Treatment of Lagoon sludge waste generated from Uranium Conversion Plant

International Nuclear Information System (INIS)

Hwang, D.S.; Oh, J.H.; Lee, K.I.; Choi, Y.D.; Hwang, S.T.; Park, J.H.

2003-01-01

This study investigated the dissolution property of nitrate salts in the desalination process by water and the drying property of residual solid after separating nitrates in a series of processes for the sludge treatment. Desalination was carried out with the adding ratio of water and drying property was analyzed by TG/DTA, FTIR, and XRD. Nitrate salts involved in the sludge were separated over 97 % at the water adding ratio of 2.5. But a small quantity of calcium and sodium nitrate remained in the residue. These were decomposed over 600 deg. C while calcium carbonate, which was a main compound of residual solid, was decomposed into calcium oxide over 750 deg. C. The residual solid has to be decomposed over 800 deg. C to converse uranyl nitrate of six values into the stable U 3 O 8 of four values. As a result of removing the nitrates at the adding ratio of 2.5 and drying the residue over 900 deg. C, volume of the sludge waste decreased over 80 %. (authors)

Treatment aerobic conjugate of sludges of septic tanks and household organic solid wastes

Directory of Open Access Journals (Sweden)

Wanderson Barbosa da Silva Feitosa

2009-12-01

Full Text Available It was aimed at to evaluate the co-composting as technological alternative to the treatment of sludges of septic tanks with household organic solid wastes originating from cities of small and medium loads. The sludges and the domiciliary organic solid waste were collected in Cabaceiras, Caraúbas and Queimadas, state of Paraíba. The experiment consisted of four treatments with three repetitions, totaling 12 reactors, of cylindrical configuration in polyethylene of 100 L of capacity. Each reactor was fed with 50 kg substratum with variable composition in function of the sludge fraction: 0%, 10%, 20% and 30%. The manual turning was accomplished three times a week and the temperature was monitored daily. The total destruction of helminth eggs in period differentiated in function of the sludges fraction (14, 28, 35 and 63 days and the medium transformation of 54.1% of sludges in biosolids class A and class B, with favorable characteristics to the use in agricultural cultures in 91 days, expressed the viability of the treatment for co-composting of sludges of tanks septic multichamber of collective use for the cities of small and medium load.

Gas Generation from K East Basin Sludges - Series I Testing

International Nuclear Information System (INIS)

Delegard, Calvin H.; Bryan, Samuel A.; Schmidt, Andrew J.; Bredt, Paul R.; King, Christopher M.; Sell, Rachel L.; Burger, Leland L.; Silvers, Kurt L.

2000-01-01

This report describes work to examine the gas generation behavior of actual K East (KE) Basin floor and canister sludge. The path forward for management of the K Basin Sludge is to retrieve, ship, and store the sludge at T Plant until final processing at some future date. Gas generation will impact the designs and costs of systems associated with retrieval, transportation and storage of sludge. The overall goals for this testing were to collect detailed gas generation rate and composition data to ascertain the quantity and reactivity of the metallic uranium (and other reactive species) present in the K Basin sludge. The gas generation evaluation included four large-scale vessels (850 ml) and eight small-scale vessels (30 ml) in an all-metal, leak tight system. The tests were conducted for several thousand hours at ambient and elevated temperatures (32 C, 40 C, 60 C, 80 C, and 95 C) to accelerated the reactions and provide conclusive gas generation data within a reasonable testing period. The sludge used for these tests was collected from the KE Basin floor and canister barrels (containing damaged spent fuel elements) using a consolidated sampling technique (i.e., material from several locations was combined to form ''consolidated samples''). Portions of these samples were sieved to separate particles greater than 250 m (P250) from particle less than 250 m (M250). This separation was performed to mimic the separation operations that are planned during the retrieval of certain K Basin sludge types and to gain a better understanding of how uranium metal is distributed in the sludge. The corrosion rate of the uranium metal particles in the sludge was found to agree reasonably well with corrosion rates reported in the literature

Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells

KAUST Repository

Yang, Fei

2013-01-01

Single-chamber air-cathode microbial fuel cells (MFCs) were used to generate electricity from fermented primary sludge. Fermentation (30°C, 9days) decreased total suspended solids (26.1-16.5g/L), volatile suspended solids (24.1-15.3g/L) and pH (5.7-4.5), and increased conductivity (2.4-4.7mS/cm), soluble COD (2.66-15.5g/L), and volatile fatty acids (1.9-10.1g/L). To lower the COD and increase pH, fermentation supernatant was diluted with primary effluent before being used in the MFCs. The maximum power density was 0.32±0.01W/m2, compared to 0.24±0.03W/m2 with only primary effluent. Power densities were higher with phosphate buffer added to the supernatant (1.03±0.06W/m2) or the solution (0.87±0.05W/m2). Coulombic efficiencies ranged from 18% to 57%, and sCOD removals from 84% to 94%. These results demonstrated that sludge can effectively be used for power generation when fermented and then diluted with only primary effluent. © 2012 Elsevier Ltd.

Effects of Time, Heat, and Oxygen on K Basin Sludge Agglomeration, Strength, and Solids Volume

Energy Technology Data Exchange (ETDEWEB)

Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Daniel, Richard C.; Burns, Carolyn A.

2011-01-04

Sludge disposition will be managed in two phases under the K Basin Sludge Treatment Project. The first phase is to retrieve the sludge that currently resides in engineered containers in the K West (KW) Basin pool at ~10 to 18°C. The second phase is to retrieve the sludge from interim storage in the sludge transport and storage containers (STSCs) and treat and package it in preparation for eventual shipment to the Waste Isolation Pilot Plant. The work described in this report was conducted to gain insight into how sludge may change during long-term containerized storage in the STSCs. To accelerate potential physical and chemical changes, the tests were performed at temperatures and oxygen partial pressures significantly greater than those expected in the T Plant canyon cells where the STSCs will be stored. Tests were conducted to determine the effects of 50°C oxygenated water exposure on settled quiescent uraninite (UO2) slurry and a full simulant of KW containerized sludge to determine the effects of oxygen and heat on the composition and mechanical properties of sludge. Shear-strength measurements by vane rheometry also were conducted for UO2 slurry, mixtures of UO2 and metaschoepite (UO3•2H2O), and for simulated KW containerized sludge. The results from these tests and related previous tests are compared to determine whether the settled solids in the K Basin sludge materials change in volume because of oxidation of UO2 by dissolved atmospheric oxygen to form metaschoepite. The test results also are compared to determine if heating or other factors alter sludge volumes and to determine the effects of sludge composition and settling times on sludge shear strength. It has been estimated that the sludge volume will increase with time because of a uranium metal → uraninite → metaschoepite oxidation sequence. This increase could increase the number of containers required for storage and increase overall costs of sludge management activities. However, the volume

Effects of Time, Heat, and Oxygen on K Basin Sludge Agglomeration, Strength, and Solids Volume

International Nuclear Information System (INIS)

Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Daniel, Richard C.; Burns, Carolyn A.

2011-01-01

Sludge disposition will be managed in two phases under the K Basin Sludge Treatment Project. The first phase is to retrieve the sludge that currently resides in engineered containers in the K West (KW) Basin pool at ∼10 to 18 C. The second phase is to retrieve the sludge from interim storage in the sludge transport and storage containers (STSCs) and treat and package it in preparation for eventual shipment to the Waste Isolation Pilot Plant. The work described in this report was conducted to gain insight into how sludge may change during long-term containerized storage in the STSCs. To accelerate potential physical and chemical changes, the tests were performed at temperatures and oxygen partial pressures significantly greater than those expected in the T Plant canyon cells where the STSCs will be stored. Tests were conducted to determine the effects of 50 C oxygenated water exposure on settled quiescent uraninite (UO 2 ) slurry and a full simulant of KW containerized sludge to determine the effects of oxygen and heat on the composition and mechanical properties of sludge. Shear-strength measurements by vane rheometry also were conducted for UO 2 slurry, mixtures of UO2 and metaschoepite (UO 3 · 2H 2 O), and for simulated KW containerized sludge. The results from these tests and related previous tests are compared to determine whether the settled solids in the K Basin sludge materials change in volume because of oxidation of UO2 by dissolved atmospheric oxygen to form metaschoepite. The test results also are compared to determine if heating or other factors alter sludge volumes and to determine the effects of sludge composition and settling times on sludge shear strength. It has been estimated that the sludge volume will increase with time because of a uranium metal → uraninite → metaschoepite oxidation sequence. This increase could increase the number of containers required for storage and increase overall costs of sludge management activities. However, the

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)

Gas Generation from K East Basin Sludges and Irradiated Metallic Uranium Fuel Particles Series III Testing

International Nuclear Information System (INIS)

Schmidt, Andrew J.; Delegard, Calvin H.; Bryan, Samuel A.; Elmore, Monte R.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

2003-01-01

The path forward for managing of Hanford K Basin sludge calls for it to be packaged, shipped, and stored at T Plant until final processing at a future date. An important consideration for the design and cost of retrieval, transportation, and storage systems is the potential for heat and gas generation through oxidation reactions between uranium metal and water. This report, the third in a series (Series III), describes work performed at the Pacific Northwest National Laboratory (PNNL) to assess corrosion and gas generation from irradiated metallic uranium particles (fuel particles) with and without K Basin sludge addition. The testing described in this report consisted of 12 tests. In 10 of the tests, 4.3 to 26.4 g of fuel particles of selected size distribution were placed into 60- or 800-ml reaction vessels with 0 to 100 g settled sludge. In another test, a single 3.72-g fuel fragment (i.e., 7150-mm particle) was placed in a 60 ml reaction vessel with no added sludge. The twelfth test contained only sludge. The fuel particles were prepared by crushing archived coupons (samples) from an irradiated metallic uranium fuel element. After loading the sludge materials (whether fuel particles, mixtures of fuel particles and sludge, or sludge-only) into reaction vessels, the solids were covered with an excess of K Basin water, the vessels closed and connected to a gas measurement manifold, and the vessels back-flushed with inert neon cover gas. The vessels were then heated to a constant temperature. The gas pressures and temperatures were monitored continuously from the times the vessels were purged. Gas samples were collected at various times during the tests, and the samples analyzed by mass spectrometry. Data on the reaction rates of uranium metal fuel particles with water as a function of temperature and particle size were generated. The data were compared with published studies on metallic uranium corrosion kinetics. The effects of an intimate overlying sludge layer

K Basin Sludge Conditioning Testing. Nitric Acid Dissolution Testing of K East Area Sludge Composite, Small- and Large-Scale Testing

International Nuclear Information System (INIS)

Carlson, C.D.; Delegard, C.H.; Burgeson, I.E.; Schmidt, A.J.; Silvers, K.L.

1998-01-01

This report describes work performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) to support the development of the K Basin Sludge Treatment System. For this work, testing was performed to examine the dissolution behavior of a K East Basin floor and Weasel Pit sludge composite, referred to as K East area sludge composite, in nitric acid at the following concentrations: 2 M, 4 M, 6 M and 7.8 M. With the exception of one high solids loading test the nitric acid was added at 4X the stoichiometric requirement (assuming 100% of the sludge was uranium metal). The dissolution tests were conducted at boiling temperatures for 24 hours. Most of the tests were conducted with approximately2.5 g of sludge (dry basis). The high solids loading test was conducted with approximately7 g of sludge. A large-scale dissolution test was conducted with 26.5 g of sludge and 620 mL of 6 M nitric acid. The objectives of this test were to (1) generate a sufficient quantity of acid-insoluble residual solids for use in leaching studies, and (2) examine the dissolution behavior of the sludge composite at a larger scale

Effect of hydrothermal treatment temperature on the properties of sewage sludge derived solid fuel

Directory of Open Access Journals (Sweden)

Mi Yan

2015-10-01

Full Text Available High moisture content along with poor dewaterability are the main challenges for sewage sludge treatment and utilization. In this study, the effect of hydrothermal treatment at various temperature (120-200 ˚C on the properties of sewage sludge derived solid fuel was investigated in the terms of mechanical dewatering character, drying character, calorific value and heavy metal distribution. Hydrothermal treatment (HT followed by dewatering process significantly reduced moisture content and improved calorific value of sewage sludge with the optimum condition obtained at 140˚C. No significant alteration of drying characteristic was produced by HT. Heavy metal enrichment in solid particle was found after HT that highlighted the importance of further study regarding heavy metal behavior during combustion. However, it also implied the potential application of HT on sewage sludge for heavy metal removal from wastewater.

Investigation of Rheological Impacts on Sludge Batch 3 as Insoluble Solids and Wash Endpoints are Adjusted

International Nuclear Information System (INIS)

Fellinger, T. L.

2005-01-01

The Defense Waste Processing Facility (DWPF) is currently processing and immobilizing radioactive sludge slurry into a durable borosilicate glass. The DWPF has already processed three sludge batches (Sludge Batch 1A, Sludge Batch 1B, and Sludge Batch 2) and is currently processing the fourth sludge batch (Sludge Batch 3). A sludge batch is defined as a single tank of sludge slurry or a combination of sludge slurries from different tanks that has been or will be qualified before being transferred to DWPF. As a part of the Sludge Batch 3 (SB3) qualification task, rheology measurements of the sludge slurry were requested at different insoluble solids loadings. These measurements were requested in order to gain insight into potential processing problems that may occur as the insoluble solids are adjusted up or down (by concentration or dilution) during the process. As a part of this study, a portion of the ''as received'' SB3 sample was washed with inhibited water (0.015 M NaOH and 0.015 M NaNO2) to target 0.5M Na versus a measured 1M Na in the supernate. The purpose of the ''washing'' step was to allow a comparison of the SB3 rheological data to the rheological data collected for Sludge Batch 2 (SB2) and to determine if there was a dependence of the yield stress and consistency as a function of washing. The ''as received'' SB3 rheology data was also compared to SB3 simulants prepared by the Simulant Development Program in order to provide guidance for selecting a simulant that is more representative of the rheological properties of the radioactive sludge slurry. A summary of the observations, conclusions are: (1) The yield stress and plastic viscosity increased as the weight percent insoluble solids were increased for the ''as received'' and ''washed'' SB3 samples, at a fixed pH. (2) For the same insoluble solids loading, the yield stress for the SB2 sample is approximately a factor of three higher than the ''as received'' SB3 sample. There also appears to be small

Thermogravimetric analysis of the co-pyrolysis of paper sludge and municipal solid waste

International Nuclear Information System (INIS)

Fang, Shiwen; Yu, Zhaosheng; Lin, Yousheng; Hu, Shanchao; Liao, Yanfen; Ma, Xiaoqian

2015-01-01

Highlights: • The co-pyrolysis of municipal solid waste, paper sludge and the blends was studied. • The reactivity of paper sludge could be improved by blending municipal solid waste. • The FWO and KAS methods were used to calculate activation energy. • The average activation energy was the minimum by blending 50% paper sludge. - Abstract: The pyrolysis characteristics of municipal solid waste (MSW), paper sludge (PS) and their blends were studied through a thermogravimetric simultaneous thermal analyzer from room temperature to 1000 °C. Meanwhile their kinetics were studied by Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. The mass proportions of PS in the blends were 10%, 30%, 50%, 70%, 90%, respectively and the experiments were carried out at different heating rates (30, 40 and 50 °C/min). The initial temperature of MSW was lower than that of PS and the terminated temperature was higher than PS. The comprehensive characteristic index decreased progressively along with the decrease of the MSW proportion. The values of average activation energies calculated by FWO and KAS methods were highly consistent. The average activation energy reached the minimum number, 96.7 kJ/mol by KAS and 11.56 kJ/mol by FWO, with the proportion of PS was 50%

Keynote address: Federal overview of municipal sludge management

International Nuclear Information System (INIS)

Hathaway, W.B.

1979-01-01

The proper disposal of sewage sludge is becoming an increasing problem on solid waste management systems throughout the country. Currently 18,000 municipal wastewater treatment plants are generating about 5 million tons of sludge a year. This is expected to double in the next 8 to 10 years. The environmental aspects of sludge disposal are discussed

Sampling of tar from sewage sludge gasification using solid phase adsorption.

Science.gov (United States)

Ortiz González, Isabel; Pérez Pastor, Rosa Ma; Sánchez Hervás, José Ma

2012-06-01

Sewage sludge is a residue from wastewater treatment plants which is considered to be harmful to the environment and all living organisms. Gasification technology is a potential source of renewable energy that converts the sewage sludge into gases that can be used to generate energy or as raw material in chemical synthesis processes. But tar produced during gasification is one of the problems for the implementation of the gasification technology. Tar can condense on pipes and filters and may cause blockage and corrosion in the engines and turbines. Consequently, to minimize tar content in syngas, the ability to quantify tar levels in process streams is essential. The aim of this work was to develop an accurate tar sampling and analysis methodology using solid phase adsorption (SPA) in order to apply it to tar sampling from sewage sludge gasification gases. Four types of commercial SPA cartridges have been tested to determine the most suitable one for the sampling of individual tar compounds in such streams. Afterwards, the capacity, breakthrough volume and sample stability of the Supelclean™ ENVI-Carb/NH(2), which is identified as the most suitable, have been determined. Basically, no significant influences from water, H(2)S or NH(3) were detected. The cartridge was used in sampling real samples, and comparable results were obtained with the present and traditional methods.

Mesophilic anaerobic co-digestion of municipal solid waste and sewage sludge

DEFF Research Database (Denmark)

Aghdam, Ehsan Fathi; Kinnunen, V.; Rintala, Jukka A.

2015-01-01

This paper presents mesophilic anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW), biowaste (BW), sewage sludge (SS), and co-digestion of BW and SS. Average methane yields of 386 ± 54, 385 ± 82, 198 ± 14, and 318 ± 59 L CH4/kg volatile solids (VS) were obtained for OFMSW...

Solidifying power station resins and sludges

International Nuclear Information System (INIS)

Willis, A.S.D.; Haigh, C.P.

1984-01-01

Radioactive ion exchange resins and sludges arise at nuclear power stations from various operations associated with effluent treatment and liquid waste management. As the result of an intensive development programme, the Central Electricity Generating Board (CEGB) has designed a process to convert power station resins and sludges into a shielded, packaged solid monolithic form suitable for final disposal. Research and development, the generic CEGB sludge/resin conditioning plant and the CEGB Active Waste Project are described. (U.K.)

Durability and Mechanical Performance of PMMA/Stone Sludge Nanocomposites for Acrylic Solid Surface Applications

Directory of Open Access Journals (Sweden)

Samah EL-Bashir

2017-11-01

Full Text Available Acrylic solid surface sheets were prepared by mixing different kinds of stone sludge fillers (SSF in Poly (methyl methacrylate (PMMA nanocomposites. PMMA nanocomposite syrups were made using free radical polymerization of methylmethacrylate (MMA, then two kinds of nanofillers were added, namely, hydrophilic nanosilica and clay Halloysite nanotubules (HNTs. Acrylic solid surface sheets were manufactured by mixing the syrups with SSFs. The morphology of the produced sheets was studied using optical, and Scanning Electron Microscopy (SEM that revealed the uniform distribution of stone sludge in the polymeric matrix. The study of the physical properties showed promising mechanical performance and durability of PMMA/SSF nanocomposites for acrylic solid surface applications.

Characterization and migration of oil and solids in oily sludge during centrifugation.

Science.gov (United States)

Wang, Jun; Han, Xu; Huang, Qunxing; Ma, Zengyi; Chi, Yong; Yan, Jianhua

2018-05-01

The migration behaviors of oil, water and solids in sludge during centrifugation were elaborated. Size distribution, surface topography and lypohydrophilic properties were studied in detail. The average size of solids was 61 μm in original sludge, 31 μm in upper layer and 235 μm in bottom layer. The result shows that solvent is essential to separate oil phase into molecular light and weight fractions during centrifugation. With solvent/oil ratio increases from 1:2, 1:1, 2:1 to 5:1, molecular weight in upper layer decreases from 1044, 1043, 1020 to 846 combined with that in bottom layer increases. A model was proposed to calculate the oil residue content in solid phases after sedimentation. The findings of this paper provide information for optimizing the oil recovery and clean treatment.

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.

Design of jet manipulator for sludge lancing for steam generators

International Nuclear Information System (INIS)

Kumar, Kundan; Nathani, D.K.; Kayal, J.N.; Rupani, B.B.

2006-01-01

The sludge accumulation in secondary side of mushroom type steam generators of Indian Pressurised Heavy Water Reactors (PHWRs) may lead to loss of thermal efficiency and corrosion. Sludge removal is required to minimise such effects for safe and enhanced operating life of the steam generators. A sludge lancing system has been developed for sludge removal from the secondary side of the steam generators. Jet Manipulator is one of the various modules of the sludge lancing system. The JM consists of three modules namely walker, elevator and nozzle heads. Each module is designed to pass through hand hole, having 180 mm diameter and 100 mm wide gap between steam generator shell and shroud. These three modules are connected to each other by quick connecting type joints and are having their specific functions. The walker crawls by step of single pitch of the tube along the central no-tube lane of the steam generator by taking lateral supports on the nearest tubes. The elevator is capable of lifting the nozzle head to a suitable height required for lancing operation of entire tube sheet of the steam generator. The nozzle head directs the multiple jets along the narrow inter tube lanes having 3 mm width, on both sides of the central no-tube lane. The nozzle can be set to move at different elevations such that the multiple jets will graze along the narrow tube lane to create the sludge lancing action. The provision exists for movement of JM in both directions, i.e. forward and reverse. This paper highlights the objective, design and development, selection of nozzles, qualification and performance evaluation of JM. The manipulator is remotely operable by compressed air in the forward and reverse direction in the central no-tube lane to position the nozzle head in the horizontal direction. (author)

Biological treatment of petroleum sludges in liquid/solids contact reactors

Energy Technology Data Exchange (ETDEWEB)

Stroo, H F [Remediation Technologies, Inc., Kent, WA (USA)

1989-10-01

Biological treatment of hazardous wastes (bioremediation) is now recognized as an effective and cost-efficient approach for on-site cleanup of petroleum-contaminated soils and sludges. These strategies may require pretreatment of oily sludges produced as refinery wastes. Recent work has shown that liquid/solids contact (LSC) bioreactors are capable of adequate pretreatment at lower cost than competing technologies. Since LSC operations aim to maximize microbial numbers and activity, inexpensive microbiological monitoring can provide rapid feedback on performance. LSC technology represents a method for rapid biological treatment of petroleum sludges in a contained reactor. The technology has proven highly effective for a variety of oil refinery sludges, with degradation rates up to ten times faster than those observed during land treatment. The most promising use of LSC is a pretreatment. Because biological treatment in LSC can degrade and detoxify contaminants rapidly and relatively inexpensively, with little risk of off-site contamination, this technology should be considered by refiners having to close sites or treat current waste-streams. 7 refs., 1 figs., 1 tab.

Improvement of sludge removal performance for steam generators

International Nuclear Information System (INIS)

Nishida, K.; Sakai, K.; Ito, H.; Tanahashi, A.; Nakao, F.

2002-01-01

Scale, mainly consisting of magnetite, flows on the secondary side of steam generators (SGs), causing the formation of concentrations of impurities on the tubesheet (TS), increasing the fouling of tube heat transfer, and blocking the broached egg crates (BEC) on the tube support plates (TSP). Accumulation of sludge on the tubesheet forms environment in which impurities are highly concentrated on the tubes. And we have experienced tube degradation, in the past, from the concentration of impurities. In Japan, the first tubesheet sludge lancing, via water jets, was done at the Mihama-2 plant in 1975. And that is why this pile sludge becomes hard depending on time, removal made an effort toward removal with CECIL* (in bundle cleaning system) us very difficulty. However, sludge remained in localized areas and it had possibility of concentration. So that we improve the CECIL for the purpose of removing it, and we improved removal performance of the device. In addition to the improvement of CECIL, we install a sludge collector in order to decrease accumulation of sludge on the tubesheet. This paper introduces these improvements in sludge removal performance. (authors)

Free nitrous acid pre-treatment of waste activated sludge enhances volatile solids destruction and improves sludge dewaterability in continuous anaerobic digestion.

Science.gov (United States)

Wei, Wei; Wang, Qilin; Zhang, Liguo; Laloo, Andrew; Duan, Haoran; Batstone, Damien J; Yuan, Zhiguo

2018-03-01

Previous work has demonstrated that pre-treatment of waste activated sludge (WAS) with free nitrous acid (FNA i.e. HNO 2 ) enhances the biodegradability of WAS, identified by a 20-50% increase in specific methane production in biochemical methane potential (BMP) tests. This suggests that FNA pre-treatment would enhance the destruction of volatile solids (VS) in an anaerobic sludge digester, and reduce overall sludge disposal costs, provided that the dewaterability of the digested sludge is not negatively affected. This study experimentally evaluates the impact of FNA pre-treatment on the VS destruction in anaerobic sludge digestion and on the dewaterability of digested sludge, using continuously operated bench-scale anaerobic digesters. Pre-treatment of full-scale WAS for 24 h at an FNA concentration of 1.8 mg NN/L enhanced VS destruction by 17 ± 1% (from 29.2 ± 0.9% to 34.2 ± 1.1%) and increased dewaterability (centrifuge test) from 12.4 ± 0.4% to 14.1 ± 0.4%. Supporting the VS destruction data, methane production increased by 16 ± 1%. Biochemical methane potential tests indicated that the final digestate stability was also improved with a lower potential from FNA treated digestate. Further, a 2.1 ± 0.2 log improvement in pathogen reduction was also achieved. With inorganic solids representing 15-22% of the full-scale WAS used, FNA pre-treatment resulted in a 16-17% reduction in the volume of dewatered sludge for final disposal. This results in significantly reduced costs as assessed by economic analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design of segmental ultrasonic cleaning equipment for removing the sludge in a steam generator

International Nuclear Information System (INIS)

Kim, Seok Tae; Jeong, Woo Tae; Byeon, Min Suk; Lee, Ho One

2010-01-01

In nuclear power plants, the water in the coolant system is managed to be clean but metallic sludge is accumulated on the top of tube-sheet in a steam generator. The sludge causes the corrosion of the tubesheet. The electric utility company in Korea removes the sludge with a lancing system for every outage of nuclear power plants. But the sludge is not perfectly removed with lancing system because the pressurized water of the lancing system cannot reach all area in a steam generator. Therefore the steam generator cleaning system with ultrasonic energy has been developed in KEPCO Research Institute. In this paper, the ultrasonic cleaning system is designed for removing the sludge on the steam generator

A review on paint sludge from automotive industries: Generation, characteristics and management.

Science.gov (United States)

Salihoglu, Guray; Salihoglu, Nezih Kamil

2016-03-15

The automotive manufacturing process results in the consumption of several natural sources and the generation of various types of wastes. The primary source of hazardous wastes at an automotive manufacturing plant is the painting process, and the major waste fraction is paint sludge, which is classified with EU waste code of 080113* implying hazardous characteristics. The amount of the paint sludge generated increases every year with the worldwide increase in the car production. The characteristics of the paint sludge, which mainly designate the management route, are mainly determined by the type of the paint used, application technique employed, and the chemicals applied such as flocculants, detackifiers, pH boosters, antifoam agents, and biocides as well as the dewatering techniques preferred. Major routes for the disposal of the paint sludges are incineration as hazardous waste or combustion at cement kilns. Because of high dissolved organic carbon content of the paint, the paint sludge cannot be accepted by landfills according to European Union Legislations. More investigations are needed in the field of paint sludge recycling such as recycling it as a new paint or as other formulations, or making use of the sludge for the production of construction materials. Research on the applicability of the paint sludge in composting and biogasification can also be useful. Ongoing research is currently being conducted on new application techniques to increase the effectiveness of paint transfer, which helps to prevent the generation of paint sludge. Advancements in paint and coating chemistry such as the reduction in the coating layers with its thickness also help to decrease the level of paint sludge generation. Investigations on the effects of the chemicals on the recycling potential of paint sludges and consideration of these effects by the chemical manufacturer companies would be extremely important. This review presents the formation of paint sludge, the factors

Sludge cleaning in the steam generators: sludge Lancing e IBL

International Nuclear Information System (INIS)

Montoro, E.; Gonzalez, S.; Calderon, N.

2013-01-01

IBERDROLA Engineering and Construction has echoed the need for plants to remove oxide deposits (sludge) located on the secondary side, on the bottom plate and into the tube bundle steam steam generators. Therefore, and with its partner SAVAC SRA has developed a specific system consisting of applying a capillary water at very high pressure applied directly to the location of these oxides. (Author)

Continues treatment of oily sludge at Colombian refineries

International Nuclear Information System (INIS)

Echeverria, Victor; Monsalve, Gladys; Vidales, Humberto

2002-01-01

The Colombian Petroleum institute - ICP, the research and development branch of Ecopetrol has developed a unique technological package used to treat oily sludge in a continuous way. The sludge comes from a refinery with 220000 barrels of crude per day load, located in the Middle Madgalena River Valley in Colombia. The technological package allows for a) the recovery of the hydrocarbon contained in oily wastes (up to 50%) b) the elimination of the oil contained in solid using a biodegradation process and, c) the availability economically and technically feasible solution to handle oily sludge generated in the refinery. The oily treated in this process come from maintenance of refinery's equipment and also from the physical chemical separation process at the industrial wastewater treatment plant. Oily sludge is a complex system where light and heavy oils, contaminated water and contaminated solids coexist in the form of direct, inverse and multiple emulsions. The comprehensive technological package allows the treatment of oily sludge in a cost effective way. ICP technological package developed includes technologies combining mechanical, thermal, chemical and electrostatic dehydration techniques and stimulated and intensive bioremediation to decontamination of solids saturated with residual oil. This technological package brings a solution to old environmental problem caused by the inappropriate final disposal of oily wastes such as storage in ponds, marshes and open pits: Nowadays wastes generated are treated in a continuous process that is environmentally friendly and economically profitable

pH neutralization of the by-product sludge waste water generated from waste concrete recycling process using the carbon mineralization

Science.gov (United States)

Ji, Sangwoo; Shin, Hee-young; Bang, Jun Hwan; Ahn, Ji-Whan

2017-04-01

About 44 Mt/year of waste concrete is generated in South Korea. More than 95% of this waste concrete is recycled. In the process of regenerating and recycling pulmonary concrete, sludge mixed with fine powder generated during repeated pulverization process and water used for washing the surface and water used for impurity separation occurs. In this way, the solid matter contained in the sludge as a by-product is about 40% of the waste concrete that was input. Due to the cement component embedded in the concrete, the sludge supernatant is very strong alkaline (pH about 12). And it is necessary to neutralization for comply with environmental standards. In this study, carbon mineralization method was applied as a method to neutralize the pH of highly alkaline waste water to under pH 8.5, which is the water quality standard of discharged water. CO2 gas (purity 99%, flow rate 10ml/min.) was injected and reacted with the waste water (Ca concentration about 750mg/L) from which solid matter was removed. As a result of the experiment, the pH converged to about 6.5 within 50 minutes of reaction. The precipitate showed high whiteness. XRD and SEM analysis showed that it was high purity CaCO3. For the application to industry, it is needed further study using lower concentration CO2 gas (about 14%) which generated from power plant.

