Energy and resource utilization of deinking sludge pyrolysis

International Nuclear Information System (INIS)

Lou, Rui; Wu, Shubin; Lv, Gaojin; Yang, Qing

2012-01-01

The thermochemical conversion technique was applied in deinking sludge from the pulp and papermaking industrial to indagate the utilization of sludge biomass to energy, and the pyrolysis characteristics and pyrolytic products of deinking sludge were studied with thermogravimetric analysis (TGA) and pyrolysis coupled with gas chromatograph–mass spectrometer (Py-GC/MS). The static tubular furnace as an applied industrial research was used to study deinking sludge pyrolysis. The solid, gas and liquid of products was characterized by electron probe microanalysis (EPMA), gas chromatograph (GC) and gas chromatograph–mass (GC/MS), respectively. The results revealed that the weight-loss process of deinking sludge was a non-isothermal reaction and composed of four stages, i.e. dewater stage, volatile releasing stage, carbon burnout stage and some calcium carbonate decomposition. Pyrolytic products from deinking sludge in the static tubular furnace were comprised of the gaseous (29.78%), condensed liquid (bio-oil, 24.41%) and solid residues (45.81%). The volatiles from deinking sludge pyrolyzing were almost aromatic hydrocarbons, i.e. styrene, toluene and benzene and few acids and the solid was calcium carbonate (CaCO 3 ) that can be reused as paper filler. Deinking sludge was converted into high-grade fuel and chemicals by means of thermochemical conversion techniques, hence, pyrolysis of paper deinking sludge had a promising development on the comprehensive utilization.

Method of Dehydration of Sewage Sludge Using Elements of GEOTUBE Technology at Bortnichy’s Aeration Station

Directory of Open Access Journals (Sweden)

Kashkovsky, V.I.

2014-01-01

Full Text Available The work is dedicated to major environmental and social problem — dehydration of sewage sludge with the help of GeoTube technology elements. The process of dehydration dynamics for different sludge origin has developed. The pilot installation has worked out — filter module placed in the tank of Bortnichy’s sewage treatment plant, where the aerobically-stabilized sludge processed with flocculant Praestol 859 BS and water from filtration fields are delivered to. Installation can be used to reduce the workload on sludge fields, for purification of undersludge returning water and de hydration of accumulated sludge.

Effect of Staged Dissolved Oxygen Optimization on In-situ sludge Reduction and Enhanced Nutrient Removal in an A2MMBR-M System

Science.gov (United States)

Yang, Shan-Shan; Pang, Ji-Wei; Jin, Xiao-Man; Wu, Zhong-Yang; Yang, Xiao-Yin; Guo, Wan-Qian; Zhao, Zhi-Qing; Ren, Nan-Qi

2018-03-01

Redundant excess sludge production and considerable non-standard wastewater discharge from existing activated sludge processes are facing more and more challenges. The investigations on lower sludge production and higher sewage treatment efficiency are urgently needed. In this study, an anaerobic/anoxic/micro-aerobic/oxic-MBR combining a micro-aerobic starvation sludge holding tank (A2MMBR-M) system is developed. Batch tests on the optimization of the staged dissolved oxygen (DO) in the micro-aerobic, the first oxic, and the second oxic tanks were carried out by a 3-factor and 3-level Box-Behnken design (BBD). The optimal actual values of X1 , X2 , and X3 were DO1 of 0.3-0.5 mg/L, DO2 of 3.5-4.5 mg/L, and DO3 of 3-4 mg/L. After the optimization tests, continuous-flow experiments of anaerobic/anoxic/oxic (AAO) and A2MMBR-M systems were further conducted. Compared to AAO system, a 37.45% reduction in discharged excess sludge in A2MMBR-M system was achieved. The COD, TN, and TP removal efficiencies in A2MMBR-M system were respective 4.06%, 2.68%, and 4.04% higher than AAO system. The A2MMBR-M system is proved a promising wastewater treatment technology possessing enhanced in-situ sludge reduction and improved effluent quality. The staged optimized DO concentrations are the key controlling parameters for the realization of simultaneous in-situ sludge reduction and nutrient removal.

The possibility of using a magnetic field for the conditioning of sewage sludge

Directory of Open Access Journals (Sweden)

Kamila Natalia Hrut

2018-04-01

Full Text Available The purpose of the work was to determine the applicability of the magnetic field for the conditioning of the sewage sludge prepared by the dual chemical method with using PIX 113 iron coagulate, and 2 types of organic polyelectrolytes: Superfloc C-494, and Superfloc C-496. In order to assess the impact of process parameters (flow rate and flow direction through the coil, tests were conducted in several research combinations differing in the method of preparation of sludge, the flow direction and flow rate through the solenoid. The analyses were divided into two stages, differing in the applied polyelectrolyte. In order to determine the changes of susceptibility to dewatering, the capillary suction time test, specific resistance to filtration and the final hydrating of the filter cake were used. The assessment of the quality of the leachates was made on the basis of the chemical oxygen demand values. The most beneficial effects of the magnetic field effect were achieved for the combination with the Superfloc C-494 polymer, and flow through the solenoid towards S-N at rate 1.0 L/min. The results shows that the influence of the magnetic field on the susceptibility to dewatering of the sludge is variable, dependent on the flow direction and flow rate of sludge through the coil, as well as on the type of conditioning agent. In order to be able to unequivocally determine the possibility of using a magnetic field for the conditioning of sewage sludge, further research is necessary.

Effect of the two-stage thermal disintegration and anaerobic digestion of sewage sludge on the COD fractions

Directory of Open Access Journals (Sweden)

Ciaciuch Anna

2017-09-01

Full Text Available The research presents the changes in chemical oxygen demand (COD fractions during the two-stage thermal disintegration and anaerobic digestion (AD of sewage sludge in municipal wastewater treatment plant (WWTP. Four COD fractions have been separated taking into account the solubility of substrates and their susceptibility to biodegradation: inert soluble organic matter SI, readily biodegradable substrate SS, slowly biodegradable substrates XS and inert particulate organic material XI. The results showed that readily biodegradable substrates SS (46.8% of total COD and slowly biodegradable substrates XS (36.1% of total COD were dominant in the raw sludge effluents. In sewage effluents after two-stage thermal disintegration, the percentage of SS fraction increased to 90% of total COD and percentage of XS fraction decreased to 8% of total COD. After AD, percentage of SS fraction in total COD decreased to 64%, whereas the percentage of other fractions in effluents increased.

Effect of Fly Ash and Silica Fume on the Mechanical Properties of Cement Paste at Different Stages of Hydration

Science.gov (United States)

2015-08-10

All materials were placed in a clean, labeled stainless steel mixing bowl and weighed to the nearest ten thousandth of a pound. The cement and fly...on the Mechanical Properties of Cement Paste at Different Stages of Hydration This thesis investigates the effect of fly ash and silica fume on... cement paste hydration. Percentages of each additive will replace the cement by volume to be studied at five ages. These percentages will be compared

Sewage sludge conditioning with the application of ash from biomass-fired power plant

Science.gov (United States)

Wójcik, Marta; Stachowicz, Feliks; Masłoń, Adam

2018-02-01

During biomass combustion, there are formed combustion products. Available data indicates that only 29.1 % of biomass ashes were recycled in Poland in 2013. Chemical composition and sorptive properties of ashes enable their application in the sewage sludge treatment. This paper analyses the impact of ashes from biomass-combustion power plant on sewage sludge dewatering and higienisation. The results obtained in laboratory tests proved the possitive impact of biomass ashes on sewage sludge hydration reduction after dewatering and the increase of filtrate volume. After sludge conditioning with the use of biomass combustion by-products, the final moisture content decreased by approximatelly 10÷25 % in comparison with raw sewage sludge depending on the method of dewatering. The application of biomass combustion products in sewage sludge management could provide an alternative method of their utilization according to law and environmental requirements.

Effects Of Various Parameters On The Thickening Of Softening Plant Sludges

DEFF Research Database (Denmark)

Peters, Günther H.J.; Baumann, E. R.; Larson, M. A.

1989-01-01

Spectroscopic and thermal data for sludges from full-scale softening plants showed calcium and magnesium precipitated as calcite and an amorphous hydrated hydroxide, respectively. Magnesium ions were not incorporated into the calcium lattice to form a magnesian calcite. Scanning electron...

Biotransformation of Domestic Wastewater Treatment Plant Sludge by Two-Stage Integrated Processes -Lsb & Ssb

Directory of Open Access Journals (Sweden)

Md. Zahangir Alam, A. H. Molla and A. Fakhru’l-Razi

2012-10-01

Full Text Available The study of biotransformation of domestic wastewater treatment plant (DWTP sludge was conducted in laboratory-scale by two-stage integrated process i.e. liquid state bioconversion (LSB and solid state bioconversion (SSB processes. The liquid wastewater sludge [4% w/w of total suspended solids (TSS] was treated by mixed filamentous fungi Penicillium corylophilum and Aspergillus niger, isolated, screened and mixed cultured in terms of their higher biodegradation potential to wastewater sludge. The biosolids was increased to about 10% w/w. Conversely, the soluble [i.e. Total dissolve solid (TDS] and insoluble substances (TSS in treated supernatant were decreased effectively in the LSB process. In the developed LSB process, 93.8 g kg-1of biosolids were enriched with fungal biomass protein and nutrients (NPK, and 98.8% of TSS, 98.2% of TDS, 97.3% of turbidity, 80.2% of soluble protein, 98.8% of reducing sugar and 92.7% of chemical oxygen demand (COD in treated sludge supernatant were removed after 8 days of treatment. Specific resistance to filtration (1.39x1012 m/kg was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation. The treated biosolids in DWTP sludge was considered as pretreated resource materials for composting and converted into compost by SSB process. The SSB process was evaluated for composting by monitoring the microbial growth and its subsequent roles in biodegradation in composting bin (CB. The process was conducted using two mixed fungal cultures, Trichoderma harzianum with Phanerochaete chrysosporium 2094 and (T/P and T. harzianum and Mucor hiemalis (T/M; and two bulking materials, sawdust (SD and rice straw (RS. The most encouraging results of microbial growth and subsequent solid state bioconversion were exhibited in the RS than the SD. Significant decrease of the C/N ratio and germination index (GI were attained as well as the higher value of glucosamine was exhibited in compost; which

Co-treatment of flotation waste, neutralization sludge, and arsenic-containing gypsum sludge from copper smelting: solidification/stabilization of arsenic and heavy metals with minimal cement clinker.

Science.gov (United States)

Liu, De-Gang; Min, Xiao-Bo; Ke, Yong; Chai, Li-Yuan; Liang, Yan-Jie; Li, Yuan-Cheng; Yao, Li-Wei; Wang, Zhong-Bing

2018-03-01

Flotation waste of copper slag (FWCS), neutralization sludge (NS), and arsenic-containing gypsum sludge (GS), both of which are difficult to dispose of, are major solid wastes produced by the copper smelting. This study focused on the co-treatment of FWCS, NS, and GS for solidification/stabilization of arsenic and heavy metals with minimal cement clinker. Firstly, the preparation parameters of binder composed of FWCS, NS, and cement clinker were optimized to be FWCS dosage of 40%, NS dosage of 10%, cement clinker dosage of 50%, mill time of 1.5 h, and water-to-binder ratio of 0.25. On these conditions, the unconfined compressive strength (UCS) of the binder reached 43.24 MPa after hydration of 28 days. Then, the binder was used to solidify/stabilize the As-containing GS. When the mass ratio of binder-to-GS was 5:5, the UCS of matrix can reach 11.06 MPa after hydration of 28 days, meeting the required UCS level of MU10 brick in China. Moreover, arsenic and other heavy metals in FWCS, NS, and GS were effectively solidified or stabilized. The heavy metal concentrations in leachate were much lower than those in the limits of China standard leaching test (CSLT). Therefore, the matrices were potential to be used as bricks in some constructions. XRD analysis shows that the main hydration products of the matrix were portlandite and calcium silicate hydrate. These hydration products may play a significant role in the stabilization/solidification of arsenic and heavy metals.

Stabilization of chromium-bearing electroplating sludge with MSWI fly ash-based Friedel matrices.

Science.gov (United States)

Qian, Guangren; Yang, Xiaoyan; Dong, Shixiang; Zhou, Jizhi; Sun, Ying; Xu, Yunfeng; Liu, Qiang

2009-06-15

This work investigated the feasibility and effectiveness of MSWI fly ash-based Friedel matrices on stabilizing/solidifying industrial chromium-bearing electroplating sludge using MSWI fly ash as the main raw material with a small addition of active aluminum. The compressive strength, leaching behavior and chemical speciation of heavy metals and hydration phases of matrices were characterized by TCLP, XRD, FTIR and other experimental methods. The results revealed that MSWI fly ash-based Friedel matrices could effectively stabilize chromium-bearing electroplating sludge, the formed ettringite and Friedel phases played a significant role in the fixation of heavy metals in electroplating sludge. The co-disposal of chromium-bearing electroplating sludge and MSWI fly ash-based Friedel matrices with a small addition of active aluminum is promising to be an effective way of stabilizing chromium-bearing electroplating sludge.

Distinguishing between hydrated, partially hydrated or unhydrated clinker in hardened concrete using microscopy

NARCIS (Netherlands)

Valcke, S.L.A.; Rooij, M.R. de; Visser, J.H.M.; Nijland, T.G.

2010-01-01

Hydration of clinker particles is since long a topic of interest in both designing and optimizing cement composition and its quantity used in concrete. The interest for carefully observing and also quantifying the type or stage of clinker hydration in hardened cement paste is twofold. Firstly, the

Characterization of the insoluble sludge from the dissolution of irradiated fast breeder reactor fuel

Energy Technology Data Exchange (ETDEWEB)

Aihara, Haruka; Arai, Yoichi; Shibata, Atsuhiro; Nomura, K.; Takeuchi, M. [Japan Atomic Energy Agency - JAEA, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki, 319-1194 (Japan)

2016-07-01

Insoluble sludge is generated in the reprocessing of spent fuel. The sludge obtained from the dissolution of irradiated fuel from the Joyo experimental fast reactor was analyzed to evaluate its chemical form. The sludge was collected by the filtration of the dissolved fuel solution, and then washed in nitric acid. The yields of the sludge weight were less than 1% of the total fuel weight. The chemical composition of the sludge was analyzed after decomposition by alkaline fusion. Molybdenum, technetium, ruthenium, rhodium, and palladium were found to be the main constituent elements of the sludge. X-ray diffraction patterns of the sludge were attributable to Mo{sub 4}Ru{sub 4}RhPd, regardless of the experimental conditions. The concentrations of molybdenum and zirconium in the dissolved fast reactor fuel solutions were low, indicating that zirconium molybdate hydrate (ZMH) is produced in negligible amounts in the process. (authors)

Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system.

Science.gov (United States)

Tanikawa, D; Syutsubo, K; Hatamoto, M; Fukuda, M; Takahashi, M; Choeisai, P K; Yamaguchi, T

2016-01-01

A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kg COD/(m(3).d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB-DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB-DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process.

Water and sewage sludge disinfection by irradiation. Pt. 3. La desinfection des eaux et des boues residuaires par irradiation. Pt. 3

Energy Technology Data Exchange (ETDEWEB)

Alexandre, D [CEA Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Dept. de Chimie Appliquee

1978-01-01

In view of disinfestation of water and sludges qualitative aspects of irradiation are given. Effects of different parameters: pH, dose rate, hydratation, synergism of oxygen, heat and chlorine are examined. No toxic products are created by radiations. Filtrability and decantability of sludges are improved.

Anaerobic bioleaching of metals from waste activated sludge

KAUST Repository

Meulepas, Roel J W

2015-05-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342μgg-1 of copper, 487μgg-1 of lead, 793μgg-1 of zinc, 27μgg-1 of nickel and 2.3μgg-1 of cadmium. During the anaerobic acidification of 3gdry weightL-1 waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

Enhancement of ultrasonic disintegration of sewage sludge by aeration.

Science.gov (United States)

Zhao, He; Zhang, Panyue; Zhang, Guangming; Cheng, Rong

2016-04-01

Sonication is an effective way for sludge disintegration, which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of sludge. But high energy consumption limits the wide application of sonication. In order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption, aeration was introduced. Results showed that sludge disintegration efficiency was improved significantly by combining aeration with ultrasound. The aeration flow rate, gas bubble size, ultrasonic density and aeration timing had impacts on sludge disintegration efficiency. Aeration that used in later stage of ultrasonic irradiation with low aeration flow rate, small gas bubbles significantly improved ultrasonic disintegration sludge efficiency. At the optimal conditions of 0.4 W/mL ultrasonic irradiation density, 30 mL/min of aeration flow rate, 5 min of aeration in later stage and small gas bubbles, ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was saved. This approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge. Copyright © 2015. Published by Elsevier B.V.

K basins sludge removal sludge pretreatment system

International Nuclear Information System (INIS)

Chang, H.L.

1997-01-01

The Spent Nuclear Fuels Program is in the process of planning activities to remove spent nuclear fuel and other materials from the 100-K Basins as a remediation effort for clean closure. The 105 K- East and K-West Basins store spent fuel, sludge, and debris. Sludge has accumulated in the 1 00 K Basins as a result of fuel oxidation and a slight amount of general debris being deposited, by settling, in the basin water. The ultimate intent in removing the sludge and fuel is to eliminate the environmental risk posed by storing fuel at the K Basins. The task for this project is to disposition specific constituents of sludge (metallic fuel) to produce a product stream through a pretreatment process that will meet the requirements, including a final particle size acceptable to the Tank Waste Remediation System (TWRS). The purpose of this task is to develop a preconceptual design package for the K Basin sludge pretreatment system. The process equipment/system is at a preconceptual stage, as shown in sketch ES-SNF-01 , while a more refined process system and material/energy balances are ongoing (all sketches are shown in Appendix C). Thus, the overall process and 0535 associated equipment have been conservatively selected and sized, respectively, to establish the cost basis and equipment layout as shown in sketches ES- SNF-02 through 08

Hydration status of patients with end-stage renal disease after kidney transplantation.

Science.gov (United States)

Gueutin, Victor; Ficheux, Maxence; Châtelet, Valérie; Lecouf, Angélique; Henri, Patrick; Hurault de Ligny, Bruno; Ryckelynck, Jean-Philippe; Lobbedez, Thierry

2011-01-01

This study was carried out to estimate the modification of hydration status within the first three months of renal transplantation. Fifty patients who underwent a first kidney allograft were prospectively followed for three months after renal transplantation to assess hydration status by bioimpedance spectroscopy. Two hours before the transplant procedure, 10/42 (23.8%) patients were overhydrated. Two days after surgery, 32/40 (80.0%) patients were overhydrated and at three months, 14/27 (51.9%) patients remained fluid-overloaded. Peritoneal dialysis (PD) patients had a lower hydration status (-0.60 L) than hemodialysis (HD) patients (0.70 L; p hydration status before transplantation (p = 0.031). At three months, 12/14 of the overhydrated patients had a creatinine clearance between 30 and 60 mL/min/1.73 m(2) . Patients receiving a first kidney transplant frequently have a hydration disorder. Transplantation is associated with increased hydration status, which seems to persist if DGF or SGF occurs. © 2011 John Wiley & Sons A/S.

Anaerobic bioleaching of metals from waste activated sludge

International Nuclear Information System (INIS)

Meulepas, Roel J.W.; Gonzalez-Gil, Graciela; Teshager, Fitfety Melese; Witharana, Ayoma; Saikaly, Pascal E.; Lens, Piet N.L.

2015-01-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g −1 of copper, 487 μg g −1 of lead, 793 μg g −1 of zinc, 27 μg g −1 of nickel and 2.3 μg g −1 of cadmium. During the anaerobic acidification of 3 g dry weight L −1 waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis

Energy Technology Data Exchange (ETDEWEB)

Li, Meiyan; Xiao, Benyi; Wang, Xu; Liu, Junxin, E-mail: jxliu@rcees.ac.cn

2015-01-15

Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis

International Nuclear Information System (INIS)

Li, Meiyan; Xiao, Benyi; Wang, Xu; Liu, Junxin

2015-01-01

Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others

Recovery of hazardous semiconductor-industry sludge as a useful resource.

Science.gov (United States)

Lee, Tzen-Chin; Liu, Feng-Jiin

2009-06-15

Sludge, a solid waste recovered from wastewater of semiconductor-industries composes of agglomerates of nano-particles like SiO(2) and CaF(2). This sludge deflocculates in acidic and alkaline aqueous solutions into nano-particles smaller than 100 nm. Thus, this sludge is potentially hazardous to water resources when improperly dumped. It can cause considerable air-pollution when fed into rotary-kilns as a raw material for cement production. In this study, dried and pulverized sludge was used to replace 5-20 wt.% Portland cement in cement mortar. The compressive strength of the modified mortar was higher than that of plain cement mortar after curing for 3 days and more. In particular, the strength of mortar with 10 wt.% substitution improved by 25-35% after curing for 7-90 days. TCLP studies reveal no detectable release of heavy metals. Preliminary studies showed that nano-particles deflocculated from the sludge, when cured for up to 3 days retain in the modified mortar their nano-size, which become large-sized hydration compounds that contribute to the final mortar strength. Semiconductor sludge can thus be utilized as a useful resource to replace portion of cement in cement mortar, thereby avoiding their potential hazard on the environment.

Structural and hydration properties of amorphous tricalcium silicate

International Nuclear Information System (INIS)

Mori, K.; Fukunaga, T.; Shiraishi, Y.; Iwase, K.; Xu, Q.; Oishi, K.; Yatsuyanagi, K.; Yonemura, M.; Itoh, K.; Sugiyama, M.; Ishigaki, T.; Kamiyama, T.; Kawai, M.

2006-01-01

Mechanical milling was carried out to synthesize amorphous tricalcium silicate (Ca 3 SiO 5 ) sample, where Ca 3 SiO 5 is the most principal component of Portland cement. The partial phase transformation from the crystalline to the amorphous state was observed by X-ray and neutron diffractions. Moreover, it was found that the structural distortion on the Ca-O correlation exists in the milled Ca 3 SiO 5 . The hydration of the milled Ca 3 SiO 5 with D 2 O proceeds as follows: the formation of hydration products such as Ca(OD) 2 rapidly occurs in the early hydration stage, and then proceeds slowly after about 15 h. The induction time for the hydration of the milled Ca 3 SiO 5 is approximately one half shorter than that for the hydration of the unmilled one. This result means that the mechanical milling brings about the chemical activity of Ca 3 SiO 5 for hydration, and may be particularly useful for increasing the reactivity in the early hydration stage

Microbial Insight into a Pilot-Scale Enhanced Two-Stage High-Solid Anaerobic Digestion System Treating Waste Activated Sludge.

Science.gov (United States)

Wu, Jing; Cao, Zhiping; Hu, Yuying; Wang, Xiaolu; Wang, Guangqi; Zuo, Jiane; Wang, Kaijun; Qian, Yi

2017-11-30

High solid anaerobic digestion (HSAD) is a rapidly developed anaerobic digestion technique for treating municipal sludge, and has been widely used in Europe and Asia. Recently, the enhanced HSAD process with thermal treatment showed its advantages in both methane production and VS reduction. However, the understanding of the microbial community is still poor. This study investigated microbial communities in a pilot enhanced two-stage HSAD system that degraded waste activated sludge at 9% solid content. The system employed process "thermal pre-treatment (TPT) at 70 °C, thermophilic anaerobic digestion (TAD), and mesophilic anaerobic digestion (MAD)". Hydrogenotrophic methanogens Methanothermobacter spp. dominated the system with relative abundance up to about 100% in both TAD and MAD. Syntrophic acetate oxidation (SAO) bacteria were discovered in TAD, and they converted acetate into H₂ and CO₂ to support hydrogenotrophic methanogenesis. The microbial composition and conversion route of this system are derived from the high solid content and protein content in raw sludge, as well as the operational conditions. This study could facilitate the understanding of the enhanced HSAD process, and is of academic and industrial importance.

Anaerobic bioleaching of metals from waste activated sludge

Energy Technology Data Exchange (ETDEWEB)

Meulepas, Roel J.W., E-mail: roel.meulepas@wetsus.nl [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Gonzalez-Gil, Graciela [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Teshager, Fitfety Melese; Witharana, Ayoma [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Saikaly, Pascal E. [King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Lens, Piet N.L. [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands)

2015-05-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g{sup −1} of copper, 487 μg g{sup −1} of lead, 793 μg g{sup −1} of zinc, 27 μg g{sup −1} of nickel and 2.3 μg g{sup −1} of cadmium. During the anaerobic acidification of 3 g{sub dry} {sub weight} L{sup −1} waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner.

Research on the removal of radium from uranium effluent by air-aeration hydrated manganese hydroxide adsorption

International Nuclear Information System (INIS)

Zhang Jianguo; Chen Shaoqing; Qi Jing

2002-01-01

In the acidic leaching uranium process, pyrolusite or manganese oxide (MnO 2 ) powder is often used as an oxidizer. In the processed effluent, manganese ion present as a contaminant in addition to U, Ra, Th, As, Zn, Cu, F, SO 4 2- , etc. Manganese ion content is about 100∼200 mg/1 in effluent. In this case, a new process technique can be developed to treat the effluent using the Mn 2+ present in the effluent. The approach is as follows: The effluent is neutralized by lime milk to pH about 11. As a result, most contaminants are precipitated to meet the uranium effluent discharge standards (U, Th, Mn, SO 4 2- etc.), but radium is still present in the effluent. In this process, manganese ion forms manganese hydroxide Mn(OH) 2 . The manganese hydroxide is easily to oxide to form MnO(OH) 2 by air aeration. This hydrated manganese hydroxide complex can then be used to adsorb radium in effluent. The experiments show: (1) Effluent pH, manganese concentration in effluent, and aeration strength and time etc. influence the radium removal efficiency. Under the test conditions, when manganese in effluent is between 100∼300 mg/l, and pH is over 10.5, radium can be reduced to lower 1.11 Bq/1 in the processed effluent. Higher contents of impurity elements such as aluminum, silicon and magnesium in the effluent affect the removal efficiency; (2) Under the experimental conditions, the lime precipitation air-aeration formed hydrated manganese hydroxide complex sludge is stable. There is no obvious release of radium from the adsorbed hydrated manganese hydroxide complex sludge; (3) The current experiments show that hydrated manganese hydroxide complex sludge has a very good re-adsorption ability for removal of radium from uranium effluent. Some experimental parameters have been measured. (author)

Exergy analysis of a gas-hydrate cool storage system

International Nuclear Information System (INIS)

Bi, Yuehong; Liu, Xiao; Jiang, Minghe

2014-01-01

Based on exergy analysis of charging and discharging processes in a gas-hydrate cool storage system, the formulas for exergy efficiency at the sensible heat transfer stage and the phase change stage corresponding to gas-hydrate charging and discharging processes are obtained. Furthermore, the overall exergy efficiency expressions of charging, discharging processes and the thermodynamic cycle of the gas-hydrate cool storage system are obtained. By using the above expressions, the effects of number of transfer units, the inlet temperatures of the cooling medium and the heating medium on exergy efficiencies of the gas-hydrate cool storage system are emphatically analyzed. The research results can be directly used to evaluate the performance of gas-hydrate cool storage systems and design more efficient energy systems by reducing the sources of inefficiency in gas-hydrate cool storage systems. - Highlights: • Formulas for exergy efficiency at four stages are obtained. • Exergy efficiency expressions of two processes and one cycle are obtained. • Three mainly influencing factors on exergy efficiencies are analyzed. • With increasing the inlet temperature of cooling medium, exergy efficiency increases. • With decreasing the inlet temperature of heating medium, exergy efficiency increases

Irradiated Sewage Sludge for Production of Fennel Plants in Sandy Soil

International Nuclear Information System (INIS)

El-Motaium, R. A.; Abo El-Seoud, M. A.

2004-01-01

Irradiated sewage sludge (SS) has proved to be a useful organic fertilizer particularly for sandy soil. The objective of this study is to compare the response of fennel (Foeniculum vulgare L.) plants growing in sandy soil to different fertilizer regimes, organic vs. mineral. In a field experiment four levels (20, 40, 60, 80 t/ha) of irradiated and non-irradiated sewage sludge were incorporated into sandy soil, in addition to the control treatment (mineral fertilizer). Samples analysis included the biomass production at the vegetative and flowering stages, chlorophyll content, total and reducing sugars and heavy metals content of the shoots. The data indicate that the biomass production has dramatically increased as the sludge application rate increased in both irradiated and non-irradiated plots. However, the increase was significantly higher under all irradiated treatments than the corresponding rates of non-irradiated treatments at both the vegetative and flowering stages. Also, the biomass production at all levels of application was higher than the control, receiving mineral fertilizer. At the vegetative stage, the biomass values ranged from 3.1 g/plant for the control to 10.2 and 34.1 g/plant at 80 t/ha for non-irradiated and irradiated sewage sludge, respectively. Whereas, at the flowering stage the values ranged from 9.8 g/plant for the control to 23.9 and 65.1 g/plant at 80 t/ha for non-irradiated and irradiated sewage sludge, respectively. Total sugars, reducing sugar, non-reducing sugar, and chlorophyll content has increased as the sludge application rate increased. At 80t/ha application rate of irradiated sludge, the reducing sugars content was 29.39 mg/g DW at the vegetative stage and 37.85 mg/g DW at the flowering stage. Reducing sugars recorded lower values in the control plants, 14.54 mg/g DW at the vegetative stage and 18.78 mg/g DW at the flowering stage. Heavy metals (Zn, Fe, Pb, Cd) of the shoots was also determined. Sewage sludge was a good

Evaluation of coagulation sludge from raw water treated with Moringa oleifera for agricultural use

Directory of Open Access Journals (Sweden)

Jhon Jairo Feria

2016-05-01

Full Text Available Coagulation-flocculation is a physical-chemical process responsible for producing the largest amount of sludge in the purification of natural raw water. Conventionally, aluminum sulfate or alum has been used as a coagulant. However, disposal of the sludge produced has been problematic for the environment due to excess aluminum. Currently, the convenience of using natural coagulants such as seed extracts from Moringa oleifera (MO is being studied, although, the properties of sewage sludge produced and its possible reuse are unknown. In this paper the physical-chemical, nutritional and dangerous characteristics from MO sludge were evaluated by using standard methods to verify its potential use in agricultural soils. Results indicated that pH, electrical conductivity, ion exchange capacity, organic matter and micronutrients from sludge were suitable for application to soils with agricultural potential; but deficiency of macronutrients and presence of fecal coliforms limits it to be used as soil improver and not as fertilizer. Sludge stabilization with hydrated lime at doses greater than or equal to 3 % was effective to ensure the elimination of pathogenic microorganisms and to obtain a Class A sludge, unrestricted for agricultural use and suitable for acid soils.

Enhancement of sludge reduction and methane production by removing extracellular polymeric substances from waste activated sludge.

Science.gov (United States)

Nguyen, Minh Tuan; Mohd Yasin, Nazlina Haiza; Miyazaki, Toshiki; Maeda, Toshinari

2014-12-01

The management of waste activated sludge (WAS) recycling is a concern that affects the development of the future low-carbon society, particularly sludge reduction and biomass utilization. In this study, we investigated the effect of removing extracellular polymeric substances (EPS), which play important roles in the adhesion and flocculation of WAS, on increased sludge disintegration, thereby enhancing sludge reduction and methane production by anaerobic digestion. EPS removal from WAS by ethylenediaminetetraacetic acid (EDTA) significantly enhanced sludge reduction, i.e., 49 ± 5% compared with 27 ± 1% of the control at the end the digestion process. Methane production was also improved in WAS without EPS by 8881 ± 109 CH4 μmol g(-1) dry-weight of sludge. Microbial activity was determined by denaturing gradient gel electrophoresis and real-time polymerase chain reaction, which showed that the hydrolysis and acetogenesis stages were enhanced by pretreatment with 2% EDTA, with a larger methanogenic community and better methane production. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of Na2O on the hydration of C3A II. Suspension hydration

NARCIS (Netherlands)

Spierings, G.A.C.M.; Stein, H.N.

1976-01-01

The influence of Na2O on the hydration of C3A was studied in suspensions from the start of the reaction onwards. The heat evolution rate in very early stages of the hydration, measured at varying NaOH concentrations, and SEM, indicate that at NaOH concentrations larger then 0.1 M the reaction

Calcium Aluminate Cement Hydration Model

Directory of Open Access Journals (Sweden)

Matusinović, T.

2011-01-01

Full Text Available Calcium aluminate cement (AC is a very versatile special cement used for specific applications. As the hydration of AC is highly temperature dependent, yielding structurally different hydration products that continuously alter material properties, a good knowledge of thermal properties at early stages of hydration is essential. The kinetics of AC hydration is a complex process and the use of single mechanisms models cannot describe the rate of hydration during the whole stage.This paper examines the influence of temperature (ϑ=5–20 °C and water-to-cement mass ratio (mH /mAC = 0.4; 0.5 and 1.0 on hydration of commercial iron-rich AC ISTRA 40 (producer: Istra Cement, Pula, Croatia, which is a part of CALUCEM group, Figs 1–3. The flow rate of heat generation of cement pastes as a result of the hydration reactions was measured with differential microcalorimeter. Chemically bonded water in the hydrated cement samples was determined by thermo-gravimetry.Far less heat is liberated when cement and water come in contact for the first time, Fig. 1, than in the case for portland cement (PC. Higher water-to-cement ratio increases the heat evolved at later ages (Fig. 3 due to higher quantity of water available for hydration. A significant effect of the water-to-cement ratio on the hydration rate and hydration degree showed the importance of water as being the limiting reactant that slows down the reaction early. A simplified stoichiometric model of early age AC hydration (eq. (8 based on reaction schemes of principal minerals, nominally CA, C12A7 and C4AF (Table 1, was employed. Hydration kinetics after the induction period (ϑ < 20 °C had been successfully described (Fig. 4 and Table 2 by a proposed model (eq. (23 which simultaneously comprised three main mechanisms: nucleation and growth, interaction at phase boundary, and mass transfer. In the proposed kinetic model the nucleation and growth is proportional to the amount of reacted minerals (eq

Composting of sewage sludge with solid fraction of digested pulp from agricultural biogas plant

Science.gov (United States)

Czekała, Wojciech; Dach, Jacek; Przybył, Jacek; Mazurwiekiwcz, Jakub; Janczak, Damian; Lewicki, Andrzej; Smurzyńska, Anna; Kozłowski, Kamil

2018-02-01

Sewage sludge management is an important element of environmental protection. Composting and anaerobic digestion are the biological conversion methods for sewage sludge management. Mass and volume reduction is a result of a properly composted process. Solid fraction of digested pulp can be use as co-substrate, because it is good structural material. The aim of the study was to determine the possibility of composting sewage sludge with a solid fraction of digestate. The compost mix consisted of 25 kilograms of sewage sludge and 20 kilograms solid fraction of digestate in fresh mass. The experiment was carried out in laboratory conditions. Bioreactors of 165 dm3 volume were used. The experiment included two stages. Stage I took place in bioreactors and lasted until the cooling phase of the compost was complete. Stage II included compost maturation for a period of eight months (to 287 day of composting). The reduction of mass obtained at the end of Stage I amounted 30.2%. At the end of Stage II, it was 86.7% relative to the initial weight of the compost. The maximum value of temperature was 75.1°C. Studies have shown that sludge with a solid fraction of digestate can be a suitable substrate for composting with sewage sludge.

Co-hydrothermal treatment of fallen leaves with iron sludge to prepare magnetic iron product and solid fuel.

Science.gov (United States)

Gu, Lin; Li, Binglian; Wen, Haifeng; Zhang, Xin; Wang, Liang; Ye, Jianfeng

2018-06-01

The hydrothermal carbonization (HTC) was performed on Metasequoia Leaves (ML) in the presence of iron sludge, both of which were generated as solid residuals. The relations between sludge, char's properties and operating conditions were systemically investigated. Iron sludge primarily catalyzed the efficient formation of char with higher heating value (HHV) becoming 1.15-1.65 times of ML (18.21 MJ/kg) and was meanwhile reduced to magnetite. The hydrated Fe ions in octahedron crystals acted as nucleophiles facilitating the dehydration and decarboxylation reactions. The increased HHV is found strong temperature dependent while prolonging the residence time is more preferable for low organic acids generation. Thermogravimetric analysis confirmed the iron sludge enhanced conversion of volatile to fixed carbon. The as-prepared solid char showed better stability after catalytic HTC treatment, having ignition temperature increased from 253 to 426 °C as compared to the char prepared without iron sludge addition. Copyright © 2018 Elsevier Ltd. All rights reserved.

Production and remediation of low-sludge, simulated Purex waste glasses, 1: Effects of sludge oxide additions on melter operation

International Nuclear Information System (INIS)

Ramsey, W.G.

1993-01-01

Glass produced during the Purex 4 campaigns of the Integrated Defense Waste Processing Facility (DWPF) Melter System (IDMS) and the 774 Research Melter contained a lower fraction of sludge components than targeted by the Product Composition Control System (PCCS). Purex 4 glass was more durable than the benchmark (EA) glass, but less durable than most simulated SRS high-level waste glasses. Also, Purex 4 glass was considerably less durable than predicted by the algorithm which will be used to control production of DWPF glass. A melter run was performed using the 774 Research Melter to determine if the initial PCCS target composition determined for Purex 4 would produce acceptable glass whose durability could be accurately modeled by Hydration Thermodynamics. Reagent grade oxides and carbonates were added to Purex 4 melter feed stock to simulate a higher sludge loading. Each canister of glass produced was sampled and the composition, crystallinity, and durability was determined. This document details the melter operation and composition and crystallinity analyses

Quality assessment of digested sludges produced by advanced stabilization processes.

Science.gov (United States)

Braguglia, C M; Coors, A; Gallipoli, A; Gianico, A; Guillon, E; Kunkel, U; Mascolo, G; Richter, E; Ternes, T A; Tomei, M C; Mininni, G

2015-05-01

The European Union (EU) Project Routes aimed to discover new routes in sludge stabilization treatments leading to high-quality digested sludge, suitable for land application. In order to investigate the impact of different enhanced sludge stabilization processes such as (a) thermophilic digestion integrated with thermal hydrolysis pretreatment (TT), (b) sonication before mesophilic/thermophilic digestion (UMT), and (c) sequential anaerobic/aerobic digestion (AA) on digested sludge quality, a broad class of conventional and emerging organic micropollutants as well as ecotoxicity was analyzed, extending the assessment beyond the parameters typically considered (i.e., stability index and heavy metals). The stability index was improved by adding aerobic posttreatment or by operating dual-stage process but not by pretreatment integration. Filterability was worsened by thermophilic digestion, either alone (TT) or coupled with mesophilic digestion (UMT). The concentrations of heavy metals, present in ranking order Zn > Cu > Pb > Cr ~ Ni > Cd > Hg, were always below the current legal requirements for use on land and were not removed during the processes. Removals of conventional and emerging organic pollutants were greatly enhanced by performing double-stage digestion (UMT and AA treatment) compared to a single-stage process as TT; the same trend was found as regards toxicity reduction. Overall, all the digested sludges exhibited toxicity to the soil bacterium Arthrobacter globiformis at concentrations about factor 100 higher than the usual application rate of sludge to soil in Europe. For earthworms, a safety margin of factor 30 was generally achieved for all the digested samples.

SBR treatment of tank truck cleaning wastewater: sludge characteristics, chemical and ecotoxicological effluent quality.

Science.gov (United States)

Caluwé, Michel; Dobbeleers, Thomas; Daens, Dominique; Geuens, Luc; Blust, Ronny; Dries, Jan

2017-08-02

A lab-scale activated sludge sequencing batch reactor (SBR) was used to treat tank truck cleaning (TTC) wastewater with different operational strategies (identified as different stages). The first stage was an adaptation period for the seed sludge that originated from a continuous fed industrial plant treating TTC wastewater. The first stage was followed by a dynamic reactor operation based on the oxygen uptake rate (OUR). Thirdly, dynamic SBR control based on OUR treated a daily changing influent. Lastly, the reactor was operated with a gradually shortened fixed cycle. During operation, sludge settling evolved from nearly no settling to good settling sludge in 16 days. The sludge volume index improved from 200 to 70 mL gMLSS -1 in 16 days and remained stable during the whole reactor operation. The average soluble chemical oxygen demand (sCOD) removal varied from 87.0% to 91.3% in the different stages while significant differences in the food to mass ratio were observed, varying from 0.11 (stage I) to 0.37 kgCOD.(kgMLVSS day) -1 (stage III). Effluent toxicity measurements were performed with Aliivibrio fischeri, Daphnia magna and Pseudokirchneriella subcapitata. Low sensitivity of Aliivibrio was observed. A few samples were acutely toxic for Daphnia; 50% of the tested effluent samples showed an inhibition of 100% for Pseudokirchneriella.

Radiotracer study on the efficiency of a cylindrical 2-stage anaerobic sludge digester

International Nuclear Information System (INIS)

Sung-Hee Jung; Joon-Ha Jin; Jong-Bum Kim

2004-01-01

Radiotracer experiments were carried out on a cylindrical 2-stage anaerobic sludge digester in order to investigate the improvement of their efficiency by means of RTD (residence time distribution) measurements before and after cleaning up the inside of the digester. The tracer was scandium in an EDTA solution which forms such a stable complex compound to keep the isotope form being adsorbed onto the surface of the pipelines or the wall. It was injected into the digester by pressurized nitrogen gas and its movement was monitored by NaI(Tl) scintillation detectors installed around the digester and recorded for a month by a 24-channel data acquisition system specially developed for radiotracer experiments by the Korea Tracer Group of KAERI. The experimental data was analysed for the MRT (mean residence time) and other parameters characterizing the flow behaviour. (author)

Recycling of spent catalyst and waste sludge from industry to substitute raw materials in the preparation of Portland cement clinker

Directory of Open Access Journals (Sweden)

Kae-Long Lin

2017-09-01

Full Text Available This study investigated the feasibility of using waste limestone sludge, waste stone sludge, iron oxide sludge, and spent catalyst as raw materials in the production of eco-cement. The compressive strength development of the Eco Cement-A (ECO-A paste was similar to that of ordinary Portland cement (OPC pastes. The compressive strength development of the ECO-B paste was higher than that of OPC pastes. In addition, the C2S (Ca2SiO4, C2S and C3S (Ca3SiO5 minerals in the eco-cement paste were continuously utilized to hydrate the Ca(OH2 and calcium silicate hydrates gel (Ca6Si3O12·H2O, C–S–H throughout the curing time. When ECO-C clinker contained 8% spent catalyst, the C3S mineral content decreased and C3A (3 CaO·Al2O3 content increased, thereby causing the structure to weaken and compressive strength to decrease. The results showed that the developed eco-cement with 4% spent catalyst possessed compressive strength properties similar to those of OPC pastes.

Technical and economical feasibility study of a sewage sludge disinfection plants by irradiation process

International Nuclear Information System (INIS)

Rojas Bustos, Gustavo

1999-01-01

This report presents a technical and economical evaluation for a disinfection plant of sewage sludge based on irradiation. The process starts after sludge stabilization which is achieved by anaerobic digestion. It includes two stages, plus an optional: the first corresponds to dewatering of sewage sludge up to a solids content between 20 and 25 %, the second stage corresponds to disinfection by gamma or electron beam irradiation, and the third, which is optional, corresponds to the drying of sewage sludge up to a water content of 50%, which allows to diminish significantly the volumes of solids to be transported. If this stage is not accomplished the final product corresponds to a sewage sludge with 25 % of dry solids, which can also be disposed in agricultural land. Process was designed to treat 60 tons per day of sewage sludge (dry matter basis). The report presents the design of process equipment, principal and auxiliary, the investment and operational cost estimations as well as the total cost of treatment per ton of sewage sludge. A sensitivity analysis is also included to determine the influence of operational process parameters in operational and investment costs. The results showed that a sewage sludge plant including dewatering and disinfection process through gamma irradiation, achieves a capital investment of about US$ 12.000.000 with a treatment cost per ton of dry sludge of US$140. Including the optional air-drying stage, the total cost of treatment is about US$148 per ton of dry matter. In the case of electron beam irradiation the capital investment achieves a value of US$ 11 millions with a total treatment cost of US$ 136 per ton of dry matter. These values resulted quite similar to the cost of alternative treatment, i.e., disposal in a dedicated landfill. (L.V.)

Economic assessment of biodiesel production from wastewater sludge.

Science.gov (United States)

Chen, Jiaxin; Tyagi, Rajeshwar Dayal; Li, Ji; Zhang, Xiaolei; Drogui, Patrick; Sun, Feiyun

2018-04-01

Currently, there are mainly two pathways of the biodiesel production from wastewater sludge including 1) directly extracting the lipid in sludge and then converting the lipid to biodiesel through trans-esterification, and 2) employing sludge as medium to cultivate oleaginous microorganism to accumulate lipid and then transferring the lipid to biodiesel. So far, the study was still in research stage and its cost feasibility was not yet investigated. In this study, biodiesel production from wastewater sludge was designed and the cost was estimated with SuperPro Designer. With consideration of converting the lipid in raw sludge to biodiesel, the unit production cost was 0.67 US $/kg biodiesel (0.59 US $/L biodiesel). When the sludge was used as medium to grow oleaginous microorganism to accumulate lipid for producing biodiesel, the unit production cost was 1.08 US $/kg biodiesel (0.94 US $/L biodiesel). The study showed that sludge has great potential in biodiesel production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor.

Science.gov (United States)

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-10-15

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

Science.gov (United States)

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-01-01

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria. PMID:26555802

Process for treating waters and sludges and device for developing this process

International Nuclear Information System (INIS)

Levaillant, Claude.

1977-01-01

The description is given of a process for treating waters and sludge by means of a ionizing radiation beam, featuring the following stages: settlement of primary waters and sludge, centrifugation of the settled waters and sludge in order to separate the waste waters, the sludge formed of organic compounds charged with heavy metals and the sludge formed of mineral compounds, irradiation, by ionizing radiation beam, of the sludge formed of organic compounds, containing heavy metals, and which are transformed into less toxic and denser recoverable mineral compounds, centrifugation of the irradiated sludge making it possible to obtain clarified waters treated by irradiation, sludge composed of organic compounds freed of their heavy metals and sludge formed of mineral compounds containing heavy metals and which will be easily separated owing to their high density [fr

Combustion of Sewage Sludge as Alternative Fuel for Cement Industry

Institute of Scientific and Technical Information of China (English)

LI Fuzhou; ZHANG Wei

2011-01-01

The combustion of sewage sludge and coal was studied by thermogravimetric analysis.Both differential scanning calorimetric analysis and derivative thermogravimetric profiles showed differences between combustion of sewage sludge and coal, and non-isothermal kinetics analysis method was applied to evaluate the combustion process. Based on Coats-Redfem integral method, some reaction models were tested,the mechanism and kinetics of the combustion reaction were discussed. The results show that the combustion of sewage sludge is mainly in the Iow temperature stage, meanwhile the ignition temperature and Arrhenius activation energy are lower than that of coal. The combustion of sewage sludge has the advantage over coal in some aspects, thus sewage sludge can partly replace coal used as cement industry fuel.

Profiles and drivers of antibiotic resistance genes distribution in one-stage and two-stage sludge anaerobic digestion based on microwave-H2O2 pretreatment.

Science.gov (United States)

Zhang, Junya; Liu, Jibao; Wang, Yawei; Yu, Dawei; Sui, Qianwen; Wang, Rui; Chen, Meixue; Tong, Juan; Wei, Yuansong

2017-10-01

Three anaerobic digestion (AD) processes of waste activated sludge (WAS) were established including the control (mono-WAS), one-stage AD and two-stage AD along with microwave-H 2 O 2 pre-treatment (MW-H 2 O 2 ) to investigate the profiles and drivers of antibiotic resistance genes (ARGs) distribution concerning co-selection from heavy metals, intI1 and microbial community through qPCR and high-throughput sequencing method. Results showed that MW-H 2 O 2 could reduce the absolute gene copies of all ARGs while increased the relative abundance of most ARGs. After subsequent AD, both total ARGs quantities and relative abundance were enriched while two-stage AD showed some advantages over ARGs abundance reduction. Besides, AD was more effective on the potential pathogens reduction than MW-H 2 O 2 . AD could reduce the role of intI1 on the spread of ARGs, while mantel test and procrustes analysis indicated that the variation of ARGs abundance was closely associated with the discrepancy of bacterial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of hydraulic retention time and sludge recirculation on greenhouse gas emission and related microbial communities in two-stage membrane bioreactor treating solid waste leachate.

Science.gov (United States)

Nuansawan, Nararatchporn; Boonnorat, Jarungwit; Chiemchaisri, Wilai; Chiemchaisri, Chart

2016-06-01

Methane (CH4) and nitrous oxide (N2O) emissions and responsible microorganisms during the treatment of municipal solid waste leachate in two-stage membrane bioreactor (MBR) was investigated. The MBR system, consisting of anaerobic and aerobic stages, were operated at hydraulic retention time (HRT) of 5 and 2.5days in each reactor under the presence and absence of sludge recirculation. Organic and nitrogen removals were more than 80% under all operating conditions during which CH4 emission were found highest under no sludge recirculation condition at HRT of 5days. An increase in hydraulic loading resulted in a reduction in CH4 emission from anaerobic reactor but an increase from the aerobic reactor. N2O emission rates were found relatively constant from anaerobic and aerobic reactors under different operating conditions. Diversity of CH4 and N2O producing microorganisms were found decreasing when hydraulic loading rate to the reactors was increased. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sludge disinfection using gamma radiation: a sound option for Albuquerque

International Nuclear Information System (INIS)

Noland, P.D.; Khera, A.K.

1980-01-01

The City of Albuquerque has disposed of its anaerobically digested dried sludge cake on City and county parks for many years. If the City is to continue such beneficial use of sludge, it must now provide a supplementary disinfection process in order to meet the recent EPA regulations governing land application of sewage sludges. In light of these recent regulations and soaring costs of electrical energy, the City of Albuquerque recently completed a comprehensive sludge management study. This study is intended to supplement the areawide facilities plan completed in 1976. Among the various alternatives evaluated, the most feasible was the continued use of dried sludge cake on City parks and sale of excess sludge cake as an unlimited use soil conditioner and fertilizer. This sludge would be disinfected by gamma irradiation. The proposed solids management system would consist of two-stage anaerobic digestion and pipeline transfer to dewatering, disinfection, and stockpiling facilities at a remote tract approximately 5 miles from the treatment plant

Photovoltaic's silica-rich waste sludge as supplementary cementitious material (SCM)

International Nuclear Information System (INIS)

Quercia, G.; Putten, J.J.G. van der; Hüsken, G.; Brouwers, H.J.H.

2013-01-01

Waste sludge, a solid recovered from wastewater of photovoltaic-industries, composes of agglomerates of nano-particles like SiO 2 and CaCO 3 . This sludge deflocculates in aqueous solutions into nano-particles smaller than 1 μm. Thus, this sludge constitutes a potentially hazardous waste when it is improperly disposed. Due to its high content of amorphous SiO 2 , this sludge has a potential use as supplementary cementitious material (SCM) in concrete. In this study the main properties of three different samples of photovoltaic's silica-rich waste sludge (nSS) were physically and chemically characterized. The characterization techniques included: scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen physical adsorption isotherm (BET method), density by Helium pycnometry, particle size distribution determined by laser light scattering (LLS) and zeta-potential measurements by dynamic light scattering (DLS). In addition, a dispersability study was performed to design stable slurries to be used as liquid additives for the concrete production on site. The effects on the hydration kinetics of cement pastes by the incorporation of nSS in the designed slurries were determined using an isothermal calorimeter. A compressive strength test of standard mortars with 7% of cement replacement was performed to determine the pozzolanic activity of the waste nano-silica sludge. Finally, the hardened system was fully characterized to determine the phase composition. The results demonstrate that the nSS can be utilized as SCM to replace portion of cement in mortars, thereby decreasing the CO 2 footprint and the environmental impact of concrete. -- Highlights: •Three different samples of PV nano-silica sludge (nSS) were fully characterized. •nSS is composed of agglomerates of nano-particles like SiO 2 and CaCO 3 . •Dispersability studies demonstrated that nSS agglomerates are broken to nano-size. •nSS can be classified

[Effects of ultrasonic pretreatment on drying characteristics of sewage sludge].

Science.gov (United States)

Li, Run-Dong; Yang, Yu-Ting; Li, Yan-Long; Niu, Hui-Chang; Wei, Li-Hong; Sun, Yang; Ke, Xin

2009-11-01

The high water content of sewage sludge has engendered many inconveniences to its treatment and disposal. While ultrasonic takes on unique advantages on the sludge drying because of its high ultrasonic power, mighty penetrating capability and the ability of causing cavitations. Thus this research studies the characteristics influences of ultrasonic bring to the sludge drying and effects of the exposure time, ultrasonic generator power, temperatures of ultrasonic and drying temperature on the drying characteristics of dewatered sludge. Results indicate that ultrasonic pretreatment could speed up evaporation of the free water in sludge surface and help to end the drying stage with constant speed. In addition, ultrasonic treatment can effectively improve the sludge drying efficiency which could be more evident with the rise of the ultrasonic power (100-250 W), ultrasonic temperature and drying temperature. If dried under low temperature such as 105 degrees C, sludge will have premium drying characteristics when radiated under ultrasound for a shorter time such as 3 min. In the end, the ultrasonic treatment is expected to be an effective way to the low-cost sludge drying and also be an important reference to the optimization of the sludge drying process because of its effects on the increase of sludge drying efficiency.

Environmentally safe management of radioactive and toxic sludges

International Nuclear Information System (INIS)

Shingarev, N.E.; Mukhin, I.V.; Polyakov, A.S.; Raginsky, L.S.; Semenov, B.A.

