating radioactivity in the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    Dolle, L.

    1978-01-01

    High temperature electromagnetic filtration of particulate corrosion products can be carried out with discharges up to 5% of the cooling flow rate. It allows efficient extraction of particulate matter which rate constants required for considerable reduction of activable crud deposition in the core. The paper holds a review of the preventing operation in the primary circuit of a PWR, and reports experimental results of efficiency measurments with an electromagnetic filter set in out-of-pile and in-pile pressurized water loops. The notable efficiencies towards radioactive fine grain and colloidal matter justify more extensive reactor scale application experiments. (author)

  11. Role of electromagnetic filter in limitating radioactivity in the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    Dolle, L.

    1978-01-01

    High temperature electromagnetic filtration of particulate corrosion products can be carried out with discharges up to 5% of the cooling flow rate. It allows efficient extraction of particulate matter with rate constants required for considerable reduction of activable crud deposition in the core. The paper holds a review of the preventing operation in the primary circuit of a PWR, and reports experimental results of efficiency measurements with an electromagnetic filter set in out-of-pile and in-pile pressurized water loops. The notable efficiencies towards radioactive fine grain and colloidal matter justify more extensive reactor scale application experiments

  12. Processing Functional Near Infrared Spectroscopy Signal with a Kalman Filter to Assess Working Memory during Simulated Flight.

    Science.gov (United States)

    Durantin, Gautier; Scannella, Sébastien; Gateau, Thibault; Delorme, Arnaud; Dehais, Frédéric

    2015-01-01

    Working memory (WM) is a key executive function for operating aircraft, especially when pilots have to recall series of air traffic control instructions. There is a need to implement tools to monitor WM as its limitation may jeopardize flight safety. An innovative way to address this issue is to adopt a Neuroergonomics approach that merges knowledge and methods from Human Factors, System Engineering, and Neuroscience. A challenge of great importance for Neuroergonomics is to implement efficient brain imaging techniques to measure the brain at work and to design Brain Computer Interfaces (BCI). We used functional near infrared spectroscopy as it has been already successfully tested to measure WM capacity in complex environment with air traffic controllers (ATC), pilots, or unmanned vehicle operators. However, the extraction of relevant features from the raw signal in ecological environment is still a critical issue due to the complexity of implementing real-time signal processing techniques without a priori knowledge. We proposed to implement the Kalman filtering approach, a signal processing technique that is efficient when the dynamics of the signal can be modeled. We based our approach on the Boynton model of hemodynamic response. We conducted a first experiment with nine participants involving a basic WM task to estimate the noise covariances of the Kalman filter. We then conducted a more ecological experiment in our flight simulator with 18 pilots who interacted with ATC instructions (two levels of difficulty). The data was processed with the same Kalman filter settings implemented in the first experiment. This filter was benchmarked with a classical pass-band IIR filter and a Moving Average Convergence Divergence (MACD) filter. Statistical analysis revealed that the Kalman filter was the most efficient to separate the two levels of load, by increasing the observed effect size in prefrontal areas involved in WM. In addition, the use of a Kalman filter increased

  13. [Evaluation of drinking-water treatment by Lifestraw® and Ceramic-pot filters].

    Science.gov (United States)

    Pérez-Vidal, Andrea; Díaz-Gómez, Jaime; Salamanca-Rojas, Karen L; Rojas-Torres, Leidy Y

    2016-04-01

    Objective To evaluate under laboratory conditions, the removal efficiency of turbidity and E. coli of two household water filters: LifeStraw® family (MF) and ceramic pot filter (CPF). Methods The two systems were operated over 6 months using two identical control units per system, treating 7.5 L/d of a synthetic substrate used as raw water. The turbidity of the substrate was adjusted with Kaolinite and the E. coli concentration, with a replica of the ATCC 95922 strain. The differences of effluent quality of the systems, in terms of turbidity and E. coli, were evaluated with Analysis of Variance (ANOVA). Operative and maintenance aspects, that could limit or enhance the use of the systems, were also considered in the evaluation. Results The water synthetic substrate quality had an average of 32.2 ± 2.8 NTU for turbidity and 3,9x105 UFC/100 mL for E. coli. Both systems reduce the turbidity to values below 2 NTU with an inactivation of 100 % of E. coli. Statistical differences were found between the systems in terms of turbidity removal, MF being more efficient than the CPF (99,2 ± 0.4 % and 97.6 % ± 1.14, respectively). Conclusions Both systems are suitable for household water supply treatment, acheiving the water quality standards established by Colombian regulations. The MF was more efficient for suspended solids removal and filtration rate, but when economic, operative, and maintenance aspects along with social acceptability and lifespan are considered, the CPF seems more suitable, especially in rural areas.

  14. Evaluation of Plastic Household Biosand Filter (BSF) In Combination with Solar Disinfection (SODIS) For Water Treatment

    International Nuclear Information System (INIS)

    Hussain, G.; Haydar, S.; Bari, A. J.; Anis, M.; Asif, Z.; Aziz, J. A.

    2015-01-01

    Efficiency of a household plastic biosand filter (BSF) for the removal of turbidity and fecal contamination was evaluated. Water of river Ravi was used as influent. Water filtered through BSF was further treated using Solar Disinfection (SODIS). The study was conducted for raw water with low pollution level (total coliforms <500 MPN/100 ml) and high pollution level (total coliforms between 500-20,000 MPN/100 ml). The average value of turbidity removal by BSF was 94.5 percentage with 0.9 NTU as average turbidity of effluent. For raw water with low pollution level, the BSF was able to achieve a maximum of 2.2 log10 unit reduction (99.4 percentage) for total coliforms (39 MPN/100 mL in effluent) and 1.95 log10 unit reduction (98.5 percentage) for fecal coliforms (9 MPN/100 mL in effluent). While for raw water with high pollution level, the maximum removal of 1.5 log10 unit (97.5 percentage) for total coliforms (1430 MPN/100 mL in effluent) and 1.8 log10 units (98.4 percentage) for fecal coliforms (387 MPN/100 mL in effluent) was achieved in BSF. To make the effluent fit for drinking it was further treated using SODIS, which rendered the BSF effluent fit for drinking with zero fecal coliforms count (for full sunny and partially cloudy conditions). Newly proposed plastic BSF could be a good replacement of already used concrete household BSF (used in more than 63 countries) being cheaper in cost and lighter in weight by 85 percentage and 80 percentage, respectively than the concrete BSF. (author)

  15. Importance of copper for nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt

    nitrification during drinking water production provided the motivation to investigate if a lack of copper could be responsible for the problems in nitrifying biofilters. Copper is believed to be an essential cofactor in the enzyme ammonia monooxygenase (AMO), which catalyzes the first essential step...... be supplied in a controlled fashion, and that little maintenance and no chemicals are required. Copper dosing through the novel electrolysis method, as well as through passive dosing from solid copper and active dosing of copper solution, was studied at nine more DWTPs, which all shared a long history...... and chemical speciation modelling were carried out for Nærum DWTP. Results showed that substantial amounts of copper were bound to iron oxide-hydroxides in the filter and that bicarbonate heavily complexed copper in the water phase. Only total copper...

  16. A Method of Effective Quarry Water Purifying Using Artificial Filtering Arrays

    Science.gov (United States)

    Tyulenev, M.; Garina, E.; Khoreshok, A.; Litvin, O.; Litvin, Y.; Maliukhina, E.

    2017-01-01

    The development of open pit mining in the large coal basins of Russia and other countries increases their negative impact on the environment. Along with the damage of land and air pollution by dust and combustion gases of blasting, coal pits have a significant negative impact on water resources. Polluted quarry water worsens the ecological situation on a much larger area than covered by air pollution and land damage. This significantly worsens the conditions of people living in cities and towns located near the coal pits, and complicates the subsequent restoration of the environment, irreversibly destroying the nature. Therefore, the research of quarry wastewater purifying is becoming an important mater for scholars of technical colleges and universities in the regions with developing open-pit mining. This paper describes the method of determining the basic parameters of the artificial filtering arrays formed on coal pits of Kuzbass (Western Siberia, Russia), and gives recommendations on its application.

  17. Filter apparatus

    International Nuclear Information System (INIS)

    Butterworth, D.J.

    1980-01-01

    This invention relates to liquid filters, precoated by replaceable powders, which are used in the production of ultra pure water required for steam generation of electricity. The filter elements are capable of being installed and removed by remote control so that they can be used in nuclear power reactors. (UK)

  18. Explaining low rates of sustained use of siphon water filter: evidence from follow-up of a randomised controlled trial in Bangladesh.

    Science.gov (United States)

    Najnin, Nusrat; Arman, Shaila; Abedin, Jaynal; Unicomb, Leanne; Levine, David I; Mahmud, Minhaj; Leder, Karin; Yeasmin, Farzana; Luoto, Jill E; Albert, Jeff; Luby, Stephen P

    2015-04-01

    To assess sustained siphon filter usage among a low-income population in Bangladesh and study relevant motivators and barriers. After a randomised control trial in Bangladesh during 2009, 191 households received a siphon water filter along with educational messages. Researchers revisited households after 3 and 6 months to assess filter usage and determine relevant motivators and barriers. Regular users were defined as those who reported using the filter most of the time and were observed to be using the filter at follow-up visits. Integrated behavioural model for water, sanitation and hygiene (IBM-WASH) was used to explain factors associated with regular filter use. Regular filter usage was 28% at the 3-month follow-up and 21% at the 6-month follow-up. Regular filter users had better quality water at the 6-month, but not at the 3-month visit. Positive predictors of regular filter usage explained through IBM-WASH at both times were willingness to pay >US$1 for filters, and positive attitude towards filter use (technology dimension at individual level); reporting boiling drinking water at baseline (psychosocial dimension at habitual level); and Bengali ethnicity (contextual dimension at individual level). Frequently reported barriers to regular filter use were as follows: considering filter use an additional task, filter breakage and time required for water filtering (technology dimension at individual level). The technological, psychosocial and contextual dimensions of IBM-WASH contributed to understanding the factors related to sustained use of siphon filter. Given the low regular usage rate and the hardware-related problems reported, the contribution of siphon filters to improving water quality in low-income urban communities in Bangladesh is likely to be minimal. © 2014 John Wiley & Sons Ltd.

  19. Density and distribution of nitrifying guilds in rapid sand filters for drinking water production: Dominance of Nitrospira spp

    DEFF Research Database (Denmark)

    Tatari, Karolina; Musovic, Sanin; Gülay, Arda

    2017-01-01

    distribution of these guilds, filter material was sampled at four drinking water treatment plants (DWTPs) in parallel filters of the pre- and after-filtration stages at different locations and depths. The target guilds were quantified by qPCR targeting 16S rRNA and amoA genes. Total bacterial densities......We investigated the density and distribution of total bacteria, canonical Ammonia Oxidizing Bacteria (AOB) (Nitrosomonas plus Nitrosospira), Ammonia Oxidizing Archaea (AOA), as well as Nitrobacter and Nitrospira in rapid sand filters used for groundwater treatment. To investigate the spatial...

  20. Valuing water gains in the Eastern Cape's Working for Water ...

    African Journals Online (AJOL)

    drinie

    2002-01-01

    Jan 1, 2002 ... reason it is crucial that the pricing of this water be an accurate reflection of its relative ..... conservation projects, but it is not the best way of pricing water ... Establishment of a Pricing Strategy for Water Use Charges in Terms.

  1. Characterization of water commercial filters based on activated carbon for water treatment of the Tumbes river – Peru

    Directory of Open Access Journals (Sweden)

    Carmen Rosa Silupú García

    2017-09-01

    Full Text Available Comercial activated carbon samples (A, B, C, and D used in filters for the treatment of water were characterized and evaluated in the decontamination of heavy metals present in river water and in the elimination of coliform microorganisms. The carbon samples had microporous and mesoporous structures. Surface areas of between 705 and 906 m2/g were found. The carbons samples were amorphous and the presence of antibacterial agents such as Ag, Cl, Cu, and Si was detected. It was determined that for As and Pb, whose initial concentrations in contaminated water (water of the Tumbes river-Peru were 56.7 and 224.0 μg/L, respectively, the percentage of adsorption was close to 100%. The relationship between point of zero charge pH of the activated carbons and pH of the river water during the experiments plays a determinant role in the adsorption of the analyzed elements. The antibacterial capacity was evaluated satisfactorily against the following strains of fecal gram negative bacteria: Escherichia coli (ATCC® 25922™, Salmonella typhimurium (ATCC® 14028™, and Shigella flexneri (ATCC® 12022™. This ability is based on the surface presence in the carbons of the mentioned antibacterial agents.

  2. Bacterial diversity and active biomass in full-scale granular activated carbon filters operated at low water temperatures.

    Science.gov (United States)

    Kaarela, Outi E; Härkki, Heli A; Palmroth, Marja R T; Tuhkanen, Tuula A

    2015-01-01

    Granular activated carbon (GAC) filtration enhances the removal of natural organic matter and micropollutants in drinking water treatment. Microbial communities in GAC filters contribute to the removal of the biodegradable part of organic matter, and thus help to control microbial regrowth in the distribution system. Our objectives were to investigate bacterial community dynamics, identify the major bacterial groups, and determine the concentration of active bacterial biomass in full-scale GAC filters treating cold (3.7-9.5°C), physicochemically pretreated, and ozonated lake water. Three sampling rounds were conducted to study six GAC filters of different operation times and flow modes in winter, spring, and summer. Total organic carbon results indicated that both the first-step and second-step filters contributed to the removal of organic matter. Length heterogeneity analysis of amplified 16S rRNA genes illustrated that bacterial communities were diverse and considerably stable over time. α-Proteobacteria, β-Proteobacteria, and Nitrospira dominated in all of the GAC filters, although the relative proportion of dominant phylogenetic groups in individual filters differed. The active bacterial biomass accumulation, measured as adenosine triphosphate, was limited due to low temperature, low flux of nutrients, and frequent backwashing. The concentration of active bacterial biomass was not affected by the moderate seasonal temperature variation. In summary, the results provided an insight into the biological component of GAC filtration in cold water temperatures and the operational parameters affecting it.

  3. The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water

    Directory of Open Access Journals (Sweden)

    Glòria Carrasco-Turigas

    2013-01-01

    Full Text Available Disinfection by-products (DBPs are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4 (chloroform (TCM, bromodichloromethane (BDCM, dibromochloromethane (DBCM, and bromoform (TBM, MX, and bromate were tested when boiling and filtering high bromine-containing tap water from Barcelona. For filtering, we used a pitcher-type filter and a household reverse osmosis filter; for boiling, an electric kettle, a saucepan, and a microwave were used. Samples were taken before and after each treatment to determine the change in the DBP concentration. pH, conductivity, and free/total chlorine were also measured. A large decrease of THM4 (from 48% to 97% and MX concentrations was observed for all experiments. Bromine-containing trihalomethanes were mostly eliminated when filtering while chloroform when boiling. There was a large decrease in the concentration of bromate with reverse osmosis, but there was a little effect in the other experiments. These findings suggest that the exposure to THM4 and MX through ingestion is reduced when using these household appliances, while the decrease of bromate is device dependent. This needs to be considered in the exposure assessment of the epidemiological studies.

  4. Biologically active filters - An advanced water treatment process for contaminants of emerging concern.

    Science.gov (United States)

    Zhang, Shuangyi; Gitungo, Stephen W; Axe, Lisa; Raczko, Robert F; Dyksen, John E

    2017-05-01

    With the increasing concern of contaminants of emerging concern (CECs) in source water, this study examines the hypothesis that existing filters in water treatment plants can be converted to biologically active filters (BAFs) to treat these compounds. Removals through bench-scale BAFs were evaluated as a function of media, granular activated carbon (GAC) and dual media, empty bed contact time (EBCT), and pre-ozonation. For GAC BAFs, greater oxygen consumption, increased pH drop, and greater dissolved organic carbon removal normalized to adenosine triphosphate (ATP) were observed indicating increased microbial activity as compared to anthracite/sand dual media BAFs. ATP concentrations in the upper portion of the BAFs were as much as four times greater than the middle and lower portions of the dual media and 1.5 times greater in GAC. Sixteen CECs were spiked in the source water. At an EBCT of 18 min (min), GAC BAFs were highly effective with overall removals greater than 80% without pre-ozonation; exceptions included tri(2-chloroethyl) phosphate and iopromide. With a 10 min EBCT, the degree of CECs removal was reduced with less than half of the compounds removed at greater than 80%. The dual media BAFs showed limited CECs removal with only four compounds removed at greater than 80%, and 10 compounds were reduced by less than 50% with either EBCT. This study demonstrated that GAC BAFs with and without pre-ozonation are an effective and advanced technology for treating emerging contaminants. On the other hand, pre-ozonation is needed for dual media BAFs to remove CECs. The most cost effective operating conditions for dual media BAFs were a 10 min EBCT with the application of pre-ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Removal of turbidity and suspended solids backwash water from rapid sand filter by using electrocoagulation

    Directory of Open Access Journals (Sweden)

    AR Yari

    2016-07-01

    Full Text Available Introduction: By appropriate method can be recycled more than 95 percent effluent backwashing the filter. This study aimed to examine the efficiency of the electrocoagulation process on turbidity and suspended solids removal from backwash effluent of rapid sand filter of water treatment plants No 1 in Karaj. Methods: This bench-scale experimental study was carried out on the samples of backwash effluent in a batch system. The Plexiglas tank with a volume of 4 liters, containing of 4 plate electrodes made of aluminum and iron was connected to a direct current power supply. Samples every 15 minutes to measure turbidity and suspended solids collected in the middle of the reactor and examined. Effect of several parameters such as current density, reaction time and voltage were studied. The total number of samples tested were 48. Turbidity and total suspended solids was measured by nephlometry and gravimetric method, respectively. Results: The highest removal efficiency of turbidity and suspended solids in reaction time of 60 minutes, current density of 2 mA and a voltage of 45 mV was observed. The highest removal efficiency of turbidity in aluminum and iron electrodes were 96.83 and 83.77 %, respectively. Also The highest removal efficiency of suspended solids were 96.73 and 86.22 %, respectively. Conclusion: The results showed that electro- coagulation process can be a good choice to remove turbidity and suspended from backwash of rapid sand filter. Aluminum electrode efficiency in the removal of turbidity and suspended solids was greater than the iron electrode.

  6. Effect of Biological Contact Filters (BCFs on Membrane Fouling in Drinking Water Treatment Systems

    Directory of Open Access Journals (Sweden)

    Susumu Hasegawa

    2017-12-01

    Full Text Available Membrane fouling is a serious problem in drinking water treatment systems. Biological contact filters (BCFs are often used as a pretreatment to remove ammonia, dissolved organic matter (DOM, and metal ions such as iron and manganese. In this study, the effect of BCF as a pretreatment for membrane fouling was evaluated using a laboratory-scale mini module consisting of a mini BCF column and a mini MF column. Initially, it was confirmed that the main foulant was a biopolymer (at low concentration in the raw water. Subsequently, the biopolymer concentrations in the BCF influent and effluent were measured with the excitation emission matrix (EEM fluorescence spectroscopy and the liquid chromatograph organic carbon detector (LC-OCD. The fouling potential of the BCF influent and effluent was also measured to evaluate MF membrane fouling rate. The results demonstrate that application of the BCF reduced the biopolymer concentration of the effluent and reduced membrane fouling. The effect of BCF was also established in an actual drinking water treatment plant. It was found that optimizing the contact time of raw water with the BCF was crucial to reduce membrane fouling.

  7. Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water.

    Science.gov (United States)

    Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei

    2017-07-19

    An iron-manganese co-oxide filter film (MeO x ) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeO x was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeO x was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeO x included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeO x was formed by abiotic ways and the main elements on the surface of MeO x were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeO x as both ammonia molecules and ammonium ions and the active species of O₂ were possibly • O and O₂ - .

  8. Four-switch hybrid power filter working with six-fold switching symmetry

    Czech Academy of Sciences Publication Activity Database

    Klíma, J.; Tlustý, J.; Škramlík, Jiří; Valouch, Viktor

    2011-01-01

    Roč. 56, č. 4 (2011), s. 433-446 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : component minimized hybrid power filter * control strategy * analytical model Subject RIV: JA - Electronics ; Optoelectronics, Electric al Engineering

  9. Analytical Modeling and Simulation of Four-Switch Hybrid Power Filter Working with Sixfold Switching Symmetry

    Czech Academy of Sciences Publication Activity Database

    Tlustý, J.; Škramlík, Jiří; Švec, J.; Valouch, Viktor

    2012-01-01

    Roč. 2012, č. 292178 (2012), s. 1-17 ISSN 1024-123X Institutional support: RVO:61388998 Keywords : analytical modeling * four-switch hybrid power filter * sixfold switching symmetry Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.383, year: 2012 http://www.hindawi.com/journals/mpe/2012/292178/

  10. Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems

    DEFF Research Database (Denmark)

    Ibrom, Andreas; Dellwik, Ebba; Flyvbjerg, Henrik K.

    2007-01-01

    datasets for this substantial measurement error. In contrast to earlier studies, a large number of spectra and raw data have been used in the analysis to define the low-pass filtering characteristic of the EC system. This revealed that the cut-off frequency of the closed-path EC system for water vapour......Turbulent water vapour fluxes measured with closed-path eddy correlation (EC) systems are unintentionally low-pass filtered by the system in a manner that varies with environmental conditions. Why and how is described here. So is the practical method that systematically corrects long-term flux...... concentration measurements decreases exponentially with increasing relative humidity. After correction for this unintended filtering, the fluxes are consistent with CO2 and H2O fluxes that were measured with an open-path sensor at the same time. The correction of water vapour flux measurements over a Beech...

  11. The potential of PIXE analytical work in water pollution

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, H.; Takahashi, Y.; Ishii, K. [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi (JP)] [and others

    1999-07-01

    A method has been developed and tested for PIXE analysis of soluble and insoluble constituents in a variety of water samples in our surroundings. Insoluble components were filtered on a Nuclepore filter of 0.4-{mu}m pores. For soluble fractions, a target of major components was made from a 0.15-ml filtrate evaporated on a user-made polycarbonate film, and in turn heavy metals in trace amounts were preconcentrated in a PIXE-target through the use of a combination of dibenzyldithiocarbamate-chelation with subsequent condensation into dibenzylidene-D-sorbitol gels. These three kinds of targets were analyzed with a PIXE system of 3-MeV proton beams. The widespread concentrations (several tenths of ppb to a few tens of ppm) of {approx}24 elements from Na to Pb were determined simultaneously in a precision sufficient to reveal the elemental distribution between the soluble and insoluble fractions of various aqueous sample such as river water, rain water and water leaking from disposal sites of industrial wastes. Hence, the methodology for preparing three types of targets promotes the PIXE analysis to a truly effective means for monitoring a water-pollution problem in our surroundings. (author)

  12. The potential of PIXE analytical work in water pollution

    International Nuclear Information System (INIS)

    Yamazaki, H.; Takahashi, Y.; Ishii, K.

    1999-01-01

    A method has been developed and tested for PIXE analysis of soluble and insoluble constituents in a variety of water samples in our surroundings. Insoluble components were filtered on a Nuclepore filter of 0.4-μm pores. For soluble fractions, a target of major components was made from a 0.15-ml filtrate evaporated on a user-made polycarbonate film, and in turn heavy metals in trace amounts were preconcentrated in a PIXE-target through the use of a combination of dibenzyldithiocarbamate-chelation with subsequent condensation into dibenzylidene-D-sorbitol gels. These three kinds of targets were analyzed with a PIXE system of 3-MeV proton beams. The widespread concentrations (several tenths of ppb to a few tens of ppm) of ∼24 elements from Na to Pb were determined simultaneously in a precision sufficient to reveal the elemental distribution between the soluble and insoluble fractions of various aqueous sample such as river water, rain water and water leaking from disposal sites of industrial wastes. Hence, the methodology for preparing three types of targets promotes the PIXE analysis to a truly effective means for monitoring a water-pollution problem in our surroundings. (author)

  13. Study on Water Quality of Surface Runoff and Groundwater Runoff on the Basis of Separation by a Numerical Filter

    OpenAIRE

    Kawara, Osami; Fukumoto, Kohji

    1994-01-01

    In this study we investigated the water quality of surface runoff and groundwater runoff from the basins of the Yodo River and the Asahi River based on that separated by a numerical filter. The water quality of the surface runoff is greatly different from the groundwater runoff. The tendency of concentration change in accordance with river discharges is different from each other. The water qtiality of groundwater runoff changes with river discharges clockwise in many cases. The differences of...

  14. Research of preferences of consumers of household filters for water purification by the fokus-grupp method

    OpenAIRE

    Medvedeva, E.; Blyumina, A.; Piskunov, V.

    2013-01-01

    Availability of qualitative water - the minimum guarantee of health of the person water or to use it only for cleaning and ware washing. The growing demand and change of consumer preferences causes relevance and timeliness of the organization and carrying out the research "Consumer Behaviour in the Market of Household Filters for Water Purification". As the main instrument of obtaining information the method of focus groups was chosen. In article criteria of a consumer choice are defined, to ...

  15. Ground water work breakdown structure dictionary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    This report contains the activities that are necessary to assess in ground water remediation as specified in the UMTRA Project. These activities include the following: site characterization; remedial action compliance and design documentation; environment, health, and safety program; technology assessment; property access and acquisition activities; site remedial actions; long term surveillance and licensing; and technical and management support.

  16. Ground water work breakdown structure dictionary

    International Nuclear Information System (INIS)

    1995-04-01

    This report contains the activities that are necessary to assess in ground water remediation as specified in the UMTRA Project. These activities include the following: site characterization; remedial action compliance and design documentation; environment, health, and safety program; technology assessment; property access and acquisition activities; site remedial actions; long term surveillance and licensing; and technical and management support

  17. Evaluation of filters in RSPCS (Reactor Service Pool Cooling System) and HWL (Hot Water Layer) in OPAL research reactor at ANSTO (Australian Nuclear Science and Technology Organization) using Gamma Spectrometry System and Liquid Scintillation Counter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jim In; Foy, Robin; Jung, Seong Moon; Park, Hyeon Suk; Ye, Sung Joon [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Australian Nuclear Science and Technology Organization(ANSTO) has a research reactor, OPAL (Open Pool Australian Lightwater reactor) which is a state-of-art 20 MW reactor for various purposes. In OPAL reactor, there are many kinds of radionuclides produced from various reactions in pool water and those should be identified and quantified for the safe use of OPAL. To do that, it is essential to check the efficiency of filters which are able to remove the radioactive substance from the reactor pool water. There are two main water circuits in OPAL which are RSPCS (Reactor Service Pool Cooling System) and HWL (Hot Water Layer) water circuits. The reactor service pool is connected to the reactor pool via a transfer canal and provides a working area and storage space for the spent and other materials. Also, HWL is the upper part of the reactor pool water and it minimize radiation dose rates at the pool surface. We collected water samples from these circuits and measured the radioactivity by using Gamma Spectrometry System (GSS) and Liquid Scintillation Counter (LSC) to evaluate the filters. We could evaluate the efficiency of filters in RSPCS and HWL in OPAL research reactor. Through the measurements of radioactivity using GSS and LSC, we could conclude that there is likely to be no alpha emitter in water samples, and for beta and gamma activity, there are very big differences between inlet and outlet results, so every filter is working efficiently to remove the radioactive substance.

  18. Depth investigation of rapid sand filters for drinking water production reveals strong stratification in nitrification biokinetic behavior

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Albrechtsen, Hans-Jørgen

    2016-01-01

    The biokinetic behavior of NH4 + removal was investigated at different depths of a rapid sand filter treating groundwater for drinking water preparation. Filter materials from the top, middle and bottom layers of a full-scale filter were exposed to various controlled NH4 + loadings in a continuous......-flow lab-scale assay. NH4 + removal capacity, estimated from short term loading up-shifts, was at least 10 times higher in the top than in the middle and bottom filter layers, consistent with the stratification of Ammonium Oxidizing Bacteria (AOB). AOB density increased consistently with the NH4 + removal...... rate, indicating their primarily role in nitrification under the imposed experimental conditions. The maximum AOB cell specific NH4 + removal rate observed at the bottom was at least 3 times lower compared to the top and middle layers. Additionally, a significant up-shift capacity (4.6 and 3.5 times...

  19. Convergent Filter Bases

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  20. Use of self cleaning filters as pre-filter in water injection for maintenance of fine filters life; Uso de filtros auto limpantes como pre-filtro em agua de injecao para manutencao da vida util dos filtros polidores

    Energy Technology Data Exchange (ETDEWEB)

    Ramalhao, Adriano Gorga; Seno, Carlos Eduardo; Ribeiro, Alice [3M do Brasil Ltda., Sumare, SP (Brazil)

    2008-07-01

    The water injection treatment involves several units of treatment, which are defined and designed from data, some obtained from measurements, with other empirical formulas, others as a compromise, and that most of them varies. This variability can be covered by some filtration systems with greater flexibility. In the case of self cleaning filtration systems, they offer such flexibility due to its retro washing automated by metal cartridges that can extend up to fifty percent in the life of the filter end in cases of deterioration in water quality because of increased organic material for many reasons. (author)

  1. Predation and transport of persistent pathogens in GAC and slow sand filters: a threat to drinking water safety?

    Science.gov (United States)

    Bichai, Françoise; Dullemont, Yolanda; Hijnen, Wim; Barbeau, Benoit

    2014-11-01

    Zooplankton has been shown to transport internalized pathogens throughout engineered drinking water systems. In this study, experimental measurements from GAC and SSF filtration tests using high influent concentrations of Cryptosporidium (1.3 × 10(6) and 3.3 × 10(4) oocysts L(-1)) and Giardia (4.8 × 10(4) cysts L(-1)) are presented and compared. A predation and transport conceptual model was developed to extrapolate these results to environmental conditions of typical (oo)cyst concentrations in surface water in order to predict concentrations of internalized (oo)cysts in filtered water. Pilot test results were used to estimate transport and survival ratios of internalized (oo)cysts following predation by rotifers in the filter beds. Preliminary indications of lower transport and survival ratios in SSF were found as compared with GAC filters. A probability of infection due to internalized (oo)cysts in filtered water was calculated under likeliest environmental conditions and under a worst-case scenario. Estimated risks under the likeliest environmental scenario were found to fall below the tolerable risk target of 10(-4) infections per person per year. A discussion is presented on the health significance of persistent pathogens that are internalized by zooplankton during granular filtration processes and released into treated water. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Application of design for six sigma methodology on portable water filter that uses membrane filtration system: A preliminary study

    Science.gov (United States)

    Fahrul Hassan, Mohd; Jusoh, Suhada; Zaini Yunos, Muhamad; Arifin, A. M. T.; Ismail, A. E.; Rasidi Ibrahim, M.; Zulafif Rahim, M.

    2017-09-01

    Portable water filter has grown significantly in recent years. The use of water bottles as a water drink stuff using hand pump water filtration unit has been suggested to replace water bottled during outdoor recreational activities and for emergency supplies. However, quality of water still the issue related to contaminated water due to the residual waste plants, bacteria, and so on. Based on these issues, the study was carried out to design a portable water filter that uses membrane filtration system by applying Design for Six Sigma. Design for Six Sigma methodology consists of five stages which is Define, Measure, Analyze, Design and Verify. There were several tools have been used in each stage in order to come out with a specific objective. In the Define stage, questionnaire approach was used to identify the needs of portable water filter in the future from potential users. Next, Quality Function Deployment (QFD) tool was used in the Measure stage to measure the users’ needs into engineering characteristics. Based on the information in the Measure stage, morphological chart and weighted decision matrix tools were used in the Analyze stage. This stage performed several activities including concept generation and selection. Once the selection of the final concept completed, detail drawing was made in the Design stage. Then, prototype was developed in the Verify stage to conduct proof-of-concept testing. The results that obtained from each stage have been reported in this paper. From this study, it can be concluded that the application of Design for Six Sigma in designing a future portable water filter that uses membrane filtration system is a good start in looking for a new alternative concept with a completed supporting document.

  3. A comparison study of the start-up of a MnOx filter for catalytic oxidative removal of ammonium from groundwater and surface water.

    Science.gov (United States)

    Cheng, Ya; Li, Ye; Huang, Tinglin; Sun, Yuankui; Shi, Xinxin; Shao, Yuezong

    2018-03-01

    As an efficient method for ammonium (NH 4 + ) removal, contact catalytic oxidation technology has drawn much attention recently, due to its good low temperature resistance and short start-up period. Two identical filters were employed to compare the process for ammonium removal during the start-up period for ammonium removal in groundwater (Filter-N) and surface water (Filter-S) treatment. Two types of source water (groundwater and surface water) were used as the feed waters for the filtration trials. Although the same initiating method was used, Filter-N exhibited much better ammonium removal performance than Filter-S. The differences in catalytic activity among these two filters were probed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and compositional analysis. XRD results indicated that different manganese oxide species were formed in Filter-N and Filter-S. Furthermore, the Mn3p XPS spectra taken on the surface of the filter films revealed that the average manganese valence of the inactive manganese oxide film collected from Filter-S (FS-MnO x ) was higher than in the film collected from Filter-N (FN-MnO x ). Mn(IV) was identified as the predominant oxidation state in FS-MnO x and Mn(III) was identified as the predominant oxidation state in FN-MnO x . The results of compositional analyses suggested that polyaluminum ferric chloride (PAFC) used during the surface water treatment was an important factor in the mineralogy and reactivity of MnO x . This study provides the theoretical basis for promoting the wide application of the technology and has great practical significance. Copyright © 2017. Published by Elsevier B.V.

  4. 75 FR 20352 - National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting...

    Science.gov (United States)

    2010-04-19

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9139-3] National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting Announcement AGENCY: Environmental Protection Agency. ACTION...-person meeting of the Climate Ready Water Utilities (CRWU) Working Group of the National Drinking Water...

  5. 75 FR 1380 - National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting...

    Science.gov (United States)

    2010-01-11

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9101-9] National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting Announcement AGENCY: Environmental Protection Agency. ACTION... meeting of the Climate Ready Water Utilities (CRWU) Working Group of the National Drinking Water Advisory...

  6. Sphagnum can 'filter' N deposition, but effects on the plant and pore water depend on the N form.

    Science.gov (United States)

    Chiwa, Masaaki; Sheppard, Lucy J; Leith, Ian D; Leeson, Sarah R; Tang, Y Sim; Cape, J Neil

    2016-07-15

    The ability of Sphagnum moss to efficiently intercept atmospheric nitrogen (N) has been assumed to be vulnerable to increased N deposition. However, the proposed critical load (20kgNha(-1)yr(-1)) to exceed the capacity of the Sphagnum N filter has not been confirmed. A long-term (11years) and realistic N manipulation on Whim bog was used to study the N filter function of Sphagnum (Sphagnum capillifolium) in response to increased wet N deposition. On this ombrotrophic peatland where ambient deposition was 8kgNha(-1)yr(-1), an additional 8, 24, and 56kgNha(-1)yr(-1) of either ammonium (NH4(+)) or nitrate (NO3(-)) has been applied for 11years. Nutrient status of Sphagnum and pore water quality from the Sphagnum layer were assessed. The N filter function of Sphagnum was still active up to 32kgNha(-1)yr(-1) even after 11years. N saturation of Sphagnum and subsequent increases in dissolved inorganic N (DIN) concentration in pore water occurred only for 56kgNha(-1)yr(-1) of NH4(+) addition. These results indicate that the Sphagnum N filter is more resilient to wet N deposition than previously inferred. However, functionality will be more compromised when NH4(+) dominates wet deposition for high inputs (56kgNha(-1)yr(-1)). The N filter function in response to NO3(-) uptake increased the concentration of dissolved organic N (DON) and associated organic anions in pore water. NH4(+) uptake increased the concentration of base cations and hydrogen ions in pore water though ion exchange. The resilience of the Sphagnum N filter can explain the reported small magnitude of species change in the Whim bog ecosystem exposed to wet N deposition. However, changes in the leaching substances, arising from the assimilation of NO3(-) and NH4(+), may lead to species change. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Water: The Flow of Women's Work. Water in Africa.

    Science.gov (United States)

    Cohen, Amy

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers, World Wise Schools (WWS) classroom teachers, and WWS staff members. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning…

  8. Critical parameters in the production of ceramic pot filters for household water treatment in developing countries.

    Science.gov (United States)

    Soppe, A I A; Heijman, S G J; Gensburger, I; Shantz, A; van Halem, D; Kroesbergen, J; Wubbels, G H; Smeets, P W M H

    2015-06-01

    The need to improve the access to safe water is generally recognized for the benefit of public health in developing countries. This study's objective was to identify critical parameters which are essential for improving the performance of ceramic pot filters (CPFs) as a point-of-use water treatment system. Defining critical production parameters was also relevant to confirm that CPFs with high-flow rates may have the same disinfection capacity as pots with normal flow rates. A pilot unit was built in Cambodia to produce CPFs under controlled and constant conditions. Pots were manufactured from a mixture of clay, laterite and rice husk in a small-scale, gas-fired, temperature-controlled kiln and tested for flow rate, removal efficiency of bacteria and material strength. Flow rate can be increased by increasing pore sizes and by increasing porosity. Pore sizes were increased by using larger rice husk particles and porosity was increased with larger proportions of rice husk in the clay mixture. The main conclusions: larger pore size decreases the removal efficiency of bacteria; higher porosity does not affect the removal efficiency of bacteria, but does influence the strength of pots; flow rates of CPFs can be raised to 10-20 L/hour without a significant decrease in bacterial removal efficiency.

  9. Assimilation of lake water surface temperature observations using an extended Kalman filter

    Directory of Open Access Journals (Sweden)

    Ekaterina Kourzeneva

    2014-10-01

    Full Text Available A new extended Kalman filter (EKF-based algorithm to assimilate lake water surface temperature (LWST observations into the lake model/parameterisation scheme Freshwater Lake (FLake has been developed. The data assimilation algorithm has been implemented into the stand-alone offline version of FLake. The mixed and non-mixed regimes in lakes are treated separately by the EKF algorithm. The timing of the ice period is indicated implicitly: no ice if water surface temperature is measured. Numerical experiments are performed using operational in-situ observations for 27 lakes and merged observations (in-situ plus satellite for 4 lakes in Finland. Experiments are analysed, potential problems are discussed, and the role of early spring observations is studied. In general, results of experiments are promising: (1 the impact of observations (calculated as the normalised reduction of the LWST root mean square error comparing to the free model run is more than 90% and (2 in cross-validation (when observations are partly assimilated, partly used for validation the normalised reduction of the LWST error standard deviation is more than 65%. The new data assimilation algorithm will allow prognostic variables in the lake parameterisation scheme to be initialised in operational numerical weather prediction models and the effects of model errors to be corrected by using LWST observations.