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

Science.gov (United States)

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

2014-01-01

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

Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

Science.gov (United States)

Ge, Huoqing; Batstone, Damien; Keller, Jurg

2016-01-01

The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

Characterization of sewage sludge generated in Rio de Janeiro, Brazil, and perspectives for agricultural recycling

Directory of Open Access Journals (Sweden)

Alan Henrique Marques de Abreu

2017-08-01

Full Text Available Sanitary sewage collection and treatment is a serious environmental problem in Brazilian cities, as well as the destination of solid waste resulting from this process, i.e. the sewage sludge, a substance rich in organic matter and nutrients, which is normally discarded in landfills. The aim of this study was to characterize the sewage sludge generated in four treatment stations in Rio de Janeiro State, Brazil and check if they meet the legal criteria of the National Environment Council (CONAMA, Resolution No. 375/2006. It also focused on analyzing the perspectives for its agricultural recycling based on the potential demand for main agricultural crops grown in Rio de Janeiro State. Samples from eight sewage sludge lots from four treatment stations located in the metropolitan area of Rio de Janeiro were analyzed. These stations receive and treat only domestic sewage by activated sludge system. For chemical and biological characterization of these lots, representative samples were collected and analyzed according to parameters of CONAMA Resolution No. 375/2006. In order to analyze the perspectives of agricultural recycling of sewage sludge in Rio de Janeiro State, 10 crops with the largest cultivated area in the state were surveyed and analyzed which of them are apt to receive sewage sludge as fertilizer and/or soil amendment. To determine the potential demand for sewage sludge in agriculture, the area occupied by these crops were multiplied by each fertilizer recommendation considering the sewage sludge as fertilizer. The analyzed sludge presented a high content of nutrients and organic matter and was included in the parameters of heavy metals, pathogenic agents, and bacteriological indicators stipulated by CONAMA Resolution No. 375/2006. The agricultural panorama of Rio de Janeiro State is favorable for agricultural recycling of sewage sludge since there is a great potential demand for this residue and, among the 10 agricultural crops with the

Investigations on generation and use of a sludge-lime fertilizer. Untersuchungen zur Erzeugung und Anwendung eines Klaerschlamm-Kalkduengers

Energy Technology Data Exchange (ETDEWEB)

Boehnke, B; Weiling, R

1980-06-01

Sludge is an important energy and raw material source, which if possible should be utilized in agriculture. Through the addition of unslaked lime a hygienically safe product can be prepared with the help of a suitable treatment process and can be offered in granulated form as a valuable sludge-lime fertilizer. Sludges of different consistencies and origins were investigated. Varying amounts and types of lime were used and the products were tested for easy handling, storage capability and temperature influence on the hygienic conditions. In order to obtain a disseminable substance, a solid matter content of over 60% is necessary. This is achieved through variation of the lime content depending on the solid content of the respective sludge. According to the existing regulations, which fix the minimum CaO content in a lime fertilizer at 30%, a predewatering of the sludge up to 25%-30% of the solid matter content is sufficient. Economic viability is assured, specially in areas where intensive agricultural use of lime fertilizer is necessary. (orig.) With 32 refs., 15 tabs., 27 figs.

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

Effect of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions.

Science.gov (United States)

Diak, James; Örmeci, Banu; Kennedy, Kevin J

2013-04-01

Micro-aeration, which refers to the addition of very small amounts of air, is a simple technology that can potentially be incorporated in septic tanks to improve the digestion performance. The purpose of this study was to investigate and compare the effects of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions. 1.6 L batch reactor experiments were carried out in duplicate using raw primary sludge, with 4.1 % total solids, and diluted primary sludge, with 2.1 % total solids. Reactors were operated for 5 weeks at room temperature to simulate septic tank conditions. Micro-aeration rate of 0.00156 vvm effectively solubilised chemical oxygen demand (COD) and improved the subsequent degradation of COD. Micro-aeration also increased the generation of ammonia and soluble proteins, but did not improve the reduction in total and volatile solids, or the reduction in carbohydrates. Experiments using diluted sludge samples showed similar trends as the experiments with raw sludge, which suggest that initial solids concentration did not have a significant effect on the degradation of primary sludge under septic tank conditions.

Potential Application of Ganoderma lucidum in Solid State Fermentation of Primary Sludge and Wheat Straw

Directory of Open Access Journals (Sweden)

João Paulo Furlan de Jesus

2015-04-01

Full Text Available This study was conducted to investigate the production of lignocellulolytic enzymes and sugars by the fungus Ganoderma lucidum during solid state fermentation (SSF using primary sludge (PS and wheat straw (WS as substrates at different concentration ratios. For fungal growth on SSF, 20 g of each blended substrate was added to Erlenmeyer flasks, which were autoclaved and maintained at room temperature prior to inoculation, whereas for submerged fermentation (SF, flasks containing 25 mL of potato dextrose broth (PDB were used as standard to check the differences between both methods of growth, and then all flasks were incubated at 25 °C in the dark, during 8 and 16 days. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis from the protein extract obtained from solid state fermentation strongly suggested that G. lucidum could produce lignocellulolytic enzymes to degrade primary sludge and wheat straw. Among the sugars, the production of xylose and mannose was disturbed by adding primary sludge. With the addition of primary sludge, high glucuronic acid content was observed. The results suggest that the combination of primary sludge and wheat straw, at concentration ratios of 1:1 to 1:3, respectively, can be used as a raw material in the production of lignocellulolytic enzymes and the bioconversion of other types of biomass by G. lucidum.

Hard sludge formation in modern steam generators of nuclear power plants. Formation, risks and mitigation

International Nuclear Information System (INIS)

Strohmer, F.

2014-01-01

In recent years modern steam generators with triangular pitch tube bundle geometry have experienced damage caused by hard sludge formation on top of the tube sheet and denting. The effect can lead to a limitation of the modern steam generators’ lifetime. The current publication shows reasons for the generation of hard sludge formation. Moreover, it describes the risk arising from hard sludge formation for the concerned steam generators and the mitigation of the problem. The main factors contributing to the formation of hard sludge are: the amount of corrosion product ingress into the steam generators, hard sludge formation favouring impurities and, skipped maintenance applications during outages. The main damaging mechanism of denting that can arise under certain secondary side conditions from hard sludge is explained. For steam generator tube denting, aggressive, oxidizing conditions have to be established in crevices beneath the hard sludge piles. Severely dented tubes are sensitive toward outer diameter stress corrosion cracking (ODSCC). The denting and ODSCC mechanism is explained. In addition, a proactive long-term maintenance strategy to avoid the formation of hard sludge piles will be shown. The strategy is based on a reduction of the corrosion product ingress into the steam generator's secondary side, and on the regular removal of deposits from the tube sheet and from the entire upper bundle area by latest mechanical cleaning methods. For hard deposits - formed either by silicates or long term hardened corrosion products, which, in the past, could not be removed by chemical or mechanical means - a new, simple, mechanical cleaning method is presented. This method can be used during the normal time frame of an outage and allows the restart of the unit with clean steam generator tube sheets. This mitigates the tendency to form hard sludge and denting in the long term. (author)

Parametric effect during power generation from sewage sludge using prototype mfc

International Nuclear Information System (INIS)

Memon, A.R.; Aftab, A.

2015-01-01

Pakistan like other countries is also faced with energy crisis, for which there is a need to identify indigenous technologies along with renewable energy sources to satisfy the energy footprint of the country. Use of MFC (Microbial Fuel Cell) technique is currently a step towards this direction that can play an effective role in solving the dual problems of environmental pollution and energy shortage. In this study, sewage sludge from a wastewater treatment plant was collected and used as a substrate for electricity generation in association with other biomass sources. Effect of relevant parameters such as oxygen flow rate, pH and concentration on voltage generation was also analyzed. The experimental results yielded in voltage generation of 2500 mv/l for sewage sludge in comparison to that obtained using carbon manure (270 mv/l), wastewater (229 mv/l) and cow manure (330 mv/l) suggesting towards the potential of sewage sludge for power generation. (author)

Characteristics of sustainable bio-solid fuel produced from sewage sludge as a conventional fuel substitute

International Nuclear Information System (INIS)

Jung, Bongjin; Nam, Wonjun; Lee, Na-Yeon; Kim, Kyung-Hoon

2010-01-01

Safely final disposal of sewage sludge which is being increased every year has already become serious problems. As one of the promising technologies to solve this problem, thermal drying method has been attracting wide attention due to energy recovery from sewage sludge. This paper describes several characteristics of sustainable bio-solid fuel, as a conventional fuel substitute, produced from sewage sludge drying and granulation plant having the treatment capacity of 10 ton/ day. This plant has been successfully operated many times and is now designing for scale-up. Average moisture content of twelve kinds of bio-solid fuels produced from the plant normally less than 10 wt% and average shape of them is mainly composed of granular type having a diameter of 2-8 mm for easy handling and transportation to the final market destinations. Average higher heating value, which is one of the important properties to estimate the possibility of available energy, of bio-solid fuels is about 3800 kcal/ kg as dry basis. So they can be utilized to supply energy in the coal power plant and cement kiln etc. as a conventional fuel substitute for a beneficial reuse. Characteristics including proximate analysis, ultimate analysis, contents of heavy metals, wettability etc. of bio-solid fuels have been also analyzed for the environmentally safe re utilization. (author)

The effect of mixing ratio variation of sludge and organic solid waste on biodrying process

Science.gov (United States)

Nasution, A. C.; Kristanto, G. A.

2018-01-01

In this study, organic waste was co-biodried with sludge cake to determine which mixing ratio gave the best result. The organic waste was consisted of dried leaves and green leaves, while the sludge cake was obtained from a waste water treatment plant in Bekasi. The experiment was performed on 3 lab-scale reactors with same specifications. After 21 days of experiment, it was found that the reactor with the lowest mixing fraction of sludge (5:1) has the best temperature profile and highest moisture content depletion compared with others. Initial moisture content and initial volatile solid content of this reactor’s feedstock was 52.25% and 82.4% respectively. The airflow rate was 10 lpm. After biodrying was done, the final moisture content of the feedstock from Reactor C was 22.0% and the final volatile solid content was 75.9%.The final calorific value after biodrying process was 3179,28kcal/kg.

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.

Mitigation of Hydrogen Gas Generation from the Reaction of Uranium Metal with Water in K Basin Sludge and Sludge Waste Forms

Energy Technology Data Exchange (ETDEWEB)

Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

2011-06-08

Prior laboratory testing identified sodium nitrate and nitrite to be the most promising agents to minimize hydrogen generation from uranium metal aqueous corrosion in Hanford Site K Basin sludge. Of the two, nitrate was determined to be better because of higher chemical capacity, lower toxicity, more reliable efficacy, and fewer side reactions than nitrite. The present lab tests were run to determine if nitrate’s beneficial effects to lower H2 generation in simulated and genuine sludge continued for simulated sludge mixed with agents to immobilize water to help meet the Waste Isolation Pilot Plant (WIPP) waste acceptance drainable liquid criterion. Tests were run at ~60°C, 80°C, and 95°C using near spherical high-purity uranium metal beads and simulated sludge to emulate uranium-rich KW containerized sludge currently residing in engineered containers KW-210 and KW-220. Immobilization agents tested were Portland cement (PC), a commercial blend of PC with sepiolite clay (Aquaset II H), granulated sepiolite clay (Aquaset II G), and sepiolite clay powder (Aquaset II). In all cases except tests with Aquaset II G, the simulated sludge was mixed intimately with the immobilization agent before testing commenced. For the granulated Aquaset II G clay was added to the top of the settled sludge/solution mixture according to manufacturer application directions. The gas volumes and compositions, uranium metal corrosion mass losses, and nitrite, ammonia, and hydroxide concentrations in the interstitial solutions were measured. Uranium metal corrosion rates were compared with rates forecast from the known uranium metal anoxic water corrosion rate law. The ratios of the forecast to the observed rates were calculated to find the corrosion rate attenuation factors. Hydrogen quantities also were measured and compared with quantities expected based on non-attenuated H2 generation at the full forecast anoxic corrosion rate to arrive at H2 attenuation factors. The uranium metal

Mitigation of Hydrogen Gas Generation from the Reaction of Uranium Metal with Water in K Basin Sludge and Sludge Waste Forms

International Nuclear Information System (INIS)

Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

2011-01-01

Prior laboratory testing identified sodium nitrate and nitrite to be the most promising agents to minimize hydrogen generation from uranium metal aqueous corrosion in Hanford Site K Basin sludge. Of the two, nitrate was determined to be better because of higher chemical capacity, lower toxicity, more reliable efficacy, and fewer side reactions than nitrite. The present lab tests were run to determine if nitrate's beneficial effects to lower H2 generation in simulated and genuine sludge continued for simulated sludge mixed with agents to immobilize water to help meet the Waste Isolation Pilot Plant (WIPP) waste acceptance drainable liquid criterion. Tests were run at ∼60 C, 80 C, and 95 C using near spherical high-purity uranium metal beads and simulated sludge to emulate uranium-rich KW containerized sludge currently residing in engineered containers KW-210 and KW-220. Immobilization agents tested were Portland cement (PC), a commercial blend of PC with sepiolite clay (Aquaset II H), granulated sepiolite clay (Aquaset II G), and sepiolite clay powder (Aquaset II). In all cases except tests with Aquaset II G, the simulated sludge was mixed intimately with the immobilization agent before testing commenced. For the granulated Aquaset II G clay was added to the top of the settled sludge/solution mixture according to manufacturer application directions. The gas volumes and compositions, uranium metal corrosion mass losses, and nitrite, ammonia, and hydroxide concentrations in the interstitial solutions were measured. Uranium metal corrosion rates were compared with rates forecast from the known uranium metal anoxic water corrosion rate law. The ratios of the forecast to the observed rates were calculated to find the corrosion rate attenuation factors. Hydrogen quantities also were measured and compared with quantities expected based on non-attenuated H2 generation at the full forecast anoxic corrosion rate to arrive at H2 attenuation factors. The uranium metal

Influence of organic loading rate on methane production in a CSTR from physicochemical sludge generated in a poultry slaughterhouse.

Science.gov (United States)

López-Escobar, Luis A; Martínez-Hernández, Sergio; Corte-Cano, Grisel; Méndez-Contreras, Juan M

2014-01-01

The influence of the increase of the organic loading rate (OLR) on methane production in a continuous stirred-tank reactor (CSTR) from physicochemical sludge generated in a poultry slaughterhouse was evaluated. Total solid (TS) to obtain OLR of 1, 5, 10 and 15 g VS L(-1) day(-1), with hydraulic retention times of 29, 6, 6 and 4, respectively, were conditioned. The results showed a decrease in pH levels and an increase in the theoretical volatile fatty acids (VFA). While the yield of methane production decreased from 0.48 to 0.10 LCH4/g VSremoved, respectively, the OLR-10 managed on average 38% removal of volatile solids (VS) and a yield biogas production of 0.81 Lbiogas g(-1) VSremoved and 1.35 L day(-1). This suggests that the OLR increases in an anaerobic system from physicochemical sludge only inhibits the methanogenic metabolism, because there is still substrate consumption and biogas production.

Design, implementation and functional aspects of the control and instrumentation systems of computerised remote operated sludge lancing equipment

International Nuclear Information System (INIS)

Aparna, J.; Mehra, K.S.; Sharma, B.S.V.G.; Mohan, L.R.

2005-01-01

The computerised and remote operated sludge lancing equipment (SLE) uses high velocity narrow water jets for dislodging and removal of hard and strongly adhesive sludge from the secondary side tube sheet of mushroom type steam generators of Indian PHWRs. During the years of plant operation, corrosion products and other solids deposit in the form of sludge on the tube sheet of steam generators. The sludge formation not only affects adversely the steam generator performance but also diminishes its service life if left unchecked

Recent development in the treatment of oily sludge from petroleum industry: a review.

Science.gov (United States)

Hu, Guangji; Li, Jianbing; Zeng, Guangming

2013-10-15

Oily sludge is one of the most significant solid wastes generated in the petroleum industry. It is a complex emulsion of various petroleum hydrocarbons (PHCs), water, heavy metals, and solid particles. Due to its hazardous nature and increased generation quantities around the world, the effective treatment of oily sludge has attracted widespread attention. In this review, the origin, characteristics, and environmental impacts of oily sludge were introduced. Many methods have been investigated for dealing with PHCs in oily sludge either through oil recovery or sludge disposal, but little attention has been paid to handle its various heavy metals. These methods were discussed by dividing them into oil recovery and sludge disposal approaches. It was recognized that no single specific process can be considered as a panacea since each method is associated with different advantages and limitations. Future efforts should focus on the improvement of current technologies and the combination of oil recovery with sludge disposal in order to comply with both resource reuse recommendations and environmental regulations. The comprehensive examination of oily sludge treatment methods will help researchers and practitioners to have a good understanding of both recent developments and future research directions. Copyright © 2013 Elsevier B.V. All rights reserved.

Sludge quantification at water treatment plant and its management scenario.

Science.gov (United States)

Ahmad, Tarique; Ahmad, Kafeel; Alam, Mehtab

2017-08-15

Large volume of sludge is generated at the water treatment plants during the purification of surface water for potable supplies. Handling and disposal of sludge require careful attention from civic bodies, plant operators, and environmentalists. Quantification of the sludge produced at the treatment plants is important to develop suitable management strategies for its economical and environment friendly disposal. Present study deals with the quantification of sludge using empirical relation between turbidity, suspended solids, and coagulant dosing. Seasonal variation has significant effect on the raw water quality received at the water treatment plants so forth sludge generation also varies. Yearly production of the sludge in a water treatment plant at Ghaziabad, India, is estimated to be 29,700 ton. Sustainable disposal of such a quantity of sludge is a challenging task under stringent environmental legislation. Several beneficial reuses of sludge in civil engineering and constructional work have been identified globally such as raw material in manufacturing cement, bricks, and artificial aggregates, as cementitious material, and sand substitute in preparing concrete and mortar. About 54 to 60% sand, 24 to 28% silt, and 16% clay constitute the sludge generated at the water treatment plant under investigation. Characteristics of the sludge are found suitable for its potential utilization as locally available construction material for safe disposal. An overview of the sustainable management scenario involving beneficial reuses of the sludge has also been presented.

Simulation of co-incineration of sewage sludge with municipal solid waste in a grate furnace incinerator.

Science.gov (United States)

Lin, Hai; Ma, Xiaoqian

2012-03-01

Incineration is one of the most important methods in the resource recovery disposal of sewage sludge. The combustion characteristics of sewage sludge and an increasing number of municipal solid waste (MSW) incineration plants provide the possibility of co-incineration of sludge with MSW. Computational fluid dynamics (CFD) analysis was used to verify the feasibility of co-incineration of sludge with MSW, and predict the effect of co-incineration. In this study, wet sludge and semi-dried sludge were separately blended with MSW as mixed fuels, which were at a co-incineration ratios of 5 wt.% (wet basis, the same below), 10 wt.%, 15 wt.%, 20 wt.% and 25 wt.%. The result indicates that co-incineration of 10 wt.% wet sludge with MSW can ensure the furnace temperature, the residence time and other vital items in allowable level, while 20 wt.% of semi-dried sludge can reach the same standards. With lower moisture content and higher low heating value (LHV), semi-dried sludge can be more appropriate in co-incineration with MSW in a grate furnace incinerator. Copyright © 2011 Elsevier Ltd. All rights reserved.

Rheology of Savannah River site tank 42 and tank 51 HLW radioactive sludges

International Nuclear Information System (INIS)

Ha, B.C.; Bibler, N.E.

1996-01-01

Knowledge of the rheology of the radioactive sludge slurries at the Savannah River Site (SRS) is necessary in order to ensure that they can be retrieved from waste tanks and processed for final disposal. The high activity radioactive wastes stored as caustic slurries at SRS result from the neutralization of acid waste generated from production of nuclear defense materials. During storage, the wastes separate into a supernate layer and a sludge layer. In the Defense Waste Processing Facility (DWPF) at SRS, the radionuclides from the sludge and supernate will be immobilized into borosilicate glass for long term storage and eventual disposal. Before transferring the waste from a storage tank to the DWPF, a portion of the aluminum in the waste sludge will be dissolved and the sludge will be extensively washed to remove sodium. Tank 51 and Tank 42 radioactive sludges represent the first batch of HLW sludge to be processed in the DWPF. This paper presents results of rheology measurements of Tank 51 and Tank 42 at various solids concentrations. The rheologies of Tank 51 and Tank 42 radioactive slurries were measured remotely in the Shielded Cells Operations (SCO) at the Savannah River Technology Center (SRTC) using a modified Haake Rotovisco RV-12 with an M150 measuring drive unit and TI sensor system. Rheological properties of the Tank 51 and Tank 42 radioactive sludges were measured as a function of weight percent solids. The weight percent solids of Tank 42 sludge was 27, as received. Tank 51 sludge had already been washed. The weight percent solids were adjusted by dilution with water or by concentration through drying. At 12, 15, and 18 weight percent solids, the yield stresses of Tank 51 sludge were 5, 11, and 14 dynes/cm2, respectively. The apparent viscosities were 6, 10, and 12 centipoises at 300 sec-1 shear rate, respectively

Evaluation of sludge pile formation in a U-tube steam generator using a scale model

International Nuclear Information System (INIS)

Padmanabhan, M.; LeClair, M.L.; Chandra, S.; Grondahl, E.E.

1989-01-01

An experimental study was conducted to investigate sludge deposition in steam generators using a semicircular model to a geometric scale of 1:3 simulating the bottom region of a U-Tube steam generator. The vertical and horizontal velocity distributions and turbulence intensities at different elevations in the bottom region were measured using a Laser Doppler Anemometry (LDA) system. The sludge deposition tests were conducted using a sludge material selected after several trial tests with different materials. The deposition patterns showed good agreement with prototype sludge patterns, available from field data. A good correlation of the sludge deposition patterns with the measured flow patterns was established. Deposition of sludge was found to be initiated within the wakes behind the tubes. (orig./DG)

Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids.

Science.gov (United States)

Wang, Xiao; Duan, Xu; Chen, Jianguang; Fang, Kuo; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi

2016-01-01

In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production.

Analysis of petroleum oily sludge producing in petroleum field of Rio Grande do Norte, Brazil

Energy Technology Data Exchange (ETDEWEB)

Lima, Cicero de Souza; Lima, Regineide Oliveira; Silva, Edjane Fabiula Buriti da; Castro, Kesia Kelly Vieira de; Chiavone Filho, Osvaldo; Araujo, Antonio Souza de [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil)

2012-07-01

In exploration and production of petroleum is generated solid waste different and components other. The petroleum oily sludge is a complex mix of components different (water, oil and solid). The petroleum oily sludge generally has other residues and is formed during production and operations, transport, storage and petroleum refining (atmospheric residue, vacuum residue and catalytic cracking residue). However, according to its origin, the compositions can be found quite varied for sludge. Observing the process steps production and refining is possible to locate its main sources and percentage contributions in terms of waste generation. The elemental analysis was performed with oily sludge from region and it showed different composition. For carbon element and hydrogen, small differences was observed, but for was observed greater differences for Oxygen element. The sludge has different inorganic and organic composition. The sludge from oil water separator (OWS) 2 showed a greater amount of oil (94.88%), this may indicate a residue of aggregate high for petroleum industry. In analysis of Saturates, Aromatics, Resins and Asphaltenes (SARA), the sludge from unloading showed amount high of saturates. The inorganic material separated from sludge was characterized and sludge from OWS 2 had high amount sulfur (41.57%). The sludge analyzed showed organic components high values, so it can be treated and reprocessed in process units petroleum industry. The analysis thermal degradation had a better setting for treated oily sludge. (author)

Analytical methodologies based on LC-MS/MS for monitoring selected emerging compounds in liquid and solid phases of the sewage sludge.

Science.gov (United States)

Boix, C; Ibáñez, M; Fabregat-Safont, D; Morales, E; Pastor, L; Sancho, J V; Sánchez-Ramírez, J E; Hernández, F

2016-01-01

In this work, two analytical methodologies based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) were developed for quantification of emerging pollutants identified in sewage sludge after a previous wide-scope screening. The target list included 13 emerging contaminants (EC): thiabendazole, acesulfame, fenofibric acid, valsartan, irbesartan, salicylic acid, diclofenac, carbamazepine, 4-aminoantipyrine (4-AA), 4-acetyl aminoantipyrine (4-AAA), 4-formyl aminoantipyrine (4-FAA), venlafaxine and benzoylecgonine. The aqueous and solid phases of the sewage sludge were analyzed making use of Solid-Phase Extraction (SPE) and UltraSonic Extraction (USE) for sample treatment, respectively. The methods were validated at three concentration levels: 0.2, 2 and 20 μg L(-1) for the aqueous phase, and 50, 500 and 2000 μg kg(-1) for the solid phase of the sludge. In general, the method was satisfactorily validated, showing good recoveries (70-120%) and precision (RSD metabolites of dipyrone had not been studied before in sewage sludge.

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)

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)

Anaerobic treatment of complex wastewater and waste activated sludge - Appl. of an upflow anaerobic solid removal (UASR).

NARCIS (Netherlands)

Zeeman, G.; Sanders, W.T.M.; Wang, K.Y.; Lettinga, G.

1997-01-01

The application of one phase anaerobic wastewater systems for the treatment of complex wastewaters containing high amounts of suspended solids or lipids is usually limited by accumulation of these compounds in the sludge bed. This accumulation reduces the solid retention time and methanogenic

Investigation of Rheological Impacts on the Defense Waste Processing Facility's Sludge Slurry Feed as Insoluble Solids and Wash Endpoints are Adjusted

International Nuclear Information System (INIS)

Fellinger, T. L.; Howard, S.J.; Lee, M.C.; Galloway, R.H.

2006-01-01

The Savannah River Site (SRS) is currently pursuing an aggressive program to empty its High Level Waste (HLW) tanks and immobilize its radioactive waste into a durable borosilicate glass in the Defense Waste Processing Facility (DWPF). To create a batch of feed for the DWPF, several tanks of radioactive sludge slurry are combined into one of the million gallon (i.e. 3.79 E06 liters) feed tanks for DWPF. Once these sludge slurries are combined, the soluble sodium and weight percent total solids are adjusted by a 'washing' process. The 'washing' process involves diluting the soluble sodium of the sludge slurry with inhibited water (0.015 M NaOH and 0.015 M NaNO 2 ) and allowing the sludge slurry to settle into two layers. The two layers in the tank consist of a clear supernate on top and a layer of settled sludge solids on the bottom. The clear supernate layer is then decanted to another hold tank. This 'washing' process is repeated until the desired wash endpoint (i.e. sodium concentration in the supernate) and weight percent total solids are achieved. A final washed batch of feed consists of approximately 500,000 gallons (i.e. 1.89 E06 liters). DWPF has already processed three batches of feed and is currently processing a fourth. Prior to processing a batch of feed in the DWPF, it must be well characterized. Samples of the prepared feed batch are sent to the Savannah River National Laboratory (SRNL) for this characterization. As a part of the SRNL characterization for the fourth batch, rheology measurements were performed. Measurements were performed at different weight percent insoluble solids loadings to mimic potential facility processing scenarios (i.e. mixing/pumping of concentrated sludge slurry). In order to determine the influence of the soluble Na on the rheological properties of the sample, the supernate of the 'as received' sample was adjusted from 1 M soluble Na to 0.5 M soluble Na by using a lab scale version of the 'washing' process. Rheology

A solid-phase extraction method for rapidly determining the adsorption coefficient of pharmaceuticals in sewage sludge

Science.gov (United States)

Berthod, Laurence; Roberts, Gary; Whitley, David C.; Sharpe, Alan; Mills, Graham A.

2014-01-01

The partitioning of pharmaceuticals in the environment can be assessed by measuring their adsorption coefficients (Kd) between aqueous and solid phases. Measuring this coefficient in sewage sludge gives an indication of their partitioning behaviour in a wastewater treatment plant and hence contributes to an understanding of their subsequent fate. The regulatory approved method for measuring Kd in sewage sludge is the US Environmental Protection Agency's Office of Prevention, Pesticides and Toxic Substances (OPPTS) guideline 835.1110, which is labour intensive and time consuming. We describe an alternative method for measuring the Kd of pharmaceuticals in sewage sludge using a modified solid-phase extraction (SPE) technique. SPE cartridges were packed at different sludge/PTFE ratios (0.4, 6.0, 24.0 and 40.0% w/w sludge) and eluted with phosphate buffer at pH 7.4. The approach was tested initially using three pharmaceuticals (clofibric acid, diclofenac and oxytetracycline) that covered a range of Kd values. Subsequently, the sorption behaviour of ten further pharmaceuticals with varying physico-chemical properties was evaluated. Results from the SPE method were comparable to those of the OPPTS test, with a correlation coefficient of 0.93 between the two approaches. SPE cartridges packed with sludge and PTFE were stable for up to one year; use within one month reduced variability in measurements (to a maximum of 0.6 log units). The SPE method is low-cost, easy to use and enables the rapid measurement of Kd values for a large number of chemicals. It can be used as an alternative to the more laborious full OPPTS test in environmental fate studies and risk assessments. PMID:25299795

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.

A study on torrefaction of sewage sludge to enhance solid fuel qualities

International Nuclear Information System (INIS)

Poudel, Jeeban; Ohm, Tae-In; Lee, Sang-Hoon; Oh, Sea Cheon

2015-01-01

Highlights: • The physio chemical variation of sewage sludge during torrefaction was studied. • Compounds with oxygen were emitted at a temperature lower than that for C x H y . • Sewage sludge torrefaction range was defined between 300 and 350 °C. - Abstract: Torrefaction is a treatment which serves to improve the properties of biomass in relation to thermochemical processing techniques for energy generation. In this study, the torrefaction of sewage sludge, which is a non-lignocellulosic waste was investigated in a horizontal tubular reactor under nitrogen flow at temperature ranging from 150 to 400 °C, for torrefaction residence time varying from 0 to 50 min. The torrefaction kinetics of sewage sludge was studied to obtain the kinetic parameters. The torrefied sewage sludge products were characterized in terms of their elemental composition, energy yield, ash content and volatile fraction. The energy and mass yields decreased with an increase in the torrefaction temperature. From an elemental analysis, the weight percentage of carbon in the sewage sludge increased with an increase in the torrefaction temperature. On the other hand, the weight percentages of hydrogen and oxygen tended to decrease. The gaseous products from torrefaction of sewage sludge were also analyzed. From this work, it was found that the compounds with oxygen were emitted at a temperature lower than that for hydrocarbon gases and the temperatures of 300–350 °C were the optimum torrefaction temperatures for sewage sludge

A study on torrefaction of sewage sludge to enhance solid fuel qualities

Energy Technology Data Exchange (ETDEWEB)

Poudel, Jeeban [Department of Mechanical Engineering, Kongju National University, 1223-24 Cheonan-Daero, Seobuk, Chungnam 330-717 (Korea, Republic of); Ohm, Tae-In [Department of Civil and Environmental Engineering, Hanbat National University, 125 Dongseo-Daero, Yuseong, Daejeon, 330-717 (Korea, Republic of); Lee, Sang-Hoon [Korea Institute of Energy Technology Evaluation and Planning, 135-502 Teheran-ro 114gil 14, Gangnam-gu, Seoul (Korea, Republic of); Oh, Sea Cheon, E-mail: ohsec@kongju.ac.kr [Department of Environmental Engineering, Kongju National University, 1223-24 Cheonan-Daero, Seobuk, Chungnam 330-717 (Korea, Republic of)

2015-06-15

Highlights: • The physio chemical variation of sewage sludge during torrefaction was studied. • Compounds with oxygen were emitted at a temperature lower than that for C{sub x}H{sub y}. • Sewage sludge torrefaction range was defined between 300 and 350 °C. - Abstract: Torrefaction is a treatment which serves to improve the properties of biomass in relation to thermochemical processing techniques for energy generation. In this study, the torrefaction of sewage sludge, which is a non-lignocellulosic waste was investigated in a horizontal tubular reactor under nitrogen flow at temperature ranging from 150 to 400 °C, for torrefaction residence time varying from 0 to 50 min. The torrefaction kinetics of sewage sludge was studied to obtain the kinetic parameters. The torrefied sewage sludge products were characterized in terms of their elemental composition, energy yield, ash content and volatile fraction. The energy and mass yields decreased with an increase in the torrefaction temperature. From an elemental analysis, the weight percentage of carbon in the sewage sludge increased with an increase in the torrefaction temperature. On the other hand, the weight percentages of hydrogen and oxygen tended to decrease. The gaseous products from torrefaction of sewage sludge were also analyzed. From this work, it was found that the compounds with oxygen were emitted at a temperature lower than that for hydrocarbon gases and the temperatures of 300–350 °C were the optimum torrefaction temperatures for sewage sludge.