2000-01-01

Toxic industrial wastes constitute a significant part of Russian natural environment. The most reliable route to provide the long-term ecologic safety involves removal of toxicants or radioactive substances from polluted sites. With a view of processing toxic and radioactive sludges available in reservoirs, a process flowsheet is suggested that comprises the operations of sludge concentration, dehydration and granulation.Flocculation is an operation required to concentrate a solid phase. Polyacrylamide (PAA) and hydrolyzed PAA (HPAA) are standard flocculating agents used in the processing of sludges coming from storage facilities of radioactive wastes. HPAA is less efficient and it is shown that the optimized concentration of PAA is 4 mg/g solid. Flotation agents are used to extract the solid phase of sludges, it is shown that the process of extraction has to be carried out in 2 stages, the first flotation cycle with a Ph value between 7.5 and 9.5 and the second with a Ph adjustment to 3.5-6.0.The cake resulting from the sludge filtration has poor technological properties, it is advisable to produce a granular material. Hydro-granulation using hydrophobic flocculating agents may be implemented immediately after sludge concentration. The other granulation technique involves the sol-gel process used to incorporate sludge into a ceramic (aluminium oxide) matrix

Review on innovative techniques in oil sludge bioremediation

Science.gov (United States)

Mahdi, Abdullah M. El; Aziz, Hamidi Abdul; Eqab, Eqab Sanoosi

2017-10-01

Petroleum hydrocarbon waste is produced in worldwide refineries in significant amount. In Libya, approximately 10,000 tons of oil sludge is generated in oil refineries (hydrocarbon waste mixtures) annually. Insufficient treatment of those wastes can threaten the human health and safety as well as our environment. One of the major challenges faced by petroleum refineries is the safe disposal of oil sludge generated during the cleaning and refining process stages of crude storage facilities. This paper reviews the hydrocarbon sludge characteristics and conventional methods for remediation of oil hydrocarbon from sludge. This study intensively focuses on earlier literature to describe the recently selected innovation technology in oily hydrocarbon sludge bioremediation process. Conventional characterization parameters or measurable factors can be gathered in chemical, physical, and biological parameters: (1) Chemical parameters are consequently necessary in the case of utilization of topsoil environment when they become relevant to the presence of nutrients and toxic compounds; (2) Physical parameters provide general data on sludge process and hand ability; (3) Biological parameters provide data on microbial activity and organic matter presence, which will be used to evaluate the safety of the facilities. The objective of this research is to promote the bioremediating oil sludge feasibility from Marsa El Hariga Terminal and Refinery (Tobruk).

Nonequilibrium Thermodynamics of Hydrate Growth on a Gas-Liquid Interface

Science.gov (United States)

Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

2018-04-01

We develop a continuum-scale phase-field model to study gas-liquid-hydrate systems far from thermodynamic equilibrium. We design a Gibbs free energy functional for methane-water mixtures that recovers the isobaric temperature-composition phase diagram under thermodynamic equilibrium conditions. The proposed free energy is incorporated into a phase-field model to study the dynamics of hydrate formation on a gas-liquid interface. We elucidate the role of initial aqueous concentration in determining the direction of hydrate growth at the interface, in agreement with experimental observations. Our model also reveals two stages of hydrate growth at an interface—controlled by a crossover in how methane is supplied from the gas and liquid phases—which could explain the persistence of gas conduits in hydrate-bearing sediments and other nonequilibrium phenomena commonly observed in natural methane hydrate systems.

Supramolecular Organization of Nonstoichiometric Drug Hydrates: Dapsone

Science.gov (United States)

Braun, Doris E.; Griesser, Ulrich J.

2018-01-01

The observed moisture- and temperature dependent transformations of the dapsone (4,4′-diaminodiphenyl sulfone, DDS) 0. 33-hydrate were correlated to its structure and the number and strength of the water-DDS intermolecular interactions. A combination of characterization techniques was used, including thermal analysis (hot-stage microscopy, differential scanning calorimetry and thermogravimetric analysis), gravimetric moisture sorption/desorption studies and variable humidity powder X-ray diffraction, along with computational modeling (crystal structure prediction and pair-wise intermolecular energy calculations). Depending on the relative humidity the hydrate contains between 0 and 0.33 molecules of water per molecule DDS. The crystal structure is retained upon dehydration indicating that DDS hydrate shows a non-stoichiometric (de)hydration behavior. Unexpectedly, the water molecules are not located in structural channels but at isolated-sites of the host framework, which is counterintuitively for a hydrate with non-stoichiometric behavior. The water-DDS interactions were estimated to be weaker than water-host interactions that are commonly observed in stoichiometric hydrates and the lattice energies of the isomorphic dehydration product (hydrate structure without water molecules) and (form III) differ only by ~1 kJ mol−1. The computational generation of hypothetical monohydrates confirms that the hydrate with the unusual DDS:water ratio of 3:1 is more stable than a feasible monohydrate structure. Overall, this study highlights that a deeper understanding of the formation of hydrates with non-stoichiometric behavior requires a multidisciplinary approach including suitable experimental and computational methods providing a firm basis for the development and manufacturing of high quality drug products. PMID:29520359

Visual observation of gas hydrates nucleation and growth at a water - organic liquid interface

Science.gov (United States)

Stoporev, Andrey S.; Semenov, Anton P.; Medvedev, Vladimir I.; Sizikov, Artem A.; Gushchin, Pavel A.; Vinokurov, Vladimir A.; Manakov, Andrey Yu.

2018-03-01

Visual observation of nucleation sites of methane and methane-ethane-propane hydrates and their further growth in water - organic liquid - gas systems with/without surfactants was carried out. Sapphire Rocking Cell RCS6 with transparent sapphire cells was used. The experiments were conducted at the supercooling ΔTsub = 20.2 °C. Decane, toluene and crude oils were used as organics. Gas hydrate nucleation occurred on water - metal - gas and water - sapphire - organic liquid three-phase contact lines. At the initial stage of growth hydrate crystals rapidly covered the water - gas or water - organics interfaces (depending on the nucleation site). Further hydrate phase accrete on cell walls (sapphire surface) and into the organics volume. At this stage, growth was accompanied by water «drawing out» from under initial hydrate film formed at water - organic interface. Apparently, it takes place due to water capillary inflow in the reaction zone. It was shown that the hydrate crystal morphology depends on the organic phase composition. In the case of water-in-decane emulsion relay hydrate crystallization was observed in the whole sample, originating most likely due to the hydrate crystal intergrowth through decane. Contacts of such crystals with adjacent water droplets result in rapid hydrate crystallization on this droplet.

Lifecycle analysis of renewable natural gas and hydrocarbon fuels from wastewater treatment plants’ sludge

Energy Technology Data Exchange (ETDEWEB)

Lee, Uisung [Argonne National Lab. (ANL), Argonne, IL (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Urgun Demirtas, Meltem [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Tao, Ling [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-09-01

Wastewater treatment plants (WWTPs) produce sludge as a byproduct when they treat wastewater. In the United States, over 8 million dry tons of sludge are produced annually just from publicly owned WWTPs. Sludge is commonly treated in anaerobic digesters, which generate biogas; the biogas is then largely flared to reduce emissions of methane, a potent greenhouse gas. Because sludge is quite homogeneous and has a high energy content, it is a good potential feedstock for other conversion processes that make biofuels, bioproducts, and power. For example, biogas from anaerobic digesters can be used to generate renewable natural gas (RNG), which can be further processed to produce compressed natural gas (CNG) and liquefied natural gas (LNG). Sludge can be directly converted into hydrocarbon liquid fuels via thermochemical processes such as hydrothermal liquefaction (HTL). Currently, the environmental impacts of converting sludge into energy are largely unknown, and only a few studies have focused on the environmental impacts of RNG produced from existing anaerobic digesters. As biofuels from sludge generate high interest, however, existing anaerobic digesters could be upgraded to technology with more economic potential and more environmental benefits. The environmental impacts of using a different anaerobic digestion (AD) technology to convert sludge into energy have yet to be analyzed. In addition, no studies are available about the direct conversion of sludge into liquid fuels. In order to estimate the energy consumption and greenhouse gas (GHG) emissions impacts of these alternative pathways (sludge-to-RNG and sludge-to-liquid), this study performed a lifecycle analysis (LCA) using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model. The energy uses and GHG emissions associated with the RNG and hydrocarbon liquid are analyzed relative to the current typical sludge management case, which consists of a single-stage mesophilic

The destruction of parasitic resistant stages in sewage sludge by irradiation with low accelerating voltage electrons

International Nuclear Information System (INIS)

Enigk, K.; Holl, P.; Dey-Hazra, A.; Polymer-Physik G.m.b.H. und Co. K.G., Tuebingen

1975-01-01

The destroying effect of ionizing radiation on parasitic resistant stages in sludge has been tested. Suitable for that process is an electron beam accelerator which will be provided with energy from the electric power supply network which can be switched on and off according to the requirements. Such modern utilities have an enormous beam capacity and a high operating safety. The process is working according to the continuous flow principle and at room temperature. In a series of 13 experiments the effect of different doses has been tested. A dose of 480 kRad (accelerating voltage: 400 kV, beam current: 10 mA , irradiation time: 24 sec.) can easily obtained in practical work and is economically acceptable. By these means approximately 97% of the following parasitic stages have been destroyed: undeveloped eggs of Ascaris suum, Trichuris suis, Fasciola hepatica and gastrointestinal strongylids of pigs, embryonated eggs of Capillaria obsignata and probably of Taenia spec. A few third-stage larvae of Oesophagostomum (Strongylidae) of pigs survived even 108 sec of irradiation; however, they did not develop to maturity in the definitive host. Approximately 25% of the sporulated oocysts of Eimeria tenella were still infective after 108 sec of irradiation. (orig.) [de

Thermal analysis and FTIR studies of sewage sludge produced in treatment plants. The case of sludge in the city of Uberlandia-MG, Brazil

Energy Technology Data Exchange (ETDEWEB)

Oliveira Silva, Jader de [Instituto de Quimica da Universidade Federal de Uberlandia, Av. Joao Naves de Avila, 2121, CEP 38400-902, Cx. Postal 593, Uberlandia - Minas Gerais (Brazil); Departamento Municipal de Agua e Esgoto de Uberlandia (DMAE) (Brazil); Filho, Guimes Rodrigues, E-mail: guimes@ufu.br [Instituto de Quimica da Universidade Federal de Uberlandia, Av. Joao Naves de Avila, 2121, CEP 38400-902, Cx. Postal 593, Uberlandia - Minas Gerais (Brazil); Silva Meireles, Carla da; Dias Ribeiro, Sabrina; Vieira, Julia Graciele [Instituto de Quimica da Universidade Federal de Uberlandia, Av. Joao Naves de Avila, 2121, CEP 38400-902, Cx. Postal 593, Uberlandia - Minas Gerais (Brazil); Vieira da Silva, Cleuzilene [Faculdade de Engenharia Quimica da Universidade Federal de Uberlandia (Brazil); Alves Cerqueira, Daniel [Instituto de Ciencias Ambientais e Desenvolvimento Sustentavel da Universidade Federal da Bahia (Brazil)

2012-01-20

Highlights: Black-Right-Pointing-Pointer In this study, the sludge was characterized by thermal analyses and FTIR. Black-Right-Pointing-Pointer The superior calorific value of the sludge was 16.2 MJ kg{sup -1}. Black-Right-Pointing-Pointer The sludge showed a significant biodegradable portion of 65%. Black-Right-Pointing-Pointer The UASB sludge can be used for energy source. - Abstract: The operation of anaerobic reactors in Brazil creates a by-product, sewage sludge, for which adequate treatment is necessary to obtain a solid and stable material. The burning of sewage sludge may be an effective alternative for its management, and looking to enhance its energy potential, an environmentally friendly method of disposal is necessary. As the quantity of sludge generated has increased over the past few years, the physical chemical characterization of this waste is the first stage for its utilization as raw material. The material was characterized by thermal analyses (Thermogravimetry (TG)/Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC)) and Infrared Analysis (FTIR) in order to determine the main organic groups present in sludge. The calorific power of the anaerobically digested sludge of Uberlandia-MG, Brazil was measured, and an energy content equal to 16.2 MJ kg{sup -1} was found, which is within the range of values reported in the literature.

METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

Energy Technology Data Exchange (ETDEWEB)

Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

2005-02-01

Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the

Biodegradation studies of oil sludge containing high hydrocarbons concentration

International Nuclear Information System (INIS)

Olguin-Lora, P.; Munoz-Colunga, A.; Castorena-Cortes, G.; Roldan-Carrillo, T.; Quej Ake, L.; Reyes-Avila, J.; Zapata-Penasco, I.; Marin-Cruz, J.

2009-01-01

Oil industry has a significant impact on environment due to the emission of, dust, gases, waste water and solids generated during oil production all the way to basic petrochemical product manufacturing stages. the aim of this work was to evaluate the biodegradation of sludge containing high hydrocarbon concentration originated by a petroleum facility. A sludge sampling was done at the oil residuals pool (ORP) on a gas processing center. (Author)

Numerical Simulations for Enhanced Methane Recovery from Gas Hydrate Accumulations by Utilizing CO2 Sequestration

Science.gov (United States)

Sridhara, Prathyusha

transport properties with change in pressure and temperature due to the presence of the simple CO2-hydrate and mixed hydrates (mainly CH4-CO2 hydrate and CH4 -CO2-N2 hydrate) in the porous geologic media. These simulations on CO2/ CH4-CO2 hydrate reservoirs provided a basic insight to formulate and interpret a novel technological approach. This approach aims at prediction of enhanced gas production profiles from Class 2 hydrate accumulations by utilizing CO2 sequestration. The approach also offers a possibility to permanently store CO 2 in the geologic formation to a greater extent compared to a direct injection of CO2 into gas hydrate sediments. The production technique implies a three-stage approach using one vertical well design. In Stage I, the CO2 is injected into the underlying aquifer. In Stage II, the well is shut in and injected CO2 is allowed to be converted into immobile CO2 hydrate. Finally, during Stage III, decomposition of CH4 hydrate is induced by the depressurization method. The gas production potential is estimated over 15 years. The results reveal that methane production is increased together with simultaneous reduction of concomitant water production rate comparing to a conventional Class 2 reservoir production.

Thermal analysis and FTIR studies of sewage sludge produced in treatment plants. The case of sludge in the city of Uberlândia-MG, Brazil

International Nuclear Information System (INIS)

Oliveira Silva, Jader de; Filho, Guimes Rodrigues; Silva Meireles, Carla da; Dias Ribeiro, Sabrina; Vieira, Júlia Graciele; Vieira da Silva, Cleuzilene; Alves Cerqueira, Daniel

2012-01-01

Highlights: ► In this study, the sludge was characterized by thermal analyses and FTIR. ► The superior calorific value of the sludge was 16.2 MJ kg −1 . ► The sludge showed a significant biodegradable portion of 65%. ► The UASB sludge can be used for energy source. - Abstract: The operation of anaerobic reactors in Brazil creates a by-product, sewage sludge, for which adequate treatment is necessary to obtain a solid and stable material. The burning of sewage sludge may be an effective alternative for its management, and looking to enhance its energy potential, an environmentally friendly method of disposal is necessary. As the quantity of sludge generated has increased over the past few years, the physical chemical characterization of this waste is the first stage for its utilization as raw material. The material was characterized by thermal analyses (Thermogravimetry (TG)/Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC)) and Infrared Analysis (FTIR) in order to determine the main organic groups present in sludge. The calorific power of the anaerobically digested sludge of Uberlândia-MG, Brazil was measured, and an energy content equal to 16.2 MJ kg −1 was found, which is within the range of values reported in the literature.

LABORATORY STRATEGIES FOR HYDRATE FORMATION IN FINE-GRAINED SEDIMENTS

KAUST Repository

Lei, L.; Santamarina, Carlos

2018-01-01

Fine‐grained sediments limit hydrate nucleation, shift the phase boundary and hinder gas supply. Laboratory experiments in this study explore different strategies to overcome these challenges, including the use of a more soluble guest molecule rather than methane, grain‐scale gas‐storage within porous diatoms, ice‐to‐hydrate transformation to grow lenses at predefined locations, forced gas injection into water saturated sediments, and long‐term guest molecule transport. Tomographic images, thermal and pressure data provide rich information on hydrate formation and morphology. Results show that hydrate formation is inherently displacive in fine‐grained sediments; lenses are thicker and closer to each other in compressible, high specific surface area sediments subjected to low effective stress. Temperature and pressure trajectories follow a shifted phase boundary that is consistent with capillary effects. Exo‐pore growth results in freshly formed hydrate with a striped and porous structure; this open structure becomes an effective pathway for gas transport to the growing hydrate front. Ice‐to‐hydrate transformation goes through a liquid stage at pre‐melt temperatures; then, capillarity and cryogenic suction compete, and some water becomes imbibed into the sediment faster than hydrate reformation. The geometry of hydrate lenses and the internal hydrate structure continue evolving long after the exothermal response to hydrate formation has completely decayed. Multiple time‐dependent processes occur during hydrate formation, including gas, water and heat transport, sediment compressibility, reaction rate and the stochastic nucleation process. Hydrate formation strategies conceived for this study highlight the inherent difficulties in emulating hydrate formation in fine‐grained sediments within the relatively short time‐scale available for laboratory experiments.

LABORATORY STRATEGIES FOR HYDRATE FORMATION IN FINE-GRAINED SEDIMENTS

KAUST Repository

Lei, L.

2018-04-02

Fine‐grained sediments limit hydrate nucleation, shift the phase boundary and hinder gas supply. Laboratory experiments in this study explore different strategies to overcome these challenges, including the use of a more soluble guest molecule rather than methane, grain‐scale gas‐storage within porous diatoms, ice‐to‐hydrate transformation to grow lenses at predefined locations, forced gas injection into water saturated sediments, and long‐term guest molecule transport. Tomographic images, thermal and pressure data provide rich information on hydrate formation and morphology. Results show that hydrate formation is inherently displacive in fine‐grained sediments; lenses are thicker and closer to each other in compressible, high specific surface area sediments subjected to low effective stress. Temperature and pressure trajectories follow a shifted phase boundary that is consistent with capillary effects. Exo‐pore growth results in freshly formed hydrate with a striped and porous structure; this open structure becomes an effective pathway for gas transport to the growing hydrate front. Ice‐to‐hydrate transformation goes through a liquid stage at pre‐melt temperatures; then, capillarity and cryogenic suction compete, and some water becomes imbibed into the sediment faster than hydrate reformation. The geometry of hydrate lenses and the internal hydrate structure continue evolving long after the exothermal response to hydrate formation has completely decayed. Multiple time‐dependent processes occur during hydrate formation, including gas, water and heat transport, sediment compressibility, reaction rate and the stochastic nucleation process. Hydrate formation strategies conceived for this study highlight the inherent difficulties in emulating hydrate formation in fine‐grained sediments within the relatively short time‐scale available for laboratory experiments.

Parasites in soil/sludge systems

Energy Technology Data Exchange (ETDEWEB)

Brandon, J.R.

1978-03-01

The potential for the transmission of parasites, such as Entamoeba sp., schistosomes, and nematodes such as Ascaris sp., to man through the use of sewage sludges as fertilizer is reviewed. The eggs of Ascaris have been found to be the most resistant of these parasites to normal sludge treatment methods. Results of studies on the effectiveness of heat and ionizing radiation treatments reported show that a treatment of 55/sup 0/C for 1 hour or more sufficiently reduces the number of viable Ascaris eggs in seeded sludge systems. An absorbed dose of 300 kilorads radiation is more than adequate for the same purpose. However, before an unequivocal statement can be made about the effectiveness of either of these treatments in reducing viable ova in real systems, certain qualifying factors must be investigated. There are conflicting reports on the radiation sensitivities of Ascaris eggs in different stages of development. Also, irradiation of composted sludge using an electron beam was unsuccessful in rendering all naturally-occurring Ascaris ova non-viable, even at 300 kilorads. The significant differences in radiation and heat sensitivities of Ascaris eggs in compost vs liquid systems points out the need to further investigate the effects of moisture levels on these sensitivities.

Parasites in soil/sludge systems

International Nuclear Information System (INIS)

Brandon, J.R.

1978-03-01

The potential for the transmission of parasites, such as Entamoeba sp., schistosomes, and nematodes such as Ascaris sp., to man through the use of sewage sludges as fertilizer is reviewed. The eggs of Ascaris have been found to be the most resistant of these parasites to normal sludge treatment methods. Results of studies on the effectiveness of heat and ionizing radiation treatments reported show that a treatment of 55 0 C for 1 hour or more sufficiently reduces the number of viable Ascaris eggs in seeded sludge systems. An absorbed dose of 300 kilorads radiation is more than adequate for the same purpose. However, before an unequivocal statement can be made about the effectiveness of either of these treatments in reducing viable ova in real systems, certain qualifying factors must be investigated. There are conflicting reports on the radiation sensitivities of Ascaris eggs in different stages of development. Also, irradiation of composted sludge using an electron beam was unsuccessful in rendering all naturally-occurring Ascaris ova non-viable, even at 300 kilorads. The significant differences in radiation and heat sensitivities of Ascaris eggs in compost vs liquid systems points out the need to further investigate the effects of moisture levels on these sensitivities

Enhanced heterotrophic denitrification: effect of dairy industry sludge acclimatization and operating conditions.

Science.gov (United States)

Akbari Shahabi, Zeinab; Naeimpoor, Fereshteh

2014-06-01

Heterotrophic denitrification of drinking water was enhanced by selection of an anoxic sludge taken from a dairy industry among the sludges taken from various industries, and the effect of carbon sources was examined. Acclimatization to high nitrate concentration was then carried out in a five-stage process. Considering removals of both nitrate and nitrite, the sludge taken from anoxic unit of Tehran Pegah dairy industry was shown to be the superior microbial culture, with ethanol as carbon source as compared to acetate. To enhance the rate of denitrification, acclimatization to nitrate (at 100, 200, 400, 800, and 1,600 mg N-NO3/L) was carried out in sequencing batch reactors over a 3-month period under anoxic condition, and comparisons were made between the performances of acclimated and non-acclimated sludges at each stage. It was found that acclimatization up to the fourth stage enhanced the specific denitrification rate to a high value of 29.6 mg N-NO3/h/g mixed liquor suspended solids (MLSS), with no significant nitrite accumulation. Additionally, the effect of initial pH (6, 6.5, 7, and 7.5) and carbon-to-nitrogen (C/N) ratio (1, 1.5, 2, and 3) on the performance of this final acclimated sludge was assessed, where initial pH of 7 and C/N ratio of 1.5 resulted in the best performances considering both nitrate and nitrite removal.

Bioremediation of storage tank bottom sludge by using a two-stage composting system: Effect of mixing ratio and nutrients addition.

Science.gov (United States)

Koolivand, Ali; Rajaei, Mohammad Sadegh; Ghanadzadeh, Mohammad Javad; Saeedi, Reza; Abtahi, Hamid; Godini, Kazem

2017-07-01

The effect of mixing ratio and nutrients addition on the efficiency of a two-stage composting system in removal of total petroleum hydrocarbons (TPH) from storage tank bottom sludge (STBS) was investigated. The system consisted of ten windrow piles as primary composting (PC) followed by four in-vessel reactors as secondary composting (SC). Various initial C/N/P and mixing ratios of STBS to immature compost (IC) were examined in the PC and SC for 12 and 6weeks, respectively. The removal rates of TPH in the two-stage system (93.72-95.24%) were higher than those in the single-stage one. Depending on the experiments, TPH biodegradation fitted to the first- and second-order kinetics with the rate constants of 0.051-0.334d -1 and 0.002-0.165gkg -1 d -1 , respectively. The bacteria identified were Pseudomonas sp., Bacillus sp., Klebsiella sp., Staphylococcus sp., and Proteus sp. The study verified that a two-stage composting system is effective in treating the STBS. Copyright © 2017 Elsevier Ltd. All rights reserved.

Textile wastewater treatment: aerobic granular sludge vs activated sludge systems.

Science.gov (United States)

Lotito, Adriana Maria; De Sanctis, Marco; Di Iaconi, Claudio; Bergna, Giovanni

2014-05-01

Textile effluents are characterised by high content of recalcitrant compounds and are often discharged (together with municipal wastewater to increase their treatability) into centralized wastewater treatment plants with a complex treatment scheme. This paper reports the results achieved adopting a granular sludge system (sequencing batch biofilter granular reactor - SBBGR) to treat mixed municipal-textile wastewater. Thanks to high average removals in SBBGR (82.1% chemical oxygen demand, 94.7% total suspended solids, 87.5% total Kjeldahl nitrogen, 77.1% surfactants), the Italian limits for discharge into a water receiver can be complied with the biological stage alone. The comparison with the performance of the centralized plant treating the same wastewater has showed that SBBGR system is able to produce an effluent of comparable quality with a simpler treatment scheme, a much lower hydraulic residence time (11 h against 30 h) and a lower sludge production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Supramolecular Organization of Nonstoichiometric Drug Hydrates: Dapsone

Directory of Open Access Journals (Sweden)

Doris E. Braun

2018-02-01

Full Text Available The observed moisture- and temperature dependent transformations of the dapsone (4,4′-diaminodiphenyl sulfone, DDS 0. 33-hydrate were correlated to its structure and the number and strength of the water-DDS intermolecular interactions. A combination of characterization techniques was used, including thermal analysis (hot-stage microscopy, differential scanning calorimetry and thermogravimetric analysis, gravimetric moisture sorption/desorption studies and variable humidity powder X-ray diffraction, along with computational modeling (crystal structure prediction and pair-wise intermolecular energy calculations. Depending on the relative humidity the hydrate contains between 0 and 0.33 molecules of water per molecule DDS. The crystal structure is retained upon dehydration indicating that DDS hydrate shows a non-stoichiometric (dehydration behavior. Unexpectedly, the water molecules are not located in structural channels but at isolated-sites of the host framework, which is counterintuitively for a hydrate with non-stoichiometric behavior. The water-DDS interactions were estimated to be weaker than water-host interactions that are commonly observed in stoichiometric hydrates and the lattice energies of the isomorphic dehydration product (hydrate structure without water molecules and (form III differ only by ~1 kJ mol−1. The computational generation of hypothetical monohydrates confirms that the hydrate with the unusual DDS:water ratio of 3:1 is more stable than a feasible monohydrate structure. Overall, this study highlights that a deeper understanding of the formation of hydrates with non-stoichiometric behavior requires a multidisciplinary approach including suitable experimental and computational methods providing a firm basis for the development and manufacturing of high quality drug products.

Two-stage pretreatment of excess sludge for electricity generation in microbial fuel cell.

Science.gov (United States)

Zhang, Yi; Zhao, Yang-Guo; Guo, Liang; Gao, Mengchun

2018-01-12

Thermophiles hydrolysis and acidogens fermentation were sequentially adopted to pretreat excess sludge for microbial fuel cell (MFC) electricity production. The results indicated that MFC fed with the thermophiles-acidogens pretreated sludge (MFC AB), reached a higher removal of ammonia nitrogen than the MFC fed with the heating hydrolysis and acidogens fermentation pretreated sludge (MFC NB). However, compared with the MFC AB, MFC NB presented a better performance for removal of soluble chemical oxygen demand (SCOD) (90.08%) and protein (82.42%). As for the electricity production, MFC NB obtained higher voltage of 0.632 V and maximum power density with 1.05 W/m 3 while MFC AB reached maximum voltage of 0.373 V and maximum power density of 0.58 W/m 3 . Bacterial 16S rRNA-based molecular microbial techniques showed that microbial communities on both MFC anode biofilms was diverse and different. The cooperation of fermentation bacteria and electricigen Shewanella baltica in the MFC NB may have contributed towards the improvement of electricity generation.

Impact of welan gum on tricalcium aluminate–gypsum hydration

International Nuclear Information System (INIS)

Ma Lei; Zhao Qinglin; Yao Chukang; Zhou Mingkai

2012-01-01

The retarding effect of welan gum on tricalcium aluminate–gypsum hydration, as a partial system of ordinary Portland cement (OPC) hydration, was investigated with several methods. The tricalcium aluminate–gypsum hydration behavior in the presence or absence of welan gum was researched by field emission gun scanning electron microscopy, X-ray diffraction and zeta potential analysis. Meanwhile, we studied the surface electrochemical properties and adsorption characteristics of welan gum by utilizing a zeta potential analyzer and UV–VIS absorption spectrophotometer. By adding welan gum, the morphology change of ettringite and retardation of hydration stages in tricalcium aluminate–gypsum system was observed. Moreover, we detected the adsorption behavior and zeta potential inversion of tricalcium aluminate and ettringite, as well as a rapid decrease in the zeta potential of tricalcium aluminate–gypsum system. The reduction on nucleation rate of ettringite and hydration activity of C 3 A was also demonstrated. Thus, through the adsorption effect, welan gum induces a retarding behavior in tricalcium aluminate–gypsum hydration. Highlights: ► Adsorption characteristics of welan gum on C 3 A and ettringite have been studied. ► C 3 A–gypsum hydration behavior and the hydration products are examined in L/S = 3. ► Welan gum retards the process of C 3 A–gypsum hydration. ► The addition of welan gum changes the nucleation growth of ettringite.

Co-conditioning and dewatering of chemical sludge and waste activated sludge.

Science.gov (United States)

Chang, G R; Liu, J C; Lee, D J

2001-03-01

The conditioning and dewatering behaviors of chemical and waste activated sludges from a tannery were studied. Capillary suction time (CST), specific resistance to filtration (SRF), and bound water content were used to evaluate the sludge dewatering behaviors. Zeta potentials were also measured. Experiments were conducted on each sludge conditioned and dewatered separately, and on the sludge mixed at various ratios. Results indicate that the chemical sludge was relatively difficult to be dewatered, even in the presence of polyelectrolyte. When the waste activated sludge was mixed with the chemical sludge at ratios of 1:1 and 2:1, respectively, the dewaterability of chemical sludge improved remarkably while the relatively better dewaterability of the waste activated sludge deteriorated only to a limited extent. As the mixing ratios became 4:1 and 8:1, the dewaterability of the mixed sludge was equal to that of the waste activated sludge. The optimal polyelectrolyte dosage for the mixed sludge was equal to or less than that of the waste activated sludge. It is proposed that the chemical sludges act as skeleton builders that reduce the compressibility of the mixed sludge whose dewaterability is enhanced. Bound water contents of sludge decreased at low polyelectrolyte dosage and were not significantly affected as polyelectrolyte dosage increased. Advantages and disadvantages of co-conditioning and dewatering chemical sludge and waste activated sludge were discussed.

Minimization of Excess Sludge in Activated Sludge Systems

Directory of Open Access Journals (Sweden)

Sayed Ali Reza Momeni

2006-01-01

Full Text Available The disposal of excess sludge from wastewater treatment plant represents a rising challenge in activated sludge processes. Hence, the minimization of excess sludge production was investigated by increasing the dissolved oxygen in aeration basin. Units of the pilot include: Primary sedimentation tank, aeration basin, secondary sedimentation tank, and return sludge tank. Volume of aeration basin is 360 l and influent flow rate is 90 L/h. Influent of pilot is taken from effluent of grit chamber of Isfahan's North Wastewater treatment plant. The experiments were done on different parts of pilot during the 5 month of study. Results show that increase of dissolved oxygen in aeration tank affect on decrease of excess sludge. Increase of dissolved oxygen from 0.5 to 4.5 mg/L resulted in 25% decrease of excess sludge. Variation of dissolved oxygen affect on settleability of sludge too. By increase of dissolved oxygen, SVI decreased and then increased. Value of 1-3 mg/L was the adequate range of dissolved oxygen by settleability of sludge and optimum range was 2-2.5 mg/L. It could be concluded by increasing of dissolved oxygen up to of 3 mg/L, sludge settleability significant decreased.

Dissociation heat of mixed-gas hydrate composed of methane and ethane

Energy Technology Data Exchange (ETDEWEB)

Hachikubo, A.; Nakagawa, R.; Kubota, D.; Sakagami, H.; Takahashi, N.; Shoji, H. [Kitami Inst. of Technology, Kitami (Japan)

2008-07-01

Formation and dissociation processes of natural gas hydrates in permafrost, marine and lake sediments are highly controlled by their thermal properties. Dissociation heat of gas hydrates can be estimated from phase equilibrium data using the Clausius-Clapeyron equation. However, this method is applicable for pure gas hydrate and at a temperature of 0 degrees Celsius. Direct calorimetric measurements on gas hydrates using a calorimeter have been developed to obtain thermal properties of gas hydrates, including dissociation heat and heat capacity. Studies have shown that a structure 2 gas hydrate appears in appropriate gas composition of methane and ethane. This paper investigated the effect of ethane concentration on dissociation heat of mixed-gas (methane and ethane) hydrate. Raman spectroscopy was used to confirm the appearance of a structure 2 gas hydrate. The paper identified the experimental procedure and discussed sample preparation, Raman spectroscopy, and calorimetric measurements. A schematic diagram of the calorimeter was also presented. It was concluded that in most cases, two stages of dissociation were found at the dissociation process. 15 refs., 6 figs.

Reconsideration on Hydration of Sodium Ion: From Micro-Hydration to Bulk Hydration

Science.gov (United States)

Yongquan, Zhou; Chunhui, Fang; Yan, Fang; Fayan, Zhu; Haiwen, Ge; Hongyan, Liu

2017-12-01

Micro hydration structures of the sodium ion, [Na(H2O) n ]+, n = 1-12, were probed by density functional theory (DFT) at B3LYP/aug-cc-pVDZ level in both gaseous and aqueous phase. The predicted equilibrium sodium-oxygen distance of 0.240 nm at the present level of theory. The four-, five- and six-coordinated cluster can transform from each other at the ambient condition. The analysis of the successive water binding energy and natural charge population (NBO) on Na+ clearly shows that the influence of Na+ on the surrounding water molecules goes beyond the first hydration shell with the hydration number of 6. The Car-Parrinello molecular dynamic simulation shows that only the first hydration sphere can be found, and the hydration number of Na+ is 5.2 and the hydration distance ( r Na-O) is 0.235 nm. All our simulations mentioned in the present paper show an excellent agreement with the diffraction result from X-ray scattering study.

Experimental and modeling investigation on structure H hydrate formation kinetics

International Nuclear Information System (INIS)

Mazraeno, M. Seyfi; Varaminian, F.; Vafaie sefti, M.

2013-01-01

Highlights: • Applying affinity model for the formation kinetics of sH hydrate and two stage kinetics. • Performing the experiments of hydrate formation of sH with MCP. • A unique path for the SH hydrate formation. - Abstract: In this work, the kinetics of crystal H hydrate and two stage kinetics formation is modeled by using the chemical affinity model for the first time. The basic idea is that there is a unique path for each experiment by which the crystallization process decays the affinity. The experiments were performed at constant temperatures of 274.15, 275.15, 275.65, 276.15 and 277.15 K. The initial pressure of each experiment is up to 25 bar above equilibrium pressure of sI. Methylcyclohexane (MCH), methylcyclopentane (MCP) and tert-butyl methyl ether (TBME) are used as sH former and methane is used as a help gas. The parameters of the affinity model (A r and t k ) are determined and the results show that the parameter of (A r )/(RT) has not a constant value when temperature changes in each group of experiments. The results indicate that this model can predict experimental data very well at several conditions

Sludge reduction in a small wastewater treatment plant by electro-kinetic disintegration.

Science.gov (United States)

Chiavola, Agostina; Ridolfi, Alessandra; D'Amato, Emilio; Bongirolami, Simona; Cima, Ennio; Sirini, Piero; Gavasci, Renato

2015-01-01

Sludge reduction in a wastewater treatment plant (WWTP) has recently become a key issue for the managing companies, due to the increasing constraints on the disposal alternatives. Therefore, all the solutions proposed with the aim of minimizing sludge production are receiving increasing attention and are tested either at laboratory or full-scale to evaluate their real effectiveness. In the present paper, electro-kinetic disintegration has been applied at full-scale in the recycle loop of the sludge drawn from the secondary settlement tank of a small WWTP for domestic sewage. After the disintegration stage, the treated sludge was returned to the biological reactor. Three different percentages (50, 75 and 100%) of the return sludge flow rate were subjected to disintegration and the effects on the sludge production and the WWTP operation efficiency evaluated. The long-term observations showed that the electro-kinetic disintegration was able to drastically reduce the amount of biological sludge produced by the plant, without affecting its treatment efficiency. The highest reduction was achieved when 100% return sludge flow rate was subjected to the disintegration process. The reduced sludge production gave rise to a considerable net cost saving for the company which manages the plant.

A novel rotation generator of hydrodynamic cavitation for waste-activated sludge disintegration.

Science.gov (United States)

Petkovšek, Martin; Mlakar, Matej; Levstek, Marjetka; Stražar, Marjeta; Širok, Brane; Dular, Matevž

2015-09-01

The disintegration of raw sludge is very important for enhancement of the biogas production in anaerobic digestion process as it provides easily degradable substrate for microorganisms to perform maximum sludge treatment efficiency and stable digestion of sludge at lower costs. In the present study the disintegration was studied by using a novel rotation generator of hydrodynamic cavitation (RGHC). At the first stage the analysis of hydrodynamics of the RGHC were made with tap water, where the cavitation extent and aggressiveness was evaluated. At the second stage RGHC was used as a tool for pretreatment of a waste-activated sludge (WAS), collected from wastewater treatment plant (WWTP). In case of WAS the disintegration rate was measured, where the soluble chemical oxygen demand (SCOD) and soluble Kjeldahl nitrogen were monitored and microbiological pictures were taken. The SCOD increased from initial 45 mg/L up to 602 mg/L and 12.7% more biogas has been produced by 20 passes through RGHC. The results were obtained on a pilot bioreactor plant, volume of 400 L. Copyright © 2015. Published by Elsevier B.V.

Evaluation of the influence of mechanical activation on physical and chemical properties of municipal solid waste incineration sludge.

Science.gov (United States)

Caprai, V; Florea, M V A; Brouwers, H J H

2018-06-15

Despite numerous studies concerning the application of by-products in the construction field, municipal solid waste incineration (MSWI) residues are not widely used as secondary building materials. In some European countries, washing treatment to the full bottom ash (BA) fraction (0-32 mm) is applied, isolating more contaminated particles, smaller than 0.063 mm. Therefore, a MWSI sludge is produced, having a high moisture content, and thus a limited presence of soluble species. In order to enhance its performance as building material, here, dry mechanical activation is applied on MSWI sludge. Thereafter, a reactivity comparison between reference BA and untreated and treated MSWI sludge is provided, evaluating their behaviour in the presence of cement and their pozzolanic activity. Moreover, the mechanical performances, as 25% substitution of Portland cement (PC) are assessed, based on the EN 450. Mechanical activation enhances MSWI sludge physically due to the improved particle morphology and packing. Chemically, the hydration degree of PC is enhanced by the MSWI sludge by ≈25%. The milling treatment proved to be beneficial to the residues performances in the presence of PC, providing 32% higher strength than untreated sample. Environmentally, the compliance with the unshaped material legislation is successfully verified, according to the Soil Quality Decree. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrasonic reduction of excess sludge from the activated sludge system

International Nuclear Information System (INIS)

Zhang Guangming; Zhang Panyue; Yang Jinmei; Chen Yanming

2007-01-01

Sludge treatment has long become the most challenging problem in wastewater treatment plants. Previous studies showed that ozone or chlorine effectively liquefies sludge into substrates for bio-degradation in the aeration tank, and thus reduces the excess sludge. This paper employs ultrasound to reduce the excess sludge from the sequential batch reactor (SBR) system. Partial sludge was disintegrated into dissolved substrates by ultrasound in an external sono-tank and was then returned to the SBR for bio-degradation. The results showed that ultrasound (25 kHz) effectively liquefied the sludge. The most effective conditions for sludge reduction were as following: sludge sonication ratio of 3/14, ultrasound intensity of 120 kW/kgDS, and sonication duration of 15 min. The amount of excess sludge was reduced by 91.1% to 17.8 mg/(L d); the organic content and settleability of sludge in the SBR were not impacted. The chemical oxygen demand (COD) removal efficiency was 81.1%, the total nitrogen (TN) removal efficiency was 17-66%, and high phosphorus concentration in the effluent was observed

Sludge Treatment Project Engineered Container Retrieval And Transfer System Preliminary Design Hazard Analysis Supplement 1

International Nuclear Information System (INIS)

Franz, G.R.; Meichle, R.H.

2011-01-01

This 'What/If' Hazards Analysis addresses hazards affecting the Sludge Treatment Project Engineered Container Retrieval and Transfer System (ECRTS) NPH and external events at the preliminary design stage. In addition, the hazards of the operation sequence steps for the mechanical handling operations in preparation of Sludge Transport and Storage Container (STSC), disconnect STSC and prepare STSC and Sludge Transport System (STS) for shipping are addressed.

Hydrate-CASM for modeling Methane Hydrate-Bearing Sediments

Science.gov (United States)

De La Fuente Ruiz, M.; Vaunat, J.; Marin Moreno, H.

2017-12-01

A clear understanding of the geomechanical behavior of methane hydrate-bearing sediments (MHBS) is crucial to assess the stability of the seafloor and submarine infrastructures to human and natural loading changes. Here we present the Hydrate-CASM, a new elastoplastic constitutive model to predict the geomechanical behavior of MHBS. Our model employs the critical state model CASM (Clay and Sand Model) because of its flexibility in describing the shape of the yield surface and its proven ability to predict the mechanical behavior of sands, the most commercially viable hydrate reservoirs. The model considers MHBS as a deformable elastoplastic continuum, and hydrate-related changes in the stress-strain behavior are predicted by a densification mechanism. The densification attributes the mechanical contribution of hydrate to; a reduction of the available void ratio; a decrease of the swelling line slope; and an increase of the volumetric yield stress. It is described by experimentally derived physical parameters except from the swelling slope coefficient that requires empirical calibration. The Hydrate-CASM is validated against published triaxial laboratory tests performed at different confinement stresses, hydrate saturations, and hydrate morphologies. During the validation, we focused on capturing the mechanical behavior of the host sediment and consider perturbations of the sediment's mechanical properties that could result from the sample preparation. Our model successfully captures the experimentally observed influence of hydrate saturation in the magnitude and trend of the stiffness, shear strength, and dilatancy of MHBS. Hence, we propose that hydrate-related densification changes might be a major factor controlling the geomechanical response of MHBS.

Heating value characteristics of sewage sludge: a comparative study of different sludge types

International Nuclear Information System (INIS)

Kim, Young-JU.; Kang, Hae-Ok.; Qureshi, T.I.

2005-01-01

Heating value characteristics of three different types of sludge, i.e. domestic sewage sludge, industrial sludge, and industrial + domestic sewage sludge were investigated. Industrial + domestic sewage sludge (thickened) showed the highest heating value (5040 kcal/kg) than other sludge types. This may be due to increased amount of organic matter presents in thickened sludge than de-watered sludge. A gradual increase in organic matter of the sludge was observed with the increase of the moisture contents. Heating value of the sludge having 60% moisture contents was found in the range between 924-1656 kcal/kg and this amount was higher than the minimum heating value (800 kcal/kg) required sustaining auto thermal combustion in sludge incineration process. Energy consumption requirement for pre drying sludge operations revealed that industrial sludge (de-watered) required the minimum cost (13 $/ton of sludge) to make it a sludge of fuel grade (60% W), while mixed sludge cost the highest amount for its pre-drying operations. (author)

The crucial effect of early-stage gelation on the mechanical properties of cement hydrates

Science.gov (United States)

Ioannidou, Katerina; Kanduč, Matej; Li, Lunna; Frenkel, Daan; Dobnikar, Jure; Del Gado, Emanuela

2016-07-01

Gelation and densification of calcium-silicate-hydrate take place during cement hydration. Both processes are crucial for the development of cement strength, and for the long-term evolution of concrete structures. However, the physicochemical environment evolves during cement formation, making it difficult to disentangle what factors are crucial for the mechanical properties. Here we use Monte Carlo and Molecular Dynamics simulations to study a coarse-grained model of cement formation, and investigate the equilibrium and arrested states. We can correlate the various structures with the time evolution of the interactions between the nano-hydrates during the preparation of cement. The novel emerging picture is that the changes of the physicochemical environment, which dictate the evolution of the effective interactions, specifically favour the early gel formation and its continuous densification. Our observations help us understand how cement attains its unique strength and may help in the rational design of the properties of cement and related materials.

Removal of actinides from dissolved ORNL MVST sludge using the TRUEX process

International Nuclear Information System (INIS)

Spencer, B.B.; Egan, B.Z.; Chase, C.W.

1997-07-01

Experiments were conducted to evaluate the transuranium extraction process for partitioning actinides from actual dissolved high-level radioactive waste sludge. All tests were performed at ambient temperature. Time and budget constraints permitted only two experimental campaigns. Samples of sludge from Melton Valley Storage Tank W-25 were rinsed with mild caustic (0.2 M NaOH) to reduce the concentrations of nitrates and fission products associated with the interstitial liquid. In one campaign, the rinsed sludge was dissolved in nitric acid to produce a solution containing total metal concentrations of ca. 1.8 M with a nitric acid concentration of ca. 2.9 M. About 50% of the dry mass of the sludge was dissolved. In the other campaign, the sludge was neutralized with nitric acid to destroy the carbonates, then leached with ca. 2.6 M NaOH for ca. 6 h before rinsing with the mild caustic. The sludge was then dissolved in nitric acid to produce a solution containing total metal concentrations of ca. 0.6 M with a nitric acid concentration of ca. 1.7 M. About 80% of the sludge dissolved. The dissolved sludge solution form the first campaign began gelling immediately, and a visible gel layer was observed after 8 days. In the second campaign, the solution became hazy after ca. 8 days, indicating gel formation, but did not display separated gel layers after aging for 20 days. Batch liquid-liquid equilibrium tests of both the extraction and stripping operations were conducted. Chemical analyses of both phases were used to evaluate the process. Evaluation was based on two metrics: the fraction of TRU elements removed from the dissolved sludge and comparison of the results with predictions made with the Generic TRUEX Model (GTM). The fractions of Eu, Pu, Cm, Th, and U species removed from aqueous solution in only one extraction stage were > 95% and were close to the values predicted by the GTM. Mercury was also found to be strongly extracted, with a one-stage removal of > 92%

Use of a water treatment sludge in a sewage sludge dewatering process

Science.gov (United States)

Górka, Justyna; Cimochowicz-Rybicka, Małgorzata; Kryłów, Małgorzata

2018-02-01

The objective of the research study was to determine whether a sewage sludge conditioning had any impact on sludge dewaterability. As a conditioning agent a water treatment sludge was used, which was mixed with a sewage sludge before a digestion process. The capillary suction time (CST) and the specific filtration resistance (SRF) were the measures used to determine the effects of a water sludge addition on a dewatering process. Based on the CST curves the water sludge dose of 0.3 g total volatile solids (TVS) per 1.0 g TVS of a sewage sludge was selected. Once the water treatment sludge dose was accepted, disintegration of the water treatment sludge was performed and its dewaterability was determined. The studies have shown that sludge dewaterability was much better after its conditioning with a water sludge as well as after disintegration and conditioning, if comparing to sludge with no conditioning. Nevertheless, these findings are of preliminary nature and future studies will be needed to investigate this topic.

Structured model of bacterial growth and tests with activated sludge in a one-stage and two-stage chemostat

NARCIS (Netherlands)

Harder, A.

1979-01-01

A kinetic model for a growing culture of micro-organisms was developed that correlated the biochemical structure of cells with quantitative physiological behaviour. The three-compartment model was adequate for simulation of continuous, batch and transient experiments with activated sludge fed on

Handling 78,000 drums of mixed-waste sludge

International Nuclear Information System (INIS)

Berry, J.B.; Harrington, E.S.; Mattus, A.J.

1991-01-01

The Oak Ridge Gaseous Diffusion Plant (now known as the Oak Ridge K-25 Site) closed two mixed-waste surface impoundments by removing the sludge and contaminated pond-bottom clay and attempting to process it into durable, nonleachable, concrete monoliths. Interim, controlled, above-ground storage included delisting the stabilized sludge from hazardous to nonhazardous and disposing of the delisted monoliths as Class 1 radioactive waste. Because of schedule constraints and process design and control deficiencies, ∼46,000 drums of material in various stages of solidification and ∼32,000 barrels of unprocessed sludge are stored. The abandoned treatment facility still contains ∼16,000 gal of raw sludge. Such storage of mixed waste does not comply with the Resource Conservation and Recovery Act (RCRA) guidelines. This paper describes actions that are under way to bring the storage of ∼78,000 drums of mixed waste into compliance with RCRA. Remediation of this problem by treatment to meet regulatory requirements is the focus of the discussion. 3 refs., 2 figs., 4 tabs

Energetic assessment of air-steam gasification of sewage sludge and of the integration of sewage sludge pyrolysis and air-steam gasification of char

International Nuclear Information System (INIS)

Gil-Lalaguna, N.; Sánchez, J.L.; Murillo, M.B.; Atienza-Martínez, M.; Gea, G.

2014-01-01

Thermo-chemical treatment of sewage sludge is an interesting option for recovering energy and/or valuable products from this waste. This work presents an energetic assessment of pyrolysis and gasification of sewage sludge, also considering the prior sewage sludge thermal drying and the gasification of the char derived from the pyrolysis stage. Experimental data obtained from pyrolysis of sewage sludge, gasification of sewage sludge and gasification of char (all of these performed in a lab-scale fluidized reactor) were used for the energetic calculations. The results show that the energy contained in the product gases from pyrolysis and char gasification is not enough to cover the high energy consumption for thermal drying of sewage sludge. Additional energy could be obtained from the calorific value of the pyrolysis liquid, but some of its properties must be improved facing towards its use as fuel. On the other hand, the energy contained in the product gas of sewage sludge gasification is enough to cover the energy demand for both the sewage sludge thermal drying and the gasification process itself. Furthermore, a theoretical study included in this work shows that the gasification efficiency is improved when the chemical equilibrium is reached in the process. - Highlights: • 4 MJ kg −1 for thermal drying of sewage sludge (SS) from 65 to 6.5 wt.% of moisture. • 0.15 MJ kg −1 for thermal decomposition of sewage sludge during fast pyrolysis. • Not enough energy in gases from SS pyrolysis and char gasification for thermal drying. • Enough energy in SS gasification gas for thermal drying and gasification process. • Gasification efficiency improves when equilibrium is reached in the process

Sustainable pyrolytic sludge-char preparation on improvement of closed-loop sewage sludge treatment: Characterization and combined in-situ application.

Science.gov (United States)

Jin, Zhengyu; Chang, Fengmin; Meng, Fanlin; Wang, Cuiping; Meng, Yao; Liu, Xiaoji; Wu, Jing; Zuo, Jiane; Wang, Kaijun

2017-10-01

Aiming at closed-loop sustainable sewage sludge treatment, an optimal and economical pyrolytic temperature was found at 400-450 °C considering its pyrolysis efficiency of 65%, fast cracking of hydrocarbons, proteins and lipids and development of aromatized porous structure. Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) tests demonstrated the development of adsorptive functional groups and crystallographic phases of adsorptive minerals. The optimal sludge-char, with a medium specific surface area of 39.6 m 2  g -1 and an iodine number of 327 mgI 2 g -1 , performed low heavy metals lixiviation. The application of sludge-char in raw sewage could remove 30% of soluble chemical oxygen demand (SCOD), along with an acetic acid adsorption capacity of 18.0 mg g -1 . The developed mesopore and/or macropore structures, containing rich acidic and basic functional groups, led to good biofilm matrices for enhanced microbial activities and improved autotrophic nitrification in anoxic stage of an A/O reactor through adsorbed extra carbon source, and hence achieved the total nitrogen (TN) removal up to 50.3%. It is demonstrated that the closed-loop sewage sludge treatment that incorporates pyrolytic sludge-char into in-situ biological sewage treatment can be a promising sustainable strategy by further optimization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials

International Nuclear Information System (INIS)

Zhang, Na; Li, Hongxu; Liu, Xiaoming

2016-01-01

Highlights: • Nanocrystalline regions in size of ∼5 nm were found in the amorphous C-A-S-H gel. • A hydration model was proposed to clarify the hydration mechanism. • The developed cementitious materials are environmentally acceptable. - Abstract: A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5 nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable.

Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials

Energy Technology Data Exchange (ETDEWEB)

Zhang, Na; Li, Hongxu [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Xiaoming, E-mail: liuxm@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China)

2016-08-15

Highlights: • Nanocrystalline regions in size of ∼5 nm were found in the amorphous C-A-S-H gel. • A hydration model was proposed to clarify the hydration mechanism. • The developed cementitious materials are environmentally acceptable. - Abstract: A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5 nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable.

Economic comparison of sludge irradiation and alternative methods of municipal sludge treatment

International Nuclear Information System (INIS)

Ahlstrom, S.B.; McGuire, H.E.

1977-11-01

The relative economics of radiation treatment and other sludge treatment processes are reported. The desirability of radiation treatment is assessed in terms of cost and the quality of the treated sludge product. The major conclusions of this study are: radiation treatment is a high-level disinfection process. Therefore, it should only be considered if high levels of disinfection are required for widespread reuse of the sludge; the handling, transporting and pathogen growback problems associated with disinfected wet sludge makes it less attractive for reuse than dry sludge; radiation of composted sludge produces a product of similar quality at less cost than any thermal treatment and/or flash drying treatment option for situations where a high degree of disinfection is required; and heavy metal concerns, especially cadmium, may limit the reuse of sludge despite high disinfection levels. It is recommended that radiation treatment of sludge, particularly dry sludge, continue to be studied. A sensitivity analysis investigating the optimal conditions under which sludge irradiation operates should be instigated. Furthermore, costs of adding sludge irradiation to existing sludge treatment schemes should be determined

Thermogravimetric study and kinetic analysis of dried industrial sludge pyrolysis.