  10. Optimization of an enhanced ceramic micro-filter for concentrating E.coli in water

    Science.gov (United States)

    Zhang, Yushan; Guo, Tianyi; Xu, Changqing; Hong, Lingcheng

    2017-02-01

    Recently lower limit of detection (LOD) is necessary for rapid bacteria detection and analysis applications in clinical practices and daily life. A critical pre-conditioning step for these applications is bacterial concentration, especially for low level of pathogens. Sample volume can be largely reduced with an efficient pre-concentration process. Some approaches such as hollow-fiber ultra-filtration and electrokinetic technique have been applied to bacterial concentration. Since none of these methods can provide a concentrating method with a stable recovery efficiency, bacterial concentration still remains challenging Ceramic micro- filter can be used to concentrate the bacteria but the cross flow system keeps the bacteria in suspension. Similar harvesting bacteria using ultra-filtration showed an average recovery efficiency of 43% [1] and other studies achieved recovery rates greater than 50% [2]. In this study, an enhanced ceramic micro-filter with 0.14 μm pore size was proposed and demonstrated to optimize the concentration of E.coli. A high recovery rate (mean value >90%) and a high volumetric concentration ratio (>100) were achieved. Known quantities (104 to 106 CFU/ml) of E.coli cells were spiked to different amounts of phosphate buffered saline (0.1 to 1 L), and then concentrated to a final retentate of 5 ml to 10 ml. An average recovery efficiency of 95.3% with a standard deviation of 5.6% was achieved when the volumetric con- centration ratio was 10. No significant recovery rate loss was indicated when the volumetric concentration ratio reached up to 100. The effects of multiple parameters on E.coli recovery rate were also studied. The obtained results indicated that the optimized ceramic micro- filtration system can successfully concentrate E.coli cells in water with an average recovery rate of 90.8%.

  11. Polaromonas and Hydrogenophaga species are the predominant bacteria cultured from granular activated carbon filters in water treatment

    NARCIS (Netherlands)

    Magic-Knezev, A.; Wullings, B.A.; Kooij, van der D.

    2009-01-01

    AIM: Identification of the predominating cultivable bacteria in granular activated carbon (GAC) filters used in a variety of water treatment plants for selecting representative strains to study the role of bacteria in the removal of dissolved organic matter. METHODS AND RESULTS: Bacterial isolates

  12. Retention of titanium dioxide nanoparticles in biological activated carbon filters for drinking water and the impact on ammonia reduction.

    Science.gov (United States)

    Liu, Zhiyuan; Yu, Shuili; Park, Heedeung; Liu, Guicai; Yuan, Qingbin

    2016-06-01

    Given the increasing discoveries related to the eco-toxicity of titanium dioxide (TiO2) nanoparticles (NPs) in different ecosystems and with respect to public health, it is important to understand their potential effects in drinking water treatment (DWT). The effects of TiO2 NPs on ammonia reduction, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in biological activated carbon (BAC) filters for drinking water were investigated in static and dynamic states. In the static state, both the nitrification potential and AOB were significantly inhibited by 100 μg L(-1) TiO2 NPs after 12 h (p  0.05). In the dynamic state, different amounts of TiO2 NP pulses were injected into three pilot-scale BAC filters. The decay of TiO2 NPs in the BAC filters was very slow. Both titanium quantification and scanning electron microscope analysis confirmed the retention of TiO2 NPs in the BAC filters after 134 days of operation. Furthermore, the TiO2 NP pulses considerably reduced the performance of ammonia reduction. This study identified the retention of TiO2 NPs in BAC filters and the negative effect on the ammonia reduction, suggesting a potential threat to DWT by TiO2 NPs.

  13. 3D soil water nowcasting using electromagnetic conductivity imaging and the ensemble Kalman filter

    Science.gov (United States)

    Huang, Jingyi; McBratney, Alex B.; Minasny, Budiman; Triantafilis, John

    2017-06-01

    Mapping and immediate forecasting of soil water content (θ) and its movement can be challenging. Although inversion of apparent electrical conductivity (ECa) measured by electromagnetic induction to calculate depth-specific electrical conductivity (σ) has been used, it is difficult to apply it across a field. In this paper we use a calibration established along a transect, across a 3.94-ha field with varying soil texture, using an ensemble Kalman filter (EnKF) to monitor and nowcast the 3-dimensional θ dynamics on 16 separate days over a period of 38 days. The EnKF combined a physical model fitted with θ measured by soil moisture sensors and an Artificial Neural Network model comprising σ generated by quasi-3d inversions of DUALEM-421S ECa data. Results showed that the distribution of θ was controlled by soil texture, topography, and vegetation. Soil water dried fastest at the beginning after the initial irrigation event and decreased with time and soil depth, which was consistent with classical soil drying theory and experiments. It was also found that the soil dried fastest in the loamy and duplex soils present in the field, which was attributable to deep drainage and preferential flow. It was concluded that the EnKF approach can be used to improve the irrigation efficiency by applying variable irrigation rates across the field. In addition, soil water status can be nowcasted across large spatial extents using this method with weather forecast information, which will provide guidance to farmers for real-time irrigation management.

  14. Water-filtered infrared a irradiation in combination with visible light inhibits acute chlamydial infection.

    Directory of Open Access Journals (Sweden)

    Hanna Marti

    Full Text Available New therapeutic strategies are needed to overcome drawbacks in treatment of infections with intracellular bacteria. Chlamydiaceae are Gram-negative bacteria implicated in acute and chronic diseases such as abortion in animals and trachoma in humans. Water-filtered infrared A (wIRA is short wavelength infrared radiation with a spectrum ranging from 780 to 1400 nm. In clinical settings, wIRA alone and in combination with visible light (VIS has proven its efficacy in acute and chronic wound healing processes. This is the first study to demonstrate that wIRA irradiation combined with VIS (wIRA/VIS diminishes recovery of infectious elementary bodies (EBs of both intra- and extracellular Chlamydia (C. in two different cell lines (Vero, HeLa regardless of the chlamydial strain (C. pecorum, C. trachomatis serovar E as shown by indirect immunofluorescence and titration by subpassage. Moreover, a single exposure to wIRA/VIS at 40 hours post infection (hpi led to a significant reduction of C. pecorum inclusion frequency in Vero cells and C. trachomatis in HeLa cells, respectively. A triple dose of irradiation (24, 36, 40 hpi during the course of C. trachomatis infection further reduced chlamydial inclusion frequency in HeLa cells without inducing the chlamydial persistence/stress response, as ascertained by electron microscopy. Irradiation of host cells (HeLa, Vero neither affected cell viability nor induced any molecular markers of cytotoxicity as investigated by Alamar blue assay and Western blot analysis. Chlamydial infection, irradiation, and the combination of both showed a similar release pattern of a subset of pro-inflammatory cytokines (MIF/GIF, Serpin E1, RANTES, IL-6, IL-8 and chemokines (IL-16, IP-10, ENA-78, MIG, MIP-1α/β from host cells. Initial investigation into the mechanism indicated possible thermal effects on Chlamydia due to irradiation. In summary, we demonstrate a non-chemical reduction of chlamydial infection using the combination

  15. Estimation of pressure drop in the mixing zone of beds in operation filters as drinking water treatment by a mathematical model

    International Nuclear Information System (INIS)

    Rodriguez Miranda, J. P.

    2010-01-01

    This paper describes the correlation of a mathematical model that considers the pressure drop (energy) in the mixing zone of beds in operation filters as drinking water treatment, filters applied in conventional pilot operated and mounted on a water treatment plant of a municipally in Colombia. (Author) 20 refs.

  16. Neural correlate of filtering of irrelevant information from visual working memory.

    Science.gov (United States)

    Nasr, Shahin; Moeeny, Ali; Esteky, Hossein

    2008-09-26

    In a dynamic environment stimulus task relevancy could be altered through time and it is not always possible to dissociate relevant and irrelevant objects from the very first moment they come to our sight. In such conditions, subjects need to retain maximum possible information in their WM until it is clear which items should be eliminated from WM to free attention and memory resources. Here, we examined the neural basis of irrelevant information filtering from WM by recording human ERP during a visual change detection task in which the stimulus irrelevancy was revealed in a later stage of the task forcing the subjects to keep all of the information in WM until test object set was presented. Assessing subjects' behaviour we found that subjects' RT was highly correlated with the number of irrelevant objects and not the relevant one, pointing to the notion that filtering, and not selection, process was used to handle the distracting effect of irrelevant objects. In addition we found that frontal N150 and parietal N200 peak latencies increased systematically as the amount of irrelevancy load increased. Interestingly, the peak latency of parietal N200, and not frontal N150, better correlated with subjects' RT. The difference between frontal N150 and parietal N200 peak latencies varied with the amount of irrelevancy load suggesting that functional connectivity between modules underlying fronto-parietal potentials vary concomitant with the irrelevancy load. These findings suggest the existence of two neural modules, responsible for irrelevant objects elimination, whose activity latency and functional connectivity depend on the number of irrelevant object.

  17. Neural correlate of filtering of irrelevant information from visual working memory.

    Directory of Open Access Journals (Sweden)

    Shahin Nasr

    Full Text Available In a dynamic environment stimulus task relevancy could be altered through time and it is not always possible to dissociate relevant and irrelevant objects from the very first moment they come to our sight. In such conditions, subjects need to retain maximum possible information in their WM until it is clear which items should be eliminated from WM to free attention and memory resources. Here, we examined the neural basis of irrelevant information filtering from WM by recording human ERP during a visual change detection task in which the stimulus irrelevancy was revealed in a later stage of the task forcing the subjects to keep all of the information in WM until test object set was presented. Assessing subjects' behaviour we found that subjects' RT was highly correlated with the number of irrelevant objects and not the relevant one, pointing to the notion that filtering, and not selection, process was used to handle the distracting effect of irrelevant objects. In addition we found that frontal N150 and parietal N200 peak latencies increased systematically as the amount of irrelevancy load increased. Interestingly, the peak latency of parietal N200, and not frontal N150, better correlated with subjects' RT. The difference between frontal N150 and parietal N200 peak latencies varied with the amount of irrelevancy load suggesting that functional connectivity between modules underlying fronto-parietal potentials vary concomitant with the irrelevancy load. These findings suggest the existence of two neural modules, responsible for irrelevant objects elimination, whose activity latency and functional connectivity depend on the number of irrelevant object.

  18. Drying of heavy water system and works of charging heavy water in Fugen

    International Nuclear Information System (INIS)

    Matsushita, Tadashi; Iijima, Setsuo

    1980-01-01

    The advanced thermal reactor ''Fugen'' is the first heavy water-moderated, boiling light water-cooled nuclear reactor for power generation in Japan. It is a large heavy water reactor having about 130 m 3 of heavy water inventory and about 300 m 3 of helium space as the cover gas of the heavy water system. The heavy water required was purchased from FRG, which had been used for the power output test in the KKN, and the quality was 99.82 mol % mean heavy water concentration. The concentration of heavy water for Fugen used for the nuclear design is 99.70 mol%, and it was investigated how heavy water can be charged without lowering the concentration. The matters of investigation include the method of bringing the heavy water and helium system to perfect dryness after washing and light water test, the method of confirming the sufficient dryness to prevent the deterioration, and the method of charging heavy water safely from its containers. On the basis of the results of investigation, the actual works were started. The works of drying the heavy water and helium system by vacuum drying, the works of sampling heavy water and the result of the degree of deterioration, and the works of charging heavy water and the measures to the heavy water remaing in the containers are described. All the works were completed safely and smoothly. (J.P.N.)

  19. The Nano-filters as the tools for the management of the water imbalance in the human society

    Science.gov (United States)

    Singh, R. P.; Kontar, V.

    2011-12-01

    ultra-thin nanoscale fibers, which filter out contaminants, plus active carbon granules, which kill bacteria. The carbon nano-tube as filters exhibit chemical-species selectivity with higher physical strength and higher temperature tolerance, more rugged process, more rapid filtration, regeneration via thermal means rather than physical removal and lowers costs. The nano-filters remove the toxic or unwanted bivalent ions (ions with 2 or more charges), such as lead, iron, nickel, mercury, etc. The nano-materials and nano-filters will help solve the problems of the water imbalance management in the human society. Therefore we are talking about some nano-applications on the session H138 "Imbalance of Water in Nature".

  20. Control of spatial xenon oscillations in pressurized water reactors via the Kalman filter

    International Nuclear Information System (INIS)

    Lin, C.; Lin, Y.J.

    1994-01-01

    A direct control method is developed to control the spatial xenon oscillations in pressurized water reactors. The xenon and iodine concentration difference between the top and bottom halves of the core is estimated by using the extended Kalman filter (EKF), which is a closed-loop estimation method. The measurement equation used in the observer is the axial offset measurement equation, which reflects the xenon unbalanced effect on the axial offset. Meanwhile, some of the coefficients of the observer are estimated on-line to reduce estimation error resulting from model error, i.e., simplified xenon and iodine dynamics. Therefore, the estimation can be guaranteed to be accurate, and the success of the estimation does not greatly depend on the accuracy of the observer model. The predicted one-step ahead xenon concentration, by using the EKF, was used to calculate the possible axial offset variation, and then the control rod motion was calculated to compensate for it. The simulation results show that the proposed method successfully controls the xenon oscillations

  1. 75 FR 54871 - National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting...

    Science.gov (United States)

    2010-09-09

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9198-8] National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting Announcement AGENCY: Environmental Protection Agency (EPA... final in-person meeting of the Climate Ready Water Utilities (CRWU) Working Group of the National...

  2. 75 FR 35458 - National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting...

    Science.gov (United States)

    2010-06-22

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9165-6] National Drinking Water Advisory Council's Climate Ready Water Utilities Working Group Meeting Announcement AGENCY: Environmental Protection Agency (EPA... fourth in-person meeting of the Climate Ready Water Utilities (CRWU) Working Group of the National...

  3. A rapid two dot filter assay for the detection of E. coli O157 in water samples.

    Science.gov (United States)

    Kamma, Sujatha; Tang, Lily; Leung, Kelvin; Ashton, Edie; Newman, Norman; Suresh, Mavanur R

    2008-07-31

    E. coli O157:H7 is an enterohemorrhagic bacteria that cause deadly water-borne infections implicated in outbreaks of a wide spectrum of human gastrointestinal diseases. It is therefore important to have a rapid convenient, simple and sensitive range of detection of E. coli O157:H7. A new E. coli O157 MAb designated P124 was developed for ultrasensitive detection of E. coli O157 in water, apple juice and beef for routine use. A prototype filter dot assay was designed with anti-E. coli O157 MAb bound to 0.2 microm nitrocellulose filter disk as the capture antibody. A 100 ml water sample spiked with 1-50 CFU of E. coli O157 either in the presence or absence of other non-specific bacteria were filtered for capture of the pathogen on the antibody coated nitrocellulose disk. The detection of the pathogen was successfully accomplished by the same antibody both as a capture and detecting antibody as a homosandwich. In a non-enriched format, detection of E. coli was possible with a sensitivity of 2500 CFU/100 ml. Ultrasensitive detection of ~1 CFU/100 ml sample could be achieved by a prior pathogen enrichment step before the addition of the labeled antibody. The design of this diagnostic test is based on the common architecture of all bacteria, viruses and spores, namely the manifestation of repeat lipopolysaccharide epitopes on the surface. We have developed an easy-to-use two dot visual filter assay for translation into current water testing in public health laboratories to detect E. coli O157:H7. In a 5 h assay approximately 1 CFU and approximately 5 CFU of E. coli O157 could be detected in 100 ml of water or juice and lake samples respectively. This simple homosandwich enrichment strategy can also be used to detect low levels of other water-borne pathogens.

  4. Analysis of pharmaceutical and other organic wastewater compounds in filtered and unfiltered water samples by gas chromatography/mass spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Phillips, Patrick J.; Smith, Steven G.

    2014-01-01

    Research on the effects of exposure of stream biota to complex mixtures of pharmaceuticals and other organic compounds associated with wastewater requires the development of additional analytical capabilities for these compounds in water samples. Two gas chromatography/mass spectrometry (GC/MS) analytical methods used at the U.S. Geological Survey National Water Quality Laboratory (NWQL) to analyze organic compounds associated with wastewater were adapted to include additional pharmaceutical and other organic compounds beginning in 2009. This report includes a description of method performance for 42 additional compounds for the filtered-water method (hereafter referred to as the filtered method) and 46 additional compounds for the unfiltered-water method (hereafter referred to as the unfiltered method). The method performance for the filtered method described in this report has been published for seven of these compounds; however, the addition of several other compounds to the filtered method and the addition of the compounds to the unfiltered method resulted in the need to document method performance for both of the modified methods. Most of these added compounds are pharmaceuticals or pharmaceutical degradates, although two nonpharmaceutical compounds are included in each method. The main pharmaceutical compound classes added to the two modified methods include muscle relaxants, opiates, analgesics, and sedatives. These types of compounds were added to the original filtered and unfiltered methods largely in response to the tentative identification of a wide range of pharmaceutical and other organic compounds in samples collected from wastewater-treatment plants. Filtered water samples are extracted by vacuum through disposable solid-phase cartridges that contain modified polystyrene-divinylbenzene resin. Unfiltered samples are extracted by using continuous liquid-liquid extraction with dichloromethane. The compounds of interest for filtered and unfiltered sample

  5. Recommendations for Evaluating Multiple Filters in Ballast Water Management Systems for US Type Approval

    Science.gov (United States)

    2016-01-01

    8 Figure 5. Slotted tube ...ISO 1990). Slotted element refers to a filter where slots are created in a tubular shape (Figure 5). Figure 5. Slotted tube (HYDAC 2014...Hospital inpatient care General surgery Bag Filters - Non supported (flexible) microfine fiberglass or synthetic media, 12 to 36 inches deep

  6. Modeling water and sediment trapping by vegetated filters using vfsmod: comparing methods for estimating infiltration parameters

    Science.gov (United States)

    Amanda L. Fox; Dean E. Eisenhauer; Michael G. Dosskey

    2005-01-01

    Vegetated filters (buffers) are used to intercept overland runoff and reduce sediment and other contaminant loads to streams (Dosskey, 2001). Filters function by reducing runoff velocity and volume, thus enhancing sedimentation and infiltration. lnfiltration is the main mechanism for soluble contaminant removal, but it also plays a role in suspended particle removal....

  7. Optimizing nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Smets, Barth F.; Lee, Carson Odell

    Addition of phosphate or trace metals or better management e.g. in terms of anmonium load can improve the nitrification rate and efficiency in biological rapid sand filters.......Addition of phosphate or trace metals or better management e.g. in terms of anmonium load can improve the nitrification rate and efficiency in biological rapid sand filters....

  8. Working to reverse a water deficit | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... and Yugoslavia, Bataineh began work for the Ministry of Water and Irrigation in 1975. ... cubic metres of wastewater treated in Jordan can only be used in agriculture ... Consequently, the ministry has started to improve existing wastewater ...

  9. Quantification of trace metals in water using complexation and filter concentration.

    Science.gov (United States)

    Dolgin, Bella; Bulatov, Valery; Japarov, Julia; Elish, Eyal; Edri, Elad; Schechter, Israel

    2010-06-15

    Various metals undergo complexation with organic reagents, resulting in colored products. In practice, their molar absorptivities allow for quantification in the ppm range. However, a proper pre-concentration of the colored complex on paper filter lowers the quantification limit to the low ppb range. In this study, several pre-concentration techniques have been examined and compared: filtering the already complexed mixture, complexation on filter, and dipping of dye-covered filter in solution. The best quantification has been based on the ratio of filter reflectance at a certain wavelength to that at zero metal concentration. The studied complex formations (Ni ions with TAN and Cd ions with PAN) involve production of nanoparticle suspensions, which are associated with complicated kinetics. The kinetics of the complexation of Ni ions with TAN has been investigated and optimum timing could be found. Kinetic optimization in regard to some interferences has also been suggested.

  10. Water Conservation and Reuse. Instructor Guide. Working for Clean Water: An Information Program for Advisory Committees.

    Science.gov (United States)

    Pennsylvania State Univ., Middletown. Inst. of State and Regional Affairs.

    Described is a learning session on water conservation intended for citizen advisory groups interested in water quality planning. Topics addressed in this instructor's manual include water conservation needs, benefits, programs, technology, and problems. These materials are components of the Working for Clean Water Project. (Author/WB)

  11. Radium desorption, manganese and iron dissolution from sand filters of a conventional ground water treatment plant under reductive conditions

    International Nuclear Information System (INIS)

    Al-Hobaib, A.S.; Al-Sulaiman, K.M.; Al-Dhayan, D.M.; Al-Suhybani, A.A.

    2006-01-01

    Sand filters are used as a filter bed in many ground water treatment plants to remove the physical contaminants and oxidation products. A build-up of radioactivity may take place on the granules, where iron and manganese oxides are deposited and form thin films on the surface of sand filter. The oxides of iron and manganese play an important role in adsorbing radium from ground water. The disposal of those granules makes a significant problem. A batch technique is used for solubilization of radium from sand filters in the presence of some organic acids, which act as reducing agents. These acids are formic acid, acetic acid, benzoic acid, succinic acid, oxalic acid, phthalic acid, and adipic acid. The data were obtained as a function of acidity, temperature, contact time and liquid/solid ratio particle size and shaking speed. It was found that oxalic acid was the best for radium removal. The effectiveness of these acids on radium removal was as follows: oxalic acid > phthalic acid > adipic acid > succinic acid > formic acid > acetic acid. The maximum removal obtained was 69.9% at 1M oxalic acid at 8 ml/g ratio. Reaction kinetics and mechanism parameters of the dissolution process were studied and compared with other published data. (author)

  12. Hygienic safety of reusable tap water filters (Germlyser® with an operating time of 4 or 8 weeks in a haematological oncology transplantation unit

    Directory of Open Access Journals (Sweden)

    Rochow Markus

    2007-05-01

    Full Text Available Abstract Background Microbial safe tap water is crucial for the safety of immunosuppressed patients. Methods To evaluate the suitability of new, reusable point-of-use filters (Germlyser®, Aquafree GmbH, Hamburg, Germany, three variations of a reusable filter with the same filter principle but with different outlets (with and without silver and inner surface coating of the filter encasements (with and without nano-crystalline silver were tested. The filter efficacy was monitored over 1, 4 and 8 weeks operating time in a haematological oncology transplantation unit equipped with 18 water outlets (12 taps, 6 showers. Results The filtered water fulfilled the requirements of absence of pathogens over time. From 348 samples, 8 samples (2.3% exceeded 100 cfu/ml (no sample ≥ 500 cfu/ml. As no reprocessed filter exhibited 100% filter efficacy in the final quality control after each reprocessing, these contaminations could be explained by retrograde contamination during use. Conclusion As a consequence of the study, the manufacturer recommends changing filters after 4 weeks in high risk areas and after 8 weeks in moderate infectious risk areas, together with routine weekly alcohol-based surface disinfection and additionally in case of visible contamination. The filter efficacy of the 3 filters types did not differ significantly regarding total bacterial counts. Manual reprocessing proved to be insufficient. Using a validated reprocessing in a washer/disinfector with alkaline, acid treatment and thermic disinfection, the filters were effectively reprocessable and now provide tap water meeting the German drinking water regulations as well as the WHO guidelines, including absence of pathogens.

  13. Comparison of k Q factors measured with a water calorimeter in flattening filter free (FFF) and conventional flattening filter (cFF) photon beams

    Science.gov (United States)

    de Prez, Leon; de Pooter, Jacco; Jansen, Bartel; Perik, Thijs; Wittkämper, Frits

    2018-02-01

    Recently flattening filter free (FFF) beams became available for application in modern radiotherapy. There are several advantages of FFF beams over conventional flattening filtered (cFF) beams, however differences in beam spectra at the point of interest in a phantom potentially affect the ion chamber response. Beams are also non-uniform over the length of a typical reference ion chamber and recombination is usually larger. Despite several studies describing FFF beam characteristics, only a limited number of studies investigated their effect on k Q factors. Some of those studies predicted significant discrepancies in k Q factors (0.4% up to 1.0%) if TPR20,10 based codes of practice (CoPs) were to be used. This study addresses the question to which extent k Q factors, based on a TPR20,10 CoP, can be applied in clinical reference dosimetry. It is the first study that compares k Q factors measured directly with an absorbed dose to water primary standard in FFF-cFF pairs of clinical photon beams. This was done with a transportable water calorimeter described elsewhere. The measurements corrected for recombination and beam radial non-uniformity were performed in FFF-cFF beam pairs at 6 MV and 10 MV of an Elekta Versa HD for a selection of three different Farmer-type ion chambers (eight serial numbers). The ratio of measured k Q factors of the FFF-cFF beam pairs were compared with the TPR20,10 CoPs of the NCS and IAEA and the %dd(10) x CoP of the AAPM. For the TPR20,10 based CoPs differences less than 0.23% were found in k Q factors between the corresponding FFF-cFF beams with standard uncertainties smaller than 0.35%, while for the %dd(10) x these differences were smaller than 0.46% and within the expanded uncertainty of the measurements. Based on the measurements made with the equipment described in this study the authors conclude that the k Q factors provided by the NCS-18 and IAEA TRS-398 codes of practice can be applied for flattening filter free beams without

  14. Pollution patterns and underlying relationships of benzophenone-type UV-filters in wastewater treatment plants and their receiving surface water.

    Science.gov (United States)

    Wu, Ming-Hong; Li, Jian; Xu, Gang; Ma, Luo-Dan; Li, Jia-Jun; Li, Jin-Song; Tang, Liang

    2018-05-15

    The environmental behaviors of emerging pollutants, benzophenone-type UV filters (BP-UV filters) and their derivatives were investigated in four wastewater treatment plants (WWTPs), and their receiving surface waters in Shanghai. The concentration level of selected BP-UV filters in the WWTPs was detected from ngL -1 to μgL -1 . BP (621-951ngL -1 ) and BP-3 (841-1.32 × 10 3 ngL -1 ) were the most abundant and highest detection frequency individuals among the target BP-UV filters in influents, whereas BP (198-400ngL -1 ), BP-4 (93.3-288ngL -1 ) and BP-3 (146-258ngL -1 ) were predominant in effluents. BP-UV filters cannot be completely removed and the total removal efficiency varied widely (-456% to 100%) during the treatment process. It can be inferred that the usage of BP and BP-3 are higher than other BP-UV filters in the study area. The lowest and highest levels were BP-2 (ND-7.66ngL -1 ) and BP-3 (68.5-5.01 × 10 3 ng L -1 ) in the receiving surface water, respectively. Interestingly, the seasonal variation of BP-3 is larger than those of other BP-UV filters in surface water from Shanghai. There is no obvious pollution pattern of BP-UV filters in the surface water from the cosmetic factory area. The correlation analysis of BP-UV filters between WWTPs effluents and nearby downstream water samples suggested that BP-UV filters emitted from some WWTPs might be the main source of receiving surface water. Preliminary risk assessment indicated that the levels of BP-UV filters detected by the effluent posed medium to high risk to fish as well as other aquatic organisms. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Arsenic in drinking water wells on the Bolivian high plain: field monitoring and effect of salinity on removal efficiency of iron-oxides-containing filters

    OpenAIRE

    Van den Bergh, Kenneth; Du Laing, Gijs; Montoya, Juan; De Deckere, E; Tack, Filip

    2010-01-01

    In the rural areas around Oruro (Bolivia), untreated groundwater is used directly as drinking water. This research aimed to evaluate the general drinking water quality, with focus on arsenic (As) concentrations, based on analysis of 67 samples from about 16 communities of the Oruro district. Subsequently a filter using Iron Oxide Coated Sand (IOCS) and a filter using a Composite Iron Matrix (CIM) were tested for their arsenic removal capacity using synthetic water mimicking real groundwater. ...

  16. Social benefits in the Working for Water programme as a public works initiative

    CSIR Research Space (South Africa)

    Magadlela, D

    2004-01-01

    Full Text Available The Working for Water programme is a pioneering environmental conservation initiative in that its implementation successfully combines ecological concerns and social development benefits. By addressing unemployment, skills training and empowerment...

  17. The occurrence of UV filters in natural and drinking water in São Paulo State (Brazil).

    Science.gov (United States)

    da Silva, Claudia Pereira; Emídio, Elissandro Soares; de Marchi, Mary Rosa Rodrigues

    2015-12-01

    Ultraviolet (UV) filters are widely used in the formulation of personal care products (PCPs) to prevent damage to the skin, lips, and hair caused by excessive UV radiation. Therefore, large amounts of these substances are released daily into the aquatic environment through either recreational activities or the release of domestic sewage. The concern regarding the presence of such substances in the environment and the exposure of aquatic organisms is based on their potential for bioaccumulation and their potential as endocrine disruptors. Although there are several reports regarding the occurrence and fate of UV filters in the aquatic environment, these compounds are still overlooked in tropical areas. In this study, we investigated the occurrence of the organic UV filters benzophenone-3 (BP-3), ethylhexyl salicylate (ES), ethylhexyl methoxycinnamate (EHMC), and octocrylene (OC) in six water treatment plants in various cities in Southeast Brazil over a period of 6 months to 1 year. All of the UV filters studied were detected at some time during the sampling period; however, only EHMC and BP-3 were found in quantifiable concentrations, ranging from 55 to 101 and 18 to 115 ng L(-1), respectively. Seasonal variation of BP-3 was most clearly noticed in the water treatment plant in Araraquara, São Paulo, where sampling was performed for 12 months. BP-3 was not quantifiable in winter but was quantifiable in summer. The levels of BP-3 were in the same range in raw, treated and chlorinated water, indicating that the compound was not removed by the water treatment process.

  18. Automation of the electromagnetic filter applied for condensation water treatment in the secondary cooling system of the Paks Nuclear Power Plant

    International Nuclear Information System (INIS)

    Szilagyi, Gyoergy

    1989-01-01

    A full-flow condensation water purification system is applied in the secondary cooling circuit of the Paks NPP. The electromagnetic filter of the filtering system eliminates ferromagnetic impurities. The filter consists of a high current coil and an automatic control unit. During the improvement of this unit, a FESTO FPC-404 type controller based on an extended capability PLC was installed. (R.P.) 5 figs

  19. Iron turbidity removal from the active process water system of the Kaiga Generating Station Unit 1 using an electrochemical filter

    International Nuclear Information System (INIS)

    Venkateswaran, G.; Gokhale, B.K.

    2007-01-01

    Iron turbidity is observed in the intermediate cooling circuit of the active process water system (APWS) of Kaiga Generating Station (KGS). Deposition of hydrous/hydrated oxides of iron on the plate type heat exchanger, which is employed to transfer heat from the APWS to the active process cooling water system (APCWS), can in turn result in higher moderator D 2 O temperatures due to reduced heat transfer. Characterization of turbidity showed that the major component is γ-FeOOH. An in-house designed and fabricated electrochemical filter (ECF) containing an alternate array of 33 pairs of cathode and anode graphite felts was successfully tested for the removal of iron turbidity from the APWS of Kaiga Generating Station Unit No. 1 (KGS No. 1). A total volume of 52.5 m 3 water was processed using the filter. At an average inlet turbidity of 5.6 nephelometric turbidity units (NTU), the outlet turbidity observed from the ECF was 1.6 NTU. A maximum flow rate (10 L . min -1 ) and applied potential of 18.0-20.0 V was found to yield an average turbidity-removal efficiency of ∝ 75 %. When the experiment was terminated, a throughput of > 2.08 . 10 5 NTU-liters was realized without any reduction in the removal efficiency. Removal of the internals of the filter showed that only the bottom 11 pairs of felts had brownish deposits, while the remaining felts looked clean and unused. (orig.)

  20. The Effects of Two Types of Sleep Deprivation on Visual Working Memory Capacity and Filtering Efficiency

    OpenAIRE

    Drummond, Sean P. A.; Anderson, Dane E.; Straus, Laura D.; Vogel, Edward K.; Perez, Veronica B.

    2012-01-01

    Sleep deprivation has adverse consequences for a variety of cognitive functions. The exact effects of sleep deprivation, though, are dependent upon the cognitive process examined. Within working memory, for example, some component processes are more vulnerable to sleep deprivation than others. Additionally, the differential impacts on cognition of different types of sleep deprivation have not been well studied. The aim of this study was to examine the effects of one night of total sleep depri...

  1. A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates

    Science.gov (United States)

    Maurice, P.A.; Pullin, M.J.; Cabaniss, S.E.; Zhou, Q.; Namjesnik-Dejanovic, K.; Aiken, G.R.

    2002-01-01

    This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (??), absorbance at 280nm normalized to moles C (??280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO>XAD-8>RFW>XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO

  2. Reuse of filter backwash water with a submerged microfiltration membrane system; Wiederverwendung von Filterspuelwaessern durch Mikrofiltration mit getauchten Membranen

    Energy Technology Data Exchange (ETDEWEB)

    Koetzle, T.; Merkl, G.; Wilderer, P. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl und Lab. fuer Wasserguete- und Abfallwirtschaft; Backhaus, J. [Erlanger Stadtwerke AG, Erlangen (Germany); Hagen, K. [VA TECH WABAG GmbH Kulmbach, Kulmbach (Germany)

    2000-12-01

    During the treatment of groundwater by filtration for drinking water purposes, approximately 3% of the treated water volume has to be used as filter backwash water. Until now this backwash water charged with the accumulated filtrate is then redirected into sewers or receiving waters, either directly or after a sedimentation step. With sufficient separation of the filtered substances from backwash water this could again be used for drinking water purposes. This conserves natural groundwater resources and significantly reduces the volume of wastewater discharged. Especially in the face of the increasing shortage of useable groundwater resources in many countries, this will become increasingly important in the future. In our project, supported by 'EU-Life', the Technical University of Munich will examine on a large-scale plant according to the WABAG-SMS-Process, how far cross-flow microfiltration is capable of purifying the backwash waters for drinking water purposes again. The pilot-plant consists of two treatment parts, one charged with backwash water from the iron-, manganese- and arsenic-elimination, the other charged with backwash water from the deacidification. The membrane modules are submerged in closed storage basins for backwash water. Air is supplied under the modules to generate a defined cross-flow. This article discusses the results after one year of operation of the plant. (orig.) [German] Bei der Aufbereitung von Grundwasser durch Filtration in der Trinkwasseraufbereitung muessen etwa 3% der aufbereiteten Wassermenge zur Rueckspuelung der Filter verwendet werden. Bisher werden die hierbei anfallenden und mit den zuvor abfiltrierten Stoffen belasteten Filterspuelwaesser je nach den oertlichen Gegebenheiten unmittelbar oder nach einer Sedimentationsstufe in Vorfluter oder die oeffentliche Sammelkanalisation abgeschlagen. Durch eine hinreichende Trennung der abfiltrierten Stoffe vom Filterspuelwasser koennte dieses wieder der

  3. Occurrence, distribution and ecological risk assessment of multiple classes of UV filters in surface waters from different countries.

    Science.gov (United States)

    Tsui, Mirabelle M P; Leung, H W; Wai, Tak-Cheung; Yamashita, Nobuyoshi; Taniyasu, Sachi; Liu, Wenhua; Lam, Paul K S; Murphy, Margaret B

    2014-12-15

    Organic UV filters are common ingredients of personal care products (PCPs), but little is known about their distribution in and potential impacts to the marine environment. This study reports the occurrence and risk assessment of twelve widely used organic UV filters in surface water collected in eight cities in four countries (China, the United States, Japan, and Thailand) and the North American Arctic. The number of compounds detected, Hong Kong (12), Tokyo (9), Bangkok (9), New York (8), Los Angeles (8), Arctic (6), Shantou (5) and Chaozhou (5), generally increased with population density. Median concentrations of all detectable UV filters were ethylhexyl methoxycinnamate (EHMC) were more likely to pose a risk to fishes and also posed high risk of bleaching in hard corals in aquatic recreational areas in Hong Kong. This study is the first to report the occurrence of organic UV filters in the Arctic and provides a wider assessment of their potential negative impacts in the marine environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Manganese dioxide-coated filters for removing radium from drinking water. Report for 19 September 1983-1 September 1987

    International Nuclear Information System (INIS)

    Menetrez, M.Y.; Anderson, D.G.; Stahel, E.P.

    1988-09-01

    Research was performed using manganese dioxide (MnO 2 ) to demonstrate that above pH3 cations are adsorbed from solution in the order of their affinity, and that the interaction is characterized by the pH dependence of the metal. The relationship of the zero-point charge of pH and the solution ionic strength effects on interfacial surface potential and adsorption were addressed. Characteristics of MnO 2 behavior, structure, and stability found in research investigation were reviewed. Most of the study was on the use of MnO 2 coated filters for the removal of radium. A few comparison tests on radium removal with ion exchange were also made. Specifically, these tests have shown that acrylic-fiber filters coated with MnO 2 will remove radium from water. For a high-hardness water with pH = 7.4, total radium removal was 14,200 pCi/g MnO 2 before the MCL of 5 pCi/L was exceeded, and for a low-hardness water with pH = 4.5, total radium removal was 5000 pCi/g MnO 2 before the MCL of 5 pCi/L was exceeded. Hardness passed through the MnO 2 filters with little change and, therefore, radium was highly preferred over hardness. A step-by-step process for the preparation of acrylic-fiber filters coated with MnO 2 was designed and operated successfully

  5. Effects of closed immersion filtered water flow velocity on the ablation threshold of bisphenol A polycarbonate during excimer laser machining

    International Nuclear Information System (INIS)

    Dowding, Colin; Lawrence, Jonathan

    2010-01-01

    A closed flowing thick film filtered water immersion technique ensures a controlled geometry for both the optical interfaces of the flowing liquid film and allows repeatable control of flow-rate during machining. This has the action of preventing splashing, ensures repeatable machining conditions and allows control of liquid flow velocity. To investigate the impact of this technique on ablation threshold, bisphenol A polycarbonate samples have been machined using KrF excimer laser radiation passing through a medium of filtered water flowing at a number of flow velocities, that are controllable by modifying the liquid flow-rates. An average decrease in ablation threshold of 7.5% when using turbulent flow velocity regime closed thick film filtered water immersed ablation, compared to ablation using a similar beam in ambient air; however, the use of laminar flow velocities resulted in negligible differences between closed flowing thick film filtered water immersion and ambient air. Plotting the recorded threshold fluence achieved with varying flow velocity showed that an optimum flow velocity of 3.00 m/s existed which yielded a minimum ablation threshold of 112 mJ/cm 2 . This is attributed to the distortion of the ablation plume effected by the flowing immersion fluid changing the ablation mechanism: at laminar flow velocities Bremsstrahlung attenuation decreases etch rate, at excessive flow velocities the plume is completely destroyed, removing the effect of plume etching. Laminar flow velocity regime ablation is limited by slow removal of debris causing a non-linear etch rate over 'n' pulses which is a result of debris produced by one pulse remaining suspended over the feature for the next pulse. The impact of closed thick film filtered water immersed ablation is dependant upon beam fluence: high fluence beams achieved greater etch efficiency at high flow velocities as the effect of Bremsstrahlung attenuation is removed by the action of the fluid on the plume; low

  6. Assessment of ground-water flow and chemical transport in a tidally influenced aquifer using geostatistical filtering and hydrocarbon fingerprinting

    International Nuclear Information System (INIS)

    Marquis, S.A. Jr.; Smith, E.A.