Microbial enhanced separation of oil from a petroleum refinery sludge.

Science.gov (United States)

Joseph, P J; Joseph, Ammini

2009-01-15

Petroleum refineries around the world have adopted different technological options to manage the solid wastes generated during the refining process and stocking of crude oil. These include physical, chemical and biological treatment methods. In this investigation bacterial mediated oil separation is effected. Two strains of Bacillus were isolated from petroleum-contaminated soils, and inoculated into slurry of sludge, and sludge-sand combinations. The bacteria could effect the separation of oil so as to form a floating scum within 48h with an efficiency of 97% at < or =5% level of sludge in the sludge-sand mixture. The activity was traced to the production of biosurfactants by bacteria.

Paper sludge (PS) to bioethanol: Evaluation of virgin and recycle mill sludge for low enzyme, high-solids fermentation.

Science.gov (United States)

Boshoff, Sonja; Gottumukkala, Lalitha Devi; van Rensburg, Eugéne; Görgens, Johann

2016-03-01

Paper sludge (PS) from the paper and pulp industry consists primarily of cellulose and ash and has significant potential for ethanol production. Thirty-seven PS samples from 11 South African paper and pulp mills exhibited large variation in chemical composition and resulting ethanol production. Simultaneous saccharification and fermentation (SSF) of PS in fed-batch culture was investigated at high solid loadings and low enzyme dosages. Water holding capacity and viscosity of the PS influenced ethanol production at elevated solid loadings of PS. High viscosity of PS from virgin pulp mills restricted the solid loading to 18% (w/w) at an enzyme dosage of 20 FPU/gram dry PS (gdPS), whereas an optimal solid loading of 27% (w/w) was achieved with corrugated recycle mill PS at 11 FPU/gdPS. Ethanol concentration and yield of virgin pulp and corrugated recycle PS were 34.2g/L at 66.9% and 45.5 g/L at 78.2%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multi-step process for concentrating magnetic particles in waste sludges

Science.gov (United States)

Watson, John L.

1990-01-01

This invention involves a multi-step, multi-force process for dewatering sludges which have high concentrations of magnetic particles, such as waste sludges generated during steelmaking. This series of processing steps involves (1) mixing a chemical flocculating agent with the sludge; (2) allowing the particles to aggregate under non-turbulent conditions; (3) subjecting the mixture to a magnetic field which will pull the magnetic aggregates in a selected direction, causing them to form a compacted sludge; (4) preferably, decanting the clarified liquid from the compacted sludge; and (5) using filtration to convert the compacted sludge into a cake having a very high solids content. Steps 2 and 3 should be performed simultaneously. This reduces the treatment time and increases the extent of flocculation and the effectiveness of the process. As partially formed aggregates with active flocculating groups are pulled through the mixture by the magnetic field, they will contact other particles and form larger aggregates. This process can increase the solids concentration of steelmaking sludges in an efficient and economic manner, thereby accomplishing either of two goals: (a) it can convert hazardous wastes into economic resources for recycling as furnace feed material, or (b) it can dramatically reduce the volume of waste material which must be disposed.

Fiscal year 1994 1/25-scale sludge mobilization testing

International Nuclear Information System (INIS)

Powell, M.R.; Gates, C.M.; Hymas, C.R.; Sprecher, M.A.; Morter, N.J.

1995-07-01

There are 28 one-million-gallon double-shell radioactive waste tanks on the Hanford Reservation in southeastern Washington State. The waste in these tanks was generated during processing of nuclear materials. Solids-laden slurries were placed into many of the tanks. Over time, the waste solids have settled to form a layer of sludge in the bottom of these tanks. The sludge layer thickness varies from tank to tank with some having only a few centimeters or no sludge up to some tanks which have about 4.5 m (15 ft) of sludge. It is planned that the waste will be removed from these tanks as part of the overall Hanford site cleanup efforts. Jet mixer pumps are to be placed into the tanks to stir up (mobilize) the sludge and form a uniform slurry suitable for pumping to downstream processing facilities. These mixer pumps use powerful jets of tank fluid directed horizontally out of two, diametrically opposed nozzles near the tank bottom. These fluid jets impinge upon the sludge and stir it up. The amount of sludge mobilized by the mixer pump jets depends not only on the jet properties, but also on the ability of the sludge to resist the jets. It is the goal of the work described in this document to develop the ability to predict how much sludge will be mobilized by the mixer pumps based on the size and velocity of the mixer pump jets and the physical and chemical properties of the tank sludge

Thermogravimetric analysis of the co-combustion of paper mill sludge and municipal solid waste

International Nuclear Information System (INIS)

Hu, Shanchao; Ma, Xiaoqian; Lin, Yousheng; Yu, Zhaosheng; Fang, Shiwen

2015-01-01

Highlights: • Thermogravimetric analysis of paper mill sludge and municipal solid waste were studied. • The combustion of paper mill sludge could be improved by blending municipal solid waste. • There existed significant interaction during co-combustion of the blends. • The OFW and Starink methods were used to obtain the activation energy. • The average activation energy was the lowest by blending 20% municipal solid waste. - Abstract: The thermal characteristics and kinetics of paper mill sludge (PMS), municipal solid waste (MSW) and their blends in the combustion process were investigated in this study. The mass percentages of PMS in the blends were 10%, 30%, 50%, 70% and 90%, respectively. The experiments were carried out at different heating rates (10 °C/min, 20 °C/min and 30 °C/min) and the temperature ranged from room temperature to 1000 °C in a thermogravimetric simultaneous thermal analyzer. The results suggested that the ignition temperature and burnout temperature of MSW were lower than that of PMS, and the mass loss rate of MSW was larger especially at low temperatures. There were only two mass loss peaks in the differential thermogravimetry (DTG) curve, while three mass loss peaks were observed when the blending ratios of PMS were 30%, 50%, 70%. The value of the comprehensive combustion characteristic index of the blends indicated a good combustibility when the percentage of PMS (PPMS) in the blends was less than 30%. There existed certain interaction between the combustion process of PMS and MSW, especially at high temperature stage. Activation energy (E) value obtained by the Ozawa–Flynn–Wall (OFW) method and the Starink method were very consistent. When the mass percentage of PMS in the blends was 80%, the E average value attained the minimum

Optimal policies for activated sludge treatment systems with multi effluent stream generation

Directory of Open Access Journals (Sweden)

Gouveia R.

2000-01-01

Full Text Available Most industrial processes generate liquid waste, which requires treatment prior to disposal. These processes are divided into sectors that generate effluents with time dependent characteristics. Each sector sends the effluent to wastewater treatment plants through pumping-stations. In general, activated sludge is the most suitable treatment and consists of equalization, aeration and settling tanks. During the treatment, there is an increase in the mass of microorganisms, which needs to be removed. Sludge removal represents the major operating costs for wastewater treatment plants. The objective of this work is to propose an optimization model to minimize sludge generation using a superstructure in which the streams from pumping-stations can be sent to the equalization tank. In addition, the aeration tank is divided into cells that can be fed in series and parallel. The model relies on mass balances, kinetic equations, and the resulting Nonlinear Programming problem generates the best operational strategy for the system feed streams with a high substrate removal. Reductions of up to 30 % can be achieved with the proposed strategy maintened BOD efficiency removal upper than 98 %.

Application of Hydrothermal Treatment to High Concentrated Sewage Sludge for Anaerobic Digestion Process

OpenAIRE

M. Orikawa; H. Kamahara; Y. Atsuta; H. Daimon

2013-01-01

Tomato and seaweed were produced by utilizing CO2 and heat discharged from power generation using biogas in Toyogawa biomass park, Japan. The biogas was obtained by anaerobic digestion with hydrothermal treatment. The hydrothermal treatment was applied to the high concentrated sewage sludge (22 % total solids (TS) dewatered sludge). The purpose of this study is to clarify the effect of hydrothermal treatment on the qualities of high concentrated sewage sludge, by analyzing particulate organic...

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.

An integrated approach of composting methodologies for solid waste management

Directory of Open Access Journals (Sweden)

K. Kumaresan

2016-03-01

Full Text Available Organic fraction of solid waste, which upon degradation produces foul smell and generates pathogens, if not properly managed. Composting is not a method of waste disposal but it is a method of waste recycling and used for agricultural purposes. An integrated approach of composting methodology was tested for municipal solid waste management. Solid waste first was composted and after 22 days, was further processed by vermicomposting. Samples were routinely taken for analysis of carbon, nitrogen, moisture content, pH and temperature to determine the quality of composting. Decrease in moisture content to 32.1 %, relative decrease in carbon and nitrogen content were also observed. Among the different types of treatment, municipal solid waste + activated sludge integration showed promising results, followed by vermicomposting municipal solid waste + activated sludge combination, compared to the combinations of dried activated sludge, municipal solid waste + activated sludge semisolid and municipal solid waste + sewage water. Thus, windrow composting followed by vermicomposting gave a better result than other methods. Thus this method would serve as a potential alternative for solid waste management.

An integrated approach of composting methodologies for solid waste management

International Nuclear Information System (INIS)

Kumaresan, K.; Balan, R.; Sridhar, A.; Aravind, J.; Kanmani, P.

2016-01-01

Organic fraction of solid waste, which upon degradation produces foul smell and generates pathogens, if not properly managed. Composting is not a method of waste disposal but it is a method of waste recycling and used for agricultural purposes. An integrated approach of composting methodology was tested for municipal solid waste management. Solid waste first was composted and after 22 days, was further processed by vermicomposting. Samples were routinely taken for analysis of carbon, nitrogen, moisture content, p H and temperature to determine the quality of composting. Decrease in moisture content to 32.1 %, relative decrease in carbon and nitrogen content were also observed. Among the different types of treatment, municipal solid waste + activated sludge integration showed promising results, followed by vermicomposting municipal solid waste + activated sludge combination, compared to the combinations of dried activated sludge, municipal solid waste + activated sludge semisolid and municipal solid waste + sewage water. Thus, windrow composting followed by vermicomposting gave a better result than other methods. Thus this method would serve as a potential alternative for solid waste management.

CHEMICAL DIFFERENCES BETWEEN SLUDGE SOLIDS AT THE F AND H AREA TANK FARMS

Energy Technology Data Exchange (ETDEWEB)

Reboul, S.

2012-08-29

and HTF samples indicated that the primary crystalline compounds of iron in sludge solids are Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, and FeO(OH), and the primary crystalline compounds of aluminum are Al(OH){sub 3} and AlO(OH). Also identified were carbonate compounds of calcium, magnesium, and sodium; a nitrated sodium aluminosilicate; and various uranium compounds. Consistent with expectations, oxalate compounds were identified in solids associated with oxalic acid cleaning operations. The most likely oxidation states and chemical forms of technetium are assessed in the context of solubility, since technetium-99 is a key risk driver from an environmental fate and transport perspective. The primary oxidation state of technetium in SRS sludge solids is expected to be Tc(IV). In salt waste, the primary oxidation state is expected to be Tc(VII). The primary form of technetium in sludge is expected to be a hydrated technetium dioxide, TcO{sub 2} {center_dot} xH{sub 2}O, which is relatively insoluble and likely co-precipitated with iron. In salt waste solutions, the primary form of technetium is expected to be the very soluble pertechnetate anion, TcO{sub 4}{sup -}. The relative differences between the F and H Tank Farm waste provide a basis for anticipating differences that will occur as constituents of FTF and HTF waste residue enter the environment over the long-term future. If a constituent is significantly more dominant in one of the Tank Farms, its long-term environmental contribution will likely be commensurately higher, assuming the environmental transport conditions of the two Tank Farms share some commonality. It is in this vein that the information cited in this document is provided - for use during the generation, assessment, and validation of Performance Assessment modeling results.

Sewage sludge solubilization by high-pressure homogenization.

Science.gov (United States)

Zhang, Yuxuan; Zhang, Panyue; Guo, Jianbin; Ma, Weifang; Fang, Wei; Ma, Boqiang; Xu, Xiangzhe

2013-01-01

The behavior of sludge solubilization using high-pressure homogenization (HPH) treatment was examined by investigating the sludge solid reduction and organics solubilization. The sludge volatile suspended solids (VSS) decreased from 10.58 to 6.67 g/L for the sludge sample with a total solids content (TS) of 1.49% after HPH treatment at a homogenization pressure of 80 MPa with four homogenization cycles; total suspended solids (TSS) correspondingly decreased from 14.26 to 9.91 g/L. About 86.15% of the TSS reduction was attributed to the VSS reduction. The increase of homogenization pressure from 20 to 80 MPa or homogenization cycle number from 1 to 4 was favorable to the sludge organics solubilization, and the protein and polysaccharide solubilization linearly increased with the soluble chemical oxygen demand (SCOD) solubilization. More proteins were solubilized than polysaccharides. The linear relationship between SCOD solubilization and VSS reduction had no significant change under different homogenization pressures, homogenization cycles and sludge solid contents. The SCOD of 1.65 g/L was solubilized for the VSS reduction of 1.00 g/L for the three experimental sludge samples with a TS of 1.00, 1.49 and 2.48% under all HPH operating conditions. The energy efficiency results showed that the HPH treatment at a homogenization pressure of 30 MPa with a single homogenization cycle for the sludge sample with a TS of 2.48% was the most energy efficient.

Batch Fermentative Biohydrogen Production Process Using Immobilized Anaerobic Sludge from Organic Solid Waste

Directory of Open Access Journals (Sweden)

Patrick T. Sekoai

2016-12-01

Full Text Available This study examined the potential of organic solid waste for biohydrogen production using immobilized anaerobic sludge. Biohydrogen was produced under batch mode at process conditions of 7.9, 30.3 °C and 90 h for pH, temperature and fermentation time, respectively. A maximum biohydrogen fraction of 48.67%, which corresponded to a biohydrogen yield of 215.39 mL H2/g Total Volatile Solids (TVS, was achieved. Therefore, the utilization of immobilized cells could pave the way for a large-scale biohydrogen production process.

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.

Analysis of Organic and Inorganic Contaminants in Dried Sewage Sludge and By-Products of Dried Sewage Sludge Gasification

Directory of Open Access Journals (Sweden)

Sebastian Werle

2014-01-01

Full Text Available Organic and inorganic contaminants in sewage sludge may cause their presence also in the by-products formed during gasification processes. Thus, this paper presents multidirectional chemical instrumental activation analyses of dried sewage sludge as well as both solid (ash, char coal and liquid (tar by-products formed during sewage gasification in a fixed bed reactor which was carried out to assess the extent of that phenomenon. Significant differences were observed in the type of contaminants present in the solid and liquid by-products from the dried sewage sludge gasification. Except for heavy metals, the characteristics of the contaminants in the by-products, irrespective of their form (solid and liquid, were different from those initially determined in the sewage sludge. It has been found that gasification promotes the migration of certain valuable inorganic compounds from sewage sludge into solid by-products which might be recovered. On the other hand, the liquid by-products resulting from sewage sludge gasification require a separate process for their treatment or disposal due to their considerable loading with toxic and hazardous organic compounds (phenols and their derivatives.

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.)

Enhanced high-solids anaerobic digestion of waste activated sludge by the addition of scrap iron.

Science.gov (United States)

Zhang, Yaobin; Feng, Yinghong; Yu, Qilin; Xu, Zibin; Quan, Xie

2014-05-01

Anaerobic digestion of waste activated sludge usually requires pretreatment procedure to improve the bioavailability of sludge, which involves considerable energy and high expenditures. This study proposes a cost-effective method for enhanced anaerobic digestion of sludge without a pretreatment by directly adding iron into the digester. The results showed that addition of Fe(0) powder could enhance 14.46% methane yield, and Fe scrap (clean scrap) could further enhance methane yield (improving rate 21.28%) because the scrap has better mass transfer efficiency with sludge and liquid than Fe(0) powder. The scrap of Fe with rust (rusty scrap) could induce microbial Fe(III) reduction, which resulted in achieving the highest methane yield (improving rate 29.51%), and the reduction rate of volatile suspended solids (VSS) was also highest (48.27%) among Fe powder, clean scrap and rusty scrap. PCR-DGGE proved that the addition of rusty scrap could enhance diversity of acetobacteria and enrich iron-reducing bacteria to enhance degradation of complex substrates. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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

Assessment of sludges and tank bottoms treatment processes

International Nuclear Information System (INIS)

Bhutto, A.W.; Bazmi, A.A.

2005-01-01

The petroleum refining industries generate considerable amounts of sludge and tank bottoms as waste. Petroleum refinery receives crude oil containing emulsified water and solids. As the crude oil storage tanks are repeatedly filled and emptied, the water and solids settle towards the bottom as sludge. For tanks that have been in service for several years, the sludge accumulation becomes several feet deep, results in a loss of ullage in refinery crude storage tanks. The accumulation of crude storage tank bottoms is a serious problem experienced by local refineries. The refinery sludge waste is categorized as hazardous waste, which is at present buried in the tankform ground. Since the no hazardous material land filling option available, the disposal of these hazardous materials has become a major problem because of the ISO-14000 certification requirements and expectation of stakeholder. To maximize the waste oil recovery from sludge and tank bottoms and to minimize the volume of the hazardous waste, a number of waste recovery and treatment processes are available. The process designs and unit operations of each process are different and each has its own merits, in terms of the technical complexity, operation friendliness, and costs and economics. A study on each of these technologies and the subsequent tide-up to the existing unit operations is conducted, and the associated technical comparisons are made. (author)

Improve biogas production from low-organic-content sludge through high-solids anaerobic co-digestion with food waste.

Science.gov (United States)

Liu, Chuanyang; Li, Huan; Zhang, Yuyao; Liu, Can

2016-11-01

Anaerobic co-digestion of sewage sludge and food waste was tested at two different total solid (TS) concentrations. In the low-solids group with TS 4.8%, the biogas production increased linearly as the ratio of food waste in substrate increased from 0 to 100%, but no synergetic effect was found between the two substrates. Moreover, the additive food waste resulted in the accumulation of volatile fatty acids and decelerated biogas production. Thus, the blend ratio of food waste should be lower than 50%. While in the high-solids group with TS 14%, the weak alkaline environment with pH 7.5-8.5 avoided excessive acidification but high concentration of free ammonia was a potential risk. However, good synergetic effect was found between the two substrates because the added food waste improved mass transfer in sludge cake. Thus, 50% was recommended as the optimum ratio of food waste in substrate because of the best synergetic effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

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

Distributed and micro-generation from biogas and agricultural application of sewage sludge: Comparative environmental performance analysis using life cycle approaches

International Nuclear Information System (INIS)

Sadhukhan, Jhuma

2014-01-01

Highlights: • 180,000 MJ biogas from 15.87 t sewage sludge supply 1 household electricity per year. • From the highest to the lowest avoided impacts: PEM FC 2 eq./MJ compared to natural gas. • 1 m 3 biogas production from ∼3.2 t sewage sludge AD can save 0.92 m 3 natural gas. • Digested matter causes eutrophication and toxicity potentials. - Abstract: The Feed-In-Tariff scheme in the UK has generated attractive economics in the investment for anaerobic digestion (AD) to convert sewage sludge into biogas and digested sludge for energy and agricultural applications, respectively. The biogas is a source of biomethane to replace natural gas in the gas grid system. Biogas can be utilised to generate combined heat and power (CHP) on-site, at household micro and distributed or community scales. These biogas CHP generation options can replace the equivalent natural gas based CHP generation options. Digested sludge can be transformed into fertiliser for agricultural application replacing inorganic N:P:K fertiliser. Biogas and digested matter yields are inter-dependent: when one increases, the other decreases. Hence, these various options need to be assessed for avoided life cycle impact potentials, to understand where greatest savings lie and in order to rank these options for informed decision making by water industries. To fill a gap in the information available to industry dealing with wastewater, the avoided emissions by various AD based technologies, in primary impact potentials that make a difference between various systems, have been provided in this paper. 1 m 3 biogas can save 0.92 m 3 natural gas. An average UK household (with a demand of 2 kWe) requires 180,000 MJ or 5000 Nm 3 or 4.76 t biogas per year, from 15.87 t sewage sludge processed through AD. The proton exchange membrane fuel cell (PEM FC) is suitable for building micro-generations; micro gas turbine (Micro GT), solid oxide fuel cell (SOFC) and SOFC-GT hybrid are suitable for distributed

Concentration processes under tubesheet sludge piles in nuclear steam generators

International Nuclear Information System (INIS)

Gonzalez, F.; Spekkens, P.

1987-01-01

The process by which bulk water solutes are concentrated under tubesheet sludge piles in nuclear steam generators was investigated in the laboratory under simulated CANDU operating conditions. Concentration rates were found to depend on the tube heat flux and pile depth, although beyond a critical depth the concentration efficiency decreased. This efficiency could be expressed by a concentration coefficient, and was found to depend also on the sludge pile porosity. Solute concentration profiles in the sludge pile suggested that the concentration mechanism in a high-porosity/permeability pile is characterized by boiling mainly near or at the tube surface, while in low-porosity piles, the change of phase may also become important in the body of the sludge pile. In all cases, the full depth of the pile was active to some extent in the concentration process. As long as the heat transfer under the pile was continued, the solute remained under the pile and slowly migrated toward the bottom. When the heat transfer was stopped, the solute diffused back into the bulk solution at a rate slower than that of the concentration process

Engineering evaluation of solids/liquids separation processes applicable to sludge treatment project

International Nuclear Information System (INIS)

Duncan, J.B.

1998-01-01

This engineering study looks at the solids/liquids separation unit operations after the acid dissolution of the K Basin sludge treatment. Unit operations considered were centrifugation, filtration (cartridge, cross flow, and high shear filtration) and gravity settling. The recommended unit operations for the solids/liquids separations are based upon the efficiency, complexity, and off-the-shelf availability and adaptability. The unit operations recommended were a Robatel DPC 900 centrifuge followed by a nuclearized 31WM cartridge filter. The Robatel DPC 900 has been successfully employed in the nuclear industry on a world wide scale. The 31WM cartridge filter has been employed for filtration campaigns in both the government and civilian nuclear arenas

Exploiting the energy potential of waste activated sludge with MicroSludge[Manure, biosolids, and organic industrial/commercial residuals in land applications programs : improving beneficial reuse and protection of water quality

Energy Technology Data Exchange (ETDEWEB)

Stephenson, R.; Laliberte, S. [Paradigm Environmental Technologies, Vancouver, BC (Canada); Nemeth, L. [Earth Tech Canada Inc., Burnaby, BC (Canada)

2007-07-01

When waste activated sludge (WAS) is efficiently converted to biogas through anaerobic digestion, the energy potential and economic value of WAS can be exploited. This paper discussed the chemical and pressure pre-treatment process using MicroSludge. MicroSludge uses alkaline pre-treatment to weaken cell membranes and a high-pressure homogenizer to liquefy the cells, enabling the anaerobic digester to work at a higher rate and more efficiently, destroying pathogens and generating less biosolids for disposal, with corresponding higher volumes of methane from which to generate added electrical power and/or produce added heat. MicroSludge was demonstrated at the Chilliwack waste water treatment plant (WWTP), located 115 km east of Vancouver. The paper provided a description of the Chilliwack WWTP and discussed the application of MicroSludge at a full-scale prototype plant. The MicroSludge plant was capable of pre-treating all of the waste secondary sludge generated at the Chilliwack WWTP prior to anaerobic digestion. The paper also discussed digester hydraulic retention time; scanning electron microscope images; temperature; pH; mass loading of primary sludge and waste activated sludge; total volatile solids concentrations; and digester gas composition. Operating and maintenance costs were also outlined along with electrical power costs, maintenance costs and chemical costs. Last, the paper presented the energy benefits for WWTPs when using MicroSludge. It was concluded that the economic benefits of MicroSludge are greater for plants with higher biosolids disposal costs and higher electrical utility costs. 6 refs., 8 tabs., 10 figs.

Characterization of tannery sludge from the leather industry of Franca industrial district, SP, Brazil

International Nuclear Information System (INIS)

Chambi, M.M.; Toffoli, S.M.

2011-01-01

The industry of leather manufacture generates large quantities of solid leather waste with characteristics of high-polluting and hazardous conditions. Among these wastes, stands out the wet blue leather (chromed leather scraps), and the tanning sludge and secondary sludge generated in the processes of effluents treatment. These wastes contain Cr(III), which, under oxidizing conditions, can turn into Cr (VI), which is highly toxic. However, these wastes are a potential source of chromium oxide (traditional industrial pigment), which could be used by the glass and ceramic enamel industries. In this study, a preliminary characterization of a chromium sludge from the industrial district of Franca-SP was conducted. X-ray diffraction (XRD), chemical (XRF) and thermal (DTA / TG) analyses were used to determine the physical and chemical characteristics of this solid waste. The potential of using this material as an available and cheap pigment for the manufacture of enamels and glass is discussed. (author)

Technology for improving sludge concentration; Odei noshukusei kaizen gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-10

Sludge generating in a sewage treatment plant is disposed through the processes such as concentration, dehydration, and incineration in sludge disposal facilities. In recent years, there has been a trend that this sludge increases in volume as well as worsens in the concentration. A case is predictable where the sludge load to the dehydrating process is so large that the sludge can no longer be processed in sufficient quantity. In the meantime, if sludge is ozone-treated, viscous substance on the surface of sludge particles can be separated with a comparatively small amount of ozone, with sludge concentration enhanced. At Meidensha, an experimental plant was set up for the ozone treatment of sludge in a sludge intensive treatment plant of a metropolis, with a verification experiment carried out for a sludge concentration improving system by ozone. As a result of comparison of the treatment performance between an assessment system for performing ozone treatment and a reference system for not performing, the average value of the sludge concentration of a gravity concentration tank was 1.9% of the reference system against 1.7% of the assessment system in a continuous treatment experiment in the summer, while the solid collection ratio was 65.8% of the reference system against 95.5% of the assessment system, enabling a superior improving effect to be obtained. (NEDO)

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.

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.

Filterability and Sludge Concentration in Membrane Bioreactors

NARCIS (Netherlands)

Lousada-Ferreira, M.

2011-01-01

The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of

Bench-Scale Evaluation of the Genifuel Hydrothermal Processing Technology for Wastewater Solids

Energy Technology Data Exchange (ETDEWEB)

Marrone, Philip A.; Elliott, Douglas C.; Billing, Justin M.; Hallen, Richard T.; Hart, Todd R.; Kadota, Paul; Moeller, Jeff C.; Randel, Margaaret A.; Schmidt, Andrew J.

2017-10-03

Hydrothermal Liquefaction (HTL) and Catalytic Hydrothermal Gasification (CHG) proof-of-concept bench-scale tests were performed to assess the potential of the Genifuel hydrothermal process technology for handling municipal wastewater sludge. HTL tests were conducted at 300-350°C and 20 MPa on three different feeds: primary sludge (11.9 wt% solids), secondary sludge (9.7 wt% solids), and post-digester sludge (also referred to as digested solids) (16.0 wt% solids). Corresponding CHG tests were conducted at 350°C and 20 MPa on the HTL aqueous phase output using a ruthenium based catalyst. A comprehensive analysis of all feed and effluent phases was also performed. Total mass and carbon balances closed to within ± 15% in all but one case. Biocrude yields from HTL tests were 37%, 25%, and 34% for primary sludge, secondary sludge, and digested solids feeds, respectively. The biocrude yields accounted for 59%, 39%, and 49% of the carbon in the feed for primary sludge, secondary sludge, and digested solids feeds, respectively. Biocrude composition and quality were comparable to that seen with biocrudes generated from algae feeds. Subsequent hydrotreating (i.e., upgrading) of the biocrude produced from primary sludge and digested solids resulted in a product with comparable physical and chemical properties to petroleum crude oil. CHG product gas consisted primarily of methane, with methane yields (relative to CHG input) on a carbon basis of 47%, 61%, and 64% for aqueous feeds that were the output of HTL tests with primary sludge, secondary sludge, and digested solids, respectively. Siloxane concentrations in the CHG product gas were below the detection limit and well below fuel input composition limits set by several engine manufacturers. Relative to that of the sludge feeds, the HTL-CHG process resulted in a reduction in chemical oxygen demand (COD) of greater than 99.9% and a reduction in residual solids for disposal of 94-99%. The test results, as a whole, support

The influences of inoculants from municipal sludge and solid waste on compost stability, maturity and enzyme activities during chicken manure composting.

Science.gov (United States)

Li, Shuyan; Li, Jijin; Yuan, Jing; Li, Guoxue; Zang, Bing; Li, Yangyang

2017-07-01

The aim of this study was to investigate the influence of inoculants on compost stability, maturity and enzyme activities during composting of chicken manure and cornstalk. Two microbial inoculants (originated from aerobic municipal sludge and municipal solid waste, respectively) were used in composting at the rate of 0.3% of initial raw materials (wet weight). No microbial inoculums were added to the control. The experiment was conducted under aerobic conditions for 53 days. The results show that enzyme activity is an important index to comprehensively evaluate the composting stability and maturity. Microbes originated from sludge works best in terms of composting stability and maturity (C:N ratio decreased from 15.5 to 10, and germination index increased to 109%). Microbial inoculums originated from sludge and municipal solid waste extended the time of thermophilic phase for 11 and 7 days, respectively. Microbial inoculums originated from sludge and MSW significantly increased the average of catalase activity (by 15.0% and 12.1%, respectively), urease activity (by 21.5% and 12.2%, respectively) and cellulase activity (by 32.1% and 26.1%, respectively) during composting.

Waste activated sludge fermentation: effect of solids retention time and biomass concentration.

Science.gov (United States)

Yuan, Q; Sparling, R; Oleszkiewicz, J A

2009-12-01

Laboratory scale, room temperature, semi-continuous reactors were set-up to investigate the effect of solids retention time (SRT, equal to HRT hydraulic retention time) and biomass concentration on generation of volatile fatty acids (VFA) from the non-methanogenic fermentation of waste activated sludge (WAS) originating from an enhanced biological phosphorus removal process. It was found that VFA yields increased with SRT. At the longest SRT (10d), improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield from the influent COD (0.14g VFA-COD/g TCOD). It was also observed that under the same SRT, VFA yields increased when the biomass concentration decreased. At a 10d SRT the VFA yield increased by 46%, when the biomass concentration decreased from 13g/L to 4.8g/L. Relatively high nutrient release was observed during fermentation. The average phosphorus release was 17.3mg PO(4)-P/g TCOD and nitrogen release was 25.8mg NH(4)-N/g TCOD.