Science.gov (United States)

Liu, Guangrui; Song, Huijuan; Wu, Jinhu

2015-07-01

Thermogravimetric experiments of two different industrial sludge samples were carried out with non-isothermal temperature programs. The results indicated that the pyrolysis process contains three obvious stages and the main decomposition reaction occurred in the range of 200-600°C. The distributed activation energy model (DAEM) was also proposed describing equally well the pyrolysis behavior of the samples. The calculated activation energy was ranged from 170 to 593kJ/mol and 125 to 756kJ/mol for SLYG (sludge sample from chemical fiber factory) and SQD (sludge sample from woody industry), respectively. The reliability of this model not only provided good fit for all experiments, but also allowed accurate extrapolations to relative higher heating rates. Besides, the FTIR measurement was also used to further understand the relationship between pyrolysis behavior and chemical structures for industrial sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dissolution of ORNL HLW sludge and partitioning of the actinides using the TRUEX process

International Nuclear Information System (INIS)

Spencer, B.B.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Dillow, T.A.

1997-01-01

Experiments were conducted to evaluate the transuranium extraction (TRUEX) process for partitioning actinides from actual dissolved high-level radioactive waste (HLW) sludge. Samples of sludge from melton Valley Storage Tank W-25 were rinsed with mild caustic (0.2 M NaOH) to reduce the concentrations of nitrates and fission products associated with the interstitial liquid. In one campaign the rinsed sludge was leached in nitric acid, and about 50% of the dry mass of the sludge was dissolved. The resulting solution contained total metal concentrations of ∼ 1.8 M with a nitric acid concentration of 2.9 M. In the other campaign the sludge was neutralized with nitric acid to destroy the carbonates, then leached with 2.6 M NaOH for ∼ 6 h before rinsing with the mild caustic. The sludge was then leached in nitric acid, and about 80% of the sludge dissolved. The resulting solution contained total metal concentrations of ∼ 0.6 M with a nitric acid concentration of 1.7 M. Chemical analyses of both phases were used to evaluate the process. Evaluation was based on two metrics: the fraction of TRU elements removed from the dissolved sludge and comparison of the results with predictions made with the Generic TRUEX Model (GTM). The fractions of Eu, Pu, Cm, Th and U species removed from aqueous solution in only one extraction stage were > 95% and were close to the values predicted by the GTM. Mercury was also found to be strongly extracted, with a one-stage removal of > 92%. In one test, vanadium appeared to be moderately extracted

Sewage sludge drying process integration with a waste-to-energy power plant.

Science.gov (United States)

Bianchini, A; Bonfiglioli, L; Pellegrini, M; Saccani, C

2015-08-01

Dewatered sewage sludge from Waste Water Treatment Plants (WWTPs) is encountering increasing problems associated with its disposal. Several solutions have been proposed in the last years regarding energy and materials recovery from sewage sludge. Current technological solutions have relevant limits as dewatered sewage sludge is characterized by a high water content (70-75% by weight), even if mechanically treated. A Refuse Derived Fuel (RDF) with good thermal characteristics in terms of Lower Heating Value (LHV) can be obtained if dewatered sludge is further processed, for example by a thermal drying stage. Sewage sludge thermal drying is not sustainable if the power is fed by primary energy sources, but can be appealing if waste heat, recovered from other processes, is used. A suitable integration can be realized between a WWTP and a waste-to-energy (WTE) power plant through the recovery of WTE waste heat as energy source for sewage sludge drying. In this paper, the properties of sewage sludge from three different WWTPs are studied. On the basis of the results obtained, a facility for the integration of sewage sludge drying within a WTE power plant is developed. Furthermore, energy and mass balances are set up in order to evaluate the benefits brought by the described integration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of the kinetic and stoichiometric constant in a conventional bioreactor of activated sludge, to scale

International Nuclear Information System (INIS)

Rodriguez Chaparro, Tatiana; Perez Navarrete, Eddie Albert; Vivas Mora, Eneydi

2003-01-01

The activated sludge process is the one of the most efficient process, when it comes to removal of organic matter. Implementing in the lab is quite easy, economic technically feasible, and simultaneously offers the possibility of using the results obtained in the lab to be applied in field by determining the kinetic and stoichiometric constants. The activated sludge system was designed, built and operated in the water quality lab, at the Military University in Bogota, Colombia. The bioreactor has an aeration chamber, a sedimentation tank and a feeding source with wastewater taken from a meat packing plant in Bogota. The research was carried out for 3 months, in two stages as follows: in the first stage and in order to obtain a high concentration of biomass the acclimatizing process was carried out. This step allows the bioreactor to run in a continuous flow. In the second stage, the bioreactor was taken in to operation and fed with the acclimated sludge at different sludge ages. This would allow us to determine the kinetics, and the stoichiometric constants. The bioreactor was run with a hydraulic retention time of 8 hours and for different sludge ages (5, 10, and 15 days). The system was monitored with a daily grab samples, and pH, temperature as well as the DBO 5 and suspended volatile solids were terminated

Irrigation port hydration in phacoemulsification surgery

Directory of Open Access Journals (Sweden)

Suzuki H

2018-01-01

Full Text Available Hisaharu Suzuki,1 Yoichiro Masuda,2 Yuki Hamajima,1 Hiroshi Takahashi3 1Department of Ophthalmology, Nippon Medical School Musashikosugi Hospital, Kawasaki City, Kanagawa, 2Department of Ophthalmology, The Jikei University, Katsushika Medical Center, Tokyo, 3Department of Ophthalmology, Nippon Medical School, Tokyo, Japan Background: In most cases, hydration is performed by water injection into the stromal tissue with a needle. The technique is simple, however it is sometimes troublesome.Purpose: We describe a simple technique for hydrating the corneal stroma in cataract surgery using an irrigation port.Patients and methods: The technique began by pushing the irrigation port against the corneal stroma for a few seconds during phacoemulsification, which generated edema in the corneal incision that subsequently prevented leakage. This procedure is called the hydration using irrigation port (HYUIP technique. A total of 60 eyes were randomized and placed in two groups, 30 eyes underwent surgeries using the HYUIP technique (HYUIP group and 30 eyes underwent surgeries without the HYUIP technique (control. The three points evaluated during each surgery included 1 the occurrence of anterior chamber collapse during the pulling out of the I/A tip after inserting the intraocular lens, 2 the need for conventional hydration, and 3 watertight completion at the end stage of surgery.Results: The anterior chamber collapse and the need for conventional hydration were significantly smaller in the HYUIP group compared to the control group. Regarding the self-sealing completion, no significant difference was observed between the two groups.Conclusion: The HYUIP technique is an effective method for creating self-sealing wound. In addition, this technique helps to prevent anterior chamber collapse. Keywords: cataract surgery, hydration, irrigation and aspiration, phacoemulsification, wound, self-sealing 

Biological sludge solubilisation for reduction of excess sludge production in wastewater treatment process.

Science.gov (United States)

Yamaguchi, T; Yao, Y; Kihara, Y

2006-01-01

A novel sludge disintegration system (JFE-SD system) was developed for the reduction of excess sludge production in wastewater treatment plants. Chemical and biological treatments were applied to disintegrate excess sludge. At the first step, to enhance biological disintegration, the sludge was pretreated with alkali. At the second step, the sludge was disintegrated by biological treatment. Many kinds of sludge degrading microorganisms integrated the sludge. The efficiency of the new sludge disintegration system was confirmed in a full-scale experiment. The JFE-SD system reduced excess sludge production by approximately 50% during the experimental period. The quality of effluent was kept at quite a good level. Economic analysis revealed that this system could significantly decrease the excess sludge treatment cost.

Highly efficient secondary dewatering of dewatered sewage sludge using low boiling point solvents.

Science.gov (United States)

He, Chao; Chena, Chia-Lung; Xu, Zhirong; Wang, Jing-Yuan

2014-01-01

Secondary dewatering of dewatered sludge is imperative to make conventional drying and incineration of sludge more economically feasible. In this study, a secondary dewatering of dewatered sludge with selected solvents (i.e. acetone and ethanol) followed by vacuum filtration and nature drying was investigated to achieve in-depth dewatering. After the entire secondary dewatering process, the sludge was shown to be odourless and the organic matter content was greatly retained. Increased mean particle size of sludge after solvent contact improved solid-liquid separation. With an acetone/sludge ratio of 3:1 (mL:g) in solvent contact and subsequent nature drying at ambient temperature after 24 h, the moisture content of sludge can be reduced to a level less than 20%. It is found that the polysaccharides were mainly precipitated by acetone, whereas the release ratios of protein and DNA were increased significantly as the added acetone volumes were elevated. During nature drying, accumulated evaporation rates of the sludge after solvent contact were 5-6 times higher than original dewatered sludge. Furthermore, sludge after acetone contact had better nature drying performance than ethanol. The two-stage dewatering involves solvent contact dewatering and solvent enhanced evaporation dewatering. Through selecting an appropriate solvent/sludge ratio as well as economical solvents and minimizing the solvent loss in a closed-pilot system, this dewatering process can be competitive in industrial applications. Therefore, this solvent-aided secondary dewatering is an energy-saving technology for effective in-depth dewatering of dewatered sludge and subsequent sludge utilization.

Contextual investigation of factors affecting sludge accumulation ...

African Journals Online (AJOL)

Pit latrines in slums areas of Uganda fill up faster than might be expected from some estimates owing to inappropriate use and failure to consider critical factors affecting sludge accumulation rates at the planning, design and construction stages. This study sought to investigate factors affecting filling rates of lined pit latrines ...

Photovoltaic's silica-rich waste sludge as supplementary cementitious material (SCM)

Energy Technology Data Exchange (ETDEWEB)

Quercia, G., E-mail: g.quercia@tue.nl [Materials innovation institute (M2i), Mekelweg 2, P.O. Box 5008, 2600 GA Delft (Netherlands); Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Putten, J.J.G. van der [Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Hüsken, G. [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany); Brouwers, H.J.H. [Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2013-12-15

Waste sludge, a solid recovered from wastewater of photovoltaic-industries, composes of agglomerates of nano-particles like SiO{sub 2} and CaCO{sub 3}. This sludge deflocculates in aqueous solutions into nano-particles smaller than 1 μm. Thus, this sludge constitutes a potentially hazardous waste when it is improperly disposed. Due to its high content of amorphous SiO{sub 2}, this sludge has a potential use as supplementary cementitious material (SCM) in concrete. In this study the main properties of three different samples of photovoltaic's silica-rich waste sludge (nSS) were physically and chemically characterized. The characterization techniques included: scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen physical adsorption isotherm (BET method), density by Helium pycnometry, particle size distribution determined by laser light scattering (LLS) and zeta-potential measurements by dynamic light scattering (DLS). In addition, a dispersability study was performed to design stable slurries to be used as liquid additives for the concrete production on site. The effects on the hydration kinetics of cement pastes by the incorporation of nSS in the designed slurries were determined using an isothermal calorimeter. A compressive strength test of standard mortars with 7% of cement replacement was performed to determine the pozzolanic activity of the waste nano-silica sludge. Finally, the hardened system was fully characterized to determine the phase composition. The results demonstrate that the nSS can be utilized as SCM to replace portion of cement in mortars, thereby decreasing the CO{sub 2} footprint and the environmental impact of concrete. -- Highlights: •Three different samples of PV nano-silica sludge (nSS) were fully characterized. •nSS is composed of agglomerates of nano-particles like SiO{sub 2} and CaCO{sub 3}. •Dispersability studies demonstrated that nSS agglomerates are broken to nano

An Economic comparison of sludge irradiation and alternative methods of municipal sludge treatment

Energy Technology Data Exchange (ETDEWEB)

Ahlstrom, S.B.; McGuire, H.E.

1977-11-01

The relative economics of radiation treatment and other sludge treatment processes are reported. The desirability of radiation treatment is assessed in terms of cost and the quality of the treated sludge product. The major conclusions of this study are: radiation treatment is a high-level disinfection process. Therefore, it should only be considered if high levels of disinfection are required for widespread reuse of the sludge; the handling, transporting and pathogen growback problems associated with disinfected wet sludge makes it less attractive for reuse than dry sludge; radiation of composted sludge produces a product of similar quality at less cost than any thermal treatment and/or flash drying treatment option for situations where a high degree of disinfection is required; and heavy metal concerns, especially cadmium, may limit the reuse of sludge despite high disinfection levels. It is recommended that radiation treatment of sludge, particularly dry sludge, continue to be studied. A sensitivity analysis investigating the optimal conditions under which sludge irradiation operates should be instigated. Furthermore, costs of adding sludge irradiation to existing sludge treatment schemes should be determined.

Free energy landscape and molecular pathways of gas hydrate nucleation

Energy Technology Data Exchange (ETDEWEB)

Bi, Yuanfei; Porras, Anna; Li, Tianshu, E-mail: tsli@gwu.edu [Department of Civil and Environmental Engineering, George Washington University, Washington DC 20052 (United States)

2016-12-07

Despite the significance of gas hydrates in diverse areas, a quantitative knowledge of hydrate formation at a molecular level is missing. The impediment to acquiring this understanding is primarily attributed to the stochastic nature and ultra-fine scales of nucleation events, posing a great challenge for both experiment and simulation to explore hydrate nucleation. Here we employ advanced molecular simulation methods, including forward flux sampling (FFS), p{sub B} histogram analysis, and backward flux sampling, to overcome the limit of direct molecular simulation for exploring both the free energy landscape and molecular pathways of hydrate nucleation. First we test the half-cage order parameter (H-COP) which we developed for driving FFS, through conducting the p{sub B} histogram analysis. Our results indeed show that H-COP describes well the reaction coordinates of hydrate nucleation. Through the verified order parameter, we then directly compute the free energy landscape for hydrate nucleation by combining both forward and backward flux sampling. The calculated stationary distribution density, which is obtained independently of nucleation theory, is found to fit well against the classical nucleation theory (CNT). Subsequent analysis of the obtained large ensemble of hydrate nucleation trajectories show that although on average, hydrate formation is facilitated by a two-step like mechanism involving a gradual transition from an amorphous to a crystalline structure, there also exist nucleation pathways where hydrate crystallizes directly, without going through the amorphous stage. The CNT-like free energy profile and the structural diversity suggest the existence of multiple active transition pathways for hydrate nucleation, and possibly also imply the near degeneracy in their free energy profiles among different pathways. Our results thus bring a new perspective to the long standing question of how hydrates crystallize.

Free energy landscape and molecular pathways of gas hydrate nucleation

International Nuclear Information System (INIS)

Bi, Yuanfei; Porras, Anna; Li, Tianshu

2016-01-01

Despite the significance of gas hydrates in diverse areas, a quantitative knowledge of hydrate formation at a molecular level is missing. The impediment to acquiring this understanding is primarily attributed to the stochastic nature and ultra-fine scales of nucleation events, posing a great challenge for both experiment and simulation to explore hydrate nucleation. Here we employ advanced molecular simulation methods, including forward flux sampling (FFS), p B histogram analysis, and backward flux sampling, to overcome the limit of direct molecular simulation for exploring both the free energy landscape and molecular pathways of hydrate nucleation. First we test the half-cage order parameter (H-COP) which we developed for driving FFS, through conducting the p B histogram analysis. Our results indeed show that H-COP describes well the reaction coordinates of hydrate nucleation. Through the verified order parameter, we then directly compute the free energy landscape for hydrate nucleation by combining both forward and backward flux sampling. The calculated stationary distribution density, which is obtained independently of nucleation theory, is found to fit well against the classical nucleation theory (CNT). Subsequent analysis of the obtained large ensemble of hydrate nucleation trajectories show that although on average, hydrate formation is facilitated by a two-step like mechanism involving a gradual transition from an amorphous to a crystalline structure, there also exist nucleation pathways where hydrate crystallizes directly, without going through the amorphous stage. The CNT-like free energy profile and the structural diversity suggest the existence of multiple active transition pathways for hydrate nucleation, and possibly also imply the near degeneracy in their free energy profiles among different pathways. Our results thus bring a new perspective to the long standing question of how hydrates crystallize.

Free energy landscape and molecular pathways of gas hydrate nucleation.

Science.gov (United States)

Bi, Yuanfei; Porras, Anna; Li, Tianshu

2016-12-07

Despite the significance of gas hydrates in diverse areas, a quantitative knowledge of hydrate formation at a molecular level is missing. The impediment to acquiring this understanding is primarily attributed to the stochastic nature and ultra-fine scales of nucleation events, posing a great challenge for both experiment and simulation to explore hydrate nucleation. Here we employ advanced molecular simulation methods, including forward flux sampling (FFS), p B histogram analysis, and backward flux sampling, to overcome the limit of direct molecular simulation for exploring both the free energy landscape and molecular pathways of hydrate nucleation. First we test the half-cage order parameter (H-COP) which we developed for driving FFS, through conducting the p B histogram analysis. Our results indeed show that H-COP describes well the reaction coordinates of hydrate nucleation. Through the verified order parameter, we then directly compute the free energy landscape for hydrate nucleation by combining both forward and backward flux sampling. The calculated stationary distribution density, which is obtained independently of nucleation theory, is found to fit well against the classical nucleation theory (CNT). Subsequent analysis of the obtained large ensemble of hydrate nucleation trajectories show that although on average, hydrate formation is facilitated by a two-step like mechanism involving a gradual transition from an amorphous to a crystalline structure, there also exist nucleation pathways where hydrate crystallizes directly, without going through the amorphous stage. The CNT-like free energy profile and the structural diversity suggest the existence of multiple active transition pathways for hydrate nucleation, and possibly also imply the near degeneracy in their free energy profiles among different pathways. Our results thus bring a new perspective to the long standing question of how hydrates crystallize.

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

Science.gov (United States)

Liu, Xinyuan; Han, Zeyu; Yang, Jie; Ye, Tianyi; Yang, Fang; Wu, Nan; Bao, Zhenbo

2018-02-01

Great amount of sewage sludge had been produced each year, which led to serious environmental pollution. Many new technologies had been developed recently, but they were hard to be applied in large scales. As one of the traditional technologies, anaerobic fermentation process was capable of obtaining bioenergy by biogas production under the functions of microbes. However, the anaerobic process is facing new challenges due to the low fermentation efficiency caused by the characteristics of sewage sludge itself. In order to improve the energy yield, the enhancement technologies including sewage sludge pretreatment process, co-digestion process, high-solid digestion process and two-stage fermentation process were widely studied in the literatures, which were introduced in this article.

Sewage sludge disintegration by high-pressure homogenization: a sludge disintegration model.

Science.gov (United States)

Zhang, Yuxuan; Zhang, Panyue; Ma, Boqiang; Wu, Hao; Zhang, Sheng; Xu, Xin

2012-01-01

High-pressure homogenization (HPH) technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree (DD(COD)), protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid (TS) content. The maximum DD(COD) of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DD(COD) = kNaPb was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure (P) was more significant than that of homogenization cycle number (N). The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.

Radiation disinfection of sewage sludge and composting of the irradiated sludge

International Nuclear Information System (INIS)

Hashimoto, Shoji; Nishimura, Koichi; Watanabe, Hiromasa; Kawakami, Waichiro

1985-01-01

In the radiation disinfected sewage sludge, its stabilization is necessary with the composting. In this disinfected sludge, there is no need of keeping it at high temperature at the cost of fermentation velocity. The fermentation velocity can thus be set to obtain its maximum value. In sewage sludge utilization of farm land, to prevent the contamination with pathogenic bacteria and the secondary pollution, the radiation disinfection of dehydrated sludge and the composting of the disinfected sludge have been studied. The disinfection effect when an electron accelerator is used for the radiation source is described. Then, the composting of the disinfected sludge is described in chemical kinetics of the microorganisms. (Mori, K.)

Sludge derived fuel technique of sewage sludge by oil vacuum evaporation drying

International Nuclear Information System (INIS)

Kim, Seokhwan; Lim, Byungran; Lee, Sookoo

2010-01-01

Sewage sludge contains high content of organic materials and its water content is also very high about 80% even after filtration process. Landfill as a sludge treatment methods can cause odor problem and leachate production which can derive the secondary contamination of soil and groundwater. The ocean dumping will be prohibited according to the London Convention and domestic stringent environmental regulation. Based on domestic agenda on organic sewage sludge treatment, the ocean disposal will be prohibited from 2012, thus alternative methods are demanded. Sludge derived fuel (SDF) technology can alleviate the emission of greenhouse gas and recover energy from sludge. For proper treatment and SDF production from sludge, the vacuum evaporation and immersion frying technology was adopted in this research. This technology dries moisture in sludge after mixing with oil such as Bunker C oil, waste oil or waste food oil etc. Mixing sludge and oil secures liquidity of organic sludge to facilitate handling throughout the drying process. The boiling temperature could be maintained low through vacuum condition in whole evaporation process. This study was performed to find the optimum operating temperature and pressure, the mixing ratio of sludge and oil. Finally, we could obtained SDF which moisture content was less than 5%, its heating value was over 4,500 kcal/ kg sludge. This heating value could satisfy the Korean Fuel Standard for the Recycle Products. Assessed from the perspective of energy balance and economic evaluation, this sludge drying system could be widely used for the effective sludge treatment and the production of SDF. (author)

Can hydrate dissolution experiments predict the fate of a natural hydrate system?

Energy Technology Data Exchange (ETDEWEB)

Hester, K.C.; Peltzer, E.T.; Dunk, R.M.; Walz, P.M.; Brewer, P.G. [Monterey Bay Aquarium Research Inst., Moss Landing, CA (United States); Dendy Sloan, E. [Colorado School of Mines, Golden, CO (United States). Center for Hydrate Research

2008-07-01

Gas hydrates are naturally occurring compounds found in permafrost regions and in oceans. In the natural environment, sufficient temperature and pressure conditions for hydrate formation exist over a significant portion of the ocean. However, in addition to pressure and temperature, the chemical potential of the gas in the hydrate must be equal to the surrounding waters. If the concentration of the gas in surrounding water is under-saturated with respect to the gas in the hydrate, the hydrate will dissolve to drive the system towards chemical equilibrium. This paper presented a dissolution study of exposed hydrate from outcrops at Barkley Canyon, located off Vancouver Island, British Columbia. A previous field experiment on synthetic methane hydrate samples had demonstrated that mass transfer controlled dissolution in under-saturated seawater. However, seafloor hydrate outcrops have been shown to have significant longevity compared to expected dissolution rates based upon convective boundary layer diffusion calculations. An in-situ dissolution experiment was performed on two distinct natural hydrate fabrics in order to help resolve this apparent disconnect between the dissolution rates of synthetic and natural hydrate. The paper presented a map of Barkley Canyon and discussed the field measurements and methods for the study. Exposed outcrops of gas hydrates were cored using a specially constructed stainless steel coring device and a hydraulic ram was located inside the corer. Hydrate samples were cored directly using the a manipulator arm and then injected into a sampling cell. The hydrate was then added to an open mesh exposure container, which allowed for exposure to ambient benthic currents with minimal disturbance. As well, in order to observe the slow dissolution of the hydrate in seawater at Barkley Canyon, time-lapse photography was employed. Last, the paper presented the results of the hydrate fabric porosities and hydrate dissolution rates. It was

Aortic-Radial Pulse Wave Velocity Ratio in End-stage Renal Disease Patients: Association with Age, Body Tissue Hydration Status, Renal Failure Etiology and Five Years of Hemodialysis.

Science.gov (United States)

Bia, Daniel; Valtuille, Rodolfo; Galli, Cintia; Wray, Sandra; Armentano, Ricardo; Zócalo, Yanina; Cabrera-Fischer, Edmundo

2017-03-01

The etiology of the end-stage renal disease (ESRD) and the hydration status may be involved in the arterial stiffening process observed in hemodialyzed patients. The ratio between carotid-femoral and carotid-radial pulse wave velocity (PWV ratio) was recently proposed to characterize the patient-specific stiffening process. to analyze: (1) the PWV-ratio in healthy and hemodialyzed subjects, analyzing potential changes associated to etiologies of the ESRD, (2) the PWV-ratio and hydration status using multiple-frequency bioimpedance and, (3) the effects of hemodialysis on PWV-ratio in a 5-year follow-up. PWV-ratio was evaluated in 151 patients differentiated by the pathology determining their ESRD. Total body fluid (TBF), intra and extra cellular fluid (ICF, ECF) were measured in 65 of these patients using bioelectrical-impedance. The association between arterial, hemodynamic or fluid parameters was analyzed. PWV-ratio was evaluated in a group of patients (n = 25) 5 years later (follow-up study). PWV-ratio increased in the ESRD cohort with respect to the control group (1.03 ± 0.23 vs. 1.31 ± 0.37; p hydration status, but not with the blood pressure. PWV-ratio could be considered a blood pressure-independent parameter, associated with the age and hydration status of the patient.

Electrical Conductive Mechanism of Gas Hydrate-Bearing Reservoirs in the Permafrost Region of Qilian Mountain

Science.gov (United States)

Peng, C.; Zou, C.; Tang, Y.; Liu, A.; Hu, X.

2017-12-01

In the Qilian Mountain, gas hydrates not only occur in pore spaces of sandstones, but also fill in fractures of mudstones. This leads to the difficulty in identification and evaluation of gas hydrate reservoir from resistivity and velocity logs. Understanding electrical conductive mechanism is the basis for log interpretation. However, the research is insufficient in this area. We have collected well logs from 30 wells in this area. Well logs and rock samples from DK-9, DK-11 and DK-12 wells were used in this study. The experiments including SEM, thin section, NMR, XRD, synthesis of gas hydrate in consolidated rock cores under low temperature and measurement of their resistivity and others were performed for understanding the effects of pore structure, rock composition, temperature and gas hydrate on conductivity. The results show that the porosity of reservoir of pore filling type is less than 10% and its clay mineral content is high. As good conductive passages, fractures can reduce resistivity of water-saturated rock. If fractures in the mudstone are filled by calcite, resistivity increases significantly. The resistivity of water-saturated rock at 2°C is twice of that at 18°C. The gas hydrate formation process in the sandstone was studied by resistivity recorded in real time. In the early stage of gas hydrate formation, the increase of residual water salinity may lead to the decrease of resistivity. In the late stage of gas hydrate formation, the continuity decrease of water leads to continuity increase of resistivity. In summary, fractures, rock composition, temperature and gas hydrate are important factors influencing resistivity of formation. This study is helpful for more accurate evaluation of gas hydrate from resistivity log. Acknowledgment: We acknowledge the financial support of the National Special Program for Gas Hydrate Exploration and Test-production (GZH201400302).

Sludge recovery apparatus

International Nuclear Information System (INIS)

Marmo, A.R.

1979-01-01

Sludge recovery machine comprising a hollow centrifuge, a vertical pipe for feeding in a liquid containing sludge and a sliding rake pressing against the internal wall of the centrifuge to dislodge and move the sludge, a power drive for spinning the centrifuge at high speed and a rotating drying table to take the sludge and dry it [fr

Fate of zinc in an electroplating sludge during electrokinetic treatments.

Science.gov (United States)

Liu, Shou-Heng; Wang, H Paul

2008-08-01

Chemical structure of zinc in the electrokinetic treatments of an electroplating sludge has been studied by in situ extended X-ray absorption fine structural (EXAFS) and X-ray absorption near edge structural (XANES) spectroscopies in the present work. The least-square fitted XANES spectra indicate that the main zinc compounds in the sludge were ZnCO(3) (75%), ZnOSiO(2) (17%) and Zn(OH)(2) (7%). Zinc in the sludge possessed a Zn-O bond distance of 2.07 A with a coordination number (CN) of 5. In the second shells, the bond distance of Zn-(O)-Si was 3.05 A (CN=2). An increase of Zn-(O)-Si (0.05 A) with a decrease of its CN (from 5 to <1) was found in the early stage of the electrokinetic treatment. Prolong the electrokinetic treatment time to 180 min, about 34% of Zn(II) was dissolved into the aqueous phase and about 68% of Zn(II) in the sludge (or 23% of total zinc) was migrated to the cathode under the electric field (5 V cm(-1)). The dissolution and electromigration rates of Zn(II) in the sludge were 1.0 and 0.6 mmol h(-1)g(-1) sludge, respectively during the electrokinetic treatment. This work also exemplifies the utilization of in situ EXAFS and XANES for revealing speciation and possible reaction pathways during the course of zinc recycling from the sludge by electrokinetic treatments.

Effects of Sludge Dry Solid Content and Residual Bulking Agents on Volatile Solids Reduction Using Eisenia foetida

Directory of Open Access Journals (Sweden)

Mohammad ali Abdoli

2009-06-01

Full Text Available In the first stage of this study, the compound effects of sludge dry solid content and residual bulking agent type (paper, saw dust, straw mixed with activated sludge (10, 15, and 20% dry solids on volatile solids (V.S. reduction were investigated using Eisenia foetida in pilot scale experiments with batches of fifty earthworms in each of the 10 experimental treatments over a period of 10 weeks. The maximum V.S. reduction was attained in the mixture of sludge and paper, with a D.S. of 15% (0.42 ± 0.03 % day-1 while the minimum V.S. reduction was achieved in the mixture of sludge and straw, with a D.S. of 10% (0.26 ± 0.01 % day-1. In the second stage, the survival of Eisenia foetida in the anaerobic sewage sludge was investigated. In the unmixed raw anaerobic sludge, all the earthworms died during the first 9 weeks of the study period due to acute toxicity. From week 10, however, their survival rate improved so that by week 12 when toxicity reduced to 25.40%, they completely survived. This is while in the mixture of anaerobic sludge with paper (D.S. 15%, 100% of the earthworms survived from week 8 after the volatile solids reduced to 20.42% and 17.40%.

Excess sludge reduction in activated sludge processes by integrating ultrasound treatment

International Nuclear Information System (INIS)

Perez-Elvira, S.; Fdz-Polanco, M.; Plaza, F. I.; Garralon, G.; Fdz-Polanco, F.

2009-01-01

Biological sludge produced in the activated sludge process can be minimised modifying the water line, the sludge line or the final disposal strategy. Selecting the water line the general idea is to reduce the sludge producing the yield coefficient by means of the called lysis cryptic growth process. The main techniques referenced in literature are onization, chlorination and chemical and heat treatment. Ultrasounds are widely used to increase anaerobic biodegradability but are not reported as system to control excess sludge production. (Author)

Results of ultrasonic disintegration of sewage sludge in practice; Ergebnisse des Praxiseinsatzes der Schlammdesintegration mittels Ultraschall

Energy Technology Data Exchange (ETDEWEB)

Friedrich, E. [IWE-Ingenieurgesellschaft fuer Wasser und Entsorgung mbH, Radebeul (Germany); Friedrich, H. [Fraunhofer-Institut fuer Keramische Technologien und Sinterwerkstoffe (IKTS), Dresden (Germany); Hielscher, H. [Hielscher GmbH, Teltow (Germany)

1999-07-01

Using high-performance ultrasonic sludge disintegration in different stages of sewage and sludge treatment is found to be an innovative approach for reducing the accruing amounts of sewage sludge in terms of both mass and volume. By means of practical tests with sludge disintegration at sewage treatment plants, its effects are demonstrated. (orig.) [German] Der Einsatz einer Hochleistungs-Ultraschalltechnik zur Schlammdesintegration in verschiedenen Stufen der Abwasser- und Schlammbehandlung zeigt sich als innovativer Loesungsweg zur weitestgehenden massenmaessigen sowie volumenmaessigen Minimierung des Klaerschlammanfalles. An Hand von Einsatzerprobungen der Desintegration in der Klaeranlagenpraxis werden die Effekte der Desintegration vorgestellt. (orig.)

Environmental evaluation of sewage sludge co-combustion in a pilot FBC

Energy Technology Data Exchange (ETDEWEB)

M. Helena Lopes; P. Abelha; I. Cabrita; J.F.Santos Oliveira; I. Gulyurtlu [INETI/DEECA, Lisbon (Portugal)

2003-07-01

This paper presents a comparison of combustion of coal alone with that of a mixture of coal with sewage sludge with respect to flue gas emissions, the behaviour of heavy metals and potential environmental consequences of disposal of ashes produced. Co-combustion with sludge did not result in greater NOx, SO{sub 2}, HCl and CO emissions and the use of air staging and the addition of limestone proved to be effective to reduce NOx and SO{sub 2}. The mixing of sludge gave rise to an increase in amounts of heavy metals released, especially for Cd, Pb and Hg. However, as they were associated with particles greater than 1 {micro}m, the application of efficient flue gas treatment devices could decrease their emissions to the atmosphere. Metals were essentially retained in ashes captured in the bed and in the cyclones and most of the Hg was adsorbed in fly ashes that contained unburned carbon. The leachability of metals and organic matter present in the sludge decreased with combustion. The evaluation of the acid neutralization capacity (ANC) showed that ashes became more resistant to acidification than the parent sludge. Globally, this study concludes that the implication of the combustion of sludge is that it can reduce the negative impact on the environment compared with the traditional direct use of sludge in soils. 22 refs., 4 figs., 5 tabs.

Gas hydrates

Digital Repository Service at National Institute of Oceanography (India)

Ramprasad, T.

, not all of them are white like snow. Some hydrates from the deep Gulf of Mexico are richly colored in shades of yellow, orange, or even red. The ice-like masses are beautiful, and contrast with the dull gray of deep sea muds. Hydrates from the Blake... volcanoes and associated gas hydrates: Marine Geology, v. 167, p. 29-42. Milkov, A.V. and R. Sassen, 2001a, Estimate of gas hydrate resource, northwestern Gulf of Mexico continental slope: Marine Geology, v. 179, pp. 71-83. Milkov, A.V., Sassen, R...

Measurements of gas permeability and non-Darcy flow in gas-water-hydrate systems

Energy Technology Data Exchange (ETDEWEB)

Ersland, G.; Husebo, J.; Graue, A.; Kvamme, B. [Bergen Univ., Bergen (Norway). Dept. of Physics and Technology; Baldwin, B. [Green Country Petrophysics LLC, Dewey, OK (United States); Stevens, J.; Howard, J. [ConocoPhillips, OK (United States)

2008-07-01

Storage of carbon dioxide (CO{sub 2}) in natural gas hydrate reservoirs may offer stable long-term storage of a greenhouse gas while benefiting from methane production, without requiring heat. By exposing hydrate to a thermodynamically preferred hydrate former, CO{sub 2}, the hydrate may be maintained macroscopically in the solid state and retain the stability of the formation. However, there is concern over the flow capacity in such reservoirs. This depends on several factors, notably thermodynamic destabilization of hydrate in small pores due to capillary effects; the presence of liquid channels separating the hydrate from the mineral surfaces; and, the connectivity of gas or liquid filled pores and channels. This paper described a technique for measuring gas permeability in gas-water-hydrate systems. It reported on several experiments that measured gas permeability during stages of hydrate growth in sandstone core plugs. Interactions between minerals and surrounding molecules were also discussed. The formation of methane hydrate in porous media was monitored and quantified with magnetic resonance imaging (MRI). MRI images of hydrate growth within the porous rock were provided along with measurements of gas permeability and non-Darcy flow effects at various hydrate saturations. Gas permeability was measured at steady state flow of methane through the hydrate-bearing core sample. Significant gas permeability was recorded for porous sandstone even when hydrates occupied up to 60 per cent of the pore space. It was concluded that MRI imaging can be used effectively to map and quantify hydrate saturation in sandstone core plugs. 27 refs., 2 tabs., 10 figs.

Shifting Focus: From Hydration for Performance to Hydration for Health.

Science.gov (United States)

Perrier, Erica T

2017-01-01

Over the past 10 years, literature on hydration biomarkers has evolved considerably - from (de)hydration assessment towards a more global definition of biomarkers of hydration in daily life. This shift in thinking about hydration markers was largely driven by investigating the differences that existed between otherwise healthy individuals whose habitual, ad-libitum drinking habits differ, and by identifying physiological changes in low-volume drinkers who subsequently increase their water intake. Aside from obvious differences in urinary volume and concentration, a growing body of evidence is emerging that links differences in fluid intake with small, but biologically significant, differences in vasopressin (copeptin), glomerular filtration rate, and markers of metabolic dysfunction or disease. Taken together, these pieces of the puzzle begin to form a picture of how much water intake should be considered adequate for health, and represent a shifting focus from hydration for performance, toward hydration for health outcomes. This narrative review outlines the key areas of research in which the global hydration process - including water intake, urinary hydration markers, and vasopressin - has been associated with health outcomes, focusing on kidney and metabolic endpoints. It will also provide a commentary on how various hydration biomarkers may be used in hydration for health assessment. Finally, if adequate water intake can play a role in maintaining health, how might we tell if we are drinking enough? Urine output is easily measured, and can take into account differences in daily physical activity, climate, dietary solute load, and other factors that influence daily water needs. Today, targets have been proposed for urine osmolality, specific gravity, and color that may be used by researchers, clinicians, and individuals as simple indicators of optimal hydration. However, there remain a large number of incomplete or unanswered research questions regarding the

Failure of cement hydrates: freeze-thaw and fracture

Science.gov (United States)

Ioannidou, Katerina; Del Gado, Emanuela; Ulm, Franz-Josef; Pellenq, Roland

Mechanical and viscoelastic behavior of concrete crucially depends on cement hydrates, the ``glue'' of cement. Even more than the atomistic structure, the mesoscale amorphous texture of cement hydrates over hundreds of nanometers plays a crucial role for material properties. We use simulations that combine information of the nano-scale building units of cement hydrates and on their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles.Our mesoscale model was able to reconcile different experimental results ranging from small-angle neutron scattering, SEM, adsorption/desorption of N2, and water to nanoindentation and gain the new fundamental insights into the microscopic origin of the properties measured. Our results suggest that heterogeneities developed during the early stages of hydration persist in the structure of C-S-H, impacting the rheological and mechanical performance of the hardened cement paste. In this talk I discuss recent investigation on failure mechanism at the mesoscale of hardened cement paste such as freeze-thaw and fracture. Using correlations between local volume fractions and local stress we provide a link between structural and mechanical heterogeneities during the failure mechanisms.

Preliminary technical data summary for the Defense Waste Processing Facility, Stage 1

International Nuclear Information System (INIS)

1980-09-01

This Preliminary Technical Data Summary presents the technical basis for design of Stage 1 of the Staged Defense Waste Processing Facility (DWPF), a process to efficiently immobilize the radionuclides in Savannah River Plant (SRP) high-level liquid waste. The radionuclides in SRP waste are present in sludge that has settled to the bottom of waste storage tanks and in crystallized salt and salt solution (supernate). Stage 1 of the DWPF receives washed, aluminum dissolved sludge from the waste tank farms and immobilizes it in a borosilicate glass matrix. The supernate is retained in the waste tank farms until completion of Stage 2 of the DWPF at which time it filtered and decontaminated by ion exchange in the Stage 2 facility. The decontaminated supernate is concentrated by evaporation and mixed with cement for burial. The radioactivity removed from the supernate is fixed in borosilicate glass along with the sludge. This document gives flowsheets, material, and curie balances, material and curie balance bases, and other technical data for design of the Stage 1 DWPF

Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance.

Science.gov (United States)

Jin, Lingyun; Zhang, Guangming; Zheng, Xiang

2015-02-01

A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge disintegration can destroy the sludge structure and cell wall, so as change the sludge floc structure and moisture distribution, thus affecting the dewatering performance of sludge. In this article, the disintegration methods were ultrasound treatment, K2FeO4 oxidation and KMnO4 oxidation. The degree of disintegration (DDCOD), sludge moisture distribution and the final water content of sludge cake after centrifuging were measured. Results showed that three disintegration methods were all effective, and K2FeO4 oxidation was more efficient than KMnO4 oxidation. The content of free water increased obviously with K2FeO4 and KMnO4 oxidations, while it decreased with ultrasound treatment. The changes of free water and interstitial water were in the opposite trend. The content of bounding water decreased with K2FeO4 oxidation, and increased slightly with KMnO4 oxidation, while it increased obviously with ultrasound treatment. The water content of sludge cake after centrifuging decreased with K2FeO4 oxidation, and did not changed with KMnO4 oxidation, but increased obviously with ultrasound treatment. In summary, ultrasound treatment deteriorated the sludge dewaterability, while K2FeO4 and KMnO4 oxidation improved the sludge dewaterability. Copyright © 2014. Published by Elsevier B.V.

Impacts of Hydrate Distribution on the Hydro-Thermo-Mechanical Properties of Hydrate-Bearing Sediments

Science.gov (United States)

Dai, S.; Seol, Y.

2015-12-01

In general, hydrate makes the sediments hydraulically less conductive, thermally more conductive, and mechanically stronger; yet the dependency of these physical properties on hydrate saturation varies with hydrate distribution and morphology. Hydrate distribution in sediments may cause the bulk physical properties of their host sediments varying several orders of magnitude even with the same amount of hydrate. In natural sediments, hydrate morphology is inherently governed by the burial depth and the grain size of the host sediments. Compare with patchy hydrate, uniformly distributed hydrate is more destructive to fluid flow, yet leads to higher gas and water permeability during hydrate dissociation due to the easiness of forming percolation paths. Water and hydrate have similar thermal conductivity values; the bulk thermal conductivity of hydrate-bearing sediments depends critically on gas-phase saturation. 60% of gas saturation may result in evident thermal conductivity drop and hinder further gas production. Sediments with patchy hydrate yield lower stiffness than that with cementing hydrate but higher stiffness than that with pore filling and loading bearing hydrate. Besides hydrate distribution, the stress state and loading history also play an important role in the mechanical behavior of hydrate-bearing sediments.

Performance of a system with full- and pilot-scale sludge drying reed bed units treating septic tank sludge in Brazil.

Science.gov (United States)

Calderón-Vallejo, Luisa Fernanda; Andrade, Cynthia Franco; Manjate, Elias Sete; Madera-Parra, Carlos Arturo; von Sperling, Marcos

2015-01-01

This study investigated the performance of sludge drying reed beds (SDRB) at full- and pilot-scale treating sludge from septic tanks in the city of Belo Horizonte, Brazil. The treatment units, planted with Cynodon spp., were based on an adaptation of the first-stage of the French vertical-flow constructed wetland, originally developed for treating sewage. Two different operational phases were investigated; in the first one, the full-scale unit was used together with six pilot-scale columns in order to test different feeding strategies. For the second phase, only the full-scale unit was used, including a recirculation of the filtered effluent (percolate) to one of the units of the French vertical wetland. Sludge application was done once a week emptying a full truck, during 25 weeks. The sludge was predominantly diluted, leading to low solids loading rates (median values of 18 kgTS m(-2) year(-1)). Chemical oxygen demand removal efficiency in the full-scale unit was reasonable (median of 71%), but the total solids removal was only moderate (median of 44%) in the full-scale unit without recirculation. Recirculation did not bring substantial improvements in the overall performance. The other loading conditions implemented in the pilot columns also did not show statistically different performances.

Preliminary technical data summary defense waste processing facility stage 2

International Nuclear Information System (INIS)

1980-12-01

This Preliminary Technical Data Summary presents the technical basis for design of Stage 2 of the Staged Defense Waste Processing Facility (DWPF). Process changes incorporated in the staged DWPF relative to the Alternative DWPF described in PTDS No. 3 (DPSTD-77-13-3) are the result of ongoing research and development and are aimed at reducing initial capital investment and developing a process to efficiently immobilize the radionuclides in Savannah River Plant (SRP) high-level liquid waste. The radionuclides in SRP waste are present in sludge that has settled to the bottom of waste storage tanks and in crystallized salt and salt solution (supernate). Stage 1 of the DWPF receives washed, aluminum dissolved sludge from the waste tank farms and immobilizes it in a borosilicate glass matrix. The supernate is retained in the waste tank farms until completion of Stage 2 of the DWPF at which time it is filtered and decontaminated by ion exchange in the Stage 2 facility. The decontaminated supernate is concentrated by evaporation and mixed with cement for burial. The radioactivity removed from the supernate is fixed in borosilicate glass along with the sludge. This document gives flowsheets, material and curie balances, material and curie balance bases, and other technical data for design of Stage 2 of the DWPF. Stage 1 technical data are presented in DPSTD-80-38

Radon exhalation of hardening concrete: monitoring cement hydration and prediction of radon concentration in construction site.

Science.gov (United States)

Kovler, Konstantin

2006-01-01

The unique properties of radon as a noble gas are used for monitoring cement hydration and microstructural transformations in cementitious system. It is found that the radon concentration curve for hydrating cement paste enclosed in the chamber increases from zero (more accurately - background) concentrations, similar to unhydrated cement. However, radon concentrations developed within 3 days in the test chamber containing cement paste were approximately 20 times higher than those of unhydrated cement. This fact proves the importance of microstructural transformations taking place in the process of cement hydration, in comparison with cement grain, which is a time-stable material. It is concluded that monitoring cement hydration by means of radon exhalation method makes it possible to distinguish between three main stages, which are readily seen in the time dependence of radon concentration: stage I (dormant period), stage II (setting and intensive microstructural transformations) and stage III (densification of the structure and drying). The information presented improves our understanding of the main physical mechanisms resulting in the characteristic behavior of radon exhalation in the course of cement hydration. The maximum value of radon exhalation rate observed, when cement sets, can reach 0.6 mBq kg(-1) s(-1) and sometimes exceeds 1.0 mBq kg(-1) s(-1). These values exceed significantly to those known before for cementitious materials. At the same time, the minimum ventilation rate accepted in the design practice (0.5 h(-1)), guarantees that the concentrations in most of the cases will not exceed the action level and that they are not of any radiological concern for construction workers employed in concreting in closed spaces.

Parasites in soil/sludge systems

International Nuclear Information System (INIS)

Brandon, J.R.

1978-01-01

Studies reported herein have shown that a treatment of 55 0 C for 1 hour or more sufficiently reduces the number of viable Ascaris eggs in seeded sludge systems. An absorbed dose of 300 kilorads γ radiation is more than adequate for the same purpose. However, before an unequivocal statement can be made about the effectiveness of either of these treatments in reducing viable ova in real systems, certain qualifying factors must be investigated. There are conflicting reports on the radiation sensitivities of Ascaris eggs in different stages of development. Also, irradiation of composted sludge using an electron-beam (which, for all practical purposes, is equivalent to γ irradiation for a given absorbed dose) was unsuccessful in rendering all naturally-occurring Ascaris ova non-viable, even at 300 kilorads. The significant differences in radiation and heat sensitivities of Ascaris eggs in compost vs liquid systems points out the need to further investigate the effects of moisture levels on these sensitivities

Handling 78,000 drums of mixed-waste sludge

International Nuclear Information System (INIS)

Berry, J.B.; Gilliam, T.M.; Harrington, E.S.; Youngblood, E.L.; Baer, M.B.

1991-01-01

The Oak Ridge Gaseous Diffusion Plant (now know as the Oak Ridge K-25 Site) prepared two mixed-waste surface impoundments for closure by removing the sludge and contaminated pond-bottom clay and attempting to process it into durable, nonleachable, concrete monoliths. Interim, controlled, above-ground storage of the stabilized waste was planned until final disposition. The strategy for disposal included delisting the stabilized pond sludge from hazardous to nonhazardous and disposing of the delisted monoliths as radioactive waste. Because of schedule constraints and process design and control deficiencies, ∼46,000 drums of material in various stages of solidification and ∼32,000 drums of unprocessed sludge are presently being stored. In addition, the abandoned treatment facility still contains ∼16,000 gal of raw sludge. Such conditions do not comply with the requirements set forth by the Resource Conservation and Recovery Act (RCRA) for the storage of listed waste. Various steps are being taken to bring the storage of ∼78,000 drums of mixed waste into compliance with RCRA. This paper (1) reviews the current situation, (2) discusses the plan for remediation of regulatory noncompliances, including decanting liquid from stabilized waste and dewatering untreated waste, and (3) provides an assessment of alternative raw-waste treatment processes. 1 ref., 6 figs., 2 tabs

The role and control of sludge age in biological nutrient removal activated sludge systems.

Science.gov (United States)

Ekama, G A

2010-01-01

The sludge age is the most fundamental and important parameter in the design, operation and control of biological nutrient removal (BNR) activated sludge (AS) systems. Generally, the better the effluent and waste sludge quality required from the system, the longer the sludge age, the larger the biological reactor and the more wastewater characteristics need to be known. Controlling the reactor concentration does not control sludge age, only the mass of sludge in the system. When nitrification is a requirement, sludge age control becomes a requirement and the secondary settling tanks can no longer serve the dual purpose of clarifier and waste activated sludge thickeners. The easiest and most practical way to control sludge age is with hydraulic control by wasting a defined proportion of the reactor volume daily. In AS plants with reactor concentration control, nitrification fails first. With hydraulic control of sludge age, nitrification will not fail, rather the plant fails by shedding solids over the secondary settling tank effluent weirs.

PROGRESS WITH K BASINS SLUDGE RETRIEVAL STABILIZATION & PACKAGING AT THE HANFORD NUCLEAR SITE

Energy Technology Data Exchange (ETDEWEB)

KNOLLMEYER, P.M.; PHILLIPS, C; TOWNSON, P.S.

2006-01-30

This paper shows how Fluor Hanford and BNG America have combined nuclear plant skills from the U.S. and the U.K. to devise methods to retrieve and treat the sludge that has accumulated in K Basins at the Hanford Site over many years. Retrieving the sludge is the final stage in removing fuel and sludge from the basins to allow them to be decontaminated and decommissioned, so as to remove the threat of contamination of the Columbia River. A description is given of sludge retrieval using vacuum lances and specially developed nozzles and pumps into Consolidation Containers within the basins. The special attention that had to be paid to the heat generation and potential criticality issues with the irradiated uranium-containing sludge is described. The processes developed to re-mobilize the sludge from the Consolidation Containers and pump it through flexible and transportable hose-in-hose piping to the treatment facility are explained with particular note made of dealing with the abrasive nature of the sludge. The treatment facility, housed in an existing Hanford building, is described, and the uranium-corrosion and grout packaging processes explained. The uranium corrosion process is a robust, tempered process very suitable for dealing with a range of differing sludge compositions. Optimization and simplification of the original sludge corrosion process design is described and the use of transportable and reusable equipment is indicated. The processes and techniques described in the paper are shown to have wide applicability to nuclear cleanup.

Radioactivity in sludge: tank cleaning procedures and sludge disposal

International Nuclear Information System (INIS)

Bradley, D.A.

1995-01-01

In the oil and gas industry management of alpha-active sludge is made more complex by the presence of hydrocarbons and heavy metals. This presentation discusses the origin of radioactivity in sludge, management of risk in terms of safe working procedures, storage and possible disposal options. The several options will generally involve aspects of dilution or of concentration; issues to be discussed will include sludge farming, bioremediation and incineration. (author)

Sludge pretreatment chemistry evaluation: Enhanced sludge washing separation factors

International Nuclear Information System (INIS)

Colton, N.G.

1995-03-01

This report presents the work conducted in Fiscal Year 1994 by the Sludge Pretreatment Chemistry Evaluation Subtask for the Tank Waste Remediation System (TWRS) Tank Waste Treatment Science Task. The main purpose of this task, is to provide the technical basis and scientific understanding to support TWRS baseline decisions and actions, such as the development of an enhanced sludge washing process to reduce the volume of waste that will require high-level waste (HLW) vitrification. One objective within the Sludge Pretreatment Chemistry Evaluation Subtask was to establish wash factors for various SST (single-shell tank) sludges. First, analytical data were compiled from existing tank waste characterization reports. These data were summarized on tank-specific worksheets that provided a uniform format for reviewing and comparing data, as well as the means to verify whether the data set for each tank was complete. Worksheets were completed for 27 SST wastes. The analytical water wash data provided tank-specific information about the fraction of each component that dissolves with water, i.e., an estimate of tank-specific wash factors for evaluating tank-by-tank processing. These wash data were then used collectively to evaluate some of the wash factors that are assumed for the overall SST waste inventory; specifically, wash factors for elements that would be found primarily in sludges. The final step in this study was to incorporate the characterization and wash factor data into a spreadsheet that provides insight into the effect of enhanced sludge washing on individual tank sludges as well as for groups of sludges that may be representative of different waste types. Spreadsheet results include the estimated mass and percentage of each element that would be removed with washing and leaching. Furthermore, estimated compositions are given of the final wash and leach streams and residual solids, in terms of both concentration and dry weight percent

GAS METHANE HYDRATES-RESEARCH STATUS, ANNOTATED BIBLIOGRAPHY, AND ENERGY IMPLICATIONS

Energy Technology Data Exchange (ETDEWEB)

James Sorensen; Jaroslav Solc; Bethany Bolles

2000-07-01

The objective of this task as originally conceived was to compile an assessment of methane hydrate deposits in Alaska from available sources and to make a very preliminary evaluation of the technical and economic feasibility of producing methane from these deposits for remote power generation. Gas hydrates have recently become a target of increased scientific investigation both from the standpoint of their resource potential to the natural gas and oil industries and of their positive and negative implications for the global environment After we performed an extensive literature review and consulted with representatives of the U.S. Geological Survey (USGS), Canadian Geological Survey, and several oil companies, it became evident that, at the current stage of gas hydrate research, the available information on methane hydrates in Alaska does not provide sufficient grounds for reaching conclusions concerning their use for energy production. Hence, the original goals of this task could not be met, and the focus was changed to the compilation and review of published documents to serve as a baseline for possible future research at the Energy & Environmental Research Center (EERC). An extensive annotated bibliography of gas hydrate publications has been completed. The EERC will reassess its future research opportunities on methane hydrates to determine where significant initial contributions could be made within the scope of limited available resources.

Water reduction in waste-activated sludge by resettling and filtration in batch. Phase (1): pilot-scale experiments to optimize performance.