    1994-01-01

    Traditional environmental investigations at tidally influenced hazardous waste sites such as marine fuel storage terminals have generally failed to characterize ground-water flow and chemical transport because they have been based on only a cursory knowledge of plume geometry, chemicals encountered, and hydrogeologic setting and synoptic ground-water level measurement. Single-time observations cannot be used to accurately determine flow direction and gradient in tidally fluctuating aquifers since these measurements delineate hydraulic head at only one point in time during a tidal cycle, not the net effect of the fluctuations. In this study, a more rigorous approach was used to characterize flow and chemical transport in a tidally influenced aquifer at a marine fuel storage terminal using: (1) ground-water-level monitoring over three tidal cycles (72 hours), (2) geostatistical filtering of ground-water-level data using 25-hour and 71-hour filtering methods, and (3) hydrocarbon fingerprinting analysis. The results from the study indicate that naphtha released from one of the on-site naphtha tanks has been the predominant contributor to the hydrocarbon plume both on-site and downgradient off-site and that net ground-water and hydrocarbon movement has been to the southeast away from the tank since 1989

  7. Optimization of filter loading

    International Nuclear Information System (INIS)

    Turney, J.H.; Gardiner, D.E.; Sacramento Municipal Utility District, Herald, CA)

    1985-01-01

    The introduction of 10 CFR Part 61 has created potential difficulties in the disposal of spent cartridge filters. When this report was prepared, Rancho Seco had no method of packaging and disposing of class B or C filters. This work examined methods to minimize the total operating cost of cartridge filters while maintaining them below the class A limit. It was found that by encapsulating filters in cement the filter operating costs could be minimized

  8. Designing Programme Implementation Strategies to Increase the Adoption and Use of Biosand Water Filters in Rural India

    Directory of Open Access Journals (Sweden)

    Tommy K.K. Ngai

    2014-06-01

    Full Text Available Low-cost household water treatment systems are innovations designed to improve the quality of drinking water at the point of use. This study investigates how an NGO can design appropriate programme strategies in order to increase the adoption and sustained use of household sand filters in rural India. A system dynamics computer model was developed and used to assess 18 potential programme strategies for their effectiveness in increasing filter use at two and ten years into the future, under seven scenarios of how the external context may plausibly evolve. The results showed that the optimal choice of strategy is influenced by the macroeconomic situation, donor funding, presence of alternative options, and the evaluation time frame. The analysis also revealed some key programme management challenges, including the trade-off between optimising short- or long-term gains, and counter-intuitive results, such as higher subsidy fund allocation leading to fewer filter distribution, and technology advances leading to fewer sales. This study outlines how an NGO can choose effective strategies in consideration of complex system interactions. This study demonstrated that small NGOs can dramatically increase their programme outcomes without necessarily increasing operational budget.

  9. Behavioral Reactivity Associated With Electronic Monitoring of Environmental Health Interventions--A Cluster Randomized Trial with Water Filters and Cookstoves.

    Science.gov (United States)

    Thomas, Evan A; Tellez-Sanchez, Sarita; Wick, Carson; Kirby, Miles; Zambrano, Laura; Abadie Rosa, Ghislaine; Clasen, Thomas F; Nagel, Corey

    2016-04-05

    Subject reactivity--when research participants change their behavior in response to being observed--has been documented showing the effect of human observers. Electronics sensors are increasingly used to monitor environmental health interventions, but the effect of sensors on behavior has not been assessed. We conducted a cluster randomized controlled trial in Rwanda among 170 households (70 blinded to the presence of the sensor, 100 open) testing whether awareness of an electronic monitor would result in a difference in weekly use of household water filters and improved cookstoves over a four-week surveillance period. A 63% increase in number of uses of the water filter per week between the groups was observed in week 1, an average of 4.4 times in the open group and 2.83 times in the blind group, declining in week 4 to an insignificant 55% difference of 2.82 uses in the open, and 1.93 in the blind. There were no significant differences in the number of stove uses per week between the two groups. For both filters and stoves, use decreased in both groups over four-week installation periods. This study suggests behavioral monitoring should attempt to account for reactivity to awareness of electronic monitors that persists for weeks or more.

  10. Peatlands as Filters for Polluted Mine Water?—A Case Study from an Uranium-Contaminated Karst System in South Africa—Part III: Quantifying the Hydraulic Filter Component

    Directory of Open Access Journals (Sweden)

    Frank Winde

    2011-03-01

    Full Text Available As Part III of a four-part series on the filter function of peat for uranium (U, this paper focuses on the hydraulic component of a conceptual filter model introduced in Part II. This includes the quantification of water flow through the wetland as a whole, which was largely unknown and found to be significantly higher that anticipated. Apart from subaquatic artesian springs associated with the underlying karst aquifer the higher flow volumes were also caused by plumes of polluted groundwater moving laterally into the wetland. Real-time, quasi-continuous in situ measurements of porewater in peat and non-peat sediments indicate that rising stream levels (e.g., during flood conditions lead to the infiltration of stream water into adjacent peat deposits and thus allow for a certain proportion of flood water to be filtered. However, changes in porewater quality triggered by spring rains may promote the remobilization of possibly sorbed U.

  11. Biodegradation behavior of natural organic matter (NOM) in a biological aerated filter (BAF) as a pretreatment for ultrafiltration (UF) of river water

    KAUST Repository

    Huang, Guocheng; Meng, Fangang; Zheng, Xing; Wang, Yuan; Wang, Zhigang; Liu, Huijun; Jekel, Martin R.

    2011-01-01

    In this study, biodegradation of natural organic matter (NOM) in a biological aerated filter (BAF) as pretreatment of UF treating river water was investigated. Photometric measurement, three-dimensional excitation-emission matrix (EEM) fluorescence

  12. Modification of cellulose foam paper for use as a high-quality biocide disinfectant filter for drinking water.

    Science.gov (United States)

    Heydarifard, Solmaz; Taneja, Kapila; Bhanjana, Gaurav; Dilbaghi, Neeraj; Nazhad, Mousa M; Kim, Ki-Hyun; Kumar, Sandeep

    2018-02-01

    Development of a foam-formed cellulose filter paper with high wet strength was carried out for application as a drinking water filter. The wet strength and antimicrobial activity of cellulose foam paper against several bacteria species (Bacillus subtilis MTCC 441 (Gram +ve), B. cereus NCDC 240 (Gram +ve), Pseudomonas aeruginosa NCDC 105 (Gram -ve), Klebsiella pneumonia NCDC 138 (Gram -ve), and Escherichia coli MTCC 40 (Gram -ve)) were investigated. The morphology and structure of the cellulose foam paper were characterized using scanning electron microscopy (SEM). The results of our study confirmed that glutaraldehyde solution or 1,2,3,4-butanetetracarboxylic acid (BTCA) added to cellulose foam paper pretreated with cationic polyacrylamide (C-PAM) provided very high and stable wet strength performance together with excellent antimicrobial properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Organising Water: The Hidden Role of Intermediary Work

    Directory of Open Access Journals (Sweden)

    Timothy Moss

    2009-02-01

    Full Text Available The increasingly complex challenges of making water management more sustainable require a critical and detailed understanding of the social organisation of water. This paper examines the hitherto neglected role that 'intermediary' organisations play in reshaping the relations between the provision and use of water and sanitation services. In response to new regulatory, environmental, social, and commercial pressures the relationships between water utilities, consumers, and regulators are changing, creating openings for both new and existing organisations to take on intermediary functions. Drawing on recent EU-funded research we provide the first systematic analysis of intermediary organisations in the European water sector, examining the contexts of their emergence, the ways they work, the functions they perform, and the impacts they can have. With a combination of conceptual and empirical analysis we substantiate and elaborate the case for appreciating the often hidden work of intermediaries. We caution, however, against over-simplistic conclusions on harnessing this potential, highlighting instead the need to reframe perspectives on how water is organised to contemplate actor constellations and interactions beyond the common triad of provider, consumer, and regulator.

  14. Estimation of water level and steam temperature using ensemble Kalman filter square root (EnKF-SR)

    Science.gov (United States)

    Herlambang, T.; Mufarrikoh, Z.; Karya, D. F.; Rahmalia, D.

    2018-04-01

    The equipment unit which has the most vital role in the steam-powered electric power plant is boiler. Steam drum boiler is a tank functioning to separate fluida into has phase and liquid phase. The existence in boiler system has a vital role. The controlled variables in the steam drum boiler are water level and the steam temperature. If the water level is higher than the determined level, then the gas phase resulted will contain steam endangering the following process and making the resulted steam going to turbine get less, and the by causing damages to pipes in the boiler. On the contrary, if less than the height of determined water level, the resulted height will result in dry steam likely to endanger steam drum. Thus an error was observed between the determined. This paper studied the implementation of the Ensemble Kalman Filter Square Root (EnKF-SR) method in nonlinear model of the steam drum boiler equation. The computation to estimate the height of water level and the temperature of steam was by simulation using Matlab software. Thus an error was observed between the determined water level and the steam temperature, and that of estimated water level and steam temperature. The result of simulation by Ensemble Kalman Filter Square Root (EnKF-SR) on the nonlinear model of steam drum boiler showed that the error was less than 2%. The implementation of EnKF-SR on the steam drum boiler r model comprises of three simulations, each of which generates 200, 300 and 400 ensembles. The best simulation exhibited the error between the real condition and the estimated result, by generating 400 ensemble. The simulation in water level in order of 0.00002145 m, whereas in the steam temperature was some 0.00002121 kelvin.

  15. COMPARISON OF MEMBRANE FILTER, MULTIPLE-FERMENTATION-TUBE, AND PRESENCE-ABSENCE TECHNIQUES FOR DETECTING TOTAL COLIFORMS IN SMALL COMMUNITY WATER SYSTEMS

    Science.gov (United States)

    Methods for detecting total coliform bacteria in drinking water were compared using 1483 different drinking water samples from 15 small community water systems in Vermont and New Hampshire. The methods included the membrane filter (MF) technique, a ten tube fermentation tube tech...

  16. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - PHYSICAL REMOVAL OF MICROBIOLOGICAL AND PARTICULATE CONTAMINANTS IN DRINKING WATER : SEPARMATIC™ FLUID SYSTEMS DIATOMACEOUS EARTH PRESSURE TYPE FILTER SYSTEM MODEL 12P-2

    Science.gov (United States)

    The verification test of the SeparmaticTM DE Pressure Type Filter System Model 12P-2 was conducted at the UNH Water Treatment Technology Assistance Center (WTTAC) in Durham, New Hampshire. The source water was finished water from the Arthur Rollins Treatment Plant that was pretr...

  17. Performance of ceramic disk filter coated with nano ZnO for removing Escherichia coli from water in small rural and remote communities of developing regions.

    Science.gov (United States)

    Huang, Jing; Huang, Guohe; An, Chunjiang; He, Yuan; Yao, Yao; Zhang, Peng; Shen, Jian

    2018-03-12

    Global water safety is facing great challenges due to increased population and demand. There is an urgent need to develop suitable water treatment strategy for small rural and remote communities in low-income developing countries. In order to find a low-cost solution, the reduction of E. coli using ceramic water disk coated with nano ZnO was investigated in this study. The performance of modified ceramic disk filters was influenced by several factors in the filter production process. Based on the factorial analysis, the pore size of the disk filters was the most significant factor for influencing E. coli removal efficiency and the clay content was the most significant one for influencing flow rate of modified disk filters. The coating of nano ZnO led to the change of disk filter surface and porosity. The reduction of E. coli could be attributed to both filter retention and photocatalytic antibacterial activity of nano ZnO. The effects of filter operation factors including initial E. coli concentration, illumination time and lamp power on E. coli removal effectiveness were also revealed. The results can help find a safe and cost-effective approach to solve drinking water problems in small rural and remote communities of developing regions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Process evaluation and assessment of use of a large scale water filter and cookstove program in Rwanda

    Directory of Open Access Journals (Sweden)

    Christina K. Barstow

    2016-07-01

    Full Text Available Abstract Background In an effort to reduce the disease burden in rural Rwanda, decrease poverty associated with expenditures for fuel, and minimize the environmental impact on forests and greenhouse gases from inefficient combustion of biomass, the Rwanda Ministry of Health (MOH partnered with DelAgua Health (DelAgua, a private social enterprise, to distribute and promote the use of improved cookstoves and advanced water filters to the poorest quarter of households (Ubudehe 1 and 2 nationally, beginning in Western Province under a program branded Tubeho Neza (“Live Well”. The project is privately financed and earns revenue from carbon credits under the United Nations Clean Development Mechanism. Methods During a 3-month period in late 2014, over 470,000 people living in over 101,000 households were provided free water filters and cookstoves. Following the distribution, community health workers visited nearly 98 % of households to perform household level education and training activities. Over 87 % of households were visited again within 6 months with a basic survey conducted. Detailed adoption surveys were conducted among a sample of households, 1000 in the first round, 187 in the second. Results Approximately a year after distribution, reported water filter use was above 90 % (+/−4 % CI and water present in filter was observed in over 76 % (+/−6 % CI of households, while the reported primary stove was nearly 90 % (+/−4.4 % CI and of households cooking at the time of the visit, over 83 % (+/−5.3 % CI were on the improved stove. There was no observed association between household size and stove stacking behavior. Conclusions This program suggests that free distribution is not a determinant of low adoption. It is plausible that continued engagement in households, enabled by Ministry of Health support and carbon financed revenue, contributed to high adoption rates. Overall, the program was able to demonstrate a privately

  19. Nanofiber Filters Eliminate Contaminants

    Science.gov (United States)

    2009-01-01

    With support from Phase I and II SBIR funding from Johnson Space Center, Argonide Corporation of Sanford, Florida tested and developed its proprietary nanofiber water filter media. Capable of removing more than 99.99 percent of dangerous particles like bacteria, viruses, and parasites, the media was incorporated into the company's commercial NanoCeram water filter, an inductee into the Space Foundation's Space Technology Hall of Fame. In addition to its drinking water filters, Argonide now produces large-scale nanofiber filters used as part of the reverse osmosis process for industrial water purification.

  20. Non-porous membrane-assisted liquid-liquid extraction of UV filter compounds from water samples.

    Science.gov (United States)

    Rodil, Rosario; Schrader, Steffi; Moeder, Monika

    2009-06-12

    A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes non-porous membrane-assisted liquid-liquid extraction (MALLE) and LC-atmospheric pressure photoionization (APPI)-MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made membrane bags were prepared from low-density polyethylene in order to accommodate 100 microL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L(-1) (OD-PABA) and 16 ng L(-1) (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L(-1) (BP-3) and 4381 ng L(-1) (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L(-1) (OC).

  1. Fe-Ti/Fe (II)-loading on ceramic filter materials for residual chlorine removal from drinking water.

    Science.gov (United States)

    Man, Kexin; Zhu, Qi; Guo, Zheng; Xing, Zipeng

    2018-06-01

    Ceramic filter material was prepared with silicon dioxide (SiO 2 ), which was recovered from red mud and then modified with Fe (II) and Fe-Ti bimetal oxide. Ceramic filter material can be used to reduce the content of residual chlorine from drinking water. The results showed that after a two-step leaching process with 3 M hydrochloric acid (HCl) and 90% sulfuric acid (H 2 SO 4 ), the recovery of SiO 2 exceeded 80%. Fe (II)/Fe-Ti bimetal oxide, with a high adsorption capacity of residual chlorine, was prepared using a 3:1 M ratio of Fe/Ti and a concentration of 0.4 mol/L Fe 2+ . According to the zeta-potential, scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, Fe (II) and Fe-Ti bimetal oxide altered the zeta potential and structural properties of the ceramic filter material. There was a synergistic interaction between Fe and Ti in which FeOTi bonds on the material surface and hydroxyl groups provided the active sites for adsorption. Through a redox reaction, Fe (II) transfers hypochlorite to chloride, and FeOTiCl bonds were formed after adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Characterization of the water filters cartridges from the iea-r1 reactor using the Monte Carlo method

    International Nuclear Information System (INIS)

    Costa, Priscila; Potiens Junior, Ademar J.

    2015-01-01

    Filter cartridges are part of the primary water treatment system of the IEA-R1 Research Reactor and, when saturated, they are replaced and become radioactive waste. The IEA-R1 is located at the Nuclear and Energy Research Institute (IPEN), in Sao Paulo, Brazil. The primary characterization is the main step of the radioactive waste management in which the physical, chemical and radiological properties are determined. It is a very important step because the information obtained in this moment enables the choice of the appropriate management process and the definition of final disposal options. In this paper, it is presented a non-destructive method for primary characterization, using the Monte Carlo method associated with the gamma spectrometry. Gamma spectrometry allows the identification of radionuclides and their activity values. The detection efficiency is an important parameter, which is related to the photon energy, detector geometry and the matrix of the sample to be analyzed. Due to the difficult to obtain a standard source with the same geometry of the filter cartridge, another technique is necessary to calibrate the detector. The technique described in this paper uses the Monte Carlo method for primary characterization of the IEA-R1 filter cartridges. (author)

  3. DEMONSTRATION BULLETIN: COLLOID POLISHING FILTER METHOD - FILTER FLOW TECHNOLOGY, INC.

    Science.gov (United States)

    The Filter Flow Technology, Inc. (FFT) Colloid Polishing Filter Method (CPFM) was tested as a transportable, trailer mounted, system that uses sorption and chemical complexing phenomena to remove heavy metals and nontritium radionuclides from water. Contaminated waters can be pro...

  4. Manganese oxidation and bacterial diversity on different filter media coatings during the start-up of drinking water biofilters

    DEFF Research Database (Denmark)

    Breda, I. L.; Ramsay, L.; Roslev, P.

    2017-01-01

    Manganese removal is a typical concern in drinking water production. Biofiltration may be used when treating groundwater sources but the onset of manganese removal in virgin biofilters can vary considerably. The aim of this study was to investigate the effect of different filter media on manganese...... by manganese oxide, while 48, 57 and 72 days were required by virgin quartz, calcium carbonate and polystyrene, respectively. The bacterial community was investigated using DAPI staining, quantitative polymerase chain reaction (qPCR), 16S rRNA gene pyrosequencing, and bacterial enrichments. Bacterial abundance...

  5. Online analysis of five organic ultraviolet filters in environmental water samples using magnetism-enhanced monolith-based in-tube solid phase microextraction coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Mei, Meng; Huang, Xiaojia

    2017-11-24

    Due to the endocrine disrupting properties, organic UV filters have been a great risk for humans and other organisms. Therefore, development of accurate and effective analytical methods is needed for the determination of UV filters in environmental waters. In this work, a fast, sensitive and environmentally friendly method combining magnetism-enhanced monolith-based in-tube solid phase microextraction with high-performance liquid chromatography with diode array detection (DAD) (ME-MB-IT/SPME-HPLC-DAD) for the online analysis of five organic UV filters in environmental water samples was developed. To extract UV filters effectively, an ionic liquid-based monolithic capillary column doped with magnetic nanoparticles was prepared by in-situ polymerization and used as extraction medium of online ME-MB-IT/SPME-HPLC-DAD system. Several extraction conditions including the intensity of magnetic field, sampling and desorption flow rate, volume of sample and desorption solvent, pH value and ionic strength of sample matrix were optimized thoroughly. Under the optimized conditions, the extraction efficiencies for five organic UV filters were in the range of 44.0-100%. The limits of detection (S/N=3) and limits of quantification (S/N=10) were 0.04-0.26μg/L and 0.12-0.87μg/L, respectively. The precisions indicated by relative standard deviations (RSDs) were less than 10% for both intra- and inter-day variabilities. Finally, the developed method was successfully applied to the determination of UV filters in three environmental water samples and satisfactory results were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. A two-step crushed lava rock filter unit for grey water treatment at household level in an urban slum.

    Science.gov (United States)

    Katukiza, A Y; Ronteltap, M; Niwagaba, C B; Kansiime, F; Lens, P N L

    2014-01-15

    Decentralised grey water treatment in urban slums using low-cost and robust technologies offers opportunities to minimise public health risks and to reduce environmental pollution caused by the highly polluted grey water i.e. with a COD and N concentration of 3000-6000 mg L(-1) and 30-40 mg L(-1), respectively. However, there has been very limited action research to reduce the pollution load from uncontrolled grey water discharge by households in urban slums. This study was therefore carried out to investigate the potential of a two-step filtration process to reduce the grey water pollution load in an urban slum using a crushed lava rock filter, to determine the main filter design and operation parameters and the effect of intermittent flow on the grey water effluent quality. A two-step crushed lava rock filter unit was designed and implemented for use by a household in the Bwaise III slum in Kampala city (Uganda). It was monitored at a varying hydraulic loading rate (HLR) of 0.5-1.1 m d(-1) as well as at a constant HLR of 0.39 m d(-1). The removal efficiencies of COD, TP and TKN were, respectively, 85.9%, 58% and 65.5% under a varying HLR and 90.5%, 59.5% and 69%, when operating at a constant HLR regime. In addition, the log removal of Escherichia coli, Salmonella spp. and total coliforms was, respectively, 3.8, 3.2 and 3.9 under the varying HLR and 3.9, 3.5 and 3.9 at a constant HLR. The results show that the use of a two-step filtration process as well as a lower constant HLR increased the pollutant removal efficiencies. Further research is needed to investigate the feasibility of adding a tertiary treatment step to increase the nutrients and microorganisms removal from grey water. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Power cycles with ammonia-water mixtures as working fluid

    Energy Technology Data Exchange (ETDEWEB)

    Thorin, Eva

    2000-05-01

    It is of great interest to improve the efficiency of power generating processes, i.e. to convert more of the energy in the heat source to power. This is favorable from an environmental point of view and can also be an economic advantage. To use an ammonia-water mixture instead of water as working fluid is a possible way to improve the efficiency of steam turbine processes. This thesis includes studies of power cycles with ammonia-water mixtures as working fluid utilizing different kinds of heat sources for power and heat generation. The thermophysical properties of the mixture are also studied. They play an important role in the calculations of the process performance and for the design of its components, such as heat exchangers. The studies concern thermodynamic simulations of processes in applications suitable for Swedish conditions. Available correlations for the thermophysical properties are compared and their influence on simulations and heat exchanger area predictions is investigated. Measurements of ammonia-water mixture viscosities using a vibrating wire viscometer are also described. The studies performed show that power cycles with ammonia-water mixtures as the working fluid are well suited for utilization of waste heat from industry and from gas engines. The ammonia-water power cycles can give up to 32 % more power in the industrial waste heat application and up to 54 % more power in the gas engine bottoming cycle application compared to a conventional Rankine steam cycle. However, ammonia-water power cycles in small direct-fired biomass-fueled cogeneration plants do not show better performance than a conventional Rankine steam cycle. When different correlations for the thermodynamic properties are used in simulations of a simple ammonia-water power cycle the difference in efficiency is not larger than 4 %, corresponding to about 1.3 percentage points. The differences in saturation properties between the correlations are, however, considerable at high

  8. Assessing the impact of water filters and improved cook stoves on drinking water quality and household air pollution: a randomised controlled trial in Rwanda.

    Directory of Open Access Journals (Sweden)

    Ghislaine Rosa

    Full Text Available Diarrhoea and respiratory infections remain the biggest killers of children under 5 years in developing countries. We conducted a 5-month household randomised controlled trial among 566 households in rural Rwanda to assess uptake, compliance and impact on environmental exposures of a combined intervention delivering high-performance water filters and improved stoves for free. Compliance was measured monthly by self-report and spot-check observations. Semi-continuous 24-h PM2.5 monitoring of the cooking area was conducted in a random subsample of 121 households to assess household air pollution, while samples of drinking water from all households were collected monthly to assess the levels of thermotolerant coliforms. Adoption was generally high, with most householders reporting the filters as their primary source of drinking water and the intervention stoves as their primary cooking stove. However, some householders continued to drink untreated water and most continued to cook on traditional stoves. The intervention was associated with a 97.5% reduction in mean faecal indicator bacteria (Williams means 0.5 vs. 20.2 TTC/100 mL, p<0.001 and a median reduction of 48% of 24-h PM2.5 concentrations in the cooking area (p = 0.005. Further studies to increase compliance should be undertaken to better inform large-scale interventions.Clinicaltrials.gov; NCT01882777; http://clinicaltrials.gov/ct2/results?term=NCT01882777&Search=Search.

  9. Assessing the impact of water filters and improved cook stoves on drinking water quality and household air pollution: a randomised controlled trial in Rwanda.

    Science.gov (United States)

    Rosa, Ghislaine; Majorin, Fiona; Boisson, Sophie; Barstow, Christina; Johnson, Michael; Kirby, Miles; Ngabo, Fidele; Thomas, Evan; Clasen, Thomas

    2014-01-01

    Diarrhoea and respiratory infections remain the biggest killers of children under 5 years in developing countries. We conducted a 5-month household randomised controlled trial among 566 households in rural Rwanda to assess uptake, compliance and impact on environmental exposures of a combined intervention delivering high-performance water filters and improved stoves for free. Compliance was measured monthly by self-report and spot-check observations. Semi-continuous 24-h PM2.5 monitoring of the cooking area was conducted in a random subsample of 121 households to assess household air pollution, while samples of drinking water from all households were collected monthly to assess the levels of thermotolerant coliforms. Adoption was generally high, with most householders reporting the filters as their primary source of drinking water and the intervention stoves as their primary cooking stove. However, some householders continued to drink untreated water and most continued to cook on traditional stoves. The intervention was associated with a 97.5% reduction in mean faecal indicator bacteria (Williams means 0.5 vs. 20.2 TTC/100 mL, pcooking area (p = 0.005). Further studies to increase compliance should be undertaken to better inform large-scale interventions. Clinicaltrials.gov; NCT01882777; http://clinicaltrials.gov/ct2/results?term=NCT01882777&Search=Search.

  10. Integrated metagenomic and physiochemical analyses to evaluate the potential role of microbes in the sand filter of a drinking water treatment system.

    Directory of Open Access Journals (Sweden)

    Yaohui Bai

    Full Text Available While sand filters are widely used to treat drinking water, the role of sand filter associated microorganisms in water purification has not been extensively studied. In the current investigation, we integrated molecular (based on metagenomic and physicochemical analyses to elucidate microbial community composition and function in a common sand filter used to treat groundwater for potable consumption. The results revealed that the biofilm developed rapidly within 2 days (reaching ≈ 10(11 prokaryotes per gram in the sand filter along with abiotic and biotic particulates accumulated in the interstitial spaces. Bacteria (up to 90% dominated the biofilm microbial community, with Alphaproteobacteria being the most common class. Thaumarchaeota was the sole phylum of Archaea, which might be involved in ammonia oxidation. Function annotation of metagenomic datasets revealed a number of aromatic degradation pathway genes, such as aromatic oxygenase and dehydrogenase genes, in the biofilm, suggesting a significant role for microbes in the breakdown of aromatic compounds in groundwater. Simultaneous nitrification and denitrification pathways were confirmed as the primary routes of nitrogen removal. Dissolved heavy metals in groundwater, e.g. Mn(2+ and As(3+, might be biologically oxidized to insoluble or easily adsorbed compounds and deposited in the sand filter. Our study demonstrated that the role of the microbial community in the sand filter treatment system are critical to effective water purification in drinking water.

  11. Integrated metagenomic and physiochemical analyses to evaluate the potential role of microbes in the sand filter of a drinking water treatment system.

    Science.gov (United States)

    Bai, Yaohui; Liu, Ruiping; Liang, Jinsong; Qu, Jiuhui

    2013-01-01

    While sand filters are widely used to treat drinking water, the role of sand filter associated microorganisms in water purification has not been extensively studied. In the current investigation, we integrated molecular (based on metagenomic) and physicochemical analyses to elucidate microbial community composition and function in a common sand filter used to treat groundwater for potable consumption. The results revealed that the biofilm developed rapidly within 2 days (reaching ≈ 10(11) prokaryotes per gram) in the sand filter along with abiotic and biotic particulates accumulated in the interstitial spaces. Bacteria (up to 90%) dominated the biofilm microbial community, with Alphaproteobacteria being the most common class. Thaumarchaeota was the sole phylum of Archaea, which might be involved in ammonia oxidation. Function annotation of metagenomic datasets revealed a number of aromatic degradation pathway genes, such as aromatic oxygenase and dehydrogenase genes, in the biofilm, suggesting a significant role for microbes in the breakdown of aromatic compounds in groundwater. Simultaneous nitrification and denitrification pathways were confirmed as the primary routes of nitrogen removal. Dissolved heavy metals in groundwater, e.g. Mn(2+) and As(3+), might be biologically oxidized to insoluble or easily adsorbed compounds and deposited in the sand filter. Our study demonstrated that the role of the microbial community in the sand filter treatment system are critical to effective water purification in drinking water.

  12. Numerical and experimental design of ultrasonic particle filters for water treatment

    NARCIS (Netherlands)

    Cappon, H.J.

    2014-01-01

    Due to limited water resources available in the world and the ever growing world population, there is an increasing need for water recycling, recovery and multi-sourcing strategies. One of the new physical process technologies being investigated for water purification and/or constituent

  13. Filtering high resolution hyperspectral imagery and analyzing it for quantification of water quality parameters and aquatic vegetation

    Science.gov (United States)

    Pande-Chhetri, Roshan

    High resolution hyperspectral imagery (airborne or ground-based) is gaining momentum as a useful analytical tool in various fields including agriculture and aquatic systems. These images are often contaminated with stripes and noise resulting in lower signal-to-noise ratio, especially in aquatic regions where signal is naturally low. This research investigates effective methods for filtering high spatial resolution hyperspectral imagery and use of the imagery in water quality parameter estimation and aquatic vegetation classification. The striping pattern of the hyperspectral imagery is non-parametric and difficult to filter. In this research, a de-striping algorithm based on wavelet analysis and adaptive Fourier domain normalization was examined. The result of this algorithm was found superior to other available algorithms and yielded highest Peak Signal to Noise Ratio improvement. The algorithm was implemented on individual image bands and on selected bands of the Maximum Noise Fraction (MNF) transformed images. The results showed that image filtering in the MNF domain was efficient and produced best results. The study investigated methods of analyzing hyperspectral imagery to estimate water quality parameters and to map aquatic vegetation in case-2 waters. Ground-based hyperspectral imagery was analyzed to determine chlorophyll-a (Chl-a) concentrations in aquaculture ponds. Two-band and three-band indices were implemented and the effect of using submerged reflectance targets was evaluated. Laboratory measured values were found to be in strong correlation with two-band and three-band spectral indices computed from the hyperspectral image. Coefficients of determination (R2) values were found to be 0.833 and 0.862 without submerged targets and stronger values of 0.975 and 0.982 were obtained using submerged targets. Airborne hyperspectral images were used to detect and classify aquatic vegetation in a black river estuarine system. Image normalization for water

  14. PERFORMANCE OF A SURFACE FLOW CONSTRUCTED WETLAND SYSTEM USED TO TREAT SECONDARY EFFLUENT AND FILTER BACKWASH WATER

    Directory of Open Access Journals (Sweden)

    Juan Antonio Vidales-Contreras

    2011-05-01

    The performance of a surface flow wetland system used to treat activated sludge effluent and filter backwash water from a tertiary treatment facility was evaluated. Samples were collected before and after vegetation removal from the system which consists of two densely vegetated settling basins (0.35 ha, an artificial stream, and a 3-ha surface flow wetland. Bulrush (Scripus spp. and cattail (Typha domingensis were the dominant plant species. The average inflow of chlorinated secondary effluent during the first two months of the actual study was 1.9  m3 min-1 while the inflow for backwash water treatment ranged from 0.21 to 0.42 m3 min-1. The system was able to reduce TSS and BOD5 to tertiary effluent standards; however, monitoring of chloride concentrations revealed that wetland evapotranspiration is probably enriching pollutant concentrations in the wetland outflow. Coliphage removal from the filter backwash was 97 and 35% during 1999 and 2000, respectively. However, when secondary effluent entered the system, coliphage removal averaged 65%. After vegetation removal, pH and coliphage density increased significantly (p

  15. An innovative bovine odorant binding protein-based filtering cartridge for the removal of triazine herbicides from water.

    Science.gov (United States)

    Bianchi, Federica; Basini, Giuseppina; Grolli, Stefano; Conti, Virna; Bianchi, Francesco; Grasselli, Francesca; Careri, Maria; Ramoni, Roberto

    2013-01-01

    Odorant binding protein (OBP) is a multi-functional scavenger for small hydrophobic molecules dissolved in the mucus lining the nasal epithelia of mammals, characterized by broad ligand binding specificity towards a large number of structurally unrelated natural and synthetic molecules of different chemical classes. Here, we demonstrate for the first time the application of OBP as the active element of an innovative filtering matrix for the removal of environmental pollutants such as triazine herbicides from water samples. The filtering device, obtained by coupling histidine-tagged bovine OBP to a nickel nitrilotriacetic acid (Ni-NTA) agarose resin, was characterized in terms of retention capacity for the herbicides atrazine, simazine, and propazine. Analysis of these herbicides at trace levels with solid-phase microextraction followed by gas chromatography-mass spectrometry using the selected ion monitoring mode proved the capabilities of the proposed device for the decontamination of surface and groundwater samples in the 0.2-2,300 μg/L concentration range, obtaining a reduction in the triazine content greater than 97 %, thus suggesting its possible use for the potabilization of water.

  16. Terrestrial water storage changes over Xinjiang extracted by combining Gaussian filter and multichannel singular spectrum analysis from GRACE

    Science.gov (United States)

    Guo, Jinyun; Li, Wudong; Chang, Xiaotao; Zhu, Guangbin; Liu, Xin; Guo, Bin

    2018-04-01

    Water resource management is crucial for the economic and social development of Xinjiang, an arid area located in the Northwest China. In this paper, the time variations of gravity recovery and climate experiment (GRACE)-derived monthly gravity field models from 2003 January to 2013 December are analysed to study the terrestrial water storage (TWS) changes in Xinjiang using the multichannel singular spectrum analysis (MSSA) with a Gaussian smoothing radius of 400 km. As an extended singular spectrum analysis (SSA), MSSA is more flexible to deal with multivariate time-series in terms of estimating periodic components and trend, reducing noise and identifying patterns of similar spatiotemporal behaviour thanks to the data-adaptive nature of the base functions. Combining MSSA and Gaussian filter can not only obviously remove the north-south striping errors in the GRACE solutions but also reduce the leakage errors, which can increase the signal-to-noise ratio by comparing with the traditional procedure, that is, empirical decorrelation method followed with the Gaussian filtering. The spatiotemporal characteristics of TWS changes in Xinjiang were validated against the Global Land Dynamics Assimilation System, the Climate Prediction Center and in-situ precipitation data. The water storage in Xinjiang shows the relatively large fluctuation from 2003 January to 2013 December, with a drop from 2006 January to 2008 December due to the drought event and an obvious rise from 2009 January to 2010 December because of the high precipitation. Spatially, the TWS has been increasing in the south Xinjiang, but decreasing in the north Xinjiang. The minimum rate of water storage change is -4.4 mm yr-1 occurring in the central Tianshan Mountain.

  17. Fabrication of Activated Rice Husk Charcoal by Slip Casting as a Hybrid Material for Water Filter Aid

    International Nuclear Information System (INIS)

    Tuaprakone, T; Wongphaet, N; Wasanapiarnpong, T

    2011-01-01

    Activated charcoal has been widely used as an odor absorbent in household and water purification industry. Filtration equipment for drinking water generally consists of four parts, which are microporous membrane (porous alumina ceramic or diatomite, or porous polymer), odor absorbent (activated carbon), hard water treatment (ion exchange resin), and UV irradiation. Ceramic filter aid is usually prepared by slip casting of alumina or diatomite. The membrane offers high flux, high porosity and maximum pore size does not exceed 0.3 μm. This study investigated the fabrication of hybrid activated charcoal tube for water filtration and odor absorption by slip casting. The suitable rice husk charcoal and water ratio was 48 to 52 wt% by weight with 1.5wt% (by dry basis) of CMC binder. The green rice husk charcoal bodies were dried and fired between 700-900 deg. C in reduction atmosphere. The resulting prepared slip in high speed porcelain pot for 60 min and sintered at 700 deg. C for 1 h showed the highest specific surface area as 174.95 m 2 /g. The characterizations of microstructure and pore size distribution as a function of particle size were investigated.

  18. Fabrication of Activated Rice Husk Charcoal by Slip Casting as a Hybrid Material for Water Filter Aid

    Science.gov (United States)

    Tuaprakone, T.; Wongphaet, N.; Wasanapiarnpong, T.

    2011-04-01

    Activated charcoal has been widely used as an odor absorbent in household and water purification industry. Filtration equipment for drinking water generally consists of four parts, which are microporous membrane (porous alumina ceramic or diatomite, or porous polymer), odor absorbent (activated carbon), hard water treatment (ion exchange resin), and UV irradiation. Ceramic filter aid is usually prepared by slip casting of alumina or diatomite. The membrane offers high flux, high porosity and maximum pore size does not exceed 0.3 μm. This study investigated the fabrication of hybrid activated charcoal tube for water filtration and odor absorption by slip casting. The suitable rice husk charcoal and water ratio was 48 to 52 wt% by weight with 1.5wt% (by dry basis) of CMC binder. The green rice husk charcoal bodies were dried and fired between 700-900 °C in reduction atmosphere. The resulting prepared slip in high speed porcelain pot for 60 min and sintered at 700 °C for 1 h showed the highest specific surface area as 174.95 m2/g. The characterizations of microstructure and pore size distribution as a function of particle size were investigated.

  19. Fabrication of Activated Rice Husk Charcoal by Slip Casting as a Hybrid Material for Water Filter Aid

    Energy Technology Data Exchange (ETDEWEB)

    Tuaprakone, T; Wongphaet, N; Wasanapiarnpong, T, E-mail: tonggogo@hotmail.com [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand)

    2011-04-15

    Activated charcoal has been widely used as an odor absorbent in household and water purification industry. Filtration equipment for drinking water generally consists of four parts, which are microporous membrane (porous alumina ceramic or diatomite, or porous polymer), odor absorbent (activated carbon), hard water treatment (ion exchange resin), and UV irradiation. Ceramic filter aid is usually prepared by slip casting of alumina or diatomite. The membrane offers high flux, high porosity and maximum pore size does not exceed 0.3 {mu}m. This study investigated the fabrication of hybrid activated charcoal tube for water filtration and odor absorption by slip casting. The suitable rice husk charcoal and water ratio was 48 to 52 wt% by weight with 1.5wt% (by dry basis) of CMC binder. The green rice husk charcoal bodies were dried and fired between 700-900 deg. C in reduction atmosphere. The resulting prepared slip in high speed porcelain pot for 60 min and sintered at 700 deg. C for 1 h showed the highest specific surface area as 174.95 m{sup 2}/g. The characterizations of microstructure and pore size distribution as a function of particle size were investigated.