Effect of sewage sludge content on gas quality and solid residues produced by cogasification in an updraft gasifier

Energy Technology Data Exchange (ETDEWEB)

Seggiani, Maurizia, E-mail: m.seggiani@diccism.unipi.it [Department of Chemical Engineering, Industrial Chemistry and Material Science, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa (Italy); Puccini, Monica, E-mail: m.puccini@diccism.unipi.it [Department of Chemical Engineering, Industrial Chemistry and Material Science, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa (Italy); Raggio, Giovanni, E-mail: g.raggio@tiscali.it [Italprogetti Engineering SPA, Lungarno Pacinotti, 59/A, 56020 San Romano (Pisa) (Italy); Vitolo, Sandra, E-mail: s.vitolo@diccism.unipi.it [Department of Chemical Engineering, Industrial Chemistry and Material Science, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa (Italy)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Cogasification of sewage sludge with wood pellets in updraft gasifier was analysed. Black-Right-Pointing-Pointer The effects of sewage sludge content on the gasification process were examined. Black-Right-Pointing-Pointer Sewage sludge addition up to 30 wt.% reduces moderately the process performance. Black-Right-Pointing-Pointer At high sewage sludge content slagging and clinker formation occurred. Black-Right-Pointing-Pointer Solid residues produced resulted acceptable at landfills for non-hazardous waste. - Abstract: In the present work, the gasification with air of dehydrated sewage sludge (SS) with 20 wt.% moisture mixed with conventional woody biomass was investigated using a pilot fixed-bed updraft gasifier. Attention was focused on the effect of the SS content on the gasification performance and on the environmental impact of the process. The results showed that it is possible to co-gasify SS with wood pellets (WPs) in updraft fixed-bed gasification installations. However, at high content of sewage sludge the gasification process can become instable because of the very high ash content and low ash fusion temperatures of SS. At an equivalent ratio of 0.25, compared with wood pellets gasification, the addition of sewage sludge led to a reduction of gas yield in favor of an increase of condensate production with consequent cold gas efficiency decrease. Low concentrations of dioxins/furans and PAHs were measured in the gas produced by SS gasification, well below the limiting values for the exhaust gaseous emissions. NH{sub 3}, HCl and HF contents were very low because most of these compounds were retained in the wet scrubber systems. On the other hand, high H{sub 2}S levels were measured due to high sulfur content of SS. Heavy metals supplied with the feedstocks were mostly retained in gasification solid residues. The leachability tests performed according to European regulations showed that metals leachability was

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.

Mitigation of Hydrogen Gas Generation from the Reaction of Water with Uranium Metal in K Basins Sludge

International Nuclear Information System (INIS)

Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

2010-01-01

Means to decrease the rate of hydrogen gas generation from the chemical reaction of uranium metal with water were identified by surveying the technical literature. The underlying chemistry and potential side reactions were explored by conducting 61 principal experiments. Several methods achieved significant hydrogen gas generation rate mitigation. Gas-generating side reactions from interactions of organics or sludge constituents with mitigating agents were observed. Further testing is recommended to develop deeper knowledge of the underlying chemistry and to advance the technology aturation level. Uranium metal reacts with water in K Basin sludge to form uranium hydride (UH3), uranium dioxide or uraninite (UO2), and diatomic hydrogen (H2). Mechanistic studies show that hydrogen radicals (H·) and UH3 serve as intermediates in the reaction of uranium metal with water to produce H2 and UO2. Because H2 is flammable, its release into the gas phase above K Basin sludge during sludge storage, processing, immobilization, shipment, and disposal is a concern to the safety of those operations. Findings from the technical literature and from experimental investigations with simple chemical systems (including uranium metal in water), in the presence of individual sludge simulant components, with complete sludge simulants, and with actual K Basin sludge are presented in this report. Based on the literature review and intermediate lab test results, sodium nitrate, sodium nitrite, Nochar Acid Bond N960, disodium hydrogen phosphate, and hexavalent uranium [U(VI)] were tested for their effects in decreasing the rate of hydrogen generation from the reaction of uranium metal with water. Nitrate and nitrite each were effective, decreasing hydrogen generation rates in actual sludge by factors of about 100 to 1000 when used at 0.5 molar (M) concentrations. Higher attenuation factors were achieved in tests with aqueous solutions alone. Nochar N960, a water sorbent, decreased hydrogen

Mitigation of Hydrogen Gas Generation from the Reaction of Water with Uranium Metal in K Basins Sludge

Energy Technology Data Exchange (ETDEWEB)

Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

2010-01-29

Means to decrease the rate of hydrogen gas generation from the chemical reaction of uranium metal with water were identified by surveying the technical literature. The underlying chemistry and potential side reactions were explored by conducting 61 principal experiments. Several methods achieved significant hydrogen gas generation rate mitigation. Gas-generating side reactions from interactions of organics or sludge constituents with mitigating agents were observed. Further testing is recommended to develop deeper knowledge of the underlying chemistry and to advance the technology aturation level. Uranium metal reacts with water in K Basin sludge to form uranium hydride (UH3), uranium dioxide or uraninite (UO2), and diatomic hydrogen (H2). Mechanistic studies show that hydrogen radicals (H·) and UH3 serve as intermediates in the reaction of uranium metal with water to produce H2 and UO2. Because H2 is flammable, its release into the gas phase above K Basin sludge during sludge storage, processing, immobilization, shipment, and disposal is a concern to the safety of those operations. Findings from the technical literature and from experimental investigations with simple chemical systems (including uranium metal in water), in the presence of individual sludge simulant components, with complete sludge simulants, and with actual K Basin sludge are presented in this report. Based on the literature review and intermediate lab test results, sodium nitrate, sodium nitrite, Nochar Acid Bond N960, disodium hydrogen phosphate, and hexavalent uranium [U(VI)] were tested for their effects in decreasing the rate of hydrogen generation from the reaction of uranium metal with water. Nitrate and nitrite each were effective, decreasing hydrogen generation rates in actual sludge by factors of about 100 to 1000 when used at 0.5 molar (M) concentrations. Higher attenuation factors were achieved in tests with aqueous solutions alone. Nochar N960, a water sorbent, decreased hydrogen

Characteristics of residues from thermally treated anaerobic sludges

International Nuclear Information System (INIS)

Friedman, A.A.; Smith, J.E.; De Santis, J.; Ptak, T.; Ganley, R.C.

1988-01-01

Sludge management and disposal are probably the most difficult and expensive operations involved in wastewater treatment today. To minimize final disposal costs many waste treatment facilities practice some form of anaerobic digestion and dewatering to reduce the volume and offensiveness of their by-product sludges. One potential alternative for reducing sludge volumes consists of high temperature, partial oxidation of these previously digested sludges (PDS) and subsequent anaerobic biological conversion of resulting soluble organics to methane. This paper describes solids destruction, residue characteristics and biodegradability factors that should be considered in the design of liquid thermal treatment processes for the management of anaerobic sludges. To date only very limited information is available concerning the suitability of thermally treated PDS to serve as a substrate for the generation of methane. The primary objective of this research was to determine the feasibility of producing methane efficiently from the residual VSS in anaerobically digested sludges. Secondary goals were to establish the ''best'' conditions for thermal treatment for solubilizing PDS, to observe the effect of the soluble products on methanogenesis and to evaluate process sidestreams for dewaterability and anaerobic biodegradability

The effect of bioleaching on sewage sludge pyrolysis.

Science.gov (United States)

Chen, Zhihua; Hu, Mian; Cui, Baihui; Liu, Shiming; Guo, Dabin; Xiao, Bo

2016-02-01

The effects of bioleaching on sewage sludge pyrolysis were studied. Sewage sludge was treated by bioleaching with solid concentrations of 6% (w/v), 8% (w/v), 10% (w/v). Results showed that bioleaching treatment could modify the physicochemical properties of sewage sludge and enhance the metals removal. The optimum removal efficiencies of heavy metals were achieved with solid concentration of 6% (w/v) bioleaching treatment: Cu, 73.08%; Zn, 78.67%; Pb, 24.65%; Cd, 79.46%. The characterization results of thermogravimetric analysis (TGA) showed that the bioleached sewage sludge with a 6% (w/v) solid concentration treatment was the easiest to decompose. Pyrolytic experiments of bioleached sewage sludge were performed in a laboratory-scale fixed bed reactor. Results indicated that bioleaching treatment greatly influenced the product yields and gas composition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chemical cleaning for sludge in steam generator of nuclear power plant

International Nuclear Information System (INIS)

Zhang Mengqin; Lu Yucheng; Zhang Binyong; Yu Jinghua

2002-01-01

The sludge induced corrosion damage to secondary side of tubes of Steam Generator (SG), effect of chemical cleaning technique on maintenance integrity of tubes of SG NPP and use of chemical cleaning technique in SG NPP have been summarized. The engineering technique of chemical cleaning for removing sludge in secondary side of SG NPP has been studied and qualified by CIAE (China Institute of Atomic Energy). Chemical cleaning engineering technique is introduced (main agent is EDTA, temp. <100 degree C), including chemical cleaning technology for tube plate and full tube nest of secondary side of SG, the monitoring technique of chemical cleaning process (effectiveness and safety), the disposal method of wastage of chemical cleaning, the system of chemical cleaning. The method for preventing sludge deposition in secondary side and the research on advanced water chemistry of secondary loop are introduced

Device for removing and recuperating sludge deposited on the tube plate of a steam generator

International Nuclear Information System (INIS)

Bes, Louis.

1982-01-01

The cleaning device includes a descaling ramp with high pressure jets permanently fixed inside the steam generator, a system for driving the sludge formed towards the centre of the tube plate and a valve for removing the sludge giving into a hollow central column [fr

Is the biochar produced from sewage sludge a good quality solid fuel?

Directory of Open Access Journals (Sweden)

Pulka Jakub

2016-12-01

Full Text Available The influence of sewage sludge torrefaction temperature on fuel properties was investigated. Non-lignocellulosic waste thermal treatment experiment was conducted within 1 h residence time, under the following temperatures: 200, 220, 240, 260, 280 and 300°C. Sawdust was used as lignocellulosic reference material. The following parameters of biochar have been measured: moisture, higher heating value, ash content, volatile compounds and sulfur content. Sawdust biochar has been confirmed to be a good quality solid fuel. High ash and sulfur content may be an obstacle for biochar energy reuse. The best temperature profile for sawdust torrefaction and fuel production for 1 h residence time was 220°C. At this temperature the product contained 84% of initial energy while decreased the mass by 25%. The best temperature profile for sewage sludge was 240°C. The energy residue was 91% and the mass residue was 85%. Higher temperatures in both cases caused excessive mass and energy losses.

Optimization of inoculum to substrate ratio for bio-energy generation in co-digestion of tannery solid wastes

Energy Technology Data Exchange (ETDEWEB)

Sri Bala Kameswari, K.; Chitra Kalyanaraman,; Porselvam, S. [Central Leather Research Institute (CLRI), Environmental Technology Division, Chennai (India); Thanasekaran, K. [Anna University, Centre for Environmental Studies, Chennai (India)

2012-04-15

The inoculum to substrate (I/S) ratio is an important factor which influences the anaerobic digestion process. In this study, the effect of different I/S ratios on the performance of co-digestion of fleshings along with mixture of sludge generated during treatment of tannery wastewater was investigated. The parameters studied were biogas generation, volatile solids reduction, volatile fatty acid (VFA) production, and the stability of the digestion process based on VFA to alkalinity ratio was evaluated for various I/S ratios. Economical significance of I/S ratio as related to the volume of the anaerobic digester and the potential benefit of bio-energy generated are discussed in detail. (orig.)

Continuous biohydrogen production from waste bread by anaerobic sludge.

Science.gov (United States)

Han, Wei; Huang, Jingang; Zhao, Hongting; Li, Yongfeng

2016-07-01

In this study, continuous biohydrogen production from waste bread by anaerobic sludge was performed. The waste bread was first hydrolyzed by the crude enzymes which were generated by Aspergillus awamori and Aspergillus oryzae via solid-state fermentation. It was observed that 49.78g/L glucose and 284.12mg/L free amino nitrogen could be produced with waste bread mass ratio of 15% (w/v). The waste bread hydrolysate was then used for biohydrogen production by anaerobic sludge in a continuous stirred tank reactor (CSTR). The optimal hydrogen production rate of 7.4L/(Ld) was achieved at chemical oxygen demand (COD) of 6000mg/L. According to the results obtained from this study, 1g waste bread could generate 0.332g glucose which could be further utilized to produce 109.5mL hydrogen. This is the first study which reports continuous biohydrogen production from waste bread by anaerobic sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gravitational sedimentation of flocculated waste activated sludge.

Science.gov (United States)

Chu, C P; Lee, D J; Tay, J H

2003-01-01

The sedimentation characteristics of flocculated wastewater sludge have not been satisfactorily explored using the non-destructive techniques, partially owing to the rather low solid content (ca. 1-2%) commonly noted in the biological sediments. This paper investigated, for the first time, the spatial-temporal gravitational settling characteristics of original and polyelectrolyte flocculated waste activated sludge using Computerized Axial Tomography Scanner. The waste activated sludge possessed a distinct settling characteristic from the kaolin slurries. The waste activated sludges settled more slowly and reached a lower solid fraction in the final sediment than the latter. Flocculation markedly enhanced the settleability of both sludges. Although the maximum achievable solid contents for the kaolin slurries were reduced, flocculation had little effects on the activated sludge. The purely plastic rheological model by Buscall and White (J Chem Soc Faraday Trans 1(83) (1987) 873) interpreted the consolidating sediment data, while the purely elastic model by Tiller and Leu (J. Chin. Inst. Chem. Eng. 11 (1980) 61) described the final equilibrated sediment. Flocculation produced lower yield stress during transient settling, thereby resulting in the more easily consolidated sludge than the original sample. Meanwhile, the flocculated activated sludge was stiffer in the final sediment than in the original sample. The data reported herein are valuable to the theories development for clarifier design and operation.

Heavy Metals and Radioactivity Reduction from Acid Mine Drainage Lime Neutralized Sludge

Science.gov (United States)

Mashifana, T.; Sithole, N.

2018-03-01

The worldwide known treatment processes of acid mine drainage result into the formation of hydrous ferric oxides that is amorphous, poorly crystalline and into the generation of hazardous voluminous sludge posing threat to the environment. Applicable treatment technologies to treat hazardous solid material and produce useful products are limited and in most cases nonexistence. A chemical treatment process utilizing different reagents was developed to treat hazardous acid mine drainage (AMD) sludge with the objectives to conduct radioactivity assessment of the sludge generated from lime treatment process and determine the reagent that provides the best results. Leaching with 0.5 M citric acid, 0.4 M oxalic acid, 0.5 M sodium carbonate and 0.5 M sodium bicarbonate was investigated. The leaching time applied was 24 hours at 25 °C. The characterization of the raw AMD revealed that the AMD sludge from lime treatment process is radioactive. The sludge was laden with radioactive elements namely, 238U, 214Pb, 226Ra, 232Th, 40K and 214Bi. 0.5 M citric acid provided the best results and the hazardous contaminants were significantly reduced. The constituents in the sludge after treatment revealed that there is a great potential for the sludge to be used for other applications such as building and construction.

Biomass stabilization in the anaerobic digestion of wastewater sludges

Energy Technology Data Exchange (ETDEWEB)

Arnaiz, C. [Universidad de Sevilla, Dept. de Ingenieria Quimica y Ambiental, Sevilla (Spain); Gutierrez, J.C. [Universidad Pablo de Olavide, Dept. de Ciencias Ambientales, Sevilla (Spain); Lebrato, J. [Universidad de Sevilla, Grupo Tratamiento de Aguas Residuales, Sevilla (Spain)

2005-07-01

Sludge stabilization processes include both volatile solid destruction and biomass stabilization. Traditionally, both processes have been considered together, in such a way that, when volatile solid destruction is achieved, the biomass is considered stabilized. In this study, volatile solids reduction and biomass stabilization in the anaerobic digestion of primary, secondary and mixed sludges from municipal wastewater treatment plants were researched in batch cultures by measurements of suspended solids and suspended lipid-phosphate. The estimated kinetic constants were higher in all sludge types tested for the biomass stabilization process, indicating that volatile solids destruction and biomass stabilization are not parallel processes, since the latter one is reached before the former. (Author)

Characterization of Tank 51 Sludge Slurry Samples (HTF-51-17-67, -68, -69, -74, -75, and -76) in Support of Sludge Batch 10 Processing

Energy Technology Data Exchange (ETDEWEB)

Oji, L. N. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Reboul, S. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-11-09

The Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) Engineering (SRR-E) to provide sample characterization and analyses of Tank 51 sludge samples in support of Sludge Batch (SB) 10. The six Tank 51 sludge samples were sampled and delivered to SRNL in August of 2017. These six Tank 51 sludge samples, after undergoing physical characterizations which included rheology, weight percent total solid, dissolved solids and density measurements, were combined into one composite Tank 51 sample and analyzed for corrosion controls analytes, select radionuclides, chemical elements, density and weight percent total solids.

Separation of SRP waste sludge and supernate

International Nuclear Information System (INIS)

Stone, J.A.

1976-01-01

Sludges and supernates were separated from Savannah River Plant waste slurries by centrifugation and sand filtration. This separation, a portion of a conceptual process for solidification and long-term storage of high-level radioactive wastes, was tested in shielded cells with small-scale process equipment. Procedures for the separation were developed in tests with nonradioactive materials. Then, in 13 tests with actual sludges and supernates, solids removal ranged from 90 to 99.2 vol percent and averaged 96.4 vol percent after two passes through a basket-type centrifuge. Concentrates from the tests, containing 0.05 to 0.2 vol percent solids, were clarified by sand filter columns to produce solutions of the soluble salts with less than 0.01 vol percent solids. About 700 liters of salt solution and 8 kilograms of washed, dried sludges were separated in the tests. Effects of sludge type, flocculant, flow rates, and batch size were evaluated. Washing and drying of centrifuged sludges were studied, and two types of dryers were tested. Ruthenium volatility during drying was negligible. Washing efficiency was determined by analyses of wash solutions and sludge products

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.

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.

Sludge characterization: the role of physical consistency

Energy Technology Data Exchange (ETDEWEB)

Spinosa, Ludovico; Wichmann, Knut

2003-07-01

The physical consistency is an important parameter in sewage sludge characterization as it strongly affects almost all treatment, utilization and disposal operations. In addition, in many european Directives a reference to the physical consistency is reported as a characteristic to be evaluated for fulfilling the regulations requirements. Further, in many analytical methods for sludge different procedures are indicated depending on whether a sample is liquid or not, is solid or not. Three physical behaviours (liquid, paste-like and solid) can be observed with sludges, so the development of analytical procedures to define the boundary limit between liquid and paste-like behaviours (flowability) and that between solid and paste-like ones (solidity) is of growing interest. Several devices can be used for evaluating the flowability and solidity properties, but often they are costly and difficult to be operated in the field. Tests have been carried out to evaluate the possibility to adopt a simple extrusion procedure for flowability measurements, and a Vicat needle for solidity ones. (author)

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.

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.

Leachability of Heavy Metals from Lightweight Aggregates Made with Sewage Sludge and Municipal Solid Waste Incineration Fly Ash

Science.gov (United States)

Wei, Na

2015-01-01

Lightweight aggregate (LWA) production with sewage sludge and municipal solid waste incineration (MSWI) fly ash is an effective approach for waste disposal. This study investigated the stability of heavy metals in LWA made from sewage sludge and MSWI fly ash. Leaching tests were conducted to find out the effects of MSWI fly ash/sewage sludge (MSWI FA/SS) ratio, sintering temperature and sintering time. It was found that with the increase of MSWI FA/SS ratio, leaching rates of all heavy metals firstly decreased and then increased, indicating the optimal ratio of MSWI fly ash/sewage sludge was 2:8. With the increase of sintering temperature and sintering time, the heavy metal solidifying efficiencies were strongly enhanced by crystallization and chemical incorporations within the aluminosilicate or silicate frameworks during the sintering process. However, taking cost-savings and lower energy consumption into account, 1100 °C and 8 min were selected as the optimal parameters for LWA sample- containing sludge production. Furthermore, heavy metal leaching concentrations under these optimal LWA production parameters were found to be in the range of China’s regulatory requirements. It is concluded that heavy metals can be properly stabilized in LWA samples containing sludge and cannot be easily released into the environment again to cause secondary pollution. PMID:25961800

Assessment and analysis of industrial liquid waste and sludge disposal at unlined landfill sites in arid climate

International Nuclear Information System (INIS)

Al Yaqout, Anwar F.

2003-01-01

Municipal solid waste disposal sites in arid countries such as Kuwait receive various types of waste materials like sewage sludge, chemical waste and other debris. Large amounts of leachate are expected to be generated due to the improper disposal of industrial wastewater, sewage sludge and chemical wastes with municipal solid waste at landfill sites even though the rainwater is scarce. Almost 95% of all solid waste generated in Kuwait during the last 10 years was dumped in five unlined landfills. The sites accepting liquid waste consist of old sand quarries that do not follow any specific engineering guidelines. With the current practice, contamination of the ground water table is possible due to the close location of the water table beneath the bottom of the waste disposal sites. This study determined the percentage of industrial liquid waste and sludge of the total waste dumped at the landfill sites, analyzed the chemical characteristics of liquid waste stream and contaminated water at disposal sites, and finally evaluated the possible risk posed by the continuous dumping of such wastes at the unlined landfills. Statistical analysis has been performed on the disposal and characterization of industrial wastewater and sludge at five active landfill sites. The chemical analysis shows that all the industrial wastes and sludge have high concentrations of COD, suspended solids, and heavy metals. Results show that from 1993 to 2000, 5.14±1.13 million t of total wastes were disposed per year in all active landfill sites in Kuwait. The share of industrial liquid and sludge waste was 1.85±0.19 million t representing 37.22±6.85% of total waste disposed in all landfill sites. Such wastes contribute to landfill leachate which pollutes groundwater and may enter the food chain causing adverse health effects. Lined evaporation ponds are suggested as an economical and safe solution for industrial wastewater and sludge disposal in the arid climate of Kuwait

Radiological study of the sludge generated in a station drinking water treatment

International Nuclear Information System (INIS)

Baeza, A.; Salas, A.; Gragera, J.

2011-01-01

The purification process involves removing the water or at least reducing the legally permitted levels of undesirable substances that become part of the precipitates that originate, called sludge. The importance of the study is given because it will find, in the event that the process effectively reduce its radioactive contents, significant activities of the radionuclides eliminated. In this sense, the concentration of radioactive sludge and, above all, the chemical forms in which these radionuclides are retained condition the danger of the waste produced on the basis of their potential availability. In this study, we analyzed the sludge generated in a water treatment plant that has operated under both routine operation and in conditions designed to optimize the reduction of the radioactive contents for uranium and radium present in the treated water. (Author)

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.

Application of radiation technology to sewage sludge processing: A review

International Nuclear Information System (INIS)

Wang Jianlong; Wang Jiazhuo

2007-01-01

Sewage sludge is unwanted residual solid wastes generated in wastewater treatment and its management is one of the most critical environmental issues of today. The treatment and disposal of sludge contribute a considerable proportion of the cost for running a wastewater treatment plant. The increasing amount of swage sludge and more and more legislative regulation of its disposal have stimulated the need for developing new technologies to process sewage sludge efficiently and economically. One ideal consideration is to recycle it after proper treatment. Radiation technology is regarded to be a promising alternative for its high efficiency in pathogen inactivation, organic pollutants oxidation, odor nuisance elimination and some other characteristics enhancement, which will facilitate the down-stream process of sludge treatment and disposal. Here we present a brief review of application of radiation technology on sewage sludge processing. Some basic information of two currently available irradiation systems and fundamental radiation chemistry are introduced firstly; then the world-wide application of this promising technology is reviewed; various effects of radiation on sludge is discussed in detail; and some concluding remarks are given and some future directions are also proposed

The hydraulic transportation of thickened sludges

African Journals Online (AJOL)

driniev

non-Newtonian sludges (Xu et al., 1993; Spinosa and Lotita, 2001; .... [11]. Analysis and typical applications. Laminar/turbulent transition. For most sewage sludges the ... on Transport and Sedimentation of Solid Particles - Ghent, September.

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.

Combined aerobic and physicochemical treatment of pharmaceutical industry sludge

International Nuclear Information System (INIS)

Asia, Q.I.; Ademoroti, A.M.C.

2005-01-01

Composite samples of sludge obtained from a pharmaceutical factory were analysed for their pollution characteristics. The samples were then treated by integrated aerobic biological and physicochemical methods. The analysis revealed that the BOD and COD of the sludge liquor were high, as well as were the levels of solids concentration, nitrogen, phosphorus and bacterial count. These showed that sludge from this industry had a high pollution potential, and therefore needed treatment before disposal or reuse in other applications. Percentage solids reduction achieved were in the range of 26.1 to 29% of total soluble solids, 26.1 to 33% of suspended solids, and 43 to 52% of volatile solids, BOD and COD reductions were in the range of 96.1 to 98.2% and 96.8 to 98.4% respectively. Ammonia nitrogen reductions in this sludge were about 85.2 to 93.3%. Total nitrogen and phosphorus were also found to be appreciably reduced by the combined aerobic and physicochemical treatment methods. (author)

Effect of different bulking agents on water variation and thermal balance and their respective contribution to bio-generated heat during long-term storage sludge biodrying process.

Science.gov (United States)

Liu, Tiantian; Cui, Chongwei; He, Junguo; Tang, Jian

2018-04-17

Biodrying was first used for the post-treatment of long-term storage sludge with vinasse as bulking agents. The effect of different bulking agents on water and heat variation and their respective contributions to bio-generated heat during storage sludge biodrying were investigated. Three different bulking agents (beer lees and distillers grains, with conventional straw used for comparison) were mixed with storage sludge for biodrying for an 18-day period. The results revealed the treatment with beer lees as bulking agent achieved the best performance with the highest water removal capacity (658 g kg -1 initial water). The extent of organic degradation in the mixture was related to the degradation ability of the bulking agents. The degradation of C- and H-containing materials (e.g., carboxylic acid) accounted for volatile solids (VS) loss. Water and thermal analyses showed that evaporation was the main way of water loss (accounting for 90%), while evaporation heat was the main component of heat consumption (accounting for 56.67-60.62%).The biodegradation of bulking agents contributed a high proportion of the bio-generated heat consumed by water evaporation (82.35-86.67%).

Laboratory testing in-tank sludge washing, summary letter report

International Nuclear Information System (INIS)

Norton, M.V.; Torres-Ayala, F.

1994-09-01

In-tank washing is being considered as a means of pretreating high-level radioactive waste sludges, such as neutralized current acid waste (NCAW) sludge. For this process, the contents of the tank will be allowed to settle, and the supernatant solution will be decanted and removed. A dilute sodium hydroxide/sodium nitrite wash solution will be added to the settled sludge and the tank contents will be mixed with a mixer pump system to facilitate washing of the sludge. After thorough mixing, the mixer pumps will be shut off and the solids will be allowed to re-settle. After settling, the supernatant solution will be withdrawn from the tank, and the wash cycle will be repeated several times with fresh wash solution. Core sample data of double shell tank 241-AZ-101 indicate that settling of NCAW solids may be very slow. A complicating factor is that strong thermal currents are expected to be generated from heat produced by radionuclides in the sludge layer at the bottom of the tank. Additionally, there are concerns that during the settling period (i.e., while mixing pumps and air-lift re-circulators are shut off), the radionuclides may heat the residual interstitial water in the sludge to the extent that violent steam discharges (steam bumping) could occur. Finally, there are concerns that during the washing steps sludge settling may be hindered as a result of the reduced ionic strength of the wash solution. To overcome the postulated reduced settling rates during the second and third washing steps, the use of flocculants is being considered. To address the above concerns and uncertainties associated with in-tank washing, PNL has conducted laboratory testing with simulant tank waste to investigate settling rates, steam bump potential, and the need for and use of flocculating agents

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

A comparison of BNR activated sludge systems with membrane and settling tank solid-liquid separation.

Science.gov (United States)

Ramphao, M C; Wentzel, M C; Ekama, G A; Alexander, W V

2006-01-01

Installing membranes for solid-liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only to the design of the membrane bio-reactor (MBR) BNR system itself, but also to the design approach for the whole wastewater treatment plant (WWTP). In multi-zone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic and aerobic zones (i.e. fixed volume fractions), the mass fractions can be controlled (within a range) with the inter-reactor recycle ratios. This zone mass fraction flexibility is a significant advantage of MBR BNR systems over BNR systems with secondary settling tanks (SSTs), because it allows changing the mass fractions to optimise biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios (fq) in the upper range (fq approximately 2.0), aerobic mass fractions in the lower range (f(maer) settling and long sludge age). However, the volume reduction compared with equivalent BNR systems with SSTs will not be large (40-60%), but the cost of the membranes can be offset against sludge thickening and stabilisation costs. Moving from a flow unbalanced raw wastewater system to a flow balanced (fq = 1) low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes away from extended aeration to include primary sludge stabilisation. The cost of primary sludge treatment then has to be offset against the savings of the increased WWTP capacity.

Effect of potassium ferrate on disintegration of waste activated sludge (WAS).

Science.gov (United States)

Ye, Fenxia; Ji, Haizhuang; Ye, Yangfang

2012-06-15

The activated sludge process of wastewater treatment results in the generation of a considerable amount of excess activated sludge. Increased attention has been given to minimization of waste activated sludge recently. This paper investigated the effect of potassium ferrate oxidation pretreatment on the disintegration of the waste activated sludge at various dosages of potassium ferrate. The results show that potassium ferrate pretreatment disintegrated the sludge particle, resulting in the reduction of total solid content by 31%. The solubility (SCOD/TCOD) of the sludge increased with the increase of potassium ferrate dosage. Under 0.81 g/g SS dosage of potassium ferrate, SCOD/TCOD reached 0.32. Total nitrogen (TN) and total phosphorous (TP) concentrations in the solution all increased significantly after potassium ferrate pretreatment. The sludge particles reduced from 116 to 87 μm. The settleability of the sludge (SVI) was enhanced by 17%, which was due to the re-flocculation by the by-product, Fe(III), during potassium ferrate oxidation and the decrease of the viscosity. From the result of the present investigations, it can be concluded that potassium ferrate oxidation is a feasible method for disintegration of excess activated sludge. Copyright © 2012 Elsevier B.V. All rights reserved.

Sludge, garbage may fuel California sewage plant

Energy Technology Data Exchange (ETDEWEB)

Sieger, R B

1977-01-01

The combustion and pyrolysis of sewage sludge and refuse-derived fuel (RFD) in multiple-hearth furnaces were recommended as a means of generating energy to power the Central Contra Costa Sanitary District's 30 mgd wastewater treatment plant using an off-gas from the pyrolysis process. In a full-scale test, a furnace in Concord, once used for sewage sludge incineration, was operated under O/sub 2/-starved conditions by limiting air addition through the burners and air nozzles, resulting in partial combustion. Using temperature as the controlled variable, the process was regulated to form a fuel gas through composition of the organic feed matter. Just enough fuel gas was combusted to evaporate moisture in the feed solids and furnish heat for the decomposition process. During most of the testing the afterburner was maintained at a temperature > 1400/sup 0/F with pyrolysis gas. At this temperature, automatic ignition of the gas occurred. When the gas generated dropped to a low heat of combustion because of high feed moisture content, the afterburner burner was used to ignite the gas. Some test observations are discussed. Preparation of the solid waste for processing by the use of shredders, air classifiers, and magnetic separators is described.