Science.gov (United States)

Trapote, Arturo; Jover, Margarita; Cartagena, Pablo; El Kaddouri, Marouane; Prats, Daniel

2014-08-01

This article describes an effective procedure for reducing the water content of excess sludge production from a wastewater treatment plant by increasing its concentration and, as a consequence, minimizing the volume of sludge to be managed. It consists of a pre-dewatering sludge process, which is used as a preliminary step or alternative to the thickening. It is made up of two discontinuous sequential stages: the first is resettling and the second, filtration through a porous medium. The process is strictly physical, without any chemical additives or electromechanical equipment intervening. The experiment was carried out in a pilot-scale system, consisting of a column of sedimentation that incorporates a filter medium. Different sludge heights were tested over the filter to verify the influence ofhydrostatic pressure on the various final concentrations of each stage. The results show that the initial sludge concentration may increase by more than 570% by the end of the process with the final volume of sludge being reduced in similar proportions and hydrostatic pressure having a limited effect on this final concentration. Moreover, the value of the hydrostatic pressure at which critical specific cake resistance is reached is established.

Filterability of membrane bioreactor (MBR) sludge: impacts of polyelectrolytes and mixing with conventional activated sludge.

Science.gov (United States)

Yigit, Nevzat O; Civelekoglu, Gokhan; Cinar, Ozer; Kitis, Mehmet

2010-01-01

The main objective of this work was to investigate the filterability of MBR sludge and its mixture with conventional activated sludge (CAS). In addition, the impacts of type and dose of various polyelectrolytes, filter type and sludge properties on the filterability of both MBR and Mixed sludges were determined. Specific cake resistance (SCR) measured by the Buchner funnel filtration test apparatus and the solids content of the resulting sludge cake were used to assess the dewaterability of tested sludges. The type of filter paper used in Buchner tests affected the results of filterability for MBR, CAS and Mixed sludges. SCR values and optimum polyelectrolyte doses increased with increasing MLSS concentrations in the MBR, which suggested that increase in MLSS concentrations accompanied by increases in EPS and SMP concentrations and a shift toward smaller particles caused poorer dewaterability of the MBR sludge. The significant differences observed among the filterability of CAS and MBR sludges suggested that MLSS alone is not a good predictor of sludge dewaterability. Combining CAS and MBR sludges at different proportions generally improved their dewaterability. Combining MBR sludges having typically high MLSS and EPS concentrations with CAS having much lower MLSS concentrations may be an option for full-scale treatment plants experiencing sludge dewaterability problems. Better filterability and higher cake dry solids were achieved with cationic polyelectrolytes compared to anionic and non-ionic ones for all sludge types tested.

Experimental studies of relevance on zirconium nitrate raffinate sludge for its disposal as well as zirconium recovery

International Nuclear Information System (INIS)

Brahmananda Reddy, G.; Narasimha Murty, B.; Ravindra, H.R.

2013-01-01

One of the many routes of production of nuclear grade zirconium dioxide involve separation of zirconium and hafnium by solvent extraction of zirconium nitrate using tri-n-butyl phosphate followed by precipitation of zirconium with ammonia and finally calcination of the so obtained hydrated zirconia at elevated temperature. The zirconium feed solution as is generated from digestion of zirconium washed dried frit (produced by the caustic fusion of zircon sand which is one of the beach sand heavy minerals) in nitric acid contain considerable amount of sludge material and after solvent extraction this whole sludge material rests with raffinate. This sludge material has a scope to contain considerable amounts of zirconium along with other metal ions such as hafnium, aluminium, iron, etc. besides nitric acid and it constitutes one of the important solid wastes that needs to be disposed suitably. One of the disposal means of this sludge material is to use it as a land fill for which two important criteria are to be viz the pH of 10% solid waste solution should be near to neutral pH and the loss on ignition at 550℃ on dry basis of the sludge to be below 20%. In order to study the implications of presence of varying amounts of zirconium nitrate in the sludge on the pH of 10% solution of the sludge various synthetic zirconium nitrate solid waste were prepared using the sludge material generated at the laboratory during the analysis of zirconium washed dried frit. Presence of zirconium in the sludge is expected to decrease the overall pH of the 10% solution of the sludge because zirconium is prone to hydrolyze especially locally when zirconium ion comes into contact with water according to the chemical equation Zr 4+ H 2 O → ZrO 2+ + 2H + . From this equation, it is clear that for every one mole of zirconium ions two moles of hydrogen ions are produced. This is verified experimentally using the synthetically prepared sludge materials with varying amounts of zirconium

Enhancement the conditioning of waste activated sludge through a sequence of freeze/thaw-electro-Fenton process

Directory of Open Access Journals (Sweden)

Shahheidar Narjes

2018-03-01

Full Text Available Sludge conditioning is an important stage in sludge management. In the present study, a sequence of freeze/thaw-electro-Fenton process was designed and specific resistance filtration (SRF was monitored during sludge conditioning as an important factor in sludge dewaterability. Furthermore, protein and polysaccharide concentrations were measured during the experiments. Results showed that the lowest SRF value contributed to −10°C in freezing process which showed a reducing trend by decreasing solution pH. In addition, results revealed that solution pH less than 3 caused a significant improvement in sludge dewatering; so the lowest SRF has been registered at pH = 2. By increasing current intensity from 0.5 to 1A, SRF values were reduced and then followed by an enhancement with increasing current intensity to 3.2 A. The lowest SRF value (6.1 × 104 m/kg was obtained at H2O2 = 30 mg/L which was the best conditions for sludge dewatering.

Fibrillar structure and elasticity of hydrating collagen: a quantitative multiscale approach.

Science.gov (United States)

Morin, Claire; Hellmich, Christian; Henits, Peter

2013-01-21

It is well known that hydration of collagenous tissues leads to their swelling, as well as to softening of their elastic behavior. However, it is much less clear which microstructural and micromechanical "rules" are involved in this process. Here, we develop a theoretical approach cast in analytical mathematical formulations, which is experimentally validated by a wealth of independent tests on collagenous tissues, such as X-ray diffraction, vacuum drying, mass measurements, and Brillouin light scattering. The overall emerging picture is the following: air-drying leaves water only in the gap zones between the triple-helical collagen molecules; upon re-hydration, the extrafibrillar space is established at volumes directly proportional to the hydration-induced swelling of the (micro) fibrils, until the maximum equatorial distance between the long collagen molecules is reached. Thereafter, the volume of the fibrils stays constant, and only the extrafibrillar volume continues to grow. At all these hydration stages, the elastic behavior is governed by the same, hydration-invariant mechanical interaction pattern of only two, interpenetrating mechanical phases: transversely isotropic molecular collagen and isotropic water (or empty pores in the vacuum-dried case). Copyright © 2012 Elsevier Ltd. All rights reserved.

Critical operational parameters for zero sludge production in biological wastewater treatment processes combined with sludge disintegration.

Science.gov (United States)

Yoon, Seong-Hoon; Lee, Sangho

2005-09-01

Mathematical models were developed to elucidate the relationships among process control parameters and the effect of these parameters on the performance of anoxic/oxic biological wastewater processes combined with sludge disintegrators (A/O-SD). The model equations were also applied for analyses of activated sludge processes hybrid with sludge disintegrators (AS-SD). Solubilization ratio of sludge in the sludge disintegrator, alpha, hardly affected sludge reduction efficiencies if the biomass was completely destructed to smaller particulates. On the other hand, conversion efficiency of non-biodegradable particulates to biodegradable particulates, beta, significantly affected sludge reduction efficiencies because beta was directly related to the accumulation of non-biodegradable particulates in bioreactors. When 30% of sludge in the oxic tank was disintegrated everyday and beta was 0.5, sludge reduction was expected to be 78% and 69% for the A/O-SD and AS-SD processes, respectively. Under this condition, the sludge disintegration number (SDN), which is the amount of sludge disintegrated divided by the reduced sludge, was calculated to be around 4. Due to the sludge disintegration, live biomass concentration decreased while other non-biodegradable particulates concentration increased. As a consequence, the real F/M ratio was expected to be much higher than the apparent F/M. The effluent COD was maintained almost constant for the range of sludge disintegration rate considered in this study. Nitrogen removal efficiencies of the A/O-SD process was hardly affected by the sludge disintegration until daily sludge disintegration reaches 40% of sludge in the oxic tank. Above this level of sludge disintegration, autotrophic biomass concentration decreases overly and TKN in the effluent increases abruptly in both the A/O-SD and AS-SD processes. Overall, the trends of sludge reduction and effluent quality according to operation parameters matched well with experimental results

Effects of Sludge-amendment on Mineralization of Pyrene and Microorganisms in Sludge and Soil

DEFF Research Database (Denmark)

Klinge, C; Gejlsbjerg, B; Ekelund, Flemming

2001-01-01

. Sludge-amendment enhanced the mineralization of pyrene in the soil compared to soil without sludge, and the most extensive mineralization was observed when the sludge was kept in a lump. The number of protozoa, heterotrophic bacteria and pyrene-mineralizing bacteria was much higher in the sludge compared...... to the soil. The amendment of sludge did not affect the number of protozoa and bacteria in the surrounding soil, which indicated that organic contaminants in the sludge had a little effect on the number of protozoa and bacteria in the surrounding soil...

Numerical analysis of wellbore instability in gas hydrate formation during deep-water drilling

Science.gov (United States)

Zhang, Huaiwen; Cheng, Yuanfang; Li, Qingchao; Yan, Chuanliang; Han, Xiuting

2018-02-01

Gas hydrate formation may be encountered during deep-water drilling because of the large amount and wide distribution of gas hydrates under the shallow seabed of the South China Sea. Hydrates are extremely sensitive to temperature and pressure changes, and drilling through gas hydrate formation may cause dissociation of hydrates, accompanied by changes in wellbore temperatures, pore pressures, and stress states, thereby leading to wellbore plastic yield and wellbore instability. Considering the coupling effect of seepage of drilling fluid into gas hydrate formation, heat conduction between drilling fluid and formation, hydrate dissociation, and transformation of the formation framework, this study established a multi-field coupling mathematical model of the wellbore in the hydrate formation. Furthermore, the influences of drilling fluid temperatures, densities, and soaking time on the instability of hydrate formation were calculated and analyzed. Results show that the greater the temperature difference between the drilling fluid and hydrate formation is, the faster the hydrate dissociates, the wider the plastic dissociation range is, and the greater the failure width becomes. When the temperature difference is greater than 7°C, the maximum rate of plastic deformation around the wellbore is more than 10%, which is along the direction of the minimum horizontal in-situ stress and associated with instability and damage on the surrounding rock. The hydrate dissociation is insensitive to the variation of drilling fluid density, thereby implying that the change of the density of drilling fluids has a minimal effect on the hydrate dissociation. Drilling fluids that are absorbed into the hydrate formation result in fast dissociation at the initial stage. As time elapses, the hydrate dissociation slows down, but the risk of wellbore instability is aggravated due to the prolonged submersion in drilling fluids. For the sake of the stability of the wellbore in deep

Low-pressure hydraulic technique for slurrying radioactive sludges in waste tanks

International Nuclear Information System (INIS)

Bradley, R.F.; Parsons, F.A.; Goodlett, C.B.; Mobley, R.M.

1977-11-01

Present technology for the removal of sludges from radioactive liquid waste storage tanks at the Savannah River Plant (SRP) requires large volumes of fresh water added through high-pressure (approx.3000 psig) nozzles positioned to resuspend and slurry the sludge. To eliminate the cost of storing and evaporating these large volumes of water (several hundred thousand gallons per tank cleaned), a technique was developed at the Savannah River Laboratory (SRL) to use recirculating, radioactive, supernate solution to resuspend the sludge. The system consists in part of a single-stage centrifugal pump operating in the sludge at approx.100 psia. Recirculating supernate is drawn into the bottom of the pump and forced out through two oppositely directed nozzles to give liquid jets with a sludge-slurrying capability equal to that obtained with the present high-pressure system. In addition to eliminating the addition of large quantities of water to the tanks, the low-pressure recirculating technique requires only approximately one-sixth of the power required by the high-pressure system. Test results with clay (as a simulant for sludge) in a waste tank mockup confirmed theoretical predictions that jets with the same momentum gave essentially the same sludge-slurrying patterns. The effective cleaning radius of the recirculating jet was directly proportional to the product of the nozzle velocity and the nozzle diameter (U 0 D). At the maximum U 0 D developed by the pump (approx.14 ft 2 /s), the effective cleaning radius in the tank mockup was approx.20 feet

Intermittent Ozonation to Reduce Excess Biological Sludge in SBR

Directory of Open Access Journals (Sweden)

Afshin Takdastan

2009-09-01

Full Text Available A combination of ozonation and an aerobic biological process such as the activated sludge has been recently developed as an alternative solution for sludge reduction with the objective of minimizing the excess biological sludge production. In this study, two SBR reactors each with a capacity of 20 liters and controlled by an on-line system are used. Once the steady state conditions were set in the reactors, sampling and testing of such parameters as COD, MLSS, MLVSS, DO, SOUR, SVI, residual ozone, and Y coefficient were performed over the 8 months of research. Results showed that during the solid retention time of 10 days, the kinetic coefficients of Y and Kd were 0.58 mg biomass/mg COD and 0.058 1/day, respectively. In the next stage of the study, different concentrations of ozone in the reactor were intermittently used to reduce the excess biological sludge production. The results showed that 22 mg of ozone per 1 gram of MLSS in the reactor was able to reduce the yield coefficient Y from 0.58 to 0.23 mg Biomass/mg COD. In other words, the excess biological sludge reduced by 60% but the soluble COD increased slightly in the effluent and the removal percentage decreased from 92 in the blank reactor to 76 in the test reactor. While the amount of SVI and SOUR for this level of ozone concentration reached 6 mgO2/h.gVSS and 27 ml/g, respectively. No excess sludge was observed in the reactor for an ozone concentration of 27 mg per 1 gram of MLSS.

Effect of seed sludge on characteristics and microbial community of aerobic granular sludge.

Science.gov (United States)

Song, Zhiwei; Pan, Yuejun; Zhang, Kun; Ren, Nanqi; Wang, Aijie

2010-01-01

Aerobic granular sludge was cultivated by using different kinds of seed sludge in sequencing batch airlift reactor. The influence of seed sludge on physical and chemical properties of granular sludge was studied; the microbial community structure was probed by using scanning electron microscope and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that seed sludge played an important role on the formation of aerobic granules. Seed sludge taken from beer wastewater treatment plant (inoculum A) was more suitable for cultivating aerobic granules than that of sludge from municipal wastewater treatment plant (inoculum B). Cultivated with inoculum A, large amount of mature granules formed after 35 days operation, its SVI reached 32.75 mL/g, and SOUR of granular sludge was beyond 1.10 mg/(g x min). By contrast, it needed 56 days obtaining mature granules using inoculum B. DGGE profiles indicated that the dominant microbial species in mature granules were 18 and 11 OTU when inoculum A and B were respectively employed as seed sludge. The sequencing results suggested that dominant species in mature granules cultivated by inoculum A were Paracoccus sp., Devosia hwasunensi, Pseudoxanthomonas sp., while the dominant species were Lactococcus raffinolactis and Pseudomonas sp. in granules developed from inoculum B.

Enhancement of biogas production from sewage sludge by addition of grease trap sludge

International Nuclear Information System (INIS)

Grosser, A.; Neczaj, E.

2016-01-01

Highlights: • Addition of grease trap sludge is interesting option for sewage sludge digestion. • Co-digestion of grease trap sludge and sewage sludge improved efficiency of process. • The anaerobic digestion can be carried out at short hydraulic retention time. • Long chain fatty acids concentration was below the ranges for inhibition of anaerobic digestion. - Abstract: Despite having many benefits, a low degree of volatile solids removal as well as long retention time are the main factors limiting the performance of the anaerobic digestion. Co-digestion of sewage sludge with other organic waste (for example fat rich materials) is one of the few potential ways to enhance the performance of the anaerobic digestion. In this article, the effects of adding fatty rich materials on the performance and stability of semi-continuous anaerobic digestion of sewage sludge were investigated on a 6 l laboratory-scale reactor (working volume equal to 5.5 l). The reactor was operated in a semi-continuous mode with a hydraulic retention time of 10 days. The data presented in this paper relate to the period in which the grease trap sludge accounted for 10, 12, 14, 16 and 18% of the mixture on the volatile solids basis. The results clearly indicate that the addition of fat rich materials like grease trap sludge can lead to a satisfactory increase in biogas yield in digester treating sewage sludge. The results showed that co-digestion can enhance the biogas yield by 28–82% compared to anaerobic digestion of sewage sludge alone (control sample). Moreover, the addition of grease trap sludge to digesters resulted in increased volatile solids removal from 44.38% (control sample) to 57.77% (feedstock with 14% addition of grease trap sludge). It was found that the increase of grease trap sludge in the feedstock had a direct impact on the biogas production and methane yield. This proposal has also been confirmed by statistical analysis such as Pearson correlation coefficients and

Impact of sludge properties on solid-liquid separation of activated sludge

DEFF Research Database (Denmark)

Christensen, Morten Lykkegaard

2016-01-01

Solid-liquid separation of activated sludge is important both directly after the biological treatment of wastewater and for sludge dewatering. The separation of solid from the treated wastewater can be done by clarifiers (conventional plants) or membrane (MBR). Further, part of the sludge is taken...... out from the proces and usually dewatered before further handling. The separation process is costly. Moreover, the separation process depends on the composition and the properties of the sludge. The best separation is obtained for sludge that contains strong, compact flocs without single cells...... and dissolved extracellular polymeric substances (EPS). Polyvalent ions improve the floc strangth and improve the separation whereas monovalent ions (e.g. from road salt, sea water intrusion and industry) reduces impair the separation. Further high pH impairs the separation process due to floc disintegration...

Wasting Away: To Sludge or Not to Sludge?

Directory of Open Access Journals (Sweden)

L Nicolle

2001-01-01

Full Text Available Following a century of high standards of sanitation, food and water safety in North America are often taken for granted. Recent outbreaks of illness attributed to food and water contamination, however, have challenged this complacency. Now, sludge is added to the list of concerns. Sewage sludge is the muddy substance that remains after the treatment of municipal sewage. This material includes not only human waste, but also household and industrial toxic wastes disposed of in local sewers. Federal and provincial Canadian regulations support the use of this material as fertilizer, within acceptable guidelines, as does the Environmental Protection Agency in the United States. The safety of sludge, however, is questioned by some individuals and groups. Specifically, the risk of infectious agents and toxins to workers or other exposed individuals, and the potential for heavy metals and organic chemicals to be transferred from sludge-treated fields into crops are concerns.

Carbon-14 in sludge

International Nuclear Information System (INIS)

Fowler, J.R.; Coleman, C.J.

1983-01-01

The level of C-14 in high-level waste is needed to establish the amount of C-14 that will be released to the environment either as off-gas from the Defense Waste Processing Facility (DWPF) or as a component of saltstone. Available experimental data confirmed a low level of C-14 in soluble waste, but no data was available for sludge. Based on the processes used in each area, Purex LAW sludge in F-area and HM HAW sludge in H-area will contain the bulk of any sludge produced by the cladding. Accordingly, samples from Tank 8F containing Purex LAW and Tank 15H containing HM HAW were obtained and analyzed for C-14. These two waste types constitute approximately 70% of the total sludge inventory now stored in the waste tanks. Results from analyses of these two sludge types show: the total C-14 inventory in sludge now stored in the waste tanks is 6.8 Ci; C-14 releases to the atmosphere from the DWPF will average approximately 0.6 Ci annually at the projected sludge processing rate in the DWPF. 4 references, 2 tables

Direct measurement of methane hydrate composition along the hydrate equilibrium boundary

Science.gov (United States)

Circone, S.; Kirby, S.H.; Stern, L.A.

2005-01-01

The composition of methane hydrate, namely nW for CH 4??nWH2O, was directly measured along the hydrate equilibrium boundary under conditions of excess methane gas. Pressure and temperature conditions ranged from 1.9 to 9.7 MPa and 263 to 285 K. Within experimental error, there is no change in hydrate composition with increasing pressure along the equilibrium boundary, but nW may show a slight systematic decrease away from this boundary. A hydrate stoichiometry of n W = 5.81-6.10 H2O describes the entire range of measured values, with an average composition of CH4??5.99(??0.07) H2O along the equilibrium boundary. These results, consistent with previously measured values, are discussed with respect to the widely ranging values obtained by thermodynamic analysis. The relatively constant composition of methane hydrate over the geologically relevant pressure and temperature range investigated suggests that in situ methane hydrate compositions may be estimated with some confidence. ?? 2005 American Chemical Society.

Hydration and temperature in tennis - a practical review.

Science.gov (United States)

Kovacs, Mark S

2006-03-01

Competitive tennis is typically played in warm and hot environments. Because hypohydration will impair tennis performance and increases the risk of heat injury, consumption of appropriate fluid levels is necessary to prevent dehydration and enhance performance. The majority of research in this area has focused on continuous aerobic activity - unlike tennis, which has average points lasting less than ten seconds with rest periods dispersed between each work period. For this reason, hydration and temperature regulation methods need to be specific to the activity. Tennis players can sweat more than 2.5 L·h(-1) and replace fluids at a slower rate during matches than in practice. Latter stages of matches and tournaments are when tennis players are more susceptible to temperature and hydration related problems. Sodium (Na(+)) depletion, not potassium (K(+)), is a key electrolyte in tennis related muscle cramps. However, psychological and competitive factors also contribute. CHO drinks have been shown to promote fluid absorption to a greater degree than water alone, but no performance benefits have been shown in tennis players in short matches. It is advisable to consume a CHO beverage if practice or matches are scheduled longer than 90-120 minutes. Key PointsAlthough substantial research has been performed on temperature and hydration concerns in aerobic activities, there is little information with regard to tennis performance and safetyTennis athletes should be on an individualized hydration schedule, consuming greater than 200ml of fluid every changeover (approximately 15 minutes).Optimum hydration and temperature regulation will reduce the chance of tennis related muscle cramps and performance decrements.

In Situ Soft X-ray Spectromicroscopy of Early Tricalcium Silicate Hydration

Directory of Open Access Journals (Sweden)

Sungchul Bae

2016-12-01

Full Text Available The understanding and control of early hydration of tricalcium silicate (C3S is of great importance to cement science and concrete technology. However, traditional characterization methods are incapable of providing morphological and spectroscopic information about in situ hydration at the nanoscale. Using soft X-ray spectromicroscopy, we report the changes in morphology and molecular structure of C3S at an early stage of hydration. In situ C3S hydration in a wet cell, beginning with induction (~1 h and acceleration (~4 h periods of up to ~8 h, was studied and compared with ex situ measurements in the deceleration period after 15 h of curing. Analysis of the near-edge X-ray absorption fine structure showed that the Ca binding energy and energy splitting of C3S changed rapidly in the early age of hydration and exhibited values similar to calcium silicate hydrate (C–S–H. The formation of C–S–H nanoseeds in the C3S solution and the development of a fibrillar C–S–H morphology on the C3S surface were visualized. Following this, silicate polymerization accompanied by C–S–H precipitation produced chemical shifts in the peaks of the main Si K edge and in multiple scattering. However, the silicate polymerization process did not significantly affect the Ca binding energy of C–S–H.

Effects of sludge recirculation rate and mixing time on performance of a prototype single-stage anaerobic digester for conversion of food wastes to biogas and energy recovery.

Science.gov (United States)

Ratanatamskul, Chavalit; Saleart, Tawinan

2016-04-01

Food wastes have been recognized as the largest waste stream and accounts for 39.25 % of total municipal solid waste in Thailand. Chulalongkorn University has participated in the program of in situ energy recovery from food wastes under the Ministry of Energy (MOE), Thailand. This research aims to develop a prototype single-stage anaerobic digestion system for biogas production and energy recovery from food wastes inside Chulalongkorn University. Here, the effects of sludge recirculation rate and mixing time were investigated as the main key parameters for the system design and operation. From the results obtained in this study, it was found that the sludge recirculation rate of 100 % and the mixing time of 60 min per day were the most suitable design parameters to achieve high efficiencies in terms of chemical oxygen demand (COD), total solids (TS), and total volatile solid (TVS) removal and also biogas production by this prototype anaerobic digester. The obtained biogas production was found to be 0.71 m(3)/kg COD and the composition of methane was 61.6 %. Moreover, the efficiencies of COD removal were as high as 82.9 % and TVS removal could reach 83.9 % at the optimal condition. Therefore, the developed prototype single-stage anaerobic digester can be highly promising for university canteen application to recover energy from food wastes via biogas production.

Protists as bioindicators in activated sludge: Identification, ecology and future needs.

Science.gov (United States)

Foissner, Wilhelm

2016-08-01

When the activated sludge process was developed, operators and scientists soon recognized protists as valuable indicators. However, only when Curds et al. (1968) showed with a few photographs the need of ciliates for a clear plant effluent, sewage protistology began to bloom but was limited by the need of species identification. Still, this is a major problem although several good guides are available. Thus, molecular kits should be developed for identification. Protists are indicators in two stages of wastewater treatment, viz., in the activated sludge and in the environmental water receiving the plant effluent. Continuous control of the protist and bacterial communities can prevent biological sludge foaming and bulking and may greatly save money for sludge oxygenation because several protist species are excellent indicators for the amount of oxygen present. The investigation of the effluent-receiving rivers gives a solid indication about the long term function of sewage works. The literature on protist bioindication in activated sludge is widely distributed. Thus, I compiled the data in a simple Table, showing which communities and species indicate good, mediocre, or poor plant performance. Further, many details on indication are provided, such as sludge loading and nitrifying conditions. Such specific features should be improved by appropriate statistics and more reliable identification of species. Then, protistologists have a fair chance to become important in wastewater works. Activated sludge is a unique habitat for particular species, often poorly or even undescribed. As an example, I present two new species. The first is a minute (∼30μm) Metacystis that makes an up to 300μm-sized mucous envelope mimicking a sludge floc. The second is a Phialina that is unique in having the contractile vacuole slightly posterior to mid-body. Finally, I provide a list of species which have the type locality in sewage plants. Copyright © 2016 Elsevier GmbH. All rights

Gas hydrate in nature

Science.gov (United States)

Ruppel, Carolyn D.

2018-01-17

Gas hydrate is a naturally occurring, ice-like substance that forms when water and gas combine under high pressure and at moderate temperatures. Methane is the most common gas present in gas hydrate, although other gases may also be included in hydrate structures, particularly in areas close to conventional oil and gas reservoirs. Gas hydrate is widespread in ocean-bottom sediments at water depths greater than 300–500 meters (m; 984–1,640 feet [ft]) and is also present in areas with permanently frozen ground (permafrost). Several countries are evaluating gas hydrate as a possible energy resource in deepwater or permafrost settings. Gas hydrate is also under investigation to determine how environmental change may affect these deposits.

Introduction to the Gas Hydrate Master Project of Energy National Science and Technology Program of Taiwan

Science.gov (United States)

Yang, T. F.; Research Team of Gas Hydrate Project of CGS of Taiwan

2011-12-01

Bottom Simulating Reflectors (BSRs), which have been considered as one of major indicators of the gas hydrate in sub-seafloor, have been detected and widely distributed in offshore SW Taiwan. The Central Geological Survey of Taiwan launched a 4-year multidisciplinary gas hydrate investigation program in 2004 to explore the potential of gas hydrate resources in the area. The results indicate that enormous amounts of gas hydrate should occur beneath the seafloor, although none of solid gas hydrate samples have been found. Therefore, a second stage of another 4-year program started in 2008 to extend the studies/investigation. In the ongoing projects, some specific areas will be studied in detail to assess the components of gas hydrate petroleum system and provide a better assessment of the energy resource potential of gas hydrate in the target area. In addition to the field investigations, phase equilibrium of gas hydrate via experiment, theoretical modeling, and molecular simulations has also been studied. The results can provide insights into gas hydrate production technology. Considering the high potential energy resources, the committee of the energy national science and technology program suggests initiating a master project to plan the strategy and timeline for the gas hydrate exploration, exploitation and production in Taiwan. The plan will be introduced in this presentation.

Nuclear safety of extended sludge processing on tank 42 and 51 sludge (DWPF sludge feed batch one)

International Nuclear Information System (INIS)

Clemons, J.S.

1993-01-01

The sludge in tanks 42 and 51 is to be washed with inhibited water to remove soluble salts and combined in tank 51 in preparation for feed to DWPF. Since these tanks contain uranium and plutonium, the process of washing must be evaluated to ensure subcriticality is maintained. When the sludge is washed, inhibited water is added, the tank contents are slurried and allowed to settle. The sludge wash water is then decanted to the evaporator feed tank where it is fed to the evaporator to reduce the volume. The resulting evaporator concentrate is sent to a salt tank where it cools and forms crystallized salt cake. This salt cake will later be dissolved, processed in ITP and sent to Z-Area. This report evaluates the supernate and sludge during washing, the impact on the evaporator during concentration of decanted wash water, and the salt tank where the concentrated supernate is deposited. The conclusions generated in this report are specific to the sludge currently contained in tanks 42 and 51

[Skin hydration and hydrating products].

Science.gov (United States)

Duplan, H; Nocera, T

2018-05-01

One of the skin's principal functions is to protect the body against its environment by maintaining an effective epidermal barrier, not only against external factors, but also to prevent water loss from the body. Indeed, water homeostasis is vital for the normal physiological functioning of skin. Hydration levels affect not only visible microscopic parameters such as the suppleness and softness of skin, but also molecular parameters, enzyme activities and cellular signalling within the epidermis. The body is continually losing some of its water, but this phenomenon is limited and the optimal hydration gradient in skin is ensured via a set of sophisticated regulatory processes that rely on the functional and dynamic properties of the uppermost level of the skin consisting of the stratum corneum. The present article brings together data recently acquired in the fields of skin hydration and the characterisation of dehydrated or dry skin, whether through study of the regulatory processes involved or as a result of changes in the techniques used for in situ measurement, and thus in optimisation of management. Copyright © 2018. Published by Elsevier Masson SAS.

Portland cement hydration and early setting of cement stone intended for efficient paving materials

Science.gov (United States)

Grishina, A.

2017-10-01

Due to the growth of load on automotive roads, modern transportation engineering is in need of efficient paving materials. Runways and most advanced highways require Portland cement concretes. This makes important the studies directed to improvement of binders for such concretes. In the present work some peculiarities of the process of Portland cement hydration and early setting of cement stone with barium hydrosilicate sol were examined. It was found that the admixture of said sol leads to a shift in the induction period to later times without significant change in its duration. The admixture of a modifier with nanoscale barium hydrosilicates increases the degree of hydration of the cement clinker minerals and changes the phase composition of the hydration products; in particular, the content of portlandite and tricalcium silicate decreases, while the amount of ettringite increases. Changes in the hydration processes of Portland cement and early setting of cement stone that are caused by the nanoscale barium hydrosilicates, allow to forecast positive technological effects both at the stage of manufacturing and at the stage of operation. In particular, the formwork age can be reduced, turnover of molds can be increased, formation of secondary ettringite and corrosion of the first type can be eliminated.

Stability of sorbents based on hydrated TiO2 with different content of ZrO2

International Nuclear Information System (INIS)

Malykh, T.G.; Sharygin, L.M.

1983-01-01

The effect of ZrO 2 content in hydrated titanium dioxide on i s hydrothermat stabitity in the 120-350 deg C range, is investigated. It is shown that the specific surface of hydrated titanium dioxide in the process of hydrothermal treatment at different temperatures changes within a number of stages and depends on the zirconium dioxide contents in it. Sorbents are stable under hydrothermal conditions at temperatures not exceeding 300 deg C. The stabilizing effect of zirconiUm dioxide on the properties of hydrated titanium dioxide is most pronounced at 350 deg C

Hydration Properties of Ground Granulated Blast-Furnace Slag (GGBS Under Different Hydration Environments

Directory of Open Access Journals (Sweden)

Shuhua LIU

2017-02-01

Full Text Available The hydration properties of various cementitious materials containing Ground Granulated Blast-furnace Slag (GGBS, two alkali-activated slag cements (AAS-1 and AAS-2 in which sodium silicate and sodium hydroxide act as alkaline activators respectively, supersulfated cement (SSC and slag Portland cement(PSC, are compared with ordinary Portland cement (OPC to investigate the effect of activating environment on the hydration properties in this study by determining the compressive strength of the pastes, the hydration heat of binders within 96 hours, and the hydration products at age of 28 days. The results show that C-S-H gels are the main hydrated products for all cementitious systems containing GGBS. Ca(OH2 is the hydration products of OPC and PSC paste. However, ettringite and gypsum crystals instead of Ca(OH2 are detected in SSC paste. Additionally, tobermorite, a crystalline C-S-H, and calcite are hydrated products in AAS-1. Tobermorite, cowlesite and calcite are hydrated products of AAS-2 as well. Based on strength results, AAS-1 paste exhibits the highest compressive strength followed by POC, PSC, SSC in order at all testing ages and AAS-2 give the lowest compressive strength except for the early age at 3 days, which is higher than SSC but still lower than PSC. From hydration heat analysis, alkalinity in the reaction solution is a vital factor influencing the initial hydration rate and the initial hydration rate from higher to lower is AAS-2, AAS-1, OPC, PSC and SSC. Although AAS possesses a faster reaction rate in the initial hours, cumulative hydration heat of AAS is comparably lower than that of OPC, but higher than those of PSC and SSC in turn, which indicates that the hydration heat of clinkers is much higher than that of slag.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14934

Sludge busters

Energy Technology Data Exchange (ETDEWEB)

Pichon, Max

2010-07-15

Full text: A few years ago, For Earth developed low energy sub-surface aeration systems to increase the biological activity in the wastewater sludge ponds. Then came the idea to introduce probiotic bacteria to really ramp up the process, which promises massive time and cost savings in sludge management. Increasing the volumes of specific bacteria reactivates the sludge, accelerating biological nutrient removal in general and, by tailoring the bacteria, targeting specific organic waste types. The technology is already running at more than 30 councils across NSW and in some commercial settings, such as dairy farms. Shane McKibbin, GM of For Earth, said the 'Probiotic, Low Energy Aeration System' offers considerable upside. “The cost savings have been enormous with some councils, including the work done at Woolgoolga Water Reclamation Plant at Coffs Harbour,” he said. Sludge settling in wastewater treatment plant lagoons is typically pumped out, centrifuged to remove water and then landfilled. In Woolgoolga's case that process was costing Coffs Harbour Water $150 a cubic metre; McKibbin said they've slashed that to a measly $5 a cubic metre. An array of 'industrial air stones' is dropped 1m below the surface to create an oxygenated blanket across the surface, overcoming the tendency of sludge ponds to stagnate. The key though is floating probiotic dosing lines across the surface, which kick-starts the probiotics process. “Previously, some operators just wanted to throw it on with a bucket, so the bacteria would get thrown into one corner of the pond. But since we introduced the dosing system it has really improved the overall performance,” said McKibbin.The dosing pump system automatically applies the bacteria into the dosing line according to a specified program, ensuring the probiotics are spread out across the pond and across the week. “I would say it improves and accelerates the result by 30 per cent,” he adds. “The biggest problem was that

Sludge busters

International Nuclear Information System (INIS)

Pichon, Max

2010-01-01

Full text: A few years ago, For Earth developed low energy sub-surface aeration systems to increase the biological activity in the wastewater sludge ponds. Then came the idea to introduce probiotic bacteria to really ramp up the process, which promises massive time and cost savings in sludge management. Increasing the volumes of specific bacteria reactivates the sludge, accelerating biological nutrient removal in general and, by tailoring the bacteria, targeting specific organic waste types. The technology is already running at more than 30 councils across NSW and in some commercial settings, such as dairy farms. Shane McKibbin, GM of For Earth, said the 'Probiotic, Low Energy Aeration System' offers considerable upside. “The cost savings have been enormous with some councils, including the work done at Woolgoolga Water Reclamation Plant at Coffs Harbour,” he said. Sludge settling in wastewater treatment plant lagoons is typically pumped out, centrifuged to remove water and then landfilled. In Woolgoolga's case that process was costing Coffs Harbour Water $150 a cubic metre; McKibbin said they've slashed that to a measly $5 a cubic metre. An array of 'industrial air stones' is dropped 1m below the surface to create an oxygenated blanket across the surface, overcoming the tendency of sludge ponds to stagnate. The key though is floating probiotic dosing lines across the surface, which kick-starts the probiotics process. “Previously, some operators just wanted to throw it on with a bucket, so the bacteria would get thrown into one corner of the pond. But since we introduced the dosing system it has really improved the overall performance,” said McKibbin.The dosing pump system automatically applies the bacteria into the dosing line according to a specified program, ensuring the probiotics are spread out across the pond and across the week. “I would say it improves and accelerates the result by 30 per cent,” he adds. “The biggest problem was that

Effect of operation conditions on ammonia evolution in isothermal composting of sewage sludge

International Nuclear Information System (INIS)

Nishimura, Koichi; Watanabe, Hiromasa; Hashimoto, Shoji; Kawakami, Waichiro

1985-07-01

In the isothermal composting of sewage sludge, influences of operation conditions on NH 3 evolution were studied to obtain informations on the sludge deodorization during composting. The pattern of CO 2 evolution from the sludge was not affected by the aeration rate or the bulking agent. On the other hand, the pattern of NH 3 evolution was affected by the fermentation condition and the overall weight ratios of C in CO 2 to N in NH 3 , CO 2 -C/NH 3 -N in the total gas evolved varied with fermentation time. The ratios approached to almost constant values ranging from 5 to 7 in earlier stages at higher aeration rate or temperature. These facts mean that the change of NH 3 evolution pattern with fermentation conditions is due to NH 3 absorption by the sludge and the bulking agent, and actually, the NH 3 generation is a simultaneous process with CO 2 generation. Therefore, deodorization by composting can be completed at the end of fermentation. (author)

Sludge Stabilization Campaign blend plan

International Nuclear Information System (INIS)

De Vries, M.L.

1994-01-01

This sludge stabilization blend plan documents the material to be processed and the order of processing for the FY95 Sludge Stabilization Campaign. The primary mission of this process is to reduce the inventory of unstable plutonium bearing sludge. The source of the sludge is residual and glovebox floor sweepings from the production of material at the Plutonium Finishing Plant (PFP). The reactive sludge is currently being stored in various gloveboxes at PFP. There are two types of the plutonium bearing material that will be thermally stabilized in the muffle furnace: Plutonium Reclamation Facility (PRF) sludge and Remote Mechanical C (RMC) Line material

Sewage Sludge Disposal with Energy Recovery by Fluidized Bed Gasification and CHP-Units

Energy Technology Data Exchange (ETDEWEB)

Horst, J.; Gross, B.; Kimmerle, K. [Inst. fuer ZukunftsEnergieSysteme, Saarbruecken (Germany); Eder, C. [Christian Eder Technology e.K., Neunkirchen (Germany)

2006-07-15

Sewage sludge is a composition of by-products collected during the different stages of the waste water cleaning process of communal and industrial treatment plants. Because of its harmful impacts on environment as well as animals - and mankind - health sewage sludge has become a problem. Therefore disposal of sludge is today on a crossroad depending on the discussion about soil contamination by using the sludge as fertiliser. Some countries are now abandoning disposal to agriculture and are entering into thermal treatment with the argument: 'Harmful substances already separated with high financial effort should definitely be removed from the food cycle and should not return indirectly via the fields to food and water'. The SEDIS project - a project funded by the European Commission under the specific research and technological development programme 'Promotion of innovation and encouragement of SME participation' - is aimed at eliminating the rising disposal problem of sewage sludge by an energy-related use of the raw sludge directly on site of wastewater treatment plants. SEDIS is developing an innovative, self-sustaining system to process liquid and pasty waste such as sewage sludge and solid biomass to utilise product-gas for power-generation direct on site. This process is called ETVS-process and is patented by Christian Eder Technology e.K. Today, where each company has to look for sustainable savings, the SEDIS concept offers a decentralised process, self-sustaining from other energy sources and able to provide the whole treatment plant with energy. Furthermore the treatment plant would be independent of price policy of sludge disposers.

Hydration water and microstructure in calcium silicate and aluminate hydrates

International Nuclear Information System (INIS)

Fratini, Emiliano; Ridi, Francesca; Chen, Sow-Hsin; Baglioni, Piero

2006-01-01

Understanding the state of the hydration water and the microstructure development in a cement paste is likely to be the key for the improvement of its ultimate strength and durability. In order to distinguish and characterize the reacted and unreacted water, the single-particle dynamics of water molecules in hydrated calcium silicates (C 3 S, C 2 S) and aluminates (C 3 A, C 4 AF) were studied by quasi-elastic neutron scattering, QENS. The time evolution of the immobile fraction represents the hydration kinetics and the mobile fraction follows a non-Debye relaxation. Less sophisticated, but more accessible and cheaper techniques, like differential scanning calorimetry, DSC, and near-infrared spectroscopy, NIR, were validated through QENS results and they allow one to easily and quantitatively follow the cement hydration kinetics and can be widely applied on a laboratory scale to understand the effect of additives (i.e., superplasticizers, cellulosic derivatives, etc) on the thermodynamics of the hydration process. DSC provides information on the free water index and on the activation energy involved in the hydration process while the NIR band at 7000 cm -1 monitors, at a molecular level, the increase of the surface-interacting water. We report as an example the effect of two classes of additives widely used in the cement industry: superplasticizers, SPs, and cellulose derivatives. SPs interact at the solid surface, leading to a consistent increment of the activation energy for the processes of nucleation and growth of the hydrated phases. In contrast, the cellulosic additives do not affect the nucleation and growth activation energy, but cause a significant increment in the water availability: in other words the hydration process is more efficient without any modification of the solid/liquid interaction, as also evidenced by the 1 H-NMR. Additional information is obtained by scanning electron microscopy (SEM), ultra small angle neutron scattering (USANS) and wide

Novel understanding of calcium silicate hydrate from dilute hydration

KAUST Repository

Zhang, Lina; Yamauchi, Kazuo; Li, Zongjin; Zhang, Xixiang; Ma, Hongyan; Ge, Shenguang

2017-01-01

The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10

Gas composition of sludge residue profiles in a sludge treatment reed bed between loadings.

Science.gov (United States)

Larsen, Julie D; Nielsen, Steen M; Scheutz, Charlotte

2017-11-01

Treatment of sludge in sludge treatment reed bed systems includes dewatering and mineralization. The mineralization process, which is driven by microorganisms, produces different gas species as by-products. The pore space composition of the gas species provides useful information on the biological processes occurring in the sludge residue. In this study, we measured the change in composition of gas species in the pore space at different depth levels in vertical sludge residue profiles during a resting period of 32 days. The gas composition of the pore space in the sludge residue changed during the resting period. As the resting period proceeded, atmospheric air re-entered the pore space at all depth levels. The methane (CH 4 ) concentration was at its highest during the first part of the resting period, and then declined as the sludge residue became more dewatered and thereby aerated. In the pore space, the concentration of CH 4 often exceeded the concentration of carbon dioxide (CO 2 ). However, the total emission of CO 2 from the surface of the sludge residue exceeded the total emission of CH 4 , suggesting that CO 2 was mainly produced in the layer of newly applied sludge and/or that CO 2 was emitted from the sludge residue more readily compared to CH 4 .

Remediation of soils, sediments and sludges by extraction with organic solvents

NARCIS (Netherlands)

Noordkamp, E.R.

1999-01-01

Remediation of contaminated soils, sediments and sludges by extraction with organic solvents is still in the initial stages of development. So far hardly any scientific research has been carried out into this approach. Therefore, the main objective of the present investigation was to study

Sludge recovery apparatus

International Nuclear Information System (INIS)

Marmo, A.R.

1979-01-01

An improved design of a sludge recovery apparatus used in the fabrication of nuclear fuel is described. This apparatus provides for automatic separation of sludge from the grinder coolant, drying of the sludge into a flowable powder and transfer of the dry powder to a salvage container. It can be constructed to comply with criticality-safe-geometry requirements and to obviate need for operating personnel in its immediate vicinity. (UK)

Historical methane hydrate project review

Science.gov (United States)

Collett, Timothy; Bahk, Jang-Jun; Frye, Matt; Goldberg, Dave; Husebo, Jarle; Koh, Carolyn; Malone, Mitch; Shipp, Craig; Torres, Marta

2013-01-01

In 1995, U.S. Geological Survey made the first systematic assessment of the volume of natural gas stored in the hydrate accumulations of the United States. That study, along with numerous other studies, has shown that the amount of gas stored as methane hydrates in the world greatly exceeds the volume of known conventional gas resources. However, gas hydrates represent both a scientific and technical challenge and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of gas hydrates in nature, (2) assessing the volume of natural gas stored within various gas hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural gas hydrates, and (5) analyzing the effects of methane hydrate on drilling safety.Methane hydrates are naturally occurring crystalline substances composed of water and gas, in which a solid water-­‐lattice holds gas molecules in a cage-­‐like structure. The gas and water becomes a solid under specific temperature and pressure conditions within the Earth, called the hydrate stability zone. Other factors that control the presence of methane hydrate in nature include the source of the gas included within the hydrates, the physical and chemical controls on the migration of gas with a sedimentary basin containing methane hydrates, the availability of the water also included in the hydrate structure, and the presence of a suitable host sediment or “reservoir”. The geologic controls on the occurrence of gas hydrates have become collectively known as the “methane hydrate petroleum system”, which has become the focus of numerous hydrate research programs.Recognizing the importance of methane hydrate research and the need for a coordinated

On the rheological characteristics of sewage sludge

Directory of Open Access Journals (Sweden)

Tomáš Vítěz

2010-01-01

Full Text Available The work is focused on characterization of rheological behavior of sewage sludges sampled at different stages of waste water treatment. The main attention was focused on dynamic viscosity dependence on temperature, and shear rate. The sludge samples were examined under temperature ranging from 1 °C to 25 °C and under shear rate ranging from 0.34 s−1 to 68 s−1. Rotary digital viscometer (concentric cylinders geometry was used to perform the reological measurements. The solids content of the sludge samples ranged from 0.43 % to 21.45 % (A and C samples, respectively and ash free dry mass from 56.21 % to 67.80 % (A and B samples, respectively. The tested materials were found to be of non–Newtoninan nature and temperature dependent. Measured data were successfully cha­ra­cte­ri­zed by several mathematical models (Arrhenius, Bingham Plastic, Casson Law, Exponential, Gaussian, and IPC Paste in MATLAB® software with satisfying correlations between experimental and computed results. The best match (R2 = 0.999 was received with use of Gaussian model, in both cases, shear rate and temperature dependence. The results are quite useful e.g. for the purpose of technological equipment design.

Gas composition of sludge residue profiles in a sludge treatment reed bed between loadings

DEFF Research Database (Denmark)

Larsen, Julie Dam; Nielsen, Steen M; Scheutz, Charlotte

2017-01-01

Treatment of sludge in sludge treatment reed bed systems includes dewatering and mineralization. The mineralization process, which is driven by microorganisms, produces different gas species as by-products. The pore space composition of the gas species provides useful information on the biological...... processes occurring in the sludge residue. In this study, we measured the change in composition of gas species in the pore space at different depth levels in vertical sludge residue profiles during a resting period of 32 days. The gas composition of the pore space in the sludge residue changed during...

Hydraulic and Mechanical Effects from Gas Hydrate Conversion and Secondary Gas Hydrate Formation during Injection of CO2 into CH4-Hydrate-Bearing Sediments

Science.gov (United States)

Bigalke, N.; Deusner, C.; Kossel, E.; Schicks, J. M.; Spangenberg, E.; Priegnitz, M.; Heeschen, K. U.; Abendroth, S.; Thaler, J.; Haeckel, M.

2014-12-01

The injection of CO2 into CH4-hydrate-bearing sediments has the potential to drive natural gas production and simultaneously sequester CO2 by hydrate conversion. The process aims at maintaining the in situ hydrate saturation and structure and causing limited impact on soil hydraulic properties and geomechanical stability. However, to increase hydrate conversion yields and rates it must potentially be assisted by thermal stimulation or depressurization. Further, secondary formation of CO2-rich hydrates from pore water and injected CO2 enhances hydrate conversion and CH4 production yields [1]. Technical stimulation and secondary hydrate formation add significant complexity to the bulk conversion process resulting in spatial and temporal effects on hydraulic and geomechanical properties that cannot be predicted by current reservoir simulation codes. In a combined experimental and numerical approach, it is our objective to elucidate both hydraulic and mechanical effects of CO2 injection and CH4-CO2-hydrate conversion in CH4-hydrate bearing soils. For the experimental approach we used various high-pressure flow-through systems equipped with different online and in situ monitoring tools (e.g. Raman microscopy, MRI and ERT). One particular focus was the design of triaxial cell experimental systems, which enable us to study sample behavior even during large deformations and particle flow. We present results from various flow-through high-pressure experimental studies on different scales, which indicate that hydraulic and geomechanical properties of hydrate-bearing sediments are drastically altered during and after injection of CO2. We discuss the results in light of the competing processes of hydrate dissociation, hydrate conversion and secondary hydrate formation. Our results will also contribute to the understanding of effects of temperature and pressure changes leading to dissociation of gas hydrates in ocean and permafrost systems. [1] Deusner C, Bigalke N, Kossel E

Sludge technology assessment

International Nuclear Information System (INIS)

Krause, T.R.; Cunnane, J.C.; Helt, J.E.

1994-12-01

The retrieval, processing, and generation of final waste forms from radioactive tank waste sludges present some of the most challenging technical problems confronting scientists and engineers responsible for the waste management programs at the various Department of Energy laboratories and production facilities. Currently, the Department of Energy is developing a strategy to retrieve, process, and generate a final waste form for the sludge that meets the acceptance criteria for the final disposition. An integral part of this strategy will be use of separation processes that treat the sludge; the goal is to meet feed criteria for the various processes that will generate the final waste form, such as vitrification or grouting. This document is intended to (1) identify separation technologies which are being considered for sludge treatment at various DOE sites, (2) define the current state of sludge treatment technology, (3) identify what research and development is required, (4) identify current research programs within either DOE or academia developing sludge treatment technology, and (5) identify commercial separation technologies which may be applicable. Due to the limited scope of this document, technical evaluations regarding the need for a particular separations technology, the current state of development, or the research required for implementation, are not provided

Activated sludge model No. 3

DEFF Research Database (Denmark)

Gujer, W.; Henze, M.; Mino, T.

1999-01-01

The Activated Sludge Model No. 3 (ASM3) can predict oxygen consumption, sludge production, nitrification and denitrification of activated sludge systems. It relates to the Activated Sludge Model No. 1 (ASM1) and corrects for some defects of ASM I. In addition to ASM1, ASM3 includes storage of org...

Strength Estimation for Hydrate-Bearing Sediments From Direct Shear Tests of Hydrate-Bearing Sand and Silt

Science.gov (United States)

Liu, Zhichao; Dai, Sheng; Ning, Fulong; Peng, Li; Wei, Houzhen; Wei, Changfu

2018-01-01

Safe and economic methane gas production, as well as the replacement of methane while sequestering carbon in natural hydrate deposits, requires enhanced geomechanical understanding of the strength and volume responses of hydrate-bearing sediments during shear. This study employs a custom-made apparatus to investigate the mechanical and volumetric behaviors of carbon dioxide hydrate-bearing sediments subjected to direct shear. The results show that both peak and residual strengths increase with increased hydrate saturation and vertical stress. Hydrate contributes mainly the cohesion and dilatancy constraint to the peak strength of hydrate-bearing sediments. The postpeak strength reduction is more evident and brittle in specimens with higher hydrate saturation and under lower stress. Significant strength reduction after shear failure is expected in silty sediments with high hydrate saturation Sh ≥ 0.65. Hydrate contribution to the residual strength is mainly by increasing cohesion at low hydrate saturation and friction at high hydrate saturation. Stress state and hydrate saturation are dominating both the stiffness and the strength of hydrate-bearing sediments; thus, a wave velocity-based peak strength prediction model is proposed and validated, which allows for precise estimation of the shear strength of hydrate-bearing sediments through acoustic logging data. This method is advantageous to geomechanical simulators, particularly when the experimental strength data of natural samples are not available.

Gas hydrate concentration and characteristics within Hydrate Ridge inferred from multicomponent seismic reflection data

Science.gov (United States)

Kumar, Dhananjay; Sen, Mrinal K.; Bangs, Nathan L.

2007-12-01

A seismic experiment composed of streamer and ocean bottom seismometer (OBS) surveys was conducted in the summer of 2002 at southern Hydrate Ridge, offshore Oregon, to map the gas hydrate distribution within the hydrate stability zone. Gas hydrate concentrations within the reservoir can be estimated with P wave velocity (Vp); however, we can further constrain gas hydrate concentrations using S wave velocity (Vs), and use Vs through its relationship to Vp (Vp/Vs) to reveal additional details such as gas hydrate form within the matrix (i.e., hydrate cements the grains, becomes part of the matrix frame or floats in pore space). Both Vp and Vs can be derived simultaneously by inverting multicomponent seismic data. In this study, we use OBS data to estimate seismic velocities where both gas hydrate and free gas are present in the shallow sediments. Once Vp and Vs are estimated, they are simultaneously matched with modeled velocities to estimate the gas hydrate concentration. We model Vp using an equation based on a modification of Wood's equation that incorporates an appropriate rock physics model and Vs using an empirical relation. The gas hydrate concentration is estimated to be up to 7% of the rock volume, or 12% of the pore space. However, Vp and Vs do not always fit the model simultaneously. Vp can vary substantially more than Vs. Thus we conclude that a model, in which higher concentrations of hydrate do not affect shear stiffness, is more appropriate. Results suggest gas hydrates form within the pore space of the sediments and become part of the rock framework in our survey area.

Efficiency of a pilot-scale integrated sludge thickening and digestion reactor in treating low-organic excess sludge.