  20. Water level response measurement in a steel cylindrical liquid storage tank using image filter processing under seismic excitation

    Science.gov (United States)

    Kim, Sung-Wan; Choi, Hyoung-Suk; Park, Dong-Uk; Baek, Eun-Rim; Kim, Jae-Min

    2018-02-01

    Sloshing refers to the movement of fluid that occurs when the kinetic energy of various storage tanks containing fluid (e.g., excitation and vibration) is continuously applied to the fluid inside the tanks. As the movement induced by an external force gets closer to the resonance frequency of the fluid, the effect of sloshing increases, and this can lead to a serious problem with the structural stability of the system. Thus, it is important to accurately understand the physics of sloshing, and to effectively suppress and reduce the sloshing. Also, a method for the economical measurement of the water level response of a liquid storage tank is needed for the exact analysis of sloshing. In this study, a method using images was employed among the methods for measuring the water level response of a liquid storage tank, and the water level response was measured using an image filter processing algorithm for the reduction of the noise of the fluid induced by light, and for the sharpening of the structure installed at the liquid storage tank. A shaking table test was performed to verify the validity of the method of measuring the water level response of a liquid storage tank using images, and the result was analyzed and compared with the response measured using a water level gauge.

  1. [Determination of metals in waste bag filter of steel works by microwave digestion-flame atomic absorption spectrometry].

    Science.gov (United States)

    Ning, Xun-An; Zhou, Yun; Liu, Jing-Yong; Wang, Jiang-Hui; Li, Lei; Ma, Xiao-Guo

    2011-09-01

    A method of microwave digestion technique-flame atomic absorption spectrometry was proposed to determine the total contents of Cu, Zn, Pb, Cd, Cr and Ni in five different kinds of waste bag filters from a steel plant. The digestion effects of the six acid systems on the heavy metals digestion were studied for the first time. The relative standard deviation (RSD) of the method was between 1.02% and 9.35%, and the recovery rates obtained by standard addition method ranged from 87.7% to 105.6%. The results indicated that the proposed method exhibited the advantages of simplicity, speediness, accuracy and repeatability, and it was suitable for determining the metal elements of the waste bag filter. The results also showed that different digestion systems should be used according to different waste bag filters. The waste bag filter samples from different production processes had different metal elements content. The Pb and Zn were the highest in the waste bag filters, while the Cu, Ni, Cd and Cr were relatively lower. These determination results provided the scientific data for further treatment and disposal of the waste bag filter.

  2. Comparison of the bacterial removal performance of silver nanoparticles and a polymer based quaternary amine functiaonalized silsesquioxane coated point-of-use ceramic water filters.

    Science.gov (United States)

    Zhang, Hongyin; Oyanedel-Craver, Vinka

    2013-09-15

    This study compares the disinfection performance of ceramic water filters impregnated with two antibacterial compounds: silver nanoparticles and a polymer based quaternary amine functiaonalized silsesquioxane (poly(trihydroxysilyl) propyldimethyloctadecyl ammonium chloride (TPA)). This study evaluated these compounds using ceramic disks manufactures with clay obtained from a ceramic filter factory located in San Mateo Ixtatan, Guatemala. Instead of using full size ceramic water filters, manufactured 6.5 cm diameter ceramic water filter disks were used. Results showed that TPA can achieve a log bacterial reduction value of 10 while silver nanoparticles reached up to 2 log reduction using a initial concentration of bacteria of 10(10)-10(11)CFU/ml. Similarly, bacterial transport demonstrated that ceramic filter disks painted with TPA achieved a bacterial log reduction value of 6.24, which is about 2 log higher than the values obtained for disks painted with silver nanoparticles (bacterial log reduction value: 4.42). The release of both disinfectants from the ceramic materials to the treated water was determined measuring the effluent concentrations in each test performed. Regarding TPA, about 3% of the total mass applied to the ceramic disks was released in the effluent over 300 min, which is slightly lower than the release percentage for silver nanoparticles (4%). This study showed that TPA provides a comparable disinfection performance than silver nanoparticles in ceramic water filter. Another advantage of using TPA is the cost as the price of TPA is considerable lower than silver nanoparticles. In spite of the use of TPA in several medical related products, there is only partial information regarding the health risk associated with the ingestion of this compound. Additional long-term toxicological information for TPA should be evaluated before its future application in ceramic water filters. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. THE IMPROVEMENT OF LOW-WASTE TECHNOLOGIES OF WORKING BODY OF WATER PREPARATION AT THERMAL AND NUCLEAR POWER PLANTS

    Directory of Open Access Journals (Sweden)

    K. D. Rymasheuskaya

    2017-01-01

    Full Text Available In the present work the main directions of water desalination technologies improving have been analyzed. Possible techniques of high-quality treatment of water that enable the reduction of amounts of environmentally hazardous substances to be discharged into the hydrosphere are indicated. The purpose of the work was to improve the ecological efficiency and the effectiveness of water treatment equipment at heat power plants when designing new and the modernizing existing water treatment schemes. In order to achieve this goal the following problems have been solved: the one of analyzing the main directions of the improvement of technologies of working body of water preparation at thermal and nuclear power plants; of analyzing the main directions of reduction of total volume of highly mineralized power plant wastewaters; of developing the technological scheme of recycling of concentrate of membrane installations and regenerants of ionite filters in acid and alkali; of developing the technological scheme of transformation of the sludge in pre-processing waste into valuable commodity products. The results of research can be applied for the design of new and the modernization of existing water treatment installations of thermal and nuclear power plants. It will enable to reduce considerably the use of natural water and the amount of chemicals added as well as the volume of wastewater and the concentration of dissolved solids in it. As a consequence, the negative impact of thermal and nuclear power plants on the hydrosphere will be reduced. 

  4. The effectiveness of the use of filter on the tilapia growth performance, number of Nitrosomonas sp., and water quality in aquaponics systems

    OpenAIRE

    Yuli Andriani; , Zahidah; Yayat Dhahiyat; Ujang Subhan; Irfan Zidni; Rusky Intan Pratama; Nadia Purnamasari Gumay

    2018-01-01

    ABSTRACT This study aims to determine the most effective type of living filter media for the bacteria Nitrosomonas sp. in order to improve water quality in aquaponics systems. The method used in this study was completely randomized design, consisting of five treatments and each was repeated three times. The treatments were: A (without addition of filter media), B (addition of palm fibers, silica sand, and activated carbon), C (addition of palm fibers, silica sand, gravel, and activated carbon...

  5. A Randomized Controlled Trial to Assess the Impact of Ceramic Water Filters on Prevention of Diarrhea and Cryptosporidiosis in Infants and Young Children-Western Kenya, 2013.

    Science.gov (United States)

    Morris, Jamae Fontain; Murphy, Jennifer; Fagerli, Kirsten; Schneeberger, Chandra; Jaron, Peter; Moke, Fenny; Juma, Jane; Ochieng, J Ben; Omore, Richard; Roellig, Dawn; Xiao, Lihua; Priest, Jeffrey W; Narayanan, Jothikumar; Montgomery, Joel; Hill, Vince; Mintz, Eric; Ayers, Tracy L; O'Reilly, Ciara E

    2018-04-02

    Cryptosporidium is a leading cause of diarrhea among Kenyan infants. Ceramic water filters (CWFs) are used for household water treatment. We assessed the impact of CWFs on diarrhea, cryptosporidiosis prevention, and water quality in rural western Kenya. A randomized, controlled intervention trial was conducted in 240 households with infants 4-10 months old. Twenty-six weekly household surveys assessed infant diarrhea and health facility visits. Stool specimens from infants with diarrhea were examined for Cryptosporidium . Source water, filtered water, and filter retentate were tested for Cryptosporidium and/or microbial indicators. To estimate the effect of CWFs on health outcomes, logistic regression models using generalized estimating equations were performed; odds ratios (ORs) and 95% confidence intervals (CIs) are reported. Households reported using surface water (36%), public taps (29%), or rainwater (17%) as their primary drinking water sources, with no differences in treatment groups. Intervention households reported less diarrhea (7.6% versus 8.9%; OR: 0.86 [0.64-1.16]) and significantly fewer health facility visits for diarrhea (1.0% versus 1.9%; OR: 0.50 [0.30-0.83]). In total, 15% of intervention and 12% of control stools yielded Cryptosporidium ( P = 0.26). Escherichia coli was detected in 93% of source water samples; 71% of filtered water samples met World Health Organization recommendations of filter rinses following passage of large volumes of source water. Water quality was improved among CWF users; however, the short study duration and small sample size limited our ability to observe reductions in cryptosporidiosis.

  6. Adaptive Kalman Filter Based on Adjustable Sampling Interval in Burst Detection for Water Distribution System

    OpenAIRE

    Doo Yong Choi; Seong-Won Kim; Min-Ah Choi; Zong Woo Geem

    2016-01-01

    Rapid detection of bursts and leaks in water distribution systems (WDSs) can reduce the social and economic costs incurred through direct loss of water into the ground, additional energy demand for water supply, and service interruptions. Many real-time burst detection models have been developed in accordance with the use of supervisory control and data acquisition (SCADA) systems and the establishment of district meter areas (DMAs). Nonetheless, no consideration has been given to how frequen...

  7. Effect of water-to-cement ratio and curing method on the strength, shrinkage and slump of the biosand filter concrete body.

    Science.gov (United States)

    Chan, Nicole; Young-Rojanschi, Candice; Li, Simon

    2018-03-01

    The biosand filter is a household-level water treatment technology used globally in low-resource settings. As of December 2016, over 900,000 biosand filters had been implemented in 60 countries around the world. Local, decentralized production is one of the main advantages of this technology, but it also creates challenges, especially in regards to quality control. Using the current recommended proportions for the biosand filter concrete mix, slump was measured at water-to-cement ratios of 0.51, 0.64 and 0.76, with two replicates for each level. Twenty-eight-day strength was tested on four replicate cylinders, each at water-to-cement ratios of 0.51, 0.59, 0.67 and 0.76. Wet curing and dry curing were compared for 28-day strength and for their effect on shrinkage. Maximum strength occurred at water-to-cement ratios of 0.51-0.59, equivalent to 8-9.3 L water for a full-scale filter assuming saturated media, corresponding to a slump class of S1 (10-40 mm). Wet curing significantly improved strength of the concrete mix and reduced shrinkage. Quality control measures such as the slump test can significantly improve the quality within decentralized production of biosand filters, despite localized differences in production conditions.

  8. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 1: nonuniform infiltration and soil water redistribution

    Science.gov (United States)

    Muñoz-Carpena, Rafael; Lauvernet, Claire; Carluer, Nadia

    2018-01-01

    Vegetation buffers like vegetative filter strips (VFSs) are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT) that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To simulate VFS infiltration under realistic rainfall conditions with WT, we propose a generic infiltration solution (Shallow Water table INfiltration algorithm: SWINGO) based on a combination of approaches by Salvucci and Entekhabi (1995) and Chu (1997) with new integral formulae to calculate singular times (time of ponding, shift time, and time to soil profile saturation). The algorithm was tested successfully on five distinct soils, both against Richards's numerical solution and experimental data in terms of infiltration and soil moisture redistribution predictions, and applied to study the combined effects of varying WT depth, soil type, and rainfall intensity and duration. The results show the robustness of the algorithm and its ability to handle various soil hydraulic functions and initial nonponding conditions under unsteady rainfall. The effect of a WT on infiltration under ponded conditions was found to be effectively decoupled from surface infiltration and excess runoff processes for depths larger than 1.2 to 2 m, being shallower for fine soils and shorter events. For nonponded initial conditions, the influence of WT depth also varies with rainfall intensity. Also, we observed that soils with a marked air entry (bubbling pressure) exhibit a distinct behavior with WT near the surface. The good performance, robustness, and flexibility of SWINGO supports its broader use to study WT effects on surface runoff, infiltration, flooding, transport, ecological, and land use processes. SWINGO is

  9. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 1: nonuniform infiltration and soil water redistribution

    Directory of Open Access Journals (Sweden)

    R. Muñoz-Carpena

    2018-01-01

    Full Text Available Vegetation buffers like vegetative filter strips (VFSs are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To simulate VFS infiltration under realistic rainfall conditions with WT, we propose a generic infiltration solution (Shallow Water table INfiltration algorithm: SWINGO based on a combination of approaches by Salvucci and Entekhabi (1995 and Chu (1997 with new integral formulae to calculate singular times (time of ponding, shift time, and time to soil profile saturation. The algorithm was tested successfully on five distinct soils, both against Richards's numerical solution and experimental data in terms of infiltration and soil moisture redistribution predictions, and applied to study the combined effects of varying WT depth, soil type, and rainfall intensity and duration. The results show the robustness of the algorithm and its ability to handle various soil hydraulic functions and initial nonponding conditions under unsteady rainfall. The effect of a WT on infiltration under ponded conditions was found to be effectively decoupled from surface infiltration and excess runoff processes for depths larger than 1.2 to 2 m, being shallower for fine soils and shorter events. For nonponded initial conditions, the influence of WT depth also varies with rainfall intensity. Also, we observed that soils with a marked air entry (bubbling pressure exhibit a distinct behavior with WT near the surface. The good performance, robustness, and flexibility of SWINGO supports its broader use to study WT effects on surface runoff, infiltration, flooding, transport, ecological, and land use processes

  10. Working group report on water resources, supply and demand

    International Nuclear Information System (INIS)

    Marta, T.J.

    1990-01-01

    A summary is presented of the issues discussed, and the conclusions and recommendations of a working group on water resources, supply and demand. The issues were grouped into the categories of detecting climatic change and water impacts, simulating potential impacts, and responding to potential impacts. The workshop groups achieved consensus on the following points: the physics of global warming and climatic change have been satifactorily proven; there appears to be some evidence of climatic change and a signal could soon be detected; policy decisions and strategic plans for climatic change and its potential impacts are needed immediately; and targets and priorities for decison making should be identified and addressed immediately. Three top-priority issues are the identification of indicators for the detection of climatic change impacts on hydrology, determining response to climate-related change, and evaluation of design criteria. Better information on regional climate and hydrology under conditions of global warming is needed before design criteria could be altered

  11. Problems of Nitrogen at Central Municipal Water Works in Ostrava

    Directory of Open Access Journals (Sweden)

    Praus Petr

    2003-09-01

    Full Text Available Nitrogen is very important nutrient and must be removed during wastewater treatment process. The presented article describes the situation of nitrogen removal at the Central Municipal Water Works in Ostrava. At present, this biological sewage plant operates with only 45% nitrogen removal efficiency. The current three corridor denitrification-nitrification (D-N system is planed to be reconstructed. One of several solution is modification of the activation tank into four step D-N system that could be completed by postdenitrification in the redundant clarifiers.In this paper the analytical methods, used for determination of nitrogen compounds in waste waters, are described as well. Only sufficiently precise and accurate methods must be selected and that is why the standardized or fully validated procedures are preferred. Laboratory results are used for monitoring of treatment process and for making of important technological decisions. For this purpose, introduction of the quality control and quality assurance system into laboratory practise is desired.

  12. Expanding the use of polymeric ionic liquids in headspace solid-phase microextraction: Determination of ultraviolet filters in water samples.

    Science.gov (United States)

    Trujillo-Rodríguez, María J; Nan, He; Anderson, Jared L

    2018-03-09

    Three crosslinked polymeric ionic liquid (PIL) sorbent coatings were used in headspace solid-phase microextraction for the determination of a group of ultraviolet filters. The developed crosslinked PIL-based materials include two polycations and a double confined PIL. The method, in combination with gas chromatography-mass spectrometry, is simple, solvent free, and does not require of any derivatization step. After proper optimization of the methodologies with each developed fiber, the analytical performance was compared with a commercial polyacrylate fiber. A study of the normalized calibration slopes, obtained by dividing the calibration slope of each analyte by the coating volume, revealed that the crosslinked fibers can be used as alternatives to commercial fibers for the determination of the selected group of compounds. In particular, the coating nature of the PIL containing the 1-vinylbenzyl-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide IL as monomer and the 1,12-di(3-vinylbenzylimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide IL as crosslinker is the most suitable for the extraction of the selected compounds despite their coating volume, being 3.6 times lower than the commercial polyacrylate fiber. For this fiber, wide linear ranges, correlation coefficients higher than 0.990, limits of detection ranging from 2.8 ng L -1 to 26 ng L -1 and relative standard deviations ranging from 2.5 to 15% were achieved. Finally, all proposed PIL-based fibers were applied towards the analysis of tap water, pool water and lake water, with the majority of the ultraviolet filters being detected and quantified in the last two types of samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. The effectiveness of the use of filter on the tilapia growth performance, number of Nitrosomonas sp., and water quality in aquaponics systems

    Directory of Open Access Journals (Sweden)

    Yuli Andriani

    2018-01-01

    Full Text Available ABSTRACT This study aims to determine the most effective type of living filter media for the bacteria Nitrosomonas sp. in order to improve water quality in aquaponics systems. The method used in this study was completely randomized design, consisting of five treatments and each was repeated three times. The treatments were: A (without addition of filter media, B (addition of palm fibers, silica sand, and activated carbon, C (addition of palm fibers, silica sand, gravel, and activated carbon, D (addition of palm fibers, silica sand, rocks, and activated carbon, and E (addition of palm fibers, silica sand, bioball, and activated carbon. Parameters measured were: 1 the number of Nitrosomonas bacteria, 2 water quality (ammonia, nitrate, and phosphate; and, 3 productivity of fish and Chinese spinach. Data were analyzed using a descriptive method. The findings show that the highest number of bacteria was found in treatment E, 9.29×105 CFU/mL on the bioball filter media and 4.43×105 CFU/mL in rearing tanks. The best water quality was in treatment B, with a concentration of ammonia of 0.17 mg/L, nitrate of 0.33 mg/L, and phosphate of 0.54 mg/L. Plant productivity was the best in treatment B in which the average length and weight reach 48.1 cm and 11.1 grams of plant/week, respectively. The best fish growth was seen in treatment C with an absolute growth rate of 4.4 grams and a specific growth rate of 1.9%/day. The recommended filter was made of Arenga pinnata fibers, silica sand, gravels, and active carbon of about 2 cm thick each.The results showed that the type of filter on the aquaponic system had an effect on the amount of Nitrosomonas sp. in water, water quality, and the productivity of Chinese spinach.Keywords: aquaponics, filter, water quality, Nitrosomonas sp.ABSTRAKPenelitian ini bertujuan untuk menentukan jenis filter yang paling efektif sebagai media hidup bakteri Nitrosomonas sp. sehingga menghasilkan kualitas air yang baik dalam sistem

  14. Topical and working papers on heavy water requirements and availability

    International Nuclear Information System (INIS)

    The documents included in this report are: Heavy water requirements and availability; technological infrastructure for heavy water plants; heavy water plant siting; hydrogen and methane availability; economics of heavy water production; monothermal, water fed heavy water process based on the ammonia/hydrogen isotopic exchange; production strategies to meet demand projections; hydrogen availability; deuterium sources; the independent UHDE heavy water process

  15. Application of the extended Kalman filtering for the estimation of core coolant flow rate in pressurized water reactors

    International Nuclear Information System (INIS)

    Shieh, D.J.; Upadhyaya, B.R.

    1986-01-01

    In-core neutron detector and core-exit temperature signals in a pressurized water reactor (PWR) satisfy the condition of observability of the core dynamic system, and can be used to estimate nonmeasurable state variables and model parameters. The extension of the Kalman filtering technique is very useful for direct parameter estimation. This approach is applied to the determination of core coolant mass flow rate in PWRs and is evaluated using in-core measurements at the Loss-of-Fluid Test (LOFT) reactor. The influence of model uncertainties on the estimation accuracy was studied using the ambiguity function analysis. A sequential discretization method was developed to achieve faster convergence to the true value, avoiding model discretization at each sample point. The performance of the extended Kalman filter and the computational innovations were evaluated using a reduced order core dynamic model of the LOFT reactor and random data simulation. The technique was then applied to the determination of LOFT core coolant flow rate from operational data at 100% and 65% flow conditions

  16. The effect of algal and bacterial filters on sea water quality during ...

    African Journals Online (AJOL)

    quality changes in bacterial and algal filtration systems over a two month period. Juvenile ..... of the algae, prawns and micro-organisms (decomposition of excess food and .... Cultivation of marine organisms: Water quality management and ...

  17. Bias aware Kalman filters

    DEFF Research Database (Denmark)

    Drecourt, J.-P.; Madsen, H.; Rosbjerg, Dan

    2006-01-01

    This paper reviews two different approaches that have been proposed to tackle the problems of model bias with the Kalman filter: the use of a colored noise model and the implementation of a separate bias filter. Both filters are implemented with and without feedback of the bias into the model state....... The colored noise filter formulation is extended to correct both time correlated and uncorrelated model error components. A more stable version of the separate filter without feedback is presented. The filters are implemented in an ensemble framework using Latin hypercube sampling. The techniques...... are illustrated on a simple one-dimensional groundwater problem. The results show that the presented filters outperform the standard Kalman filter and that the implementations with bias feedback work in more general conditions than the implementations without feedback. 2005 Elsevier Ltd. All rights reserved....

  18. Quantifying Methane Flux from a Prominent Seafloor Crater with Water Column Imagery Filtering and Bubble Quantification Techniques

    Science.gov (United States)

    Mitchell, G. A.; Gharib, J. J.; Doolittle, D. F.

    2015-12-01

    Methane gas flux from the seafloor to atmosphere is an important variable for global carbon cycle and climate models, yet is poorly constrained. Methodologies used to estimate seafloor gas flux commonly employ a combination of acoustic and optical techniques. These techniques often use hull-mounted multibeam echosounders (MBES) to quickly ensonify large volumes of the water column for acoustic backscatter anomalies indicative of gas bubble plumes. Detection of these water column anomalies with a MBES provides information on the lateral distribution of the plumes, the midwater dimensions of the plumes, and their positions on the seafloor. Seafloor plume locations are targeted for visual investigations using a remotely operated vehicle (ROV) to determine bubble emission rates, venting behaviors, bubble sizes, and ascent velocities. Once these variables are measured in-situ, an extrapolation of gas flux is made over the survey area using the number of remotely-mapped flares. This methodology was applied to a geophysical survey conducted in 2013 over a large seafloor crater that developed in response to an oil well blowout in 1983 offshore Papua New Guinea. The site was investigated by multibeam and sidescan mapping, sub-bottom profiling, 2-D high-resolution multi-channel seismic reflection, and ROV video and coring operations. Numerous water column plumes were detected in the data suggesting vigorously active vents within and near the seafloor crater (Figure 1). This study uses dual-frequency MBES datasets (Reson 7125, 200/400 kHz) and ROV video imagery of the active hydrocarbon seeps to estimate total gas flux from the crater. Plumes of bubbles were extracted from the water column data using threshold filtering techniques. Analysis of video images of the seep emission sites within the crater provided estimates on bubble size, expulsion frequency, and ascent velocity. The average gas flux characteristics made from ROV video observations is extrapolated over the number

  19. Emergency Response Proficiency Test for Japanese Laboratories: Determination of Selected Radionuclides in Water, Soil, Vegetation and Aerosol Filters

    International Nuclear Information System (INIS)

    2013-01-01

    Reliable determination of natural and artificial radionuclides in environmental samples is necessary for compliance with radiation protection and environmental regulations. The IAEA assists Member State laboratories in maintaining and improving their readiness in this regard by producing reference materials, by developing standardized analytical methods, and by conducting interlaboratory comparisons and proficiency tests as tools for quality control. To fulfil this obligation and ensure a reliable, rapid and consistent worldwide response, the IAEA Terrestrial Environment Laboratory in Seibersdorf, Austria, organizes interlaboratory comparisons and proficiency tests. In addition, the IAEA coordinates the worldwide network of Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA). After the accident at the Fukushima Daiichi nuclear power plant in March 2011, Japan requested the IAEA to organize an emergency response proficiency test for Japanese laboratories with the aim of assessing their capacity to rapidly and accurately measure radionuclides in environmental samples. The IAEA responded to the request by assembling a special sample set covering the main environmental samples and radionuclides of interest in the case of a nuclear emergency situation. Water, soil, vegetation and aerosol filter samples were made available to Japanese laboratories for analysis by gamma ray spectrometry. This report presents the results of the IAEA-TEL-2011-08 emergency response proficiency test for Japanese laboratories on the determination of selected radionuclides in water, soil, vegetation and aerosol filters. The report includes descriptions of the methodologies and data evaluation approach used, as well as summary evaluations of each radionuclide and individual evaluation reports of each laboratory. This proficiency test was designed to identify analytical problems and to support Member State laboratories in their efforts to improve the quality of

  20. Dynamic beam filtering for miscentered patients.

    Science.gov (United States)

    Mao, Andrew; Shyr, William; Gang, Grace J; Stayman, J Webster

    2018-02-01

    Accurate centering of the patient within the bore of a CT scanner takes time and is often difficult to achieve precisely. Patient miscentering can result in significant dose and image noise penalties with the use of traditional bowtie filters. This work describes a system to dynamically position an x-ray beam filter during image acquisition to enable more consistent image performance and potentially lower dose needed for CT imaging. We propose a new approach in which two orthogonal low-dose scout images are used to estimate a parametric model of the object describing its shape, size, and location within the field of view (FOV). This model is then used to compute an optimal filter motion profile by minimizing the variance of the expected detector fluence for each projection. Dynamic filtration was implemented on a cone-beam CT (CBCT) test bench using two different physical filters: 1) an aluminum bowtie and 2) a structured binary filter called a multiple aperture device (MAD). Dynamic filtration performance was compared to a static filter in studies of dose and reconstruction noise as a function of the degree of miscentering of a homogeneous water phantom. Estimated filter trajectories were found to be largely sinusoidal with an amplitude proportional to the amount of miscentering. Dynamic filtration demonstrated an improved ability to keep the spatial distribution of dose and reconstruction noise at baseline levels across varying levels of miscentering, reducing the maximum noise and dose deviation from 53% to 15% and 42% to 14% respectively for the bowtie filter, and 25% to 8% and 24% to 15% respectively for the MAD filter. Dynamic positioning of beam filters during acquisition improves dose utilization and image quality over static filters for miscentered patients. Such dynamic filters relax positioning requirements and have the potential to reduce set-up time and lower dose requirements.

  1. Activated soil filters for removal of biocides from contaminated run-off and waste-waters

    DEFF Research Database (Denmark)

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael

    2011-01-01

    -Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone). However, this removal is a considerable improvement compared to direct discharge into surface waters or infiltration into soil without appropriate removal. In the last experiment the removal efficiencies of the different layers were studied. Though the peat layer...

  2. Multifunctional Silver Coated E-33/Iron Oxide Water Filters: Inhibition of Biofilm Growth and Arsenic Removal

    Science.gov (United States)

    Bayoxide® E33 (E-33, Goethite) is a widely used commercial material for arsenic adsorption. It is a mixture of iron oxyhydroxide and oxides. E-33 is primarily used to remove arsenic from water and to a lesser extent, other anions, but generally lacks multifunctuality. It is a non...

  3. On-line measurement of oil contaminants in water by filter-based infrared analyzers

    International Nuclear Information System (INIS)

    Niemelae, P.

    1994-01-01

    The properties of a dedicated infrared analyzer for on-line measurement of the oil content of water, the Oili analyzer, are evaluated theoretically and with laboratory measurements. The analyzer was originally developed for controlling the discharge of ballast and bilge water from oil tankers and more than 200 such instruments have now been supplied for that purpose, representing about 10 % of the total market. Some technical improvements are suggested, and the improved instrument is shown to be capable of measuring oil in water to an accuracy of +- 20 % down to a detection limit of +5-10 ppm in the presence of high concentrations of interfering components and under varying environmental conditions. This opens up new potential applications for the instrument, e.g. the monitoring of water discharges from oil and gas production platforms. The infrared analyzer responds only to the dispersed oil fraction, and if the dissolved fraction is of interest as well, the instrument must be equipped with a UV option, as suggested here

  4. Laser-induced breakdown spectroscopy (LIBS) analysis of calcium ions dissolved in water using filter paper substrates: an ideal internal standard for precision improvement.

    Science.gov (United States)

    Choi, Daewoong; Gong, Yongdeuk; Nam, Sang-Ho; Han, Song-Hee; Yoo, Jonghyun; Lee, Yonghoon

    2014-01-01

    We report an approach for selecting an internal standard to improve the precision of laser-induced breakdown spectroscopy (LIBS) analysis for determining calcium (Ca) concentration in water. The dissolved Ca(2+) ions were pre-concentrated on filter paper by evaporating water. The filter paper was dried and analyzed using LIBS. By adding strontium chloride to sample solutions and using a Sr II line at 407.771 nm for the intensity normalization of Ca II lines at 393.366 or 396.847 nm, the analysis precision could be significantly improved. The Ca II and Sr II line intensities were mapped across the filter paper, and they showed a strong positive shot-to-shot correlation with the same spatial distribution on the filter paper surface. We applied this analysis approach for the measurement of Ca(2+) in tap, bottled, and ground water samples. The Ca(2+) concentrations determined using LIBS are in good agreement with those obtained from flame atomic absorption spectrometry. Finally, we suggest a homologous relation of the strongest emission lines of period 4 and 5 elements in groups IA and IIA based on their similar electronic structures. Our results indicate that the LIBS can be effectively applied for liquid analysis at the sub-parts per million level with high precision using a simple drying of liquid solutions on filter paper and the use of the correct internal standard elements with the similar valence electronic structure with respect to the analytes of interest.

  5. Reconsidering 'appropriate technology': the effects of operating conditions on the bacterial removal performance of two household drinking-water filter systems

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, Jill [Harvard School of Public Health, Boston, MA (United States); Murcott, Susan [Massachusetts Institute of Technology, Cambridge, MA (United States); Ezzati, Majid [Harvard School of Public Health, Boston, MA (United States)

    2007-04-01

    We examined the performance of two household water treatment and safe storage (HWTS) systems, the Danvor plastic biosand filter and the Potters for Peace Filtron ceramic filter, under ideal as well as modified operating conditions using systematic and comparable measurements. The operating variables for the biosand filter were (i) pause times between filtration runs (ii) water-dosing volumes and (iii) the effluent volume at which a filtered water sample was collected. For the ceramic filter we examined overflow filtration versus standard filtration. We used the bacterial indicators of total coliforms and Escherichia coli to quantify microbiological removal. With the biosand filter, a 12 h pause time had significantly higher total coliform removal than a 36 h pause time at the 20 l collection point (79.1% versus 73.7%; p < 0.01) and borderline significance at the 10 l collection point (81.0% versus 78.3%; p = 0.07). High-volume filtration (20 l) had significantly lower total coliform removal efficacy than low-volume (10 l) filtration at the 10 l collection point (81.0% versus 84.2%; p = 0.03). We observed a decreasing trend in total coliform removal by sample collection volume with the highest removal efficacy at the 5 l sample collection point (versus at the 10 and 20 l collection points). Using the ceramic filter, mean total coliform and E. coli removal were significantly lower (p < 0.01) in overflow filtration than in standard filtration. The findings indicate that operating conditions can reduce the effectiveness of the systems in a field-based setting and increase environmental risk exposure.

  6. Reconsidering 'appropriate technology': the effects of operating conditions on the bacterial removal performance of two household drinking-water filter systems

    International Nuclear Information System (INIS)

    Baumgartner, Jill; Murcott, Susan; Ezzati, Majid

    2007-01-01

    We examined the performance of two household water treatment and safe storage (HWTS) systems, the Danvor plastic biosand filter and the Potters for Peace Filtron ceramic filter, under ideal as well as modified operating conditions using systematic and comparable measurements. The operating variables for the biosand filter were (i) pause times between filtration runs (ii) water-dosing volumes and (iii) the effluent volume at which a filtered water sample was collected. For the ceramic filter we examined overflow filtration versus standard filtration. We used the bacterial indicators of total coliforms and Escherichia coli to quantify microbiological removal. With the biosand filter, a 12 h pause time had significantly higher total coliform removal than a 36 h pause time at the 20 l collection point (79.1% versus 73.7%; p < 0.01) and borderline significance at the 10 l collection point (81.0% versus 78.3%; p = 0.07). High-volume filtration (20 l) had significantly lower total coliform removal efficacy than low-volume (10 l) filtration at the 10 l collection point (81.0% versus 84.2%; p = 0.03). We observed a decreasing trend in total coliform removal by sample collection volume with the highest removal efficacy at the 5 l sample collection point (versus at the 10 and 20 l collection points). Using the ceramic filter, mean total coliform and E. coli removal were significantly lower (p < 0.01) in overflow filtration than in standard filtration. The findings indicate that operating conditions can reduce the effectiveness of the systems in a field-based setting and increase environmental risk exposure

  7. Model-Based Water Wall Fault Detection and Diagnosis of FBC Boiler Using Strong Tracking Filter

    Directory of Open Access Journals (Sweden)

    Li Sun

    2014-01-01

    Full Text Available Fluidized bed combustion (FBC boilers have received increasing attention in recent decades. The erosion issue on the water wall is one of the most common and serious faults for FBC boilers. Unlike direct measurement of tube thickness used by ultrasonic methods, the wastage of water wall is reconsidered equally as the variation of the overall heat transfer coefficient in the furnace. In this paper, a model-based approach is presented to estimate internal states and heat transfer coefficient dually from the noisy measurable outputs. The estimated parameter is compared with the normal value. Then the modified Bayesian algorithm is adopted for fault detection and diagnosis (FDD. The simulation results demonstrate that the approach is feasible and effective.

  8. Impacts of alum residues from Morton Jaffray Water Works on water quality and fish, Harare, Zimbabwe

    Science.gov (United States)

    Muisa, Norah; Hoko, Zvikomborero; Chifamba, Portia

    Metal pollution of freshwater due to human activities is a major problem confronting most urban centres in developing countries. This study determined the extent to which aluminium in the residues from Morton Jaffray Water Works in Harare were affecting the water quality of Manyame River and Lake Manyame. The study also measured aluminium bioaccumulation in Nile Tilapia ( Oreochromis niloticus) which is of importance to the commercial fisheries industry in Zimbabwe. Depth integrated water, and sediment grab samples and adult fish were collected per site in January and March, 2010. A total of six sites were selected on the Manyame River and in Lake Manyame. The levels of Total Aluminium (Al) were determined in sediments, water and fish tissues (liver, kidney, gill and muscle). Total solids, total dissolved solids, conductivity, pH, dissolved oxygen and temperature were also determined in water and residues. The texture of the sediments was also assessed. Aluminium concentration in water ranged from 2.19 mg/L to 68.93 mg/L during both sampling campaigns surpassing permissible maximum concentration limits of 0.087 to 0.75 mg/L suggested by the Environmental Protection Agency and African Union. The site upstream of the discharge point of the residues always had the lowest levels though it was higher than acceptable levels indicated above, thus suggesting the existence of other sources of aluminium in the catchment besides Morton Jaffray Water Works. However, there was a 10-fold and 100-fold increase in levels of aluminium in water and sediments, respectively, at the site 100 m downstream of the discharge point on the Manyame River. Mean aluminium concentrations in water and sediments at this site averaged 68.93 ± 61.74 mg/L and 38.18 ± 21.54 mg/L in water and 103.79 ± 55.96 mg/L and 131.84 ± 16.48 mg/L in sediments in sampling campaigns 1 and 2, respectively. These levels were significantly higher than levels obtained from all the other sites during both sampling

  9. Using a biological aerated filter to treat mixed water-borne volatile organic compounds and assessing its emissions

    Institute of Scientific and Technical Information of China (English)

    CHENG Wen-Hsi

    2009-01-01

    A biological aerated filter (BAF) was evaluated as a fixed-biofilm processes to remove water-borne volatile organic compounds (VOCs) from a multiple layer ceramic capacitor (MLCC) manufacturing plant in southern Taiwan.The components of VOC were identified to be toluene,1,2,4-trimethylbenzene,1,3,5-trimethylbenzene,bromodichloromethane and isopropanol (IPA).The full-scale BAF was constructed of two separate reactors in series,respectively using 10-cm and 15-cm diameter polypropylene balls as the packing materials and a successful preliminary bench-scale experiment was performed to feasibility.Performance results show that the BAF removed over 90% chemical oxygen demand (COD) from the influent with (1188 ± 605) mg/L of COD.A total organic loading of 2.76 kg biochemical oxygen demand (BOD)/(m~3 packing·d) was determined for the packed bed,in which the flow pattern approached that of a mixed flow.A limited VOC concentration of (0.97 ± 0.29) ppmv (as methane) was emitted from the BAF system.Moreover,the emission rate of VOC was calculated using the proposed formula,based on an air-water mass equilibrium relationship,and compared to the simulated results obtained using the Water 9 model.Both estimation approaches of calculation and model simulation using Water 9 evaluating VOC emissions reveal that 0.1% IPA (0.0031-0.0037 kg/d) was aerated into a gaseous phase,and 30% to 40% (0.006-0.008 kg/d) of the toluene was aerated.

  10. Performance evaluation of different filter media in turbidity removal from water by application of modified qualitative indices.

    Science.gov (United States)

    Gholikandi, G Badalians; Dehghanifard, E; Sepehr, M Noori; Torabian, A; Moalej, S; Dehnavi, A; Yari, Ar; Asgari, Ar

    2012-01-01

    Water filtration units have been faced problems in water turbidity removal related to their media, which is determined by qualitative indices. Moreover, Current qualitative indices such as turbidity and escaping particle number could not precisely determine the efficiency of the media in water filtration, so defining new indices is essential. In this study, the efficiency of Anthracite-Silica and LECA-Silica media in turbidity removal were compared in different operating condition by using modified qualitative indices. The pilot consisted of a filter column (one meter depth) which consisted of a layer of LECA (450 mm depth) and a layer of Silica sand (350 mm depth. Turbidities of 10, 20, and 30 NTU, coagulant concentrations of 4, 8, and 12 ppm and filtration rates of 10, 15, and 20 m/h were considered as variables. The LECA-Silica media is suitable media for water filtration. Averages of turbidity removal efficiencies in different condition for the LECA-Silica media were 85.8±5.37 percent in stable phase and 69.75±3.37 percent in whole operation phase, while the efficiency of total system were 98.31±0.63 and 94.49±2.97 percent, respectively. The LECA layer efficiency in turbidity removal was independent from filtration rates and due to its low head loss; LECA can be used as a proper medium for treatment plants. Results also showed that the particle index (PI) was a suitable index as a substitute for turbidity and EPN indices.

  11. Radioactive Air Emissions Notice of Construction for the 105-KW Basin integrated water treatment system filter vessel sparging vent

    Energy Technology Data Exchange (ETDEWEB)

    Kamberg, L.D.

    1998-02-23

    This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.07, for the Integrated Water Treatment System (IWTS) Filter Vessel Sparging Vent at 105-KW Basin. Additionally, the following description, and references are provided as the notices of startup, pursuant to 40 CFR 61.09(a)(1) and (2) in accordance with Title 40 Code of Federal Regulations, Part 61, National Emission Standards for Hazardous Air Pollutants. The 105-K West Reactor and its associated spent nuclear fuel (SNF) storage basin were constructed in the early 1950s and are located on the Hanford Site in the 100-K Area about 1,400 feet from the Columbia River. The 105-KW Basin contains 964 Metric Tons of SNF stored under water in approximately 3,800 closed canisters. This SNF has been stored for varying periods of time ranging from 8 to 17 years. The 105-KW Basin is constructed of concrete with an epoxy coating and contains approximately 1.3 million gallons of water with an asphaltic membrane beneath the pool. The IWTS, which has been described in the Radioactive Air Emissions NOC for Fuel Removal for 105-KW Basin (DOE/RL-97-28 and page changes per US Department of Energy, Richland Operations Office letter 97-EAP-814) will be used to remove radionuclides from the basin water during fuel removal operations. The purpose of the modification described herein is to provide operational flexibility for the IWTS at the 105-KW basin. The proposed modification is scheduled to begin in calendar year 1998.