Alternative treatment for septic tank sludge: co-digestion with municipal solid waste in bioreactor landfill simulators.

Science.gov (United States)

Valencia, R; den Hamer, D; Komboi, J; Lubberding, H J; Gijzen, H J

2009-02-01

Co-disposal of septic tank sludge had a positive effect on the municipal solid waste (MSW) stabilisation process in Bioreactor Landfill simulators. Co-disposal experiments were carried out using the Bioreactor Landfill approach aiming to solve the environmental problems caused by indiscriminate and inadequate disposal of MSW and especially of septic tank sludge. The simulator receiving septic tank sludge exhibited a 200 days shorter lag-phase as compared to the 350 days required by the control simulator to start the exponential biogas production. Additionally, the simulator with septic sludge apparently retained more moisture (>60% w/w), which enhanced the overall conversion of organic matter hence increasing the biogas production (0.60 m3 biogas kg(-1)VS(converted)) and removal efficiency of 60% for VS from the simulator. Alkaline pH values (pH>8.5) did not inhibit the biogas production; moreover it contributed to reduce partially the negative effects of NH(4)(+) (>2 g L(-1)) due to NH(3) volatilisation thus reducing the nitrogen content of the residues. Associated risks and hazards with septage disposal were practically eliminated as total coliform and faecal coliform contents were reduced by 99% and 100%, respectively at the end of the experiment. These results indicate that co-disposal has two direct benefits, including the safe and environmentally sound disposal of septic tank sludge and an improvement of the overall performance of the Bioreactor Landfill by increasing moisture retention and supplying a more acclimatised bacterial population.

Waste management in the meat processing industry: Conversion of paunch and DAF sludge into solid fuel.

Science.gov (United States)

Hamawand, Ihsan; Pittaway, Pam; Lewis, Larry; Chakrabarty, Sayan; Caldwell, Justin; Eberhard, Jochen; Chakraborty, Arpita

2017-02-01

This article addresses the novel dewatering process of immersion-frying of paunch and dissolved air flotation (DAF) sludge to produce high energy pellets. Literature have been analysed to address the feasibility of replacing conventional boiler fuel at meat processing facilities with high energy paunch-DAF sludge pellets (capsules). The value proposition of pelleting and frying this mixture into energy pellets is based on a Cost-Benefit Analysis (CBA). The CBA is based on information derived from the literature and consultation with the Australian Meat Processing Industry. The calorific properties of a mixture of paunch cake solids and DAF sludge were predicted from literature and industry consultation to validate the product. This study shows that the concept of pelletizing and frying paunch is economically feasible. The complete frying and dewatering of the paunch and DAF sludge mixture produces pellets with energy content per kilogram equivalent to coal. The estimated cost of this new product is half the price of coal and the payback period is estimated to be between 1.8 and 3.2years. Further research is required for proof of concept, and to identify the technical challenges associated with integrating this technology into existing meat processing plants. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Two-phase anaerobic digestion of partially acidified sewage sludge: a pilot plant study for safe sludge disposal in developing countries.

Science.gov (United States)

Passio, Luca; Rizzoa, Luigi; Fuchs, Stephan

2012-09-01

The unsafe disposal of wastewater and sludge in different areas of developing countries results in significant environmental pollution, particularly for groundwater, thus increasing the risk of waterborne diseases spreading. In this work, a two-phase anaerobic digestion process for post-treatment of partially acidified sewage sludge was investigated to evaluate its feasibility as a safe sludge disposal system. Pilot tests showed that an effective sludge stabilization can be achieved (total volatile solids content <65%, organic acid concentration <200 mg/L at flow rate = 50 L/d and hydraulic residence time = 18 d) as well as a relative low faecal coliform density (<1000 most probable number per g total solids), showing that land application of the sludge without restrictions is possible according to US Environmental Protection Agency criteria for safe sludge disposal. A biogas production as high as 390 L/d with a 60% methane content by volume was achieved, showing that energy production from biogas may be achieved as well.

Investigation into the use of cement kiln dust in high density sludge (HDS) treatment of acid mine water.

Science.gov (United States)

Mackie, Allison L; Walsh, Margaret E

2015-11-15

The purpose of this study was to investigate the potential to replace lime with cement kiln dust (CKD) in high density sludge (HDS) treatment of acid mine drainage (AMD). The bench-scale study used two water samples: AMD sampled from a lead-zinc mine with high concentrations of iron (Fe), zinc (Zn), and arsenic (As) (Fe/Zn-AMD) and a synthetic AMD solution (Syn-AMD) spiked with ferric sulfate (Fe2(SO4)3). Arsenic was found to be significantly reduced with CKD-HDS treatment of Fe/Zn-AMD compared to lime-HDS treatment, to concentrations below the stringent mine effluent discharge regulation of 0.10 mg As/L (i.e., 0.04 ± 0.02 mg/L). Both CKD- and lime-HDS treatment of the two AMD samples resulted in settled water Fe concentrations above the stringent discharge guideline of 0.3 mg Fe/L. CKD addition in the HDS process also resulted in high settled water turbidity, above typical discharge guidelines of 15 mg TSS/L. CKD-HDS treatment was found to result in significantly improved settled solids (i.e., sludge) quality compared to that generated in the lime-HDS process. HDS treatment with CKD resulted in 25-88% lower sludge volume indices, 2 to 9 times higher % wet solids, and 10 to 20 times higher % dry solids compared to lime addition. XRD and XPS testing indicated that CKD-HDS sludge consisted of mainly CaCO3 and SiO2 with Fe(3+) precipitates attached at particle surfaces. XRD and XPS testing of the lime-HDS generated sludge showed that it consisted of non-crystalline Fe oxides typical of sludge formed from precipitates with a high water concentration. Increased sedimentation rates were also found for CKD (1.3 cm/s) compared to lime (0.3 cm/s). The increased solids loading with CKD addition compared to lime addition in the HDS process was suggested to both promote surface complexation of metal precipitates with insoluble CKD particles and increase compression effects during Type IV sedimentation. These mechanisms collectively contributed to the reduced water content of

High level caves rheological studies of tanks 15H, 42H, and 8F sludge/slurries

International Nuclear Information System (INIS)

Hamm, B.A.

1984-01-01

Samples of sludge were diluted to varying solids loading with salt-supernate, deionized water or pH 12 solution (0.01M NaOH). Rheological and physical property determinations were made. There was not a large change in rhelogical properties of sludge following aluminum dissolution, and a dissolved solids contribution to yield stress was not observed. The tank 15/42 and GIW-79 sludges had aluminum concentrations from 14 to 28 wt %. The tank 8 and GIW-82 sludges had aluminum concentrations from 6 to 8 wt %. The high aluminum sludges showed a more rapid increase in yield stress as a function of insoluble solids than the low aluminum sludges. The synthetic sludge formulation used in the GIW-79 study was a fairly good match for tank 15/42 sludge and the GIW-82 formulation was a fairly food match for tank 8 sludge when comparing yield stress and consistency relationship to insoluble solids. The tank 15/42 results indicate a yield stress of about 200 dynes/cm 2 at 13 wt % insoluble solids. The tank 8 results show a yield stress of about 80 dynes/cm 2 at 19 wt % insoluble solids. The calculational procedure used yields a conservative upper limit on the value of yield stress. For sludge transfer from F to H-area (30 to 50 dynes/cm 2 ), the tank 8 sludge concentration range was 3 to 18 wt % insoluble solids. For transfer from H to S-area (30 to 100 dynes/cm 2 ), the tank 8 concentration range was 3 to 22 wt % insoluble solids and the tank 15/42 range was found to be 6 to 11 wt % insoluble solids

Effect of chemo-mechanical disintegration on sludge anaerobic digestion for enhanced biogas production.

Science.gov (United States)

Kavitha, S; Pray, S Saji; Yogalakshmi, K N; Kumar, S Adish; Yeom, Ick-Tae; Banu, J Rajesh

2016-02-01

The effect of combined surfactant-dispersion pretreatment on dairy waste activated sludge (WAS) reduction in anaerobic digesters was investigated. The experiments were performed with surfactant, Sodium dodecyl sulfate (SDS) in the range of 0.01 to 0.1 g/g suspended solids (SS) and disperser with rpm of 5000-25,000. The COD (chemical oxygen demand) solubilization, suspended solids reduction, and biogas generation increased for an energy input of 7377 kJ/kg total solids (TS) (12,000 rpm, 0.04 g/g SS, and 30 min) and were found to be 38, 32, and 75 %, higher than that of control. The pretreated sludge improved the performance of semicontinuous anaerobic digesters of 4 L working volume operated at four different SRTs (sludge retention time). SRT of 15 days was found to be appropriate showing 49 and 51 % reduction in SS and volatile solids (VS), respectively. The methane yield of the pretreated sample was observed to be 50 mL/g VS removed which was observed to be comparatively higher than the control (12 mL/g VS removed) at optimal SRT of 15 days. To the best of the authors' knowledge, this study is the first to be reported and not yet been documented in literature.

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.

Supercritical water gasification of sewage sludge: gas production and phosphorus recovery

NARCIS (Netherlands)

Acelas Soto, N.Y.; Lopez, D.P.; Brilman, Derk Willem Frederik; Kersten, Sascha R.A.; Kootstra, A.M.J.

2014-01-01

In this study, the feasibility of the gasification of dewatered sewage sludge in supercritical water (SCW) for energy recovery combined with P-recovery from the solid residue generated in this process was investigated. SCWG temperature (400 °C, 500 °C, 600 °C) and residence time (15 min, 30 min, 60

Efficient removal of sulfur hexafluoride (SF6) through reacting with recycled electroplating sludge.

Science.gov (United States)

Zhang, Jia; Zhou, Ji Zhi; Liu, Qiang; Qian, Guangren; Xu, Zhi Ping

2013-06-18

This paper reports that recycled electroplating sludge is able to efficiently remove greenhouse gas sulfur hexafluoride (SF6). The removal process involves various reactions of SF6 with the recycled sludge. Remarkably, the sludge completely removed SF6 at a capacity of 1.10 mmol/g (SF6/sludge) at 600 °C. More importantly, the evolved gases were SO2, SiF4, and a limited amount of HF, with no toxic SOF4, SO2F2, or SF4 being detected. These generated gases can be readily captured and removed by NaOH solution. The reacted solids were further found to be various metal fluorides, thus revealing that SF6 removal takes place by reacting with various metal oxides and silicate in the sludge. Moreover, the kinetic investigation revealed that the SF6 reaction with the sludge is a first-order chemically controlled process. This research thus demonstrates that the waste electroplating sludge can be potentially used as an effective removal agent for one of the notorious greenhouse gases, SF6.

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

Energy uses and recovery in sludge disposal, Part 2

Energy Technology Data Exchange (ETDEWEB)

Jones, J L [Stanford Research Inst., Menlo Park, CA; Bomberger, D C; Lewis, F M

1977-08-01

Capital and operating costs were compared for 3 plant capacities having average dry weather flows of 10, 100, and 500 mgd. Five sludge handling options were considered. They were chemical conditioning with vacuum filtration, low pressure wet air oxidation, high pressure wet air oxidation aerobic and anaerobic digestion, and chemical oxidation with filter press dewatering. The plant sizes considered generated 11.5, 77, and 384 TPD of sludge. High pressure wet air oxidation and aerobic digestion operating costs were the most sensitive to electrical power costs, while the 2 incineration options without heat treatment were the least sensitive. Sludge drying and incineration of a 20% solids cake were the most sensitive to fuel costs, while aerobic and anaerobic digestion were not directly affected. Heat treatment of sludge and dewatering to a 40% cake had the lowest fuel requirements of the 3 incineration options but increased the total plant electric power consumption by >25%. The net Btus consumed were compared. The net consumption was lowest for anaerobic digestion, filter press plus incineration, and heat treatment plus incineration. Excluding heat recovery credit except for steam required in sludge heat treating, these 3 options are still lowest in net Btus consumed.

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.

Pick up of cesium and cobalt activity by oxide sludge in steam generator

International Nuclear Information System (INIS)

Rufus, A.L.; Subramanian, H.; Velmurugan, S.; Santanu Bera; Narasimhan, S.V.; Reddy, G.L.N.; Sankara Sastry, V.

2002-01-01

A pinhole developed near the tube sheet in the steam generator (SG) tube of a pressurised heavy water reactor (PHWR) caused leak of primary coolant containing radioactive contaminants ( 137 Cs, 134 Cs and 60 Co) to the shell side. The sludge collected from the tube sheet region was found to have adsorbed these radionuclides at the high temperature (230-240 deg C) that prevailed in the SG. An attempt has been made to evaluate the quantity of activity retained in the various oxide phases that constitute the sludge and their mode of pick-up. The sludge was characterized by XRD and XPS, which showed the presence of various oxides of iron, copper and nickel along with the silicates of calcium, magnesium and aluminium. Gamma-spectrometry of the sludge confirmed the presence of 137 Cs, 134 Cs and 60 Co to an extent of 7.6, 1.3 and 0.9 μCi/g of sludge, respectively. Selective dissolution in various EDTA based formulations and equilibration with nitric acid and magnesium chloride solutions helped to understand the quantity of activity adsorbed by various constituents of the sludge. It was concluded that a major portion of cesium was picked up by a reversible ion exchange process on various oxide constituents and about 10% by an irreversible specific adsorption process on insoluble silicates. Also, it was proved that 60 Co was specifically adsorbed over the oxides of iron and nickel. (author)

Beneficial reuse of precast concrete industry sludge to produce alkaline stabilized biosolids.

Science.gov (United States)

Gowda, C; Seth, R; Biswas, N

2008-01-01

The precast concrete industry generates waste called concrete sludge during routine mixer tank washing. It is highly alkaline and hazardous, and typically disposed of by landfilling. This study examined the stabilization of municipal sewage sludge using concrete sludge as an alkaline agent. Sewage sludge was amended with 10 to 40% of concrete sludge by wet weight, and 10 and 20% of lime by dry weight of the sludge mix. Mixes containing 30 and 40% of concrete sludge with 20% lime fulfilled the primary requirements of Category 1 and 2 (Canada) biosolids of maintaining a pH of 12 for at least 72 hours. The heavy metals were below Category 1 regulatory limits. The 40% concrete sludge mix was incubated at 52 degrees C for 12 of the 72 hours to achieve the Category 1 and 2 regulations of less than 1000 fecal coliform/g solids. The nutrient content of the biosolids was 8.2, 10 and 0.6 g/kg of nitrogen, phosphorus and potassium respectively. It can be used as a top soil or augmented with potassium for use as fertilizer. The study demonstrates that concrete sludge waste can be beneficially reused to produce biosolids, providing a long-term sustainable waste management solution for the concrete industry.

Rheology of Savannah River Site Tank 51 HLW radioactive sludge

International Nuclear Information System (INIS)

Ha, B.C.

1993-01-01

Savannah River Site (SRS) Tank 51 HLW radioactive sludge represents a major portion of the first batch of sludge to be vitrified in the Defense Waste Processing Facility (DWPF) at SRS. The rheological properties of Tank 51 sludge will determine if the waste sludge can be pumped by the current DWPF process cell pump design and the homogeneity of melter feed slurries. The rheological properties of Tank 51 sludge and sludge/frit slurries at various solids concentrations were measured remotely in the Shielded Cells Operations (SCO) at the Savannah River Technology Center (SRTC) using a modified Haake Rotovisco viscometer system. Rheological properties of Tank 51 radioactive sludge/Frit 202 slurries increased drastically when the solids content was above 41 wt %. The yield stresses of Tank 51 sludge and sludge/frit slurries fall within the limits of the DWPF equipment design basis. The apparent viscosities also fall within the DWPF design basis for sludge consistency. All the results indicate that Tank 51 waste sludge and sludge/frit slurries are pumpable throughout the DWPF processes based on the current process cell pump design, and should produce homogeneous melter feed slurries

Residues of pharmaceutical products in recycled organic manure produced from sewage sludge and solid waste from livestock and relationship to their fermentation level.

Science.gov (United States)

Motoyama, Miki; Nakagawa, Shuhei; Tanoue, Rumi; Sato, Yuri; Nomiyama, Kei; Shinohara, Ryota

2011-07-01

In recent years, sludge generated in sewage treatment plants (STPs) and solid waste from livestock being utilized is useful for circulation of nourishment in farmlands as recycled organic manure (ROM). In this study, we determined the residue levels and patterns of 12 pharmaceutical products generated by human activity in the ROMs produced from human waste sludge (HWS), sewage sludge (SS), cattle manure (CM), poultry manure (PM), swine manure (SM) and horse manure (HM). The kind and number of pharmaceutical products detected in ROMs were different. Fluoroquinolones (FQs) were detected at high levels in HWS and SS samples. In addition, the detection frequency and concentration levels of sulfonamides (SAs) in PM and SM were high. Moreover, high concentrations of chlortetracycline (CTC) were found in only SM. These differences reflect specific adherence adsorption of the pharmaceutical products to different livestock and humans. Moreover, it was found that the concentrations of pharmaceutical products and fermentation levels of ROMs had significant positive correlation (r=0.41, p=0.024). When the fermentation test of ROM was conducted in a rotary fermentor in a lab scale test, the residue levels of pharmaceutical products decreased effectively except carbamazepine (CBZ). The rates of decrease were in the case of tetracyclines (TCs): 85-92%, FQs: 81-100%, erythromycine: 67%, SAs: 79-95%, trimethoprim: 86% and CBZ: 37% by 30 d. Pharmaceutical products that can be decomposed by fermentation process at the lowest impact of residual antibiotic activities may therefore be considered as environmentally friendly medicines. Copyright © 2011 Elsevier Ltd. All rights reserved.

Eco-technological process of glass-ceramic production from galvanic sludge and aluminium slag

Directory of Open Access Journals (Sweden)

Stanisavljević M.

2010-01-01

Full Text Available Methods of purification of waste water which are most commonly used in the Republic of Serbia belong to the type of conventional systems for purification such as chemical oxidation and reduction, neutralization, sedimentation, coagulation, and flocculation. Consequently, these methods generate waste sludge which, unless adequately stabilized, represents hazardous matter. The aluminium slag generated by melting or diecasting aluminium and its alloys is also hazardous matter. In this sense, this paper establishes ecological risk of galvanic waste sludge and aluminium slag and then describes the process of stabilization of these waste materials by means of transformation into a glass-ceramic structure through sintering. The obtained product was analyzed with Fourier Transform Infrared Spectroscopy (FT-IR and X-ray diffraction (XRD. The object of the paper is the eco-technological process of producing glass-ceramics from galvanic sludge and aluminium slag. The aim of the paper is to incorporate toxic metals from galvanic sludge and aluminium slag into the glass-ceramic product, in the form of solid solutions.

Advantages of thermal processes to reduce the amounts of sludge; Interet des procedes thermiques dans la problematique de la reduction et/ou de l'elimination des boues?

Energy Technology Data Exchange (ETDEWEB)

Cretenot, D. [Vivendi Water System, 94 - Saint-Maurice (France); Chauzy, J.; Fernandes, P.; Patria, L. [Anjou Recherche, 78 - Maisons-Laffite (France)

2003-02-01

All the actors in the water field have to face the fate of sludge generated by wastewater treatment. The challenge they have to take up is not only on the good quality of the final effluent but also on the by-products treatment performance. Reduction, stabilization and pasteurization are the key-words in the present trend of sludge treatment., There are many technologies that reduce the final volume of sludge by lowering their dry solids concentration, but only the treatment lines with thermal processes can both reduce the amounts of sludge generated, and also issue sludge that answers to more and more stringent constraints on sanitary quality.

Increased power generation from primary sludge by a submersible microbial fuel cell and optimum operational conditions

DEFF Research Database (Denmark)

Vologni, Valentina; Kakarla, Ramesh; Angelidaki, Irini

2013-01-01

Microbial fuel cells (MFCs) have received attention as a promising renewable energy technology for waste treatment and energy recovery. We tested a submersible MFC with an innovative design capable of generating a stable voltage of 0.250 ± 0.008 V (with a fixed 470 Ω resistor) directly from prima...... prolonged the current generation and increased the power density by 7 and 1.5 times, respectively, in comparison with raw primary sludge. These findings suggest that energy recovery from primary sludge can be maximized using an advanced MFC system with optimum conditions....

Speciation of mercury in sludge solids: washed sludge

Energy Technology Data Exchange (ETDEWEB)

Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Lourie, A. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-10-24

The objective of this applied research task was to study the type and concentration of mercury compounds found within the contaminated Savannah River Site Liquid Waste System (SRS LWS). A method of selective sequential extraction (SSE), developed by Eurofins Frontier Global Sciences1,2 and adapted by SRNL, utilizes an extraction procedure divided into seven separate tests for different species of mercury. In the SRNL’s modified procedure four of these tests were applied to a washed sample of high level radioactive waste sludge.

Microwave enhanced digestion of aerobic SBR sludge | Kennedy ...

African Journals Online (AJOL)

MWs) for improving characteristics of aerobic sequencing batch reactor (SBR) sludge to enhance mesophilic anaerobic digestion. Effects of pretreatment temperature, MW irradiation intensity and solids concentration on sludge characterisation ...

Influence of secondary settling tank performance on suspended solids mass balance in activated sludge systems.

Science.gov (United States)

Patziger, M; Kainz, H; Hunze, M; Józsa, J

2012-05-01

Secondary settling is the final step of the activated sludge-based biological waste water treatment. Secondary settling tanks (SSTs) are therefore an essential unit of producing a clear effluent. A further important function of SSTs is the sufficient thickening to achieve highly concentrated return sludge and biomass within the biological reactor. In addition, the storage of activated sludge is also needed in case of peak flow events (Ekama et al., 1997). Due to the importance of a high SST performance the problem has long been investigated (Larsen, 1977; Krebs, 1991; Takács et al., 1991; Ekama et al., 1997; Freimann, 1999; Patziger et al., 2005; Bürger et al., 2011), however, a lot of questions are still to solve regarding e.g. the geometrical features (inflow, outflow) and operations (return sludge control, scraper mechanism, allowable maximum values of surface overflow rates). In our study we focused on SSTs under dynamic load considering both the overall unsteady behaviour and the features around the peaks, investigating the effect of various sludge return strategies as well as the inlet geometry on SST performance. The main research tool was a FLUENT-based novel mass transport model consisting of two modules, a 2D axisymmetric SST model and a mixed reactor model of the biological reactor (BR). The model was calibrated and verified against detailed measurements of flow and concentration patterns, sludge settling, accompanied with continuous on-line measurement of in- and outflow as well as returned flow rates of total suspended solids (TSS) and water. As to the inlet arrangement a reasonable modification of the geometry could result in the suppression of the large scale flow structures of the sludge-water interface thus providing a significant improvement in the SST performance. Furthermore, a critical value of the overflow rate (q(crit)) was found at which a pronounced large scale circulation pattern develops in the vertical plane, the density current in

Municipal Solid Waste Management: Recycling, Resource Recovery, and Landfills. LC Science Tracer Bullet.

Science.gov (United States)

Meikle, Teresa, Comp.

Municipal solid waste refers to waste materials generated by residential, commercial, and institutional sources, and consists predominantly of paper, glass, metals, plastics, and food and yard waste. Within the definition of the Solid Waste Disposal Act, municipal solid waste does not include sewage sludge or hazardous waste. The three main…

Kinetic model of excess activated sludge thermohydrolysis.

Science.gov (United States)

Imbierowicz, Mirosław; Chacuk, Andrzej

2012-11-01

Thermal hydrolysis of excess activated sludge suspensions was carried at temperatures ranging from 423 K to 523 K and under pressure 0.2-4.0 MPa. Changes of total organic carbon (TOC) concentration in a solid and liquid phase were measured during these studies. At the temperature 423 K, after 2 h of the process, TOC concentration in the reaction mixture decreased by 15-18% of the initial value. At 473 K total organic carbon removal from activated sludge suspension increased to 30%. It was also found that the solubilisation of particulate organic matter strongly depended on the process temperature. At 423 K the transfer of TOC from solid particles into liquid phase after 1 h of the process reached 25% of the initial value, however, at the temperature of 523 K the conversion degree of 'solid' TOC attained 50% just after 15 min of the process. In the article a lumped kinetic model of the process of activated sludge thermohydrolysis has been proposed. It was assumed that during heating of the activated sludge suspension to a temperature in the range of 423-523 K two parallel reactions occurred. One, connected with thermal destruction of activated sludge particles, caused solubilisation of organic carbon and an increase of dissolved organic carbon concentration in the liquid phase (hydrolysate). The parallel reaction led to a new kind of unsolvable solid phase, which was further decomposed into gaseous products (CO(2)). The collected experimental data were used to identify unknown parameters of the model, i.e. activation energies and pre-exponential factors of elementary reactions. The mathematical model of activated sludge thermohydrolysis appropriately describes the kinetics of reactions occurring in the studied system. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

A study of paint sludge deactivation by pyrolysis reactions

Directory of Open Access Journals (Sweden)

Muniz L.A.R.

2003-01-01

Full Text Available The production of large quantities of paint sludge is a serious environmental problem. This work evaluates the use of pyrolysis reaction as a process for deactivating paint sludge that generates a combustible gas phase, a solvent liquid phase and an inert solid phase. These wastes were classified into three types: water-based solvent (latex resin and solvents based on their resins (alkyd and polyurethane. An electrically heated stainless steel batch reactor with a capacity of 579 mL and a maximum pressure of 30 atm was used. Following the reactor, a flash separator, which was operated at atmospheric pressure, partially condensed and separated liquid and gas products. Pressure and temperature were monitored on-line by a control and data acquisition system, which adjusted the heating power supplied to the pyrolysis reactor. Reactions followed an experimental design with two factors (reaction time and temperature and three levels (10, 50 and 90 minutes; 450, 550 and 650degreesC. The response variables were liquid and solid masses and net heat of combustion. The optimal operational range for the pyrolysis process was obtained for each response variable. A significant reduction in total mass of solid waste was obtained.

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

NARCIS (Netherlands)

Quercia, G.; Van der Putten, J.J.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 SiO2 and CaCO3. This sludge deflocculates in aqueous solutions into nano-particles smaller than 1000 nm. Thus, this sludge is potentially hazardous waste when is improperly

Properties of ash generated during sewage sludge combustion: A multifaceted analysis

International Nuclear Information System (INIS)

Magdziarz, Aneta; Wilk, Małgorzata; Gajek, Marcin; Nowak-Woźny, Dorota; Kopia, Agnieszka; Kalemba-Rec, Izabela; Koziński, Janusz A.

2016-01-01

This paper presents chemical properties of sewage sludge ashes required for determining their thermal characteristics. A novel approach, linking selected advanced analytical techniques with FactSage modelling, was developed and applied to obtain new information on deposit formation mechanisms that contribute to fouling and slagging. The mineral matter and fusion temperatures were investigated using a variety of analytical techniques including XRF, ICP-MS, XRD, SEM-EDX and AFT. The slagging and fouling indices were calculated and the sintering properties were predicted. The studied ashes were rich in P_2O_5, CaO, SiO_2 and Fe_2O_3, but their concentrations slightly differed. Phase analyses suggested the existence of calcium and phosphorus as main phases. Thermal behaviour of ashes was studied focusing on the mass loss, temperature peaks and thermic effects with the increasing of temperature up to 1200 °C under air atmosphere. The changes in concentration of ash compounds contributed to differences in ash fusion temperatures. FactSage thermochemical equilibrium calculations were used to predict the amount of liquid slag and solid phases, giving information about slagging properties of ashes. The general conclusion based on experimental studies is that sewage sludge ashes cause the slagging and fouling hazard while they reveal low corrosive effect. - Highlights: • Characterisation of sewage sludge ashes were given. • Transformation of inorganic components was determined using XRD and FTIR. • The ash fusion behaviour of ashes was studied experimentally. • Empirical indices were calculated indicating slagging and fouling propensities. • Thermodynamic equilibrium calculation was used.

Bio gasification of industrial bio waste and sewage sludge-management of biogas quality

Energy Technology Data Exchange (ETDEWEB)

Kymalainen, M.; Lahde, K.; Kaarnakoski, M.; Pirttijarvi, T.; Arnold, M.; Kurola, J.; Kautola, H.

2009-07-01

Bio gasification, i. e. anaerobic digestion, is a well known sustainable option for the management of organic solid wastes and sludges. the produced biogas is a valuable bio fuel to replace fossil fuels in different technical applications (like heating, electricity, transport fuel generation) which in turn determine its quality requirements. (Author)

Synergistic co-digestion of solid-organic-waste and municipal-sewage-sludge: 1 plus 1 equals more than 2 in terms of biogas production and solids reduction.

Science.gov (United States)

Aichinger, Peter; Wadhawan, Tanush; Kuprian, Martin; Higgins, Matthew; Ebner, Christian; Fimml, Christian; Murthy, Sudhir; Wett, Bernhard

2015-12-15

Making good use of existing water infrastructure by adding organic wastes to anaerobic digesters improves the energy balance of a wastewater treatment plant (WWTP) substantially. This paper explores co-digestion load limits targeting a good trade-off for boosting methane production, and limiting process-drawbacks on nitrogen-return loads, cake-production, solids-viscosity and polymer demand. Bio-methane potential tests using whey as a model co-substrate showed diversification and intensification of the anaerobic digestion process resulting in a synergistical enhancement in sewage sludge methanization. Full-scale case-studies demonstrate organic co-substrate addition of up to 94% of the organic sludge load resulted in tripling of the biogas production. At organic co-substrate addition of up to 25% no significant increase in cake production and only a minor increase in ammonia release of ca. 20% have been observed. Similar impacts were measured at a high-solids digester pilot with up-stream thermal hydrolyses where the organic loading rate was increased by 25% using co-substrate. Dynamic simulations were used to validate the synergistic impact of co-substrate addition on sludge methanization, and an increase in hydrolysis rate from 1.5 d(-1) to 2.5 d(-1) was identified for simulating measured gas production rate. This study demonstrates co-digestion for maximizing synergy as a step towards energy efficiency and ultimately towards carbon neutrality. Copyright © 2015 Elsevier Ltd. All rights reserved.

New insights into co-digestion of activated sludge and food waste: Biogas versus biofertilizer.