Science.gov (United States)

He, Qiang; Li, Jiang; Liu, Hongxia; Tang, Chuandong; de Koning, Jaap; Spanjers, Henri

2012-06-01

The sludge production from medium- and small-scale wastewater treatment plants in the Three Gorges Reservoir Region is low and non-stable; especially, the organic content in this sludge is low (near 40% of VS/TS). An integrated thickening and digestion (ISTD) reactor was developed to treat this low-organic excess sludge. After a flow test and start-up experiment of the reactor, a running experiment was used to investigate the excess sludge treatment efficiency under five different excess sludge inflows: 200, 300, 400, 500 and 400 L/d (a mixture of excess sludge and primary sludge in a volume ratio of 9:1). This trial was carried out in the wastewater treatment plant in Chongqing, which covers 80% of the Three Gorges Reservoir Region, under the following conditions: (1) sludge was heated to 38-40 degrees C using an electrical heater to maintain anaerobic mesophilic digestion; (2) the biogas produced was recirculated to mix raw sludge with anaerobic sludge in the reactor under the flow rate of 12.5 L/min. There were three main results. Firstly, the flow pattern of the inner reactor was almost completely mixed under the air flow of 12.0 L/min using clear water. Secondly, under all the different sludge inflows, the water content in the outlet sludge was below 93%. Thirdly, the organic content in the outlet sludge was decreased from 37% to 30% and from 24% to 20%, whose removal ratio was in relation to the organic content of the inlet sludge. The excess sludge treatment capacity of the ISTD reactor was according to the organic content in the excess sludge.

Sewage sludge disintegration - a review of current processes; Klaerschlammdesintegration - Ueberblick ueber verschiedene Verfahren

Energy Technology Data Exchange (ETDEWEB)

Nickel, K. [ULTRAWAVES Wasser- und Umwelttechnologien GmbH, Hamburg (Germany); Neis, U. [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Arbeitsbereich Abwasserwirtschaft

2003-07-01

Anaerobic stabilisation is an established technology for reducing sewage sludge volumes, but it has the drawback of low conversion rates. The speed of the process is determined by the hydrolysis of the solid fraction of the sludge. According to the current state of knowledge, exoenzymes produced by the fermenting microorganisms attack the particulate material and dissolve monomers. Production of exoenzymes is an energy-consuming process for the microorganisms; it reduces the energy gain and slows down cell growth. The same bacteria are responsible for aerobic and anaerobic hydrolysis. Therefore, the process of sludge destabilisation can be intensified considerably by making the whole organic fraction biologically available, i.e. by replacing the slow stage of enzymatic sludge hydrolysis by a chemical, thermal or mechanical stage. Sludge disintegration by one of these processes would intensify anaerobic degradation, reduce sludge volumes and enhance biogas production. (orig.) [German] Die anaerobe Stabilisierung ist anerkannte Regel der Technik und fuehrt zu einem teilweisen Abbau der organischen Bestandteile des Rohschlammes. Eine Verminderung der zu entsorgenden Schlammmasse geht damit einher. Wesentlicher Nachteil der anaeroben Klaerschlammstabilisierung ist die geringe Umsatzleistung dieses Prozesses. Dem Aufschluss der Feststoffe/grossen Molekuele des Schlammes kommt eine Schluesselrolle zu: die Hydrolyse der Rohschlammfeststoffe stellt den geschwindigkeitsbestimmenden Teilschritt des aneroben Abbauprozesses dar. Nach den gegenwaertigen Vorstellungen greifen von den fermentierenden Mikroorganismen produzierte Exoenzyme das partikulaere Material an und loesen Monomere heraus. Die Herstellung der Exoenzyme ist fuer die Mikroorganismen energetisch sehr aufwendig und vermindert den Energiegewinn und damit das Zellwachstum. Die Hydrolyse ist unabhaengig davon, ob sie aerob oder anaerob erfolgt, sie wird von denselben Bakterien bewerkstelligt. Man kann sich demnach

Bacterial composition of activated sludge - importance for floc and sludge properties

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Per H.; Thomsen, Trine R.; Nielsen, Jeppe L.

2003-07-01

Activated sludge flocs consist of numerous constituents which, together with other factors, are responsible for floc structure and floc properties. These properties largely determine the sludge properties such as flocculation, settling and dewaterability. In this paper we briefly review the present knowledge about the role of bacteria in relation to floc and sludge properties, and we present a new approach to investigate the identity and function of the bacteria in the activated sludge flocs. The approach includes identification of the important bacteria and a characterization of their physiological and functional properties. It is carried out by use of culture-independent molecular biological methods linked with other methods to study the physiology and function maintaining a single cell resolution. Using this approach it was found that floc-forming properties differed among the various bacterial groups, e.g. that different microcolony-forming bacteria had very different sensitivities to shear and that some of them deflocculated under anaerobic conditions. in our opinion, the approach to combine identity with functional analysis of the dominant bacteria in activated sludge by in situ methods is a very promising way to investigate correlations between presence of specific bacteria, and floc and sludge properties that are of interest. (author)

Radiation hygienization of raw sewage sludge

International Nuclear Information System (INIS)

Shah, M.R.; Lavale, D.S.; Rawat, P.; Benny, P.G.; Sharma, A.K.; Dey, G.R.; Bhave, V.

2001-01-01

'Radiation treatment of municipal sewage sludge can achieve resource conservation and recovery objectives. The liquid sludge irradiator of Sludge Hygienization Research Irradiator at Baroda (India) was operated for generating data on treatment of raw sludge containing 3-4 % solids. The plant system was modified for irradiating raw sludge without affecting basic irradiator initially designed to treat digested sludge. Hourly samples were analysed for estimation of disinfection dose requirement. Sand separated from the sludge was used as in-situ dosimeter by making use of its thermoluminescence property. Investigations are being carried out for regrowth of Total Coliforms in the sludge samples from this irradiator. Possibility of inadequate treatment due to geometric configuration of irradiator is being checked. (author)

Sewage sludges disinfection

International Nuclear Information System (INIS)

Alexandre, D.; Gevaudan, P.P.

1977-01-01

There is a hygienic risk in using biological sewage sludges for agriculture. Systematic analyses carried out on sludge samples obtained from purification plants in the Eastern and Southern part of France, show the almost uniform presence of pathogenic microorganisms. Some of them survive more than nine months after application to the soil. Conventional processes for disinfection, liming and heat, make the sludge unsuitable for agricultural use. On the other hand, irradiation involves no modification of structure and composition of sludges. Radiation doses required for disinfection vary according to the type of microorganism. Some of them are eliminated at rather low doses (200 krad), but mycobacteria, viruses and eggs of worms resist to more important doses. The security dose is estimated to be approx. 1000 krad

Degradation of slime extracellular polymeric substances and inhibited sludge flocs destruction contribute to sludge dewaterability enhancement during fungal treatment of sludge using filamentous fungus Mucor sp. GY-1.

Science.gov (United States)

Wang, Zhenyu; Zheng, Guanyu; Zhou, Lixiang

2015-09-01

Mechanisms responsible for the sludge dewaterability enhanced by filamentous fungi during fungal treatment of sludge were investigated in the present study. The filamentous fungus Mucor sp. GY-1, isolated from waste activated sludge, enhanced sludge dewaterability by 82.1% to achieve the lowest value of normalized sludge specific resistance to filtration (SRF), 8.18 × 10(10) m · L/kg · g-TSS. During the fungal treatment of sludge, 57.8% of slime extracellular polymeric substances (EPS) and 51.1% of polysaccharide in slime EPS were degraded, respectively, by Mucor sp. GY-1, contributing to the improvement of sludge dewaterability. Slime EPS is much more available for Mucor sp. GY-1 than either LB-EPS or TB-EPS that bound with microbial cells. In addition, filamentous fungus Mucor sp. GY-1 entrapped small sludge particles and inhibited the destruction of sludge flocs larger than 100 μm, thus enhancing sludge dewaterability, during fungal treatment of sludge using Mucor sp. GY-1. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of an efficient anaerobic co-digestion process for garbage, excreta, and septic tank sludge to create a resource recycling-oriented society.

Science.gov (United States)

Sun, Zhao-Yong; Liu, Kai; Tan, Li; Tang, Yue-Qin; Kida, Kenji

2017-03-01

In order to develop a resource recycling-oriented society, an efficient anaerobic co-digestion process for garbage, excreta and septic tank sludge was studied based on the quantity of each biomass waste type discharged in Ooki machi, Japan. The anaerobic digestion characteristics of garbage, excreta and 5-fold condensed septic tank sludge (hereafter called condensed sludge) were determined separately. In single-stage mesophilic digestion, the excreta with lower C/N ratios yielded lower biogas volumes and accumulated higher volumes of volatile fatty acid (VFA). On the other hand, garbage allowed for a significantly larger volatile total solid (VTS) digestion efficiency as well as biogas yield by thermophilic digestion. Thus, a two-stage anaerobic co-digestion process consisting of thermophilic liquefaction and mesophilic digestion phases was proposed. In the thermophilic liquefaction of mixed condensed sludge and household garbage (wet mass ratio of 2.2:1), a maximum VTS loading rate of 24g/L/d was achieved. In the mesophilic digestion of mixed liquefied material and excreta (wet mass ratio of 1:1), biogas yield reached approximately 570ml/g-VTS fed with a methane content of 55% at a VTS loading rate of 1.0g/L/d. The performance of the two-stage process was evaluated by comparing it with a single-stage process in which biomass wastes were treated separately. Biogas production by the two-stage process was found to increase by approximately 22.9%. These results demonstrate the effectiveness of a two-stage anaerobic co-digestion process in enhancement of biogas production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of empirical hydration distribution functions around polar atoms for assessing hydration structures of proteins

International Nuclear Information System (INIS)

Matsuoka, Daisuke; Nakasako, Masayoshi

2013-01-01

Highlights: ► Empirical distribution functions of water molecules in protein hydration are made. ► The functions measure how hydrogen-bond geometry in hydration deviate from ideal. ► The functions assess experimentally identified hydration structures of protein. - Abstract: To quantitatively characterize hydrogen-bond geometry in local hydration structures of proteins, we constructed a set of empirical hydration distribution functions (EHDFs) around polar protein atoms in the main and side chains of 11 types of hydrophilic amino acids (D. Matsuoka, M. Nakasako, Journal of Physical Chemistry B 113 (2009) 11274). The functions are the ensemble average of possible hydration patterns around the polar atoms, and describe the anisotropic deviations from ideal hydrogen bond geometry. In addition, we defined probability distribution function of hydration water molecules (PDFH) over the hydrophilic surface of a protein as the sum of EHDFs of solvent accessible polar protein atoms. The functions envelop most of hydration sites identified in crystal structures of proteins (D. Matsuoka, M. Nakasako, Journal of Physical Chemistry B 114 (2010) 4652). Here we propose the application of EHDFs and PDFHs for assessing crystallographically identified hydration structures of proteins. First, hydration water molecules are classified with respect to the geometry in hydrogen bonds in referring EHDFs. Difference Fourier electron density map weighted by PDFH of protein is proposed to identify easily density peaks as candidates of hydration water molecules. A computer program implementing those ideas was developed and used for assessing hydration structures of proteins

Improvement of sludge dewaterability and removal of sludge-borne metals by bioleaching at optimum pH.

Science.gov (United States)

Liu, Fenwu; Zhou, Lixiang; Zhou, Jun; Song, Xingwei; Wang, Dianzhan

2012-06-30

Bio-acidification caused by bio-oxidation of energy substances during bioleaching is widely known to play an important role in improving sludge-borne metals removal. Here we report that bioleaching also drastically enhances sludge dewaterability in a suitable pH level. To obtain the optimum initial concentrations of energy substances and pH values for sludge dewaterability during bioleaching, bio-oxidation of Fe(2+) and S(0) under co-inoculation with Acidithiobacillus thiooxidans TS6 and Acidothiobacillus ferrooxidans LX5 and their effects on sludge dewaterability and metals removal during sludge bioleaching were investigated. Results indicated that the dosage of energy substances with 2g/L S(0) and 2g/L Fe(2+) could obtain bio-oxidation efficiencies of up to 100% for Fe(2+) and 50% for S(0) and were the optimal dosages for sludge bioleaching. The removal efficiencies of sludge-borne Cu and Cr could reach above 85% and 40%, respectively, and capillary suction time (CST) of bioleached sludge decreased to as low as ∼10s from initial 48.9s for fresh sludge when sludge pH declined to ∼2.4 through bioleaching. These results confirm the potential of bioleaching as a novel method for improving sludge dewaterability as well as removal of metals. Copyright © 2012 Elsevier B.V. All rights reserved.

A Study on the quantification of hydration and the strength development mechanism of cementitious materials including amorphous phases by using XRD/Rietveld method

International Nuclear Information System (INIS)

Yamada, Kazuo; Hoshino, Seiichi; Hirao, Hiroshi; Yamashita, Hiroki

2008-01-01

X-ray diffraction (XRD)/Rietveld method was applied to measure the phase composition of cement. The quantative analysis concerning the progress of hydration was accomplished in an error of about the maximum 2-3% in spite of including amorphous materials such as blast furnace slag, fly ash, silica fume and C-S-H. The influence of the compressive strength on the lime stone fine powder mixture material was studied from the hydration analysis by Rietveld method. The two stages were observed in the strength development mechanism of cement; the hydration promotion of C 3 S in the early stage and the filling of cavities by carbonate hydrate for the longer term. It is useful to use various mixture materials for the formation of the resource recycling society and the durability improvement of concrete. (author)

In Situ Raman Analyses of Natural Gas and Gas Hydrates at Hydrate Ridge, Oregon

Science.gov (United States)

Peltzer, E. T.; White, S. N.; Dunk, R. M.; Brewer, P. G.; Sherman, A. D.; Schmidt, K.; Hester, K. C.; Sloan, E. D.

2004-12-01

During a July 2004 cruise to Hydrate Ridge, Oregon, MBARI's sea-going laser Raman spectrometer was used to obtain in situ Raman spectra of natural gas hydrates and natural gas venting from the seafloor. This was the first in situ analysis of gas hydrates on the seafloor. The hydrate spectra were compared to laboratory analyses performed at the Center for Hydrate Research, Colorado School of Mines. The natural gas spectra were compared to MBARI gas chromatography (GC) analyses of gas samples collected at the same site. DORISS (Deep Ocean Raman In Situ Spectrometer) is a laboratory model laser Raman spectrometer from Kaiser Optical Systems, Inc modified at MBARI for deployment in the deep ocean. It has been successfully deployed to depths as great as 3600 m. Different sampling optics provide flexibility in adapting the instrument to a particular target of interest. An immersion optic was used to analyze natural gas venting from the seafloor at South Hydrate Ridge ( ˜780 m depth). An open-bottomed cube was placed over the vent to collect the gas. The immersion optic penetrated the side of the cube as did a small heater used to dissociate any hydrate formed during sample collection. To analyze solid hydrates at both South and North Hydrate Ridge ( ˜590 m depth), chunks of hydrate were excavated from the seafloor and collected in a glass cylinder with a mesh top. A stand-off optic was used to analyze the hydrate inside the cylinder. Due to the partial opacity of the hydrate and the small focal volume of the sampling optic, a precision underwater positioner (PUP) was used to focus the laser spot onto the hydrate. PUP is a stand-alone system with three degrees-of-freedom, capable of moving the DORISS probe head with a precision of 0.1 mm. In situ Raman analyses of the gas indicate that it is primarily methane. This is verified by GC analyses of samples collected from the same site. Other minor constituents (such as CO2 and higher hydrocarbons) are present but may be in

Nitrite reduction and methanogenesis in a single-stage UASB reactor.

Science.gov (United States)

Borges, L I; López-Vazquez, C M; García, H; van Lier, J B

2015-01-01

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO(2)(-)-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO(2)(-)-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO(2)(-)-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO(2)(-) reduction to N₂. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

Ductile flow of methane hydrate

Science.gov (United States)

Durham, W.B.; Stern, L.A.; Kirby, S.H.

2003-01-01

Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

Cost and effectiveness comparisons of various types of sludge irradiation and sludge pasteurization treatments

International Nuclear Information System (INIS)

Morris, M.E.

1976-01-01

The radiation from 137 Cs, a major constituent of nuclear fuel reprocessing waste, can be used to sterilize sewage sludge. This paper compares the effectiveness and cost of heat pasteurization, irradiation, and thermoradiation (simultaneous heating/irradiation), three competing methods of sludge disinfection. The cost of irradiation and thermoradiation is slightly higher than heat pasteurization costs for liquid sludges, although minor changes in oil availability or prices could change this. If the viral destruction could be done easily by other means, a 500-kilorad irradiation dose would be effective and less costly. For dry sewage sludges, irradiation is as effective and much less costly than any of the liquid sludge disinfection processes. Irradiation of compost appears to be cheaper and more practical than any heat pasteurization process for the dry sludge (the insulating property of the compost makes heating difficult). 6 tables, 2 fig

F-Canyon Sludge Physical Properties

International Nuclear Information System (INIS)

Poirier, M. R.; Hansen, P. R.; Fink, S. D.

2005-01-01

The Site Deactivation and Decommissioning (SDD) Organization is evaluating options to disposition the 800 underground tanks (including removal of the sludge heels from these tanks). To support this effort, DandD requested assistance from Savannah River National Laboratory (SRNL) personnel to determine the pertinent physical properties to effectively mobilize the sludge from these tanks (Tanks 804, 808, and 809). SDD provided SRNL with samples of the sludge from Tanks 804, 808, and 809. The authors measured the following physical properties for each tank: particle settling rate, shear strength (i.e., settled solids yield stress), slurry rheology (i.e., yield stress and consistency), total solids concentration in the sludge, soluble solids concentration of the sludge, sludge density, and particle size distribution

Colloidal agglomerates in tank sludge: Impact on waste processing

International Nuclear Information System (INIS)

Bunker, B.C.; Martin, J.E.

1998-01-01

of agglomeration phenomena. This project summarizes work performed after almost two years of a three year project. Significant findings include: Particles in Actual Tank Wastes - Transmission electron microscopy of actual wastes shows that most sludges consist of agglomerates of submicron (< 10 -6 m) primary particles of hydrated oxides and insoluble salts. Model colloid suspensions for this work were selected to duplicate the compositions and particle morphologies in actual waste. Agglomeration of Primary Particles - Static light scattering measurements on both model suspensions and actual wastes show that in the basic salt solutions found in most tank wastes, primary particles undergo extensive aggregation to form fractal agglomerates. The fractal nature of the agglomerates has an enormous impact on slurry properties because fractal objects occupy much more space than dense objects at the same solids loading.'

Hydration rate of obsidian.

Science.gov (United States)

Friedman, I; Long, W

1976-01-30

The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years.

SLUDGE TREATMENT PROJECT PHASE 1 SLUDGE STORAGE OPTIONS. ASSESSMENT OF T PLANT VERSUS ALTERNATE STORAGE FACILITY

International Nuclear Information System (INIS)

Rutherford, W.W.; Geuther, W.J.; Strankman, M.R.; Conrad, E.A.; Rhoadarmer, D.D.; Black, D.M.; Pottmeyer, J.A.

2009-01-01

The CH2M HILL Plateau Remediation Company (CHPRC) has recommended to the U.S. Department of Energy (DOE) a two phase approach for removal and storage (Phase 1) and treatment and packaging for offsite shipment (Phase 2) of the sludge currently stored within the 105-K West Basin. This two phased strategy enables early removal of sludge from the 105-K West Basin by 2015, allowing remediation of historical unplanned releases of waste and closure of the 100-K Area. In Phase 1, the sludge currently stored in the Engineered Containers and Settler Tanks within the 105-K West Basin will be transferred into sludge transport and storage containers (STSCs). The STSCs will be transported to an interim storage facility. In Phase 2, sludge will be processed (treated) to meet shipping and disposal requirements and the sludge will be packaged for final disposal at a geologic repository. The purpose of this study is to evaluate two alternatives for interim Phase 1 storage of K Basin sludge. The cost, schedule, and risks for sludge storage at a newly-constructed Alternate Storage Facility (ASF) are compared to those at T Plant, which has been used previously for sludge storage. Based on the results of the assessment, T Plant is recommended for Phase 1 interim storage of sludge. Key elements that support this recommendation are the following: (1) T Plant has a proven process for storing sludge; (2) T Plant storage can be implemented at a lower incremental cost than the ASF; and (3) T Plant storage has a more favorable schedule profile, which provides more float, than the ASF. Underpinning the recommendation of T Plant for sludge storage is the assumption that T Plant has a durable, extended mission independent of the K Basin sludge interim storage mission. If this assumption cannot be validated and the operating costs of T Plant are borne by the Sludge Treatment Project, the conclusions and recommendations of this study would change. The following decision-making strategy, which is

SLUDGE TREATMENT PROJECT PHASE 1 SLUDGE STORAGE OPTIONS ASSESSMENT OF T PLANT VERSUS ALTERNATE STORAGE FACILITY

Energy Technology Data Exchange (ETDEWEB)

RUTHERFORD WW; GEUTHER WJ; STRANKMAN MR; CONRAD EA; RHOADARMER DD; BLACK DM; POTTMEYER JA

2009-04-29

The CH2M HILL Plateau Remediation Company (CHPRC) has recommended to the U.S. Department of Energy (DOE) a two phase approach for removal and storage (Phase 1) and treatment and packaging for offsite shipment (Phase 2) of the sludge currently stored within the 105-K West Basin. This two phased strategy enables early removal of sludge from the 105-K West Basin by 2015, allowing remediation of historical unplanned releases of waste and closure of the 100-K Area. In Phase 1, the sludge currently stored in the Engineered Containers and Settler Tanks within the 105-K West Basin will be transferred into sludge transport and storage containers (STSCs). The STSCs will be transported to an interim storage facility. In Phase 2, sludge will be processed (treated) to meet shipping and disposal requirements and the sludge will be packaged for final disposal at a geologic repository. The purpose of this study is to evaluate two alternatives for interim Phase 1 storage of K Basin sludge. The cost, schedule, and risks for sludge storage at a newly-constructed Alternate Storage Facility (ASF) are compared to those at T Plant, which has been used previously for sludge storage. Based on the results of the assessment, T Plant is recommended for Phase 1 interim storage of sludge. Key elements that support this recommendation are the following: (1) T Plant has a proven process for storing sludge; (2) T Plant storage can be implemented at a lower incremental cost than the ASF; and (3) T Plant storage has a more favorable schedule profile, which provides more float, than the ASF. Underpinning the recommendation of T Plant for sludge storage is the assumption that T Plant has a durable, extended mission independent of the K Basin sludge interim storage mission. If this assumption cannot be validated and the operating costs of T Plant are borne by the Sludge Treatment Project, the conclusions and recommendations of this study would change. The following decision-making strategy, which is

Fate of return activated sludge after ozonation: an optimization study for sludge disintegration.

Science.gov (United States)

Demir, Ozlem; Filibeli, Ayse

2012-09-01

The effects of ozonation on sludge disintegration should be investigated before the application of ozone during biological treatment, in order to minimize excess sludge production. In this study, changes in sludge and supernatant after ozonation of return activated sludge were investigated for seven different ozone doses. The optimum ozone dose to avoid inhibition of ozonation and high ozone cost was determined in terms of disintegration degree as 0.05 g O3/gTS. Suspended solid and volatile suspended solid concentrations of sludge decreased by 77.8% and 71.6%, respectively, at the optimum ozone dose. Ozonation significantly decomposed sludge flocs. The release of cell contents was proved by the increase of supernatant total nitrogen (TN) and phosphorus (TP). While TN increased from 7 mg/L to 151 mg/L, TP increased from 8.8 to 33 mg/L at the optimum ozone dose. The dewaterability and filterability characteristics of the ozonated sludge were also examined. Capillary suction time increased with increasing ozone dosage, but specific resistance to filtration increased to a specific value and then decreased dramatically. The particle size distribution changed significantly as a result of floc disruption at an optimum dose of 0.05 gO3/gTS.

Valorization of pellets from municipal WWTP sludge in lightweight clay ceramics

International Nuclear Information System (INIS)

Cusido, Joan A.; Soriano, Cecilia

2011-01-01

A direct result of the growing number of municipal wastewater-treatment plants (WWTPs) has been an increase in the generation of large amounts of sewage sludge that requires environmentally acceptable final destination. To decrease the volume of sludge, a common technique is drying the sludge at a low temperature in rotary kilns. The result of this process is a granulated material consisting of dehydrated sludge pellets. After this treatment, this pelletized material becomes easier to manipulate, but it also becomes a more toxic waste, containing dangerous substances, mostly of the lipid type. At its final stage, this material is usually incinerated, used as a comburent material, used as an agricultural fertilizer, or used in the cement industry. Each application has its own problems and requires remediation measures from the safety and environmental viewpoints. In this study, we looked beyond these possible applications and analyzed the transformation of sewage sludge through a ceramization process into a material similar to expanded clays; we subsequently explored its uses in the building industry or in the agriculture industry, among others. Both the properties of the product material and the production method were characterized, and an environmental analysis was conducted. The new, lightweight material had a microstructure with open porosity and low thermal conductivity. Environmental characterization such as the leaching test revealed that undetectable amounts of hazardous metals from the sludge were present in the leachate after the sludge went through a thermal treatment, despite their initial presence (with the exception of vanadium, which could pose some restrictions on some of the proposed uses for the final product). Toxicity tests also showed negative results. The study of gaseous emissions during production revealed emissions factors similar to those during the production of conventional clay ceramics, although with higher organic emissions. As for

Effects of substituting D2O for H2O on SANS measurements of hydrating cement

International Nuclear Information System (INIS)

Sabine, T.M.; Prior, M.J.

2002-01-01

Full text: Small angle neutron scattering (SANS) measurements of cement have been found useful in the investigation of the shape and growth of particles formed during hydration. Calorimetric measurements of hydrating cement samples have shown that the substitution of D 2 O for H 2 O has the effect of slowing the hydration process. In order to throw some light on this phenomenon, we have measured SANS profiles from cement samples hydrating in H 2 O and D 2 O. This involved obtaining SANS profiles at half-hourly intervals during the initial stage of hydration. The only instruments capable of this at present are located at the Hahn-Meitner Institute in Berlin and at the Nuclear Physics Institute at Rez near Prague. Initial experiments carried out on the V12a UltraSANS diffractometer at The Hahn-Meitner Institute were only partially successful owing to excessive multiple scattering in the D 2 O samples. Subsequent measurements were therefore carried out on the similar instrument at Rez near Prague which operates at a shorter neutron wavelength. Results from these measurements show profound differences in the evolution of cements hydrating in D 2 O and those hydrating in H 2 O

Face Masks for Noninvasive Ventilation: Fit, Excess Skin Hydration, and Pressure Ulcers.

Science.gov (United States)

Visscher, Marty O; White, Cynthia C; Jones, Jennifer M; Cahill, Thomas; Jones, Donna C; Pan, Brian S

2015-11-01

Pressure ulcers (stages III and IV) are serious safety events (ie, never events). Healthcare institutions are no longer reimbursed for costs to care for affected patients. Medical devices are the leading cause of pediatric pressure ulcers. Face masks for noninvasive ventilation were associated with a high percentage of pressure ulcers at our institution. A prospective cohort study investigated factors contributing to pressure ulcer development in 50 subjects using face masks for noninvasive ventilation. Color imaging, 3-dimensional surface imaging, and skin hydration measurements were used to identify early skin compromise and evaluate 3 interventions to reduce trauma: (1) a silicone foam dressing, (2) a water/polyethylene oxide hydrogel dressing, and (3) a flexible cloth mask. A novel mask fit technique was used to examine the impact of fit on the potential for skin compromise. Fifty subjects age 10.4 ± 9.1 y participated with color images for 22, hydration for 34, and mask fit analysis for 16. Of these, 69% had diagnoses associated with craniofacial anomalies. Stage I pressure ulcers were the most common injury. Skin hydration difference was 317 ± 29 for sites with erythema versus 75 ± 28 for sites without erythema (P skin erythema and pressure ulcers. This fit method is currently being utilized to select best-fit masks from available options, to identify the potential areas of increased tissue pressure, and to prevent skin injuries and their complications. Improvement of mask fit is an important priority for improving respiratory outcomes. Strategies to maintain normal skin hydration are important for protecting tissue integrity. Copyright © 2015 by Daedalus Enterprises.

Permeability of sediment cores from methane hydrate deposit in the Eastern Nankai Trough, Japan

Science.gov (United States)

Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Nagao, J.

2013-12-01

Effective and absolute permeability are key parameters for gas production from methane-hydrate-bearing sandy sediments. Effective and/or absolute permeability have been measured using methane-hydrate-bearing sandy cores and clayey and silty cores recovered from Daini Atsumi Knoll in the Eastern Nankai Trough during the 2012 JOGMEC/JAPEX Pressure coring operation. Liquid-nitrogen-immersed cores were prepared by rapid depressurization of pressure cores recovered by a pressure coring system referred to as the Hybrid PCS. Cores were shaped cylindrically on a lathe with spraying of liquid nitrogen to prevent hydrate dissociation. Permeability was measured by a flooding test or a pressure relaxation method under near in-situ pressure and temperature conditions. Measured effective permeability of hydrate-bearing sediments is less than tens of md, which are order of magnitude less than absolute permeability. Absolute permeability of clayey cores is approximately tens of μd, which would perform a sealing function as cap rocks. Permeability reduction due to a swelling effect was observed for a silty core during flooding test of pure water mimicking hydrate-dissociation-water. Swelling effect may cause production formation damage especially at a later stage of gas production from methane hydrate deposits. This study was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) that carries out Japan's Methane Hydrate R&D Program conducted by the Ministry of Economy, Trade and Industry (METI).

Lipid profiling in sewage sludge.

Science.gov (United States)

Zhu, Fenfen; Wu, Xuemin; Zhao, Luyao; Liu, Xiaohui; Qi, Juanjuan; Wang, Xueying; Wang, Jiawei

2017-06-01

High value-added reutilization of sewage sludge from wastewater treatment plants (WWTPs) is essential in sustainable development in WWTPs. However, despite the advantage of high value reutilization, this process must be based on a detailed study of organics in sludge. We used the methods employed in life sciences to determine the profile of lipids (cellular lipids, free fatty acids (FFAs), and wax/gum) in five sludge samples obtained from three typical WWTPs in Beijing; these samples include one sludge sample from a primary sedimentation tank, two activated sludge samples from two Anaerobic-Anoxic-Oxic (A2/O) tanks, and two activated sludge samples from two membrane bioreactor tanks. The percentage of total raw lipids varied from 2.90% to 12.3%. Sludge from the primary sedimentation tank showed the highest concentrations of lipid, FFA, and wax/gum and the second highest concentration of cellular lipids. All activated sludge contained an abundance of cellular lipids (>54%). Cells in sludge can from plants, animals, microbes and so on in wastewater. Approximately 14 species of cellular lipids were identified, including considerable high value-potential ceramide (9567-38774 mg/kg), coenzyme (937-3897 mg/kg), and some phosphatidylcholine (75-548 mg/kg). The presence of those lipid constituents would thus require a wider range of recovery methods for sludge. Both cellular lipids and FFAs contain an abundance of C16-C18 lipids at high saturation level, and they serve as good resources for biodiesel production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Overview: Nucleation of clathrate hydrates.

Science.gov (United States)

Warrier, Pramod; Khan, M Naveed; Srivastava, Vishal; Maupin, C Mark; Koh, Carolyn A

2016-12-07

Molecular level knowledge of nucleation and growth of clathrate hydrates is of importance for advancing fundamental understanding on the nature of water and hydrophobic hydrate formers, and their interactions that result in the formation of ice-like solids at temperatures higher than the ice-point. The stochastic nature and the inability to probe the small length and time scales associated with the nucleation process make it very difficult to experimentally determine the molecular level changes that lead to the nucleation event. Conversely, for this reason, there have been increasing efforts to obtain this information using molecular simulations. Accurate knowledge of how and when hydrate structures nucleate will be tremendously beneficial for the development of sustainable hydrate management strategies in oil and gas flowlines, as well as for their application in energy storage and recovery, gas separation, carbon sequestration, seawater desalination, and refrigeration. This article reviews various aspects of hydrate nucleation. First, properties of supercooled water and ice nucleation are reviewed briefly due to their apparent similarity to hydrates. Hydrate nucleation is then reviewed starting from macroscopic observations as obtained from experiments in laboratories and operations in industries, followed by various hydrate nucleation hypotheses and hydrate nucleation driving force calculations based on the classical nucleation theory. Finally, molecular simulations on hydrate nucleation are discussed in detail followed by potential future research directions.

Overview: Nucleation of clathrate hydrates

Science.gov (United States)

Warrier, Pramod; Khan, M. Naveed; Srivastava, Vishal; Maupin, C. Mark; Koh, Carolyn A.

2016-12-01

Molecular level knowledge of nucleation and growth of clathrate hydrates is of importance for advancing fundamental understanding on the nature of water and hydrophobic hydrate formers, and their interactions that result in the formation of ice-like solids at temperatures higher than the ice-point. The stochastic nature and the inability to probe the small length and time scales associated with the nucleation process make it very difficult to experimentally determine the molecular level changes that lead to the nucleation event. Conversely, for this reason, there have been increasing efforts to obtain this information using molecular simulations. Accurate knowledge of how and when hydrate structures nucleate will be tremendously beneficial for the development of sustainable hydrate management strategies in oil and gas flowlines, as well as for their application in energy storage and recovery, gas separation, carbon sequestration, seawater desalination, and refrigeration. This article reviews various aspects of hydrate nucleation. First, properties of supercooled water and ice nucleation are reviewed briefly due to their apparent similarity to hydrates. Hydrate nucleation is then reviewed starting from macroscopic observations as obtained from experiments in laboratories and operations in industries, followed by various hydrate nucleation hypotheses and hydrate nucleation driving force calculations based on the classical nucleation theory. Finally, molecular simulations on hydrate nucleation are discussed in detail followed by potential future research directions.

Comparison of organic emissions from laboratory and full-scale thermal degradation of sewage sludge

International Nuclear Information System (INIS)

Tirey, D.A.; Striebich, R.C.; Dellinger, B.; Bostian, H.E.

1991-01-01

Samples of sewage sludge burned at one fluidized-bed and three multiple-hearth incinerators were subjected to laboratory flow reactor thermal decomposition testing in both pyrolytic and oxidative atmospheres. The time/temperature conditions of the laboratory testing were established to simulate as closely as possible full-scale incineration conditions so that a direct comparison of results could be made. The laboratory test results indicated that biomass decomposition products, not toxic industrial contaminants, comprised the majority of the emissions. Benzene, toluene, ethylbenzene, acrylonitrile, and acetonitrile were consistently the most environmentally significant products of thermal degradation. Comparison of the results from this study with those obtained in field tests was complicated by an apparent loss of volatile chlorocarbons from the sludge samples received for laboratory testing. However, qualitative comparison of emission factors derived from lab and field results for those compounds observed in both studies, showed reasonably good correlation for the pyrolysis testing. Results suggested that the upper stages of multiple-hearth units may vaporize many volatile components of the sludge before they enter the combustion stages of the incinerator and thus represent a direct source of introduction of pollutants into the atmosphere

Exogenous origin of hydration on asteroid (16) Psyche: the role of hydrated asteroid families

Science.gov (United States)

Avdellidou, C.; Delbo', M.; Fienga, A.

2018-04-01

Asteroid (16) Psyche, which for a long time was the largest M-type with no detection of hydration features in its spectrum, was recently discovered to have a weak 3-μm band and thus it was eventually added to the group of hydrated asteroids. Its relatively high density, in combination with the high radar albedo, led researchers to classify the asteroid as a metallic object. It is believed that it is possibly a core of a differentiated body, a remnant of `hit-and-run' collisions. The detection of hydration is, in principle, inconsistent with a pure metallic origin for this body. Here, we consider the scenario in which the hydration on its surface is exogenous and was delivered by hydrated impactors. We show that impacting asteroids that belong to families whose members have the 3-μm band can deliver hydrated material to Psyche. We developed a collisional model with which we test all dark carbonaceous asteroid families, which contain hydrated members. We find that the major source of hydrated impactors is the family of Themis, with a total implanted mass on Psyche of the order of ˜1014 kg. However, the hydrated fraction could be only a few per cent of the implanted mass, as the water content in carbonaceous chondrite meteorites, the best analogue for the Themis asteroid family, is typically a few per cent of their mass.

Fermentative biohydrogen and biomethane co-production from mixture of food waste and sewage sludge: Effects of physiochemical properties and mix ratios on fermentation performance

International Nuclear Information System (INIS)

Cheng, Jun; Ding, Lingkan; Lin, Richen; Yue, Liangchen; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

2016-01-01

Highlights: • Microanalyses revealed food waste had more gelatinized organics and less mineral ash. • Mixed food waste and sewage sludge at 5 ratios were used for H_2 and CH_4 co-production. • Highest H_2 yield of 174.6 mL/gVS was achieved when food waste:sewage sludge was 3:1. • Co-fermentation enhanced carbon conversion by strengthening hydrolysis of substrates. • Energy yield rose from 1.9 kJ/gVS in H_2 to 11.3 kJ/gVS in H_2 and CH_4 co-production. - Abstract: The accumulation of increasingly generated food waste and sewage sludge is currently a heavy burden on environment in China. In this study, the physiochemical properties of food waste and sewage sludge were identified using scanning electron microscopy and Fourier transform infrared spectroscopy to investigate the effects on the fermentation performance in the co-fermentation of food waste and sewage sludge for biohydrogen production. The high gelatinized organic components in food waste, the enhanced bioaccessibility due to the dilution of mineral compounds in sewage sludge, and the balanced C/N ratio synergistically improved the fermentative biohydrogen production through the co-fermentation of food waste and sewage sludge at a volatile solids (VS) mix ratio of 3:1. The biohydrogen yield of 174.6 mL/gVS was 49.9% higher than the weighted average calculated from mono-fermentation of food waste and sewage sludge. Co-fermentation also strengthened the hydrolysis and acidogenesis of the mixture, resulting in a total carbon conversion efficiency of 63.3% and an energy conversion efficiency of 56.6% during biohydrogen production. After the second-stage anaerobic digestion of hydrogenogenic effluent, the energy yield from the mixed food waste and sewage sludge significantly increased from 1.9 kJ/gVS in the first-stage biohydrogen production to 11.3 kJ/gVS in the two-stage fermentative biohydrogen and biomethane co-production.

Efficiency of Worm Reactors in Reducing Sludge Volume in Activated Sludge Systems

Directory of Open Access Journals (Sweden)

Azam Naderi

2017-01-01

Full Text Available The activated sludge process is the most widely used on a global scale for the biological treatment of both domestic and industrial effluents. One problem associated with the process, however, is the high volume of sludge produced. Excess sludge treatment and disposal account for up to 60% of the total operating costs of urban wastewater treatment plants due to the stringent environmental regulations on excess sludge disposal. These strict requirements have encouraged a growing interest over the last few years in reducing sludge volumes produced at biological treatment plants and a number of physical, chemical, and mechanical methods have been accordingly developed for this purpose. The proposed methods are disadvantaged due to their rather high investment and operation costs. An alternative technology that avoids many of these limitations is the worm reactor. In this study, the characteristics of this technology are investigated while the related literature is reviewed to derive the optimal conditions for the operation of this process in different situations.

Perspectives of recycling gamma irradiated sewage-sludge in agricultural applications: a study on methi (Trigonella foenum-graecum L. :leguminosae)

Energy Technology Data Exchange (ETDEWEB)

Pandya, G A; Banerjee, S; Modi, V V [Baroda Univ. (India). Faculty of Science

1991-01-01

The effects of gamma-irradiated sludge on the growth and yield of methi (Trigonella foenum-graecum L.) in pot cultures have been studied. The gamma-irradiated sludge appeared to negatively affect the physical growth parameters of the plant. The significant positive effect of gamma-irradiated sludge was observed on the biochemical growth parameters and yield of methi plants. There was a 3.5-, 1.7- and 2-fold increase in the total protein content, total soluble sugars and starch content, respectively, of plants grown in soil supplemented with gamma-irradiated sludge after 45 days of growth. The gamma-irradiated sludge did not show any detrimental effect on any of the three biochemical parameters studied, even after 90 days of plant growth. The sludge obtained from the conventional treatment process was found to be inhibitory to the protein and starch content of plants in the latter stages of plant growth. A significant increase in the yield of methi plants, after 45 as well as 90 days, grown in the presence of gamma-irradiated sludge indicates a beneficial effect of recycling of irradiated sludge for agricultural applications. (author).

Perspectives of recycling gamma irradiated sewage-sludge in agricultural applications: a study on methi (Trigonella foenum-graecum L.:leguminosae)

International Nuclear Information System (INIS)

Pandya, G.A.; Banerjee, S.; Modi, V.V.

1991-01-01

The effects of gamma-irradiated sludge on the growth and yield of methi (Trigonella foenum-graecum L.) in pot cultures have been studied. The gamma-irradiated sludge appeared to negatively affect the physical growth parameters of the plant. The significant positive effect of gamma-irradiated sludge was observed on the biochemical growth parameters and yield of methi plants. There was a 3.5-, 1.7- and 2-fold increase in the total protein content, total soluble sugars and starch content, respectively, of plants grown in soil supplemented with gamma-irradiated sludge after 45 days of growth. The gamma-irradiated sludge did not show any detrimental effect on any of the three biochemical parameters studied, even after 90 days of plant growth. The sludge obtained from the conventional treatment process was found to be inhibitory to the protein and starch content of plants in the latter stages of plant growth. A significant increase in the yield of methi plants, after 45 as well as 90 days, grown in the presence of gamma-irradiated sludge indicates a beneficial effect of recycling of irradiated sludge for agricultural applications. (author)

Methane Hydrates: Chapter 8

Science.gov (United States)

Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

2008-01-01

Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be

In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

Science.gov (United States)

Lee, M.W.; Collett, T.S.

2011-01-01

In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

Radioresistance of microorganisms in sewage sludge with special regard to the virus species

International Nuclear Information System (INIS)

Mayr, A.; Mahnel, H.; Brodorotti, H.S. v.; Ottis, K.

1979-01-01

Of the viral species present in surface and waste water only entero-, reo-, parvo-, and possibly paramyxoviruses are of relevance. These viruses remain infectious through to the sewage sludge stage, although then only present in small numbers. Bacteria and moulds are present in high concentrations in sewage sludge, the majority being non-pathogenis or only facultative pathogenic species. Of these only Salmonellae are of public health concern. Viruses are considerably more radiation resistant than bacteria and moulds. In sewage sludge a parvo virus was clearly the most resistant towards radiation followed, in order of decreasing resistivity, by reo- and entero-viruses. With the exception of the strongly resistant streptococcus faecalis two enterobacteria and one mould were found to be relatively radiation-sensitive. Gamma radiation is effective for inactivating all viral and bacterial contamination of sewage sludge. The dose required depends upon the radiation resistance and concentration of the individual strain. Enteroviral elimination determines the dose required for viruses and salmonella radiation the dose for bacteria. For practical sewage sludge decontamination a total irradiation dose of 500 krad has been calculated to meet normal requirements, and this dose can be raised to 1 Mrad for more stringent demands. (orig./MG) [de

Mathematical model of the methane replacement by carbon dioxide in the gas hydrate reservoir taking into account the diffusion kinetics

Science.gov (United States)

Musakaev, N. G.; Khasanov, M. K.; Rafikova, G. R.

2018-03-01

The problem of the replacement of methane in its hydrate by carbon dioxide in a porous medium is considered. The gas-exchange kinetics scheme is proposed in which the intensity of the process is limited by the diffusion of CO2 through the hydrate layer formed between the gas mixture flow and the CH4 hydrate. Dynamics of the main parameters of the process is numerically investigated. The main characteristic stages of the process are determined.

Important operational parameters of membrane bioreactor-sludge disintegration (MBR-SD) system for zero excess sludge production.

Science.gov (United States)

Yoon, Seong-Hoon

2003-04-01

In order to prevent excess sludge production during wastewater treatment, a membrane bioreactor-sludge disintegration (MBR-SD) system has been introduced, where the disintegrated sludge is recycled to the bioreactor as a feed solution. In this study, a mathematical model was developed by incorporating a sludge disintegration term into the conventional activated sludge model and the relationships among the operational parameters were investigated. A new definition of F/M ratio for the MBR-SD system was suggested to evaluate the actual organic loading rate. The actual F/M ratio was expected to be much higher than the apparent F/M ratio in MBR-SD. The kinetic parameters concerning the biodegradability of organics hardly affect the system performance. Instead, sludge solubilization ratio (alpha) in the SD process and particulate hydrolysis rate constant (k(h)) in biological reaction determine the sludge disintegration number (SDN), which is related with the overall economics of the MBR-SD system. Under reasonable alpha and k(h) values, SDN would range between 3 and 5 which means the amount of sludge required to be disintegrated would be 3-5 times higher for preventing a particular amount of sludge production. Finally, normalized sludge disintegration rate (q/V) which is needed to maintain a certain level of MLSS in the MBR-SD system was calculated as a function of F/V ratio.

STUDY ON MAXIMUM SPECIFIC SLUDGE ACIVITY OF DIFFERENT ANAEROBIC GRANULAR SLUDGE BY BATCH TESTS

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

The maximum specific sludge activity of granular sludge from large-scale UASB, IC and Biobed anaerobic reactors were investigated by batch tests. The limitation factors related to maximum specific sludge activity (diffusion, substrate sort, substrate concentration and granular size) were studied. The general principle and procedure for the precise measurement of maximum specific sludge activity were suggested. The potential capacity of loading rate of the IC and Biobed anaerobic reactors were analyzed and compared by use of the batch tests results.

Novel understanding of calcium silicate hydrate from dilute hydration

KAUST Repository

Zhang, Lina

2017-05-13

The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.

Formation of submarine gas hydrates

Energy Technology Data Exchange (ETDEWEB)

Soloviev, V.; Ginsburg, G.D. (Reserch Institute of Geology and Mineral Resources of the Ocean ' ' VNII Okeangeologia' ' , St. Petersburg (Russian Federation))

1994-03-01

Submarine gas hydrates have been discoverd in the course of deep-sea drilling (DSDP and ODP) and bottom sampling in many offshore regions. This paper reports on expeditions carried out in the Black, Caspian and Okhotsk Seas. Gas hydrate accumulations were discovered and investigated in all these areas. The data and an analysis of the results of the deep-sea drilling programme suggest that the infiltration of gas-bearing fluids is a necessary condition for gas hydrate accumulation. This is confirmed by geological observations at three scale levels. Firstly, hydrates in cores are usually associated with comparatively coarse-grained, permeable sediments as well as voids and fractures. Secondly, hydrate accumulations are controlled by permeable geological structures, i.e. faults, diapirs, mud volcanos as well as layered sequences. Thirdly, in the worldwide scale, hydrate accumulations are characteristic of continental slopes and rises and intra-continental seas where submarine seepages also are widespread. Both biogenic and catagenic gas may occur, and the gas sources may be located at various distances from the accumulation. Gas hydrates presumably originate from water-dissolved gas. The possibility of a transition from dissolved gas into hydrate is confirmed by experimental data. Shallow gas hydrate accumulations associated with gas-bearing fluid plumes are the most convenient features for the study of submarine hydrate formation in general. These accumulations are known from the Black, Caspian and Okhotsk Seas, the Gulf of Mexico and off northern California. (au) (24 refs.)

Composting of sewage sludge irradiated

International Nuclear Information System (INIS)

Hashimoto, Shoji; Watanabe, Hiromasa; Nishimura, Koichi; Kawakami, Waichiro

1981-01-01

Recently, the development of the techniques to return sewage sludge to forests and farm lands has been actively made, but it is necessary to assure its hygienic condition lest the sludge is contaminated by pathogenic bacteria. The research to treat sewage sludge by irradiation and utilize it as fertilizer or soil-improving material has been carried out from early on in Europe and America. The effects of the irradiation of sludge are sterilization, to kill parasites and their eggs, the inactivation of weed seeds and the improvement of dehydration. In Japan, agriculture is carried out in the vicinity of cities, therefore it is not realistic to use irradiated sludge for farm lands as it is. The composting treatment of sludge by aerobic fermentation is noticed to eliminate the harms when the sludge is returned to forests and farm lands. It is desirable to treat sludge as quickly as possible from the standpoint of sewage treatment, accordingly, the speed of composting is a problem. The isothermal fermentation experiment on irradiated sludge was carried out using a small-scale fermentation tank and strictly controlling fermentation conditions, and the effects of various factors on the fermentation speed were studied. The experimental setup and method are described. The speed of composting reached the maximum at 50 deg C and at neutral or weak alkaline pH. The speed increased with the increase of irradiation dose up to 30 Mrad. (Kako, I.)

K Basin sludge dissolution engineering study

International Nuclear Information System (INIS)

Westra, A.G.

1998-01-01

The purpose of this engineering study is to investigate the available technology related to dissolution of the K Basin sludge in nitric acid. The conclusion of this study along with laboratory and hot cell tests with actual sludge samples will provide the basis for beginning conceptual design of the sludge dissolver. The K Basin sludge contains uranium oxides, fragments of metallic U, and some U hydride as well as ferric oxyhydroxide, aluminum oxides and hydroxides, windblown sand that infiltrated the basin enclosure, ion exchange resin, and miscellaneous materials. The decision has been made to dispose of this sludge separate from the fuel elements stored in the basins. The sludge will be conditioned so that it meets Tank Waste Remediation System waste acceptance criteria and can be sent to one of the underground storage tanks. Sludge conditioning will be done by dissolving the fuel constituents in nitric acid, separating the insoluble material, adding neutron absorbers for criticality safety, and then reacting the solution with caustic to co-precipitate the uranium and plutonium. There will be five distinct feed streams to the sludge conditioning process two from the K East (KE) Basin and three from the K West (KW) Basin. The composition of the floor and pit sludges which contain more iron oxides and sand than uranium is much different than the canister sludges which are composed of mostly uranium oxides. The sludge conditioning equipment will be designed to process all of the sludge streams, but some of the operating parameters will be adjusted as necessary to handle the different sludge stream compositions. The volume of chemical additions and the amount of undissolved solids will be much different for floor and pit sludge than for canister sludge. Dissolution of uranium metal and uranium dioxide has been studied quite thoroughly and much information is available. Both uranium metal and uranium dioxide have been dissolved on a large scale in nuclear fuel

The effect of operational conditions on the sludge specific methanogenic activity and sludge biodegradability

International Nuclear Information System (INIS)

Leitao, R. C.; Santaella, S. T.; Haandel, A. C. van; Zeeman, G.; Lettinga, G.

2009-01-01

The Specific Methanogenic Activity (SMA) and sludge biodegradability of an anaerobic sludge depends on various operational and environmental conditions imposed to the anaerobic reactor. However, the effects of hydraulic retention time (HRT), influent COD concentration (COD i nf) and sludge retention time (SRT) on those two parameters need to be elucidated. This knowledge about SMA can provide insights about the capacity of the UASB reactors to withstand organic and hydraulic shock loads, whereas the biodegradability gives information necessary for final disposal of the sludge. (Author)

The effect of operational conditions on the sludge specific methanogenic activity and sludge biodegradability

Energy Technology Data Exchange (ETDEWEB)

Leitao, R. C.; Santaella, S. T.; Haandel, A. C. van; Zeeman, G.; Lettinga, G.

2009-07-01

The Specific Methanogenic Activity (SMA) and sludge biodegradability of an anaerobic sludge depends on various operational and environmental conditions imposed to the anaerobic reactor. However, the effects of hydraulic retention time (HRT), influent COD concentration (COD{sub i}nf) and sludge retention time (SRT) on those two parameters need to be elucidated. This knowledge about SMA can provide insights about the capacity of the UASB reactors to withstand organic and hydraulic shock loads, whereas the biodegradability gives information necessary for final disposal of the sludge. (Author)

Characterization of un-hydrated and hydrated BioAggregate™ and MTA Angelus™.

Science.gov (United States)

Camilleri, J; Sorrentino, F; Damidot, D

2015-04-01

BioAggregate™ is a novel material introduced for use as a root-end filling material. It is tricalcium silicate-based, free of aluminium and uses tantalum oxide as radiopacifier. BioAggregate contains additives to enhance the material performance. The purpose of this research was to characterize the un-hydrated and hydrated forms of BioAggregate using a combination of techniques, verify whether the additives if present affect the properties of the set material and compare these properties to those of MTA Angelus™. Un-hydrated and hydrated BioAggregate and MTA Angelus were assessed. Un-hydrated cement was tested for chemical composition, specific surface area, mineralogy and kinetics of hydration. The set material was investigated for mineralogy, microstructure and bioactivity. Scanning electron microscopy, X-ray energy dispersive spectroscopic analysis, X-ray fluorescence spectroscopy, X-ray diffraction and isothermal calorimetry were employed. The specific surface area was investigated using a gas adsorption method with nitrogen as the probe. BioAggregate was composed of tricalcium silicate, tantalum oxide, calcium phosphate and silicon dioxide and was free of aluminium. On hydration, the tricalcium silicate produced calcium silicate hydrate and calcium hydroxide. The former was deposited around the cement grains, while the latter reacted with the silicon dioxide to form additional calcium silicate hydrate. This resulted in reduction of calcium hydroxide in the aged cement. MTA Angelus reacted in a similar fashion; however, since it contained no additives, the calcium hydroxide was still present in the aged cement. Bioactivity was demonstrated by deposition of hydroxyapatite. BioAggregate exhibited a high specific surface area. Nevertheless, the reactivity determined by isothermal calorimetry appeared to be slow compared to MTA Angelus. The tantalum oxide as opposed to bismuth oxide was inert, and tantalum was not leached in solution. BioAggregate exhibited

Electron beam disinfection of sewage sludge

International Nuclear Information System (INIS)

Hashimoto, Shoji

1992-01-01

Electron beam treatment of dehydrated sewage sludge for safe reutilization was performed. Ranges of total bacterial counts and total coliforms in the sludge were from 1.5 x 10 8 to 1.6 x 10 9 and from 2.2 x 10 7 to 1.5 x 10 8 per wet gram, respectively. Total bacterial counts decreased about 5 log cycles after irradiating 5 kGy and irradiation with 2 kGy was enough to kill all coliforms in sewage sludge. The survival curves of total bacteria, obtained by irradiation in oxygen atmosphere, approached to that in nitrogen atmosphere with the increase of sludge thickness. No effects of dose rate and electron energy were found when the sludge layers were thin enough. Continuous disinfection of sewage sludge cake, with the maximum feed rate of 300 kg-sludge/hr, was successfully performed with a Cockcroft-Walton type electron accelerator, a sludge pump and a flat nozzle. (J.P.N.)