  12. Backflushable filter insert

    International Nuclear Information System (INIS)

    Keith, R.C.; Vandenberg, T.; Randolph, M.C.; Lewis, T.B.; Gillis, P.J. Jr.

    1988-01-01

    Filter elements are mounted on a tube plate beneath an accumulator chamber whose wall is extended by skirt and flange to form a closure for the top of pressure vessel. The accumulator chamber is annular around a central pipe which serves as the outlet for filtered water passing from the filter elements. The chamber contains filtered compressed air from supply. Periodically the filtration of water is stopped and vessel is drained. Then a valve is opened, allowing the accumulated air to flow from chamber up a pipe and down pipe, pushing the filtered water from pipe back through the filter elements to clean them. The accumulator chamber is so proportioned, relative to the volume of the system communicating therewith during backflushing, that the equilibrium pressure during backflushing cannot exceed the pressure rating of the vessel. However a line monitors the pressure at the top of the vessel, and if it rises too far a bleed valve is automatically opened to depressurise the system. The chamber is intended to replace the lid of an existing vessel to convert a filter using filter aid to one using permanent filter elements. (author)

  13. Sub-micron filter

    Science.gov (United States)

    Tepper, Frederick [Sanford, FL; Kaledin, Leonid [Port Orange, FL

    2009-10-13

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

  14. Topical and working papers on heavy water accountability and safeguards

    International Nuclear Information System (INIS)

    This report contains the following papers: 1) Statement of IAEA concerning safeguarding of heavy water; 2) Preliminary Canadian Comments on IAEA document on heavy water safeguards; 3) Heavy water accountability 03.10.78; 4) Heavy water accountability 05.04.79

  15. Concentrations of the UV filter ethylhexyl methoxycinnamate in the aquatic compartment: a comparison of modelled concentrations for Swiss surface waters with empirical monitoring data.

    Science.gov (United States)

    Straub, Jürg Oliver

    2002-05-10

    UV filters in sunscreens and cosmetics protect the skin from damage through UV radiation. Many tonnes per year of UV filters are being used in Europe and will be present, at least seasonally, in detectable concentrations in surface waters similar to common pharmaceutically active substances. Predicted environmental concentrations (PECs) of ethylhexyl methoxycinnamate (EHMC; CAS 5466-77-3) were extrapolated for Switzerland, taking into consideration substance-specific environmental fate data and marketing estimates, by crude worst-case reckoning and by applying two environmental models (Mackay Level III; USES 3.0), both configured for Swiss hydrological and area data. By worst-case reckoning the summer PEC is 70.8-81.3 ng/l while for the remaining 8 months of the year the PEC is 13.1-15.1 ng/l. The Level III model results in concentrations of 2.4 ng/l during the summer and 0.44 ng/l during the rest of the year, while the USES 3.0 model gives an average PEC for the whole year of 7.6 ng/l. Pooling summer monitoring data (90 single analyses) from the River Rhine below Basel in the year 1997 (Water Protection Board of Basel) and from Lakes Zurich and Hüttner in 1998 (Poiger et al., in preparation) allowed a derivation of a probabilistic median concentration of 4.6 ng/l, a 95th-percentile concentration of 18.6 ng/l and a 99th-percentile concentration of 33.5 ng/l. The 6-fold range from the median value to the maximum calls for caution in interpreting published monitoring concentrations. Comparison of modelled PECs with realistic median concentrations shows that crude reckoning overestimates actual concentrations by a factor of about 10, probably through insufficient consideration of (further) degradation of EHMC in sewage works, surface waters, sediments or river banks. Both computer models, in contrast, are within the same order of magnitude as the actual summer concentrations. Based on the available data, both these environmental fate and distribution models give

  16. Characterization of filters and filtration process using X-ray computerized tomography

    International Nuclear Information System (INIS)

    Maschio, Celio; Arruda, Antonio Celso Fonseca de

    1999-01-01

    The objective of this work is to present the potential of X-Ray computerized tomography as a tool for internal characterization of filters used in the solid-liquid separation, mainly the water filters. Cartridge filters (for industrial and domestic applications) contaminated with glass beads were used. The scanning process was carried out both with and without contaminant in the filter to compare the attenuation coefficient of the clean filter and the contaminated filter. The images showed that is possible the mapping the internal structure of the filters and the distribution of the contaminant, permitting a local analysis, that is not possible through the standard tests used by the manufactures. These standard tests reveal only global characteristics of the filter media. The possibility of application for manufacturing process control was also shown, because the non invasive nature is a important advantage of the technique, which also permitted damage detection in filters submitted to severe operational conditions. (author)

  17. Filter arrays

    Science.gov (United States)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  18. Modeling the Performance of Biological Rapid Sand Filters Used to Remove Ammonium, Iron, and Manganese From Drinking Water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    activated carbon and are often used following ozonation to remove additional biodegradable organics created during ozonation. In Europe, biological filters are also used to remove ammonium and reduced forms of iron and manganese. These compounds can cause biological instability in the distribution system...... tracer, are performed during an operational cycle of a filter to examine how the filter flow changes with time. The data is used to validate a mathematical model that can both predict process performance and to gain an understanding of how dynamic conditions can influence filter performance....... The mathematical model developed is intended to assist in the design of new filters, set up of pilot plant studies, and as a tool to troubleshoot existing problems in full scale filters. Unlike previous models, the model developed accounts for the effects of particle/precipitate accumulation and its effects...

  19. Filters in nuclear facilities

    International Nuclear Information System (INIS)

    Berg, K.H.; Wilhelm, J.G.

    1985-01-01

    The topics of the nine papers given include the behavior of HEPA filters during exposure to air flows of high humidity as well as of high differential pressure, the development of steel-fiber filters suitable for extreme operating conditions, and the occurrence of various radioactive iodine species in the exhaust air from boiling water reactors. In an introductory presentation the German view of the performance requirements to be met by filters in nuclear facilities as well as the present status of filter quality assurance are discussed. (orig.) [de

  20. Effect of Fiber Volume Fraction and Water Absorption toward Bending Strength of Coconut Filters/ Polyester Composite

    Directory of Open Access Journals (Sweden)

    I Putu Lokantara

    2012-11-01

    Full Text Available The variation of fibre volume and the duration of water soaking take influence on the mechanical properties of composite. This research aim is to know the influence of fraction volume fibre and soaking duration on the mineral watertoward the tensile strength and flexural of polyester-coconut-tapis composite. This research used coconut-tapis fibre which is cut 1 cm in length with 0%, 5%, 7,5%, and 10% fiber volume fraction, unsaturated-polyester (UPRs matrix resin type Yucalac 157 BQTN-EX, and MEKPO hardener. The flexure specimen are made by press hand lay-up method and cut according ASTM D790-03 for the flexure test. The result of flexure test shows that the duration of soaking and the fiber volume fraction give a significant effect on the flexural strength of composite. The highest strength are reached by composite with 10% fibre volume on 48 hour soaking time equal to 41.994 MPa. The flexure modulus happenend shows increasing until 24 hour soaking time. The highest modulus are reached by composite with 10% fibre volume equal to 7.114 GPa while the lowest are reached by composite with 0% fibre volume equal to 3,023 GPa.

  1. Comparison of grey water treatment performance by a cascading sand filter and a constructed wetland.

    Science.gov (United States)

    Kadewa, W W; Le Corre, K; Pidou, M; Jeffrey, P J; Jefferson, B

    2010-01-01

    A novel unplanted vertical flow subsurface constructed wetland technology comprising three shallow beds (0.6 m length, 0.45 m width and 0.2 m depth) arranged in a cascading series and a standard single-pass Vertical Flow Planted Constructed Wetland (VFPCW, 6 m² and 0.7 m depth) were tested for grey water treatment. Particular focus was on meeting consent for published wastewater reuse parameters and removal of anionic surfactants. Treatment performance at two hydraulic loading rates (HLR) of 0.08, and 0.17 m³ m⁻² d⁻¹ were compared. Both technologies effectively removed more than 90% turbidity and more than 96% for organics with the prototype meeting the most stringent reuse standard of < 2 NTU and <10 mg/L. However, surfactant removal in the VFPCW was higher (76-85%) than in the prototype which only achieved more than 50% removal at higher loading rate. Generally, the prototype performed consistently better than the VFPCW except for surfactant removal. However, at higher loading rates, both systems did not meet the reuse standard of <1 mg L⁻¹ for anionic surfactants. This observation confirms that shallow beds provide a more oxidised environment leading to higher BOD₅ and COD removals. Presence of plants in the VFPCW led to higher anionic surfactant removal, through increased microbial and sorption processes.

  2. Selenite resistant rhizobacteria stimulate SeO(3) (2-) phytoextraction by Brassica juncea in bioaugmented water-filtering artificial beds.

    Science.gov (United States)

    Lampis, Silvia; Ferrari, Anita; Cunha-Queda, A Cristina F; Alvarenga, Paula; Di Gregorio, Simona; Vallini, Giovanni

    2009-09-01

    Selenium is a trace metalloid of global environmental concern. The boundary among its essentiality, deficiency, and toxicity is narrow and mainly depends on the chemical forms and concentrations in which this element occurs. Different plant species-including Brassica juncea-have been shown to play a significant role in Se removal from soil as well as water bodies. Furthermore, the interactions between such plants, showing natural capabilities of metal uptake and their rhizospheric microbial communities, might be exploited to increase both Se scavenging and vegetable biomass production in order to improve the whole phytoextraction efficiency. The aim of the present study was to evaluate the capability of selenite removal of B. juncea grown in hydroponic conditions on artificially spiked effluents. To optimize phytoextraction efficiency, interactions between B. juncea and rhizobacteria were designedly elicited. Firstly, B. juncea was grown on water-filtering agriperlite beds in the presence of three different selenite concentrations, namely, 0.2, 1.0, and 2.0 mM. Plant growth was measured after 3 and 6 weeks of incubation in order to establish the selenite concentration at which the best plant biomass production could be obtained. Afterwards, water-filtering agriperlite beds were inoculated either with a selenium-acclimated microbial community deriving from the rhizosphere of B. juncea grown, erstwhile, in a selenite-amended soil or with axenic cultures of two bacterial strains, vicelike Bacillus mycoides SeITE01 and Stenotrophomonas maltophilia SeITE02, previously isolated and described for their high resistance to selenite. These latter were seeded separately or as a dual consortium. Selenite was amended at a final concentration of 1.0 mM. Total Se content in plant tissues (both shoots and roots), plant biomass production, and persistence of bioaugmented microbial inocula during the experimental time were monitored. Moreover, parameters such as bioconcentration

  3. Household-based ceramic water filters for the prevention of diarrhea: a randomized, controlled trial of a pilot program in Colombia.

    Science.gov (United States)

    Clasen, Thomas; Garcia Parra, Gloria; Boisson, Sophie; Collin, Simon

    2005-10-01

    Household water treatment is increasingly recognized as an effective means of reducing the burden of diarrheal disease among low-income populations without access to safe water. Oxfam GB undertook a pilot project to explore the use of household-based ceramic water filters in three remote communities in Colombia. In a randomized, controlled trial over a period of six months, the filters were associated with a 75.3% reduction in arithmetic mean thermotolerant coliforms (TTCs) (P Health Organization limits for low risk (1-10 TTCs/100 mL), respectively, compared with 0.9% and 7.3% for control group samples. Overall, prevalence of diarrhea was 60% less among households using filters than among control households (odds ratio = 0.40, 95% confidence interval = 0.25, 0.63, P < 0.0001). However, the microbiologic performance and protective effect of the filters was not uniform throughout the study communities, suggesting the need to consider the circumstances of the particular setting before implementing this intervention.

  4. Improved virus removal in ceramic depth filters modified with MgO.

    Science.gov (United States)

    Michen, Benjamin; Fritsch, Johannes; Aneziris, Christos; Graule, Thomas

    2013-02-05

    Ceramic filters, working on the depth filtration principle, are known to improve drinking water quality by removing human pathogenic microorganisms from contaminated water. However, these microfilters show no sufficient barrier for viruses having diameters down to 20 nm. Recently, it was shown that the addition of positively charged materials, for example, iron oxyhydroxide, can improve virus removal by adsorption mechanisms. In this work, we modified a common ceramic filter based on diatomaceous earth by introducing a novel virus adsorbent material, magnesium oxyhydroxide, into the filter matrix. Such filters showed an improved removal of about 4-log in regard to bacteriophages MS2 and PhiX174. This is explained with the electrostatic enhanced adsorption approach that is the favorable adsorption of negatively charged viruses onto positively charged patches in an otherwise negatively charged filter matrix. Furthermore, we provide theoretical evidence applying calculations according to Derjaguin-Landau-Verwey-Overbeek theory to strengthen our experimental results. However, modified filters showed a significant variance in virus removal efficiency over the course of long-term filtration experiments with virus removal increasing with filter operation time (or filter aging). This is explained by transformational changes of MgO in the filter upon contact with water. It also demonstrates that filter history is of great concern when filters working on the adsorption principles are evaluated in regard to their retention performance as their surface characteristics may alter with use.

  5. Drinking Water in your Home

    Science.gov (United States)

    Many people choose to filter or test the drinking water that comes out of their tap or from their private well for a variety of reasons. And whether at home, at work or while traveling, many Americans drink bottled water.

  6. Functional lignocellulosic material for the remediation of copper(II) ions from water: Towards the design of a wood filter.

    Science.gov (United States)

    Vitas, Selin; Keplinger, Tobias; Reichholf, Nico; Figi, Renato; Cabane, Etienne

    2018-05-09

    In this study, the chemical modification of bulk beech wood is described along with its utilization as biosorbent for the remediation of copper from water. The material was prepared by esterification using anhydrides, and reaction conditions were optimized to propose a greener process, in particular by reducing the amount of solvent. This modification yields a lignocellulosic material whose native structure is preserved, with an increased amount of carboxylic groups (up to 3 mmol/g). We demonstrate that the material can remove up to 95% of copper from low concentration solutions (100- 500 ppm). The adsorption efficiency decreases with concentrated copper solutions, and we show that a limited number of -COOH groups participate in copper binding (ca. 0.1 Cu/-COOH). This result suggests a limited accessibility of -COOH groups in the wood scaffold. This was demonstrated by the characterization of -COOH and copper distributions inside wood. Raman and EDX imaging confirmed that most -COOH groups are located inside the wood cell walls, thereby limiting interactions with copper. According to this study, critical limitations of bulk wood as a biosorbent were identified, and the results will be used to improve the material and design an efficient wood filter for heavy metal remediation. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Determination of pesticides and pesticide degradates in filtered water by direct aqueous-injection liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Sandstrom, Mark W.; Kanagy, Leslie K.; Anderson, Cyrissa A.; Kanagy, Christopher J.

    2016-01-11

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for determination of 229 pesticides compounds (113 pesticides and 116 pesticide degradates) in filtered water samples from stream and groundwater sites. The pesticides represent a broad range of chemical classes and were selected based on criteria such as current-use intensity, probability of occurrence in streams and groundwater, and toxicity to humans or aquatic organisms. More than half of the analytes are pesticide degradates. The method involves direct injection of a 100-microliter (μL) sample onto the LC-MS/MS without any sample preparation other than filtration. Samples are analyzed with two injections, one in electrospray ionization (ESI) positive mode and one in ESI negative mode, using dynamic multiple reaction monitoring (MRM) conditions, with two MRM transitions for each analyte. The LC-MS/MS instrument parameters were optimized for highest sensitivity for the most analytes. This report describes the analytical method and presents characteristics of the method validation including bias and variability, detection levels, and holding-time studies.

  8. Comparison between Removal Efficiency of Slag, zeolite, and Conventional media in slow sand Filter for Removal of Lead and Cadmium from Water Resources

    Directory of Open Access Journals (Sweden)

    A Ebrahimi

    2016-03-01

    Full Text Available Introduction: Heavy metals owing to their health hazards and high toxicity in low concentration for human and environment have very concern and attention. Slow sand filter is one of the simple and cost-effective for removal of these pollutants. In this method, media play an important role for removal of pollutant. Therefore, the aim of this study was investigation of different media like slag, zeolite, and conventional media in slow sand filter for removal of lead and cadmium. Methods: In this research there are three beds filter include typical filter bed, slag and zeolite that used in pilot plant for investigation of lead and cadmium removal at three concentration of 0.1T 1 and 10 ppm. Each of filters has an internal diameter of 8 cm and a height of 120 cm with Plexiglas, which have a continuous flow operation. Results: The removal efficiency of turbidity by three typical filter bed, slag, and zeolite with initial turbidity of 13 NTU was 46%, 77%, and 89% respectively. Removal efficiency of lead without turbidity was 70.3%, 79%, and 59.8% respectively for 0.1 ppm lead. For 1 ppm, concentration of lead removal efficiency was 51.8%, 52.7% and 52.6% respectively and for 10 ppm it was 53.4%, 57.8%, and 59.8% respectively. Cadmium removal for these media was 23.4%, 37.5%, and 59.4% respectively at 0.1 ppm cadmium. At 1 ppm of cadmium concentration, it was 37.9%, 45% and 41.3% respectively and at 10 ppm concentration of cadmium it was 68.3%, 68.6% and 67% respectively. Conclusion: Slag and zeolite beds are more efficiently than the conventional sand beds in the slow sand filter, so it can be used instead of the usual sand for removing lead and cadmium from resources water.

  9. Bioaugmentation of rapid sand filters by microbiome priming with a nitrifying consortium will optimize production of drinking water from groundwater

    DEFF Research Database (Denmark)

    Albers, Christian Nyrop; Ellegaard-Jensen, Lea; Hansen, Lars Hestbjerg

    2018-01-01

    . It is shown that nitrifying communities could be enriched by microbiomes from well-functioning rapid sand filters in waterworks and that the enriched nitrifying consortium could be used to inoculate fresh filters, significantly shortening the time taken for the nitrification process to start. The key...

  10. Peatlands as Filters for Polluted Mine Water?—A Case Study from an Uranium-Contaminated Karst System in South Africa—Part II: Examples from Literature and a Conceptual Filter Model

    Directory of Open Access Journals (Sweden)

    Frank Winde

    2011-03-01

    Full Text Available As the second part of a series of four, this paper reviews a number of case studies of natural uranium attenuation in peat, as well as underlying chemical mechanisms reported in literature. Based on this review, a generic, conceptual, model for peat to act as filter for dissolved uranium (U is developed for guiding subsequent field investigations. The model consists of a chemical and an hydraulic component which is derived largely from data reported in literature as well as from limited field observations. For the chemical model component 10 different processes, each controlled by factors relating to water chemistry, have been identified to govern the attenuation of U in peat via a net balance of immobilization and remobilization. For the hydraulic aspect of the filter model, five different principal modes of U polluted water coming in contact with peat are discussed, focusing on the associated peat-water contact time as a crucial parameter controlling chemical U attenuation. Moreover, links between the two model components are discussed and, based on the integrated conceptual model, possible effects of natural and anthropogenic events on U attenuation in peatlands are outlined. Guided by the model, various site-specific field and laboratory investigations are finally designed to verify how far the identified generic factors and processes are indeed applicable to the Gerhard Minnebron Peatland.

  11. Multilevel ensemble Kalman filter

    KAUST Repository

    Chernov, Alexey; Hoel, Haakon; Law, Kody; Nobile, Fabio; Tempone, Raul

    2016-01-01

    This work embeds a multilevel Monte Carlo (MLMC) sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF). In terms of computational cost vs. approximation error the asymptotic performance of the multilevel ensemble Kalman filter (MLEnKF) is superior to the EnKF s.

  12. Multilevel ensemble Kalman filter

    KAUST Repository

    Chernov, Alexey

    2016-01-06

    This work embeds a multilevel Monte Carlo (MLMC) sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF). In terms of computational cost vs. approximation error the asymptotic performance of the multilevel ensemble Kalman filter (MLEnKF) is superior to the EnKF s.

  13. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 2: model coupling, application, factor importance, and uncertainty

    Science.gov (United States)

    Lauvernet, Claire; Muñoz-Carpena, Rafael

    2018-01-01

    Vegetative filter strips are often used for protecting surface waters from pollution transferred by surface runoff in agricultural watersheds. In Europe, they are often prescribed along the stream banks, where a seasonal shallow water table (WT) could decrease the buffer zone efficiency. In spite of this potentially important effect, there are no systematic experimental or theoretical studies on the effect of this soil boundary condition on the VFS efficiency. In the companion paper (Muñoz-Carpena et al., 2018), we developed a physically based numerical algorithm (SWINGO) that allows the representation of soil infiltration with a shallow water table. Here we present the dynamic coupling of SWINGO with VFSMOD, an overland flow and transport mathematical model to study the WT influence on VFS efficiency in terms of reductions of overland flow, sediment, and pesticide transport. This new version of VFSMOD was applied to two contrasted benchmark field studies in France (sandy-loam soil in a Mediterranean semicontinental climate, and silty clay in a temperate oceanic climate), where limited testing of the model with field data on one of the sites showed promising results. The application showed that for the conditions of the studies, VFS efficiency decreases markedly when the water table is 0 to 1.5 m from the surface. In order to evaluate the relative importance of WT among other input factors controlling VFS efficiency, global sensitivity and uncertainty analysis (GSA) was applied on the benchmark studies. The most important factors found for VFS overland flow reduction were saturated hydraulic conductivity and WT depth, added to sediment characteristics and VFS dimensions for sediment and pesticide reductions. The relative importance of WT varied as a function of soil type (most important at the silty-clay soil) and hydraulic loading (rainfall + incoming runoff) at each site. The presence of WT introduced more complex responses dominated by strong interactions in

  14. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 2: model coupling, application, factor importance, and uncertainty

    Directory of Open Access Journals (Sweden)

    C. Lauvernet

    2018-01-01

    Full Text Available Vegetative filter strips are often used for protecting surface waters from pollution transferred by surface runoff in agricultural watersheds. In Europe, they are often prescribed along the stream banks, where a seasonal shallow water table (WT could decrease the buffer zone efficiency. In spite of this potentially important effect, there are no systematic experimental or theoretical studies on the effect of this soil boundary condition on the VFS efficiency. In the companion paper (Muñoz-Carpena et al., 2018, we developed a physically based numerical algorithm (SWINGO that allows the representation of soil infiltration with a shallow water table. Here we present the dynamic coupling of SWINGO with VFSMOD, an overland flow and transport mathematical model to study the WT influence on VFS efficiency in terms of reductions of overland flow, sediment, and pesticide transport. This new version of VFSMOD was applied to two contrasted benchmark field studies in France (sandy-loam soil in a Mediterranean semicontinental climate, and silty clay in a temperate oceanic climate, where limited testing of the model with field data on one of the sites showed promising results. The application showed that for the conditions of the studies, VFS efficiency decreases markedly when the water table is 0 to 1.5 m from the surface. In order to evaluate the relative importance of WT among other input factors controlling VFS efficiency, global sensitivity and uncertainty analysis (GSA was applied on the benchmark studies. The most important factors found for VFS overland flow reduction were saturated hydraulic conductivity and WT depth, added to sediment characteristics and VFS dimensions for sediment and pesticide reductions. The relative importance of WT varied as a function of soil type (most important at the silty-clay soil and hydraulic loading (rainfall + incoming runoff at each site. The presence of WT introduced more complex responses dominated by strong

  15. A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

    Science.gov (United States)

    Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

    2014-01-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15–0.30) for the filter arm and 0.27 (95% CI = 0.22–0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59–0.86). PMID:24865680

  16. Phototransformation of the sunlight filter benzophenone-3 (2-hydroxy-4-methoxybenzophenone) under conditions relevant to surface waters

    International Nuclear Information System (INIS)

    Vione, Davide; Caringella, Rosalinda; De Laurentiis, Elisa; Pazzi, Marco; Minero, Claudio

    2013-01-01

    The UV filter benzophenone-3 (BP3) has UV photolysis quantum yield Φ BP3 = (3.1 ± 0.3) · 10 −5 and the following second-order reaction rate constants: with • OH, k BP3, • OH = (2.0 ± 0.4) · 10 10 M −1 s −1 ; with the triplet states of chromophoric dissolved organic matter ( 3 CDOM*), k BP3, 3 CDOM* = (1.1 ± 0.1) · 10 9 M −1 s −1 ; with 1 O 2 , k BP3, 1 O 2 = (2.0 ± 0.1) · 10 5 M −1 s −1 , and with CO 3 −• , k BP3,CO 3 −• 7 M −1 s −1 . These data allow the modelling of BP3 photochemical transformation, which helps filling the knowledge gap about the environmental persistence of this compound. Under typical surface-water conditions, direct photolysis and reactions with • OH and 3 CDOM* would be the main processes of BP3 phototransformation. Reaction with • OH would prevail at low DOC, direct photolysis at intermediate DOC (around 5 mg C L −1 ), and reaction with 3 CDOM* at high DOC. If the reaction rate constant with CO 3 −• is near the upper limit of experimental measures (5 · 10 7 M −1 s −1 ), the CO 3 −• degradation process could be somewhat important for DOC −1 . The predicted half-life time of BP3 in surface waters under summertime conditions would be of some weeks, and it would increase with increasing depth and DOC. BP3 transformation intermediates were detected upon reaction with • OH. Two methylated derivatives were tentatively identified, and they were probably produced by reaction between BP3 and fragments arising from photodegradation. The other intermediates were benzoic acid (maximum concentration ∼ 10% of initial BP3) and benzaldehyde (1%). Highlights: • Benzophenone-3 is mainly photodegraded by direct photolysis, • OH and 3 CDOM*. • Two methylated isomers, benzaldehyde and benzoic acid detected as intermediates. • Phototransformation would be faster in shallow and DOM-poor water. • Half-life times of benzophenone-3 are in the range of weeks to a couple of months.

  17. Truncation correction for oblique filtering lines

    International Nuclear Information System (INIS)

    Hoppe, Stefan; Hornegger, Joachim; Lauritsch, Guenter; Dennerlein, Frank; Noo, Frederic

    2008-01-01

    State-of-the-art filtered backprojection (FBP) algorithms often define the filtering operation to be performed along oblique filtering lines in the detector. A limited scan field of view leads to the truncation of those filtering lines, which causes artifacts in the final reconstructed volume. In contrast to the case where filtering is performed solely along the detector rows, no methods are available for the case of oblique filtering lines. In this work, the authors present two novel truncation correction methods which effectively handle data truncation in this case. Method 1 (basic approach) handles data truncation in two successive preprocessing steps by applying a hybrid data extrapolation method, which is a combination of a water cylinder extrapolation and a Gaussian extrapolation. It is independent of any specific reconstruction algorithm. Method 2 (kink approach) uses similar concepts for data extrapolation as the basic approach but needs to be integrated into the reconstruction algorithm. Experiments are presented from simulated data of the FORBILD head phantom, acquired along a partial-circle-plus-arc trajectory. The theoretically exact M-line algorithm is used for reconstruction. Although the discussion is focused on theoretically exact algorithms, the proposed truncation correction methods can be applied to any FBP algorithm that exposes oblique filtering lines.

  18. Rectifier Filters

    Directory of Open Access Journals (Sweden)

    Y. A. Bladyko

    2010-01-01

    Full Text Available The paper contains definition of a smoothing factor which is suitable for any rectifier filter. The formulae of complex smoothing factors have been developed for simple and complex passive filters. The paper shows conditions for application of calculation formulae and filters

  19. "Wetlands: Water Living Filters?",

    OpenAIRE

    Dordio, Ana; Palace, A. J.; Pinto, Ana Paula

    2008-01-01

    Human societies have indirectly used natural wetlands as wastewater discharge sites for many centuries. Observations of the wastewater depuration capacity of natural wetlands have led to a greater understanding of the potential of these ecosystems for pollutant assimilation and have stimulated the development of artificial wetlands systems for treatment of wastewaters from a variety of sources. Constructed wetlands, in contrast to natural wetlands, are human-made systems that are designed, bu...

  20. Fabrication of TiO2/EP super-hydrophobic thin film on filter paper surface.

    Science.gov (United States)

    Gao, Zhengxin; Zhai, Xianglin; Liu, Feng; Zhang, Ming; Zang, Deli; Wang, Chengyu

    2015-09-05

    A composite filter paper with super-hydrophobicity was obtained by adhering micro/nano structure of amorphous titanium dioxide on the filter paper surface with modifying low surface energy material. By virtue of the coupling agent, which plays an important part in bonding amorphous titanium dioxide and epoxy resin, the structure of super-hydrophobic thin film on the filter paper surface is extremely stable. The microstructure of super-hydrophobic filter paper was characterized by scanning electron microscopy (SEM), the images showed that the as-prepared filter paper was covered with uniform amorphous titanium dioxide particles, generating a roughness structure on the filter paper surface. The super-hydrophobic performance of the filter paper was characterized by water contact angle measurements. The observations showed that the wettability of filter paper samples transformed from super-hydrophilicity to super-hydrophobicity with the water contact angle of 153 ± 1°. Some experiments were also designed to test the effect of water-oil separation and UV-resistant by the super-hydrophobic filter paper. The prepared super-hydrophobic filter paper worked efficiently and simply in water-oil separation as well as enduringly in anti-UV property after the experiments. This method offers an opportunity to the practical applications of the super-hydrophobic filter paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Water-filtered infrared-A (wIRA overcomes swallowing disorders and hypersalivation – a case report

    Directory of Open Access Journals (Sweden)

    Hoffmann, Gerd

    2017-08-01

    Full Text Available Case description: A patient with a Barrett oesophageal carcinoma and a resection of the oesophagus with gastric pull-up developed swallowing disorders 6 years and 2 months after the operation. Within 1 year and 7 months two recurrences of the tumor at the anastomosis were found and treated with combined chemoradiotherapy or chemotherapy respectively. 7 years and 9 months after the operation local tumor masses and destruction were present with no ability to orally drink or eat (full feeding by jejunal PEG tube: quality of life was poor, as saliva and mucus were very viscous (pulling filaments and could not be swallowed and had to be spat out throughout the day and night resulting in short periods of sleep (awaking from the necessity to spit out. In total the situation was interpreted more as a problem related to a feeling of choking (with food or fluid in the sense of a functional dysphagia rather than as a swallowing disorder from a structural stenosis. At that time acetylcysteine (2 times 200 mg per day, given via the PEG tube and irradiation with water-filtered infrared-A (wIRA, a special form of heat radiation, of the ventral part of the neck and the thorax were added to the therapy. Within 1 day with acetylcysteine saliva and mucus became less viscous. Within 2 days with wIRA (one day with 4 to 5 hours with irradiation with wIRA at home salivation decreased markedly and quality of life clearly improved: For the first time the patient slept without interruption and without the need for sleep-inducing medication. After 5 days with wIRA the patient could eat his first soft dumpling although drinking of fluids was still not possible. After 2½ weeks with wIRA the patient could eat his first minced schnitzel (escalope. Following the commencement of wIRA (with typically approximately 90–150 minutes irradiation with wIRA per day the patient had 8 months with good quality of life with only small amounts of liquid saliva and mucus and without the

  2. Work Plan for a Water Quality Model of Florida Bay

    National Research Council Canada - National Science Library

    Dortch, Mark

    1997-01-01

    .... The model is required to address issues pertaining to nutrient inputs and associated impacts on water quality and sea grass, particularly as related to changes in freshwater inflows from south...

  3. Investigation of the effects of slow-release fertilizer and struvite in biodegradation in filter drains and potential application of treated water in irrigation of road verges.

    Science.gov (United States)

    Theophilus, Stephen C; Mbanaso, Fredrick U; Nnadi, Ernest O; Onyedeke, Kingsley T

    2017-11-14

    Filter drains are usually laid along the margins of highways. Highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Therefore, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanisms in filter drains, but it is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate the impact of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. Filter drain models incorporated with geotextile were challenged with cumulative oil loading of 178 mg/m 2 /week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13 mm/week. Nutrients and street dust were applied at one-off rate of 17 g/m 2 and 1.55 g/rig to provide nutrient enhancement and simulate field conditions respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using nutrient agar, Rose Bengal Agar media and CO2 evolution. EC, pH, heavy metals, TPH, elemental analysis and SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid for trees and flowers planted on road verges. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with differences in type of nutrient applied. Also, it was observed that incorporation of geotextiles in filter drains improved pollution retention efficiency and there is a potential opportunity for utilization of struvite in SuDS systems as sustainable nutrient source.

  4. Application of Iranian natural zeolite and blast furnace slag as slow sand filters media for water softening

    Directory of Open Access Journals (Sweden)

    Ali Abdolahnejad

    2014-01-01

    Conclusions: It is concluded from this study that modified filter media, SMF and ZMF, are very good options for total hardness and turbidity removals in communities that have some problem with this parameter.

  5. Ceramic water filters impregnated with silver nanoparticles as a point-of-use water-treatment intervention for HIV-positive individuals in Limpopo Province, South Africa: a pilot study of technological performance and human health benefits.

    Science.gov (United States)

    Abebe, Lydia Shawel; Smith, James A; Narkiewicz, Sophia; Oyanedel-Craver, Vinka; Conaway, Mark; Singo, Alukhethi; Amidou, Samie; Mojapelo, Paul; Brant, Julia; Dillingham, Rebecca

    2014-06-01

    Waterborne pathogens present a significant threat to people living with the human immunodeficiency virus (PLWH). This study presents a randomized, controlled trial that evaluates whether a household-level ceramic water filter (CWF) intervention can improve drinking water quality and decrease days of diarrhea in PLWH in rural South Africa. Seventy-four participants were randomized in an intervention group with CWFs and a control group without filters. Participants in the CWF arm received CWFs impregnated with silver nanoparticles and associated safe-storage containers. Water and stool samples were collected at baseline and 12 months. Diarrhea incidence was self-reported weekly for 12 months. The average diarrhea rate in the control group was 0.064 days/week compared to 0.015 days/week in the intervention group (p water and decrease days of diarrhea for PLWH in rural South Africa.

  6. How the Drinking Water State Revolving Fund Works

    Science.gov (United States)

    The DWSRF was established by the 1996 amendments to the Safe Drinking Water Act (SDWA) as a financial assistance program for systems and states to achieve the health protection objectives of the law, 42 U.S.C. §300j-12

  7. Development of regulations for water care works and process ...

    African Journals Online (AJOL)

    driniev

    In terms of the South African Qualifications Authority Act of 1995 (SAQA) and the ... persons must be trained and assessed using unit standards generated for each particular sector. ... works are common, giving rise to major pollution incidents.

  8. Phototransformation of the sunlight filter benzophenone-3 (2-hydroxy-4-methoxybenzophenone) under conditions relevant to surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Vione, Davide, E-mail: davide.vione@unito.it [Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino (Italy); Università degli Studi di Torino, Centro Interdipartimentale NatRisk, Via L. Da Vinci 44, 10095 Grugliasco (Italy); Caringella, Rosalinda; De Laurentiis, Elisa; Pazzi, Marco; Minero, Claudio [Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino (Italy)

    2013-10-01

    The UV filter benzophenone-3 (BP3) has UV photolysis quantum yield Φ{sub BP3} = (3.1 ± 0.3) · 10{sup −5} and the following second-order reaction rate constants: with {sup •} OH, k{sub BP3,{sup •}} {sub OH} = (2.0 ± 0.4) · 10{sup 10} M{sup −1} s{sup −1}; with the triplet states of chromophoric dissolved organic matter ({sup 3}CDOM*), k{sub BP3,{sup 3}CDOM*} = (1.1 ± 0.1) · 10{sup 9} M{sup −1} s{sup −1}; with {sup 1}O{sub 2}, k{sub BP3,{sup 1}O{sub 2}} = (2.0 ± 0.1) · 10{sup 5} M{sup −1} s{sup −1}, and with CO{sub 3}{sup −•} , k{sub BP3,CO{sub 3{sup −}{sup •}}} < 5 · 10{sup 7} M{sup −1} s{sup −1}. These data allow the modelling of BP3 photochemical transformation, which helps filling the knowledge gap about the environmental persistence of this compound. Under typical surface-water conditions, direct photolysis and reactions with {sup •} OH and {sup 3}CDOM* would be the main processes of BP3 phototransformation. Reaction with {sup •} OH would prevail at low DOC, direct photolysis at intermediate DOC (around 5 mg C L{sup −1}), and reaction with {sup 3}CDOM* at high DOC. If the reaction rate constant with CO{sub 3}{sup −•} is near the upper limit of experimental measures (5 · 10{sup 7} M{sup −1} s{sup −1}), the CO{sub 3}{sup −•} degradation process could be somewhat important for DOC < 1 mg C L{sup −1}. The predicted half-life time of BP3 in surface waters under summertime conditions would be of some weeks, and it would increase with increasing depth and DOC. BP3 transformation intermediates were detected upon reaction with {sup •} OH. Two methylated derivatives were tentatively identified, and they were probably produced by reaction between BP3 and fragments arising from photodegradation. The other intermediates were benzoic acid (maximum concentration ∼ 10% of initial BP3) and benzaldehyde (1%). Highlights: • Benzophenone-3 is mainly photodegraded by direct photolysis, {sup •} OH and {sup 3}CDOM*.

  9. Fremont Tree-Well Filter

    Science.gov (United States)

    Information about the SFBWQP Fremont Tree-Well Filter Spine project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  10. [On bacterial aftergrowth in drinking and industrial water. II. Apparative and processing influence upon the growth and the possibility of disinfection of ion exchange resin filter systems (author's transl)].

    Science.gov (United States)

    Schubert, R H

    1975-12-01

    The comparative examination of numerous ion exchange resin filter systems for discontinuous water softening on the market revealed that apparative and processing characteristics are of great influence upon the aftergrowth of bacteria in the water of ion exchange resin systems. Within the examination it was taken into consideration that on the end-delivery-tube of the water pipe with regard to the colony count the conditions were more unfavourable during the long standstill over a weekend (table 1) than during the week (table2). The less favourable conditions have therefore been examined separately. The work has been divided in six test series. In the first one 5 ion exchange resin systems the types A-E are simultaneously tested with regard to the colony count in the water at the inflow to the apparatus and after the passage of it; regeneration twice a week with sodium chloride. The data ascertained in the course of several weeks (without first data on mondays) and the separated mondays data are examined according to logarithmic transformation with the assistance of variance analysis and the Newman Keuls-test for differences. The results show (tab. 4 and 5) that apparative parameters and such relevant to the technical process (tab. 3) have an influence upon the bacterial after growth of the water. The most favourable ion exchange resin filter is type E because it shows more favourable values than all other systems and the tapwater. In the second test serie the systems A-E have been regenerated with 1% Chloramin T containing sodium chloride. The results show again the type E as the statistically significant most favourable system in comparison with the others and the tapwater. In the third test serie it has been examined whether the long period of standstill of the brine in the resin bed which has probably been responsible for the good results of the type E would lead to values just as favourable if transferred to another type of apparatus. ...