Science.gov (United States)

Ma, Yingqun; Yin, Yao; Liu, Yu

2017-10-01

This study explored two holistic approaches for co-digestion of activated sludge and food waste. In Approach 1, mixed activated sludge and food waste were first hydrolyzed with fungal mash, and produced hydrolysate without separation was directly subject to anaerobic digestion. In Approach 2, solid generated after hydrolysis of food waste by fungal mash was directly converted to biofertilizer, while separated liquid with high soluble COD concentration was further co-digested with activated sludge for biomethane production. Although the potential energy produced from Approach 1 was about 1.8-time higher than that from Approach 2, the total economic revenue generated from Approach 2 was about 1.9-fold of that from Approach 1 due to high market value of biofertilizer. It is expected that this study may lead to a paradigm shift in biosolid management towards environmental and economic sustainability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solar drying in sludge management in Turkey

Energy Technology Data Exchange (ETDEWEB)

Kamil Salihoglu, Nezih; Pinarli, Vedat; Salihoglu, Guray [Faculty of Engineering and Architecture, Environmental Engineering Department, Uludag University, 16059, Bursa (Turkey)

2007-08-15

Two main wastewater treatment plants in Bursa city in Turkey will start to operate and produce at least 27,000 tons of dry solids per year by the end of 2006. The purpose of this study was to investigate an economical solution to the sludge management problem that Bursa city would encounter. The general trend in Turkey is mechanical dewatering to obtain a dry solid (DS) content of 20%, and liming the mechanically dewatered sludge to reach the legal land filling requirement, 35% DS content. This study recommends limited liming and solar drying as an alternative to only-liming the mechanically dewatered sludge. Open and covered solar sludge drying plants were constructed in pilot scale for experimental purposes. Dry solids and climatic conditions were constantly measured. Faecal coliform reduction was also monitored. The specially designed covered solar drying plant proved to be more efficient than the open plant in terms of drying and faecal coliform reduction. It was found that, if the limited liming and solar drying method was applied after mechanical dewatering instead of only-liming method, the total amount of the sludge to be disposed would be reduced by approximately 40%. This would lead to a reduction in the transportation, handling, and land filling costs. The covered drying system would amortize itself in 4 years. (author)

The sustainable utilization of malting industry wastewater biological treatment sludge

Science.gov (United States)

Vasilenko, T. A.; Svintsov, A. V.; Chernysh, I. V.

2018-01-01

The article deals with the research of using the sludge from malting industry wastewater’s biological treatment and the calcium carbonate slurry as organo-mineral fertilizing additives. The sludge, generated as a result of industrial wastewater biological treatment, is subject to dumping at solid domestic waste landfills, which has a negative impact on the environment, though its properties and composition allow using it as an organic fertilizer. The physical and chemical properties of both wastes have been studied; the recommendations concerning the optimum composition of soil mix, containing the above-mentioned components, have been provided. The phytotoxic effect on the germination capacity and sprouts of cress (Lepidium sativum), barley (Hordéum vulgáre) and oats (Avena sativa) in soil mixes has been determined. The heavy metals and arsenic contents in the sludge does not exceed the allowable level; it is also free of pathogenic flora and helminthes.

Sumi-sludge system; Sumisurajji system

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-04-20

The subject facilities, delivered to Kakegawa City, Shizuoka Prefecture, in December, 1999, are the first machine by the heavy load denitrification processing system adaptive to purifying tank sludge 'Sumi-sludge system'. It enhanced the capacity of 84 kl/day by about 30% to 109 kl/day through the remodeling of the existing facilities. Its major specifications are capacity: 109 kl/day (human wastes 18 kl/day, purifying tank sludge 91 kl/day) and final effluent quality: pH 5.8-8.6, BOD 10 mg/l or less, COD 20 mg/l or less, SS 10 mg/l or less, T-N 10 mg/l or less, T-P 1 mg/l or less, chromaticity 30 degrees or less, coliform group quantity 3,000 pieces/ml or less. It has the following features. (1) Bio-treatment load is reduced by dehydrating human wastes and purifying tank sludge in the prestage of the bio-treatment. (2) Bio-treatment and flocculation separating treatment are integrated. (3) A high-speed flocculation sedimentation tank 'Sumi-thickner' is employed in the solid-liquid separator, enabling stable solid-liquid separation. (translated by NEDO)

Thermo-alkaline pretreatment of waste activated sludge at low-temperatures: effects on sludge disintegration, methane production, and methanogen community structure.

Science.gov (United States)

Kim, Jaai; Yu, Youngseob; Lee, Changsoo

2013-09-01

Low-temperature thermo-alkaline pretreatment of waste activated sludge (WAS) was studied, within the region of 0-0.2 M NaOH and 60-90°C, for the effects of NaOH concentration and temperature on sludge degradability in anaerobic digestion (AD). Significant disintegration of sludge solids (up to 75.6%) and an increase in methane production (up to 70.6%) were observed in the pretreatment trials. Two quadratic models were successfully generated by response surface analysis (R(2)>0.9, pdisintegration (SD) and methane production (MP) respond to changes in the pretreatment conditions. The maximum responses of SD (77.8%) and MP (73.9% increase over the control) were shown at [0.16 M NaOH, 90°C] and [0.10 M NaOH, 73.7°C], respectively. NaOH addition showed a significant influence on the evolution of methanogen community structure during AD, whereas temperature did not. Aceticlastic Methanosaeta and Methanosarcina speceies were likely the major methanogens. Copyright © 2013 Elsevier Ltd. All rights reserved.

Heavy metal extraction from PCB wastewater treatment sludge by sulfuric acid

International Nuclear Information System (INIS)

Kuan, Yu-Chung; Lee, I-Hsien; Chern, Jia-Ming

2010-01-01

Heavy metals contaminated wastewater sludge is classified as hazardous solid waste and needs to be properly treated to prevent releasing heavy metals to the environment. In this study, the wastewater treatment sludge from a printed circuit board manufacturing plant was treated in a batch reactor by sulfuric acid to remove the contained heavy metals. The effects of sulfuric acid concentration and solid to liquid ratio on the heavy metal removal efficiencies were investigated. The experimental results showed that the total and individual heavy metal removal efficiencies increased with increasing sulfuric acid concentration, but decreased with increasing solid to liquid ratio. A mathematical model was developed to predict the residual sludge weights at varying sulfuric concentrations and solid to liquid ratios. The trivalent heavy metal ions, iron and chromium were more difficult to be removed than the divalent ions, copper, zinc, nickel, and cadmium. For 5 g/L solid to liquid ratio, more than 99.9% of heavy metals can be removed from the sludge by treating with 0.5 M sulfuric acid in 2 h.

Rheology of Savannah River Site Tank 42 radioactive sludges. Revision 1

International Nuclear Information System (INIS)

Ha, B.C.; Bibler, N.E.

1995-01-01

Knowledge of the rheology of the radioactive sludge slurries at the Savannah River Site (SRS) is necessary in order to ensure that they can be retrieved from waste tanks and processed for final disposal. At Savannah River Site (SRS), Tank 42 sludge represents one of the first HLW radioactive sludges to be vitrified in the Defense Waste Processing Facility (DWPF). The rheological properties of unwashed Tank 42 sludge slurries at various solids concentrations were measured remotely in the Shielded Cells at the Savannah River Technology Center (SRTC) using a modified Haake Rotovisco viscometer. Rheological properties of Tank 42 radioactive sludge were measured as a function of weight percent total solids to ensure that the first DWPF radioactive sludge batch can be pumped and processed in the DWPF with the current design bases. The yield stress and consistency of the sludge slurries were determined by assuming a Bingham plastic fluid model

Benefits of integrating chemical and mechanical cleaning processes for steam generator sludge removal

International Nuclear Information System (INIS)

Varrin, R.D.; Ferriter, A.M.; Oliver, T.W.; Le Surf, J.E.

1992-01-01

This paper discusses the benefits of performing in-bundle tubesheet lancing in conjunction with chemical cleaning of PWR and PHWR steam generators in which a hard sludge pile is known to exist. The primary benefits of in-bundle lancing are to: (1) increase the exposed area of the sludge pile by cutting furrows in the surface thereby enhancing dissolution of sludge, (2) reduce the volume of solvents required since material removed by lancing does not have to be dissolved chemically, (3) improve rinsing and removal of residual solvent between iron and copper dissolution steps, and (4) allow for verification of process effectiveness by providing high quality in-bundle visual inspection. The reduction in solvent volumes can lead to a significant reduction in solvent costs and waste processing. A case study which includes an economic evaluation for a combined chemical and mechanical cleaning shows a potential cost saving of up to US$ 300,000 over use of chemical cleaning alone. 14 refs., 2 tabs., 2 figs

Siloxane removal and sludge disintegration using thermo-alkaline treatments with air stripping prior to anaerobic sludge digestion

International Nuclear Information System (INIS)

Oshita, Kazuyuki; Fujime, Motochika; Takaoka, Masaki; Fujimori, Takashi; Appels, Lise; Dewil, Raf

2015-01-01

Highlights: • Siloxanes hamper the energy-use of anaerobic digestion biogas. • D5 siloxane was considered as target compound in this study. • The treatment removed 80% of D5 in sewage sludge at 55 °C and 135 g-NaOH kg −1 -VTS. • D5 removal and the disintegration of VSS in the sludge were correlated. • At the optimal conditions, the costs of anaerobic digestion were notably diminished. - Abstract: A thermo-alkaline treatment with air stripping was applied before anaerobic sludge digestion for both siloxane removal and sludge disintegration. The treatment was expected to increase the amount of biogas produced and to reduce the amount of siloxane in the gas. Adding sodium hydroxide (NaOH) to the sludge improved the removal of siloxane from the sludge, with approximately 90% of the siloxane removed to the gas phase using a thermo-alkaline treatment. Over 80% of decamethylcyclopentasiloxane (D5) could be removed under the following conditions: 55 °C treatment temperature, 135 g-NaOH kg −1 volatile total solids (VTS), and 0.5 L min −1 air-stripping rate. The disintegration ratio of volatile suspended solids (VSS) in the sludge was correlated with the D5 removal ratio. Because most of the siloxane was adsorbed to, or was contained in the VSS, the siloxane removal ratio increased with VSS disintegration. Finally, the energy consumption and operational costs of this system were evaluated for several scenarios. Thermo-alkaline treatment at the indicated operational conditions had the lowest operating costs for a 400 m 3 day −1 anaerobic sludge digestion system

Solid State Culture Conditions for Composting Sewage Sludge

Directory of Open Access Journals (Sweden)

N.A. Kabbashi

2012-10-01

Full Text Available Composting is applied to treat sewage sludge from treatment plants to enhance its quality and suitability for agricultural use. In this work the optimal conditions for composting sewage sludge from domestic wastewater treatment plants in a horizontal drum bioreactor (HDB were investigated. This study investigated the physico-chemical conditions affecting the use of filamentous fungi in composting. The average number of faecal coliforms was 2.3  107 bacteria/g waste dry weight at the beginning of the composting process, and decreased considerably to 8.2  103, 8.1  103, 8.5  103, 8.0  103,and 8.4  103 bacteria/g, respectively for experiments T1 to T5. This decrease was presumably the result of raising temperature. The phase of hygienisation was marked by a very significant decrease in the number of E. coli cells (1.8  107, to 3.7  103, 3.8  103, 3.3  103, 3.2  103, and 3.6  103 bacteria/g for T1 to T5 experiments, respectively: A second aspect was the investigation of a possible reduction of hazardous pollutants.  The highest concentration was for Fe and the lowest for Pb, showing that Fe is the most loosely bound to the sewage sludge organic matrix and Pb the most strongly bound, the Cd reduction by composting was more than 50%.Keywords: Sewage sludge, compost, horizontal drum bioreactor, hazardous.

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

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

NARCIS (Netherlands)

Quercia Bianchi, G.; van der Putten, J.J.G.; Brouwers, H.J.H.; Uzoegbo, H.C.; Schmidt, W.

2013-01-01

Waste sludge, a solid recovered from wastewater of photovoltaic-industries, composes of agglomerates of nano-particles like SiO2 and CaCO3. This sludge deflocculates in aqueous solutions into nano-particles smaller than 1000 nm. Thus, this sludge is potentially hazardous waste when is improperly

Actual Waste Demonstration of the Nitric-Glycolic Flowsheet for Sludge Batch 9 Qualification

Energy Technology Data Exchange (ETDEWEB)

Newell, J. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pareizs, J. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martino, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Reboul, S. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coleman, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Johnson, F. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-09-01

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs qualification testing to demonstrate that the sludge batch is processable. Testing performed by the Savannah River National Laboratory has shown glycolic acid to be effective in replacing the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the catalytic generation of hydrogen and ammonia which could allow purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allows for effective rheology adjustment, and is favorable with respect to melter flammability. In order to implement the new flowsheet, SRAT and SME cycles, designated SC-18, were performed using a Sludge Batch (SB) 9 slurry blended from SB8 Tank 40H and Tank 51H samples. The SRAT cycle involved adding nitric and glycolic acids to the sludge, refluxing to steam strip mercury, and dewatering to a targeted solids concentration. Data collected during the SRAT cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. The SME cycle demonstrated the addition of glass frit and the replication of six canister decontamination additions. The demonstration concluded with dewatering to a targeted solids concentration. Data collected during the SME cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. Slurry and condensate samples were collected for subsequent analysis

Utilisation of fly ash for the management of heavy metal containing primary chemical sludge generated in a leather manufacturing industry

Energy Technology Data Exchange (ETDEWEB)

Sekaran, G.; Rao, B.P.; Ghanamani, A.; Rajamani, S. [Central Leather Research Institute, Chennai (India). Dept. of Environmental Technology

2003-07-01

The present study aims at disposal of primary chemical sludge generated in the tanning industry by solidification and stabilization process using flyash generated from thermal power plant along with binders and also on evaluating the leachability of heavy metal from the solidified product. The primary chemical sludge containing heavy metals iron and chromium were obtained from a garment leather manufacturing company at Chennai in India. The sludge was dried in open environment and it was powdered to fine size in a grinder. Binding increases stabilization of heavy metal in calcined sludge with refractory binders such as clay, fly ash, lime and ordinary Portland cement. Fly ash can be considered as the additional binder for producing stronger bricks, with high metal fixation efficiency, and minimum rate of removal of heavy metal and minimum diffusion co-efficient. 15 refs., 5 figs., 5 tabs.

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...

Effect of bioleaching on hydrogen-rich gas production by steam gasification of sewage sludge

International Nuclear Information System (INIS)

Li, Hanhui; Chen, Zhihua; Huo, Chan; Hu, Mian; Guo, Dabin; Xiao, Bo

2015-01-01

Highlights: • Bioleaching can modify the physicochemical property of sewage sludge. • The enhancement is mainly hydrogen. • Bioleaching can enhance the gas production in gasification of sewage sludge. • Study provides an insight for future application of bioleached sewage sludge. - Abstract: Effect of bioleaching on hydrogen-rich gas production by steam gasification of sewage sludge was carried out in a lab-scale fixed-bed reactor. The influence of sewage sludge solids concentrations (6–14% (w/v) in 2% increments) during the bioleaching process and reactor temperature (600–900 °C in 100 °C increments) on gasification product yields and gas composition were studied. Characterization of samples showed that bioleaching treatment, especially in 6% (w/v) sludge solids concentration, led to metal removal effectively and modifications in the physicochemical property of sewage sludge which was favored for gasification. The maximum gas yield (49.4%) and hydrogen content (46.4%) were obtained at 6% (w/v) sludge solids concentration and reactor temperature of 900 °C. Sewage sludge after the bioleaching treatment may be a feasible feedstock for hydrogen-rich gas product.

Comment on "Synergistic co-digestion of solid-organic-waste and municipal-sewage-sludge: 1 plus 1 equals more than 2 in terms of biogas production and solids reduction" [Water Research 87, 416-423].

Science.gov (United States)

Insam, Heribert; Markt, Rudolf

2016-05-15

Co-digestion of organic waste and sewage sludge enhances biogas production and reduces the mass of remaining solids. This phenomenon of enhanced organic matter decomposition by adding labile substrate is known from other habitats like soils and sediments where it is called priming effect. It is thus suggested to adopt the term priming effect also in environmental biotechnology, and in particular for biomethanisation of wastewater sludges by the addition of energy-rich co-substrates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of nanoparticles on the polymer-conditioned dewatering of wastewater sludges.

Science.gov (United States)

Boyle, N J; Evans, G M

2013-01-01

The effect of using small-scale, high surface area, nanoparticles to supplement polymer-conditioned wastewater sludge dewatering was investigated. Aerobically digested sludge and waste activated sludge sourced from the Hunter Valley, NSW, Australia, were tested with titanium dioxide nanoparticles. The sludge samples were dosed with the nanoparticles in an attempt to adsorb a component of the charged biopolymer surfactants present naturally in sludge. The sludge was conditioned with a cationic polymer. The dewatering characteristics were assessed by measuring the specific resistance to filtration through a modified time-to-filter testing apparatus. The solids content of the dosed samples was determined by a mass balance and compared to the original solids content in the activated sludge. Test results indicated that nanoparticle addition modified the structure of the sludge and provided benefits in terms of the dewatering rate. The samples dosed with nanoparticles exhibited faster water removal, indicating a more permeable filter cake and hence more permeable sludge. A concentration of 2-4% nanoparticles was required to achieve a noticeable benefit. As a comparison, the sludge samples were also tested with a larger particle size, powdered activated carbon (PAC). It was found that the PAC did provide some minor benefits to sludge dewatering but was outperformed by the nanoparticles. The solids content of the final sludge was increased by a maximum of up to 0.6%. The impact of the order sequence of particles and polymer was also investigated. It was found that nanoparticles added before polymer addition provided the best dewatering performance. This outcome was consistent with current theories and previous research through the literature. An economic analysis was undertaken to confirm the viability of the technology for implementation at a full-scale plant. It was found that, currently, this technology is unlikely to be favourable unless the nanoparticles can be

SLUDGE WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS FOR SLUDGE BATCH 6 QUALIFICATION

Energy Technology Data Exchange (ETDEWEB)

Pareizs, J.; Pickenheim, B.; Bannochie, C.; Billings, A.; Bibler, N.; Click, D.

2010-10-01

below the DWPF target with 750 g of steam per g of mercury. However, rheological properties did not improve and were above the design basis. Hydrogen generation rates did not exceed DWPF limits during the SRAT and Slurry Mix Evaporator (SME) cycles. However, hydrogen generation during the SRAT cycle approached the DWPF limit. The glass fabricated with the Tank 51 SB6 SME product and Frit 418 was acceptable with respect to chemical durability as measured by the Product Consistency Test (PCT). The PCT response was also predictable by the current durability models of the DWPF Product Composition Control System (PCCS). It should be noted, however, that in the first attempt to make glass from the SME product, the contents of the fabrication crucible foamed over. This may be a result of the SME product's REDOX (Reduction/Oxidation - Fe{sup 2+}/{Sigma}Fe) of 0.08 (calculated from SME product analytical results). The following are recommendations drawn from this demonstration. In this demonstration, at the request of DWPF, SRNL caustic boiled the SRAT contents prior to acid addition to remove water (to increase solids concentration). During the nearly five hours of caustic boiling, 700 ppm of antifoam was required to control foaming. SRNL recommends that DWPF not caustic boil/concentrate SRAT receipt prior to acid addition until further studies can be performed to provide a better foaming control strategy or a new antifoam is developed for caustic boiling. Based on this set of runs and a recently completed demonstration with the SB6 Waste Acceptance Product Specifications (WAPS) sample, it is recommended that DWPF not add formic acid at the design addition rate of two gallons per minute for this sludge batch. A longer acid addition time appears to be helpful in allowing slower reaction of formic acid with the sludge and possibly decreases the chance of a foam over during acid addition.

Acid extraction of molybdenum, nickel and cobalt from mineral sludge generated by rainfall water at a metal recycling plant.

Science.gov (United States)

Vemic, M; Bordas, F; Guibaud, G; Comte, S; Joussein, E; Lens, P N L; Van Hullebusch, E D

2016-01-01

This study investigated the leaching yields of Mo, Ni and Co from a mineral sludge of a metal recycling plant generated by rainfalls. The investigated mineral sludge had a complex heterogeneous composition, consisting of particles of settled soil combined with metal-bearing particles (produced by catalysts, metallic oxides and battery recycling). The leaching potential of different leaching reagents (stand-alone strong acids (HNO3 (68%), H2SO4 (98%) and HCl (36%)) and acid mixtures (aqua regia (nitric + hydrochloric (1:3)), nitric + sulphuric (1:1) and nitric + sulphuric + hydrochloric (2:1:1)) was investigated at changing operational parameters (solid-liquid (S/L) ratio, leaching time and temperature), in order to select the leaching reagent which achieves the highest metal leaching yields. Sulphuric acid (98% H2SO4) was found to be the leachant with the highest metal leaching potential. The optimal leaching conditions were a three-stage successive leaching at 80 °C with a leaching time of 2 h and S/L ratio of 0.25 g L(-1). Under these conditions, the achieved mineral sludge sample leaching yields were 85.5%, 40.5% and 93.8% for Mo, Ni and Co, respectively. The higher metal leaching potential of H2SO4 in comparison with the other strong acids/acid mixtures is attributed to the fact that H2SO4 is a diacidic compound, thus it has more H(+) ions, resulting in its stronger oxidizing power and corrosiveness.

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

NARCIS (Netherlands)

Quercia Bianchi, G.; van der Putten, J.J.G.; Husken, 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 SiO2 and CaCO3. This sludge deflocculates in aqueous solutions into nano-particles smaller than 1 µm. Thus, this sludge constitutes a potentially hazardous waste when it is

Legislation concerning the energy reuse of sludge from waste water treatment plant in the region of Slovenia

Energy Technology Data Exchange (ETDEWEB)

Mislej, V. (Vodovod-Kanalizacija, Ljubljana (Slovenia)), Email: vmislej@vo-ka.si; Grilc, V. (National Inst. of Chemistry, Ljubljana (Slovenia)), Email: viktor.grilc@ki.si

2009-07-01

The legislation on waste management in Slovenia was markedly renovated in the year 2008. The main changes were related to the treatment of biologically degradable wastes, which was extended to the energy-from-waste option. New regulations in Slovenia have set criteria on which wastes can be processed and transformed into a solid recovered fuel and the conditions concerning its quality and use. The legislation also outlines other process conditions for placing sewage sludge on the market as a secondary solid fuel and its application in various thermal processes. Sewage sludge represents the largest share of wastes. generated at biological wastewater treatment plants (BWWTP). In fresh form it is formed as excess active sludge formed during biological treatment of municipal wastewater and may be consecutive stabilized by an aerobic or anaerobic process. Anaerobic stabilization (digestion)of the raw gravity thickened sludge, followed by mechanical and thermal dehydration transform the fresh sludge into stable dry granules. In this form it is suitable for marketing and utilization in thermal processes. The main problems may be low calorific value and relative high metals content (especially mercury) and sulphur. Sulphur and cadmium are not among the limiting parameters of the noted technical specification for alternative fuels, so the new regulation in Slovenia will be appealed. (orig.)

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.

Proceedings of steam generator sludge deposition in recirculating and once through steam generator upper tube bundle and support plates

International Nuclear Information System (INIS)

Baker, R.L.; Harvego, E.A.

1992-01-01

The development of remedial measures of shot peening have given nuclear utilities viable measures to address primary water stress corrosion cracking to extend steam generator life. The nuclear utility industry is now faced with potential replacement of steam generators in nuclear power plants due to stress corrosion cracking and intergranular attach in crevice locations on the secondary side of steam generators at tube support plates and at the crevice at the top of the tube sheet. Significant work has been done on developing and understanding of the effects of sludge buildup on the corrosion process at these locations. This session was envisioned to provide a forum for the development of an understanding of the mechanisms which control the transport and deposition of sludge on the secondary side of steam generators. It is hoped that this information will aid utilities in monitoring the progression of fouling of these crevices by further knowledge in where to look for the onset of support plate crevice fouling. An understanding of the progression of fouling from upper tube support plates to those lower in the steam generator where higher temperatures cause the corrosion process to initiate first can aid the nuclear utility industry in developing remedial measures for this condition and in providing a forewarning of when to apply such remedial measures

Comparison between thermo balance and classic gravimetric method for determination of suspended solids in sludge from wastewater treatment plant

International Nuclear Information System (INIS)

Bruzzone, E.

2009-01-01

In this paper two methods for determination of suspended solids in sludge from wastewater treatment plants (activated, thickened and dry, in a range from 0.1 to 20-25%) are compared. Results are similar from statistic point of view between classic gravimetric method and thermo balance method. However the later seems better for its rapid and easy execution. [it

A computational technique for turbulent flow of wastewater sludge.

Science.gov (United States)

Bechtel, Tom B

2005-01-01

A computational fluid dynamics (CFD) technique applied to the turbulent flow of wastewater sludge in horizontal, smooth-wall, circular pipes is presented. The technique uses the Crank-Nicolson finite difference method in conjunction with the variable secant method, an algorithm for determining the pressure gradient of the flow. A simple algebraic turbulence model is used. A Bingham-plastic rheological model is used to describe the shear stress/shear rate relationship for the wastewater sludge. The method computes velocity gradient and head loss, given a fixed volumetric flow, pipe size, and solids concentration. Solids concentrations ranging from 3 to 10% (by weight) and nominal pipe sizes from 0.15 m (6 in.) to 0.36 m (14 in.) are studied. Comparison of the CFD results for water to established values serves to validate the numerical method. The head loss results are presented in terms of a head loss ratio, R(hl), which is the ratio of sludge head loss to water head loss. An empirical equation relating R(hl) to pipe velocity and solids concentration, derived from the results of the CFD calculations, is presented. The results are compared with published values of Rhl for solids concentrations of 3 and 6%. A new expression for the Fanning friction factor for wastewater sludge flow is also presented.

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.

Biological sulphate reduction with primary sewage sludge in an ...

African Journals Online (AJOL)

2009-07-31

Jul 31, 2009 ... The success of the UASB reactor depends largely on the settling properties and stability of the sludge bed which comprises the anaerobic active biomass. The solid-liquid separation behaviour of the sludge bed in 2 UASB reactors (R1 at 35oC and. R2 at 20oC) fed with primary sewage sludge and sulphate ...

Biological sulphate reduction with primary sewage sludge in an ...

African Journals Online (AJOL)

The success of the UASB reactor depends largely on the settling properties and stability of the sludge bed which comprises the anaerobic active biomass. The solid-liquid separation behaviour of the sludge bed in 2 UASB reactors (R1 at 35oC and R2 at 20oC) fed with primary sewage sludge and sulphate was investigated ...

Electricity generation using chocolate industry wastewater and its treatment in activated sludge based microbial fuel cell and analysis of developed microbial community in the anode chamber.

Science.gov (United States)

Patil, Sunil A; Surakasi, Venkata Prasad; Koul, Sandeep; Ijmulwar, Shrikant; Vivek, Amar; Shouche, Y S; Kapadnis, B P

2009-11-01

Feasibility of using chocolate industry wastewater as a substrate for electricity generation using activated sludge as a source of microorganisms was investigated in two-chambered microbial fuel cell. The maximum current generated with membrane and salt bridge MFCs was 3.02 and 2.3 A/m(2), respectively, at 100 ohms external resistance, whereas the maximum current generated in glucose powered MFC was 3.1 A/m(2). The use of chocolate industry wastewater in cathode chamber was promising with 4.1 mA current output. Significant reduction in COD, BOD, total solids and total dissolved solids of wastewater by 75%, 65%, 68%, 50%, respectively, indicated effective wastewater treatment in batch experiments. The 16S rDNA analysis of anode biofilm and suspended cells revealed predominance of beta-Proteobacteria clones with 50.6% followed by unclassified bacteria (9.9%), alpha-Proteobacteria (9.1%), other Proteobacteria (9%), Planctomycetes (5.8%), Firmicutes (4.9%), Nitrospora (3.3%), Spirochaetes (3.3%), Bacteroides (2.4%) and gamma-Proteobacteria (0.8%). Diverse bacterial groups represented as members of the anode chamber community.

Method and apparatus for removal of residual sludge from a nuclear steam generator

International Nuclear Information System (INIS)

Lahoda, E.J.; Echardt, D.A.

1987-01-01

This patent describes a method for removing sludge deposits from the tube sheet of a nuclear steam generator vessel to which is connected a bundle of parallel heat exchange tubes arranged in parallel rows separated by lanes and parallel columns separated by channels. The method includes the steps of: directing a cleaning stream of sequentially advancing a lance past the channels one channel at a time, fluid along a first channel for dislodging sludge deposits and moving them toward the periphery of the bundle of tubes, substantially simultaneously directing a barrier stream of fluid from the lance in substantially the same direction as the cleaning stream. Stream continues along a second channel spaced from the first channel by at least two columns of tubes with no streams directed from the lance along any other channel between the first and second channels to prevent the dislodged sludge from being moved past the barrier stream into previously cleaned channels. Each of the streams has an axis immovable with respect to the other stream in directions parallel to the tube sheet and having a width in directions perpendicular to the axis and parallel to the tube sheet less than the width of the associated channel along which the stream is directed. This removes sludge-loaded fluid from the periphery of the bundle of tubes

Sludge Lancing and Visual Inspection of Steam Generator for KORI Nuclear Power Plant Unit 3

Energy Technology Data Exchange (ETDEWEB)

Jeong, Woo-Tae [Korea Hydro and Nuclear Power Co. Ltd. Central Research Institute, Daejeon(Korea, Republic of); Kim, Sang-Tae; Hong, Jae-Yung; Jeong, Yun-Soon [Sae-An Engineering Corporation, Seoul (Korea, Republic of)

2015-05-15

Annulus, tube-lane, and in-bundle area of the steam generators were searched for possible foreign objects. No new foreign objects were found. Two foreign objects which were found during previous outage were impossible to remove. Mock-up training before the operation was helpful to finish the service as scheduled. Sludge lancing of the three steam generators was made using FOLAS-I lancing system. FOSAR operations were done using video probe and special tools of Sae-An Engineering Cooperation. The weight of sludge removed from SG 'A', 'B', and 'C' was 177kg, 134kg, 117kg respectively. Bag filters for and cartridge filters consumed for SG 'A', 'B', and 'C' was (53,414), (75,243), and (61,171) respectively. Foreign object search operation for the annulus, the tube lane, and in-bundle area of the steam generators found nothing. Retrieval of the two remaining foreign objects from the previous outage was tried but failed.

Sludge Lancing and Visual Inspection of Steam Generator for KORI Nuclear Power Plant Unit 3

International Nuclear Information System (INIS)

Jeong, Woo-Tae; Kim, Sang-Tae; Hong, Jae-Yung; Jeong, Yun-Soon

2015-01-01

Annulus, tube-lane, and in-bundle area of the steam generators were searched for possible foreign objects. No new foreign objects were found. Two foreign objects which were found during previous outage were impossible to remove. Mock-up training before the operation was helpful to finish the service as scheduled. Sludge lancing of the three steam generators was made using FOLAS-I lancing system. FOSAR operations were done using video probe and special tools of Sae-An Engineering Cooperation. The weight of sludge removed from SG 'A', 'B', and 'C' was 177kg, 134kg, 117kg respectively. Bag filters for and cartridge filters consumed for SG 'A', 'B', and 'C' was (53,414), (75,243), and (61,171) respectively. Foreign object search operation for the annulus, the tube lane, and in-bundle area of the steam generators found nothing. Retrieval of the two remaining foreign objects from the previous outage was tried but failed

Characterization of tank 51 sludge samples (HTF-51-17-44/ HTF-51-17-48) in support of sludge batch 10 processing

Energy Technology Data Exchange (ETDEWEB)

Oji, L. N. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-08-17

The Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) Engineering (SRR-E) to provide sample characterization and analyses of Tank 51 sludge samples in support of Sludge Batch (SB) 10. The two Tank 51 sludge samples were sampled and delivered to SRNL in May of 2017. These two tank 51 sludge samples were combined into one composite sample and analyzed for corrosion controls analytes, select radionuclides, chemical elements, density and weight percent total solids and aluminum hydroxides (gibbsite and boehmite) by x-ray diffraction.