Dewatering properties of differently treated sewage sludge

International Nuclear Information System (INIS)

Zehnder, H.J.

1977-01-01

A study on dewatering properties of radiosterilized sewage sludge of different type and origin was carried out. For comparison, also heat-treated (pasteurized) sludge was investigated. The specific filtration resistance of irradiated sewage sludge was lowered in all types of sludge examined. In general, pasteurization increased this parameter. The settling properties of irradiated digested sewage sludge was slightly improved, mainly in the first hours after treatment. Microbial effects may mask the real sedimentation relations especcially in aerobically stabilized sludges. A pasteurization treatment of sewage sludge caused an increased content of soluble substances and suspended particles in the supernatant water. The supernatant water from irradiated sludge showed a smaller increase

Composting of gamma-radiation disinfected sewage sludge

International Nuclear Information System (INIS)

Kawakami, W.; Hashimoto, S.; Watanabe, H.; Nishimura, K.; Watanabe, H.; Ito, H.; Takehisa, M.

1981-01-01

The composting of radiation disinfected sewage sludge has been studied since 1978, aiming to present a new process of sludge composting for agricultural uses. This process is composed of two steps: irradiation step to disinfect sludge, and composting step to remove odor and easily decomposable organics in sludge. In this paper, the gamma-irradiation effect on sludge cake and composting condition of irradiated sludge are discussed. (author)

Methods to determine hydration states of minerals and cement hydrates

Energy Technology Data Exchange (ETDEWEB)

Baquerizo, Luis G., E-mail: luis.baquerizoibarra@holcim.com [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Matschei, Thomas [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Scrivener, Karen L. [Laboratory of Construction Materials, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Saeidpour, Mahsa; Thorell, Alva; Wadsö, Lars [Building Materials, Lund University, Box 124, 221 000 Lund (Sweden)

2014-11-15

This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i.e. varying molar water contents). The multi-method approach developed here is capable of deriving physico-chemical boundary conditions and the thermodynamic properties of hydrated phases, many of which are currently missing from or insufficiently reported in the literature. As an example the approach was applied to monosulfoaluminate, a phase typically found in hydrated cement pastes. New data on the dehydration and rehydration of monosulfoaluminate are presented. Some of the methods used were validated with the system Na{sub 2}SO{sub 4}–H{sub 2}O and new data related to the absorption of water by anhydrous sodium sulfate are presented. The methodology and data reported here should permit better modeling of the volume stability of cementitious systems exposed to various different climatic conditions.

Methods to determine hydration states of minerals and cement hydrates

International Nuclear Information System (INIS)

Baquerizo, Luis G.; Matschei, Thomas; Scrivener, Karen L.; Saeidpour, Mahsa; Thorell, Alva; Wadsö, Lars

2014-01-01

This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i.e. varying molar water contents). The multi-method approach developed here is capable of deriving physico-chemical boundary conditions and the thermodynamic properties of hydrated phases, many of which are currently missing from or insufficiently reported in the literature. As an example the approach was applied to monosulfoaluminate, a phase typically found in hydrated cement pastes. New data on the dehydration and rehydration of monosulfoaluminate are presented. Some of the methods used were validated with the system Na 2 SO 4 –H 2 O and new data related to the absorption of water by anhydrous sodium sulfate are presented. The methodology and data reported here should permit better modeling of the volume stability of cementitious systems exposed to various different climatic conditions

Combined Pre-Precipitation, Biological Sludge Hydrolysis and Nitrogen Reduction - A Pilot Demonstration of Integrated Nutrient Removal

DEFF Research Database (Denmark)

Kristensen, G. H.; Jørgensen, P. E.; Strube, R.

1992-01-01

solubilization was 10-13% of the suspended COD. The liquid phase of the hydrolyzed sludge, the hydrolysate, was separated from the suspended fraction by centrifugation and added to the biological nitrogen removal stage to support denitrification. The hydrolysate COD consisted mainly of volatile fatty acids......A pilot study was performed to investigate advanced wastewater treatment by pre-precipitation in combination with biological nitrogen removal supported by biological sludge hydrolysis. The influent wastewater was pretreated by addition of a pre-polymerized aluminum salt, followed by flocculation......, resulting in high denitrification rates. Nitrogen reduction was performed based on the Bio-Denitro principle in an activated sludge system. Nitrogen was reduced from 45 mg/l to 9 mg/l and phosphorus was reduced from 11 mg/l to 0.5 mg/l. The sludge yield was low, approx. 0.3-0.4 gCOD/gCOD removed...

Enthalpy of dissociation and hydration number of methane hydrate from the Clapeyron equation

International Nuclear Information System (INIS)

Anderson, Graydon K.

2004-01-01

The enthalpies of the reactions in which methane hydrate is dissociated to methane vapor and either (1) water, or (2) ice are determined by a new analysis using the Clapeyron equation. The difference in enthalpies of the two reactions is used to infer the hydration number at the quadruple point where hydrate, ice, liquid water, and methane vapor coexist. By appropriate corrections, the hydration number at points removed from the quadruple point is also determined. The most important feature of the new analysis is the direct use of the Clapeyron equation. The method avoids the use of certain simplifying assumptions that have compromised the accuracy of previous analyses in which the Clausius-Clapeyron equation was used. The analysis takes into account the finite volumes of all phases, the non-ideality of the vapor phase, and the solubility of methane in water. The results show that the enthalpy of dissociation and hydration number are constant within experimental error over the entire (hydrate, liquid, vapor) coexistence region. The results are more accurate than but entirely consistent with almost all previous studies

Ultrasonic sludge pretreatment under pressure.

Science.gov (United States)

Le, Ngoc Tuan; Julcour-Lebigue, Carine; Delmas, Henri

2013-09-01

The objective of this work was to optimize the ultrasound (US) pretreatment of sludge. Three types of sewage sludge were examined: mixed, secondary and secondary after partial methanisation ("digested" sludge). Thereby, several main process parameters were varied separately or simultaneously: stirrer speed, total solid content of sludge (TS), thermal operating conditions (adiabatic vs. isothermal), ultrasonic power input (PUS), specific energy input (ES), and for the first time external pressure. This parametric study was mainly performed for the mixed sludge. Five different TS concentrations of sludge (12-36 g/L) were tested for different values of ES (7000-75,000 kJ/kgTS) and 28 g/L was found as the optimum value according to the solubilized chemical oxygen demand in the liquid phase (SCOD). PUS of 75-150 W was investigated under controlled temperature and the "high power input - short duration" procedure was the most effective at a given ES. The temperature increase in adiabatic US application significantly improved SCOD compared to isothermal conditions. With PUS of 150 W, the effect of external pressure was investigated in the range of 1-16 bar under isothermal and adiabatic conditions for two types of sludge: an optimum pressure of about 2 bar was found regardless of temperature conditions and ES values. Under isothermal conditions, the resulting improvement of sludge disintegration efficacy as compared to atmospheric pressure was by 22-67% and 26-37% for mixed and secondary sludge, respectively. Besides, mean particle diameter (D[4,3]) of the three sludge types decreased respectively from 408, 117, and 110 μm to about 94-97, 37-42, and 36-40 μm regardless of sonication conditions, and the size reduction process was much faster than COD extraction. Copyright © 2013 Elsevier B.V. All rights reserved.

Rheological properties of disintegrated sewage sludge

Science.gov (United States)

Wolski, Paweł

2017-11-01

The rheology of the sludge provides information about the capacity and the flow, which in the case of project tasks for the hydraulic conveying installation is an important control parameter. Accurate knowledge of the rheological properties of sludge requires the designation of rheological models. Models single and multiparameter (Ostwald, Bingham, Herschel-Bulkley'a, and others) allow an approximation of flow curves, and the determination of the boundaries of the flow of modified sludge allows you to control the process compaction or are dewatered sludge undergoing flow. The aim of the study was to determine the rheological parameters and rheological models of sludge conditioned by physical methods before and after the process of anaerobic digestion. So far, studies have shown that the application of conditioning in the preparation of sewage sludge increases shear stress, viscosity as well as the limits of flow in relation to the untreated sludge. Offset yield point by the application of a conditioning agent is associated with decreased flowability tested sludge, which has also been observed by analyzing the structure of the prepared samples. Lowering the yield point, and thus the shear stress was recorded as a result of the fermentation test of disintegrated sludge.

Fire extinction utilizing carbon dioxide hydrate

Energy Technology Data Exchange (ETDEWEB)

Hatakeyama, T.; Aida, E.; Yokomori, T.; Ohmura, R.; Ueda, T. [Keio Univ., Hiyoshi, Kohoku-ku, Yokohama (Japan)

2008-07-01

Clathrate hydrates formed with nonflammable gases may be suitable for use as fire extinguishing agents because dissociation of the hydrates results in the temperature decrease in the combustion field and the nonflammable gases released from the dissociated hydrates prevent the supply of the oxygen to the combustion field. This paper discussed experiments in which ordinary ice and dry ice were used to evaluate the performance of CO{sub 2} hydrate as a fire extinguishing agent. The paper described the apparatus and procedure for the preparation of CO{sub 2} hydrate crystals. A schematic of the reactor to form CO{sub 2} hydrate and a photograph of CO{sub 2} hydrate crystal formed in the study were also presented. Other illustrations, photographs, and tables that were presented included a schematic diagram of the experimental apparatus used for the flame extinction experiments; a photograph of CO{sub 2} hydrate powder; sequential video graphs of the flame extinction by the supply of CO{sub 2} hydrate crystals to the methanol pool flame and the relevant illustration; and heat of CO{sub 2} hydrate dissociation, water vaporization and sublimation of dry ice. It was concluded that the critical mass of the CO{sub 2} hydrate required to extinguish a flame was much less than that of ordinary ice, indicating the superiority of CO{sub 2} hydrate to the ice. In addition, the experiments also revealed that the size of the CO{sub 2} hydrate particles had a significant effect on the performance of flame extinction. 5 refs., 2 tabs., 7 figs.

Influence of sludge properties and hydraulic loading on the performance of secondary settling tanks--full-scale operational results.

Science.gov (United States)

Vestner, R J; Günthert, F Wolfgang

2004-01-01

Full-scale investigations at a WWTP with a two-stage secondary settling tank process revealed relationships between significant operating parameters and performance in terms of effluent suspended solids concentration. Besides common parameters (e.g. surface overflow rate and sludge volume loading rate) feed SS concentration and flocculation time must be considered. Concentration of the return activated sludge may help to estimate the performance of existing secondary settling tanks.

Hydrates on tap: scientists say natural gas hydrates may be tough nut to crack

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J.

2001-12-01

Gas hydrates are methane molecules trapped in cages of water molecules, yielding a substance with a slushy, sherbet-like consistency. Drilling for hydrates is similar to conventional oil and gas drilling, however, the secret to economic production still remains hidden. Hydrates exist in abundance in such places as deep ocean floor and below ground in some polar regions. The real challenge lies in producing gas from this resource, inasmuch as there is no existing technology for production of gas specifically from methane hydrates. This paper describes an international research program, involving a five-country partnership to spud the first of three wells into the permafrost of the Mackenzie River Delta in the Northwest Territories. The project, worth about $15 million, has brought together public funding and expertise from Japan, Germany, India as well as the Canadian and US Geological Surveys and the US Dept. of Energy in an effort to gain information on the production response of gas hydrates. The operator of the project is Japan Petroleum Exploration Company of Canada, a subsidiary of Japan National Oil Corporation. Since Japan is poor in domestic hydrocarbon resources, but is surrounded by deep water that contains potential for gas hydrates, Japan has a great deal riding on the success of this project. Germany and the United States are also very much interested. Current thinking is that gas is in contact with the hydrates and that it should be possible to develop a free gas reservoir as if it were a conventional deposit. As the free gas is drawn off, the pressure is reduced on the hydrates in contact with it , the hydrates dissociate from the gas and replenish the conventional reservoir. So far this is still only a theory, but it appears to be a sensible approach to hydrate production. 1 photo.

Dewatering of sludges

International Nuclear Information System (INIS)

Bode, P.

1984-01-01

A filter rig has been designed and built. Simulated magnox and alumino ferric hydroxide sludges have been successfully filtered on this equipment and both types of sludge produced a clear filtrate and a cake. The flow rates were low. The cake often partially remained adhered to the filter membrane instead of dropping clear during the filter cleaning cycle. This filtration technique can only be used on sludges which form a non-binding cake. Permeability of the membrane can be altered by stretching. Irradiation of the membrane showed that it should withstand 20 to 50 M.rads. (author)

Waters of Hydration of Cupric Hydrates: A Comparison between Heating and Absorbance Methods

Science.gov (United States)

Barlag, Rebecca; Nyasulu, Frazier

2011-01-01

The empirical formulas of four cupric hydrates are determined by measuring the absorbance in aqueous solution. The Beer-Lambert Law is verified by constructing a calibration curve of absorbance versus known Cu[superscript 2+](aq) concentration. A solution of the unknown hydrate is prepared by using 0.2-0.3 g of hydrate, and water is added such…

Methane hydrate dissociation using inverted five-spot water flooding method in cubic hydrate simulator

International Nuclear Information System (INIS)

Li, Gang; Li, Xiao-Sen; Li, Bo; Wang, Yi

2014-01-01

The combination forms of the hydrate dissociation methods in different well systems are divided into 6 main patterns. Dissociation processes of methane hydrate in porous media using the inverted five-spot water flooding method (Pattern 4) are investigated by the experimental observation and numerical simulation. In situ methane hydrate is synthesized in the Cubic Hydrate Simulator (CHS), a 5.832-L cubic reactor. A center vertical well is used as the hot water injection well, while the four vertical wells at the corner are the gas and water production wells. The gas production begins simultaneously with the hot water injection, while after approximately 20 min of compression, the water begins to be produced. One of the common characteristics of the inverted five-spot water flooding method is that both the gas and water production rates decrease with the reduction of the hydrate dissociation rate. The evaluation of the energy efficiency ratio might indicate the inverted five-spot water flooding as a promising gas producing method from the hydrate reservoir. - Highlights: • A three-dimensional 5.8-L cubic pressure vessel is developed. • Gas production of hydrate using inverted five-spot flooding method is studied. • Water/gas production rate and energy efficiency ratio are evaluated. • Temperature distributions of numerical simulation and experiment agree well. • Hydrate dissociation process is a moving boundary problem in this study

[Effect of different sludge retention time (SRT) on municipal sewage sludge bioleaching continuous plug flow reaction system].

Science.gov (United States)

Liu, Fen-Wu; Zhou, Li-Xiang; Zhou, Jun; Jiang, Feng; Wang, Dian-Zhan

2012-01-01

A plug-flow bio-reactor of 700 L working volume for sludge bioleaching was used in this study. The reactor was divided into six sections along the direction of the sludge movement. Fourteen days of continuous operation of sludge bioleaching with different sludge retention time (SRT) under the condition of 1.2 m3 x h(-1) aeration amount and 4 g x L(-1) of microbial nutritional substance was conducted. During sludge bioleaching, the dynamic changes of pH, DO, dewaterability (specific resistance to filtration, SRF) of sewage sludge in different sections were investigated in the present study. The results showed that sludge pH were maintained at 5.00, 3.00, 2.90, 2.70, 2.60 and 2.40 from section 1 to section 6 and the SRF of sludge was drastically decreased from initial 0.64 x 10(13) m x kg(-1) to the final 0.33 x 10(13) m x kg(-1) when bioleaching system reached stable at hour 72 with SRT 2.5d. In addition, the sludge pH were maintained at 5.10, 4.10, 3.20, 2.90, 2.70 and 2.60, the DO value were 0.43, 1.47, 3.29, 4.76, 5.75 and 5.88 mg x L(-1) from section 1 to section 6, and the SRF of sludge was drastically decreased from initial 0.56 x 10(13) to the final 0.20 x 10(13) m x kg(-1) when bioleaching system reached stable at hour 120 with SRT 2 d. The pH value was increased to 3.00 at section 6 at hour 48 h with SRT 1.25 d. The bioleaching system imbalanced in this operation conditions because of the utilization efficiency of microbial nutritional substance by Acidibacillus spp. was decreased. The longer sludge retention time, the easier bioleaching system reached stable. 2 d could be used as the optimum sludge retention time in engineering application. The bioleached sludge was collected and dewatered by plate-and-frame filter press to the moisture content of dewatered sludge cake under 60%. This study would provide the necessary data to the engineering application on municipal sewage sludge bioleaching.

Sludge pumping in water treatment

International Nuclear Information System (INIS)

Solar Manuel, M. A.

2010-01-01

In water treatment processes is frequent to separate residual solids, with sludge shape, and minimize its volume in a later management. the technologies to applicate include pumping across pipelines, even to long distance. In wastewater treatment plants (WWTP), the management of these sludges is very important because their characteristics affect load losses calculation. Pumping sludge can modify its behavior and pumping frequency can concern treatment process. This paper explains advantages and disadvantages of different pumps to realize transportation sludge operations. (Author) 11 refs.

In situ monitoring of the hydration process of K-PS geopolymer cement with ESEM

International Nuclear Information System (INIS)

Sun Wei; Zhang Yunsheng; Lin Wei; Liu Zhiyong

2004-01-01

Environmental scanning electron microscope (ESEM) was used to in situ quantitatively study the hydration process of K-PS geopolymer cement under an 80% RH environment. An energy dispersion X-ray analysis (EDXA) was also employed to distinguish the chemical composition of hydration product. The ESEM micrographs showed that metakaolin particles pack loosely at 10 min after mixing, resulting in the existence of many large voids. As hydration proceeds, a lot of gels were seen and gradually precipitated on the surfaces of these particles. At later stage, these particles were wrapped by thick gel layers and their interspaces were almost completely filled. The corresponding EDXA results illustrated that the molar ratios of K/Al increase while Si/Al decrease with the development of hydration. As a result, the molar ratios of K/Al and Si/Al of hydration products at an age of 4 h amounted to 0.99 and 1.49, respectively, which were close to the theoretical values (K/Al=1.0, Si/Al=1.0 for K-PS geopolymer cement paste). In addition, well-developed crystals could not been found at any ages; instead, spongelike amorphous gels were always been observed

RELATIONSHIP BETWEEN SLUDGE DEWATERABILITY NUMBER ...

African Journals Online (AJOL)

A representative of a sludge sample collected from the same source was filtered under the same environmental condition and the result analysed with two different concepts. One method of analysis uses Sludge Dewaterability Number, while the second employed the Carman's Specific resistance concept in sludge ...

Impact of sludge stabilization processes and sludge origin (urban or hospital) on the mobility of pharmaceutical compounds following sludge landspreading in laboratory soil-column experiments.

Science.gov (United States)

Lachassagne, Delphine; Soubrand, Marilyne; Casellas, Magali; Gonzalez-Ospina, Adriana; Dagot, Christophe

2015-11-01

This study aimed to determine the effect of sludge stabilization treatments (liming and anaerobic digestion) on the mobility of different pharmaceutical compounds in soil amended by landspreading of treated sludge from different sources (urban and hospital). The sorption and desorption potential of the following pharmaceutical compounds: carbamazepine (CBZ), ciprofloxacin (CIP), sulfamethoxazole (SMX), salicylic acid (SAL), ibuprofen (IBU), paracetamol (PAR), diclofenac (DIC), ketoprofen (KTP), econazole (ECZ), atenolol (ATN), and their solid-liquid distribution during sludge treatment (from thickening to stabilization) were investigated in the course of batch testing. The different sludge samples were then landspread at laboratory scale and leached with an artificial rain simulating 1 year of precipitation adapted to the surface area of the soil column used. The quality of the resulting leachate was investigated. Results showed that ibuprofen had the highest desorption potential for limed and digested urban and hospital sludge. Ibuprofen, salicylic acid, diclofenac, and paracetamol were the only compounds found in amended soil leachates. Moreover, the leaching potential of these compounds and therefore the risk of groundwater contamination depend mainly on the origin of the sludge because ibuprofen and diclofenac were present in the leachates of soils amended with urban sludge, whereas paracetamol and salicylic acid were found only in the leachates of soils amended with hospital sludge. Although carbamazepine, ciprofloxacin, sulfamethoxazole, ketoprofen, econazole, and atenolol were detected in some sludge, they were not present in any leachate. This reflects either an accumulation and/or (bio)degradation of these compounds (CBZ, CIP, SMX, KTP, ECZ, and ATN ), thus resulting in very low mobility in soil. Ecotoxicological risk assessment, evaluated by calculating the risk quotients for each studied pharmaceutical compound, revealed no high risk due to the

Formation rate of natural gas hydrate

Energy Technology Data Exchange (ETDEWEB)

Mork, Marit

2002-07-01

The rate of methane hydrate and natural gas hydrate formation was measured in a 9.5 litre stirred tank reactor of standard design. The experiments were performed to better understand the performance and scale-up of a reactor for continuous production of natural gas hydrates. The hydrate formation rate was measured at steady-state conditions at pressures between 70 and 90 bar and temperatures between 7 and 15 deg C. Between 44 and 56 % of the gas continuously supplied to the reactor was converted to hydrate. The experimental results show that the rate of hydrate formation is strongly influenced by gas injection rate and pressure. The effect of stirring rate is less significant and subcooling has no observable effect on the formation rate. Hydrate crystal concentration and gas composition do not influence the hydrate formation rate. Observations of produced hydrate crystals indicate that the crystals are elongated, about 5 micron in diameter and 10 micron long. Analysis of the results shows that the rate of hydrate formation is dominated by gas-liquid mass transfer. A mass transfer model, the bubble-to-crystal model, was developed for the hydrate formation rate in a continuous stirred tank reactor, given in terms of concentration driving force and an overall mass transfer coefficient. The driving force is the difference between the gas concentration at the gas-liquid interface and at the hydrate crystal surface. These concentrations correspond to the solubility of gas in water at experimental temperature and pressure and the solubility of gas at hydrate equilibrium temperature and experimental pressure, respectively. The overall mass transfer coefficient is expressed in terms of superficial gas velocity and impeller power consumption, parameters commonly used in study of stirred tank reactors. Experiments and modeling show that the stirred tank reactor has a considerable potential for increased production capacity. However, at higher hydrate production rates the

[Gradient elevation of temperature startup experiment of thermophilic ASBR treating thermal-hydrolyzed sewage sludge].

Science.gov (United States)

Ouyang, Er-Ming; Wang, Wei; Long, Neng; Li, Huai

2009-04-15

Startup experiment was conducted for thermophilic anaerobic sequencing batch reactor (ASBR) treating thermal-hydrolyzed sewage sludge using the strategy of the step-wise temperature increment: 35 degrees C-->40 degrees C-->47 degrees C-->53 degrees C. The results showed that the first step-increase (from 35 degrees C to 40 degrees C) and final step-increase (from 47 degrees C to 53 degrees C) had only a slight effect on the digestion process. The second step-increase (from 40 degrees C to 47 degrees C) resulted in a severe disturbance: the biogas production, methane content, CODeffluent and microorganism all have strong disturbance. At the steady stage of thermophilic ASBR treating thermal-hydrolyzed sewage sludge, the average daily gas production, methane content, specific methane production (CH4/CODinfluent), TCOD removal rate and SCOD removal rate were 2.038 L/d, 72.0%, 188.8 mL/g, 63.8%, 83.3% respectively. The results of SEM and DGGE indicated that the dominant species are obviously different at early stage and steady stage.

Flow assurance intervention, hydrates remediation

Energy Technology Data Exchange (ETDEWEB)

Mancini, Christopher S. [Oceaneering International Inc., Houston, TX (United States)

2012-07-01

This paper addresses the issues of removing hydrates in sub sea flow lines and associated equipment with an Remotely Operated Vehicle (ROV) of opportunity and a multi-service-vessel (MSV). The paper is split into three topics: the equipment used with the ROV, assessing the interface points and handling fluids produced from drawing down the pressure. Each section is explained thoroughly and backed up with real world experience. The equipment section details information from actual jobs performed and why the particular components were utilized. The system is generally contained in an ROV mounted skid. Pumps are utilized to draw down the pressure inside the hydrated section of equipment, removing one of the three necessary components for hydrates formation. Once the section is pumped down, several options exist for handling the fluids pumped out of the system: pumping to surface, re-injection into the well, or injection into an operating flow line. This method of hydrates remediation is both economical and timely. Hydrate blockages form in low temperatures and high pressures. Reducing the pressure or increasing the temperature so the conditions lie to the right of the hydrate dissociation curve will slowly decompose the blockage. Depressurization and the use of MEG or methanol will give favorable conditions to remove the hydrate plug. Oceaneering has the capabilities to remove hydrates using the FRS in conjunction with an installation vessel to dispose of the gas and fluid removed from the flow line. Hydrate remediation techniques should be implemented into the initial design to reduce costs later. The cost of stopped production combined with the day rate for equipment needed for hydrate removal outweighs the costs if no technique is utilized. (author)

Bench-scale enhanced sludge washing and gravity settling of Hanford Tank C-106 Sludge

International Nuclear Information System (INIS)

Brooks, K.P.; Myers, R.L.; Rappe, K.G.

1997-01-01

This report summarizes the results of a bench-scale sludge pretreatment demonstration of the Hanford baseline flowsheet using liter-quantities of sludge from Hanford Site single-shell tank 241-C-106 (tank C-106). The leached and washed sludge from these tests provided Envelope D material for the contractors supporting Tank Waste Remediation System (TWRS) Privatization. Pretreatment of the sludge included enhanced sludge washing and gravity settling tests and providing scale-up data for both these unit operations. Initial and final solids as well as decanted supernatants from each step of the process were analyzed chemically and radiochemically. The results of this work were compared to those of Lumetta et al. (1996a) who performed a similar experiment with 15 grams of C-106, sludge. A summary of the results are shown in Table S.1. Of the major nonradioactive components, those that were significantly removed with enhanced sludge washing included aluminum (31%), chromium (49%), sodium (57%), and phosphorus (35%). Of the radioactive components, a significant amount of 137 Cs (49%) were removed during the enhanced sludge wash. Only a very small fraction of the remaining radionuclides were removed, including 90 Sr (0.4%) and TRU elements (1.5%). These results are consistent with those of the screening test. All of the supernatants (both individually and as a blend) removed from these washing steps, once vitrified as LLW glasses (at 20 wt% Na 2 O), would be less than NRC Class C in TRU elements and less than NRC Class B in 90 Sr

Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

Science.gov (United States)

Mat Saad, Azlina; Aini Dahalan, Farrah; Ibrahim, Naimah; Yasina Yusuf, Sara; Aqlima Ahmad, Siti; Khalil, Khalilah Abdul

2018-03-01

Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic - anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

Electroosmotic dewatering of chalk sludge, iron hydroxide sludge, wet fly ash and biomass

Energy Technology Data Exchange (ETDEWEB)

Hansen, H.K.; Kristensen, I.V.; Ottosen, L.M.; Villumsen, A. [Dept. of Geology and Geotechnical Engineering, The Technical Univ. of Denmark, Lyngby (Denmark)

2001-07-01

Electroosmotic dewatering has been tested in laboratory cells for 4 different porous materials: chalk sludge, iron hydroxide sludge, wet fly ash and biomass sludge from enzyme production. In all cases it was possible to remove water when passing electric DC current through the material. Casagrande's coefficients for the three materials where determined at different water contents. In the electroosmotic experiments shown in this work chalk can be dewatered from 40% to 79% DM (dry matter), fly ash from 75 to 82% DM, iron hydroxide sludge from 2.7 to 19% DM and biomass from 3 to 33% DM. The process was not optimised indicating that higher dry matter contents could be achieved. (orig.)

Enhancing faecal sludge management in peri-urban areas of Lusaka through faecal sludge valorisation: challenges and opportunities

Science.gov (United States)

Tembo, J. M.; Nyirenda, E.; Nyambe, I.

2017-03-01

Lusaka, the capital city of Zambia, has two million inhabitants with 70% residing in peri-urban areas. Ninety (90) % of this population employ pit latrines for excretion generating approximately 22,680 tons of faecal sludge per annum. This sludge is inadequately managed hence of the generated amount, over 60% remains within the residential environment thereby compromising both the environment and public health. To foster a solution to this problem, a study was commissioned to assess faecal sludge valorisation potential and how it would impact on Faecal Sludge Management. The study evaluated policy, institutional and regulatory frameworks, sanitation practices including latrine construction and usage aspects and also characterised the faecal sludge for selected parameters relevant to valorisation. Four peri-urban areas were adopted as study sites. Policy issues together with existing institutional and regulatory frameworks were assessed through literature review. Sanitation practices were evaluated through physical observations, focus group discussions, interviews and questionnaire administration. Faecal sludge characterisation was through sampling and analysis. It was observed that there are policy gaps in fostering faecal sludge valorisation. Sanitation practices and latrines construction also do not favour valorisation. The quality of the raw sludge has potential for valorisation though again, some parameters like solid waste content require drastic changes in sanitation practices in order not to compromise the reuse potential of the sludge. It was concluded that if faecal sludge management is to be enhanced through valorisation, there is need to have policies promoting pit latrine faecal sludge reuse and strengthened regulatory and institutional frameworks in this respect.

Conversion of sewage sludge to clean solid fuel using hydrothermal carbonization: Hydrochar fuel characteristics and combustion behavior

International Nuclear Information System (INIS)

He, Chao; Giannis, Apostolos; Wang, Jing-Yuan

2013-01-01

Highlights: • The hydrothermal carbonization of sewage sludge process is developed. • Hydrochars are solid fuels with less nitrogen and sulfur contents. • The first order combustion reaction of hydrochars is derived. • Main combustion decomposition of hydrochars is easier and more stable. • Formation pathways of hydrochars during hydrothermal carbonization are proposed. - Abstract: Conventional thermochemical treatment of sewage sludge (SS) is energy-intensive due to its high moisture content. To overcome this drawback, the hydrothermal carbonization (HTC) process was used to convert SS into clean solid fuel without prior drying. Different carbonization times were applied in order to produce hydrochars possessing better fuel properties. After the carbonization process, fuel characteristics and combustion behaviors of hydrochars were evaluated. Elemental analysis showed that 88% of carbon was recovered while 60% of nitrogen and sulfur was removed. Due to dehydration and decarboxylation reactions, hydrogen/carbon and oxygen/carbon atomic ratios reduced to 1.53 and 0.39, respectively. It was found that the fuel ratio increased to 0.18 by prolonging the carbonization process. Besides, longer carbonization time seemed to decrease oxygen containing functional groups while carbon aromaticity structure increased, thereby rendering hydrochars highly hydrophobic. The thermogravimetric analysis showed that the combustion decomposition was altered from a single stage for raw sludge to two stages for hydrochars. The combustion reaction was best fitted to the first order for both raw sludge and hydrochars. The combustion of hydrochars is expected to be easier and more stable than raw sludge because of lower activation energy and pre-exponential factor

Influence of process operating parameters on dryness level and energy saving during wastewater sludge electro-dewatering.

Science.gov (United States)

Mahmoud, Akrama; Hoadley, Andrew F A; Conrardy, Jean-Baptiste; Olivier, Jérémy; Vaxelaire, Jean

2016-10-15

Electrically assisted mechanical dewatering, known as electro-dewatering (EDW), is an alternative emerging technology for energy-efficient liquid/solids separation in the dewatering of wastewater sludge. In this study, the performance of the electro-dewatering (EDW) process for activated wastewater sludge was investigated. The influence of the operating modes; being the timing of voltage (U-EDW) or current (I-EDW) application to either or both the filtration and compression stages, and the influence of the applied pressure (in successive 30 min pressure steps) were studied. The results showed that by delaying the application of the electric field to the filter cake compression stage, there was a potential saving in power consumption of around 10-12% in the case of U-EDW and about 30-46% in the case of I-EDW. The increase of the applied pressure from 0.5 to 12 bar during the filter cake compression stage leads to an increase in electro-dewatering kinetics. The results also reveal that at a low electric field level the increase of the processing pressure has a relatively pronounced effect on the dewatering process. At high levels of the electric field, a minimum processing pressure (4-6 bar) is required to improve the electrical contact between the electrode and the sludge and thus lower the energy consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Indian continental margin gas hydrate prospects : results of the Indian National Gas Hydrate Program (NGHP) expedition 01

Energy Technology Data Exchange (ETDEWEB)

Collett, T [United States Geological Survey, Denver, CO (United States); Riedel, M. [McGill Univ., Montreal, PQ (Canada). Dept. of Earth and Planetary Sciences; Cochran, J.R. [Columbia Univ., Palisades, NY (United States). Lamont Doherty Earth Observatory; Boswell, R. [United States Dept. of Energy, Morgantown, WV (United States). National Energy Technology Lab; Kumar, P. [Pushpendra Kumar Oil and Natural Gas Corp. Ltd., Mumbai (India). Inst. of Engineering and Ocean Technology; Sathe, A.V. [Oil and Natural Gas Corp. Ltd., Uttaranchal (India). KDM Inst. of Petroleum Exploration

2008-07-01

The geologic occurrence of gas hydrate deposits along the continental margins of India were investigated in the first expedition of the Indian National Gas Hydrate Program (NGHP). The objective was to determine the regional context and characteristics of the gas hydrate deposits through scientific ocean drilling, logging, and analytical activities. A research drill ship was the platform for the drilling operation. The geological and geophysical studies revealed 2 geologically distinct areas with inferred gas hydrate occurrences, notably the passive continental margins of the Indian Peninsula and along the Andaman convergent margin. The NGHP Expedition 01 focused on understanding the geologic and geochemical controls on the occurrence of gas hydrate in these 2 diverse settings. The study established the presence of gas hydrates in Krishna-Godavari, Mahanadi and Andaman basins. Site 10 in the Krishna-Godavari Basin was discovered to be the one of the richest gas hydrate accumulations yet documented, while site 17 in the Andaman Sea had the thickest and deepest gas hydrate stability zone yet known. The existence of a fully-developed gas hydrate system in the Mahanadi Basin was also discovered. Most of the gas hydrate occurrences discovered during this expedition appeared to contain mostly methane which was generated by microbial processes. However, there was also evidence of a thermal origin for a portion of the gas within the hydrates of the Mahanadi Basin and the Andaman offshore area. Gas hydrate in the Krishna-Godavari Basin appeared to be closely associated with large scale structural features, in which the flux of gas through local fracture systems, generated by the regional stress regime, controlled the occurrence of gas hydrate. 3 refs., 1 tab., 2 figs.

Development of Magnesium Silicate Hydrate cement system for nuclear waste encapsulation

International Nuclear Information System (INIS)

Zhang, T.; Vandeperre, L.J.; Cheeseman, C.R.

2012-01-01

A novel low pH cement system for encapsulating nuclear industry wastes containing aluminium has been developed using blends of MgO and silica fume (SF). Identification of the hydrated phases in MgO/silica fume samples showed that brucite formed in early stages of hydration and then reacted with the silica fume to produce a magnesium silicate hydrate (M-S-H) gel phase. When all brucite reacts with silica fume a cement system with an equilibrium pH just below 10 was achieved. Selected mixes have been characterized for hydration reactions, setting time and strength development. Mortar samples with w/s ratios of 0.5 and 50% by weight of sand added achieved compressive strengths in excess of 95 MPa after 28 days. The addition of MgCO 3 buffered the early pH and the addition of fine sand particles eliminated shrinkage cracking. The interaction of the optimised mortar with Al metal has been investigated. Al metal strips were firmly bound into the MgO:SF:sand samples and no H 2 gas detected, and this indicates that the novel systems developed in this work have potential for encapsulating certain types of problematic legacy wastes from the nuclear industry. (authors)

Properties of bacterial radioresistance observed in sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Watanabe, H; Ito, H; Takehisa, M [Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment; Iizuka, H

1981-09-01

The changes in radiosensitivities of bacteria in sludge were investigated. The coliforms are more radioresistant in raw sludge than in cake (dewatered sludge). This radioresistance of coliforms was observed not only in raw sludge but also in the cake diluted with water. The radioresistance was independent of the difference of treatment plant, kind of sludge, and season. The oxygen effect on the radioresistance was not observed, but the resistance was changed during storage of sludge. Escherichia coli isolated from sludge was radiosensitive in buffer, but its radiosensitivity was protected by the water-extracts of sludge. On the other hand, radioresistant bacteria were present in total bacteria of sludge irradiated at 2 Mrad. However, the dominant flora in the irradiated sludge consisted of radiosensitive bacteria (mainly Pseudomonas). When a strain of radiosensitive Pseudomonas was irradiated in raw sludge and diluted cake, the radiosensitivity was remarkably protected. From these results, it is suggested that a factor affecting the radiosensitivity of bacteria is present in sludge.

Properties of bacterial radioresistance observed in sewage sludge

International Nuclear Information System (INIS)

Watanabe, Hiroshi; Ito, Hitoshi; Takehisa, Masaaki; Iizuka, Hiroshi.

1981-01-01

The changes in radiosensitivities of bacteria in sludge were investigated. The coliforms are more radioresistant in raw sludge than in cake (dewatered sludge). This radioresistance of coliforms was observed not only in raw sludge but also in the cake diluted with water. The radioresistance was independent of the difference of treatment plant, kind of sludge, and season. The oxygen effect on the radioresistance was not observed, but the resistance was changed during storage of sludge. Escherichia coli isolated from sludge was radiosensitive in buffer, but its radiosensitivity was protected by the water-extracts of sludge. On the other hand, radioresistant bacteria were present in total bacteria of sludge irradiated at 2 Mrad. However, the dominant flora in the irradiated sludge consisted of radiosensitive bacteria (mainly Pseudomonas). When a strain of radiosensitive Pseudomonas was irradiated in raw sludge and diluted cake, the radiosensitivity was remarkably protected. From these results, it is suggested that a factor affecting the radiosensitivity of bacteria is present in sludge. (author)

TECHNOLOGY DEMONSTRATION OF SLUDGE MASS REDUCTION VIA ALUMINUM DISSOLUTION: GLASS FORMULATION PROCESSING WINDOW PREDICTIONS FOR SB5

International Nuclear Information System (INIS)

Fox, K.; Tommy Edwards, T.; David Peeler, D.

2007-01-01

Composition projections for Sludge Batch 5 (SB5) were developed, based on a modeling approach at the Savannah River National Laboratory (SRNL), to evaluate possible impacts of the Al-dissolution process on the availability of viable frit compositions for vitrification at the Defense Waste Processing Facility (DWPF). The study included two projected SB5 compositions that bound potential outcomes (or degrees of effectiveness) of the Al-dissolution process, as well as a nominal SB5 composition projection based on the results of the recent Al-dissolution demonstration at SRNL. The three SB5 projections were the focus of a two-stage paper study assessment. A Nominal Stage assessment combined each of the SB5 composition projections with an array of 19,305 frit compositions over a wide range of waste loading (WL) values and evaluated them against the DWPF process control models. The Nominal Stage results allowed for the down-selection of a small number of frits that provided reasonable projected operating windows (typically 27 to 42 wt% WL). The frit/sludge systems were mostly limited by process related constraints, with only one system being limited by predictions of nepheline crystallization, a waste form affecting constraint. The criteria applied in selecting the frit compositions somewhat restricted the compositional flexibility of the candidate frits for each individual SB5 composition projection, which may limit the ability to further tailor the frit for improved melt rate. Variation Stage assessments were then performed using the down-selected frits and the three SB5 composition projections with variation applied to each sludge component. The Variation Stage results showed that the operating windows were reduced in width, as expected when variation in the sludge composition is applied. However, several of the down-selected frits exhibited a relatively high degree of robustness to the applied sludge variation, providing WL windows of approximately 30 to 39 wt%. The

Physical and chemical factors affecting sludge consolidation

Energy Technology Data Exchange (ETDEWEB)

Turner, C.W.; Blimkie, M.E.; Lavoie, P.A

1997-09-01

Chemical reactions between sludge components and precipitation reactions within the pores of the existing sludge are shown to contribute to the consolidation of sludge under steam generator operating conditions. Simulations of sludge representative of plants with a mixed iron/copper feedtrain suggest that as the conditions in the feedtrain become more oxidizing the sludge will become harder with a higher nickel ferrite content. The precipitation of feedwater impurities introduced by condenser leaks and of zinc silicate, which is produced in plants with brass condenser tubes and silica in the makeup water, contribute significantly to sludge consolidation. Sodium phosphate is also shown to be an agent of sludge consolidation. (author)

Research for waste water treatment technology with low production of excessive active sludge

Directory of Open Access Journals (Sweden)

Makisha Nikolay

2017-01-01

Full Text Available The article reflects the possibility to create a technological scheme of waste water treatment of domestic and similar type of sewage within minimal amount of excessive active sludge by means of bioreactors with immobilized feed. There are various aspects to be considered: technical, economic, social and ecological. According to the above it is strongly needed to provide a combination of proper waste water treatment, minimal sludge formation and the possibility for a further use of the sludge. One of the ways to achieve the goal above is to use an immobilized feed in the aeration tank. The necessary experiments were carried out in the department of waste water treatment and water ecology. The article includes the scheme of the facility and other parameters of the experiments, which has been carried. The combination of aerobic and anaerobic processes helps to provide proper quality of integrated biological treatment. Chambers of the aeration reactor were also equipped with the polymer feed of various structures. The sludge treatment that was also strongly needed was made by means of aerobic stabilization with the use of ejecting aeration. The results of experiment showed a good effect in both components – sewage and sludge treatment. Afterwards there was also an industrial model launched which confirmed the results of the previous stage.

Magnetic susceptibility and magnetic resonance measurements of the moisture content and hydration condition of a magnetic mixture material

International Nuclear Information System (INIS)

Tsukada, K.; Kusaka, T.; Saari, M. M.; Takagi, R.; Sakai, K.; Kiwa, T.; Bito, Y.

2014-01-01

We developed a magnetic measurement method to measure the moisture content and hydration condition of mortar as a magnetic mixture material. Mortar is a mixture of Portland cement, sand, and water, and these materials exhibit different magnetic properties. The magnetization–magnetic field curves of these components and of mortars with different moisture contents were measured, using a specially developed high-temperature-superconductor superconducting quantum interference device. Using the differences in magnetic characteristics, the moisture content of mortar was measured at the ferromagnetic saturation region over 250 mT. A correlation between magnetic susceptibility and moisture content was successfully established. After Portland cement and water are mixed, hydration begins. At the early stage of the hydration/gel, magnetization strength increased over time. To investigate the magnetization change, we measured the distribution between bound and free water in the mortar in the early stage by magnetic resonance imaging (MRI). The MRI results suggest that the amount of free water in mortar correlates with the change in magnetic susceptibility

Co-combustion of sewage sludge; Mitverbrennung von Klaerschlamm

Energy Technology Data Exchange (ETDEWEB)

Thome-Kozmiensky, K.J. [Technische Univ. Berlin (Germany). Fachgebiet Abfallwirtschaft

1998-09-01

Thermal sewage disposal pursues the following aims: destruction of organic pollutants contained in the sludge; concentration and removal or almost complete fixation of inorganic pollutants in the residue matrix; minimisation of the mass solid residue; production of useful products; utilisation of the caloric content. The thermal treatment chain should be as short as possible; intermediate stages in separate reactors such as digestion, drying, degasification or gasification should be avoided if the material is ultimately to be combusted. The present paper examines and assesses the co-combustion of sewage sludge. [Deutsch] Mit der thermischen Klaerschlammentsorgung werden folgende Ziele verfolgt: - Zerstoerung der im Schlamm enthaltenen organischen Schadstoffe, - Konzentration und Ausschleusung oder weitestgehende Fixierung der anorganischen Schadstoffe in die Reststoffmatrix, - Minimierung der Masse an festen Restabfaellen, - Herstellung verwertbarer Produkte, - Nutzung des Waermeeinhalts. Die thermische Behandlungskette sollte moeglichst kurz sein; Zwischenschritte wie Faulung, Trocknung, Ent- oder Vergasung in getrennten Reaktoren sollten vermieden werden, wenn letztendlich doch verbrannt wird. Das Verfahren der Mitverbrennung von Klaerschlamm wird hier untersucht und bewertet. (orig./SR)

Characteristics of Laminar Flow in Pipelines of Homogenous Alum Sludge Approximated with use of the Vočadlo Model for Viscoplastic Liquids

Directory of Open Access Journals (Sweden)

Kempiński Jan

2014-12-01

Full Text Available The study presents the manners of determination of the Darcy friction factor λ for a homogenous hydromixture of alum sludge of varied hydration and temperature for the laminar flow zone. The rheological evaluation of the hydromixture as a viscoplastic body has been conducted with use of measurements of viscosity. The curves of flow were approximated with use of the generalized Vočadlo model. The Darcy friction factor λ of the pipeline was determined with use of the non-dimensional criterion λ(Regen and λ(Re, He.

Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB Digester system

NARCIS (Netherlands)

Mahmoud, N.A.; Zeeman, G.; Gijzen, H.J.; Lettinga, G.

2004-01-01

The treatment of sewage at 15°C was investigated in a one-stage upflow anaerobic sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and sludge stabilisation. The UASB reactor was operated at a

The rates measurement of methane hydrate formation and dissociation using micro-drilling system application for gas hydrate exploration

Energy Technology Data Exchange (ETDEWEB)

Bin Dou [Engineering Faculty, China Univ. of Geosciences, Wuhan (China)]|[Inst. of Petroleum Engineering, Technology Univ. of Clausthal (Germany); Reinicke, K.M. [Inst. of Petroleum Engineering, Technology Univ. of Clausthal (Germany); Guosheng Jiang; Xiang Wu; Fulong Ning [Engineering Faculty, China Univ. of Geosciences, Wuhan (China)

2006-07-01

When drilling through gas hydrate bearing formations, the energy supplied by virtue of the drilling process may lead to a destabilization of the hydrates surrounding the wellbore. Therefore, as the number of oil and gas fields being development in deepwater and onshore arctic environments increases, greater emphasis should be placed on quantifying the risks, gas hydrates pose to drilling operations. The qualification of these risks requires a comprehensive understanding of gas hydrate-formation and dissociation as a result of drilling induced processes. To develop the required understanding of gas hydrat formation and dissociation, the authors conducted laboratory experiments by using a micro-drilling system, to study the dissociation rates of methane hydrates contained in a tank reactor. The test facility used is a development of China University of Geosciences. The rates of methane hydrate formation and dissociation in the tank reactor were measured at steady-state conditions at pressures ranging from 0.1 to 25 MPa and temperatures ranging from -5 to 20 C. The experimental results show that the rate of hydrate formation is strongly influenced by the fluid system used to form the hydrates, pressure and temperature, with the influence of the temperature on methane hydrate dissociation being stronger than that of the pressure. Drilling speed, drilling fluids and hydrate dissociation inhibitors were also shown to influence hydrate dissociation rate. The derived results have been used to predict hydrate drilling stability for several drilling fluid systems.

A Novel Method of Biological Start-up in Arak Activated Sludge Wastewater Treatment Plant

Directory of Open Access Journals (Sweden)

Abdolreza Khalili

2015-01-01

Full Text Available Startup is one of the most important stages in the operation of a wastewater treatment plant (WWTP. In this paper, a novel method is presented for the startup of Arak Activated Sludge WWTP, which is shown to contain more advantages than other common methods. In this method, a portion of the inflow is initially allowed to enter gradually into an aeration basin prior to seeding. Under these conditions, less seeding is required due to the low flow of the influent and the low volume of the aeration basin. Once MLSS in the basin reaches the desired level, the rest of the system comes into operation and the sludge developed in the system is used for further seeding. In the case of the WWPT in Arak, it took about 2 months for the total MLSS to be developed and wasting the sludge to start because of the cold weather conditions in the region. The wasted sludge was controlled by the F/M ratio at a constant sludge age. During the start-up, the MLSS increase exhibited a linear trend and the low loading allowed for the variation in influent contaminants to be controlled. The effluent contaminants were below the standard levels recommended by the Environment Protection Organization. BOD5 and COD removals increased from 40% and 60% to 90% and TSS removal increased from 70% to 96%. Lower loading levels, better process control, and lower sludge processing costs are the benefits of this system

Thermal conductivity of hydrate-bearing sediments

Science.gov (United States)

Cortes, Douglas D.; Martin, Ana I.; Yun, Tae Sup; Francisca, Franco M.; Santamarina, J. Carlos; Ruppel, Carolyn D.

2009-01-01

A thorough understanding of the thermal conductivity of hydrate-bearing sediments is necessary for evaluating phase transformation processes that would accompany energy production from gas hydrate deposits and for estimating regional heat flow based on the observed depth to the base of the gas hydrate stability zone. The coexistence of multiple phases (gas hydrate, liquid and gas pore fill, and solid sediment grains) and their complex spatial arrangement hinder the a priori prediction of the thermal conductivity of hydrate-bearing sediments. Previous studies have been unable to capture the full parameter space covered by variations in grain size, specific surface, degree of saturation, nature of pore filling material, and effective stress for hydrate-bearing samples. Here we report on systematic measurements of the thermal conductivity of air dry, water- and tetrohydrofuran (THF)-saturated, and THF hydrate–saturated sand and clay samples at vertical effective stress of 0.05 to 1 MPa (corresponding to depths as great as 100 m below seafloor). Results reveal that the bulk thermal conductivity of the samples in every case reflects a complex interplay among particle size, effective stress, porosity, and fluid-versus-hydrate filled pore spaces. The thermal conductivity of THF hydrate–bearing soils increases upon hydrate formation although the thermal conductivities of THF solution and THF hydrate are almost the same. Several mechanisms can contribute to this effect including cryogenic suction during hydrate crystal growth and the ensuing porosity reduction in the surrounding sediment, increased mean effective stress due to hydrate formation under zero lateral strain conditions, and decreased interface thermal impedance as grain-liquid interfaces are transformed into grain-hydrate interfaces.

Bacterial regrowth potential in alkaline sludges from open-sun and covered sludge drying beds

Energy Technology Data Exchange (ETDEWEB)

Alkan, U.; Topac, F.O.; Birden, B.; Baskaya, H.S. [Uludag University, Gorukle (Turkey). Dept. of Environmnetal Engineering

2007-10-15

The aim of this study was to compare the regrowth potentials of wastewater sludges dried in two pilot-scale drying processes namely, Open-Sun Sludge Drying Bed (OSDB) and Covered Sludge Drying Bed (CSDB). Quicklime and/or coal fly ash were added to raw sludge samples prior to drying processes in order to enhance bacterial inactivation. Following three drying cycles (March-April, June-July and August-October), sludge samples were taken from the beds for the regrowth experiments. Addition of alkaline materials prevented the regrowth of faecal coliforms in all rewetted samples except for the samples obtained after the rainfall events in OSDB. Rewetting of these samples in the regrowth experiments increased faecal coliform numbers by 3.5-7 log units. In contradiction, the observed bacterial numbers in rewetted alkaline samples from CSDB were below the EPA Class B criterion (2 million MPN g{center_dot} 1) dry sludge). The combination of additional heat from solar collectors, protection from the rain and the unfavourable living conditions owing to alkaline materials appeared to inactivate bacteria more effectively in CSDB and hence eliminated regrowth potential more efficiently.

Comparative Study on the Leaching Characteristics of Industrial Sludge and Fly Ash using KSLP and TCLP Techniques

International Nuclear Information System (INIS)

Lee, B.K.; Hwang, H.W.

2010-01-01

Leaching characteristics of industrial sludge and fly ash using Korean Standard Leaching Procedure (KSLP) and Toxicity Characteristics Leaching Procedure (TCLP) were studied. Possibilities of re-adsorption of heavy metal ions on the surface of sludge and ash during the course of leaching were also investigated. KSLP looked relatively more aggressive than the TCLP in leaching heavy metal ions. Concentrations of metal ions leached in both the methods, however, were found very low in comparison to the concentration of ions present in the original samples. In case of sludge, heavy metal ions showed relatively high rate of leaching at fourth and fifth stages of sequential extraction while ash showed high rate of leaching at the first three stages of extraction. Some of the concentrations of heavy metal ions leached out in the tests also found to be adsorbed on the surface of sludge and ash. Heavy metal ions present in high concentrations in the sample showed lower rate of adsorption than their leaching rate. No distinct difference in the results of KSLP and TCLP was observed. However, variations in the leaching results could be due to the different nature of hazardous waste and leaching conditions. More information like kinetics of leaching, mineralogical characteristics of waste and site characteristics of landfill were required to predict more accurate leaching behavior of ions in natural conditions. (author)

Experimental investigation of methane release from hydrate formation in sandstone through both hydrate dissociation and CO{sub 2} sequestration

Energy Technology Data Exchange (ETDEWEB)

Husebo, J.; Graue, A.; Kvamme, B. [Bergen Univ., Bergen (Norway). Dept. of Physics and Technology; Stevens, J.; Howard, J.J. [ConocoPhillips, Ponca City, OK (United States); Baldwin, B.A. [Green Country Petrophysics LLC, Dewey, OK (United States)

2008-07-01

Large amounts of natural gas trapped in hydrate reservoirs are found in Arctic regions and in deep offshore locations around the world. Natural gas production from hydrate deposits offer significant potential for future energy needs. However, research is needed in order to propose potential production schemes for natural gas hydrates. Natural gas molecules can be freed from hydrate structured cages by depressurization, by heating and by exposing the hydrate to a substance that will form a thermodynamically more stable hydrate structure. This paper provided a comparison of two approaches for releasing methane from methane hydrate in porous sandstone. The study scope covered the dissociation rate of methane hydrate in porous media through depressurization, and also referred to previous work done on producing methane from hydrates in sandstone while sequestering carbon dioxide (CO{sub 2}). The study was conducted in a laboratory setting. The paper discussed the experimental design which included the placing of a pressure- and temperature-controlled sample holder inside the bore of a magnetic resonance imager. The experimental procedures were then outlined, with reference to hydrate formation; carbon dioxide sequestration; hydrate dissociation experiments with constant volume; and hydrate dissociation experiments at constant pressure. The constant volume experiments demonstrated that in order to dissociate a large amount of hydrate, the initial depressurization had to be significantly lower than the hydrate stability pressure. 9 refs., 9 figs.