  11. Study design of a cluster-randomized controlled trial to evaluate a large-scale distribution of cook stoves and water filters in Western Province, Rwanda.

    Science.gov (United States)

    Nagel, Corey L; Kirby, Miles A; Zambrano, Laura D; Rosa, Ghislane; Barstow, Christina K; Thomas, Evan A; Clasen, Thomas F

    2016-12-15

    In Rwanda, pneumonia and diarrhea are the first and second leading causes of death, respectively, among children under five. Household air pollution (HAP) resultant from cooking indoors with biomass fuels on traditional stoves is a significant risk factor for pneumonia, while consumption of contaminated drinking water is a primary cause of diarrheal disease. To date, there have been no large-scale effectiveness trials of programmatic efforts to provide either improved cookstoves or household water filters at scale in a low-income country. In this paper we describe the design of a cluster-randomized trial to evaluate the impact of a national-level program to distribute and promote the use of improved cookstoves and advanced water filters to the poorest quarter of households in Rwanda. We randomly allocated 72 sectors (administratively defined units) in Western Province to the intervention, with the remaining 24 sectors in the province serving as controls. In the intervention sectors, roughly 100,000 households received improved cookstoves and household water filters through a government-sponsored program targeting the poorest quarter of households nationally. The primary outcome measures are the incidence of acute respiratory infection (ARI) and diarrhea among children under five years of age. Over a one-year surveillance period, all cases of acute respiratory infection (ARI) and diarrhea identified by health workers in the study area will be extracted from records maintained at health facilities and by community health workers (CHW). In addition, we are conducting intensive, longitudinal data collection among a random sample of households in the study area for in-depth assessment of coverage, use, environmental exposures, and additional health measures. Although previous research has examined the impact of providing household water treatment and improved cookstoves on child health, there have been no studies of national-level programs to deliver these interventions

  12. Determination of human-use pharmaceuticals in filtered water by direct aqueous injection: high-performance liquid chromatography/tandem mass spectrometry

    Science.gov (United States)

    Furlong, Edward T.; Noriega, Mary C.; Kanagy, Christopher J.; Kanagy, Leslie K.; Coffey, Laura J.; Burkhardt, Mark R.

    2014-01-01

    This report describes a method for the determination of 110 human-use pharmaceuticals using a 100-microliter aliquot of a filtered water sample directly injected into a high-performance liquid chromatograph coupled to a triple-quadrupole tandem mass spectrometer using an electrospray ionization source operated in the positive ion mode. The pharmaceuticals were separated by using a reversed-phase gradient of formic acid/ammonium formate-modified water and methanol. Multiple reaction monitoring of two fragmentations of the protonated molecular ion of each pharmaceutical to two unique product ions was used to identify each pharmaceutical qualitatively. The primary multiple reaction monitoring precursor-product ion transition was quantified for each pharmaceutical relative to the primary multiple reaction monitoring precursor-product transition of one of 19 isotope-dilution standard pharmaceuticals or the pesticide atrazine, using an exact stable isotope analogue where possible. Each isotope-dilution standard was selected, when possible, for its chemical similarity to the unlabeled pharmaceutical of interest, and added to the sample after filtration but prior to analysis. Method performance for each pharmaceutical was determined for reagent water, groundwater, treated drinking water, surface water, treated wastewater effluent, and wastewater influent sample matrixes that this method will likely be applied to. Each matrix was evaluated in order of increasing complexity to demonstrate (1) the sensitivity of the method in different water matrixes and (2) the effect of sample matrix, particularly matrix enhancement or suppression of the precursor ion signal, on the quantitative determination of pharmaceutical concentrations. Recovery of water samples spiked (fortified) with the suite of pharmaceuticals determined by this method typically was greater than 90 percent in reagent water, groundwater, drinking water, and surface water. Correction for ambient environmental

  13. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  14. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Tugwell, Peter; Boers, Maarten; D'Agostino, Maria-Antonietta

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter requires that criteria be met to demonstrate that the outcome instrument meets...... the criteria for content, face, and construct validity. METHODS: Discussion groups critically reviewed a variety of ways in which case studies of current OMERACT Working Groups complied with the Truth component of the Filter and what issues remained to be resolved. RESULTS: The case studies showed...... that there is broad agreement on criteria for meeting the Truth criteria through demonstration of content, face, and construct validity; however, several issues were identified that the Filter Working Group will need to address. CONCLUSION: These issues will require resolution to reach consensus on how Truth...

  15. High flow ceramic pot filters.

    Science.gov (United States)

    van Halem, D; van der Laan, H; Soppe, A I A; Heijman, S G J

    2017-11-01

    Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6-19 L h -1 ), but initial LRVs for E. coli of high flow filters was slightly lower than for regular ceramic pot filters. This disadvantage was, however, only temporarily as the clogging in high flow filters had a positive effect on the LRV for E. coli (from below 1 to 2-3 after clogging). Therefore, it can be carefully concluded that regular ceramic pot filters perform better initially, but after clogging, the high flow filters have a higher flow rate as well as a higher LRV for E. coli. To improve the initial performance of new high flow filters, it is recommended to further utilize residence time of the water in the receptacle, since additional E. coli inactivation was observed during overnight storage. Although a relationship was observed between flow rate and LRV of MS2 bacteriophages, both regular and high flow filters were unable to reach over 2 LRV. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Production of porous filter elements from PEUAPM nanocomposites and silver nanoparticles

    International Nuclear Information System (INIS)

    Bizzo, M.A.; Hui, W.S.

    2014-01-01

    The production of filter elements for water based in polymers is widespread in the market, but has an undesirable characteristic: they are not efficient and able to retain or eliminate microorganisms at all times. This paper proposes to produce nanocomposite filters with biocidal properties composed of ultra-high molecular weight polyethylene(UHMWPE) and silver nanoparticles, the UHMWPE is responsible for the uniform porous structure of the filters and the silver nanoparticles incorporated on the polymer are responsible for the biocide action. Particulate polymer that presents a different particle size curve was used for sintering the filters. Samples of filter elements obtained in this work were characterized by the techniques of X-ray diffraction, scanning electron microscopy and EDS microanalysis. The results indicated a porosity of approximately 49% in the filter, and the formation of the nanocomposite. key-words: nanocomposites, silver, UHMWPE, filter elements. (author)

  17. Shodagor Family Strategies : Balancing Work and Family on the Water.

    Science.gov (United States)

    Starkweather, Kathrine E

    2017-06-01

    The Shodagor of Matlab, Bangladesh, are a seminomadic community of people who live and work on small wooden boats, within the extensive system of rivers and canals that traverse the country. This unique ecology places particular constraints on family and economic life and leads to Shodagor parents employing one of four distinct strategies to balance childcare and provisioning needs. The purpose of this paper is to understand the conditions that lead a family to choose one strategy over another by testing predictions about socioecological factors that impact the sexual division of labor, including a family's stage in the domestic cycle, aspects of the local ecology, and the availability of alloparents. Results show that although each factor has an impact on the division of labor individually, a confluence of these factors best explains within-group, between-family differences in how mothers and fathers divide subsistence and childcare labor. These factors also interact in particular ways for Shodagor families, and it appears that families choose their economic strategies based on the constellation of constraints that they face. The results of these analyses have implications for theory regarding the sexual division of labor across cultures and inform how Shodagor family economic and parenting strategies should be contextualized in future studies.

  18. Comparative study of cost-benefit integrated system of water spary with industrial ventilation and bag filters in a minerals processing company

    Directory of Open Access Journals (Sweden)

    Morteza Babaei

    2016-06-01

    Full Text Available Introduction: Control of fugitative dust from mining process and application of an appropriate and economical system for dust collecting is essential. The goal of this study was cost-benefit analysis of an integrated systems and compare to bag filter in a crushing plant of a mining company. Methods: A local exhaust ventilation system for capture of emitted particlees, a water spray for dust suppresion at sources and parallel Stairmand model cyclones as dust colletor were designed and installed based on the standards and guidelines. Then, efficiency of wetting and industrial ventilation system for control of ambient dust personal exposure and environmental emission have evaluated as integrated and alone. Finally, cost-benefit analysis of this system was compared to bag filter. Results: The efficiency of this system for control personal exposure repairable particles and emitted dust to ambient air was 87% and 95% for plant 1 and 88% and 95% for plant 2, respectively. The concentration of emitted emitted dust from stack to environment were 121.28 mg/m3 and 112/68 mg/m3 for plant 1 and 2, respectively. The capital, operational and maintence costs of this option was 217 and 0.992 billion rials lower than bag filter. Also, annuall collected dust by cyclones was worth 518 million rial. Conclusion: According to results, integrated system had a significant impact on emitted dust in workplace and environment. The economical analysis domonstrated 73% and 80% savings in capital and operational costs compared to bag filter. Total costs of implented project will be compensated at 220 day with recovered dusts, therefore, in the same condition, it can be suggested as the favourable and economical solution.

  19. Filter systems

    International Nuclear Information System (INIS)

    Vanin, V.R.

    1990-01-01

    The multidetector systems for high resolution gamma spectroscopy are presented. The observable parameters for identifying nuclides produced simultaneously in the reaction are analysed discussing the efficiency of filter systems. (M.C.K.)

  20. Science in and out of the classroom: A look at Water Resource at Gammams Water Care Works, Namibia

    Science.gov (United States)

    Iileka-Shinavene, Leena

    2016-04-01

    Primary school pupils in Van Rhyn School in Namibia are taught Natural Sciences from grade 4 at the age of 9. The curriculum is mainly theory/classroom based and natural science is taught through theory and various practical activities. However occasionally teachers have opportunities to supplement the pupils' learning experience through outdoor activities such as excursions to museums, municipal works and science fairs. Apart from enhancing the learning experience and improving understanding, such activities make the Natural science subject more interesting subject to learners. Water, a scarce/limited resource in Namibia, is one of the topics we cover in Natural sciences. Sustainable management of water is one of the top priorities of the government, which through various initiatives including the National Development Plan supports innovative ideas and technologies to reclaim water from sewage, recycling of industry and mining water and use semi-purified water for public recreational places. Most of the water used in Windhoek is reclaimed by City of Windhoek. To better illustrate this to the pupils, a school trip with 40 pupils of seventh grade was taken to the City of Windhoek's Gammams Water Care works. The aim of the trip was to show how the sewage purification process works and how the water is reclaimed from sewage. A guided tour of the water works was given by the resident scientists and the pupils were provided with the worksheet to complete after the tour around the Centre. They were encouraged to ask questions in all stages of water purification process and write down short notes. Most learners completed their worksheet during the tour session as they are getting information from the tour guide. The rest had to retrieve information and do further research as they got back to class so they could complete their worksheets. After the tour to Gammams, learners were asked to share what they had learned with the lower grades, 5 and 6, in a classroom

  1. Polyaniline-coated cigarette filters as a solid-phase extraction sorbent for the extraction and enrichment of polycyclic aromatic hydrocarbon in water samples.

    Science.gov (United States)

    Bunkoed, Opas; Rueankaew, Thanaschaphorn; Nurerk, Piyaluk; Kanatharana, Proespichaya

    2016-06-01

    Polyaniline coated cigarette filters were successfully synthesized and used as a solid-phase extraction sorbent for the extraction and preconcentration of polycyclic aromatic hydrocarbons in water samples. The polyaniline helped to enhance the adsorption ability of polycyclic aromatic hydrocarbons on the sorbent through π-π interactions. The high porosity and large surface area of the cigarette filters helped to reduce backpressure and can be operated with high sample flow rate without loss of extraction efficiency. The developed sorbent was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The parameters that affected the extraction efficiencies, i.e. polymerization time, type of desorption solvent and its volume, sample flow rate, sample volume, sample pH, ionic strength, and organic modifier were investigated. Under the optimal conditions, the method was linear over the range of 0.5-10 μg/L and a detection limit of 0.5 ng/L. This simple, rapid, and cost-effective method was successfully applied to the preconcentration of polycyclic aromatic hydrocarbons from water samples. The developed method provided a high enrichment factor with good extraction efficiency (85-98%) and a relative standard deviation <10%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Cesium removal from the fuel storage water at the Savannah River Site R-Building Disassembly Basin using 3M Empore reg-sign-membrane filter technology

    International Nuclear Information System (INIS)

    Oji, L.N.; Thompson, M.C.; Peterson, K.; May, C.; Kafka, T.M.

    1998-01-01

    This report describes results from a seven-day demonstration of the use of 3M Empore membrane filter loaded with ion exchange material (potassium cobalt hexacynoferrate (CoHex)) for cesium uptake from the R-Disassembly Basin at the Savannah River Site. The goal of the demonstration was to evaluate the ability of the Process Absorber Development unit (PADU), a water pre-filtration /CoHex configuration on a skid, to remove cesium from R-Disassembly Basin at a linear processing flow rate of 22.7 liters per minute (1,195.8 liters/minute/m 2 or 29.35 gallons/minute/ft 2 ). Over 210,000 liters (> 55,500 gallons) of R-Disassembly Basin water was processed through the PADU without a cesium breakthrough, that is, the effluent after treatment with CoHex, contained less than detectable amounts of radioactive cesium. Some of the observed advantages of the Empore membrane filter technology over conventional packed column ion exchange systems includes rapid flow rates without channeling effects, low volume secondary waste and fast extraction or rapid kinetics per unit of flow

  3. Detection of chemical substances in water using an oxide nanowire transistor covered with a hydrophobic nanoparticle thin film as a liquid-vapour separation filter

    Directory of Open Access Journals (Sweden)

    Taekyung Lim

    2016-08-01

    Full Text Available We have developed a method to detect the presence of small amounts of chemical substances in water, using a Al2O3 nanoparticle thin film covered with phosphonic acid (HDF-PA self-assembled monolayer. The HDF-PA self-assembled Al2O3 nanoparticle thin film acts as a liquid-vapour separation filter, allowing the passage of chemical vapour while blocking liquids. Prevention of the liquid from contacting the SnO2 nanowire and source-drain electrodes is required in order to avoid abnormal operation. Using this characteristic, the concentration of chemical substances in water could be evaluated by measuring the current changes in the SnO2 nanowire transistor covered with the HDF-PA self-assembled Al2O3 nanoparticle thin film.

  4. Development of a method for rapid and simultaneous monitoring of particulate and dissolved radiocesium in water with nonwoven fabric cartridge filters

    International Nuclear Information System (INIS)

    Hideki Tsuji; Tetsuo Yasutaka; Yoshihiko Kondo; Yasukazu Suzuki

    2014-01-01

    A method for the rapid and simultaneous monitoring of particulate and dissolved 137 Cs concentration in water was developed. This method uses pleated polypropylene nonwoven fabric filter to collect particulate radiocesium, and nonwoven fabric impregnated with Prussian blue (PB) to absorb dissolved radiocesium. The fabric was placed into cylindrical plastic cartridges (SS-cartridge and PB-cartridge). Traditional monitoring methods, such as evaporative concentration, often require time for pre-processing. However, this method described requires much less pre-processing time before the detection. Experiments conducted with simulated river water demonstrated that almost all of the suspended solids weight was collected in the SS-cartridge, and that more than 92 % of dissolved 137 Cs was absorbed onto the two PB-cartridges by 2.5 L/min flow rate when the range of the pH was 6-8. This device was applied to monitor Abukuma River water at two locations and the results were compared with those obtained using the filtrating and evaporative concentration method. The suspended solids concentration in river water, calculated by weight gain of the SS-cartridge and by sediment weight after filtration with a 0.45-μm membrane filter, agreed well. The radioactivity of the particulate and dissolved 137 Cs also agreed well in one of the two replications of this method. In addition, the required time for pre-processing was reduced by 60 times that by filtrating and evaporative concentration method. This method can separately collect and concentrate particulate and dissolved radiocesium rapidly and simultaneously in the field. (author)

  5. Public health risk status of the water supply frame work at Kwame ...

    African Journals Online (AJOL)

    The aim of the study is to assess the public health risk status of the potable water supply framework at the Kwame Nkurumah Postgraduate Residence (PG) Hall, University of Nigeria, Nsukka, (UNN), Enugu State, Nigeria, and environs. Four potable water supply frame-works at the PG Hall, UNN, and exposed stagnant ...

  6. Evaluation of a mechanistic algorithm to calculate the influence of a shallow water table on hydrology sediment and pesticide transport through vegetative filter strips

    Science.gov (United States)

    Lauvernet, C.; Munoz-Carpena, R.; Carluer, N.

    2012-04-01

    Natural or introduced areas of vegetation, also known as vegetative filter strips (VFS), are a common environmental control practice to protect surface water bodies from human influence. In Europe, VFS are placed along the water network to protect from agrochemical drift during applications, in addition to runoff control. Their bottomland placement next to the streams often implies the presence of a seasonal shallow water table which can have a profound impact on the efficiency of the buffer zone (Lacas et al. 2005). A physically-based algorithm describing ponded infiltration into soils bounded by a water table, proposed by Salvucci and Enthekabi (1995), was further developed to simulate VFS dynamics by making it explicit in time, account for unsteady rainfall conditions, and by coupling to a numerical overland flow and transport model (VFSMOD) (Munoz-Carpena et al., submitted). In this study, we evaluate the importance of the presence of a shallow water table on filter efficiency (reductions in runoff, sediment and pesticide mass), in the context of all other input factors used to describe the system. Global sensitivity analysis (GSA) was used to rank the important input factors and the presence of interactions, as well as the contribution of the important factors to the output variance. GSA of VSFMOD modified for shallow water table was implemented on 2 sites selected in France because they represent different agro-pedo-climatic conditions for which we can compare the role of the factors influencing the performance of grassed buffer strips for surface runoff, sediment and pesticide removal. The first site at Morcille watershed in the Beaujolais wineyard (Rhône-Alpes) contains a very permeable sandy-clay with water table depth varying with the season (very deep in summer and shallow in winter), with a high slope (20 to 30%), and subject to strong seasonal storms (semi-continental, Mediterranean climate). The second site at La Jailliere (Loire-Atlantique, ARVALIS

  7. High flow ceramic pot filters

    NARCIS (Netherlands)

    van Halem, D.; van der Laan, H.; Soppe, A. I.A.; Heijman, S.G.J.

    2017-01-01

    Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more

  8. Kaon Filtering For CLAS Data

    International Nuclear Information System (INIS)

    McNabb, J.

    2001-01-01

    The analysis of data from CLAS is a multi-step process. After the detectors for a given running period have been calibrated, the data is processed in the so called pass-1 cooking. During the pass-1 cooking each event is reconstructed by the program a1c which finds particle tracks and computes momenta from the raw data. The results are then passed on to several data monitoring and filtering utilities. In CLAS software, a filter is a parameterless function which returns an integer indicating whether an event should be kept by that filter or not. There is a main filter program called g1-filter which controls several specific filters and outputs several files, one for each filter. These files may then be analyzed separately, allowing individuals interested in one reaction channel to work from smaller files than using the whole data set would require. There are several constraints on what the filter functions should do. Obviously, the filtered files should be as small as possible, however the filter should also not reject any events that might be used in the later analysis for which the filter was intended

  9. Multi-filter spectrophotometry simulations

    Science.gov (United States)

    Callaghan, Kim A. S.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    To complement both the multi-filter observations of quasar environments described in these proceedings, as well as the proposed UBC 2.7 m Liquid Mirror Telescope (LMT) redshift survey, we have initiated a program of simulated multi-filter spectrophotometry. The goal of this work, still very much in progress, is a better quantitative assessment of the multiband technique as a viable mechanism for obtaining useful redshift and morphological class information from large scale multi-filter surveys.

  10. Autoregressive Moving Average Graph Filtering

    OpenAIRE

    Isufi, Elvin; Loukas, Andreas; Simonetto, Andrea; Leus, Geert

    2016-01-01

    One of the cornerstones of the field of signal processing on graphs are graph filters, direct analogues of classical filters, but intended for signals defined on graphs. This work brings forth new insights on the distributed graph filtering problem. We design a family of autoregressive moving average (ARMA) recursions, which (i) are able to approximate any desired graph frequency response, and (ii) give exact solutions for tasks such as graph signal denoising and interpolation. The design phi...

  11. Sorption and desorption of arsenic to ferrihydrite in a sand filter.

    Science.gov (United States)

    Jessen, Soren; Larsen, Flemming; Koch, Christian Bender; Arvin, Erik

    2005-10-15

    Elevated arsenic concentrations in drinking water occur in many places around the world. Arsenic is deleterious to humans, and consequently, As water treatment techniques are sought. To optimize arsenic removal, sorption and desorption processes were studied at a drinking water treatment plant with aeration and sand filtration of ferrous iron rich groundwater at Elmevej Water Works, Fensmark, Denmark. Filter sand and pore water were sampled along depth profiles in the filters. The sand was coated with a 100-300 microm thick layer of porous Si-Ca-As-contaning iron oxide (As/Fe = 0.17) with locally some manganese oxide. The iron oxide was identified as a Si-stabilized abiotically formed two-line ferrihydrite with a magnetic hyperfine field of 45.8 T at 5 K. The raw water has an As concentration of 25 microg/L, predominantly as As(II). As the water passes through the filters, As(III) is oxidized to As(V) and the total concentrations drop asymptotically to a approximately 15 microg/L equilibrium concentration. Mn is released to the pore water, indicating the existence of reactive manganese oxides within the oxide coating, which probably play a role for the rapid As(III) oxidation. The As removal in the sand filters appears controlled by sorption equilibrium onto the ferrihydrite. By addition of ferrous chloride (3.65 mg of Fe(II)/L) to the water stream between two serially connected filters, a 3 microg/L As concentration is created in the water that infiltrates into the second sand filter. However, as water flow is reestablished through the second filter, As desorbs from the ferrihydrite and increases until the 15 microg/L equilibrium concentration. Sequential chemical extractions and geometrical estimates of the fraction of surface-associated As suggest that up to 40% of the total As can be remobilized in response to changes in the water chemistry in the sand filter.

  12. Buffers and vegetative filter strips

    Science.gov (United States)

    Matthew J. Helmers; Thomas M. Isenhart; Michael G. Dosskey; Seth M. Dabney

    2008-01-01

    This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards.

  13. Work plan for ground water elevation data recorder/monitor well installation at Gunnison, Colorado

    International Nuclear Information System (INIS)

    1994-01-01

    The purpose of this document is to describe the work that will be performed and the procedures that will be followed during installation of ground water monitor wells and ground water elevation data recorders (data loggers) at the Gunnison, Colorado, Uranium Mill Tailings Remedial Action (UMTRA) Project site. The monitor wells and data loggers will be used to gather required time-dependent data to investigate the interaction between ground water and surface water in the area. Data collection objectives (DCO) identify reasons for collecting data. The following are DCOs for the Gunnison ground water elevation data recorder/monitor well installation project: long-term continuous ground water level data and periodic ground water samples will be collected to better understand the relationship between surface and ground water at the site; water level and water quality data will eventually be used in future ground water modeling to more firmly establish boundary conditions in the vicinity of the Gunnison processing site; and modeling results will be used to demonstrate and document the potential remedial alternative of natural flushing

  14. Hydrodynamics of microbial filter feeding.

    Science.gov (United States)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia; Walther, Jens H; Kiørboe, Thomas; Andersen, Anders

    2017-08-29

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate amounts of water. Also, the trade-off in the filter spacing remains unexplored, despite its simple formulation: A filter too coarse will allow suitably sized prey to pass unintercepted, whereas a filter too fine will cause strong flow resistance. We quantify the feeding flow of the filter-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet), something notoriously difficult to visualize but sporadically observed in the related choanocytes (sponges). A CFD model with a flagellar vane correctly predicts the filtration rate of D. grandis , and using a simple model we can account for the filtration rates of other microbial filter feeders. We finally predict how optimum filter mesh size increases with cell size in microbial filter feeders, a prediction that accords very well with observations. We expect our results to be of significance for small-scale biophysics and trait-based ecological modeling.

  15. Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

    Science.gov (United States)

    Lin, Yuan-Pei; Vaidyanathan, P. P.

    1994-01-01

    None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

  16. Implementation of Kalman filter algorithm on models reduced using singular pertubation approximation method and its application to measurement of water level

    Science.gov (United States)

    Rachmawati, Vimala; Khusnul Arif, Didik; Adzkiya, Dieky

    2018-03-01

    The systems contained in the universe often have a large order. Thus, the mathematical model has many state variables that affect the computation time. In addition, generally not all variables are known, so estimations are needed to measure the magnitude of the system that cannot be measured directly. In this paper, we discuss the model reduction and estimation of state variables in the river system to measure the water level. The model reduction of a system is an approximation method of a system with a lower order without significant errors but has a dynamic behaviour that is similar to the original system. The Singular Perturbation Approximation method is one of the model reduction methods where all state variables of the equilibrium system are partitioned into fast and slow modes. Then, The Kalman filter algorithm is used to estimate state variables of stochastic dynamic systems where estimations are computed by predicting state variables based on system dynamics and measurement data. Kalman filters are used to estimate state variables in the original system and reduced system. Then, we compare the estimation results of the state and computational time between the original and reduced system.

  17. Generalised Filtering

    Directory of Open Access Journals (Sweden)

    Karl Friston

    2010-01-01

    Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

  18. Filter This

    Directory of Open Access Journals (Sweden)

    Audrey Barbakoff

    2011-03-01

    Full Text Available In the Library with the Lead Pipe welcomes Audrey Barbakoff, a librarian at the Milwaukee Public Library, and Ahniwa Ferrari, Virtual Experience Manager at the Pierce County Library System in Washington, for a point-counterpoint piece on filtering in libraries. The opinions expressed here are those of the authors, and are not endorsed by their employers. [...

  19. Variable Span Filters for Speech Enhancement

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Benesty, Jacob; Christensen, Mads Græsbøll

    2016-01-01

    In this work, we consider enhancement of multichannel speech recordings. Linear filtering and subspace approaches have been considered previously for solving the problem. The current linear filtering methods, although many variants exist, have limited control of noise reduction and speech...

  20. Evaluation of a treatment system type septic tank - filter anaerobic of upward flow for the residual waters of the ecological benefit of the coffee

    International Nuclear Information System (INIS)

    Sanchez C, Jose Alejandro

    1997-01-01

    Colombia is the first country in the production of soft coffee in the world. The benefit for humid way it makes that this quality of coffee is obtained; however, the high consumption of water in the process and the later discharge to the superficial or underground sources, they have generated an environmental problem of great magnitude. Also, the sources of water that they have been contaminated with the discharges of the liquid waste that come from benefit of coffee they present, among other, serious inconveniences to be used as supplying sources of drinkable water. In time of crop, the coffee areas and their superficial sources of water usually register high indexes of contamination like consequence of the discharges of residual waters that come from the benefit of the coffee. In the Departments of Quindio, Valle, Caldas, Antioquia, etc., they have been come executing investigations of the residuals treatment that are derived of the pulp removal of the coffee (via humid), for anaerobic methods with satisfactory results. This project had the collaboration of the Departmental Committee of Coffee of Antioquia and the Environmental Engineering of the Antioquia University and it is formulated toward the evaluation of a Anaerobic filter of Ascendant flow, FAFA, preceded of a septic tank (biological sedimentation), as a treatment system of the coffee residual waters, with a waste native of a ecological benefit area. The obtained results were satisfactory although the generated waste is very intermittent and in times that are not of coffee crop it doesn't take place; what hinders more the application of biological systems for its treatment

  1. High flow ceramic pot filters

    OpenAIRE

    van Halem, D.; van der Laan, H.; Soppe, A. I.A.; Heijman, S.G.J.

    2017-01-01

    Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6–19 L h−1), but initial LRVs for E. coli o...

  2. Conversion of thermall energy to mechanical work in the oscillations with steam condensation in pool water

    International Nuclear Information System (INIS)

    Aya, Izuo; Nariai, Hideki.

    1988-01-01

    Pressure and fluid oscillations with steam injection into pool water were discussed from the view point of the conversion of thermal energy into mechanical work. When the change of fluid state moves clockwise in the p-V diagram, the oscillation sustains since the thermal energy changes into positive work. The equations difining the mechanical work at the condensation oscillations were presented. The oscillation threshold determined by the condition that mechanical work became zero, coincided with the values derived by the linear oscillation theory. The changes of pressure and specific volume during chugging were also shown with one dimensional simulation analysis. The p-V diagrams at various chugging modes were presented with the movement of steam water interface, and the conversion efficiency of thermal energy to mechanical work was also discussed. (author)

  3. Water works Slatinka, Garajky, Hroncek and Tichy potok for public profit

    International Nuclear Information System (INIS)

    Holcik, V.

    2003-01-01

    There is 2890 towns and villages in Slovak Republic. About 2030 has drinking water from public ducting. Worse situation is in waste water off take - only about 490 villages are connected to public sewerage. It is necessary to have drinking water at disposal (from underground and ground sources), consequently ducting with water finishing department and at the end sewerage with water purifier. But Slovak Republic is country that has never had enough money for such investments as building drinking water basin, to process and distribute water to 38 villages and to build sewerage and water purifier for these villages. If we want to be equal partner to another European Union countries thus all villages above 2000 inhabitants should have ducting and sewerage. In Slovak Republic there is about 295 villages without ducting and sewerage. First, the source is necessary, then duct and then sewerage, not conversely. Structural, cohesive and other European Union funds should be used also for building of drinking water basins and connecting ducts and sewerage. I am confident that water works Slatinka, Garajky, Hroncek and Tichy Potok recommended by Ministry of Land management are necessary to be built and it will be for public profit

  4. Water Worries: The Hidden Costs of Water Conservation in China are not Working

    OpenAIRE

    Junlian Zhang

    2006-01-01

    One of the obstacles many conservation strategies face is the amount of time and money it actually costs for people t o be involved in their implementation - in other words, their "transaction costs" (TCs) . A new study from China has looked at how these costs have affected an innovative market-based water conservation system. The study found that TCs are a significant barrier to proper functioning of the system. It also found that these costs are linked to key social and administrative obsta...

  5. Methods for in-place testing of HEPA and iodine filters used in nuclear power plants

    International Nuclear Information System (INIS)

    Holmberg, R.; Laine, J.

    1978-04-01

    The purpose of this work was a general investigation of existing in-place test methods and to build an equipment for in-place testing of HEPA and iodine sorption filters. In this work the discussion is limited to methods used in in-place testing of HEPA and iodine sorption filters used in light-water-cooled reactor plants. Dealy systems, built for the separation of noble gases, and testing of them is not discussed in the work. Contaminants present in the air of a reactor containment can roughly be diveded into three groups: aerosols, reactive gases, and noble gases. The aerosols are filtered with HEPA (High Efficiency Particulate Air) filters. The most important reactive gases are molecular iodine and its two compounds: hydrogen iodide and methyl iodide. Of gases to be removed by the filters methyl iodide is the gas most difficult to remove especially at high relative humidities. Impregnated activated charcoal is generally used as sorption material in the iodine filters. Experience gained from the use of nuclear power plants proves that the function of high efficiency air filter systems can not be considered safe until this is proved by in-place tests. In-place tests in use are basically equal. A known test agent is injected upstream of the filter to be tested. The efficiency is calculated from air samples taken from both sides of the filter. (author)

  6. A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

    2017-07-01

    Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

  7. Reconfigurable Mixed Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    Neelofer Afzal

    2014-01-01

    Full Text Available This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters.

  8. Evaluating the Role of Total Organic Carbon in Predicting the Treatment Efficacy of Biosand Filters for the Removal of Vibrio cholerae in Drinking Water During Startup.

    Science.gov (United States)

    Danley-Thomson, Ashley A; Huang, Ellen C; Worley-Morse, Thomas; Gunsch, Claudia K

    2018-05-09

    In biosand filters (BSF), treatment is largely driven by the development of a biolayer (schmutzdecke) which establishes itself during the startup phase. In the present study, the effect of changing influent total organic carbon (TOC) loading on the removal efficiency of Vibrio cholerae in laboratory-operated BSFs was quantified. BSFs were charged with high, medium or low TOC influents and removal efficacy and schmutzdecke composition was monitored over two months. The highest V. cholerae removal efficiencies were observed in the BSF receiving the lowest TOC. Schmutzdecke composition was found to be influenced by influent TOC, in terms of microbial community structure and amount of extracellular polymeric substance (EPS). Physical/chemical attachment was shown to be important during startup. The BSF receiving influent water with lower TOC had a higher attachment coefficient than the BSF receiving high TOC water, suggesting more physical/chemical treatment in the lower TOC BSF. The high TOC BSF had more EPS than did the biofilm from the low TOC BSF, suggesting that schmutzdecke effects may be more significant at high TOC. Overall, this study confirms that influent water characteristics will affect BSF treatment efficacy of V. cholerae especially during the startup phase. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Hybrid coagulation-UF processes for spent filter backwash water treatment: a comparison studies for PAFCl and FeCl3 as a pre-treatment.

    Science.gov (United States)

    Ebrahimi, Afshin; Amin, Mohammad Mehdi; Pourzamani, Hamidreza; Hajizadeh, Yaghoub; Mahvi, Amir Hossein; Mahdavi, Mokhtar; Rad, Mohammad Hassan Rabie

    2017-08-01

    In this study, the reclamation of clean water from spent filter backwash water (SFBW) was investigated through pilot-scale experiments. The pilot plant consisted of pre-sedimentation, coagulation, flocculation, clarification, and ultrafiltration (UF). Two coagulants of PAFCl and FeCl 3 were investigated with respect to their performance on treated SFBW quality and UF membrane fouling. At the optimum dose of PAFCl and FeCl 3 turbidity removal of 99.6 and 99.4% was attained, respectively. PAFCl resulted in an optimum UV 254 , TOC, and DOC removal of 80, 83.6, and 72.7%, respectively, and FeCl 3 caused the removal of those parameters by 76.7, 80.9, and 65.9%, respectively. PAFCl removed hydrophilic and transphilic constituent better than FeCl 3 , but FeCl 3 had, to some extent, higher affinities to a hydrophobic fraction. It was concluded that PAFCl showed a better coagulation performance in most cases and caused a lower membrane fouling rate compared to FeCl 3 . Finally, the treated SFBW with both coagulant-UF systems met the drinking water standards.

  10. A graphite calorimeter for absolute measurements of absorbed dose to water: application in medium-energy x-ray filtered beams.

    Science.gov (United States)

    Pinto, M; Pimpinella, M; Quini, M; D'Arienzo, M; Astefanoaei, I; Loreti, S; Guerra, A S

    2016-02-21

    The Italian National Institute of Ionizing Radiation Metrology (ENEA-INMRI) has designed and built a graphite calorimeter that, in a water phantom, has allowed the determination of the absorbed dose to water in medium-energy x-rays with generating voltages from 180 to 250 kV. The new standard is a miniaturized three-bodies calorimeter, with a disc-shaped core of 21 mm diameter and 2 mm thickness weighing 1.134 g, sealed in a PMMA waterproof envelope with air-evacuated gaps. The measured absorbed dose to graphite is converted into absorbed dose to water by means of an energy-dependent conversion factor obtained from Monte Carlo simulations. Heat-transfer correction factors were determined by FEM calculations. At a source-to-detector distance of 100 cm, a depth in water of 2 g cm(-2), and at a dose rate of about 0.15 Gy min(-1), results of calorimetric measurements of absorbed dose to water, D(w), were compared to experimental determinations, D wK, obtained via an ionization chamber calibrated in terms of air kerma, according to established dosimetry protocols. The combined standard uncertainty of D(w) and D(wK) were estimated as 1.9% and 1.7%, respectively. The two absorbed dose to water determinations were in agreement within 1%, well below the stated measurement uncertainties. Advancements are in progress to extend the measurement capability of the new in-water-phantom graphite calorimeter to other filtered medium-energy x-ray qualities and to reduce the D(w) uncertainty to around 1%. The new calorimeter represents the first implementation of in-water-phantom graphite calorimetry in the kilovoltage range and, allowing independent determinations of D(w), it will contribute to establish a robust system of absorbed dose to water primary standards for medium-energy x-ray beams.

  11. Modeling the impact of drought on canopy carbon and water fluxes for a subtropical evergreen coniferous plantation in southern China through parameter optimization using an ensemble Kalman filter

    Directory of Open Access Journals (Sweden)

    W. Ju

    2010-03-01

    Full Text Available Soil and atmospheric water deficits have significant influences on CO2 and energy exchanges between the atmosphere and terrestrial ecosystems. Model parameterization significantly affects the ability of a model to simulate carbon, water, and energy fluxes. In this study, an ensemble Kalman filter (EnKF and observations of gross primary productivity (GPP and latent heat (LE fluxes were used to optimize model parameters significantly affecting the calculation of these fluxes for a subtropical coniferous plantation in southeastern China. The optimized parameters include the maximum carboxylation rate (Vcmax, the slope in the modified Ball-Berry model (M and the coefficient determining the sensitivity of stomatal conductance to atmospheric water vapor deficit (D0. Optimized Vcmax and M showed larger variations than D0. Seasonal variations of Vcmax and M were more pronounced than the variations between the two years. Vcmax and M were associated with soil water content (SWC. During dry periods, SWC at the 20 cm depth explained 61% and 64% of variations of Vcmax and M, respectively. EnKF parameter optimization improved the simulations of GPP, LE and SH, mainly during dry periods. After parameter optimization using EnKF, the variations of GPP, LE and SH explained by the model increased by 1% to 4% at half-hourly steps and by 3% to 5% at daily time steps. Further efforts are needed to differentiate the real causes of parameter variations and improve the ability of models to describe the change of stomatal conductance with net photosynthesis rate and the sensitivity of photosynthesis capacity to soil water stress under different environmental conditions.

  12. Photodegradation of the UV filter ethylhexyl methoxycinnamate under ultraviolet light: Identification and in silico assessment of photo-transformation products in the context of grey water reuse.