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

SLUDGE WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS FOR SLUDGE BATCH 5 QUALIFICATION

Energy Technology Data Exchange (ETDEWEB)

Pareizs, J; Cj Bannochie, C; Damon Click, D; Dan Lambert, D; Michael Stone, M; Bradley Pickenheim, B; Amanda Billings, A; Ned Bibler, N

2008-11-10

Sludge Batch 5 (SB5) is predominantly a combination of H-modified (HM) sludge from Tank 11 that underwent aluminum dissolution in late 2007 to reduce the total mass of sludge solids and aluminum being fed to the Defense Waste Processing Facility (DWPF) and Purex sludge transferred from Tank 7. Following aluminum dissolution, the addition of Tank 7 sludge and excess Pu to Tank 51, Liquid Waste Operations (LWO) provided the Savannah River National Laboratory (SRNL) a 3-L sample of Tank 51 sludge for SB5 qualification. SB5 qualification included washing the sample per LWO plans/projections (including the addition of a Pu/Be stream from H Canyon), DWPF Chemical Process Cell (CPC) simulations, waste glass fabrication (vitrification), and waste glass chemical durability evaluation. This report documents: (1) The washing (addition of water to dilute the sludge supernatant) and concentration (decanting of supernatant) of the Tank 51 qualification sample to adjust sodium content and weight percent insoluble solids to Tank Farm projections. (2) The performance of a DWPF CPC simulation using the washed Tank 51 sample. This includes a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid is added to the sludge to destroy nitrite and remove mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit is added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters for the CPC processing were based on work with a non radioactive simulant. (3) Vitrification of a portion of the SME product and Product Consistency Test (PCT) evaluation of the resulting glass. (4) Rheology measurements of the initial slurry samples and samples after each phase of CPC processing. This work is controlled by a Task Technical and Quality Assurance Plan (TTQAP) , and analyses are guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R

A new electrokinetic technology for revitalization of oily sludge

Energy Technology Data Exchange (ETDEWEB)

Habibi, S.

2004-07-01

Oily sludge is a mixture of hydrocarbons, water, metals and suspended fine solids. The petroleum industry is faced with the challenge of handling large volumes of such sludge whose properties depend on the nature of the crude oil, the processing capacity, the down-stream capacities and the design of effluent treatment plants. The management of oily sludge is both complicated and costly due to its complex composition. For that reason, this study developed a method to improve the separation of phases to allow for greater reuse of oily sludge. The study focused on the use of electrokinetic phenomena for the remediation of oily sludge. An amphoteric surfactant was used to evaluate the effect of surfactant on the electrokinetic mobilization or organic contaminants in oily sludge. A series of electrokinetic cell tests were conducted with varying electrical potentials for a 32 day period. Electrical parameters were measured on a daily basis and samples were collected at specific time intervals for UV/VIS and FTIR analysis. The study involved a range of electrokinetic processes such as electrocoagulation, electro-coalescence, desorption, electrophoresis and electro-osmosis. Study results were used to evaluate the thermodynamics of the proposed process and new theories on the behaviour of colloidal components of oily sludge were derived. The study indicated that there is an excellent separation of water, hydrocarbon and solid phases. Since the recovered solid phase has a high hydrocarbon content, it can be recycled for other processes. Some of the volatile hydrocarbons that were released during the process can also be captured and burned as a fuel. The separated water had a low concentration of hydrocarbon and could be sent to wastewater treatment plants.

[Effect of microbial nutrient concentration on improvement of municipal sewage sludge dewaterability through bioleaching].

Science.gov (United States)

Song, Yong-wei; Liu, Fen-wu; Zhou, Li-xiang

2012-08-01

In this study, shaking flask batch experiments and practical engineering application tests were performed to investigate the effect of microbial nutrient concentration on the dewaterability of municipal sewage sludge with 2%, 3%, 4% and 5% solid contents via bioleaching. Meanwhile, the changes of pH value and the utilization efficiency of microbial nutrients during bioleaching were analyzed in this study. The results showed that the pH value decreased gradually at the beginning and then maintained a stable state in the treatments with different solid contents, and the nutrients were completely used up by the microorganisms after 2 days of bioleaching. It was found that the SRF of 2%, 3%, 4%, 5% sludges decreased quickly and then rose gradually with the extension of bioleaching time. In addition, the higher solid content the greater the increase. It was determined that the optimum microbial nutrient dosage for sludge with solid content of 2%, 3%, 4% and 5% were 3.0 g x L(-1), 4.5 g x L(-1), 8.3 g x L(-1) and 12.8 g x L(-1) respectively. At this point, the lowest SRF of sludge with each solid content were 0.61 x 10(12) m x kg(-1), 1.22 x 10(12) m x kg(-1), 3.09 x 10(12) m x kg(-1) and 4.83 x 10(12) m x kg(-1), respectively. Through the engineering application, it was showed that diluting the solid content of sewage sludge from 5% to 3% before bioleaching was feasible. It could not only improve the dewaterability of bioleached sewage sludge (the SRF declined from 3.29 x 10(12) m x kg(-1) to 1.10 x 10(12) m x kg(-1)), but also shorten the sludge nutrient time (shortened from 4 days to 2.35 days) and reduce the operation costs. Therefore, the results of this study have important significance for the engineering application of bioleaching of municipal sewage sludge with high solid content.

PILOT-SCALE TESTING OF THE SUSPENSION OF MST, CST, AND SIMULATED SLUDGE SLURRIES IN A SLUDGE TANK

Energy Technology Data Exchange (ETDEWEB)

Poirier, M.; Qureshi, Z.; Restivo, M.; Steeper, T.; Williams, M.; Herman, D.

2011-08-02

The Small Column Ion Exchange (SCIX) process is being developed to remove cesium, strontium, and actinides from Savannah River Site (SRS) Liquid Waste using an existing waste tank (i.e., Tank 41H) to house the process. Following strontium, actinide, and cesium removal, the concentrated solids will be transported to a sludge tank (i.e., monosodium titanate (MST)/sludge solids to Tank 42H or Tank 51H and crystalline silicotitanate (CST) to Tank 40H) for eventual transfer to the Defense Waste Processing Facility (DWPF). Savannah River National Laboratory (SRNL) is conducting pilot-scale mixing tests to determine the pump requirements for mixing MST, CST, and simulated sludge. The purpose of this pilot scale testing is to determine the pump requirements for mixing MST and CST with sludge in a sludge tank and to determine whether segregation of particles occurs during settling. Tank 40H and Tank 51H have four Quad Volute pumps; Tank 42H has four standard pumps. The pilot-scale tank is a 1/10.85 linear scaled model of Tank 40H. The tank diameter, tank liquid level, pump nozzle diameter, pump elevation, and cooling coil diameter are all 1/10.85 of their dimensions in Tank 40H. The pump locations correspond to the current locations in Tank 40H (Risers B2, H, B6, and G). The pumps are pilot-scale Quad Volute pumps. Additional settling tests were conducted in a 30 foot tall, 4 inch inner diameter clear column to investigate segregation of MST, CST, and simulated sludge particles during settling.

Improvement of anaerobic digestion of sludge

Energy Technology Data Exchange (ETDEWEB)

Dohanyos, Michael; Zabranska, Jana; Kutil, Josef; Jenicek, Pavel

2003-07-01

Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of process conditions is frequently used pretreatment of input sludge and increase of process temperature. Thermophilic process brings a higher solids reduction and biogas production, the high resistance to foaming, no problems with odour, the higher effect of destroying pathogens and the improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in lysate centrifuge was proved in full-scale conditions causing increase of biogas production. The rapid thermal conditioning of digested sludge is acceptable method of particulate matter disintegration and solubilization. (author)

The influence of protruding filamentous bacteria on floc stability and solid-liquid separation in the activated sludge process.

Science.gov (United States)

Burger, Wilhelm; Krysiak-Baltyn, Konrad; Scales, Peter J; Martin, Gregory J O; Stickland, Anthony D; Gras, Sally L

2017-10-15

Filamentous bacteria can impact on the physical properties of flocs in the activated sludge process assisting solid-liquid separation or inducing problems when bacteria are overabundant. While filamentous bacteria within the flocs are understood to increase floc tensile strength, the relationship between protruding external filaments, dewatering characteristics and floc stability is unclear. Here, a quantitative methodology was applied to determine the abundance of filamentous bacteria in activated sludge samples from four wastewater treatment plants. An automated image analysis procedure was applied to identify filaments and flocs and calculate the length of the protruding filamentous bacteria (PFB) relative to the floc size. The correlation between PFB and floc behavior was then assessed. Increased filament abundance was found to increase interphase drag on the settling flocs, as quantified by the hindered settling function. Additionally, increased filament abundance was correlated with a lower gel point concentration leading to poorer sludge compactability. The floc strength factor, defined as the relative change in floc size upon shearing, correlated positively with filament abundance. This influence of external protruding filamentous bacteria on floc stability is consistent with the filamentous backbone theory, where filamentous bacteria within flocs increase floc resistance to shear-induced breakup. A qualitative correlation was also observed between protruding and internal filamentous structure. This study confirms that filamentous bacteria are necessary to enhance floc stability but if excessively abundant will adversely affect solid-liquid separation. The tools developed here will allow quantitative analysis of filament abundance, which is an improvement on current qualitative methods and the improved method could be used to assist and optimize the operation of waste water treatment plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of hazardous constituents in HLW supernate and implications for solid LLW generation

International Nuclear Information System (INIS)

Georgeton, G.K.

1994-01-01

High Level Waste supernates are hazardous due to the presence of small quantities of mercury, chromium, lead, silver and barium. The fate of these components based on process knowledge was evaluated. The supernates were grouped into Traditional (normal storage and evaporation), Dilute (stored in Type IV tanks), and Sludge Processing categories, and a review of the limited quantity of available sample data for each type of supernate was performed. The maximum concentration of each hazardous constituent was determined. The most restrictive hazardous constituent in Traditional and Sludge Processing supernates was determined to be mercury, and the most restrictive component in Dilute supernate was chromium. Containers of solid waste contaminated with these supernates must be manifested as nonhazardous before disposal as Low Level Waste in the engineered vaults in the EAV. A method was developed to screen waste containers in order to identify those containers that are nonhazardous. A criterion for 137 Cs content was arbitrarily set to 0.1 Ci, and the volume of supernate required to deposit 0.1 Ci was calculated. Containers with less than 0.1 Ci of 137 Cs and over 85 lb of solid waste contaminated with supernate from normal storage and evaporation operations are nonhazardous. Containers with less than 0.1 Ci of 137 Cs and over 170 lb of solid waste contaminated with supernate from sludge processing operations are nonhazardous. All containers of waste contaminated with supernate from Type IV tanks were evaluated as being nonhazardous. The screening method is readily applicable in the field - if the 137 Cs content of a container is below 0.1 Ci and the weight of the waste is greater than 85 or 170 lb (depending on waste type), the waste container is nonhazardous. Containers not satisfying both criteria will be segregated for additional evaluation

Energy recovery from wastewater treatment plants through sludge anaerobic digestion: effect of low-organic-content sludge.

Science.gov (United States)

Zhang, Yuyao; Li, Huan

2017-09-18

During anaerobic digestion, low-organic-content sludge sometimes is used as feedstock, resulting in deteriorated digestion performance. The operational experience of conventional anaerobic digestion cannot be applied to this situation. To investigate the feature of low-organic-content sludge digestion and explain its intrinsic mechanism, batch experiments were conducted using designed feedstock having volatile solids (VS) contents that were 30-64% of total solids (TS). The results showed that the accumulative biogas yield declined proportionally from 173.7 to 64.8 ml/g VS added and organic removal rate decreased from 34.8 to 11.8% with decreasing VS/TS in the substrate. The oligotrophic environment resulting from low-organic-content substrates led to decreased microbial activity and a switch from butyric fermentation to propionic fermentation. A first-order model described the biogas production from the batch experiments very well, and the degradation coefficient decreased from 0.159 to 0.069 day -1 , exhibiting a positive relation with organic content in substrate. The results observed here corroborated with data from published literature on anaerobic digestion of low-organic-content sludge and showed that it may not be feasible to recover energy from sludge with an organic content lower than 50% through mono digestion.

Types and treatment of sewage sludges: Practice in the Federal Republic of Germany

International Nuclear Information System (INIS)

Tabasaran, M.O.

1975-01-01

The sludge that is formed by the various processes in the sewage treatment plant consists mainly of water with a small amount of organic and inorganic suspended solids. It contains pathogenic agents and biological inhibitors, and must be prepared and brought into a form where it is less dangerous to the environment. The de-watering of the sludge is the first step in sludge handling. The solids content of the raw sludge, which is usually between 5 and 10%, can be increased by gravity thickening to 15%, by centrifuging or straining-band-pressing up to 30%, and by pressure-filtration up to 40%. The process of drying enables a substance with almost no moisture to be obtained. Generally the sludge will be either mixed before de-watering with coagulation agencies, or preheated, or its colloidal components biochemically oxidized in order to accelerate the withdrawal of the water. One of the most common methods of disposal is the transport of sludge to a land filling, usually together with the solid refuse of the community. For this purpose the moisture content of the sludge should not be more than 60 to 70 percent. The disposal of sludge into the sea can be practised in coastal towns, but the ecological effects of this kind of sludge removal are still disputed. More expedient is the agricultural utilization of sludge, particularly if the sludge is composted together with a carbon carrier such as city refuse which would make it a very suitable soil improver. In the Federal Republic of Germany the wet oxidation of sludge is applied in a few cases. The most common process is anaerobic alkaline digestion. The incineration of sludge is more economical than drying, but still too, expensive in comparison with other approved processes. (author)

Extracellular Polymers in Granular Sludge from Different Upflow Anaerobic Sludge Blanket (UASB) Reactors

DEFF Research Database (Denmark)

Schmidt, Jens Ejbye; Ahring, Birgitte Kiær

1994-01-01

lysis. ECP contents of 41 to 92 mg · g−1 volatile suspended solids of granules were found depending on the type of granular sludge examined. The content of polysaccharides, protein and lipids in the extracted ECP was quantified. Furthermore, the different methyl esters of the lipids were determined...... of an upflow anaerobic sludge blanket reactor from a sugar-containing waste-water to a synthetic waste-water containing acetate, propionate and butyrate resulted in a decrease in both the protein and polysaccharide content and an increase in the lipid content of the extracellular material. Furthermore...

Ferrocyanide Safety Program: Waste tank sludge rheology within a hot spot or during draining

International Nuclear Information System (INIS)

Fauske, H.K.; Cash, R.J.

1993-11-01

The conditions under which ferrocyanide waste sludge flows as a homogeneous non-Newtonian two-phase (solid precipitate-liquid) mixture rather than as a liquid through a porous medium (of stationary precipitate) are examined theoretically, based on the notion that the preferred rheological behavior of the sludge is the one which imposes the least resistance to the sludge flow. The homogeneous two-phase mixture is modeled as a power-law fluid and simple criteria are derived that show that the homogeneous power-law sludge-flow is a much more likely flow situation than the porous medium model of sludge flow. The implication of this finding is that the formation of a hot spot or the drainage of sludge from a waste tank are not likely to result in the uncovering (drying) and subsequent potential overheating of the reactive-solid component of the sludge

Bioleaching of heavy metals from sewage sludge using Acidithiobacillus thiooxidans

Science.gov (United States)

Wen, Ye-Ming; Lin, Hong-Yan; Wang, Qing-Ping; Chen, Zu-Liang

2010-11-01

Acidithiobacillus thiooxidans was isolated from sewage sludge using the incubation in the Waksman liquor medium and the inoculation in Waksman solid plate. It was found that the optimum conditions of the bioleaching included solid concentration 2%, sulfur concentration 5 gṡL-1 and cell concentration 10%. The removal efficiency of Cr, Cu, Pb and Zh in sewage sludge, which was obtained from waste treatment plant, Jinshan, Fuzhou, was 43.65%, 96.24%, 41.61% and 96.50% in the period of 4˜10 days under the optimum conditions, respectively. After processing using the proposed techniques, the heavy metals in sewage sludge did meet the requirement the standards of nation.

Hydrogen and syngas production from sewage sludge via steam gasification

Energy Technology Data Exchange (ETDEWEB)

Nipattummakul, Nimit [The Combustion Laboratory, Dept. of Mechanical Engineering, University of Maryland, College Park, MD (United States); The Waste Incineration Research Center, Dept. of Mechanical and Aerospace Engineering, King Mongkut' s University of Technology, North Bangkok (Thailand); Ahmed, Islam I.; Gupta, Ashwani K. [The Combustion Laboratory, Dept. of Mechanical Engineering, University of Maryland, College Park, MD (United States); Kerdsuwan, Somrat [The Waste Incineration Research Center, Dept. of Mechanical and Aerospace Engineering, King Mongkut' s University of Technology, North Bangkok (Thailand)

2010-11-15

High temperature steam gasification is an attractive alternative technology which can allow one to obtain high percentage of hydrogen in the syngas from low-grade fuels. Gasification is considered a clean technology for energy conversion without environmental impact using biomass and solid wastes as feedstock. Sewage sludge is considered a renewable fuel because it is sustainable and has good potential for energy recovery. In this investigation, sewage sludge samples were gasified at various temperatures to determine the evolutionary behavior of syngas characteristics and other properties of the syngas produced. The syngas characteristics were evaluated in terms of syngas yield, hydrogen production, syngas chemical analysis, and efficiency of energy conversion. In addition to gasification experiments, pyrolysis experiments were conducted for evaluating the performance of gasification over pyrolysis. The increase in reactor temperature resulted in increased generation of hydrogen. Hydrogen yield at 1000 C was found to be 0.076 g{sub gas} g{sub sample}{sup -1}. Steam as the gasifying agent increased the hydrogen yield three times as compared to air gasification. Sewage sludge gasification results were compared with other samples, such as, paper, food wastes and plastics. The time duration for sewage sludge gasification was longer as compared to other samples. On the other hand sewage sludge yielded more hydrogen than that from paper and food wastes. (author)

New sorbent in the dispersive solid phase extraction step of quick, easy, cheap, effective, rugged, and safe for the extraction of organic contaminants in drinking water treatment sludge.

Science.gov (United States)

Cerqueira, Maristela B R; Caldas, Sergiane S; Primel, Ednei G

2014-04-04

Recent studies have shown a decrease in the concentration of pesticides, pharmaceuticals and personal care products (PCPs) in water after treatment. A possible explanation for this phenomenon is that these compounds may adhere to the sludge; however, investigation of these compounds in drinking water treatment sludge has been scarce. The sludge generated by drinking water treatment plants during flocculation and decantation steps should get some special attention not only because it has been classified as non-inert waste but also because it is a very complex matrix, consisting essentially of inorganic (sand, argil and silt) and organic (humic substances) compounds. In the first step of this study, three QuEChERS methods were used, and then compared, for the extraction of pesticides (atrazine, simazine, clomazone and tebuconazole), pharmaceuticals (amitriptyline, caffeine, diclofenac and ibuprofen) and PCPs (methylparaben, propylparaben, triclocarban and bisphenol A) from drinking water treatment sludge. Afterwards, the study of different sorbents in the dispersive solid phase extraction (d-SPE) step was evaluated. Finally, a new QuEChERS method employing chitin, obtained from shrimp shell waste, was performed in the d-SPE step. After having been optimized, the method showed limits of quantification (LOQ) between 1 and 50 μg kg(-1) and the analytical curves showed r values higher than 0.98, when liquid chromatography tandem mass spectrometry was employed. Recoveries ranged between 50 and 120% with RSD≤15%. The matrix effect was evaluated and compensated with matrix-matched calibration. The method was applied to drinking water treatment sludge samples and methylparaben and tebuconazole were found in concentration

Cleaning IBL secondary sludge in the tubular plate steam generators

International Nuclear Information System (INIS)

Montoro de Frutos, E.; Gonzalez Carballo, S.

2012-01-01

After cleanings Sludge Lancing using 250bar made from the center lane, identifies an area of solidified remaining sludge on the tube plate. Since late 2010, IBERDROLA-SAVAC has developed Inner System Bundle Lancing (IBL), which locally involves shooting a jet of water at high pressure 590bar directly impacting sludge areas within the tube bundle hard to detach and break into small pieces that can be extracted from GV through a closed circuit suction.

Environmental & economic life cycle assessment of current & future sewage sludge to energy technologies.

Science.gov (United States)

Mills, N; Pearce, P; Farrow, J; Thorpe, R B; Kirkby, N F

2014-01-01

The UK Water Industry currently generates approximately 800GWh pa of electrical energy from sewage sludge. Traditionally energy recovery from sewage sludge features Anaerobic Digestion (AD) with biogas utilisation in combined heat and power (CHP) systems. However, the industry is evolving and a number of developments that extract more energy from sludge are either being implemented or are nearing full scale demonstration. This study compared five technology configurations: 1 - conventional AD with CHP, 2 - Thermal Hydrolysis Process (THP) AD with CHP, 3 - THP AD with bio-methane grid injection, 4 - THP AD with CHP followed by drying of digested sludge for solid fuel production, 5 - THP AD followed by drying, pyrolysis of the digested sludge and use of the both the biogas and the pyrolysis gas in a CHP. The economic and environmental Life Cycle Assessment (LCA) found that both the post AD drying options performed well but the option used to create a solid fuel to displace coal (configuration 4) was the most sustainable solution economically and environmentally, closely followed by the pyrolysis configuration (5). Application of THP improves the financial and environmental performance compared with conventional AD. Producing bio-methane for grid injection (configuration 3) is attractive financially but has the worst environmental impact of all the scenarios, suggesting that the current UK financial incentive policy for bio-methane is not driving best environmental practice. It is clear that new and improving processes and technologies are enabling significant opportunities for further energy recovery from sludge; LCA provides tools for determining the best overall options for particular situations and allows innovation resources and investment to be focused accordingly. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effects of Metal Nanoparticles on Methane Production from Waste-Activated Sludge and Microorganism Community Shift in Anaerobic Granular Sludge

Science.gov (United States)

Wang, Tao; Zhang, Dong; Dai, Lingling; Chen, Yinguang; Dai, Xiaohu

2016-05-01

Extensive use of nanoparticles (NPs) in consumer and industrial products has led to concerns about their potential environmental impacts; however, the influences of different NPs (e.g., nZVI (nano zero-valent iron), Ag NPs, Fe2O3 NPs and MgO NPs) on the anaerobic digestion of sludge have not yet been studied in depth. Additionally, a new guideline or the use of different NPs in the anaerobic digestion of sludge should be established to improve the anaerobic digestion of sludge and avoid inhibitory effects. This study investigated the effects of four representative NPs (i.e., nZVI, Ag NPs, Fe2O3 NPs and MgO NPs) on methane production during the anaerobic digestion of waste activated sludge (WAS). The presence of 10 mg/g total suspended solids (TSS) nZVI and 100 mg/g TSS Fe2O3 NPs increased methane production to 120% and 117% of the control, respectively, whereas 500 mg/g TSS Ag NPs and 500 mg/g TSS MgO NPs generated lower levels of methane production (73.52% and 1.08% that of the control, respectively). These results showed that low concentrations of nZVI and Fe2O3 NPs promoted the amount of microbes (Bacteria and Archaea) and activities of key enzymes but that higher concentrations of Ag NPs and MgO NPs inhibited them.

Enzyme treatment to decrease solids and improve digestion of ...

African Journals Online (AJOL)

The aim of anaerobic digestion of primary sewage sludge is to convert the carbonaceous material contained in the solids into methane and carbon dioxide. The products of digestion are therefore gases, stabilised sludge solids which are subsequently dewatered and disposed of, and sludge liquor which is generally further ...

Treatment and disposal of refinery sludges: Indian scenario.

Science.gov (United States)

Bhattacharyya, J K; Shekdar, A V

2003-06-01

Crude oil is a major source of energy and feedstock for petrochemicals. Oily sludge, bio-sludge and chemical sludge are the major sludges generated from the processes and effluent treatment plants of the refineries engaged in crude oil refining operations. Refineries in India generate about 28,220 tons of sludge per annum. Various types of pollutants like phenols, heavy metals, etc. are present in the sludges and they are treated as hazardous waste. Oily sludge, which is generated in much higher amount compared to other sludges, contains phenol (90-100 mg/kg), nickel (17-25 mg/kg), chromium (27-80 mg/kg), zinc (7-80 mg/kg), manganese (19-24 mg/kg), cadmium (0.8-2 mg/kg), copper (32-120 mg/kg) and lead (0.001-0.12 mg/ kg). Uncontrolled disposal practices of sludges in India cause degradation of environmental and depreciation of aesthetic quality. Environmental impact due to improper sludge management has also been identified. Salient features of various treatment and disposal practices have been discussed. Findings of a case study undertaken by the authors for Numaligarh Refinery in India have been presented. Various system alternatives have been identified for waste management in Numaligarh Refinery. A ranking exercise has been carried out to evaluate the alternatives and select the appropriate one. A detailed design of the selected waste management system has been presented.

Influences of extracellular polymeric substances on the dewaterability of sewage sludge during bioleaching.

Science.gov (United States)

Zhou, Jun; Zheng, Guanyu; Zhang, Xueying; Zhou, Lixiang

2014-01-01

Extracellular polymeric substances (EPS) play important roles in regulating the dewaterability of sludge. This study sought to elucidate the influence of EPS on the dewaterability of sludge during bioleaching process. Results showed that, in bioleaching system with the co-inoculation of Acidithiobacillus thiooxidans TS6 and Acidithiobacillus ferrooxidans LX5 (A. t+A. f system), the capillary suction time (CST) of sludge reduced from 255.9 s to 25.45 s within 48 h, which was obviously better than the controls. The correlation analysis between sludge CST and sludge EPS revealed that the sludge EPS significantly impacted the dewaterability of sludge. Sludge CST had correlation with protein content in slime and both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers, and the decrease of protein content in slime and decreases of both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers improved sludge dewaterability during sludge bioleaching process. Moreover, the low sludge pH (2.92) and the increasing distribution of Fe in the solid phase were another two factors responsible for the improvement of sludge dewaterability during bioleaching. This study suggested that during sludge bioleaching the growth of Acidithiobacillus species resulted in the decrease of sludge pH, the increasing distribution of Fe in the solid phase, and the decrease of EPS content (mainly including protein and/or polysaccharide) in the slime, TB-EPS, and Slime+LB+TB layers, all of which are helpful for sludge dewaterability enhancement.

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.

Construction materials as a waste management solution for cellulose sludge

International Nuclear Information System (INIS)

Modolo, R.; Ferreira, V.M.; Machado, L.M.; Rodrigues, M.; Coelho, I.

2011-01-01

Sustainable waste management system for effluents treatment sludge has been a pressing issue for pulp and paper sector. Recycling is always recommended in terms of environmental sustainability. Following an approach of waste valorisation, this work aims to demonstrate the technical viability of producing fiber-cement roof sheets incorporating cellulose primary sludge generated on paper and pulp mills. From the results obtained with preliminary studies it was possible to verify the possibility of producing fiber-cement sheets by replacing 25% of the conventional used virgin long fiber by primary effluent treatment cellulose sludge. This amount of incorporation was tested on an industrial scale. Environmental parameters related to water and waste, as well as tests for checking the quality of the final product was performed. These control parameters involved total solids in suspension, dissolved salts, chlorides, sulphates, COD, metals content. In the product, parameters like moisture, density and strength were controlled. The results showed that it is possible to replace the virgin long fibers pulp by primary sludge without impacts in final product characteristics and on the environment. This work ensures the elimination of significant waste amounts, which are nowadays sent to landfill, as well as reduces costs associated with the standard raw materials use in the fiber-cement industrial sector.

A summary of recent developments in the sludge irradiation program at Sandia laboratories

International Nuclear Information System (INIS)

Morris, M.E.; Sivinski, J.S.; Brandon, J.R.; Neuhauser, K.S.; Ward, R.L.

1978-01-01

Sandia Laboratories has shifted the emphasis of its Sewage Sludge Irradiation Program toward treating dried sewage sludges rather than liquid sludges for the following reasons: (1) cities' interests in composting sewage sludge before final disposal; (2) need for disinfection of the product before sale to the public; and (3) low cost of disinfection by radiation processing. As a result of this shift, the Sandia Irradiator for Dried Sewage Solids (SIDSS), was designed and is near completion. The irradiator will treat up to 8 tons/day of solids with a 1 megarad absorbed dose. A bucket conveyor will transport the sewage sludge past a 1 megacurie cesium-137 γ-ray source. If a lower dose than 1 megarad is acceptable for disinfection, the daily throughput of the irradiator will be correspondingly increased. The irradiator is designed so that the cesium-137 γ-ray sources used to charge the facility can be manipulated underwater. After source unloading is complete, the water will be drained and the irradiator will be operated dry. Either bagged or bulk solids can be irradiated with the system. (Auth.)

Characterization and leaching study of sludge from Melton Valley Storage Tank W-25

International Nuclear Information System (INIS)

Collins, J.L.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Anderson, K.K.

1997-08-01

One of the greatest challenges facing the Department of Energy (DOE) is the remediation of the 100 million gallons of high-level and low-level radioactive waste in the underground storage tanks at its Hanford, Savannah River, Oak Ridge, Idaho, and Fernald sites. Bench-scale batch tests have been conducted with sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation processes for use in a comprehensive sludge-processing flow sheet for concentrating the radionuclides and reducing the volumes of storage tanks wastes for final disposal. This report discusses the hot cell apparatus, the characterization of the sludge, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge. Approximately 5 L of sludge/supernate from MVST W-25 was retrieved and transferred to a stainless steel tank for mixing and storage in a hot cell. Samples were centrifuged to separate the sludge liquid and the sludge solids. Air-dried samples of sludge were analyzed to determine the concentrations of radionuclides, other metals, and anions. Based upon the air-dried weight, about 41% of the centrifuged, wet sludge solids was water. The major alpha-, gamma-, and beta-emitting radionuclides in the centrifuged, wet sludge solids were 137 Cs, 60 Co, 154 Eu, 241 Am, 244 Cm, 90 Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and the anions were Na, Ca, Al, K, Mg, NO 3 - , CO 3 2- , OH - , and O 2- . The organic carbon content was 3.0 ± 1.0%. The pH was 13

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

Assessment of biogas production in Argentina from co-digestion of sludge and municipal solid waste.

Science.gov (United States)

Morero, Betzabet; Vicentin, Rocio; Campanella, Enrique A

2017-03-01

In Argentina, there is an important potential to utilize organic waste to generate bioenergy. This work analyzes the environmental impacts and the energetic and economic requirements of the biogas produced by digesting the sewage sludge (SS) produced in a wastewater treatment plant in a medium city in Argentina. The SS is co-digested with the organic fraction of municipal solid waste (OFMSW), and the basis of this study is the life cycle assessment (LCA). The LCA is performed according to ISO 14040-44 using the SimaPro simulator. First, the transport of the raw materials to the biogas plant was defined. Then, the co-digestion and the biogas treatment for final use were evaluated. The co-digestion was improved with glycerol, and the generation of biogas was estimated using the GPS-X software. Two alternatives for the end use of biogas were considered: combined heat and power (CHP) and biomethane generation. For the first, H 2 S and water vapor were removed from the raw biogas stream, and for the second, also CO 2 was removed. The H 2 S removal process was simulated in the SuperPro software by anaerobic biofiltration. The same software was used to simulate the removal of CO 2 absorption-desorption with water as solvent. Finally, the environmental impacts related to the end use of biogas (CHP and biomethane) were evaluated. The environmental, energetic and economic analyses showed that the co-digestion of SS and OFMSW has great potential for reducing the environmental impacts and increasing the economic and energetic value of the substances via the production of biomethane, electricity and, potentially, fertilizer. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

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.