Microstructure of natural hydrate host sediments

International Nuclear Information System (INIS)

Jones, K.W.; Kerkar, P.B.; Mahajan, D.; Lindquist, W.B.; Feng, H.

2007-01-01

There is worldwide interest in the study of natural gas hydrate because of its potential impact on world energy resources, control on seafloor stability, significance as a drilling hazard and probable impact on climate as a reservoir of a major greenhouse gas. Gas hydrates can (a) be free floating in the sediment matrix (b) contact, but do not cement, existing sediment grains, or (c) actually cement and stiffen the bulk sediment. Seismic surveys, often used to prospect for hydrates over a large area, can provide knowledge of the location of large hydrate concentrations because the hydrates within the sediment pores modify seismic properties. The ability to image a sample at the grain scale and to determine the porosity, permeability and seismic profile is of great interest since these parameters can help in determining the location of hydrates with certainty. We report here on an investigation of the structure of methane hydrate sediments at the grain-size scale using the synchrotron radiation-based computed microtomography (CMT) technique. Work has started on the measurements of the changes occurring as tetrahydrofuran hydrate, a surrogate for methane hydrate, is formed in the sediment

Sludge Washing and Demonstration of the DWPF Nitric/Formic Flowsheet in the SRNL Shielded Cells for Sludge Batch 9 Qualification

Energy Technology Data Exchange (ETDEWEB)

Pareizs, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Newell, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martino, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Johnson, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-11-01

Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) to qualify the next batch of sludge – Sludge Batch 9 (SB9). Current practice is to prepare sludge batches in Tank 51 by transferring sludge to Tank 51 from other tanks. The sludge is washed and transferred to Tank 40, the current Defense Waste Process Facility (DWPF) feed tank. Prior to sludge transfer from Tank 51 to Tank 40, the Tank 51 sludge must be qualified. SRNL qualifies the sludge in multiple steps. First, a Tank 51 sample is received, then characterized, washed, and again characterized. SRNL then demonstrates the DWPF Chemical Process Cell (CPC) flowsheet with the sludge. The final step of qualification involves chemical durability measurements of glass fabricated in the DWPF CPC demonstrations. In past sludge batches, SRNL had completed the DWPF demonstration with Tank 51 sludge. For SB9, SRNL has been requested to process a blend of Tank 51 and Tank 40 at a targeted ratio of 44% Tank 51 and 56% Tank 40 on an insoluble solids basis.

From municipal/industrial wastewater sludge and FOG to fertilizer: A proposal for economic sustainable sludge management.

Science.gov (United States)

Bratina, Božidar; Šorgo, Andrej; Kramberger, Janez; Ajdnik, Urban; Zemljič, Lidija Fras; Ekart, Janez; Šafarič, Riko

2016-12-01

After a ban on the depositing of untreated sludge in landfills, the sludge from municipal and industrial water-treatment plants can be regarded as a problem. Waste products of the water treatment process can be a problem or an opportunity - a source for obtaining raw materials. In the European Union, raw sludge and fats, oil and grease (FOG) from municipal and industrial wastewater treatment plants (WWTP) cannot be deposited in any natural or controlled environment. For this reason, it must be processed (stabilized, dried) to be used later as a fertilizer, building material, or alternative fuel source suitable for co-incineration in high temperature furnaces (power plants or concrete plants). The processes of drying sludge, where heat and electricity are used, are energy consuming and economically unattractive. Beside energy efficiency, the main problem of sludge drying is in its variability of quality as a raw material. In addition to this, sludge can be contaminated by a number of organic and inorganic pollutants and organisms. Due to the presence or absence of pollutants, different end products can be economically interesting. For example, if the dried sludge contains coliform bacteria, viruses, helminths eggs or smaller quantities of heavy metals, it cannot be used as a fertilizer but can still be used as a fuel. The objectives of the current article is to present a batch-processing pilot device of sludge or digestate that allows the following: (1) low pressure and low temperature energy effective drying of from 10 to 40% remaining water content, (2) disinfection of pathogen (micro)organisms, (3) heavy metal reduction, (4) production of products of predetermined quality (e.g. containing different quantities of water; it can be used as a fertilizer, or if the percentage of water in the dry sludge is decreased to 10%, then the dried sludge can be used as a fuel with a calorific value similar to coal). An important feature is also the utilization of low

Observed gas hydrate morphologies in marine sediment

Energy Technology Data Exchange (ETDEWEB)

Holland, M.; Schultheiss, P.; Roberts, J.; Druce, M. [Geotek Ltd., Daventry, Northamptonshire (United Kingdom)

2008-07-01

The morphology of gas hydrate in marine sediments determines the basic physical properties of the sediment-hydrate matrix and provides information regarding the formation of gas hydrate deposits, and the nature of the disruption that will occur on dissociation. Small-scale morphology is useful in estimating the concentrations of gas hydrate from geophysical data. It is also important for predicting their response to climate change or commercial production. Many remote techniques for gas hydrate detection and quantification depend on hydrate morphology. In this study, morphology of gas hydrate was examined in HYACINTH pressure cores from recent seagoing expeditions. Visual and infrared observations from non-pressurized cores were also used. The expeditions and pressure core analysis were described in detail. This paper described the difference between two types of gas hydrate morphologies, notably pore-filling and grain-displacing. Last, the paper addressed the impact of hydrate morphology. It was concluded that a detailed morphology of gas hydrate is an essential component for a full understanding of the past, present, and future of any gas hydrate environment. 14 refs., 4 figs.

Changes in the ammonia-oxidizing bacteria community in response to operational parameters during the treatment of anaerobic sludge digester supernatant.

Science.gov (United States)

Cydzik-Kwiatkowska, Agnieszka; Zielińska, Magdalena; Bernat, Katarzyna; Kulikowska, Dorota; Wojnowska-Baryła, Irena

2012-07-01

The understanding of the relationship between ammoniaoxidizing bacteria (AOB) communities in activated sludge and the operational treatment parameters supports the control of the treatment of ammonia-rich wastewater. The modifications of treatment parameters by alteration of the number and length of aerobic and anaerobic stages in the sequencing batch reactor (SBR) working cycle may influence the efficiency of ammonium oxidation and induce changes in the AOB community. Therefore, in the research, the impact of an SBR cycle mode with alternating aeration/ mixing conditions (7 h/1 h vs. 4 h/5.5 h) and volumetric exchange rate (n) on AOB abundance and diversity in activated sludge during the treatment of anaerobic sludge digester supernatant at limited oxygen concentration in the aeration stage (0.7 mg O2/l) was assessed. AOB diversity expressed by the Shannon-Wiener index (H') was determined by the cycle mode. At aeration/mixing stage lengths of 7 h/1 h, H' averaged 2.48 +/- 0.17, while at 4 h/ 5.5 h it was 2.35 +/- 0.16. At the given mode, AOB diversity decreased with increasing n. The cycle mode did not affect AOB abundance; however, a higher AOB abundance in activated sludge was promoted by decreasing the volumetric exchange rate. The sequences clustering with Nitrosospira sp. NpAV revealed the uniqueness of the AOB community and the simultaneously lower ability of adaptation of Nitrosospira sp. to the operational parameters applied in comparison with Nitrosomonas sp.

Sludge Batch 7B Qualification Activities With SRS Tank Farm Sludge

International Nuclear Information System (INIS)

Pareizs, J.; Click, D.; Lambert, D.; Reboul, S.

2011-01-01

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry - Sludge Batch 7b (SB7b) - be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from H Canyon are often added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL typically simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). With the tight schedule constraints for SB7b and the potential need for caustic addition to allow for an acceptable glass processing window, the qualification for SB7b was approached differently than past batches. For SB7b, SRNL prepared a Tank 51 and a Tank 40 sample for qualification. SRNL did not receive the qualification sample from Tank 51 nor did it simulate all of the Tank Farm washing and decanting operations. Instead, SRNL prepared a Tank 51 SB7b sample from samples of Tank 7 and Tank 51, along with a wash solution to adjust the supernatant composition to the final SB7b Tank 51 Tank Farm projections. SRNL then prepared a sample to represent SB7b in Tank 40 by combining portions of the SRNL-prepared Tank 51 SB7b sample and a Tank 40 Sludge Batch 7a (SB7a) sample. The blended sample was 71% Tank 40 (SB7a) and 29% Tank 7/Tank 51 on an insoluble solids basis. This sample is referred to as the SB7b Qualification Sample. The blend represented the highest projected Tank 40 heel (as of May 25, 2011), and thus, the highest

Environmental sustainability of wastewater sludge treatments

DEFF Research Database (Denmark)

Boyer-Souchet, Florence; Larsen, Henrik Fred

treatment for municipal waste water. A special focus area in Neptune is sludge handling because the sludge amount is expected to increase due to advanced waste water treatment. The main sludge processing methods assessed in Neptune can be divided into two categories: disintegration processes before...... anaerobic digestion (thermal hydrolysis and ultrasound disintegration) and inertisation processes performed at high temperatures (incineration, pyrolysis, gasification, wet oxidation) but they all aim at volume reduction and removal of biodegradable compounds before safe sludge disposal or reuse of its...... resources. As part of a sustainability assessment (or “best practice evaluation”), a comparison between the existing and new sludge handling techniques have been done by use of life cycle assessment (LCA).The concept of induced impacts as compared to avoided impacts when introducing a new sludge treatment...

Gas hydrates forming and decomposition conditions analysis

Directory of Open Access Journals (Sweden)

А. М. Павленко

2017-07-01

Full Text Available The concept of gas hydrates has been defined; their brief description has been given; factors that affect the formation and decomposition of the hydrates have been reported; their distribution, structure and thermodynamic conditions determining the gas hydrates formation disposition in gas pipelines have been considered. Advantages and disadvantages of the known methods for removing gas hydrate plugs in the pipeline have been analyzed, the necessity of their further studies has been proved. In addition to the negative impact on the process of gas extraction, the hydrates properties make it possible to outline the following possible fields of their industrial use: obtaining ultrahigh pressures in confined spaces at the hydrate decomposition; separating hydrocarbon mixtures by successive transfer of individual components through the hydrate given the mode; obtaining cold due to heat absorption at the hydrate decomposition; elimination of the open gas fountain by means of hydrate plugs in the bore hole of the gushing gasser; seawater desalination, based on the hydrate ability to only bind water molecules into the solid state; wastewater purification; gas storage in the hydrate state; dispersion of high temperature fog and clouds by means of hydrates; water-hydrates emulsion injection into the productive strata to raise the oil recovery factor; obtaining cold in the gas processing to cool the gas, etc.

Chromium fractionation and plant availability in tannery-sludge amended soil

Science.gov (United States)

Allué, Josep; Moya Garcés, Alba; Bech, Jaume; Barceló, Juan; Poschenrieder, Charlotte

2013-04-01

soils with the highest sludge dose (20 g kg-1). Soils from the different treatments were potted (5 L) and planted with Trigonella foenum graecum seeds (1 plant per pot). Plants were harvested in the vegetative stage and processed for tissue analysis of Cr, Fe, Zn and Pb. A sequential extraction procedure was applied to the soil for getting insight into the operationally defined soil fractions that incorporate the tannery sludge derived Cr. In any of the treatments Cr was detectable in the exchangeable and easily reducible fractions. In control soils around 10% of soil Cr was in the moderately reducible fraction and the rest in the residual fraction. Contrastingly tannery sludge amended soils incorporated most Cr in the moderately reducible fraction extracted by acid oxalate. This distribution in relation to plant Cr concentrations will be discussed. Acknowledgement: Supported by the Spanish Government (project BFU2010-14873)

HYDRATE CORE DRILLING TESTS

Energy Technology Data Exchange (ETDEWEB)

John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

2002-11-01

The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate

Activated Sludge Rheology

DEFF Research Database (Denmark)

Ratkovich, Nicolas Rios; Horn, Willi; Helmus, Frank

2013-01-01

Rheological behaviour is an important fluid property that severely impacts its flow behaviour and many aspects related to this. In the case of activated sludge, the apparent viscosity has an influence on e.g. pumping, hydrodynamics, mass transfer rates, sludge-water separation (settling and filtr...... rheological measurements. Moreover, the rheological models are not very trustworthy and remain very “black box”. More insight in the physical background needs 30 to be gained. A model-based approach with dedicated experimental data collection is the key to address this.......Rheological behaviour is an important fluid property that severely impacts its flow behaviour and many aspects related to this. In the case of activated sludge, the apparent viscosity has an influence on e.g. pumping, hydrodynamics, mass transfer rates, sludge-water separation (settling......, leading to varying results and conclusions. In this paper, a vast amount of papers are critically reviewed with respect to this and important flaws are highlighted with respect to rheometer choice, rheometer settings and measurement protocol. The obtained rheograms from experimental efforts have...

Ultrasonic sludge disintegration for enhanced methane production in anaerobic digestion: effects of sludge hydrolysis efficiency and hydraulic retention time.

Science.gov (United States)

Kim, Dong-Jin; Lee, Jonghak

2012-01-01

Hydrolysis of waste activated sludge (WAS) has been regarded as the rate limiting step of anaerobic sludge digestion. Therefore, in this study, the effect of ultrasound and hydraulic residence time during sludge hydrolysis was investigated with the goal of enhancing methane production from anaerobic digestion (AD). WAS was ultrasonically disintegrated for hydrolysis, and it was semi-continuously fed to an anaerobic digesters at various hydraulic retention times (HRTs). The results of these experiments showed that the solids and chemical oxygen demand (COD) removal efficiencies when using ultrasonically disintegrated sludge were higher during AD than the control sludge. The longer the HRT, the higher the removal efficiencies of solids and COD, while methane production increased with lower HRT. Sludge with 30% hydrolysis produced 7 × more methane production than the control sludge. The highest methane yields were 0.350 m(3)/kg volatile solids (VS)(add) and 0.301 m(3)/kg COD(con) for 16 and 30% hydrolyzed sludge, respectively. In addition, we found that excess ultrasound irradiation may inhibit AD since the 50% hydrolyzed sludge produced lower methane yields than 16 and 30% hydrolyzed sludge.

Radioactive contamination of sewage sludge

International Nuclear Information System (INIS)

Soeder, C.J.; Zanders, E.; Raphael, T.

1986-01-01

Because of the radioactivity released through the explosion of the nuclear reactor near Chernobyl radionuclides have been accumulated to a significant extent in sewage sludge in the Federal Republic of Germany. This is demonstrated for samples from four activated sludge plants according to a recent recommendation of the German Commission for Radiation Protection, there is until now no reason to deviate from the common practices of sludge disposal or incineration. The degree of radioactive contamination of plant materials produced on farm lands on which sewage sludge is being spread cannot be estimated with sufficient certainty yet. Additional information is required. (orig.) [de

Sewage sludge disposal in Austria

International Nuclear Information System (INIS)

Koch, F.

1997-01-01

Sewage systems serve about 70% of the Austrian population, producing 6 million m 3 of sewage sludge per year with a dry matter content of 4-5%. At present about 52% of this sludge is disposed of in land fills, 33% is incinerated, and only about 15 % is used in agriculture. Although agricultural utilization is becoming increasingly important, several problems, especially those related to public opinion, need to be resolved before increased use will be possible. In this paper, wastewater treatment and sewage-sludge production in Austria, and problems associated with sludge disposal are discussed. (author)

Sewage sludges disinfection

International Nuclear Information System (INIS)

Alexandre, D.

1977-01-01

There is an hygienic risk in using biological sewage sludges for agriculture. Systematic analysis carried out on sludges samples obtained from purification plants in East and South part of France, show the almost uniform presence of pathogenic microorganisms. Some of it survive more than 9 months after soil application. Conventional process for disinfection: liming and heat are not suitable for agricultural use. On the other hand, irradiation involves no modification in structure and composition of sludges. Radiation doses required for disinfection vary according to microorganisms. If some of them are eliminated with rather light doses (200 krad) mycobacteria, viruses and eggs of worms resist to more important doses. Security dose is estimated around 1000 krad

40 CFR Appendix A to Part 503 - Procedure To Determine the Annual Whole Sludge Application Rate for a Sewage Sludge

Science.gov (United States)

2010-07-01

... Whole Sludge Application Rate for a Sewage Sludge A Appendix A to Part 503 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SEWAGE SLUDGE STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE Pt... a Sewage Sludge Section 503.13(a)(4)(ii) requires that the product of the concentration for each...

A high yield process for hydrate formation

Energy Technology Data Exchange (ETDEWEB)

Giavarini, C.; Maccioni, F. [Univ. of Roma La Sapienza, Roma (Italy). Dept. of Chemical Engineering

2008-07-01

Due to the large quantities of natural gas stored in deep ocean hydrates, hydrate reservoirs are a substantial energy resource. Hydrates concentrate methane by as much as a factor of 164. As such, several natural gas transportation and storage systems using gas hydrates have been studied, and many of them are nearing practical use. In these systems, the hydrate is produced as a slurry by a spray process at approximately 7 megapascal (MPa), and then shaped into pellets. The use of a spray process, instead of a conventional stirred vessel is necessary in order to reach high hydrate concentrations in the hydrate-ice system. This paper presented a new procedure to produce a bulk of concentrated methane hydrate in a static traditional reactor at moderate pressure, controlling pressure and temperature in the interval between ice melting and the hydrate equilibrium curve. This paper discussed the experimental procedure which included formation of methane hydrate at approximately 5 MPa and 2 degrees Celsius in a reaction calorimeter at a volume of two liters. Results were also discussed. It was concluded that the procedure seemed suitable for the development of a gas hydrate storage and transport technology. It was found that the spray procedure took more time, but could be sped up and made continuous by using two vessels, one for hydrate formation and the other for hydrate concentration. The advantage was the production of a concentrated hydrate, using a simpler equipment and working at lower pressures respect to the spray process. 9 refs., 5 figs.

Elementary analysis and energetic potential of the municipal sewage sludges from the Gdańsk and Kościerzyna WWTPs

Science.gov (United States)

Ostojski, Arkadiusz

2018-01-01

This paper aims to present municipal sewage sludge (MSS) elementary analysis and energetic potential based on measurement of heat of combustion (higher heating value HHV) and calculation of calorific values (lower heating value LHV). The analysis takes into the consideration water content in sewage sludge, at different utilization stages, in wastewater treatment plants in Gdańsk Wschód and Kościerzyna - Pomeranian Voivodeship. The study yielded the following results (in % dry matter): ash 19÷31 %, C - 31÷36 %, H - 5÷6 %, N - 4÷6 %, O - 28÷32 %, S - 1 %. Calorific value of stabilized sludges in Gdańsk was on average 13.8÷15 MJ/kg. In case of sludges not undergoing digestion from Kościerzyna WWTP, the calorific value was at the level of 17.5 MJ/kg. Thus, sewage sludges are good energy carriers. High water content though is the problem, as it lowers the useful effect of heat. There is no alternative for thermal sewage sludge neutralization, which is in conformity with valid Polish National Waste Management Plan (KPGO 2022).

PBDEs in Italian sewage sludge and environmental risk of using sewage sludge for land application

International Nuclear Information System (INIS)

Cincinelli, Alessandra; Martellini, Tania; Misuri, Lorenza; Lanciotti, Eudes; Sweetman, Andy; Laschi, Serena; Palchetti, Ilaria

2012-01-01

Polybrominated diphenyl ethers (PBDEs) were determined in sewage sludge samples collected from eight Italian wastewater treatment plants (WWTPs) between June 2009 and March 2010. Total PBDE concentrations ranged from 158.3 to 9427 ng g −1 dw, while deca-BDE (BDE-209) (concentrations ranging from 130.6 to 9411 ng g −1 dw) dominated the congener profile in all the samples, contributing between 77% and 99.8% of total PBDE. The suitability of using a magnetic particle enzyme-linked immunoassay (ELISA) to analyse PBDEs in sewage sludge was also tested. The ELISA results, expressed as BDE-47 equivalents, were well correlated with those obtained by GC–NCI–MS, with correlation coefficients (r 2 ) of 0.899 and 0.959, depending on the extraction procedure adopted. The risk assessment of PBDEs in sewage sludge addressed to land application was calculated. PEC soil values compared to the relative PNEC soil for penta and deca-BDE suggests that there is a low risk to the soil environment. - Highlights: ► PBDEs in sewage sludge were determined in eight Italian WWTPs for the first time. ► PBDEs concentrations showed differences between the eight investigated WWTPs. ► Deca-BDE (BDE-209) was the dominant congener in all samples. ► The suitability of using ELISA method to analyse PBDEs in sewage sludge was tested. ► The risk assessment of using sewage sludge for land application was evaluated. - Determination of PBDEs in sewage sludge by GC–NCI–MS and ELISA test and risk assessment when sewage sludge is used for land application.

Agricultural yields of irradiated sewage sludge

International Nuclear Information System (INIS)

Magnavacca, Cecilia; Miranda, E.; Sanchez, M.

1999-01-01

Lettuce, radish and ryegrass have been used to study the nitrogen fertilization of soil by sewage sludge. The results show that the irradiated sludge improve by 15 - 30 % the production yield, compared to the non-irradiated sludge. (author)

Sustainability of Domestic Sewage Sludge Disposal

Directory of Open Access Journals (Sweden)

Claudia Bruna Rizzardini

2014-04-01

Full Text Available Activated sludge is now one of the most widely used biological processes for the treatment of wastewaters from medium to large populations. It produces high amounts of sewage sludge that can be managed and perceived in two main ways: as a waste it is discharged in landfill, as a fertilizer it is disposed in agriculture with direct application to soil or subjected to anaerobic digestion and composting. Other solutions, such as incineration or production of concrete, bricks and asphalt play a secondary role in terms of their degree of diffusion. The agronomical value of domestic sewage sludge is a proved question, which may be hidden by the presence of several pollutants such as heavy metals, organic compounds and pathogens. In this way, the sustainability of sewage sludge agricultural disposal requires a value judgment based on knowledge and evaluation of the level of pollution of both sewage sludge and soil. The article analyzed a typical Italian case study, a water management system of small communities, applying the criteria of evaluation of the last official document of European Union about sewage sludge land application, the “Working Document on Sludge (3rd draft, 2000”. The report brought out good sewage sludge from small wastewater treatment plants and soils quality suggesting a sustainable application.

Virological investigations on inadiated sewage sludge

International Nuclear Information System (INIS)

Epp, C.

1980-08-01

The virusinactivating activity of a Co 60 -irradiation pilot plant at Geiselbullach/Munich was to be examined. We investigated 16 impure sewage water, 15 purified sewage water, 32 raw sladge samples, 62 digested sludge samples before irradiation, 52 digested sludge samples after irradiation and 9 raw sludge samples after irradiation. We completed these investigations by adding poliovaccinevirus type 1 to the digested sludge before irradiation and by adding suspensions of pure virus in MEM + 2% FBS packed in synthetic capsules and mixtures of virus and sludge packed in synthetic capsules to the digested sludge. After the irradiation we collected the capsules and determined the virustiter. The testviruses were poliovaccinevirus type 1, poliowildvirus type 1, echovirus type 6, coxsackie-B-virus type 5, coxsackie-A-virus type 9 and adenovirus type 1. In the field trial the irradiation results were like the laboratory results assuming that the sewage sludge was homogenized enough by digestion and the solid particle concentration was not more than 3%. The D-value was 300-400 krad for enteroviruses and 700 krad for adenovirus. (orig.) [de

A review on sludge dewatering indices.

Science.gov (United States)

To, Vu Hien Phuong; Nguyen, Tien Vinh; Vigneswaran, Saravanamuth; Ngo, Huu Hao

2016-01-01

Dewatering of sludge from sewage treatment plants is proving to be a significant challenge due to the large amounts of residual sludges generated annually. In recent years, research and development have focused on improving the dewatering process in order to reduce subsequent costs of sludge management and transport. To achieve this goal, it is necessary to establish reliable indices that reflect the efficiency of sludge dewatering. However, the evaluation of sludge dewaterability is not an easy task due to the highly complex nature of sewage sludge and variations in solid-liquid separation methods. Most traditional dewatering indices fail to predict the maximum cake solids content achievable during full-scale dewatering. This paper reviews the difficulties in assessing sludge dewatering performance, and the main techniques used to evaluate dewatering performance are compared and discussed in detail. Finally, the paper suggests a new dewatering index, namely the modified centrifugal index, which is demonstrated to be an appropriate indicator for estimating the final cake solids content as well as simulating the prototype dewatering process.

Comparison and analysis of membrane fouling between flocculent sludge membrane bioreactor and granular sludge membrane bioreactor.

Directory of Open Access Journals (Sweden)

Wang Jing-Feng

Full Text Available The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs, two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates.

Modeling Aspects Of Activated Sludge Processes Part I: Process Modeling Of Activated Sludge Facilitation And Sedimentation

International Nuclear Information System (INIS)

Ibrahim, H. I.; EI-Ahwany, A.H.; Ibrahim, G.

2004-01-01

Process modeling of activated sludge flocculation and sedimentation reviews consider the activated sludge floc characteristics such as: morphology viable and non-viable cell ratio density and water content, bio flocculation and its kinetics were studied considering the characteristics of bio flocculation and explaining theory of Divalent Cation Bridging which describes the major role of cations in bio flocculation. Activated sludge flocculation process modeling was studied considering mass transfer limitations from Clifft and Andrew, 1981, Benefild and Molz 1983 passing Henze 1987, until Tyagi 1996 and G. Ibrahim et aI. 2002. Models of aggregation and breakage of flocs were studied by Spicer and Pratsinis 1996,and Biggs 2002 Size distribution of floes influences mass transfer and biomass separation in the activated sludge process. Therefore, it is of primary importance to establish the role of specific process operation factors, such as sludge loading dynamic sludge age and dissolved oxygen, on this distribution with special emphasis on the formation of primary particles

Detection and Production of Methane Hydrate

Energy Technology Data Exchange (ETDEWEB)

George Hirasaki; Walter Chapman; Gerald Dickens; Colin Zelt; Brandon Dugan; Kishore Mohanty; Priyank Jaiswal

2011-12-31

This project seeks to understand regional differences in gas hydrate systems from the perspective of as an energy resource, geohazard, and long-term climate influence. Specifically, the effort will: (1) collect data and conceptual models that targets causes of gas hydrate variance, (2) construct numerical models that explain and predict regional-scale gas hydrate differences in 2-dimensions with minimal 'free parameters', (3) simulate hydrocarbon production from various gas hydrate systems to establish promising resource characteristics, (4) perturb different gas hydrate systems to assess potential impacts of hot fluids on seafloor stability and well stability, and (5) develop geophysical approaches that enable remote quantification of gas hydrate heterogeneities so that they can be characterized with minimal costly drilling. Our integrated program takes advantage of the fact that we have a close working team comprised of experts in distinct disciplines. The expected outcomes of this project are improved exploration and production technology for production of natural gas from methane hydrates and improved safety through understanding of seafloor and well bore stability in the presence of hydrates. The scope of this project was to more fully characterize, understand, and appreciate fundamental differences in the amount and distribution of gas hydrate and how this would affect the production potential of a hydrate accumulation in the marine environment. The effort combines existing information from locations in the ocean that are dominated by low permeability sediments with small amounts of high permeability sediments, one permafrost location where extensive hydrates exist in reservoir quality rocks and other locations deemed by mutual agreement of DOE and Rice to be appropriate. The initial ocean locations were Blake Ridge, Hydrate Ridge, Peru Margin and GOM. The permafrost location was Mallik. Although the ultimate goal of the project was to understand

The Potential Socio-economic Impacts of Gas Hydrate Exploitation

Science.gov (United States)

Riley, David; Schaafsma, Marije; Marin-Moreno, Héctor; Minshull, Tim A.

2017-04-01

Gas hydrate has garnered significant interest as a possible clean fossil fuel resource, especially in countries with limited energy supplies. Whilst the sector is still in its infancy, there has been escalating development towards commercial production. To the best of our knowledge it appears that, despite its potential, existing analyses of the social and economic impacts of hydrate exploitation have been very limited. Before any viable commercial production commences, the potential impacts across society must be considered. It is likely that such impact assessments will become a legislative requirement for hydrate exploitation, similar to their requirement in conventional oil and gas projects. Social impact analysis should guide hydrate development to have the highest possible net benefits to the human and natural environment. Without active commercial hydrate operations, potential socio-economic impacts can only be inferred from other fossil fuel resource focused communities, including those directly or indirectly affected by the oil and gas industry either in the vicinity of the well or further afield. This review attempts to highlight potential impacts by synthesising current literature, focusing on social impacts at the extraction stage of operation, over time. Using a DPSIR (Driving forces; Pressures; States; Impacts; Responses) framework, we focus on impacts upon: health and wellbeing, land use and access, services and infrastructure, population, employment opportunities, income and lifestyles. Human populations directly or indirectly related with fossil fuel extraction activities often show boom and bust dynamics, and so any impacts may be finite or change temporally. Therefore potential impacts have to be reassessed throughout the lifetime of the exploitation. Our review shows there are a wide range of possible positive and negative socio-economic impacts from hydrate development. Exploitation can bring jobs and infrastructure to remote areas, although

Artificial Hydration and Nutrition

Science.gov (United States)

... Crisis Situations Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight Loss and Diet Plans ... Your Health Resources Healthcare Management Artificial Hydration and Nutrition Artificial Hydration and Nutrition Share Print Patients who ...

Alcohol cosurfactants in hydrate antiagglomeration.

Science.gov (United States)

York, J Dalton; Firoozabadi, Abbas

2008-08-28

Because of availability, as well as economical and environmental considerations, natural gas is projected to be the premium fuel of the 21st century. Natural gas production involves risk of the shut down of onshore and offshore operations because of blockage from hydrates formed from coproduced water and hydrate-forming species in natural gas. Industry practice has been usage of thermodynamic inhibitors such as alcohols often in significant amounts, which have undesirable environmental and safety impacts. Thermodynamic inhibitors affect bulk-phase properties and inhibit hydrate formation. An alternative is changing surface properties through usage of polymers and surfactants, effective at 0.5 to 3 weight % of coproduced water. One group of low dosage hydrate inhibitors (LDHI) are kinetic inhibitors, which affect nucleation rate and growth. A second group of LDHI are antiagglomerants, which prevent agglomeration of small hydrate crystallites. Despite great potential, work on hydrate antiagglomeration is very limited. This work centers on the effect of small amounts of alcohol cosurfactant in mixtures of two vastly different antiagglomerants. We use a model oil, water, and tetrahydrofuran as a hydrate-forming species. Results show that alcohol cosurfactants may help with antiagglomeration when traditional antiagglomerants alone are ineffective. Specifically, as low as 0.5 wt. % methanol cosurfactant used in this study is shown to be effective in antiagglomeration. Without the cosurfactant there will be agglomeration independent of the AA concentration. To our knowledge, this is the first report of alcohol cosurfactants in hydrate antiagglomerants. It is also shown that a rhamnolipid biosurfactant is effective down to only 0.5 wt. % in such mixtures, yet a quaternary ammonium chloride salt, i. e., quat, results in hydrate slurries down to 0.01 wt. %. However, biochemical surfactants are less toxic and biodegradable, and thus their use may prove beneficial even if at

Hydration dependent dynamics in RNA

International Nuclear Information System (INIS)

Olsen, Greg L.; Bardaro, Michael F.; Echodu, Dorothy C.; Drobny, Gary P.; Varani, Gabriele

2009-01-01

The essential role played by local and collective motions in RNA function has led to a growing interest in the characterization of RNA dynamics. Recent investigations have revealed that even relatively simple RNAs experience complex motions over multiple time scales covering the entire ms-ps motional range. In this work, we use deuterium solid-state NMR to systematically investigate motions in HIV-1 TAR RNA as a function of hydration. We probe dynamics at three uridine residues in different structural environments ranging from helical to completely unrestrained. We observe distinct and substantial changes in 2 H solid-state relaxation times and lineshapes at each site as hydration levels increase. By comparing solid-state and solution state 13 C relaxation measurements, we establish that ns-μs motions that may be indicative of collective dynamics suddenly arise in the RNA as hydration reaches a critical point coincident with the onset of bulk hydration. Beyond that point, we observe smaller changes in relaxation rates and lineshapes in these highly hydrated solid samples, compared to the dramatic activation of motion occurring at moderate hydration

Utilization of municipal sewage sludge as additives for the production of eco-cement

International Nuclear Information System (INIS)

Lin, Yiming; Zhou, Shaoqi; Li, Fuzhen; Lin, Yixiao

2012-01-01

Highlights: ► The results of X-ray diffraction (XRD) pattern and scanning electron micrograph (SEM) indicated that the major components in the eco-cement clinkers were similar to those in ordinary Portland cement. ► Though the C 2 S phase formation increased with the increase of sewage sludge contents. ► All the eco-cement pastes had a longer initial setting time and final setting time than those of plain cement paste, which increased as the sewage sludge contents in raw meal increased. ► All the eco-cement pastes had lower early flexural strengths and it increased with the increase of sewage sludge contents increased, while the compressive strengths decreased slightly. ► However, it had no significant effect on all the strengths at later ages. - Abstract: The effects of using dried sewage sludge as additive on cement property in the process of clinker burning were investigated in this paper. The eco-cement samples were prepared by adding 0.50–15.0% of dried sewage sludge to unit raw meal, and then the mixtures were burned at 1450 °C for 2 h. The results indicated that the major components in the eco-cement clinkers were similar to those in ordinary Portland cement. Although the C 2 S phase formation increased with the increase of sewage sludge content, it was also found that the microstructure of the mixture containing 15.0% sewage sludge in raw meal was significantly different and that a larger amount of pores were distributed in the clinker. Moreover, all the eco-cement pastes had a longer initial setting time and final setting time than those of plain cement paste, which increased as the sewage sludge content in the raw meal increased. All the eco-cement pastes had lower early flexural strengths, which increased as the sewage sludge content increased, while the compressive strengths decreased slightly. However, this had no significant effect on all the strengths at later stages. Furthermore, the leaching concentrations of all the types of eco

Membrane installation for enhanced up-flow anaerobic sludge blanket (UASB) performance.

Science.gov (United States)

Liu, Yin; Zhang, Kaisong; Bakke, Rune; Li, Chunming; Liu, Haining

2013-09-01

It is postulated that up-flow anaerobic sludge blanket (UASB) reactor efficiency can be enhanced by a membrane immersed in the reactor to operate it as an anaerobic membrane bioreactor (AnMBR) for low-strength wastewater treatment. This postulate was tested by comparing the performance with and without a hollow fiber microfiltration membrane module immersed in UASB reactors operated at two specific organic loading rates (SOLR). Results showed that membrane filtration enhanced process performance and stability, with over 90% total organic carbon (TOC) removal consistently achieved. More than 91% of the TOC removal was achieved by suspended biomass, while less than 6% was removed by membrane filtration and digestion in the membrane attached biofilm during stable AnMBRs operation. Although the membrane and its biofilm played an important role in initial stage of the high SOLR test, linear increased TOC removal by bulk sludge mainly accounted for the enhanced process performance, implying that membrane led to enhanced biological activity of the suspended sludge. The high retention of active fine sludge particles in suspension was the main reason for this significant improvement of performance and biological activity, which led to decreased SOLR with time to a theoretical optimal level around 2  g COD/g MLVSS·d and the establishment of a microbial community dominated by Methanothrix-like microbes. It was concluded that UASB process performance can be enhanced by transforming such to AnMBR operation when the loading rate is too high for sufficient sludge retention, and/or when the effluent water quality demands are especially stringent. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Winery wastewater treatment by heterogeneous Photo-Fenton process and activated sludges; Depuracion de efluentes vinicolas ediante tratamientos Foto-Fenton en fase heterogenea y lodos activos

Energy Technology Data Exchange (ETDEWEB)

Mosteo, R.; Lalinde, N.; Ormad, Maria O. M.; Ovelleiro, J. L.

2007-07-01

The system composed by heterogeneous Photon-Fenton assisted by solar light and biological treatment based on activated sludge process treats adequately real winery wastewaters. the previous stage based on heterogeneous Photo-Fenton process produces a partial degradation of winery wastewaters and achieves a yield of degradation of organic matter (measured as TOC) close to 50%. The activated sludge process in simple stage doesn't present any operation problems (bulking phenomenon) and achieves a yield of degradation of organic matter of 90%. (Author) 16 refs.

Investigations into surfactant/gas hydrate relationship

Energy Technology Data Exchange (ETDEWEB)

Rogers, Rudy; Zhang, Guochang; Dearman, Jennifer; Woods, Charles [Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS 39762 (United States)

2007-03-15

Gas hydrates have unique physical properties portending useful industrial applications of gas storage, gas separation, or water desalination. When gas hydrates were found in the early 1990s to occur naturally and abundantly in seafloors, three other primary interests and concerns emerged: potential new energy source, climate threat from their greenhouse gases, and seafloor instabilities. This paper presents research showing how anionic synthetic surfactants helped develop an industrial gas hydrate storage process for natural gas and how naturally-occurring in-situ anionic biosurfactants influence the formation and placement of gas hydrates in ocean sediments. The catalytic effects, mechanisms, and surface specificities imparted by synthetic surfactants in the gas storage process and imparted by biosurfactants in porous media are discussed. The Bacillus subtilis bacterium that is indigenous to gas hydrate mounds in the Gulf of Mexico was cultured in the laboratory. Its biosurfactant was separated and found to catalyze gas hydrates in porous media. The experiments indicate that seafloor-biosurfactants can be produced rapidly in-situ to achieve threshold concentrations whereby hydrates are promoted. The biosurfactants accumulate and promote hydrate formation on specific mineral surfaces such as sodium montmorillonite. (author)

Hydration of refractory cements, with spinel phase generated in-situ

International Nuclear Information System (INIS)

Lavat, A.E; Grasselli, M.C; Giuliodori Lovecchio, E

2008-01-01

High alumina refractory materials with additions of synthetic spinel (MgAl 2 O 4 ) have good thermo mechanical and attack from slag properties, which are useful in many technological applications. The spinel phase generated in-situ, MA, has proven to be a suitable and economic alternative to the use of sintered or electrocast spinels. Prior studies have established synthesis conditions for refractory cements with the spinel phase generated in-situ (CCAMA) starting with alumina mixtures and Buenos Aires dolomites. The binding properties of the aluminous cements depend on the hydrated calcium aluminates that form in the setting and hardening stages of the pastes. To avoid breaks, the refractory material must undergo programmed heating before reaching the serviceable temperature. It should also include the present phases and the transformations that occur at different temperatures. In this context knowledge about the green mineral composition and its response to an increase in temperature is especially important. This work presents studies to define the composition of CCAMA cement mortars at different hydration ages, and to estimate phase proportions and behavior during dehydration. DRX and FTIR techniques are applied in order to follow the structural changes that take place during the hydration process. The evolution of the dehydration is also studied, mostly using FTIR. The mortars were prepared with a water/cement ration of 0.5, recommended for this kind of work. The hydration was carried out at room temperature and samples were analyzed at the following ages: 15 min.; 1 h.; 1, 3, 7, 14, 28, 60 and 90 days. With the results the evolution of the phases as a function of the age of the hydration were studied. The main hydrate that was formed was CAH 10 , with a significantly increased proportion during the first 14 days of hydration. Its carbonation was also observed by the presence of calcium carboaluminates and the formation of gibbsite. The MA phase is also

Impact of sludge retention time on sludge characteristics and microbial community in MBR.

Science.gov (United States)

Su, Yuchun; Pan, Jill Ruhsing; Huang, Chihpin; Chang, Chialing

2011-01-01

In this study, the impact of sludge retention time (SRT) on sludge characteristics and microbial community and the effect on membrane fouling in membrane bioreactor (MBR) was investigated. The results show that MBR with longer SRT has less fouling propensity, in agreement with other studies, despite the fact that the MBR with longer SRT contained higher MLSS and smaller particle size. However, much more soluble microbial products (SMPs) were released in MBR with shorter SRT. More slime on the membrane surface was observed in MBR with shorter SRT while sludge cakes formed on the membrane surface in MBR with longer SRT. The results show that SMP contributes to the severe fouling observed in MBR with shorter SRT, which is in agreement with other studies showing that SMPs were the major foulants in MBR. Under different SRTs of operation, the bacterial community structures of the sludge obtained by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were almost identical, but those on the membrane surface differed substantially. It suggests that, although SRT has impact on sludge characteristics, it doesn't affect the microbial community in the suspension.

REDUCTION OF EXCESS SLUDGE PRODUCTION IN AN ACTIVATED SLUDGE SYSTEM BASED ON LYSIS-CRYPTIC GROWTH, UNCOUPLING METABOLISM AND FOLIC ACID ADDITION

Directory of Open Access Journals (Sweden)

V. F. Velho

Full Text Available Abstract The following sludge reduction alternatives were tested in wastewater biological reactors: oxic-settling-anaerobic (OSA-process; ultrasonic disintegration (UD; chlorination (CH; 3,3',4',5-tetrachlorosalicylanilide (TCS; and folic acid (FA. Compared to the control system, UD reduced 55% of the sludge production, and greater substrate and nutrient removal efficiency was achieved. CH worsened the sludge settleability and increased the SVI values; the system achieved 25% of sludge reduction. OSA showed 50% and 60% of sludge reduction after 16 and 10 hours under anaerobic conditions, respectively. The observed sludge yield during TCS addition was decreased by 40%, and the sludge settleability worsened. FA presented the highest sludge reduction (75%, and the system improved the nutrient removal efficiency by 30% compared to the control system and maintained the sludge properties. Acute toxicity conducted with Daphnia magna classified the effluent from the sludge reduction systems as non-toxic for discharge into water sources.

Accelerated hydration of high silica cements

International Nuclear Information System (INIS)

Walker, Colin; Yui, Mikazu

2012-01-01

Current Japanese designs for high level radioactive waste (HLW) repositories anticipate the use of both bentonite (buffer and backfill material) and cement based materials. Using hydrated Ordinary Portland Cement (OPC) as a grouting material is undesirable because the associated high pH buffer will have an undisputed detrimental effect on the performance of the bentonite buffer and backfill and of the host rock by changing its porosity. Instead, hydrated low pH cement (LopHC) grouting materials are being developed to provide a pH inferior or equal to 11 to reduce these detrimental effects. LopHC grouting materials use mixtures of superfine OPC (SOPC) clinker and silica fume (SF), and are referred as high silica cements (HSC). The focus of the present study was to identify the development of the unhydrated and hydrated mineral assemblage and the solution chemistry during the hydration of HSC. Since hydration experiments of cementitious materials are notably slow, a ball mill was used to accelerate hydration. This was done for two reasons. Firstly, to develop a method to rapidly hydrate cement based materials without the need for higher temperatures (which can alter the mineral assemblage), and secondly, to ensure that the end point of hydration was reached in a reasonable time frame and so to realize the final mineralogy and solution chemistry of hydrated HSC

Hexavalent chromium removal using aerobic activated sludge batch ...

African Journals Online (AJOL)

The following Cr(VI) removal systems were tested: activated sludge alone; activated sludge with an external electron donor (5 g/. of lactose); activated sludge with PAC addition (4 g/.); activated sludge with both PAC and lactose; and PAC alone. The results reported here showed that activated sludges are capable of ...

A Hydrate Database: Vital to the Technical Community

Directory of Open Access Journals (Sweden)

D Sloan

2007-06-01

Full Text Available Natural gas hydrates may contain more energy than all the combined other fossil fuels, causing hydrates to be a potentially vital aspect of both energy and climate change. This article is an overview of the motivation, history, and future of hydrate data management using a CODATA vehicle to connect international hydrate databases. The basis is an introduction to the Gas Hydrate Markup Language (GHML to connect various hydrate databases. The accompanying four articles on laboratory hydrate data by Smith et al., on field hydrate data by L?wner et al., on hydrate modeling by Wang et al., and on construction of a Chinese gas hydrate system by Xiao et al. provide details of GHML in their respective areas.

Assessing the potential of brachiaria decumbens as remediation agent for soil contaminated wit oil sludge

International Nuclear Information System (INIS)

Latiffah Norddin; Ahmad Nazrul Abd Wahid; Hazlina Abdullah; Abdul Razak Ruslan

2005-01-01

Bioremediation is a method of treatment of soil or water contaminated with toxic materials, involving the use of living organisms. Oil or petroleum sludge is a waste product of the petroleum refining industry, and is now accumulating at a fast rate at petroleum refinery sites in the country. Common components of oil sludge are mud and sand, containing toxic materials from hydrocarbons, heavy metals and radioactive elements from the seabed. In the present study, the oil sludge samples were obtained from barrels of the materials stored at the Radioactive Waste Treatment Centre, MINT. The samples were analysed of their compounds, elemental and radioactive contents. Trials on microbial degradation of the sludge materials were ongoing. This paper discusses the potential of a grass to remediate soils contaminated with petroleum sludge. Remediation of soils contaminated with organic compounds and heavy metals using plants, including grasses, including Vetiver, Lolium and Agrostis have been carried out in many countries. A greenhouse pot trial was conducted to assess the suitability of the pasture grass Brachiaria decumbens Stapf. and its mutant Brachiaria decumbens KLUANG Comel as a remediation agent for oil sludge contaminated soil. Samples of grasses and soils before planting, during growth stage and at end of experiment were analysed for the different toxicity. Although the grasses were promoted for use in pasture, and KLUANG Comel has good potential as an ornamental plant, too, their other potentials, including as phytoremediation agents need to be explored. (Author)

First-order hydrothermal oxidation kinetics of digested sludge compared with raw sludge.

Science.gov (United States)

Shanableh, A; Imteaz, M

2008-09-01

This article presents an assessment of the first-order hydrothermal oxidation kinetics of a selected digested sludge at subcritical ( 374 degrees C) temperatures in the range of 250-460 degrees C. Furthermore, the results were compared with reported oxidation kinetics of raw sludge treated under identical experimental conditions. In the assessment, oxidation was considered to proceed in two steps: (1) decomposition of the particulate, or non-filterable, chemical oxygen demand (PCOD); followed by (2) ultimate oxidation and removal of the total, particulate and soluble, COD. The accumulation and removal of soluble COD (SCOD) was determined from the difference between the rates of sludge decomposition and ultimate oxidation. Using results from batch and continuous-flow hydrothermal treatment experiments, the reacting organic ingredients were separated into groups according to the ease or difficulty at which they were decomposed or removed, with Arrhenius-type activation energy levels assigned to the different groups. The analysis confirmed that within the treatment range of 75% to more than 97% COD removal, the oxidation kinetics of the digested and raw sludges were nearly identical despite differences in the proportions of their original organic ingredients. The original organic ingredients were mostly removed above 75% COD removal, and the oxidation kinetics appeared to be dominated by the removal of acetic acid, an intermediate by-product which constituted 50% to more than 80% of the remaining COD. Furthermore, the oxidation kinetics of both sludge types were consistent with reported first-order oxidation kinetics of pure acetic acid solutions. The resulting kinetic models adequately represented hydrothermal oxidation of digested sludge, in terms of COD and PCOD removals, as well as accumulation and removal of the soluble SCOD.

Electrodialytic removal of cadmium from wastewater sludge

DEFF Research Database (Denmark)

Jakobsen, M. R.; Fritt-Rasmussen, Janne; Nielsen, S.

2004-01-01

This paper presents for the first time laboratory results demonstrating electrodialytic removal of Cd from wastewater sludge, which is a method originally developed for soil remediation. During the remediation a stirred suspension of wastewater sludge was exposed to an electric dc field. The liquid....../solid (ml/g fresh sludge) ratio was between 1.4 and 2. Three experiments were performed where the sludge was suspended in distilled water, citric acid or HNO"3. The experimental conditions were otherwise identical. The Cd removal in the three experiments was 69, 70 and 67%, respectively, thus the removal...... was approximately the same. Chemical extraction experiments with acidic solutions showed that 5-10 times more Cd could be extracted from decomposed sludge than from fresh sludge. It is likely that the mobilization of Cd during decomposition of the sludge contributes to the efficient removal of Cd...

Study of cements silicate phases hydrated under high pressure and high temperature; Etude des phases silicatees du ciment hydrate sous haute pression et haute temperature

Energy Technology Data Exchange (ETDEWEB)

Meducin, F.

2001-10-01

{alpha}-C{sub 2}SH is also produced. Compression tests are done to correlate macroscopic behavior and physico chemical properties of the products. With super-plasticizers, samples porosity is lower and the 28-day aged samples recover the Young modulus they had at the early stage of hydration. (author)

Respirometry in activated sludge

NARCIS (Netherlands)

Spanjers, H.

1993-01-01

The purpose of the study was (1) to develop a respiration meter capable of continuously measuring, using different procedures, the oxygen uptake rate of activated sludge and (2) to expand knowledge about respiration related characteristics of wastewater and activated sludge.

A

Sustainable sludge management in developing countries

Energy Technology Data Exchange (ETDEWEB)

Jimenez, B.; Barrios, J.A.; Mendez, J.M.; Diaz, J.

2003-07-01

Worldwide, unsanitary conditions are responsible of more than three million deaths annually. One of the reasons is the low level of sanitation in developing countries. Particularly, sludge from these regions has a high parasite concentration and low heavy metal content even though the available information is limited. Different issues needed to achieve a sustainable sludge management in developing nations are analysed. Based on this analysis some conclusions arise: sludge management plays an important role in sanitation programs by helping reduce health problems and associated risks; investments in sanitation should consider sludge management within the overall projects; the main restriction for reusing sludge is the high microbial concentration, which requires a science-based decision of the treatment process, while heavy metals are generally low; the adequate sludge management needs the commitment of those sectors involved in the development and enforcement of the regulations as well as those that are directly related to its generation, treatment, reuse or disposal; current regulations have followed different approaches, based mainly on local conditions, but they favour sludge reuse to fight problems like soil degradation, reduced crop production, and the increased use of inorganic fertilizers. This paper summarises an overview of theses issues. (author)

Storage capacity of hydrogen in gas hydrates

International Nuclear Information System (INIS)

Tsuda, Takaaki; Ogata, Kyohei; Hashimoto, Shunsuke; Sugahara, Takeshi; Sato, Hiroshi; Ohgaki, Kazunari

2010-01-01

The storage capacity of H 2 in the THF, THT, and furan hydrates was studied by p-V-T measurements. We confirmed that the storage and release processes of H 2 in all hydrates could be performed reversibly by pressure swing without destroying of hydrate cages. H 2 absorption in both THT and furan hydrates is much faster than THF hydrate in spite of same unit-cell structure. On the other hand, the storage amounts of H 2 are coincident in the all additive hydrates and would reach at about 1.0 mass% asymptotically.

Properties of samples containing natural gas hydrate from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, determined using Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI)

Science.gov (United States)

Winters, W.J.

1999-01-01

As part of an ongoing laboratory study, preliminary acoustic, strength, and hydraulic conductivity results are presented from a suite of tests conducted on four natural-gas-hydrate-containing samples from the Mackenzie Delta JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. The gas hydrate samples were preserved in pressure vessels during transport from the Northwest Territories to Woods Hole, Massachusetts, where multistep tests were performed using GHASTLI (Gas Hydrate And Sediment Test Laboratory Instrument), which recreates pressure and temperature conditions that are stable for gas hydrate. Properties and changes in sediment behaviour were measured before, during, and after controlled gas hydrate dissociation. Significant amounts of gas hydrate occupied the sample pores and substantially increased acoustic velocity and shear strength.

Pressurized Fluidized Bed Combustion of Sewage Sludge

Science.gov (United States)

Suzuki, Yoshizo; Nojima, Tomoyuki; Kakuta, Akihiko; Moritomi, Hiroshi

A conceptual design of an energy recovering system from sewage sludge was proposed. This system consists of a pressurized fluidized bed combustor, a gas turbine, and a heat exchanger for preheating of combustion air. Thermal efficiency was estimated roughly as 10-25%. In order to know the combustion characteristics of the sewage sludge under the elevated pressure condition, combustion tests of the dry and wet sewage sludge were carried out by using laboratory scale pressurized fluidized bed combustors. Combustibility of the sewage sludge was good enough and almost complete combustion was achieved in the combustion of the actual wet sludge. CO emission and NOx emission were marvelously low especially during the combustion of wet sewage sludge regardless of high volatile and nitrogen content of the sewage sludge. However, nitrous oxide (N2O) emission was very high. Hence, almost all nitrogen oxides were emitted as the form of N2O. From these combustion tests, we judged combustion of the sewage sludge with the pressurized fluidized bed combustor is suitable, and the conceptual design of the power generation system is available.

Well log characterization of natural gas-hydrates

Science.gov (United States)

Collett, Timothy S.; Lee, Myung W.

2012-01-01

In the last 25 years there have been significant advancements in the use of well-logging tools to acquire detailed information on the occurrence of gas hydrates in nature: whereas wireline electrical resistivity and acoustic logs were formerly used to identify gas-hydrate occurrences in wells drilled in Arctic permafrost environments, more advanced wireline and logging-while-drilling (LWD) tools are now routinely used to examine the petrophysical nature of gas-hydrate reservoirs and the distribution and concentration of gas hydrates within various complex reservoir systems. Resistivity- and acoustic-logging tools are the most widely used for estimating the gas-hydrate content (i.e., reservoir saturations) in various sediment types and geologic settings. Recent integrated sediment coring and well-log studies have confirmed that electrical-resistivity and acoustic-velocity data can yield accurate gas-hydrate saturations in sediment grain-supported (isotropic) systems such as sand reservoirs, but more advanced log-analysis models are required to characterize gas hydrate in fractured (anisotropic) reservoir systems. New well-logging tools designed to make directionally oriented acoustic and propagation-resistivity log measurements provide the data needed to analyze the acoustic and electrical anisotropic properties of both highly interbedded and fracture-dominated gas-hydrate reservoirs. Advancements in nuclear magnetic resonance (NMR) logging and wireline formation testing (WFT) also allow for the characterization of gas hydrate at the pore scale. Integrated NMR and formation testing studies from northern Canada and Alaska have yielded valuable insight into how gas hydrates are physically distributed in sediments and the occurrence and nature of pore fluids(i.e., free water along with clay- and capillary-bound water) in gas-hydrate-bearing reservoirs. Information on the distribution of gas hydrate at the pore scale has provided invaluable insight on the mechanisms

Seeking key microorganisms for enhancing methane production in anaerobic digestion of waste sewage sludge.