    Science.gov (United States)

    Jentzsch, F; Olsson, O; Westphal, J; Reich, M; Leder, C; Kümmerer, K

    2016-12-01

    To prevent water shortages in the future and to reduce domestic water consumption, decentralized grey water (GW) reuse has become increasingly important. This water has, however, to be free of pollutants. Conventional treatment of GW does not fully eliminate micropollutants such as the UV filter substance ethylhexyl methoxycinnamate (EHMC). EHMC, which is commonly used in sunscreens and personal care products, is an endocrine disruptor and shows potential to bioaccumulation, which is also reflected in its low water solubility. Photolysis has been proposed as an alternative treatment method for other micropollutants, but it is not clear yet whether it can also be used to eliminate EHMC. One goal of this study was to better understand the basic pathways involved in this process. It aimed to identify photo-transformation products (photo-TPs) by using, in the test conditions, an initial concentration of EHMC higher than those expected in the environment. Acetonitrile (ACN) was added in low concentrations to the aqueous solution to overcome the low aquatic solubility of EHMC. The influence of this co-solvent on the degradation kinetics was studied. The photolysis experiments were carried out using a medium pressure mercury lamp, which emits UV light in the range of 200-400nm. The quantum yield of the photolysis of EHMC was 0.0042 and 0.0023mol·Einstein -1 (for 0.2 and 0.5% ACN (v/v), respectively), and the relative and absolute UV photon fluxes were determined. HPLC was used to monitor the elimination kinetics of EHMC, which followed first-order kinetics. The results of LC-MS n analyses revealed that beside others, several oxidized and hydroxylized EHMC isomers were formed as photo-TPs in aqueous solution. Using a set of in silico quantitative structure-activity relationship (QSAR) models, this study also offered new insights concerning the environmental fate and toxicity of the TPs of EHMC. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Adaptive digital filters

    CERN Document Server

    Kovačević, Branko; Milosavljević, Milan

    2013-01-01

    “Adaptive Digital Filters” presents an important discipline applied to the domain of speech processing. The book first makes the reader acquainted with the basic terms of filtering and adaptive filtering, before introducing the field of advanced modern algorithms, some of which are contributed by the authors themselves. Working in the field of adaptive signal processing requires the use of complex mathematical tools. The book offers a detailed presentation of the mathematical models that is clear and consistent, an approach that allows everyone with a college level of mathematics knowledge to successfully follow the mathematical derivations and descriptions of algorithms.   The algorithms are presented in flow charts, which facilitates their practical implementation. The book presents many experimental results and treats the aspects of practical application of adaptive filtering in real systems, making it a valuable resource for both undergraduate and graduate students, and for all others interested in m...

  14. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    D'Agostino, Maria-Antonietta; Boers, Maarten; Kirwan, John

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imaging...... using the original OMERACT Filter and the newly proposed structure. Breakout groups critically reviewed the extent to which the candidate biomarkers complied with the proposed stepwise approach, as a way of examining the utility of the proposed 3-dimensional structure. RESULTS: Although...... was obtained for a proposed tri-axis structure to assess validation of imaging and soluble biomarkers; nevertheless, additional work is required to better evaluate its place within the OMERACT Filter 2.0....

  15. Preparation of Porcelanite Ceramic Filter by Slip Casting Technique

    Directory of Open Access Journals (Sweden)

    Majid Muhi Shukur

    2016-09-01

    Full Text Available This work is conducted to study producing solid block porcelanite filter from Iraqi porcelanite rocks and kaolin clay (as binder material by slip casting technique, and investigating its ability of removing contaminant (Pentachlorophenol from water via the adsorption mechanism. Four particle sizes (74, 88, 105 and 125 µm of porcelanite powder were used. Each batch of particle size was mixed with (30 wt. % kaolin as a binding material to improve the mechanical properties. After that, the mixtures were formed by slip casting to disk and cylindrical filter samples, and then fired at 500 and 700 °C to specify the effects of particle size of porcelanite, temperature and formation technique on porcelanite filter properties. Some physical, mechanical and chemical tests have been done on filter samples. Multi-experiments were carried out to evaluate the ability of porcelanite to form the filter. Porosity, permeability and maximum pore diameter were increased with increasing porcelanite particle size and decreased by increasing temperature, whereas the density shows the reverse behavior. In addition, bending, compressive and tensile strength of samples were increased by increasing temperature, and decreased with increasing porcelanite particle size. Efficiency of disk filter sample to remove pentachlorophenol was 95.41% at a temperature of 700°C using 74 µm particle size of porcelanite. While the efficiency of cylindrical filter sample was 97.57% at the same conditions.

  16. Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

    Directory of Open Access Journals (Sweden)

    M. Z. Bieroza

    2010-04-01

    Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies. The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

  17. Four decades of working experience of Cirus primary cooling water heat exchangers

    International Nuclear Information System (INIS)

    Dubey, P.K.; Ullas, O.P.; Rao, D.V.H.; Zope, A.K.; Kharpate, A.V.

    2006-01-01

    CIRUS is a 40 MW (Th.) research reactor, commissioned in the year 1960. The reactor has natural uranium fuel rods, heavy water as moderator, demineralised water (DM water) as primary coolant, and seawater as secondary coolant. There are six Heat Exchangers in the primary cooling water (PCW) system. Five of them are required for the normal operation of the reactor and one is kept stand by. DM water flows on the shell side of the heat exchanger in two passes. Seawater is used as coolant on the tube side of the heat exchangers in four passes. Cirus has been in operation for around 41 years excluding refurbishment period. During these four decades of reactor operation, PCW heat exchangers have experienced many failures and undergone many modifications in the circuit for ensuring better performance. This paper tries to capture the essence of working experiences with PCW heat exchangers, various problems faced, remedial measures taken during those four decades of reactor operation. (author)

  18. Ceramic Filter for Small System Drinking Water Treatment: Evaluation of Membrane Pore Size and Importance of Integrity Monitoring

    Science.gov (United States)

    Ceramic filtration has recently been identified as a promising technology for drinking water treatment in households and small communities. This paper summarizes the results of a pilot-scale study conducted at the U.S. Environmental Protection Agency’s (EPA’s) Test & Evaluation ...

  19. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon

    2016-01-08

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  20. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon; Chernov, Alexey; Law, Kody; Nobile, Fabio; Tempone, Raul

    2016-01-01

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  1. Phototransformation of the sunlight filter benzophenone-3 (2-hydroxy-4-methoxybenzophenone) under conditions relevant to surface waters.

    Science.gov (United States)

    Vione, Davide; Caringella, Rosalinda; De Laurentiis, Elisa; Pazzi, Marco; Minero, Claudio

    2013-10-01

    The UV filter benzophenone-3 (BP3) has UV photolysis quantum yield ΦBP3=(3.1±0.3)·10(-5) and the following second-order reaction rate constants: with (•)OH, k(BP3,(•)OH)=(2.0±0.4)·10(10) M(-1) s(-1); with the triplet states of chromophoric dissolved organic matter ((3)CDOM*), K(BP3,(3)CDOM*)=(1.1±0.1)·10(9) M(-1) s(-1); with (1)O2, k(BP3,(1)O2)=(2.0±0.1)·10(5) M(-1) s(-1), and with CO3(-•), k(BP3,CO3(-•))CDOM* would be the main processes of BP3 phototransformation. Reaction with (•)OH would prevail at low DOC, direct photolysis at intermediate DOC (around 5 mg C L(-1)), and reaction with (3)CDOM* at high DOC. If the reaction rate constant with CO3(-•) is near the upper limit of experimental measures (5·10(7) M(-1) s(-1)), the CO3(-•) degradation process could be somewhat important for DOCDOC. BP3 transformation intermediates were detected upon reaction with (•)OH. Two methylated derivatives were tentatively identified, and they were probably produced by reaction between BP3 and fragments arising from photodegradation. The other intermediates were benzoic acid (maximum concentration ~10% of initial BP3) and benzaldehyde (1%). Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Testing particle filters on convective scale dynamics

    Science.gov (United States)

    Haslehner, Mylene; Craig, George. C.; Janjic, Tijana

    2014-05-01

    Particle filters have been developed in recent years to deal with highly nonlinear dynamics and non Gaussian error statistics that also characterize data assimilation on convective scales. In this work we explore the use of the efficient particle filter (P.v. Leeuwen, 2011) for convective scale data assimilation application. The method is tested in idealized setting, on two stochastic models. The models were designed to reproduce some of the properties of convection, for example the rapid development and decay of convective clouds. The first model is a simple one-dimensional, discrete state birth-death model of clouds (Craig and Würsch, 2012). For this model, the efficient particle filter that includes nudging the variables shows significant improvement compared to Ensemble Kalman Filter and Sequential Importance Resampling (SIR) particle filter. The success of the combination of nudging and resampling, measured as RMS error with respect to the 'true state', is proportional to the nudging intensity. Significantly, even a very weak nudging intensity brings notable improvement over SIR. The second model is a modified version of a stochastic shallow water model (Würsch and Craig 2013), which contains more realistic dynamical characteristics of convective scale phenomena. Using the efficient particle filter and different combination of observations of the three field variables (wind, water 'height' and rain) allows the particle filter to be evaluated in comparison to a regime where only nudging is used. Sensitivity to the properties of the model error covariance is also considered. Finally, criteria are identified under which the efficient particle filter outperforms nudging alone. References: Craig, G. C. and M. Würsch, 2012: The impact of localization and observation averaging for convective-scale data assimilation in a simple stochastic model. Q. J. R. Meteorol. Soc.,139, 515-523. Van Leeuwen, P. J., 2011: Efficient non-linear data assimilation in geophysical

  3. Evaluate of head loss, sediment value and copper removal in sand media (rapid sand filter

    Directory of Open Access Journals (Sweden)

    Daneshi Navab

    2014-06-01

    Full Text Available Along with the technology development and increasing consumption of water resources, we are experiencing low qualities in the mentioned resources. Copper brings about serious environment al pollution, threatening human health and ecosystem. This metal found variously in water resources and industrial activities. Therefore, it needs to treat the water resources from these excessive amounts. Different methods have used for this reason but the most used method during recent years has been the absorption by economic absorbers such as sand. Rapid sand filters usually used in water and wastewater treatment plants for water clarification. In this research, a single layer gravity rapid sand filter has used to reduce different concentrations of copper. sediment value and head loss arising in filter media is simulated by using combination of Carman-Kozeny, Rose and Gregory models in different discharges of rapid sand filter. Results have shown that with increasing in discharge and decreasing in input copper concentration, arriving time to given head loss, is increasing. In addition, results demonstrated that with increasing in copper concentration in influent, removal efficiency is decreasing somewhat. Results of this research can applied in an appropriate design of rapid sand filter to copper removal, a prediction of rapid sand filter ability to copper removal and an estimation of arising head loss during filter work thus evaluating of time interval backwash. DOI: http://dx.doi.org/10.3126/ije.v3i2.10641 International Journal of the Environment Vol.3(2 2014: 276-286

  4. Climate Change and Water Working Group - User Needs to Manage Hydrclimatic Risk from Days to Decades

    Science.gov (United States)

    Raff, D. A.; Brekke, L. D.; Werner, K.; Wood, A.; White, K. D.

    2012-12-01

    The Federal Climate Change Water Working Group (CCAWWG) provides engineering and scientific collaborations in support of water management. CCAWWG objectives include building working relationships across federal science and water management agencies, provide a forum to share expertise and leverage resources, develop education and training forums, to work with water managers to understand scientific needs and to foster collaborative efforts across the Federal and non-Federal water management and science communities to address those needs. Identifying and addressing water management needs has been categorized across two major time scales: days to a decade and multi-decadal, respectively. These two time periods are termed "Short-Term" and "Long-Term" in terms of the types of water management decisions they support where Short-Term roughly correlates to water management operations and Long-Term roughly correlates to planning activities. This presentation will focus on portraying the identified water management user needs across these two time periods. User Needs for Long-Term planning were identified in the 2011 Reclamation and USACE "Addressing Climate Change in Long-Term Water Resources Planning and Management: User Needs for Improving Tools and Information." User needs for Long-Term planning are identified across eight major categories: Summarize Relevant Literature, Obtain Climate Change Information, Make Decisions About How to Use the Climate Change Information, Assess Natural Systems Response, Assess Socioeconomic and Institutional Response, Assess System Risks and Evaluate Alternatives, Assess and Characterize Uncertainties, and Communicating Results and Uncertainties to Decisionmakers. User Needs for Short-Term operations are focused on needs relative to available or desired monitoring and forecast products from the hydroclimatic community. These needs are presenting in the 2012 USACE, Reclamation, and NOAA - NWS "Short-Term Water Management Decisions: User

  5. The utilization of water courses for the production of electric power. Report from a working group

    International Nuclear Information System (INIS)

    1992-01-01

    The problems connected with damming Danish water courses to enable the production of hydroelectricity are discussed. These constraints are generally related to conservation principles and cultural historical interests. It is observed that attempts are usually made to remove dams constructed in water courses such as streams and brooks, in order to ensure the free passage of fish and small animals and it is the opinion of the working group that this policy should continue to be followed. Otherwise alternative methods (such as fish staircases and fish sluices) should be set up to enable the fish to pass through without getting entangled with any turbines. Consideration must be given to the preservation of items of cultural-historical interest. Where waters are stagnant, at least half of the water volume should be left untouched for fish passage, and in other non-stagnant water areas water should be reserved for fish passage. The amount of necessary water volume should be assessed in individual cases. The local authorities have agreed that legislation on dams, the establishment of fauna and fish passages and the dedication of free waters to fish passage should be coordinated. (AB)

  6. Generation of soluble microbial products by bio-activated carbon filter during drinking water advanced treatment and its influence on spectral characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Hong, E-mail: song.wei0326@163.com [National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Chen, Xin, E-mail: 742702437@qq.com [National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Zhang, Dong, E-mail: zhdongtj7021@sina.com [National Engineering Research Center of Urban Water Resources, Shanghai National Engineering Research Center of Urban Water Resources Co. Ltd, Shanghai 200082 (China); Chen, Hong-bin, E-mail: hbctxc@tongji.edu.cn [National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2016-11-01

    In order to improve our understanding of bio-activated carbon (BAC) filter, the water quality of influent and effluent treated with BAC in a drinking water treatment plant (DWTP) of Shanghai during 2015 was valued. Combining the results from UV{sub 254}, SUVA{sub 254}, dissolved organic carbon (DOC) and scanning electron microscopic (SEM), it is found that performance of BAC treatment will be affected by characteristics of activated carbon (AC), which is relevant to the type of activated carbon (including shape and operating time) in this study. Fluorescence excitation–emission matrix (FEEM) shows that the humification index (HIX) and index of recent autochthonous contribution (BIX) is a reliable indicator to descript the variation of dissolved organic matter (DOM) during BAC process. The pattern of variation in BIX and HIX implies that soluble microbial products (SMPs) are formed and humic-like substances are removed during BAC treatment, which is also confirmed by the change of peaks of FEEM in BAC effluent. Large, positive correlations between SUVA{sub 254} and disinfection by-products formation potential yield (DBPFP yield) demonstrate that UV-absorbing DOM is directly related to the generation of DBPs. Poor correlations of HIX with DBPFP suggest that non-humic substances with UV-absorbing properties play an important role in the generation of DBPs in water with low SUVA{sub 254}. Finally, strong but negative correlations between BIX and DBPFP suggest that vigorous microbial metabolism of BAC results in a decrease in DBPFP. However, the DBPFP yield will be enhanced for the generation of SMPs by BAC, especially in summer. - Highlights: • SMPs can be produced by BAC during drinking water advanced treatment. • BAC can reduce DBPFP, while there are risks associated with increasing DBPFP yield. • SUVA{sub 254} is strongly correlated with the DBPFP yields. • BIX is strongly correlated with DBPFP and THMFP, but weakly with HAAFP.

  7. Generation of soluble microbial products by bio-activated carbon filter during drinking water advanced treatment and its influence on spectral characteristics

    International Nuclear Information System (INIS)

    Shen, Hong; Chen, Xin; Zhang, Dong; Chen, Hong-bin

    2016-01-01

    In order to improve our understanding of bio-activated carbon (BAC) filter, the water quality of influent and effluent treated with BAC in a drinking water treatment plant (DWTP) of Shanghai during 2015 was valued. Combining the results from UV_2_5_4, SUVA_2_5_4, dissolved organic carbon (DOC) and scanning electron microscopic (SEM), it is found that performance of BAC treatment will be affected by characteristics of activated carbon (AC), which is relevant to the type of activated carbon (including shape and operating time) in this study. Fluorescence excitation–emission matrix (FEEM) shows that the humification index (HIX) and index of recent autochthonous contribution (BIX) is a reliable indicator to descript the variation of dissolved organic matter (DOM) during BAC process. The pattern of variation in BIX and HIX implies that soluble microbial products (SMPs) are formed and humic-like substances are removed during BAC treatment, which is also confirmed by the change of peaks of FEEM in BAC effluent. Large, positive correlations between SUVA_2_5_4 and disinfection by-products formation potential yield (DBPFP yield) demonstrate that UV-absorbing DOM is directly related to the generation of DBPs. Poor correlations of HIX with DBPFP suggest that non-humic substances with UV-absorbing properties play an important role in the generation of DBPs in water with low SUVA_2_5_4. Finally, strong but negative correlations between BIX and DBPFP suggest that vigorous microbial metabolism of BAC results in a decrease in DBPFP. However, the DBPFP yield will be enhanced for the generation of SMPs by BAC, especially in summer. - Highlights: • SMPs can be produced by BAC during drinking water advanced treatment. • BAC can reduce DBPFP, while there are risks associated with increasing DBPFP yield. • SUVA_2_5_4 is strongly correlated with the DBPFP yields. • BIX is strongly correlated with DBPFP and THMFP, but weakly with HAAFP.

  8. Application of novel Modified Biological Aerated Filter (MBAF) as a promising post-treatment for water reuse: Modification in configuration and backwashing process.

    Science.gov (United States)

    Nikoonahad, Ali; Ghaneian, Mohammad Taghi; Mahvi, Amir Hossein; Ehrampoush, Mohammad Hassan; Ebrahimi, Ali Asghar; Lotfi, Mohammad Hassan; Salamehnejad, Sima

    2017-12-01

    Biological Aerated Filter (BAF) reactors due to their plentiful biomass, high shockability, high efficiency, good filtration, availability and lack of need for large land areas, are enjoying from great importance in advanced wastewater treatment. Therefore, in this study, Polystyrene Coated by Sand (PCS) was produced as a novel media and its application in a modified down-flow BAF structure for advanced wastewater treatment was assessed in two steps. In step one, the backwash effluent did not return to the system, while in step two backwash effluent returned to increase the water reuse efficiency. The backwash process was also studied through three methods of Top Backwashing (TB), Bottom Backwashing (BB), as well as Top and Bottom Backwashing Simultaneously (TBBS). The results showed that return of backwash effluent had no significant effect on the BAF effluent quality. In the second step similar to the first one with slight differences, the residual average concentrations of TSS, BOD 5 , and COD at the effluent were about 2.5, 8.2, and 25.5 mg/L, respectively. Additionally, in step two, the mean volume of disposal sludge/volume of treated water (v ds /v tw ) decreased a large extent to about 0.088%. In other words, the water reuse has increased to more than 99.91%. The backwash time in methods of TB and BB were 65 and 35 min, respectively; however, it decreased in TBBS methods to 25 min. The concentrations of most effluent parameters in this system are in concordance with the 2012 EPA Agriculture Standards, even for irrigation of Non-processed agricultural crops and livestock water consumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Water on TiO2 studied by work function change: adsorption in cycles

    International Nuclear Information System (INIS)

    Bundaleski, Nenad; Silva, Ana G; Jean-Shaw, Bobbie; Teodoro, Orlando; Moutinho, Augusto

    2013-01-01

    The nature of water adsorption on TiO 2 (110) rutile surface attracts a lot of attention for quite some time. In spite of the considerable experimental and theoretical efforts a lot of details remain unclear. We have been using work function study to follow the adsorption of water on TiO 2 at room temperature, and interpreted the results in terms of fast dissociative adsorption on bridging oxygen vacancies (BOV) and much slower non-dissociative adsorption on Ti 5f rows. Additionally, we concluded that water from Ti 5f rows efficiently desorbs at room temperature which is not the case for BOV adsorption sites. Here we propose a novel experimental approach which consists of monitoring in real-time the work function change during cycles of water adsorption. Since desorption at BOVs does not take place at room temperature, this method allows us to resolve the adsorption dynamics on the two adsorption sites. The first results changed our understanding of the phenomenon: we show that both, adsorption on BOVs and Ti 5f are both very fast. Additionally, slow exponential decay of the work function is observed, which is not directly related to water adsorption. The possible explanation of the third slow contribution could be related to the migration of hydrogen atoms along the bridging oxygen rows.

  10. Visiting students work with professors to research water resources management issues

    OpenAIRE

    Davis, Lynn

    2009-01-01

    Undergraduate students visiting from universities across the continent, as well as one from Virginia Tech, are working with professors at Virginia Tech on individual research projects in a 10-week summer program that addresses issues related to sustainable management of water resources.

  11. International Working Group on Water Reactor Fuel Performance and Technology. Summary report of the 14. plenary meeting. Working material

    International Nuclear Information System (INIS)

    1997-01-01

    The fourteenth Plenary Meeting of the International Working Group on Water Reactor Fuel Performance and Technology (IWGFPT) was held at IAEA Headquarters, Vienna, from 21 to 23 May 1997. Twenty-seven participants, from twenty two Member States and two international organizations, attended the meeting. These presentations generally gave: The general situation of the nuclear industry in the country; Fuel fabrication; Fuel performance, high burnup fuel (including MOX) operational experience; Status and trends in fuel research programmes directed to achievement sufficient safety margins at high burnups with regard to normal and transient operational conditions. Majority of countries reported on the stable situation of the nuclear fuel industry, i.e. without significant additions/cuts in nuclear power plant and fuel fabrication plant (NPP) capacities. Refs, figs, tabs

  12. International Working Group on Water Reactor Fuel Performance and Technology. Summary report of the 14. plenary meeting. Working material

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    The fourteenth Plenary Meeting of the International Working Group on Water Reactor Fuel Performance and Technology (IWGFPT) was held at IAEA Headquarters, Vienna, from 21 to 23 May 1997. Twenty-seven participants, from twenty two Member States and two international organizations, attended the meeting. These presentations generally gave: The general situation of the nuclear industry in the country; Fuel fabrication; Fuel performance, high burnup fuel (including MOX) operational experience; Status and trends in fuel research programmes directed to achievement sufficient safety margins at high burnups with regard to normal and transient operational conditions. Majority of countries reported on the stable situation of the nuclear fuel industry, i.e. without significant additions/cuts in nuclear power plant and fuel fabrication plant (NPP) capacities. Refs, figs, tabs.

  13. Effect of cold work hardening on stress corrosion cracking of stainless steels in primary water of pressurized water reactors

    International Nuclear Information System (INIS)

    Raquet, O.; Herms, E.; Vaillant, F.; Couvant, T.; Boursier, J.M.

    2004-01-01

    A R and D program is carried out in CEA and EDF laboratories to investigate separately the effects of factors which could contribute to IASCC mechanism. In the framework of this study, the influence of cold work on SCC of ASSs in primary water is studied to supply additional knowledge concerning the contribution of radiation hardening on IASCC of ASSs. Solution annealed ASSs, essentially of type AISI 304(L) and AISI 316(L), are generally considered very resistant to SCC in nominal primary water. However, Constant Extension Rate Tests (CERTs), performed on cold pressed humped specimens in nominal primary water at 360 deg. C, reveal that these materials can exhibit a high SCC susceptibility: deepest cracks reach 1 mm (mean crack growth rate about 1 μm.h -1 ) and propagation is mainly intergranular for 304L and mainly transgranular for 316L. Indeed, work hardening in conjunction with high localized deformation can promote SCC. The influence of the nature of the cold work (shot peening, reaming, cold rolling, counter sinking, fatigue work hardening and tensile deformation) is investigated by means of screening CERTs performed with smooth specimens in 304L at 360 deg. C. For a given cold work hardening level, the susceptibility to crack initiation strongly depends on the cold working process, and no propagation is observed for a hardness level lower than 300 ±10 HV(0.49N). The propagation of cracks is observed only for dynamic loadings like CERT, traction/relaxation tests and crack growth rate tests performed with CT specimens under trapezoidal loading. Although crack initiation is observed for constant load and constant deformation tests, crack propagation do not seem to occur under these mechanical solicitations for 17000 hours of testing, even for hardness levels higher than 450 HV(0.49N). The mean crack growth rate increases when the hardness increases. An important R and D program is in progress to complement these results and to develop a SCC model for ASSs in

  14. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude......; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet...

  15. Apparatus for filtering radioactive fluids

    International Nuclear Information System (INIS)

    Gischel, E.H.

    1975-01-01

    Apparatus is provided for filtering radioactive particles from the cooling and/or auxiliary process water of a nuclear reactor, or nuclear fuel processing plant, or other installations wherein radioactive fluid systems are known to exist. The apparatus affords disposal of the captured particles in a manner which minimizes the exposure of operating personnel to radioactivity. The apparatus comprises a housing adapted to contain a removable filter cartridge assembly, a valve normally closing the lower end of the housing, an upwardly-open shipping cask located below the valve, and an elongated operating rod assembly projecting upwardly from the filter cartridge assembly and through the upper end of the housing to enable a workman to dismount the filter cartridge assembly from its housing and to lower the filter cartridge assembly through the valve and into the cask from a remote location above the housing. (U.S.)

  16. A field study of selected U.S. Geological Survey analytical methods for measuring pesticides in filtered stream water, June - September 2012

    Science.gov (United States)

    Martin, Jeffrey D.; Norman, Julia E.; Sandstrom, Mark W.; Rose, Claire E.

    2017-09-06

    U.S. Geological Survey monitoring programs extensively used two analytical methods, gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry, to measure pesticides in filtered water samples during 1992–2012. In October 2012, the monitoring programs began using direct aqueous-injection liquid chromatography tandem mass spectrometry as a new analytical method for pesticides. The change in analytical methods, however, has the potential to inadvertently introduce bias in analysis of datasets that span the change.A field study was designed to document performance of the new method in a variety of stream-water matrices and to quantify any potential changes in measurement bias or variability that could be attributed to changes in analytical methods. The goals of the field study were to (1) summarize performance (bias and variability of pesticide recovery) of the new method in a variety of stream-water matrices; (2) compare performance of the new method in laboratory blank water (laboratory reagent spikes) to that in a variety of stream-water matrices; (3) compare performance (analytical recovery) of the new method to that of the old methods in a variety of stream-water matrices; (4) compare pesticide detections and concentrations measured by the new method to those of the old methods in a variety of stream-water matrices; (5) compare contamination measured by field blank water samples in old and new methods; (6) summarize the variability of pesticide detections and concentrations measured by the new method in field duplicate water samples; and (7) identify matrix characteristics of environmental water samples that adversely influence the performance of the new method. Stream-water samples and a variety of field quality-control samples were collected at 48 sites in the U.S. Geological Survey monitoring networks during June–September 2012. Stream sites were located across the United States and included sites in agricultural and urban land

  17. On the acoustic filtering of the pipe and sensor in a buried plastic water pipe and its effect on leak detection: an experimental investigation.

    Science.gov (United States)

    Almeida, Fabrício; Brennan, Michael; Joseph, Phillip; Whitfield, Stuart; Dray, Simon; Paschoalini, Amarildo

    2014-03-20

    Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors.

  18. Water quality and head loss in irrigation filters Qualidade da água e perda de carga em filtros de irrigação

    Directory of Open Access Journals (Sweden)

    Túlio Assunção Pires Ribeiro

    2004-12-01

    Full Text Available Among the irrigation systems used today, trickle irrigation is one of the most efficient methods. This research, conducted by means of field tests, had the objective of comparing head loss evolution on water filtration with a disc filter (130 mum and a non-woven synthetic fabric filter used in a drip irrigation system. The test consisted of fertirrigation with organic fertilizer, and chemical treatment of the water with sodium hypochlorite. Physical, chemical, and biological parameters were analyzed, such as: pH, turbidity, suspended solids, dissolved solids, EC, hardness, Langelier index, total iron, manganese, sulfides, algae, and bacteria. The water source used in this experiment was from an open reservoir, where an experimental trickle irrigation system had been installed. The research was developed in four steps lasting 30 days each, during different seasons. The chemical factors pH, total iron, and concentration of sulfides presented a medium risk of clogging the emitters. All other physical and biological water quality parameters analyzed resulted in values that did not present an emitter-clogging risk. There was a correlation of results between physical parameters turbidity, suspended solids, and algae, and suspended solids. Fertirrigation influenced water quality. The concentration of free chlorine was higher in the effluent from the disc filter. Head loss evolution in the non-woven synthetic fabric filter was more striking and faster than in the disc filter.Dentre os sistemas de irrigação atualmente utilizados, a irrigação por gotejamento é um dos métodos mais eficientes. Este trabalho teve como objetivo fazer uma investigação experimental para comparar a evolução da perda de carga dos meios filtrantes disco (130 mim e manta sintética não tecida na filtragem da água, utilizados em um sistema de irrigação por gotejamento. Nesta comparação utilizou-se a técnica da fertirrigação com fertilizante orgânico e um

  19. Bag filters

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, M; Komeda, I; Takizaki, K

    1982-01-01

    Bag filters are widely used throughout the cement industry for recovering raw materials and products and for improving the environment. Their general mechanism, performance and advantages are shown in a classification table, and there are comparisons and explanations. The outer and inner sectional construction of the Shinto ultra-jet collector for pulverized coal is illustrated and there are detailed descriptions of dust cloud prevention, of measures used against possible sources of ignition, of oxygen supply and of other topics. Finally, explanations are given of matters that require careful and comprehensive study when selecting equipment.

  20. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  1. Filtration and retention capacities of filter aids

    International Nuclear Information System (INIS)

    Mellah, A.; Boualia, A.

    1992-01-01

    The present work involves the filtration of impure uranyl nitrate solutions by different filter aids such as kieselguhr, celite and bleaching clay. The retention of substances contained in uranyl nitrate solution was determined using the three filter aids. A study of the effects of granulometry and filter earths treatment (thermal and chemical) on the filtration rate was performed

  2. Studies on denitrification performance of tricking filters

    International Nuclear Information System (INIS)

    Ruediger, A.

    1993-01-01

    Trickling filters are one of the oldest methods of biological waste water purification, widely used ever since they were first developed. These filters are mostly used for aerobic purification of water as highly polluted or lightly polluted reactors. While these systems are very useful for the elemination of organic pollution and the nitrification of the waste waters, denitrification of the whole plant poses considerable problems. The question is in how far trickling filters can be used as denitrification reactors. The conditions of successful denitrification in trickling filters is investigated, denitrification performance is established. Studies were conducted in laboratory, semi-industrial and industrial scale. (BBR) [de

  3. Problems of reliability and economy work of thermal power plants water treatment based on baromembrane technologies

    Science.gov (United States)

    Chichirova, N. D.; Chichirov, A. A.; Saitov, S. R.

    2017-11-01

    The introduction of baromembrane water treatment technologies for water desalination at Russian thermal power plants was beganed more than 25 years ago. These technologies have demonstrated their definite advantage over the traditional technologies of additional water treatment for steam boilers. However, there are problems associated with the reliability and economy of their work. The first problem is a large volume of waste water (up to 60% of the initial water). The second problem a expensive and unique chemical reagents complex (biocides, antiscalants, washing compositions) is required for units stable and troublefree operation. Each manufacturer develops his own chemical composition for a certain membrane type. This leads to a significant increase in reagents cost, as well as creates dependence of the technology consumer on the certain supplier. The third problem is that the reliability of the baromembrane units depends directly on the water preliminary treatment. The popular pre-cleaning technology with coagulation of aluminum oxychloride proves to be unacceptable during seasonal changes in the quality of the source water at a number of stations. As a result, pollution, poisoning and lesion of the membrane structure or deterioration of their mechanical properties are observed. The report presents ways to solve these problems.

  4. Process for washing electromagnetic filters

    International Nuclear Information System (INIS)

    Guittet, Maurice; Treille, Pierre.

    1980-01-01

    This process concerns the washing of an electro-magnetic filter used, inter alia, for filtering the drain-off waters of nuclear power station steam generators, by means of a washing water used in closed circuit and freed, after each cleaning, of the solids in suspension it contains, by settlement of these solids. This invention enables the volume of water to be evaporated to be divided by 50, thereby providing a solid assurance of better safety, apart from a very significant saving [fr

  5. Co-selection of antibiotic resistance via copper shock loading on bacteria from a drinking water bio-filter.

    Science.gov (United States)

    Zhang, Menglu; Chen, Lihua; Ye, Chengsong; Yu, Xin

    2018-02-01

    Heavy metal contamination of source water frequently occurred in developing countries as a result of accidents. To address the problems, most of the previous studies have focused on engineering countermeasures. In this study, we investigated the effects of heavy metals, particularly copper, on the development of antibiotic resistance by establishing a copper shock loading test. Results revealed that co-selection occurred rapidly within 6 h. Copper, at the levels of 10 and 100 mg/L, significantly increased bacterial resistance to the antibiotics tested, including rifampin, erythromycin, kanamycin, and a few others. A total of 117 antimicrobial-resistance genes were detected from 12 types of genes, and the relative abundance of most genes (particularly mobile genetic elements intⅠand transposons) was markedly enriched by at least one fold. Furthermore, the copper shock loading altered the bacterial community. Numerous heavy metal and antibiotic resistant strains were screened out and enriched. These strains are expected to enhance the overall level of resistance. More noticeably, the majority of the co-selected antibiotic resistance could sustain for at least 20 h in the absence of copper and antimicrobial drugs. Resistance to vancomycin, erythromycin and lincomycin even could remain for 7 days. The prominent selection pressure by the copper shock loading implies that a real accident most likely poses similar impacts on the water environment. An accidental release of heavy metals would not only cause harm to the ecological environment, but also contribute to the development of bacterial antibiotic resistance. Broader concerns should be raised about the biological risks caused by sudden releases of pollutants by accidents. Copyright © 2017. Published by Elsevier Ltd.

  6. Determination of steroid hormones and related compounds in filtered and unfiltered water by solid-phase extraction, derivatization, and gas chromatography with tandem mass spectrometry

    Science.gov (United States)

    Foreman, William T.; Gray, James L.; ReVello, Rhiannon C.; Lindley, Chris E.; Losche, Scott A.; Barber, Larry B.

    2012-01-01

    A new analytical method has been developed and implemented at the U.S. Geological Survey National Water Quality Laboratory that determines a suite of 20 steroid hormones and related compounds in filtered water (using laboratory schedule 2434) and in unfiltered water (using laboratory schedule 4434). This report documents the procedures and initial performance data for the method and provides guidance on application of the method and considerations of data quality in relation to data interpretation. The analytical method determines 6 natural and 3 synthetic estrogen compounds, 6 natural androgens, 1 natural and 1 synthetic progestin compound, and 2 sterols: cholesterol and 3--coprostanol. These two sterols have limited biological activity but typically are abundant in wastewater effluents and serve as useful tracers. Bisphenol A, an industrial chemical used primarily to produce polycarbonate plastic and epoxy resins and that has been shown to have estrogenic activity, also is determined by the method. A technique referred to as isotope-dilution quantification is used to improve quantitative accuracy by accounting for sample-specific procedural losses in the determined analyte concentration. Briefly, deuterium- or carbon-13-labeled isotope-dilution standards (IDSs), all of which are direct or chemically similar isotopic analogs of the method analytes, are added to all environmental and quality-control and quality-assurance samples before extraction. Method analytes and IDS compounds are isolated from filtered or unfiltered water by solid-phase extraction onto an octadecylsilyl disk, overlain with a graded glass-fiber filter to facilitate extraction of unfiltered sample matrices. The disks are eluted with methanol, and the extract is evaporated to dryness, reconstituted in solvent, passed through a Florisil solid-phase extraction column to remove polar organic interferences, and again evaporated to dryness in a reaction vial. The method compounds are reacted with

  7. Transport of water in proximal kidney tubules from whole tubules to single channels: length and section of the selectivity filter of aquaporin-1.

    Science.gov (United States)

    Whittembury, G; González, E; Hernández, C S; Gutiérrez, A M; Echevarría, M

    1997-06-27

    Proximal straight tubule (PST) were dissected from rabbit kidneys, held with crimping pipettes in a chamber bathed in a buffered mannitol isosmotic solution (MBS, 295 mOsm/kg). Tubule cell volume changes with time (dV/Adt) after steps in MBS osmolality (delta Cs) were monitored on line with an inverted microscope, a TV camera and an image processor. Reflection coefficients sigma and osmotic permeability coefficients, Pos, for several solutes were measured using two methods. Method 1: sigma was calculated from the delta Csiso of impermeant and permeant solutes at which (dV/Adt)t-->0 = 0 (i.e., by a null point method). It is denoted as sigma 1. sigma 1 = 1.00 for mannitol (M), raffinose (R), sucrose (S), glycerol (G), acetamide (A) and urea (U). With formamide (F), sigma 1, Formamide = 0.62 +/- 0.05. These findings confirm our previous value of dp = 4.5 A for the diameter of the selectivity filter of the basolateral PST cell membrane water channel AQP1. Method 2: PST were exposed for 20 s to MBS made hyperosmotic by addition of a delta Cs of 35 mOsm/kg of R, S, M, G, A and U. Cells shrunk within 500 ms of t = 0 to their osmometric volume and remained shrunk for the 20 s of the osmotic challenge. Pos was measured from the shrinking curves. P(os) = 3000 +/- 25 microns/s with R, S, M, G, A and U. Method 2 also allowed to calculate sigma, denoted as sigma 2. sigma 2 = 1.00 for R, S, M, G, A and U. By contrast, the shrinking curve produced by a delta Cs of 35 mOsm/kg F was 1/5th to 1/6th slower and smaller (i.e., subosmometric) than that produced by a delta Cs of 35 mOsm/kg R, S, M, G, A and U. Furthermore, with F cells did not remain shrunk but recovered their original volume within 3 s. P(os) (measured with F) is denoted as P(os)*, P(os)* = 480 +/- 30 microns/s. sigma 2, Formamide = 0.16 +/- 0.01. Use of sigma 1, sigma 2 and P(os)* values in Hill's equations for the bimodal theory of osmosis leads to n = 2-9. Where n is the number of water molecules single filling

  8. The Planck-Benzinger thermal work function in the condensation of water vapor

    Science.gov (United States)

    Chun, Paul W.