Science.gov (United States)

Mustapha, Nurul Asyifah; Hu, Anyi; Yu, Chang-Ping; Sharuddin, Siti Suhailah; Ramli, Norhayati; Shirai, Yoshihito; Maeda, Toshinari

2018-04-25

Efficient approaches for the utilization of waste sewage sludge have been widely studied. One of them is to use it for the bioenergy production, specifically methane gas which is well-known to be driven by complex bacterial interactions during the anaerobic digestion process. Therefore, it is important to understand not only microorganisms for producing methane but also those for controlling or regulating the process. In this study, azithromycin analogs belonging to macrolide, ketolide, and lincosamide groups were applied to investigate the mechanisms and dynamics of bacterial community in waste sewage sludge for methane production. The stages of anaerobic digestion process were evaluated by measuring the production of intermediate substrates, such as protease activity, organic acids, the quantification of bacteria and archaea, and its community dynamics. All azithromycin analogs used in this study achieved a high methane production compared to the control sample without any antibiotic due to the efficient hydrolysis process and the presence of important fermentative bacteria and archaea responsible in the methanogenesis stage. The key microorganisms contributing to the methane production may be Clostridia, Cladilinea, Planctomycetes, and Alphaproteobacteria as an accelerator whereas Nitrosomonadaceae and Nitrospiraceae may be suppressors for methane production. In conclusion, the utilization of antibiotic analogs of macrolide, ketolide, and lincosamide groups has a promising ability in finding the essential microorganisms and improving the methane production using waste sewage sludge.

Hydrogen Evolution and Sludge Suspension During the Preparation of the First Batch of Sludge at the Savannah River Site

International Nuclear Information System (INIS)

Hay, M.S.; Lee, E.D.

1995-01-01

The first batch of High Level Radioactive Sludge for the Defense Waste Processing Facility is being prepared in two 4.9 million liter waste tanks. The preparation involves removing water soluble salts by washing (water addition, sludge suspension, settling and decantation). Sludge suspension is accomplished using long shafted slurry pumps that are mounted on rotating turntables. During the sludge suspension runs in 1993 and 1994, the slurry pumps' cleaning radius was determined to be less than that expected from previous determinations using synthetic sludge in a full size waste tank mockup. Hydrogen concentrations in the tanks' vapor space were monitored during the sludge suspension activities. As expected, the initial agitation of the sludge increased the hydrogen concentration, however, with the controls in place the hydrogen concentration was maintained below seven percent of the lower flammability limit

Hydration kinetics of cement composites with varying water-cement ratio using terahertz spectroscopy

Science.gov (United States)

Ray, Shaumik; Dash, Jyotirmayee; Devi, Nirmala; Sasmal, Saptarshi; Pesala, Bala

2015-03-01

Cement is mixed with water in an optimum ratio to form concrete with desirable mechanical strength and durability. The ability to track the consumption of major cement constituents, viz., Tri- and Dicalcium Silicates (C3S, C2S) reacting with water along with the formation of key hydration products, viz., Calcium-Silicate-Hydrate (C-S-H) which gives the overall strength to the concrete and Calcium Hydroxide (Ca(OH)2), a hydration product which reduces the strength and durability, using an efficient technique is highly desirable. Optimizing the amount of water to be mixed with cement is one of the main parameters which determine the strength of concrete. In this work, THz spectroscopy has been employed to track the variation in hydration kinetics for concrete samples with different water-cement ratios, viz., 0.3, 0.4, 0.5 and 0.6. Results show that for the sample with water-cement ratio of 0.3, significant amount of the C3S and C2S remain unreacted even after the initial hydration period of 28 days while for the cement with water-cement ratio of 0.6, most of the constituents get consumed during this stage. Analysis of the formation of Ca(OH)2 has been done which shows that the concrete sample with water-cement ratio of 0.6 produces the highest amount of Ca(OH)2 due to higher consumption of C3S/C2S in presence of excess water which is not desirable. Samples with water-cement ratio of 0.4 and 0.5 show more controlled reaction during the hydration which can imply formation of an optimized level of desired hydration products resulting in a more mechanically strong and durable concrete.

Influence of fluorosurfactants on hydrate formation rates

Energy Technology Data Exchange (ETDEWEB)

Kim, C.U.; Jeong, K.E.; Chae, H.J.; Jeong, S.Y. [Korea Reasearch Inst. of Chemical Technology, Alternative Chemicals/Fuel Research Center, Yuseong-Gu, Daejon (Korea, Republic of)

2008-07-01

Gas hydrates, or clathrates, are ice-like solids that forms when natural gas is in contact with liquid water or ice under high pressure and low temperature. There is significant interest in studying the storage and transportation of gas in the form of hydrates. However, a critical problem impacting the industrial application of gas hydrates for storage and transportation of natural gas is the slow formation rate of natural gas hydrate. Researchers have previously reported on the promotion effect of some additives on gas hydrate formation and hydrate gas content. Fluorosurfactants are significantly superior to nonfluorinated surfactants in wetting action, as well as stability in harsh environments, both thermal and chemical. This paper discussed an experimental investigation into the effects of fluorosurfactants with different ionic types on the formation of methane hydrate. The surfactants used were FSN-100 of DuPont Zonyl as non-ionic surfactant and FC-143 of DuPont as anionic surfactant. The paper discussed the experimental apparatus for methane hydrate formation. It also discussed hydrate formation kinetics and the series of hydrate formation experiments that were conducted in the presence of fluorosurfactants. Last, the paper explored the results of the study. It was concluded that anionic fluorosurfactant of FC-143 had a better promoting effect on methane hydrate formation compared with nonionic surfactant of FSN-100. 8 refs., 2 tabs., 2 figs.

Development of a test method to access the sludge reduction potential of aquatic organisms in activated sludge

NARCIS (Netherlands)

Buijs, B.R.; Klapwijk, A.; Elissen, H.J.H.; Rulkens, W.H.

2008-01-01

This article shows the development of a quantitative sludge reduction test method, which uses the sludge consuming aquatic worm Lumbriculus variegatus (Oligochaeta, Lumbriculidae). Essential for the test are sufficient oxygen supply and the presence of a non-stirred layer of sludge for burrowing of

Sewage sludge as a biomass energy source

Directory of Open Access Journals (Sweden)

Pavel Kolat

2013-01-01

Full Text Available The major part of the dry matter content of sewage sludge consists of nontoxic organic compounds, in general a combination of primary sludge and secondary microbiological sludge. The sludge also contains a substantive amount of inorganic material and a small amount of toxic components. There are many sludge-management options in which production of energy is one of the key treatment steps. The most important options are anaerobic digestion, co-digestion, incineration in combination with energy recovery and co-incineration in coal-fired power plants. The goal of our applied research is to verify, if the sludge from waste water treatment plants may be used as a biomass energy source in respect of the EU legislation, which would comply with emission limits or the proposal of energy process optimizing the preparation of coal/sludge mixture for combustion in the existing fluid bed boilers in the Czech Republic. The paper discusses the questions of thermal usage of mechanically drained stabilized sewage sludge from the waste water treatment plants in the boiler with circulated fluid layer. The paper describes methods of thermal analysis of coal, sewage sludge and its mixtures, mud transport to the circulating fluidised bed boiler, effects on efficiency, operational reliability of the combustion equipment, emissions and solid combustion residues.

Qualification testing and full-scale demonstration of titanium-treated zeolite for sludge wash processing

Energy Technology Data Exchange (ETDEWEB)

Dalton, W.J.

1997-06-30

Titanium-treated zeolite is a new ion-exchange material that is a variation of UOP (formerly Union Carbide) IONSIV IE-96 zeolite (IE-96) that has been treated with an aqueous titanium solution in a proprietary process. IE-96 zeolite, without the titanium treatment, has been used since 1988 in the West Valley Demonstration Project`s (WVDP) Supernatant Treatment System (STS) ion-exchange columns to remove Cs-137 from the liquid supernatant solution. The titanium-treated zeolite (TIE-96) was developed by Battelle-Pacific Northwest Laboratory (PNL). Following successful lab-scale testing of the PNL-prepared TIE-96, UOP was selected as a commercial supplier of the TIE-96 zeolite. Extensive laboratory tests conducted by both the WVDP and PNL indicate that the TIE-96 will successfully remove comparable quantities of Cs-137 from Tank 8D-2 high-level radioactive liquid as was done previously with IE-96. In addition to removing Cs-137, TIE-96 also removes trace quantities of Pu, as well as Sr-90, from the liquid being processed over a wide range of operating conditions: temperature, pH, and dilution. The exact mechanism responsible for the Pu removal is not fully understood. However, the Pu that is removed by the TIE-96 remains on the ion-exchange column under anticipated sludge wash processing conditions. From May 1988 to November 1990, the WVDP processed 560,000 gallons of liquid high-level radioactive supernatant waste stored in Tank 8D-2. Supernatant is an aqueous salt solution comprised primarily of soluble sodium salts. The second stage of the high-level waste treatment process began November 1991 with the initiation of sludge washing. Sludge washing involves the mixing of Tank 8D-2 contents, both sludge and liquid, to dissolve the sulfate salts present in the sludge. Two sludge washes were required to remove sulfates from the sludge.

Physical Properties of Gas Hydrates: A Review

Energy Technology Data Exchange (ETDEWEB)

Gabitto, Jorge [Prairie View A& M University; Tsouris, Costas [ORNL

2010-01-01

Methane gas hydrates in sediments have been studied by several investigators as a possible future energy resource. Recent hydrate reserves have been estimated at approximately 1016?m3 of methane gas worldwide at standard temperature and pressure conditions. In situ dissociation of natural gas hydrate is necessary in order to commercially exploit the resource from the natural-gas-hydrate-bearing sediment. The presence of gas hydrates in sediments dramatically alters some of the normal physical properties of the sediment. These changes can be detected by field measurements and by down-hole logs. An understanding of the physical properties of hydrate-bearing sediments is necessary for interpretation of geophysical data collected in field settings, borehole, and slope stability analyses; reservoir simulation; and production models. This work reviews information available in literature related to the physical properties of sediments containing gas hydrates. A brief review of the physical properties of bulk gas hydrates is included. Detection methods, morphology, and relevant physical properties of gas-hydrate-bearing sediments are also discussed.

Clathrate Hydrates for Thermal Energy Storage in Buildings: Overview of Proper Hydrate-Forming Compounds

Directory of Open Access Journals (Sweden)

Beatrice Castellani

2014-09-01

Full Text Available Increasing energy costs are at the origin of the great progress in the field of phase change materials (PCMs. The present work aims at studying the application of clathrate hydrates as PCMs in buildings. Clathrate hydrates are crystalline structures in which guest molecules are enclosed in the crystal lattice of water molecules. Clathrate hydrates can form also at ambient pressure and present a high latent heat, and for this reason, they are good candidates for being used as PCMs. The parameter that makes a PCM suitable to be used in buildings is, first of all, a melting temperature at about 25 °C. The paper provides an overview of groups of clathrate hydrates, whose physical and chemical characteristics could meet the requirements needed for their application in buildings. Simulations with a dynamic building simulation tool are carried out to evaluate the performance of clathrate hydrates in enhancing thermal comfort through the moderation of summer temperature swings and, therefore, in reducing energy consumption. Simulations suggest that clathrate hydrates have a potential in terms of improvement of indoor thermal comfort and a reduction of energy consumption for cooling. Cooling effects of 0.5 °C and reduced overheating hours of up to 1.1% are predicted.

Experience with Stabilization of SGHWR Sludge in a Commercial Plant in the United Kingdom

International Nuclear Information System (INIS)

Hagan, M.; Cornell, R.M.; Riley, B.; Ware, B.

2009-01-01

In July 2000, following a competitive tender, Nuvia Limited was contracted to design, build and commission a waste treatment plant to stabilise the active sludge stored in the External Active Sludge Tanks (EAST) at Winfrith, UK. The sludge was generated during the operational lifetime of the Steam Generating Heavy Water Reactor (SGHWR), which was in the early stages of decommissioning. This was in support of UKAEA's mission, which is to carry out environmental restoration of its nuclear sites and to put them to alternative uses wherever possible. Latterly, a new body, the Nuclear Decommissioning Authority (NDA), has become responsible for managing the UK decommissioning legacy and since 2004 UKAEA has been contracted to the NDA to deliver decommissioning work at Winfrith and other UK sites. The purpose of this commercial plant is to stabilise the radioactive sludge by encapsulation into a cement matrix within a purpose-designed 500 litre steel drum. The drum design incorporates a lost paddle mixer used to maintain homogeneity of the sludge as well as mixing it with the stabilising powders. The sludge in the EAST tanks is prepared for recovery by a process of homogenisation using in-tank stirrers. The means of reaching a narrow ratio of suspended solids within an aqueous medium will be described together with some of the problems encountered and the practical solutions devised. The material is transferred to the purpose-built Winfrith EAST Treatment Plant (WETP), where it is held in stainless steel tanks in a process area prior to being metered into a 500 litre stainless steel drum in the cell line for stabilization with powders. The cell line consists of five cells separated by shield doors designed to maintain strict contamination control. The line has a wet cell where the drums are filled with the sludge and powder, a cell with stations for curing and grouting the drums, a cell for lidding, bolting and QA inspection, a maintenance and gamma monitoring cell and a

Clinker mineral hydration at reduced relative humidities

DEFF Research Database (Denmark)

Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Lachowski, Eric E.

1999-01-01

and experimental data are presented showing that C(3)A can hydrate at lower humidities than either C3S or C2S. It is suggested that the initiation of hydration during exposure to water vapour is nucleation controlled. When C(3)A hydrates at low humidity, the characteristic hydration product is C(3)AH(6......Vapour phase hydration of purl cement clinker minerals at reduced relative humidities is described. This is relevant to modern high performance concrete that may self-desiccate during hydration and is also relevant to the quality of the cement during storage. Both the oretical considerations...

About influence of some superplasticizers on hydration and the structure of hardened cement paste

Directory of Open Access Journals (Sweden)

Koryanova Yulia

2017-01-01

Full Text Available Current construction can not be imagined without the use of high-quality mortars and concretes obtained by using high-tech and workable mixtures with lower water content. Obtaining such mixtures in current conditions is impossible without the use of superplasticizers. The use of superplasticizers in concrete technology requires an answer to the question of the influence of superplasticizers on the deformation-strength properties of cement stone. There is a well-known dependence “composition-technology-structure-properties”, from which it follows that the strength and deformation properties of cement stone directly depend on the hydration of cement stone in the early stages and structure formation. The influence of some types of superplasticizers on the hydration and structure of cement stone, namely, total, open and conditionally-closed porosity, total contraction, autogenous shrinkage, contraction porosity and hydration heat is considered in the article.

Heavy metals precipitation in sewage sludge

NARCIS (Netherlands)

Marchioretto, M.M.; Rulkens, W.H.; Bruning, H.

2005-01-01

There is a great need for heavy metal removal from strongly metal-polluted sewage sludges. One of the advantages of heavy metal removal from this type of sludge is the possibility of the sludge disposal to landfill with reduced risk of metals being leached to the surface and groundwater. Another

Comparative analysis of the efficiency, reliability, technical feasibility and costs of methods to convert sewage sludge to a hygienically safe condition

International Nuclear Information System (INIS)

Fuhrmann, D.; Leschber, R.; Mueller, G.; Jaeger, B.; Neumann, U.

1981-01-01

Due to the development of sewage treatment technology and the construction of new and sewage works and enlargement of older ones, increasing amounts of sewage sludge have been produced. Agricultural use of municipal sewage sludge is a practicable way of utilization which, however, is often limited for reasons of hygienic safety. The present study intends to describe methods of sewage sludge disinfection which have been used in practice or tested extensively, as well as technical innovations in this field, and to give information on their performance with respect to hygienic and technical requirements. A direct comparison of processes has turned out to be extremely difficult because disinfection of sewage sludge is only one of the stages of sewage treatment. For comparison, numerous factors have to be taken into account such as plant size, type of sewage and sludge treatment processes, energy costs, sales potential for agricultural use etc. This study is meant as an aid in such work. (orig.) [de

Hydration and nutrition knowledge in adolescent swimmers. Does water intake affect urine hydration markers after swimming?

Directory of Open Access Journals (Sweden)

Cesare Altavilla

2017-12-01

Full Text Available Little data exists regarding nutritional knowledge and hydration in adolescent swimmers. The aim of this study was to assess the level of nutrition and hydration knowledge and to describe the fluid balance in adolescent swimmers during training. A study was carried out with a cross-sectional descriptive part and a longitudinal part with repeated measurements over five swimming sessions. Eighty-six adolescent swimmers completed a questionnaire to assess their sport nutrition and hydration knowledge. Fluid balance and urine hydration markers were studied during training. Swimmers showed a limited nutrition knowledge (33.26 % ± SD 12.59 and meagre hydration knowledge (28.61 % ± SD 28.59. Females showed lower scores than male swimmers in nutrition and hydration knowledge. Based on urine specific gravity, swimmers started the training close to the euhydrated threshold (1.019 g/mL ± SD 0.008. Although urine specific gravity and urine colour were reduced after the training, there were minimal changes in body mass (-0.12 Kg ± SD 0.31. Sweat loss (2.67 g/min ± SD 3.23 and the net changes in the fluid balance (-0.22 % ± SD 0.59 were low. The poor knowledge in nutrition and hydration encountered in the swimmers can justify the development of a strategy to incorporate nutritional education programmes for this group. Body water deficit from swimming activity seems to be easily replaced with the water intake to maintain hydration. After the training, the urine of swimmers was diluted regardless of their water intake. Dilution of urine did not reflect real hydration state in swimming.

Methane hydrates in nature - Current knowledge and challenges

Science.gov (United States)

Collett, Timothy S.

2014-01-01

Recognizing the importance of methane hydrate research and the need for a coordinated effort, the United States Congress enacted the Methane Hydrate Research and Development Act of 2000. At the same time, the Ministry of International Trade and Industry in Japan launched a research program to develop plans for a methane hydrate exploratory drilling project in the Nankai Trough. India, China, the Republic of Korea, and other nations also have established large methane hydrate research and development programs. Government-funded scientific research drilling expeditions and production test studies have provided a wealth of information on the occurrence of methane hydrates in nature. Numerous studies have shown that the amount of gas stored as methane hydrates in the world may exceed the volume of known organic carbon sources. However, methane hydrates represent both a scientific and technical challenge, and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of methane hydrates in nature, (2) assessing the volume of natural gas stored within various methane hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural methane hydrates, (5) analyzing the methane hydrate role as a geohazard, (6) establishing the means to detect and characterize methane hydrate accumulations using geologic and geophysical data, and (7) establishing the thermodynamic phase equilibrium properties of methane hydrates as a function of temperature, pressure, and gas composition. The U.S. Department of Energy (DOE) and the Consortium for Ocean Leadership (COL) combined their efforts in 2012 to assess the contributions that scientific drilling has made and could continue to make to advance

Geologic implications of gas hydrates in the offshore of India: results of the National Gas Hydrate Program Expedition 01

Science.gov (United States)

Collett, Timothy S.; Boswell, Ray; Cochran, J.R.; Kumar, Pushpendra; Lall, Malcolm; Mazumdar, Aninda; Ramana, Mangipudi Venkata; Ramprasad, Tammisetti; Riedel, Michael; Sain, Kalachand; Sathe, Arun Vasant; Vishwanath, Krishna

2014-01-01

The Indian National Gas Hydrate Program Expedition 01 (NGHP-01) is designed to study the occurrence of gas hydrate along the passive continental margin of the Indian Peninsula and in the Andaman convergent margin, with special emphasis on understanding the geologic and geochemical controls on the occurrence of gas hydrate in these two diverse settings. The NGHP-01 expedition established the presence of gas hydrates in the Krishna-Godavari and Mahanadi Basins, and the Andaman Sea. The expedition discovered in the Krishna-Godavari Basin one of the thickest gas hydrate accumulations ever documented, in the Andaman Sea one of the thickest and deepest gas hydrate stability zones in the world, and established the existence of a fully developed gas hydrate petroleum system in all three basins.

Real-time high-resolution X-ray imaging and nuclear magnetic resonance study of the hydration of pure and Na-doped C3A in the presence of sulfates

KAUST Repository

Kirchheim, A. P.; Dal Molin, Denise Carpena Coitinho; Fischer, Peter J.; Emwas, Abdul-Hamid M.; Provis, John L.; Monteiro, Paulo José Meleragno

2011-01-01

window, combined with solution analysis by 27Al nuclear magnetic resonance (NMR) spectroscopy, was used to capture information regarding the mechanism of C3A hydration during the early stages. There are differences in the hydration mechanism between

Elementary analysis and energetic potential of the municipal sewage sludges from the Gdańsk and Kościerzyna WWTPs

Directory of Open Access Journals (Sweden)

Ostojski Arkadiusz

2018-01-01

Full Text Available This paper aims to present municipal sewage sludge (MSS elementary analysis and energetic potential based on measurement of heat of combustion (higher heating value HHV and calculation of calorific values (lower heating value LHV. The analysis takes into the consideration water content in sewage sludge, at different utilization stages, in wastewater treatment plants in Gdańsk Wschód and Kościerzyna – Pomeranian Voivodeship. The study yielded the following results (in % dry matter: ash 19÷31 %, C - 31÷36 %, H - 5÷6 %, N - 4÷6 %, O - 28÷32 %, S – 1 %. Calorific value of stabilized sludges in Gdańsk was on average 13.8÷15 MJ/kg. In case of sludges not undergoing digestion from Kościerzyna WWTP, the calorific value was at the level of 17.5 MJ/kg. Thus, sewage sludges are good energy carriers. High water content though is the problem, as it lowers the useful effect of heat. There is no alternative for thermal sewage sludge neutralization, which is in conformity with valid Polish National Waste Management Plan (KPGO 2022.

Spatial resolution of gas hydrate and permeability changes from ERT data in LARS simulating the Mallik gas hydrate production test

Science.gov (United States)

Priegnitz, Mike; Thaler, Jan; Spangenberg, Erik; Schicks, Judith M.; Abendroth, Sven

2014-05-01

The German gas hydrate project SUGAR studies innovative methods and approaches to be applied in the production of methane from hydrate-bearing reservoirs. To enable laboratory studies in pilot scale, a large reservoir simulator (LARS) was realized allowing for the formation and dissociation of gas hydrates under simulated in-situ conditions. LARS is equipped with a series of sensors. This includes a cylindrical electrical resistance tomography (ERT) array composed of 25 electrode rings featuring 15 electrodes each. The high-resolution ERT array is used to monitor the spatial distribution of the electrical resistivity during hydrate formation and dissociation experiments over time. As the present phases of poorly conducting sediment, well conducting pore fluid, non-conducting hydrates, and isolating free gas cover a wide range of electrical properties, ERT measurements enable us to monitor the spatial distribution of these phases during the experiments. In order to investigate the hydrate dissociation and the resulting fluid flow, we simulated a hydrate production test in LARS that was based on the Mallik gas hydrate production test (see abstract Heeschen et al., this volume). At first, a hydrate phase was produced from methane saturated saline water. During the two months of gas hydrate production we measured the electrical properties within the sediment sample every four hours. These data were used to establish a routine estimating both the local degrees of hydrate saturation and the resulting local permeabilities in the sediment's pore space from the measured resistivity data. The final gas hydrate saturation filled 89.5% of the total pore space. During hydrate dissociation, ERT data do not allow for a quantitative determination of free gas and remaining gas hydrates since both phases are electrically isolating. However, changes are resolved in the spatial distribution of the conducting liquid and the isolating phase with gas being the only mobile isolating phase

Role of excipients in hydrate formation kinetics of theophylline in wet masses studied by near-infrared spectroscopy

DEFF Research Database (Denmark)

Jørgensen, Anna C; Airaksinen, Sari; Karjalainen, Milja

2004-01-01

. Anhydrous theophylline was chosen as the hydrate-forming model drug compound and two excipients, silicified microcrystalline cellulose (SMCC) and alpha-lactose monohydrate, with different water absorbing properties, were used in formulation. An early stage of wet massing was studied with anhydrous...... theophylline and its 1:1 (w/w) mixtures with alpha-lactose monohydrate and SMCC with 0.1g/g of purified water. The changes in the state of water were monitored using near-infrared spectroscopy, and the conversion of the crystal structure was verified using X-ray powder diffraction (XRPD). SMCC decreased...... the hydrate formation rate by absorbing water, but did not inhibit it. The results suggest that alpha-lactose monohydrate slightly increased the hydrate formation rate in comparison with a mass comprising only anhydrous theophylline....

Simulation and Characterization of Methane Hydrate Formation

Science.gov (United States)

Dhakal, S.; Gupta, I.

2017-12-01

The ever rising global energy demand dictates human endeavor to explore and exploit new and innovative energy sources. As conventional oil and gas reserves deplete, we are constantly looking for newer sources for sustainable energy. Gas hydrates have long been discussed as the next big energy resource to the earth. Its global occurrence and vast quantity of natural gas stored is one of the main reasons for such interest in its study and exploration. Gas hydrates are solid crystalline substances with trapped molecules of gas inside cage-like crystals of water molecules. Gases such as methane, ethane, propane and carbon dioxide can form hydrates but in natural state, methane hydrates are the most common. Subsurface geological conditions with high pressure and low temperature favor the formation and stability of gas hydrates. While the occurrence and potential of gas hydrates as energy source has long been studied, there are still gaps in knowledge, especially in the quantitative research of gas hydrate formation and reservoir characterization. This study is focused on exploring and understanding the geological setting in which gas hydrates are formed and the subsequent changes in rock characteristics as they are deposited. It involves the numerical simulation of methane gas flow through fault to form hydrates. The models are representative of the subsurface geologic setting of Gulf of Mexico with a fault through layers of shale and sandstone. Hydrate formation simulated is of thermogenic origin. The simulations are conducted using TOUGH+HYDRATE, a numerical code developed at the Lawrence Berkley National Laboratory for modeling multiphase flow through porous medium. Simulation results predict that as the gas hydrates form in the pores of the model, the porosity, permeability and other rock properties are altered. Preliminary simulation results have shown that hydrates begin to form in the fault zone and gradually in the sandstone layers. The increase in hydrate

Bio-remediation of a sludge containing hydrocarbons

International Nuclear Information System (INIS)

Ayotamuno, M.J.; Okparanma, R.N.; Nweneka, E.K.; Ogaji, S.O.T.; Probert, S.D.

2007-01-01

Bio-augmentation has been used as a bio-remediation option for hydrocarbon-contaminated, oily-sludge restoration. This sludge was obtained from the Bonny-Terminal Improvement Project (BTIP) for Bonny Island, near Port Harcourt, Nigeria. Its total hydrocarbon-content (THC) was 69,372 mg/kg of sludge. Three treatment reactors (X, Y and Z) and one control reactor (A) were charged with 1500 g of oily sludge and 250 g of agricultural soil (i.e. an oily sludge to soil ratio of 6:1), the mixture homogenized and allowed to settle for seven days before various CFUs were added to reactors X, Y and Z. Reactor A did not receive any bio-preparation. The agricultural soil served both as a nutrient and a microbe carrier. With regularly scheduled mixing and watering, the THC reduction in the oily sludge varied between 40.7% and 53.2% within two weeks as well as between 63.7% and 84.5% within six weeks of applying the bio-remediation. The CFU counts of the added bio-preparation varied between 1.2 x 12 12 and 3.0 x 10 12 CFU/g of sludge and decreased to 7.0 x 10 11 CFU/g of sludge by the end of the sixth week. The pH of the degrading sludge fluctuated between 6.5 and 7.8 during the same period. When compared with the performance of the indigenous microbes in the control sample, the added bio-preparation evidently increased the THC reduction rate in the oily sludge

Sewage sludge irradiation with electrons

International Nuclear Information System (INIS)

Tauber, M.

1976-01-01

The disinfection of sewage sludge by irradiation has been discussed very intensively in the last few months. Powerful electron accelerators are now available and the main features of the irradiation of sewage sludge with fast electrons are discussed and the design parameters of such installations described. AEG-Telefunken is building an irradiation plant with a 1.5 MeV, 25 mA electron accelerator, to study the main features of electron irradiation of sewage sludge. (author)

Placement of radium/barium sludges in tailings areas

International Nuclear Information System (INIS)

Murphy, K.L.; Multamaki, G.E.

1980-01-01

Currently radium is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate the radium as radium/barium sulphate. The precipitate is allowed to settle in sedimentation basins prior to discharge of the effluent. The sedimentation basins are not suitable for final disposal of the sludge, and placement of the sludges in the tailings area has been proposed. The geochemical environment of fresh tailings areas was characterized as an acidic, oxidized surface zone underlain by an alkaline, reduced zone comprising the rest of the tailings. The quantity of sludge produced was estimated to be small relative to the quantity of tailings, and therefor a relatively small amount of radium would be added to the tailings disposal area by the addition of sludge. To confirm whether sludge addition affected radionuclide solubilization, laboratory leaching tests were conducted on slurries of acid leach tailings, and sludge-tailings mixtures. Radium in the (Ra,Ba)SO 4 sludge was at least as stable as radium in the tailings, and the sludge was able to absorb radium released from the tailings. The addition of sludge did not affect uranium and thorium solubilization. From these results it appears that the placement of sludge in tailings areas would not adversely affect the stability of radionuclides in the tailings or sludge. (auth)

Hydrothermal Testing of K Basin Sludge and N Reactor Fuel at Sludge Treatment Project Operating Conditions

Energy Technology Data Exchange (ETDEWEB)

Delegard, Calvin H.; Schmidt, Andrew J.; Thornton, Brenda M.

2007-03-30

The Sludge Treatment Project (STP), managed for the U. S. DOE by Fluor Hanford (FH), was created to design and operate a process to eliminate uranium metal from K Basin sludge prior to packaging for Waste Isolation Pilot Plant (WIPP). The STP process uses high temperature liquid water to accelerate the reaction, produce uranium dioxide from the uranium metal, and safely discharge the hydrogen. Under nominal process conditions, the sludge will be heated in pressurized water at 185°C for as long as 72 hours to assure the complete reaction (corrosion) of up to 0.25-inch diameter uranium metal pieces. Under contract to FH, the Pacific Northwest National Laboratory (PNNL) conducted bench-scale testing of the STP hydrothermal process in November and December 2006. Five tests (~50 ml each) were conducted in sealed, un-agitated reaction vessels under the hydrothermal conditions (e.g., 7 to 72 h at 185°C) of the STP corrosion process using radioactive sludge samples collected from the K East Basin and particles/coupons of N Reactor fuel also taken from the K Basins. The tests were designed to evaluate and understand the chemical changes that may be occurring and the effects that any changes would have on sludge rheological properties. The tests were not designed to evaluate engineering aspects of the process. The hydrothermal treatment affected the chemical and physical properties of the sludge. In each test, significant uranium compound phase changes were identified, resulting from dehydration and chemical reduction reactions. Physical properties of the sludge were significantly altered from their initial, as-settled sludge values, including, shear strength, settled density, weight percent water, and gas retention.

Anaerobic digestion of industrial activated aerobic sludge

International Nuclear Information System (INIS)

Goodloe, J.G.; Roberts, R.S.

1990-04-01

The Tennessee Eastman Company manufactures a variety of organic chemicals, plastics and fibers at their Kingsport Tennessee Facility. The wastewater generated during the manufacture of these compounds is currently treated using an activated sludge process. The objective of the project is to evaluate the economic potential of an anaerobic digestion process to convert industrial sludge at the Tennessee Eastman Company into biogas. The evaluation will require collection and analysis of experimental data on the anaerobic digestion of industrial sludge obtained from Kingsport. Although the experiments will be conducted using Tennessee Eastman sludge, these results should be also generally applicable to similar industrial sludge

Integral study of sewage sludges

International Nuclear Information System (INIS)

1994-01-01

Sewage sludges are the by-product generated during the treatment process of waste water, and they are conformed by a solid phase which origin is the accumulation of pollutant materials which has been added to water during natural and anthropogenic activities. Its handling is one of the most serious problems faced by water treatment plants which involve the production, gathering, transportation, re utilization and final disposal of sewage sludges. The main purpose of this project is to perform a technical evaluation of the process of sewage sludge irradiation for its possible application as a choice for treatment and final disposal. Irradiation with gammas from Cobalt-60 shows effectiveness in disinfestation of sewage sludges, since they reduce six times the microbial population with a 7 KGy dose. In like manners with doses of 10 KGy is possible to bring down in 70 % the concentration of organic compounds, as well as to eliminate the presence of 6 to 22 organic compounds on samples of sewage sludges. The whole content of this work is presented in six sections: Introduction, Antecedents, Methodology, Conclusions, Suggestions and Bibliography. (Author)

Effect of sludge solids to mono-sodium titanate (MST) ratio on MST-treated sludge

International Nuclear Information System (INIS)

Saito, H.H.

1999-01-01

The Salt Disposition Systems Engineering Team has selected two cesium removal technologies for further development to replace the In-Tank Precipitation process: small tank tetraphenylborate (TPB) precipitation and crystalline silicotitanate (CST) ion exchange. In the CST ion exchange process, incoming salt solution from storage tanks containing entrained sludge solids is pretreated with monosodium titanate (MST) to adsorb strontium and plutonium. The resulting slurry is filtered using a cross-flow filter, with the permeate sent forward to CST ion exchange columns for cesium removal prior to conversion into Class A grout at the Saltstone Facility. The MST and sludge solids are to be sent for vitrification at the Defense Waste Processing Facility (DWPF). The High Level Waste Division (HLWD) requested that the Waste Processing Technology Section (WPTS) study varying the insoluble sludge solids to MST ratio to determine the relative impact of sludge and MST on filter performance. The purpose of this study was not for an exhaustive comprehensive search for an optimized insoluble sludge solids to monosodium titanate (MST) ratio, but as a scoping study to identify any effects of having an excess of either material. This document reports the results obtained

Composting sewage sludge

International Nuclear Information System (INIS)

Epstein, E.

1979-01-01

Sewage sludge is predominantly organic matter containing domestic and industrial wastes. The inefficiency of the waste water treatment to destroy pathogens and stabilization of odor-producing volatile organic compounds necessitates further treatment before sludge can be used as a soil amendment or fertilizer. Composting, which is the rapid biological decomposition of the sludge organic matter is an excellent method of sludge stabilization. During the process, volatile organics are decomposed and many of the pathogens destoyed. The low cost of the process and its flexibility with respect to labor and capital makes the system highly attractive to municipalities. A major problem facing large urban waste water treatment facilities is the distribution or marketing. The light weight of the material, expensive hauling costs, and low fertilizer value reduce its attractiveness to the agricultural sector. Thus, the greatest market is for horticultural purposes, sod, nurseries, greenhouses, parks, and reclamation areas. The major potential benefits of irradiating compost as a means of further disinfection are: (1) elimination of any health hazard; (2) increase of market potential, i.e., providing more market outlets to distribute the material; (3) compliance with state and federal health regulations; and (4) enhancement of the economics of composting as a result of utilizing compost in speciality products commanding a higher value

Method of treating radioactive sludge waste

International Nuclear Information System (INIS)

Shoji, Yuichi; Matsuura, Hiroyuki; Ichihashi, Toshio

1989-01-01

For removing water content from sludge wastes, filtration or steam condensation may be considered, but none of them can sufficiently reduce the water content since filtration may cause clogging and steam treatment has a limit in the condensation. In view of the above, radioactive sludge wastes are dehydrated by an electroosmotic process in a vessel and then dehydrated solid contents are solidified in the vessel. Since the sludge wastes are mainly composed o fion exchange resins and iron oxides deposited to the resins, when a DC voltage is applied to the sludges containing such solid contents, a force tending to premeate them through the fine pores in the filter is exerted to water. As a result, only water is removed while the solids are being held on the filters. Since the moving direction of water is different depending on the property of the sludges, the polarity of the electrodes may be changed depending on the nature of the sludges. Thus, volume reduction can be improved and treating conditions can be controlled easily by a simple device. (N.H.)

Electrochemical pretreatment of waste activated sludge: effect of process conditions on sludge disintegration degree and methane production.

Science.gov (United States)

Ye, Caihong; Yuan, Haiping; Dai, Xiaohu; Lou, Ziyang; Zhu, Nanwen

2016-11-01

Waste activated sludge (WAS) requires a long digestion time because of a rate-limiting hydrolysis step - the first phase of anaerobic digestion (AD). Pretreatment can be used prior to AD to facilitate the hydrolysis step and improve the efficiency of WAS digestion. This study evaluated a novel application of electrochemical (EC) technology employed as the pretreatment method prior to AD of WAS, focusing on the effect of process conditions on sludge disintegration and subsequent AD process. A superior process condition of EC pretreatment was obtained by reaction time of 30 min, electrolysis voltage of 20 V, and electrode distance of 5 cm, under which the disintegration degree of WAS ranged between 9.02% and 9.72%. In the subsequent batch AD tests, 206 mL/g volatile solid (VS) methane production in EC pretreated sludge was obtained, which was 20.47% higher than that of unpretreated sludge. The AD time was 19 days shorter for EC pretreated sludge compared to the unpretreated sludge. Additionally, the EC + AD reactor achieved 41.84% of VS removal at the end of AD. The analysis of energy consumption showed that EC pretreatment could be effective in enhancing sludge AD with reduced energy consumption when compared to other pretreatment methods.

On the influence of sewage sludge irradiation by gamma radiation on the sludge properties

International Nuclear Information System (INIS)

Hegemann, W.

1976-01-01

The gamma irradiation is a technically usable method to disinfect sewage sludge. Furthermore, the slurry properties are also improved. After 24 hours' thickening time, a significantly smaller volume of concentrated thick slurry could be removed compared to untreated sludge. On the other hand, a dilution occurs with pasteurization if the heat is introduced by steam, and the initial concentration could not be achieved again even after thickening for 24 hours. The drainability of the treated sludge was also improved by irradiation, expressed by a reduction of the specific filter resistance. The costs are essentially determined by the radiation sources used. If it is technically possible to process reactor wastes in such a manner that they can be used in slurry radiation plants, costs of 3.50-4.00 DM/m 3 treated sludge seem possible. (orig.) [de

Heat Transfer Analysis of Methane Hydrate Sediment Dissociation in a Closed Reactor by a Thermal Method

Directory of Open Access Journals (Sweden)

Mingjun Yang

2012-05-01

Full Text Available The heat transfer analysis of hydrate-bearing sediment involved phase changes is one of the key requirements of gas hydrate exploitation techniques. In this paper, experiments were conducted to examine the heat transfer performance during hydrate formation and dissociation by a thermal method using a 5L volume reactor. This study simulated porous media by using glass beads of uniform size. Sixteen platinum resistance thermometers were placed in different position in the reactor to monitor the temperature differences of the hydrate in porous media. The influence of production temperature on the production time was also investigated. Experimental results show that there is a delay when hydrate decomposed in the radial direction and there are three stages in the dissociation period which is influenced by the rate of hydrate dissociation and the heat flow of the reactor. A significant temperature difference along the radial direction of the reactor was obtained when the hydrate dissociates and this phenomenon could be enhanced by raising the production temperature. In addition, hydrate dissociates homogeneously and the temperature difference is much smaller than the other conditions when the production temperature is around the 10 °C. With the increase of the production temperature, the maximum of ΔT_oi grows until the temperature reaches 40 °C. The period of ΔT_oi have a close relation with the total time of hydrate dissociation. Especially, the period of ΔT_oi with production temperature of 10 °C is twice as much as that at other temperatures. Under these experimental conditions, the heat is mainly transferred by conduction from the dissociated zone to the dissociating zone and the production temperature has little effect on the convection of the water in the porous media.

The chemical and mechanical differences between alginate-like exopolysaccharides isolated from aerobic flocculent sludge and aerobic granular sludge

NARCIS (Netherlands)

Lin, Y. M.; Sharma, P. K.; van Loosdrecht, M. C. M.

2013-01-01

This study aimed to investigate differences in the gel matrix of aerobic granular sludge and normal aerobic flocculent sludge. From both types of sludge that fed with the same municipal sewage, the functional gel-forming exopolysaccharides, alginate-like exopolysaccharides, were isolated. These two

Plant available nitrogen from anaerobically digested sludge and septic tank sludge applied to crops grown in the tropics.

Science.gov (United States)

Sripanomtanakorn, S; Polprasert, C

2002-04-01

Agricultural land is an attractive alternative for the disposal of biosolids since it utilises the recyclable nutrients in the production of crops. In Thailand and other tropical regions, limited field-study information exists on the effect of biosolids management strategies on crop N utilisation and plant available N (PAN) of biosolids. A field study was conducted to quantify the PAN of the applied biosolids, and to evaluate the N uptake rates of some tropical crops. Sunflower (Helianthus annuus) and tomato (Lycopersicon esculentum) were chosen in this study. Two types of biosolids used were: anaerobically digested sludge and septic tank sludge. The soil is acid sulfate and is classified as Sulfic Tropaquepts with heavy clay in texture. The anaerobically digested sludge applied rates were: 0, 156 and 312 kg N ha(-1) for the sunflower plots, and 0, 586, and 1172 kg N ha(-1) for the tomato plots. The septic tank sludge applied rates were: 0, 95 and 190 kg N ha(-1) for the sunflower plots, and 0, 354 and 708 kg N ha(-1) for the tomato plots, respectively. The results indicated the feasibility of applying biosolids to grow tropical crops. The applications of the anaerobically digested sludge and the septic tank sludge resulted in the yields of sunflower seeds and tomato fruits and the plant N uptakes comparable or better than that applied with only the chemical fertiliser. The estimated PAN of the anaerobically digested sludge was about 27-42% of the sludge organic N during the growing season. For the septic tank sludge, the PAN was about 15-58% of the sludge organic N. It is interesting to observe that an increase of the rate of septic tank sludge incorporated into this heavy clay soil under the cropping system resulted in the decrease of N mineralisation rate. This situation could cause the reduction of yield and N uptake of crops.

Enhanced sludge washing evaluation plan

Energy Technology Data Exchange (ETDEWEB)

Jensen, R.D.

1994-09-01

The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices.

Enhanced sludge washing evaluation plan

International Nuclear Information System (INIS)

Jensen, R.D.

1994-09-01

The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices

REEMISSION OF MERCURY COMPOUNDS FROM SEWAGE SLUDGE DISPOSAL

Directory of Open Access Journals (Sweden)

Beata Janowska

2016-12-01

Full Text Available The sewage sludge disposal and cultivation methods consist in storage, agricultural use, compost production, biogas production or heat treatment. The sewage sludge production in municipal sewage sludge treatment plants in year 2013 in Poland amounted to 540.3 thousand Mg d.m. The sewage sludge for agricultural or natural use must satisfy chemical, sanitary and environmental safety requirements. The heavy metal content, including the mercury content, determines the sewage sludge disposal method. Mercury has a high chemical activity and biological form compounds with different properties. The properties of the mercury present in sewage sludge or composts, its potential bioavailability depend on its physicochemical forms. Different forms of mercury, which are found in soil and sediments and sewage sludge, may be determined using various techniques sequential extraction. In order to assess the bioavailability the analysis of fractional of mercury in samples of sewage sludge and composts was made. For this purpose the analytical procedure based on a four sequential extraction process was applied. Mercury fractions were classified as exchangeable (EX, base soluble (BS, acids soluble (AS and oxidizable (OX. This article presents the research results on the mercury compounds contents in sewage sludge subjected to drying process, combustion and in composted sewage sludge. During drying and combustion process of the sewage sludge, mercury transforms into volatile forms that could be emitted into the atmosphere. The mercury fractionation in composted sewage sludge proved that mercury in compost occurs mainly in an organic fraction and in a residual fraction that are scarce in the environment.

Seismic reflections associated with submarine gas hydrates

Energy Technology Data Exchange (ETDEWEB)

Andreassen, K

1996-12-31

Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

Seismic reflections associated with submarine gas hydrates

Energy Technology Data Exchange (ETDEWEB)

Andreassen, K.

1995-12-31

Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

40 CFR 61.54 - Sludge sampling.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Sludge sampling. 61.54 Section 61.54... sampling. (a) As an alternative means for demonstrating compliance with § 61.52(b), an owner or operator... days prior to a sludge sampling test, so that he may at his option observe the test. (c) Sludge shall...

Pentachlorophenol (PCP) sludge recycling unit

International Nuclear Information System (INIS)

1994-08-01

The Guelph Utility Pole Company treats utility poles by immersion in pentachlorophenol (PCP) or by pressure treatment with chromated copper arsenate (CCA). The PCP treatment process involves a number of steps, each producing a certain amount of sludge and other wastes. In a plant upgrading program to improve processing and treatment of poles and to reduce and recycle waste, a PCP recovery unit was developed, first as an experimental pilot-scale unit and then as a full-scale unit. The PCP recovery unit is modular in design and can be modified to suit different requirements. In a recycling operation, the sludge is pumped through a preheat system (preheated by waste heat) and suspended solids are removed by a strainer. The sludge is then heated in a tank and at a predetermined temperature it begins to separate into its component parts: oil, steam, and solids. The steam condenses to water containing low amounts of light oil, and this water is pumped through an oil/water separator. The recovered oil is reused in the wood treatment process and the water is used in the CCA plant. The oil remaining in the tank is reused in PCP treatment and the solid waste, which includes small stones and wood particles, is removed and stored. By the third quarter of operation, the recovery unit was operating as designed, processing ca 10,000 gal of sludge. This sludge yielded 6,500 gal of water, 3,500 gal of oil, and ca 30 gal of solids. Introduction of the PCP sludge recycling system has eliminated long-term storage of PCP sludge and minimized costs of hazardous waste disposal. 4 figs

Experience in the transfer of oil sludge from Kemaman supply base (KSB) Terengganu

International Nuclear Information System (INIS)

Bustami Abu; Ibrahim Martibi; Mazlan Mohamad; Nik Marzukee

2005-01-01

EPMI and MINT had signed a contract for transferring 2400 drums containing oil sludge waste from Kemaman Supply Base (KSB), Terengganu to MINT, Bangi with a cost of RM 2.5 million. The work was done in two stages; the first stage involved 800 drums and the second stage involved 1600 drums. The preparation and implementation work involved application to obtain approval from the Atomic Energy Licensing Board (AELB) and Department of Environment (DOE) as the transportation has to comply with transport regulations for radioactive and toxic waste, appointing transport company, providing information and briefing to supervisors / workers regarding radiation as well as other safety aspects during transfer of waste. (Author)

Assessment of mobility and bioavailability of mercury compounds in sewage sludge and composts.

Science.gov (United States)

Janowska, Beata; Szymański, Kazimierz; Sidełko, Robert; Siebielska, Izabela; Walendzik, Bartosz

2017-07-01

Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes. The experimental setup comprises the composing process of the sewage sludge containing 13.1mgkg -1 of the total mercury, performed in static reactors with forced aeration. In order to evaluate the bioavailability of mercury, its fractionation was performed in sewage sludge and composts during the process. An analytical procedure based on four-stage sequential extraction was applied to determine the mercury content in the ion exchange (water soluble and exchangeable Hg), base soluble (Hg bound to humic and fulvic acid), acid soluble (Hg bound to Fe/Mn oxides and carbonates) and oxidizable (Hg bound to organic matter and sulphide) fractions. The results showed that from 50.09% to 64.55% of the total mercury was strongly bound to organo-sulphur and inorganic sulphide; that during composting, increase of concentrations of mercury compounds strongly bound with organic matter and sulphides; and that mercury content in the base soluble and oxidizable fractions was strongly correlated with concentration of dissolved organic carbon in those fractions. Copyright © 2017 Elsevier Inc. All rights reserved.

REEMISSION OF MERCURY COMPOUNDS FROM SEWAGE SLUDGE DISPOSAL

OpenAIRE

Beata Janowska

2016-01-01

The sewage sludge disposal and cultivation methods consist in storage, agricultural use, compost production, biogas production or heat treatment. The sewage sludge production in municipal sewage sludge treatment plants in year 2013 in Poland amounted to 540.3 thousand Mg d.m. The sewage sludge for agricultural or natural use must satisfy chemical, sanitary and environmental safety requirements. The heavy metal content, including the mercury content, determines the sewage sludge disposal metho...

Factors affecting the consolidation of steam generator sludge

Energy Technology Data Exchange (ETDEWEB)

Turner, C. W.; Shamsuzzaman, K.; Tapping, R. L.

1993-02-15

It is hypothesized that sludge consolidation is promoted by chemical reactions involving the various sludge constituents, although the hardness of the final product will also depend on the total porosity. Oxidizing conditions and higher temperatures produce a harder sludge. The precipitation of Zn{sub 2}SiO{sub 4}, a potential binding agent, may also promote sludge consolidation. Several solutions to prevent sludge consolidation are suggested. (Author) 3 figs., 4 tabs., 3 refs.

Membrane bioreactor (MBR) sludge inoculation in a hybrid process scheme concept to assist overloaded conventional activated sludge (CAS) process operations.

Science.gov (United States)

Fenu, A; Roels, J; Van Damme, S; Wambecq, T; Weemaes, M; Thoeye, C; De Gueldre, G; Van De Steene, B

2012-01-01

This study analyzes the effect of inoculating membrane bioreactor (MBR) sludge in a parallel-operated overloaded conventional activated sludge (CAS) system. Modelling studies that showed the beneficial effect of this inoculation were confirmed though full scale tests. Total nitrogen (TN) removal in the CAS increased and higher nitrate formation rates were achieved. During MBR sludge inoculation, the TN removal in the CAS was proven to be dependent on MBR sludge loading. Special attention was given to the effect of inoculation on sludge quality. The MBR flocs, grown without selection pressure, were clearly distinct from the more compact flocs in the CAS system and also contained more filamentous bacteria. After inoculation the MBR flocs did not evolve into good-settling compact flocs, resulting in a decreasing sludge quality. During high flow conditions the effluent CAS contained more suspended solids. Sludge volume index, however, did not increase. Laboratory tests were held to determine the threshold volume of MBR sludge to be seeded into the CAS reactor. Above 16-30%, supernatant turbidity and scum formation increased markedly.

Waste sludge resuspension and transfer: development program

International Nuclear Information System (INIS)

Weeren, H.O.; Mackey, T.S.

1980-02-01

The six Gunite waste tanks at Oak Ridge National Laboratory (ORNL) contain about 400,000 gal of sludge that has precipitated from solution and settled during the 35 years these tanks have been in service. Eventual decommissioning of the tanks has been proposed. The first part of this program is to resuspend the accumulated sludge, to transfer it to new storage tanks in Melton Valley, and to dispose of it by the shale-fracturing process. On the basis of preliminary information, a tentative operational concept was adopted. The sludge in each tank would be resuspended by hydraulic sluicing and pumped from the tank. This resuspended sludge would be treated as necessary to keep the particles in suspension and would be pumped to the new waste-storage tanks. Subsequently the sludge would be pumped from the tanks, combined with a cement-base mix, and disposed of by the shale-fracturing facility. Verification of the feasibility of this concept required development effort on characterization of the sludge and development of techniques for resuspending the sludge and for keeping it in suspension. These development efforts are described in this report. Sections of the report describe both the known properties of the sludge and the tests of grinding methods investigated, discuss tests of various suspenders, describe tests with cement-base mixes, summarize hot-cell tests on actual sludge samples, and describe tests that were made at a mockup of a Gunite tank installation. On the basis of the tests made, it was concluded that reslurrying and resuspension of the sludge is quite feasible and that the suspensions can be made compatible with cement mixes

Full-scale effects of addition of sludge from water treatment stations into processes of sewage treatment by conventional activated sludge.

Science.gov (United States)

Luiz, Marguti André; Sidney Seckler, Ferreira Filho; Passos, Piveli Roque

2018-06-01

An emerging practice for water treatment plant (WTP) sludge is its disposal in wastewater treatment plants (WWTP), an alternative that does not require the installation of sludge treatment facilities in the WTP. This practice can cause both positive and negative impacts in the WWTP processes since the WTP sludge does not have the same characteristics as domestic wastewater. This issue gives plenty of information in laboratory and pilot scales, but lacks data from full-scale studies. The main purpose of this paper is to study the impact of disposing sludge from the Rio Grande conventional WTP into the ABC WWTP, an activated sludge process facility. Both plants are located in São Paulo, Brazil, and are full-scale facilities. The WTP volumetric flow rate (4.5 m³/s) is almost three times that of WWTP (1.6 m³/s). The data used in this study came from monitoring the processes at both plants. The WWTP liquid phase treatment analysis included the variables BOD, COD, TSS, VSS, ammonia, total nitrogen, phosphorus and iron, measured at the inlet, primary effluent, mixed liquor, and effluent. For the WWTP solids treatment, the parameters tested were total and volatile solids. The performance of the WWTP process was analyzed with and without sludge addition: 'without sludge' in years 2005 and 2006 and 'with sludge' from January 2007 to March 2008. During the second period, the WTP sludge addition increased the WWTP removal efficiencies for solids (93%-96%), organic matter (92%-94% for BOD) and phosphorus (52%-88%), when compared to the period 'without sludge'. These improvements can be explained by higher feed concentrations combined to same or lower effluent concentrations in the 'with sludge' period. No critical negative impacts occurred in the sludge treatment facilities, since the treatment units absorbed the extra solids load from the WTP sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Radioactivity of sludge in Finland in 1987

International Nuclear Information System (INIS)

Puhakainen, M.; Rahola, T.

1989-05-01