    Based on the Planck-Benzinger thermal work function using Chun's method, the innate temperature-invariant enthalpy at 0 K, ?H0(T0), for the condensation of water vapor as well as the dimer, trimer, tetramer, and pentamer form in the vapor phase, was determined to be 0.447 kcal mol-1 for vapor, 1.127 for the dimer, 0.555 for the trimer, 0.236 for the tetramer, and 0.079 kcal mol-1 for the pentamer using ?G(T) data reported by Kell et al. in 1968 and Kell and McLaurin in 1969. These results suggest that the predominant dimeric form is the most stable of these n-mers. Using Nemethy and Scheraga's 1962 data for the Helmholtz free energy of liquid water, the value of ?H0(T0) was determined to be 1.21 kcal mol-1. This is very close to the value for the energy of the hydrogen bond EH of 1.32 kcal mol-1 reported by Nemethy and Scheraga, using statistical thermodynamics. It seems clear that very little energy is required for interconversion between the hypothetical supercooled water vapor and glassy water at 0 K. A hypothetical supercooled water vapor at 0 K is apparently almost as highly associated as glassy water at that temperature, suggesting a dynamic equilibrium between vapor and liquid. This water vapor condensation is highly similar in its thermodynamic behavior to that of sequence-specific pairwise (dipeptide) hydrophobic interaction, except that the negative Gibbs free energy change minimum at ?Ts?, the thermal setpoint for vapor condensation, where T?S = 0, occurs at a considerably lower temperature, 270 K (below 0°C) compared with ?350 K. The temperature of condensation ?Tcond? at which ?G(T) = 0, where water vapor begins to condense, was found to be 383 K. In the case of a sequence-specific pairwise hydrophobic interaction, the melting temperature, ?Tm?, where ?G(Tm) = 0 was found to be 460 K. Only between two temperature limits, ?Th? = 99 K and ?Tcond? = 383 K, where ?G(Tcond) = 0, is the net chemical driving force favorable for polymorphism of glassy water

  9. DETECCIÓN DE PÉRDIDAS EN TUBERÍAS DE AGUA: PROPUESTA BASADA EN UN BANCO DE FILTROS LEAK DETECTION IN WATER PIPELINES: PROPOSAL BASED ON A BANK OF FILTERS

    Directory of Open Access Journals (Sweden)

    Lucía Castro Burgos

    2009-12-01

    Full Text Available Actualmente la detección de pérdidas (DP en tuberías de agua es un área de investigación activa, y con un creciente interés, debido a la importancia del transporte seguro del vital elemento. Este trabajo considera el problema de DP en tuberías de agua por medio de redundancia analítica, basada en un modelo matemático y utilizando técnicas de estimación de estados, teniendo por objetivo principal estudiar, proponer, implementar y aplicar algoritmos eficientes que permitan abordar de manera general el problema de DP. Para lograr esto se propone y evalúa un banco de filtros, implementados con filtros de Kalman (FK y filtros de partículas (FP. Con esto se busca contribuir conceptualmente a la formulación del problema de DP, de manera modular, permitiendo que en un estudio futuro otras técnicas puedan ser utilizadas para resolver el problema. Además, obtener algoritmos eficientes y confiables, basados en un estimador de estados capaces de responder a requerimientos industriales, tales como: entregar, a partir de medidas de entrada y salida disponibles, una estimación fiable del estado del proceso, esto con independencia de la dinámica lineal o no lineal, asimismo, ser de fácil manejo y fácil configuración. La simulación computacional y los resultados experimentales muestran la efectividad de combinar FP con FK, para el caso básico de dos pérdidas secuenciales en una tubería, presentando ventajas de rápida convergencia y reducción del error de estimación, factores importantes en el problema de DP en ductos hídricos.Currently leak detection (LD in water pipelines is an active area of research that is attracting increasing interest due to the importance of the safe transport of this vital resource. This work considers the problem of LD in water pipes by means of analytical redundancy, based on a mathematical model and using state estimation techniques. The main aim of this work is to research, propose, implement and apply

  10. Estimation of pressure drop in the mixing zone of beds in operation filters as drinking water treatment by a mathematical model; Estimacion de la perdida de carga en la zona de mezcla mediante una ecuacion matematica en filtros pilotos para el tratamiento del agua potable

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Miranda, J. P.

    2010-07-01

    This paper describes the correlation of a mathematical model that considers the pressure drop (energy) in the mixing zone of beds in operation filters as drinking water treatment, filters applied in conventional pilot operated and mounted on a water treatment plant of a municipally in Colombia. (Author) 20 refs.

  11. Experimental Investigation to Heat Transfer Augmentation in A Car Radiator Worked with (Water - Magnesium Oxide) Nanofluid.

    OpenAIRE

    Hameed K. Hamzah; Qusay Rasheed Al-Amir

    2017-01-01

    In this work, effect of adding MgO nanoparticle to base fluid (water) in car radiator has been implemented experimentally. In this investigation, an experimental test rig has been designed to study effect inlet temperature of nanofluid, the flow rate and nanoparticle volume fraction on heat transfer rates. Six different concentrations of nanofluid of 0.125%, 0.25%, 0.5%,1% ,1.5% and 2% have been prepared by mixed of MgO nanoparticles with water. Reynolds number of nanofluid was between 4500 a...

  12. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  13. A biological oil adsorption filter

    International Nuclear Information System (INIS)

    Pasila, A.

    2005-01-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  14. In Situ Cleanable Alternative HEPA Filter Media

    International Nuclear Information System (INIS)

    Adamson, D. J.; Terry, M. T.

    2002-01-01

    Energy's Hazardous Facilities'', found that conventional glass fiber HEPA filters are structurally weak and easily damaged by water or fire. The structurally stronger sintered metal and ceramic filters would reduce the potential of a catastrophic HEPA filter failure due to filter media breakthrough in the process ventilation system. An in situ regenerable system may also find application in recovering nuclear materials, such as plutonium, collected on glove box exhaust HEPA filters. This innovative approach of the in situ regenerative filtration system may be a significant improvement upon the shortfalls of conventional disposable HEPA filters

  15. Influence of water-filtered infrared-A (wIRA on reduction of local fat and body weight by physical exercise

    Directory of Open Access Journals (Sweden)

    Schmitz, Gerd

    2006-07-01

    Full Text Available Aim of the study: Investigation, whether water-filtered infrared-A (wIRA irradiation during moderate bicycle ergometer endurance exercise has effects especially on local fat reduction and on weight reduction beyond the effects of ergometer exercise alone. Methods: Randomised controlled study with 40 obese females (BMI 30-40 (median: 34.5, body weight 76-125 (median: 94.9 kg, age 20-40 (median: 35.5 years, isocaloric nutrition, 20 in the wIRA group and 20 in the control group. In both groups each participant performed 3 times per week over 4 weeks for 45 minutes bicycle ergometer endurance exercise with a constant load according to a lactate level of 2 mmol/l (aerobic endurance load, as determined before the intervention period. In the wIRA group in addition large parts of the body (including waist, hip, and thighs were irradiated during all ergometries of the intervention period with visible light and a predominant part of water-filtered infrared-A (wIRA, using the irradiation unit “Hydrosun® 6000” with 10 wIRA radiators (Hydrosun® Medizintechnik, Müllheim, Germany, radiator type 500, 4 mm water cuvette, yellow filter, water-filtered spectrum 500-1400 nm around a speed independent bicycle ergometer. Main variable of interest: change of “the sum of circumferences of waist, hip, and both thighs of each patient” over the intervention period (4 weeks. Additional variables of interest: body weight, body mass index BMI, body fat percentage, fat mass, fat-free mass, water mass (analysis of body composition by tetrapolar bioimpedance analysis, assessment of an arteriosclerotic risk profile by blood investigation of variables of lipid metabolism (cholesterol, triglycerides, high density lipoproteins HDL, low density lipoproteins LDL, apolipoprotein A1, apolipoprotein B, clinical chemistry (fasting glucose, alanin-aminotransferase ALT (= glutamyl pyruvic transaminase GPT, gamma-glutamyl-transferase GGT, creatinine, albumin, endocrinology

  16. Filter Effectiveness Evaluation

    Science.gov (United States)

    2013-08-01

    synthetic paraffinic kerosene (SPK), as well as Ultra Low Sulfur Diesel (ULSD) treated with mono-olein to simulate the effects of biodiesel . Results...fuel. Sufficient analysis and qualification of filter products is becoming increasingly crucial in ground transportation vehicles to promote the...well as a simulated biodiesel composed of ultra low sulfur diesel (ULSD) and mono-olein. As written in the scope of work, the alternative aviation

  17. Public-Private Partnerships Working Beyond Scale Challenges toward Water Quality Improvements from Private Lands

    Science.gov (United States)

    Enloe, Stephanie K.; Schulte, Lisa A.; Tyndall, John C.

    2017-10-01

    In recognition that Iowa agriculture must maintain long-term production of food, fiber, clean water, healthy soil, and robust rural economies, Iowa recently devised a nutrient reduction strategy to set objectives for water quality improvements. To demonstrate how watershed programs and farmers can reduce nutrient and sediment pollution in Iowa waters, the Iowa Water Quality Initiative selected the Boone River Watershed Nutrient Management Initiative as one of eight demonstration projects. For over a decade, diverse public, private, and non-profit partner organizations have worked in the Boone River Watershed to engage farmers in water quality management efforts. To evaluate social dynamics in the Boone River Watershed and provide partners with actionable recommendations, we conducted and analyzed semi-structured interviews with 33 program leaders, farmers, and local agronomists. We triangulated primary interview data with formal analysis of Boone River Watershed documents such as grant applications, progress reports, and outreach materials. Our evaluation suggests that while multi-stakeholder collaboration has enabled partners to overcome many of the traditional barriers to watershed programming, scale mismatches caused by external socio-economic and ecological forces still present substantial obstacles to programmatic resilience. Public funding restrictions and timeframes, for example, often cause interruptions to adaptive management of water quality monitoring and farmer engagement. We present our findings within a resilience framework to demonstrate how multi-stakeholder collaboration can help sustain adaptive watershed programs to improve socio-ecological function in agricultural watersheds such as the Boone River Watershed.

  18. Organic contamination of ground water at Gas Works Park, Seattle, Washington

    International Nuclear Information System (INIS)

    Turney, G.L.; Goerlitz, D.F.

    1990-01-01

    Gas Works Park, in Seattle, Washington, is located on the site of a coal and oil gasification plant that ceased operation in 1956. During operation, many types of wastes, including coal, tar, and oil, accumulated on-site. The park soil is currently (1986) contaminated with compounds such as polynuclear aromatic hydrocarbons, volatile organic compounds, trace metals, and cyanide. Analyses of water samples from a network of observation wells in the park indicate that these compounds are also present in the ground water. Polynuclear aromatic hydrocarbons and volatile organic compounds were identified in ground water samples in concentrations as large as 200 mg/L. Concentrations of organic compounds were largest where ground water was in contact with a non-aqueous phase liquid in the soil. Where no non-aqueous phase liquid was present, concentrations were much smaller, even if the ground water was in contact with contaminated soils. This condition is attributed to weathering processes in which soluble, low-molecular-weight organic compounds are preferentially dissolved from the non-aqueous phase liquid into the ground water. Where no non-aqueous phase liquid is present, only stained soils containing relatively insoluble, high-molecular-weight compounds remain. Concentrations of organic contaminants in the soils may still remain large

  19. Organic contamination of ground water at Gas Works Park, Seattle, Washington

    Science.gov (United States)

    Turney, G.L.; Goerlitz, D.F.

    1990-01-01

    Gas Works Park, in Seattle, Washington, is located on the site of a coal and oil gasification plant that ceased operation in 1956. During operation, many types of wastes, including coal, tar, and oil, accumulated on-site. The park soil is currently (1986) contaminated with compounds such as polynuclear aromatic hydrocarbons, volatile organic compounds, trace metals, and cyanide. Analyses of water samples from a network of observation wells in the park indicate that these compounds are also present in the ground water. Polynuclear aromatic hydrocarbons and volatile organic compounds were identified in ground water samples in concentrations as large as 200 mg/L. Concentrations of organic compounds were largest where ground water was in contact with a non-aqueous phase liquid in the soil. Where no non-aqueous phase liquid was present, concentrations were much smaller, even if the ground water was in contact with contaminated soils. This condition is attributed to weathering processes in which soluble, low-molecular-weight organic compounds are preferentially dissolved from the non-aqueous phase liquid into the ground water. Where no non-aqueous phase liquid is present, only stained soils containing relatively insoluble, high-molecular-weight compounds remain. Concentrations of organic contaminants in the soils may still remain large.

  20. Projects on filter testing in Sweden

    International Nuclear Information System (INIS)

    Normann, B.; Wiktorsson, C.

    1985-01-01

    The Swedish nuclear power program comprises twelve light water reactors. Nine are boiling water reactors of ASEA-ATOM design and three are pressurized water reactors of Westinghouse design. Of these, ten are in operation and two are under construction and planned to go into operation during late 1984 and early 1985, respectively. Frequent tests on the penetration of particles through HEPA filters, regular tests on the adsorption of methyl iodide in the stand-by carbon filter units by laboratory testing are discussed. The proposed new regulations are based on many years of experience of filter system operation and of tests in-situ and in the laboratory. Moisture and water are factors that affect the functioning of filters. In addition, high loading of dust can give rise to increased penetration through HEPA filters, however pinholes could have less influence on the total penetration. Laboratory tests show that DOP particles retain 30-40% in 90 mm carbon filters (8-12 mesh). However no effect on the ability of carbon to adsorb methyl iodide after DOP contamination in combined carbon/HEPA filters has been observed. Leakage from ventilation ducts can cause radioactive contamination problems during filter testing with radioiodine. In-situ testing of control-room filters has been performed using inactive methyl iodide. A type of carbon bed not previously used in Sweden has been introduced. Testing of this filter type is discussed

  1. Selected solutions and design features from the design of remotely handled filters and the technology of remote filter handling. Previous operating experience with these components in the PASSAT facility

    International Nuclear Information System (INIS)

    Jannakos, K.; Lange, W.; Potgeter, G.; Furrer, J.; Wilhelm, J.G.

    1981-01-01

    In a prototype filter offgas cleaning system for reprocessing plants (PASSAT) built at the Karlsruhe Nuclear Research Center a fullscale filter cell with remotely handled filters for aerosol and iodine removal and the corresponding remote handling systems for exchange, bagging out, packaging and disposal of spent filter elements has been installed and run in trial operation since July 1978. The filters and the replacement techniques have been tested for the past two years or so and so far have always worked satisfactory over the test period involving some 150 replacement events. Neither wear nor corrosion phenomena were found in the filter housings and the replacement systems. The seals and clamping devices were selected so that during operation the prescribed leak rates of -3 Torr l/s were always maintained on the filter lid, the seat of the filter element and the cell lock. The total clamping loads for the filter element and the filter lid amount to approx. 20 kN. The force necessary to separate the filter element from the filter housing is approx. 3.5 kN. No ruptures of seals or gaskets were to be detected. The design of the filters and of the handling systems has been found satisfactorily in the cold test operation so far and can be recommended for use in nuclear facilities. In all experiments conducted until now PASSAT has worked without any failure. All operating data required in the specifications were met in the test period. The maximum pressure loss in the system with loaded filter elements amounts to some 3000 mm of water. After operation with iodine and NO/sub x/, plant components exposed to 100% relative humidity and condensate showed corrosion

  2. Implicit LES using adaptive filtering

    Science.gov (United States)

    Sun, Guangrui; Domaradzki, Julian A.

    2018-04-01

    In implicit large eddy simulations (ILES) numerical dissipation prevents buildup of small scale energy in a manner similar to the explicit subgrid scale (SGS) models. If spectral methods are used the numerical dissipation is negligible but it can be introduced by applying a low-pass filter in the physical space, resulting in an effective ILES. In the present work we provide a comprehensive analysis of the numerical dissipation produced by different filtering operations in a turbulent channel flow simulated using a non-dissipative, pseudo-spectral Navier-Stokes solver. The amount of numerical dissipation imparted by filtering can be easily adjusted by changing how often a filter is applied. We show that when the additional numerical dissipation is close to the subgrid-scale (SGS) dissipation of an explicit LES the overall accuracy of ILES is also comparable, indicating that periodic filtering can replace explicit SGS models. A new method is proposed, which does not require any prior knowledge of a flow, to determine the filtering period adaptively. Once an optimal filtering period is found, the accuracy of ILES is significantly improved at low implementation complexity and computational cost. The method is general, performing well for different Reynolds numbers, grid resolutions, and filter shapes.

  3. Filters for radioactive liquid wastes

    International Nuclear Information System (INIS)

    Koshiba, Yukihiko; Kawashima, Akio

    1980-01-01

    In the crud generated in the reactor cooling water for nuclear power plants, iron oxides (hematite and magnetite) are contained as the main components, and also Co, Mn, Fe, Cr exist as radioactive nuclides. A new filter to separate these cruds, nuclepore membrane filter (NPMF), was investigated for its adaptability, and has been adopted as a practical filter for radioactive liquid wastes. The NPMF has such features as the possibility of complete automation of operation, no generation of secondary wastes, and easy maintenance, because the NPMF has uniform circular holes in poly-carbonate thin films, and shows the properties of stable filtering of particulates, capability of back washing, and others. The elements mounted in a practical system have such construction that the membrane is cut in the form of doughnut, and sandwiched with 100 mesh polyester nets (spacer); the obtained unit filter (cassette) is mounted on the stackable plate of the same size; and 80 pieces of this cassette are formed in a filter of 4 m 2 filtering area. The performance varies with the properties of suspended matters and the turbidity of wastes. For example, the filtered liquid of 0.1 ppm or less can be obtained when the 1 μm filter material is used to treat the liquid waste containing 1 to 100 ppm suspended matters. Usually back washed water is produced by about 1/100 of treated liquid wastes. The lifetime of the membrane is expected to be 1 or 2 years if crud is the main component. (Wakatsuki, Y.)

  4. Biodegradation behavior of natural organic matter (NOM) in a biological aerated filter (BAF) as a pretreatment for ultrafiltration (UF) of river water

    KAUST Repository

    Huang, Guocheng

    2011-04-15

    In this study, biodegradation of natural organic matter (NOM) in a biological aerated filter (BAF) as pretreatment of UF treating river water was investigated. Photometric measurement, three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy and liquid chromatography with online organic carbon detector (LC-OCD) were used to investigate the fate of NOM fractions in the BAF+UF process. Results showed that the BAF process could effectively remove particles and parts of dissolved organic matter, which led to a lower NOM loading in the UF system, but different NOM fractions showed different biodegradation potentials. Further biodegradation batch experiments confirmed this observation and identified that polysaccharides and proteins (quantified using photometric methods) contained a large proportion of readily biodegradable matter while humic substances were mainly composed of inert organic substances. According to EEM measurements, it is evident that protein-like substances were more readily eliminated by microorganisms than humic-like substances. LC-OCD data also supported the phenomena that the polysaccharides and large-size proteins were more degradable than humic substances. © 2011 Springer-Verlag.

  5. Bibliography of work on the photocatalytic removal of hazardous compounds from water and air

    Energy Technology Data Exchange (ETDEWEB)

    Blake, D.M.

    1994-05-01

    This is a bibliography of information in the open literature on work that has been done to date on the photocatalytic oxidation of compounds, principally organic compounds. The goal of the listing is removing hazardous oompounds from water or air. It contains lists of substances and literature citations. The bibliography includes information obtained through the middle of 1993 and some selected references for the balance of that year.

  6. Performance Characteristics of Hero's Turbine Using Hot Water as a Working Fluid

    OpenAIRE

    藤井, 照重; 太田, 淳一; 赤川, 浩爾; 中村, 登志; 浅野, 等

    1990-01-01

    From the view point of energy saving and the development of new energy resources,it is important to utilize geothermal resources and waste heat from factories. As one of the energy conversion expanders,there is a radial outflow reaction turbine(that is,Hero's turbine). Performance characteristics of Hero's turbine using subcooled hot water as a working fluid are clarified analytically and experimentally. It is found that:(a)there is an optimum rotational speed at which maximum turbine efficie...

  7. On the Acoustic Filtering of the Pipe and Sensor in a Buried Plastic Water Pipe and its Effect on Leak Detection: An Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Fabrício Almeida

    2014-03-01

    Full Text Available Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors.

  8. Gravimetric and dilatometric research of elements action on three dimensional filter by themal effects

    Directory of Open Access Journals (Sweden)

    B. K. Shayakhmetov

    2014-01-01

    Full Text Available In the work there are presented the results of studying the filtering elements weight changes when heated. For all the variants of filtering elements at the primary stages of heating there is characteristic increasing their linear dimensions due to their thermal expansion. It was established that using hydrolyzed ethyl silicate as a binder, as well as water solution of liquid glass with addition of aluminum powder in the refractory material permits to obtain filtering elements without high-temperature solid-phase sintering.

  9. Earthquake countermeasure work on water intake structure based on post-construction shear reinforcement method

    International Nuclear Information System (INIS)

    Satou, Yoshihito; Wani, Masaaki; Wachi, Takamitsu

    2017-01-01

    Hamaoka Nuclear Power Station set up 'earthquake motion as the base for remodeling work' by referring to the strong earthquake fault model assumed by the 'Study meeting for Nankai Trough's mega thrust earthquake model' of the Cabinet Office. Based on this earthquake, it implemented seismic countermeasure work using ceramic fixing type post-construction shear reinforcement bars by targeting the Unit 4 water intake tank screen room. This construction work was carried out in a short period of about nine months due to a restriction in the drainage period of the water intake tank. Thanks to the improvement of process control, such as adoption of a two-shift (day and night) system, this work was completed. On the other hand, the quality of construction was secured by adopting a drilling machine with a resistance sensor at the time of drilling and plastic grout at the time of grout filling, as well as through quality inspection based on Construction Technology Review and Certification. (A.O.)

  10. Studies of water-in-oil emulsions : energy and work threshold as a function of temperature

    International Nuclear Information System (INIS)

    Fingas, M.; Fieldhouse, B.; Lerouge, L.

    2001-01-01

    A study was conducted in which the effect of temperature on the kinetics and stability of water-in-oil formation was examined. Previous studies have shown that viscosity influences the formation and stability of water in oil emulsions, therefore a viscosity window has been postulated as necessary for the formation of stable emulsions. The temperature dependence of this physical property is examined through a study of 3 oils, Green Canyon, Arabian Light and Point Arguello. The oils were subjected to mixing at 5, 15 and 25 degrees C. Both Arabian Light and Point Arguello formed meso-stable emulsions at 15 degrees C and were examined further. Arabian Light had a relatively high viscosity, while Point Arguello had a low viscosity. The objective was to examine the effects of changing viscosity resulting from changes in temperature on oil at either end of the observed viscosity window. The total energy applied to the oil/water in the emulsion formation apparatus was varied from about 50 to 600,000 ergs. Work was varied from 1 to 5123 Joules per second. It was determined that a minimum energy threshold is needed for most emulsion formation, but only work correlates with the stability value. The emulsions formed at lower temperatures exhibited higher stability than would be expected from the increase in viscosity. This is most likely because the increase was insufficient, in the case of Green Canyon oil, to result in the formation of emulsions. It was concluded that the stability of an emulsion formed from a given oil increases with decreasing formation temperature. The apparent viscosity is higher at the lower temperature. The work was found to correlate most closely with the stability of the emulsion or water-in-oil state. 7 refs., 4 tabs., 6 figs

  11. Stress corrosion cracking behavior of annealed and cold worked 316L stainless steel in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Sáez-Maderuelo, A., E-mail: alberto.saez@ciemat.es; Gómez-Briceño, D.

    2016-10-15

    Highlights: • The alloy 316L is susceptible to stress corrosion cracking in supercritical water. • The susceptibility of alloy 316L increases with temperature and plastic deformation. • Dynamic strain ageing processes may be active in the material. - Abstract: The supercritical water reactor (SCWR) is one of the more promising designs considered by the Generation IV International Forum due to its high thermal efficiency and improving security. To build this reactor, standardized structural materials used in light water reactors (LWR), like austenitic stainless steels, have been proposed. These kind of materials have shown an optimum behavior to stress corrosion cracking (SCC) under LWR conditions except when they are cold worked. It is known that physicochemical properties of water change sharply with pressure and temperature inside of the supercritical region. Owing to this situation, there are several doubts about the behavior of candidate materials like austenitic stainless steel 316L to SCC in the SCWR conditions. In this work, alloy 316L was studied in deaerated SCW at two different temperatures (400 °C and 500 °C) and at 25 MPa in order to determine how changes in this variable influence the resistance of this material to SCC. The influence of plastic deformation in the behavior of alloy 316L to SCC in SCW was also studied at both temperatures. Results obtained from these tests have shown that alloy 316L is susceptible to SCC in supercritical water reactor conditions where the susceptibility of this alloy increases with temperature. Moreover, prior plastic deformation of 316L SS increased its susceptibility to environmental cracking in SCW.

  12. Multilevel particle filter

    KAUST Repository

    Law, Kody

    2016-01-06

    This talk will pertain to the filtering of partially observed diffusions, with discrete-time observations. It is assumed that only biased approximations of the diffusion can be obtained, for choice of an accuracy parameter indexed by l. A multilevel estimator is proposed, consisting of a telescopic sum of increment estimators associated to the successive levels. The work associated to O( 2) mean-square error between the multilevel estimator and average with respect to the filtering distribution is shown to scale optimally, for example as O( 2) for optimal rates of convergence of the underlying diffusion approximation. The method is illustrated on some toy examples as well as estimation of interest rate based on real S&P 500 stock price data.

  13. Determination of Human-Health Pharmaceuticals in Filtered Water by Chemically Modified Styrene-Divinylbenzene Resin-Based Solid-Phase Extraction and High-Performance Liquid Chromatography/Mass Spectrometry

    Science.gov (United States)

    Furlong, Edward T.; Werner, Stephen L.; Anderson, Bruce D.; Cahill, Jeffery D.

    2008-01-01

    In 1999, the Methods Research and Development Program of the U.S. Geological Survey National Water Quality Laboratory began the process of developing a method designed to identify and quantify human-health pharmaceuticals in four filtered water-sample types: reagent water, ground water, surface water minimally affected by human contributions, and surface water that contains a substantial fraction of treated wastewater. Compounds derived from human pharmaceutical and personal-care product use, which enter the environment through wastewater discharge, are a newly emerging area of concern; this method was intended to fulfill the need for a highly sensitive and highly selective means to identify and quantify 14 commonly used human pharmaceuticals in filtered-water samples. The concentrations of 12 pharmaceuticals are reported without qualification; the concentrations of two pharmaceuticals are reported as estimates because long-term reagent-spike sample recoveries fall below acceptance criteria for reporting concentrations without qualification. The method uses a chemically modified styrene-divinylbenzene resin-based solid-phase extraction (SPE) cartridge for analyte isolation and concentration. For analyte detection and quantitation, an instrumental method was developed that used a high-performance liquid chromatography/mass spectrometry (HPLC/MS) system to separate the pharmaceuticals of interest from each other and coextracted material. Immediately following separation, the pharmaceuticals are ionized by electrospray ionization operated in the positive mode, and the positive ions produced are detected, identified, and quantified using a quadrupole mass spectrometer. In this method, 1-liter water samples are first filtered, either in the field or in the laboratory, using a 0.7-micrometer (um) nominal pore size glass-fiber filter to remove suspended solids. The filtered samples then are passed through cleaned and conditioned SPE cartridges at a rate of about 15

  14. Ionic liquid-based single-drop microextraction followed by liquid chromatography-ultraviolet spectrophotometry detection to determine typical UV filters in surface water samples.

    Science.gov (United States)

    Vidal, Lorena; Chisvert, Alberto; Canals, Antonio; Salvador, Amparo

    2010-04-15

    A user-friendly and inexpensive ionic liquid-based single-drop microextraction (IL-SDME) procedure has been developed to preconcentrate trace amounts of six typical UV filters extensively used in cosmetic products (i.e., 2-hydroxy-4-methoxybenzophenone, isoamyl 4-methoxycinnamate, 3-(4'-methylbenzylidene)camphor, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-methoxycinnamate) from surface water samples prior to analysis by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). A two-stage multivariate optimization approach was developed by means of a Plackett-Burman design for screening and selecting the significant variables involved in the SDME procedure, which were later optimized by means of a circumscribed central composite design. The studied variables were drop volume, sample volume, agitation speed, ionic strength, extraction time and ethanol quantity. Owing to particularities, ionic liquid type and pH of the sample were optimized separately. Under optimized experimental conditions (i.e., 10 microL of 1-hexyl-3-methylimidazolium hexafluorophosphate, 20 mL of sample containing 1% (v/v) ethanol and NaCl free adjusted to pH 2, 37 min extraction time and 1300 rpm agitation speed) enrichment factors up to ca. 100-fold were obtained depending on the target analyte. The method gave good levels of repeatability with relative standard deviations varying between 2.8 and 8.8% (n=6). Limits of detection were found in the low microg L(-1) range, varying between 0.06 and 3.0 microg L(-1) depending on the target analyte. Recovery studies from different types of surface water samples collected during the winter period, which were analysed and confirmed free of all target analytes, ranged between 92 and 115%, showing that the matrix had a negligible effect upon extraction. Finally, the proposed method was applied to the analysis of different water samples (taken from two beaches, two swimming pools and a

  15. Production of porous filter elements from PEUAPM nanocomposites and silver nanoparticles; Producao de elementos filtrantes porosos a partir de nanocompositos de PEUAPM e nanoparticulas de prata

    Energy Technology Data Exchange (ETDEWEB)

    Bizzo, M.A.; Hui, W.S., E-mail: mbizzo@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Departamento de Engenharia Metalurgica e de Materiais

    2014-07-01

    The production of filter elements for water based in polymers is widespread in the market, but has an undesirable characteristic: they are not efficient and able to retain or eliminate microorganisms at all times. This paper proposes to produce nanocomposite filters with biocidal properties composed of ultra-high molecular weight polyethylene(UHMWPE) and silver nanoparticles, the UHMWPE is responsible for the uniform porous structure of the filters and the silver nanoparticles incorporated on the polymer are responsible for the biocide action. Particulate polymer that presents a different particle size curve was used for sintering the filters. Samples of filter elements obtained in this work were characterized by the techniques of X-ray diffraction, scanning electron microscopy and EDS microanalysis. The results indicated a porosity of approximately 49% in the filter, and the formation of the nanocomposite. key-words: nanocomposites, silver, UHMWPE, filter elements. (author)

  16. Experimental Investigation to Heat Transfer Augmentation in A Car Radiator Worked with (Water - Magnesium Oxide Nanofluid.

    Directory of Open Access Journals (Sweden)

    Hameed K. Hamzah

    2017-07-01

    Full Text Available In this work, effect of adding MgO nanoparticle to base fluid (water in car radiator has been implemented experimentally. In this investigation, an experimental test rig has been designed to study effect inlet temperature of nanofluid, the flow rate and nanoparticle volume fraction on heat transfer rates. Six different concentrations of nanofluid of 0.125%, 0.25%, 0.5%,1% ,1.5% and 2% have been prepared by mixed of MgO nanoparticles with water. Reynolds number of nanofluid was between 4500 and 19000.Thermal behavior of an automobile radiator worked with nanofluid has been compared with using pure water in it. So, the fluid circulating rate in radiator has been varied in the extent of the range of 1-8 L/min and fluid inlet temperature is also varied for all experimental. Results emphasized that Nusselt number increases with an increase of liquid inlet temperature, nanoparticle volume fraction and Reynolds number. As well as, the enhancement in heat transfer coefficient due to presence of nanoparticles is more than that without noanoparticles. These results can be achieved to optimize the dimension of an automobile radiator. A good agreement was seen with theoretical and experimental results with many authors

  17. Carbon nanotube filters

    Science.gov (United States)

    Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

    2004-09-01

    Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  18. EDF program on SCC initiation of cold-worked stainless steels in primary water

    Energy Technology Data Exchange (ETDEWEB)

    Huguenin, P.; Vaillant, F.; Couvant, T. [Electricite de France (EDF/RD), Site des Renardieres, 77 - Moret sur loing (France); Buisse, L. [EDF UTO, 93 - Noisy-Le-Grand (France); Huguenin, P.; Crepin, J.; Duhamel, C.; Proudhon, H. [MINES ParisTech, Centre des Materiaux, 91 - Evry (France); Ilevbare, G. [EPRI California (United States)

    2009-07-01

    A few cases of Intergranular Stress Corrosion Cracking (IGSCC) on cold-worked austenitic stainless steels in primary water have been detected in French Pressurized Water Reactors (PWRs). A previous program launched in the early 2000's identified the required conditions for SCC of cold-worked stainless steels. It was found that a high strain hardening coupled with cyclic loading favoured SCC, whereas cracking under static conditions appeared to be difficult. A propagation model was also proposed. The first available results of the present study demonstrate the strong influence of a trapezoidal cyclic loading on the creep of 304L austenitic stainless steel. While no creep was detected under a pure static loading, the creep rate was increased by a factor 102 under a trapezoidal cyclic loading. The first results of SCC initiation performed on notched specimens under a trapezoidal cyclic loading at low frequency are presented. The present study aims at developing an engineering model for IGSCC initiation of 304L, 316L and weld 308L stainless steels. The effect of the pre-straining on the SCC mechanisms is more specifically studied. Such a model will be based on (i) SCC initiation tests on notched and smooth specimens under 'trapezoidal' cyclic loading and, (ii) constant strain rate SCC initiation tests. The influence of stress level, cold-work level, strain path, surface roughness and temperature is particularly investigated. (authors)

  19. Miniaturized dielectric waveguide filters

    OpenAIRE

    Sandhu, MY; Hunter, IC

    2016-01-01

    Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

  20. Sea-water intake tower works for Hamaoka Nuclear Power Station No. 2 Plant

    International Nuclear Information System (INIS)

    Satake, Norimoto; Sugaya, Yoshinobu; Sugimoto, Tadao

    1976-01-01

    It was determined to adopt tunnel system based on the conclusion of negotiation with local people, specifically fishermen, for the sea water intake arrangement in Hamaoka Nuclear Power Station. The main factors for determining the location of the intake tower included marine conditions such as waves and littoral sand drift, and the sea-bottom topographic features and geology of tunnel route, for which field examination, hydraulic experiments and the research and investigation on the method of construction were carried out. These results in the No.2 tower installation at the point 65 m to the east of the No.1 tower. The construction of the tower is described on the manufacture and conveyance of steel caisson, land works at Omaezaki and temporary assembly works on the sea. Then the details of tower installation and the works on site are reported. Fortunately the difficult sea works have been satisfactorily completed earlier than planned, without any accident. The construction facilities utilizing a pilot tunnel seem to have made the better achievement than expected. In spite of the results, the lifting up, off-shore conveyance, and installation of the intake tower caisson, a superheavy structure of weighting up to total 2900 ton, were critical works. (Wakatsuki, Y.)

  1. Sea-water intake tower works for Hamaoka Nuclear Power Station No. 2 Plant

    Energy Technology Data Exchange (ETDEWEB)

    Sataki, N; Sugaya, Y; Sugimoto, T [Chubu Electric Power Co. Inc., Nagoya (Japan)

    1976-01-01

    It was determined to adopt tunnel system based on the conclusion of negotiation with local people, specifically fishermen, for the sea water intake arrangement in Hamaoka Nuclear Power Station. The main factors for determining the location of the intake tower included marine conditions such as waves and littoral sand drift, and the sea-bottom topographic features and geology of tunnel route, for which field examination, hydraulic experiments and the research and investigation on the method of construction were carried out. These results in the No.2 tower installation at the point 65 m to the east of the No.1 tower. The construction of the tower is described on the manufacture and conveyance of steel caisson, land works at Omaezaki and temporary assembly works on the sea. Then the details of tower installation and the works on site are reported. Fortunately the difficult sea works have been satisfactorily completed earlier than planned, without any accident. The construction facilities utilizing a pilot tunnel seem to have made the better achievement than expected. In spite of the results, the lifting up, off-shore conveyance, and installation of the intake tower caisson, a superheavy structure of weighting up to total 2900 ton, were critical works.

  2. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  3. Antimicrobial Photoinactivation Using Visible Light Plus Water-Filtered Infrared-A (VIS + wIRA Alters In Situ Oral Biofilms.

    Directory of Open Access Journals (Sweden)

    A Al-Ahmad

    Full Text Available Recently, growing attention has been paid to antimicrobial photodynamic therapy (aPDT in dentistry. Changing the microbial composition of initial and mature oral biofilm by aPDT using visible light plus water-filtered infrared-A wavelengths (VIS + wIRA has not yet been investigated. Moreover, most aPDT studies have been conducted on planktonic bacterial cultures. Therefore, in the present clinical study we cultivated initial and mature oral biofilms in six healthy volunteers for 2 hours or 3 days, respectively. The biofilms were treated with aPDT using VIS+wIRA (200 mW cm(-2, toluidine blue (TB and chlorine e6 (Ce6 for 5 minutes. Chlorhexidine treated biofilm samples served as positive controls, while untreated biofilms served as negative controls. After aPDT treatment the colony forming units (CFU of the biofilm samples were quantified, and the surviving bacteria were isolated in pure cultures and identified using MALDI-TOF, biochemical tests and 16S rDNA-sequencing. aPDT killed more than 99.9% of the initial viable bacterial count and 95% of the mature oral biofilm in situ, independent of the photosensitizer. The number of surviving bacterial species was highly reduced to 6 (TB and 4 (Ce6 in the treated initial oral biofilm compared to the 20 different species of the untreated biofilm. The proportions of surviving bacterial species were also changed after TB- and Ce6-mediated aPDT of the mature oral biofilm, resulting in a shift in the microbial composition of the treated biofilm compared to that of the control biofilm. In conclusion, aPDT using VIS + wIRA showed a remarkable potential to eradicate both initial and mature oral biofilms, and also to markedly alter the remaining biofilm. This encourages the clinical use of aPDT with VIS + wIRA for the treatment of periimplantitis and periodontitis.

  4. The search for a filter-feeding alternative for integrated shrimp aquacultures– a preliminary study with the polychaete Sabella spallanzanii for water quality improvement

    Directory of Open Access Journals (Sweden)

    Luana Granada

    2014-06-01

    Relatively to bacteriological analysis, the density of heterotrophic bacteria at 37ºC decreased substantially (Fig. 1a. The abundance of heterotrophic bacteria at 22ºC increased from T0 to T3 (Fig. 1b. This increasing density pattern of heterotrophic bacteria at 22ºC is in accordance with Stabili et al. (2010. The author stated that could be related with the effect of temperature, assessed by Pomeroy & Wiebe (2001. However, in this study no large temperature changes occur. Thus, more intensive bacteriological analyses should be done before performing any assumptions. Regarding culturable presumptive vibrios, the abundance decreased from T0 to T3 at 22 and 35ºC (Fig. 2. Regarding to E.coli, it was possible to observe a density decrease of 90% at the end of the experiment (Fig. 3. According with the decree-law n.º 236/98 of August 1st (N.º 176 – 1998, the maximum value allowable for faecal coliforms is 2000 per 100 mL, and the maximum value recommended is 100 per 100 mL. The results for E. coli stated previously are in accordance with the decree-law requirements. The use of S. spallanzanii as bioremediator of microbial pollution revealed to be efficient in a more complex culture system. The integration of this species in the culture system plays an important role since it is able to filter, accumulate and remove several bacterial groups from the water, including human potential pathogens, and thus, reduces susceptibility to disease outbreaks.

  5. The dry filter method for passive filtered venting of the containment

    International Nuclear Information System (INIS)

    Freis, Daniel; Tietsch, Wolfgang; Obenland, Ralf; Kroes, Bert; Martinsteg, Hans

    2013-01-01

    Filtered Venting is a mitigative emergency measure to protect the containment from pressure failure in case of a severe accident. Filtered vent systems which are based on the Dry Filter Method (DFM) are proven technology, work completely passive, meet all functional requirements and show excellent performance with respect to filter efficiency. With such a system the release of radioactive fission products to the environment can be effectively minimized. Short and long term land contaminations can be avoided. (orig.)

  6. To built a solar hot water heater to work the sustainability problem

    Directory of Open Access Journals (Sweden)

    Carretero Gómez, María Begoña

    2012-01-01

    Full Text Available We are commemorating the Education Decade for Sustainable Development. If we want to create positive towards our environment and its sustainable development we have to begin working</