Rheological characterisation of municipal sludge: a review.

Science.gov (United States)

Eshtiaghi, Nicky; Markis, Flora; Yap, Shao Dong; Baudez, Jean-Christophe; Slatter, Paul

2013-10-01

Sustainable sludge management is becoming a major issue for wastewater treatment plants due to increasing urban populations and tightening environmental regulations for conventional sludge disposal methods. To address this problem, a good understanding of sludge behaviour is vital to improve and optimize the current state of wastewater treatment operations. This paper provides a review of the recent experimental works in order for researchers to be able to develop a reliable characterization technique for measuring the important properties of sludge such as viscosity, yield stress, thixotropy, and viscoelasticity and to better understand the impact of solids concentrations, temperature, and water content on these properties. In this context, choosing the appropriate rheological model and rheometer is also important. Copyright © 2013 Elsevier Ltd. All rights reserved.

Gravity settling of Hanford single-shell tank sludges

International Nuclear Information System (INIS)

Brooks, K.P.; Rector, D.R.; Smith, P.A.

1999-01-01

The US Department of Energy plans to use gravity settling in million-gallon storage tanks while pretreating sludge on the Hanford site. To be considered viable in these large tanks, the supernatant must become clear, and the sludge must be concentrated in an acceptable time. These separations must occur over the wide range of conditions associated with sludge pretreatment. In the work reported here, gravity settling was studied with liter quantities of actual single-shell tank sludge from hanford Tank 241-C-107. Because of limited sludge availability, an approach was developed using the results of these liter-scale tests to predict full-scale operation. Samples were centrifuged at various g-forces to simulate compaction with higher layers of sludge. A semi-empirical settling model was then developed incorporating both the liter-scale settling data and the centrifuge compression results to describe the sludge behavior in a million-gallon tank. The settling model predicted that the compacted sludge solids would exceed 20 wt% in less than 30 days of settling in a 10-m-tall tank for all pretreatment steps

Physicochemical and thermal characteristics of the sludge produced after thermochemical treatment of petrochemical wastewater.

Science.gov (United States)

Verma, Shilpi; Prasad, Basheshwar; Mishra, I M

2012-01-01

The present work describes the physicochemical and thermal characteristics of the sludge generated after thermochemical treatment of wastewater from a petrochemical plant manufacturing purified terephthalic acid (PTA). Although FeCl3 was found to be more effective than CuSO4 in removing COD from wastewater, the settling and filtration characteristics of FeCl3 sludge were poorer. Addition of cationic polyacrylamide (CPAA; 0.050kg/m3) to the FeCl3 wastewater system greatly improved the values of the filter characteristics of specific cake resistance (1.2 x 10(8) m/kg) and resistance of filter medium (9.9 x 10(8) m(-1)) from the earlier values of 1.9 x 10(9) m/kg and 1.7 x 10(8) m(-1), respectively. SEM-EDAX and FTIR studies were undertaken, to understand the sludge structure and composition, respectively. The moisture distribution in the CuSO4 sludge, FeCl3 sludge and FeCl3 + CPAA sludge showed that the amount of bound water content in the CuSO4 and FeCl3 + CPAA sludges is less than that of the FeCl3 sludge and there was a significant reduction in the solid-water bond strength of FeCl3 + CPAA sludge, which was responsible for better settling and filtration characteristics. Due to the hazardous nature of the sludge, land application is not a possible route of disposal. The thermal degradation behaviour of the sludge was studied for its possible use as a co-fuel. The studies showed that degradation behaviour of the sludge was exothermic in nature. Because of the exothermic nature of the sludge, it can be used in making fuel briquettes or it can be disposed of via wet air oxidation.

Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin

International Nuclear Information System (INIS)

Lee, I.H.; Kuan, Y.-C.; Chern, J.-M.

2006-01-01

Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 deg. C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results

Material balance of two sewage sludge incineration systems; Methods and results - disposal of solid residues. Stoffflussanalyse bei zwei Klaerschlammverbrennungsanlagen; Methodik und Ergebnisse - Entsorgung der festen Rueckstaende

Energy Technology Data Exchange (ETDEWEB)

Staeubli, B. (Abt. Abfallwirtschaft des Amtes fuer Gewaesserschutz und Wasserbau des Kantons Zuerich (Switzerland)); Keller, C. (Elektrowatt Ingenieurunternehmung AG, Zurich (Switzerland))

1993-02-01

Material balances were analyzed in two Swiss sewage sludge combustion plants. The methodology is described. Aspects of the standards set for waste management in Switzerland are described. The two incinerations are described. The volumes and compositions of the sewage sludges and all gaseous, liquid, and solid products are gone into. The possibilities of recycling and dumping of combustion products are reviewed in consideration of the volumes and compositions of combustion products. The text is supplemented by tables and flowsheets. (orig.)

Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community

Science.gov (United States)

Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

2016-02-01

Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology.

Rheology of Savannah River site tank 42 HLW radioactive sludge

International Nuclear Information System (INIS)

Ha, B.C.

1997-01-01

Knowledge of the rheology of the radioactive sludge slurries at the Savannah River Site is necessary in order to ensure that they can be retrieved from waste tanks and processed for final disposal. At Savannah River Site, Tank 42 sludge represents on of the first HLW radioactive sludges to be vitrified in the Defense Waste Processing Facility. The rheological properties of unwashed Tank 42 sludge slurries at various solids concentrations were measured remotely in the Shielded Cells at the Savannah River Technology Center using a modified Haake Rotovisco viscometer

Characterization of sludges of La Golondrina WWTP: sludges as final containers of the domestic wastewater pollution; Caracterizacion de fangos de la EDAR La Golondrina (EMACSA-Cordoba): su funcion como receptores finales de la contaminacion del agua residual urbana

Energy Technology Data Exchange (ETDEWEB)

Marin Galvin, R.; Alonso Perez de siles, L.; Rojas Moreno, F. J.

2005-07-01

Treatment of wastewater is to concentrate the original pollution in a by-product: the wastewater sludge or bio-solid. As example, La Golondrina WWTP (Cordoba-spain) promotes the production of 1,3 kg of sludge per m''3 of wastewater, yielding logically a treated water according to laws. Furthermore, the treatment process there applied reduces the levels of nine majority metals (Cu, Fe, Mn, Pb, Cd, Ni, Cr, Zn, Hg) from 2,72 mg/l to 1.42 mg/l in the treated water, generating almost, a sludge agrees with the spanish normative to sludge intended to agricultural use (its main fate). Summarizing, the treatment of wastewater supposes the concentration of the original biodegradable load into the sludge around 340 times, while metals exhibited a different concentration degree for each one (from 10.000 times for Fe, u pto 1-2 times for Cd and Hg). Finally, the concentration degree of a metal in the sludge is mainly led by the removed concentration of metal in the treatment process, and after, by the original concentration of metal in the influent wastewater. (Author) 24 refs.

The influence of the anaerobic digestion process on the sewage sludges rheological behaviour

Energy Technology Data Exchange (ETDEWEB)

Monteiro, P.S. [Porto Univ. (Portugal). Facultade de Engenharia. Inst. de Hidraulica e Recursos Hidricos

1998-12-31

During the anaerobic digestion process, a significant part of the organic matter is sewage sludge is decomposed to form other organic and inorganic compounds in dissolved form. The biological transformation of a substantial part of the organic solids has, certainly, a strong influence on the rheological characteristics of the sludges. In this paper a test facility was set up to simulate sewage sludge digestion and periodic observations on the evolution of the sludge characteristics were carried out. Results of this study show that important changes on the sludge rheological behaviour occur during anaerobic digestion and that the evolution of those changes is related with the degree of digestion. Moreover, it is shown that the verified high degree of physical changes can not be demonstrated only by the total solids concentration variation and two hypothesis are proposed to explain those changes.

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.

Rising Sludge in Secondary Settlers Due to Denitrification

DEFF Research Database (Denmark)

Henze, Mogens; Dupont, Rene; Grau, Peter

1993-01-01

High suspended solids concentrations in settler effluents can be caused by rising sludge, which is the effect of flotation of solids by nitrogen gas resulting from biological denitrification. Many factors influence the nitrogen gas bubble evolution. The most important factor is the rate...

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.

Disintegration impact on sludge digestion process.

Science.gov (United States)

Dauknys, Regimantas; Rimeika, Mindaugas; Jankeliūnaitė, Eglė; Mažeikienė, Aušra

2016-11-01

The anaerobic sludge digestion is a widely used method for sludge stabilization in wastewater treatment plant. This process can be improved by applying the sludge disintegration methods. As the sludge disintegration is not investigated enough, an analysis of how the application of thermal hydrolysis affects the sludge digestion process based on full-scale data was conducted. The results showed that the maximum volatile suspended solids (VSS) destruction reached the value of 65% independently on the application of thermal hydrolysis. The average VSS destruction increased by 14% when thermal hydrolysis was applied. In order to have the maximum VSS reduction and biogas production, it is recommended to keep the maximum defined VSS loading of 5.7 kg VSS/m(3)/d when the thermal hydrolysis is applied and to keep the VSS loading between 2.1-2.4 kg VSS/m(3)/d when the disintegration of sludge is not applied. The application of thermal hydrolysis leads to an approximately 2.5 times higher VSS loading maintenance comparing VSS loading without the disintegration; therefore, digesters with 1.8 times smaller volume is required.

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)

Characterization and leaching study of sludge from Melton Valley Storage Tank W-25

Energy Technology Data Exchange (ETDEWEB)

Collins, J.L.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Anderson, K.K.

1997-08-01

One of the greatest challenges facing the Department of Energy (DOE) is the remediation of the 100 million gallons of high-level and low-level radioactive waste in the underground storage tanks at its Hanford, Savannah River, Oak Ridge, Idaho, and Fernald sites. Bench-scale batch tests have been conducted with sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation processes for use in a comprehensive sludge-processing flow sheet for concentrating the radionuclides and reducing the volumes of storage tanks wastes for final disposal. This report discusses the hot cell apparatus, the characterization of the sludge, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge. Approximately 5 L of sludge/supernate from MVST W-25 was retrieved and transferred to a stainless steel tank for mixing and storage in a hot cell. Samples were centrifuged to separate the sludge liquid and the sludge solids. Air-dried samples of sludge were analyzed to determine the concentrations of radionuclides, other metals, and anions. Based upon the air-dried weight, about 41% of the centrifuged, wet sludge solids was water. The major alpha-, gamma-, and beta-emitting radionuclides in the centrifuged, wet sludge solids were {sup 137}Cs, {sup 60}Co, {sup 154}Eu, {sup 241}Am, {sup 244}Cm, {sup 90}Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and the anions were Na, Ca, Al, K, Mg, NO{sub 3}{sup {minus}}, CO{sub 3}{sup 2{minus}}, OH{sup {minus}}, and O{sub 2{minus}}. The organic carbon content was 3.0 {+-} 1.0%. The pH was 13.

Rapid thermal conditioning of sewage sludge

Science.gov (United States)

Zheng, Jianhong

Rapid thermal conditioning (RTC) is a developing technology recently applied to sewage sludge treatment. Sludge is heated rapidly to a reaction temperature (up to about 220sp°C) under sufficient pressure to maintain the liquid phase. Reaction is quenched after 10 to 30 seconds when the mixture of sludge and steam pass through a pressure let-down valve. This process reduces the amount of sludge requiring land disposal, eliminates the need for polymer coagulant, improves dewaterability, increases methane production, and further reduces the concentration of pathogens. The odor problem associated with traditional thermal conditioning processes is largely minimized. Ammonia removal is readily integrated with the process. For this research, a pilot unit was constructed capable of processing 90 liters of sludge per hour. Over 22 runs were made with this unit using sludge from New York City Water Pollution Control Plants (WPCP). Sludges processed in this equipment were tested to determine the effect of RTC operating conditions on sludge dewaterability, biodegradability, and other factors affecting the incorporation of RTC into wastewater treatment plants. Dewaterability of thermally conditioned sludge was assessed for cetrifugeability and filterability. Bench scale centrifugation was used for evaluating centrifugeability, pressure filtration and capillary suction time (CST) for filterability. A mathematical model developed for centrifuge dewatering was used to predict the effect of RTC on full scale centrifuge performance. Particle size distribution and solids density of raw and treated PDS were also analyzed. An observed increase in sludge solids density at least partially explains its improved centrifugeability. An investigation of thermally conditioned amino acids showed that the L-isomer is highly biodegradable while the D-isomers are generally less so. Glucose is highly biodegradable, but rapidly becomes refractory as thermal conditioning time is lengthened. This

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.

Characterization of tannery sludge from the leather industry of Franca industrial district, SP, Brazil; Caracterizacao de um lodo de cromo proveniente da industria de couro do distrito industrial de Franca

Energy Technology Data Exchange (ETDEWEB)

Chambi, M.M.; Toffoli, S.M., E-mail: marvinchp@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Departamento de Engenharia Metalurgica

2011-07-01

The industry of leather manufacture generates large quantities of solid leather waste with characteristics of high-polluting and hazardous conditions. Among these wastes, stands out the wet blue leather (chromed leather scraps), and the tanning sludge and secondary sludge generated in the processes of effluents treatment. These wastes contain Cr(III), which, under oxidizing conditions, can turn into Cr (VI), which is highly toxic. However, these wastes are a potential source of chromium oxide (traditional industrial pigment), which could be used by the glass and ceramic enamel industries. In this study, a preliminary characterization of a chromium sludge from the industrial district of Franca-SP was conducted. X-ray diffraction (XRD), chemical (XRF) and thermal (DTA / TG) analyses were used to determine the physical and chemical characteristics of this solid waste. The potential of using this material as an available and cheap pigment for the manufacture of enamels and glass is discussed. (author)

Assessment of microbial viability in municipal sludge following ultrasound and microwave pretreatments and resulting impacts on the efficiency of anaerobic sludge digestion.

Science.gov (United States)

Cella, Monica Angela; Akgul, Deniz; Eskicioglu, Cigdem

2016-03-01

A range of ultrasonication (US) and microwave irradiation (MW) sludge pretreatments were compared to determine the extent of cellular destruction in micro-organisms within secondary sludge and how this cellular destruction translated to anaerobic digestion (AD). Cellular lysis/inactivation was measured using two microbial viability assays, (1) Syto 16® Green and Sytox® Orange counter-assay to discern the integrity of cellular membranes and (2) a fluorescein diacetate assay to understand relative enzymatic activity. A range of MW intensities (2.17-6.48 kJ/g total solids or TS, coinciding temperatures of 60-160 °C) were selected for comparison via viability assays; a range of corresponding US intensities (2.37-27.71 kJ/g TS, coinciding sonication times of 10-60 min at different amplitudes) were also compared to this MW range. The MW pretreatment of thickened waste activated sludge (tWAS) caused fourfold to fivefold greater cell death than non-pretreated and US-pretreated tWAS. The greatest microbial destruction occurred at MW intensities greater than 2.62 kJ/g TS of sludge, after which increased energy input via MW did not appear to cause greater microbial death. In addition, the optimal MW pretreatment (80 °C, 2.62 kJ/g TS) and corresponding US pretreatment (10 min, 60 % amplitude, 2.37 kJ/g TS) were administered to the tWAS of a mixed sludge and fed to anaerobic digesters over sludge retention times (SRTs) of 20, 14, and 7 days to compare effects of feed pretreatment on AD efficiency. The digester utilizing MW-pretreated tWAS (80 °C, 2.62 kJ/g TS) had the greatest fecal coliform removal (73.4 and 69.8 % reduction, respectively), greatest solids removal (44.2 % TS reduction), and highest overall methane production (248.2 L CH4/kg volatile solids) at 14- and 7-day SRTs. However, despite the fourfold to fivefold increases in cell death upon pretreatment, improvements from the digester fed MW-pretreated sludge were marginal (i.e., increases in efficiency of less

The production of sludge in anaerobic purification treatments; Produccion de fangos en la depuracion anaerobica

Energy Technology Data Exchange (ETDEWEB)

Vazquez Borges, E. del R.; Mejia Sanchez, G.M. [Departamento de Ingenieria Ambiental, Facultad de Ingenieria, Universidad Autonoma de Yucatan (Mexico)

1996-04-01

One of the characteristics of anaerobic processes is the low level of sludge production. However it is important to maintain a certain concentration of biomass in the system to ensure sufficient removal of organic matter. As organic matter degrades, part of it is transformed into gas while the rest remains in the system as biomass, it is important to control the concentration of sludge in the system as a way of enchaincing process efficiency. The quality of sludge produced during the anaerobic digestion process is related to the amount of substrate consumed and the amount of gas generated and particularly to the concentration of volatile suspended solids (active biomass). nevertheless, the operating conditions of the digester can modify the distribution of the results of the bacterial metabolism. The present study examines the influence of hydraulic resistance time, organic, load and substrate concentration on sludge production and the relation between sludge production and the amount of substrate consumed by the system for each set of cinditions. The findings were obtained from a experiment in which a modified UASB digester was operated with a slow mixing system. (Author) 7 refs.

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

Estimation of restaurant solid waste generation rates

International Nuclear Information System (INIS)

Heck, H.H.; Major, I.

2002-01-01

Most solid waste utilities try to create a billing schedule that is proportional to solid waste generation rates. This research was trying to determine if the current billing rate structure was appropriate or if a different rate structure should be implemented. A multiple regression model with forward stepwise addition was developed which accurately predicts weekly solid waste generation rates for restaurants. The model was based on a study of daily solid waste generation at twenty-one different businesses. The weight and volume of solid waste generated was measure daily for two weeks during the winter and two weeks during the summer. Researchers followed the collection truck and measured the volume and weight of the container contents. Data was collected on the following independent variables describing each establishment; weight of waste per collection, volume per collection, container utilization factor, building area, contract haulers bill, yearly property tax, yearly solid waste tax, average number of collections per week, type of restaurant, modal number of collections per week, storage container size, waste density, number of employees, number of hours open per week, and weekly collection capacity (collections per week times storage container size). Independent variables were added to the regression equation based on their partial correlation coefficient and confidence level. The regression equations developed had correlation coefficients of 0.87 to 1.00, which was much better than the correlation coefficient (0.84) of an existing model DeGeare and Ongerth (1971) and a correlation coefficient of 0.54 based on the current solid waste disposal tax. (author)

Bioelectrochemically-assisted anaerobic composting process enhancing compost maturity of dewatered sludge with synchronous electricity generation.

Science.gov (United States)

Yu, Hang; Jiang, Junqiu; Zhao, Qingliang; Wang, Kun; Zhang, Yunshu; Zheng, Zhen; Hao, Xiaodi

2015-10-01

Bioelectrochemically-assisted anaerobic composting process (AnCBE) with dewatered sludge as the anode fuel was constructed to accelerate composting of dewatered sludge, which could increase the quality of the compost and harvest electric energy in comparison with the traditional anaerobic composting (AnC). Results revealed that the AnCBE yielded a voltage of 0.60 ± 0.02 V, and total COD (TCOD) removal reached 19.8 ± 0.2% at the end of 35 d. The maximum power density was 5.6 W/m(3). At the end of composting, organic matter content (OM) reduction rate increased to 19.5 ± 0.2% in AnCBE and to 12.9 ± 0.1% in AnC. The fuzzy comprehensive assessment (FCA) result indicated that the membership degree of class I of AnCBE compost (0.64) was higher than that of AnC compost (0.44). It was demonstrated that electrogenesis in the AnCBE could improve the sludge stabilization degree, accelerate anaerobic composting process and enhance composting maturity with bioelectricity generation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hydrogen production during processing of radioactive sludge containing noble metals

International Nuclear Information System (INIS)

Ha, B.C.; Ferrara, D.M.; Bibler, N.E.

1992-01-01

Hydrogen was produced when radioactive sludge from Savannah River Site radioactive waste containing noble metals was reacted with formic acid. This will occur in a process tank in the Defense Waste Facility at SRS when waste is vitrified. Radioactive sludges from four tanks were tested in a lab-scale apparatus. Maximum hydrogen generation rates varied from 5 x10 -7 g H 2 /hr/g of sludge from the least reactive sludge (from Waste Tank 51) to 2 x10 -4 g H 2 /hr/g of sludge from the most reactive sludge (from Waste Tank 11). The time required for the hydrogen generation to reach a maximum varied from 4.1 to 25 hours. In addition to hydrogen, carbon dioxide and nitrous oxide were produced and the pH of the reaction slurry increased. In all cases, the carbon dioxide and nitrous oxide were generated before the hydrogen. The results are in agreement with large-scale studies using simulated sludges

Effects of moisture content on long-term survival and regrowth of bacteria in wastewater sludge

Energy Technology Data Exchange (ETDEWEB)

Yeager, J.G. (BDM Corp., Albuquerque, NM); Ward, R.L.

1981-05-01

The effects of moisture content on the survival and regrowth of seeded and indigenous enteric bacteria in raw sludge were determined. Cultures of six strains of fecally associated bacteria grown in sterilized, liquid sludge (5% solids) were all quite stable at this moisture level for over 90 days at 21/sup 0/C. When the moisture content of the sludge containing these organisms was reduced by evaporation and the samples were stored at 21/sup 0/C for extended periods, bacterial inactivation rates were generally proportional to the moisture losses of the samples. A dramatic reversal in this effect was observed in samples containing more than 90% solids. In this dried sludge, every bacterial species studied except Proteus mirabilis was found to be extremely stable. Bacteria indigenous to sludge were also found to survive for long periods in dried sludge. Growth of seeded Salmonella typhimurium was also found to occur in the presence of indigenous organisms in both liquid and dewatered raw sludges. However, the population density attained was well below that found in sterilized samples of the same sludges.

Application of the International Water Association activated sludge models to describe aerobic sludge digestion.

Science.gov (United States)

Ghorbani, M; Eskicioglu, C

2011-12-01

Batch and semi-continuous flow aerobic digesters were used to stabilize thickened waste-activated sludge at different initial conditions and mean solids retention times. Under dynamic conditions, total suspended solids, volatile suspended solids (VSS) and total and particulate chemical oxygen demand (COD and PCOD) were monitored in the batch reactors and effluent from the semi-continuous flow reactors. Activated Sludge Model (ASM) no. 1 and ASM no. 3 were applied to measured data (calibration data set) to evaluate the consistency and performances of models at different flow regimes for digester COD and VSS modelling. The results indicated that both ASM1 and ASM3 predicted digester COD, VSS and PCOD concentrations well (R2, Ra2 > or = 0.93). Parameter estimation concluded that compared to ASM1, ASM3 parameters were more consistent across different batch and semi-continuous flow runs with different operating conditions. Model validation on a data set independent from the calibration data successfully predicted digester COD (R2 = 0.88) and VSS (R2 = 0.94) concentrations by ASM3, while ASM1 overestimated both reactor COD (R2 = 0.74) and VSS concentrations (R2 = 0.79) after 15 days of aerobic batch digestion.

Sludge Treatment Project Engineered Container Retrieval And Transfer System Prelminary Design Hazard And Operability Study

International Nuclear Information System (INIS)

Carro, C.A.

2011-01-01

This Hazard and Operability (HAZOP) study addresses the Sludge Treatment Project (STP) Engineered Container Retrieval and Transfer System (ECRTS) preliminary design for retrieving sludge from underwater engineered containers located in the 105-K West (KW) Basin, transferring the sludge as a sludge-water slurry (hereafter referred to as 'slurry') to a Sludge Transport and Storage Container (STSC) located in a Modified KW Basin Annex, and preparing the STSC for transport to T Plant using the Sludge Transport System (STS). There are six, underwater engineered containers located in the KW Basin that, at the time of sludge retrieval, will contain an estimated volume of 5.2 m 3 of KW Basin floor and pit sludge, 18.4 m 3 of 105-K East (KE) Basin floor, pit, and canister sludge, and 3.5 m 3 of settler tank sludge. The KE and KW Basin sludge consists of fuel corrosion products (including metallic uranium, and fission and activation products), small fuel fragments, iron and aluminum oxide, sand, dirt, operational debris, and biological debris. The settler tank sludge consists of sludge generated by the washing of KE and KW Basin fuel in the Primary Clean Machine. A detailed description of the origin of sludge and its chemical and physical characteristics can be found in HNF-41051, Preliminary STP Container and Settler Sludge Process System Description and Material Balance. In summary, the ECRTS retrieves sludge from the engineered containers and hydraulically transfers it as a slurry into an STSC positioned within a trailer-mounted STS cask located in a Modified KW Basin Annex. The slurry is allowed to settle within the STSC to concentrate the solids and clarify the supernate. After a prescribed settling period the supernate is decanted. The decanted supernate is filtered through a sand filter and returned to the basin. Subsequent batches of slurry are added to the STSC, settled, and excess supernate removed until the prescribed quantity of sludge is collected. The sand

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

Solid-phase characterization in flammable-gas-tank sludges by electron microscopy

International Nuclear Information System (INIS)

Liu, J.; Pederson, L.R.; Qang, L.Q.

1995-09-01

The crystallinity, morphology, chemical composition, and crystalline phases of several Tank 241-SY-101 (hereinafter referred to as SY-101) and Tank 241-SY-103 (hereinafter referred to as SY-103) solid samples were studied by transmission electron microscopy (TEM), electron energy dispersive spectroscopy (EDS), and electron diffraction. The main focus is on the identification of aluminum hydroxide thought to be present in these tank samples. Aluminum hydroxide was found in SY-103, but not in SY-101. This difference can be explained by the different OH/Al ratios found in the two tank samples: a high OH/Al ratio in SY-101 favors the formation of sodium aluminate, but a low OH/Al ratio in SY-103 favors aluminum hydroxide. These results were confirmed by a magnetic resonance study on SY-101 and SY-103 simulant. The transition from aluminum hydroxide to sodium aluminate occurs at an OH/Al molar ratio of 3.6. It is believed that the study of Al(OH) 3 was not affected by sample preparation because all Al(OH) 3 is in the solid form according to the NMR experiments. There is no Al(OH) 3 in the liquid. It is, therefore, most likely that the observation of Al(OH) 3 is representative of the real sludge sample, and is not affected by drying. Similar conclusions also apply to other insoluble phases such as iron and chromium

Immobilization of radioactive waste sludge from spent fuel storage pool

International Nuclear Information System (INIS)

Pavlovic, R.; Plecas, I.

1998-01-01

In the last forty years, in FR Yugoslavia, as result of the research reactors' operation and radionuclides application in medicine, industry and agriculture, radioactive waste materials of the different categories and various levels of specific activities were generated. As a temporary solution, these radioactive waste materials are stored in the two hanger type interim storages for solid waste and some type of liquid waste packed in plastic barrels, and one of three stainless steal underground containers for other types of liquid waste. Spent fuel elements from nuclear reactors in the Vinca Institute have been temporary stored in water filled storage pool. Due to the fact that the water in the spent fuel elements storage pool have not been purified for a long time, all metallic components submerged in the water have been hardly corroded and significant amount of the sludge has been settled on the bottom of the pool. As a first step in improving spent fuel elements storage conditions and slowing down corrosion in the storage spent fuel elements pool we have decided to remove the sludge from the bottom of the pool. Although not high, but slightly radioactive, this sludge had to be treated as radioactive waste material. Some aspects of immobilisation, conditioning and storage of this sludge are presented in this paper. (author

Construction materials as a waste management solution for cellulose sludge.

Science.gov (United States)

Modolo, R; Ferreira, V M; Machado, L M; Rodrigues, M; Coelho, I

2011-02-01

Sustainable waste management system for effluents treatment sludge has been a pressing issue for pulp and paper sector. Recycling is always recommended in terms of environmental sustainability. Following an approach of waste valorisation, this work aims to demonstrate the technical viability of producing fiber-cement roof sheets incorporating cellulose primary sludge generated on paper and pulp mills. From the results obtained with preliminary studies it was possible to verify the possibility of producing fiber-cement sheets by replacing 25% of the conventional used virgin long fiber by primary effluent treatment cellulose sludge. This amount of incorporation was tested on an industrial scale. Environmental parameters related to water and waste, as well as tests for checking the quality of the final product was performed. These control parameters involved total solids in suspension, dissolved salts, chlorides, sulphates, COD, metals content. In the product, parameters like moisture, density and strength were controlled. The results showed that it is possible to replace the virgin long fibers pulp by primary sludge without impacts in final product characteristics and on the environment. This work ensures the elimination of significant waste amounts, which are nowadays sent to landfill, as well as reduces costs associated with the standard raw materials use in the fiber-cement industrial sector. Copyright © 2010 Elsevier Ltd. All rights reserved.

Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

DEFF Research Database (Denmark)

Falås, Per; Baillon-Dhumez, Aude; Andersen, Henrik Rasmus

2012-01-01

Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct...... and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast...

Modelling of sludge blanket height and flow pattern in UASB reactors treating municipal wastewater

International Nuclear Information System (INIS)

Singh, K.S.; Viraraghavan, T.

2002-01-01

Two upflow anaerobic sludge blanket (UASB) reactors were started-up and operated for approximately 900 days to examine the feasibility of treating municipal wastewater under low temperature conditions. A modified solid distribution model was formulated by incorporating the variation of biogas production rate with a change in temperature. This model was used to optimize the sludge blanket height of UASB reactors for an effective operation of gas-liquid-solid (GLS) separation device. This model was found to simulate well the solid distribution as confirmed experimental observation of solid profile along the height of the reactor. Mathematical analysis of tracer curves indicated the presence of a mixed type of flow pattern in the sludge-bed zone of the reactor. It was found that the dead-zone and by-pass flow fraction were impacted by the change in operating temperatures. (author)

TEMPEST code modifications and testing for erosion-resisting sludge simulations

International Nuclear Information System (INIS)

Onishi, Y.; Trent, D.S.

1998-01-01

The TEMPEST computer code has been used to address many waste retrieval operational and safety questions regarding waste mobilization, mixing, and gas retention. Because the amount of sludge retrieved from the tank is directly related to the sludge yield strength and the shear stress acting upon it, it is important to incorporate the sludge yield strength into simulations of erosion-resisting tank waste retrieval operations. This report describes current efforts to modify the TEMPEST code to simulate pump jet mixing of erosion-resisting tank wastes and the models used to test for erosion of waste sludge with yield strength. Test results for solid deposition and diluent/slurry jet injection into sludge layers in simplified tank conditions show that the modified TEMPEST code has a basic ability to simulate both the mobility and immobility of the sludges with yield strength. Further testing, modification, calibration, and verification of the sludge mobilization/immobilization model are planned using erosion data as they apply to waste tank sludges

Development of bricks with incorporation of coal ash and sludge from water treatment plant

International Nuclear Information System (INIS)

Silva, Mauro Valerio da

2011-01-01

Sludge from treatment water Brazilian plant station are, frequently, disposed and launched directly in the water bodies, causing a negative impact in the environment. Also, coal ashes is produced by burning of coal in coal-fired power stations and is the industrial solid waste most generated in southern Brazil: approximately 4 million tons/y. The efficient disposal of coal ashes is an issue due to its massive volume and harmful risks to the environment. The aim of this work was study the feasibility of incorporating these two industrial wastes in a mass used in the manufacture of ecological bricks. Samples of fly ashes from a cyclone filter from a coal-fired power plant located at Figueira County in Parana State, Brazil and waterworks sludge of Terra Preta County in Sao Paulo State, Brazil, were used in the study. Fly ash-sludge and fly ash-sludge-soil-cement bricks were molded and tested, according to the Brazilians Standards. The materials were characterized by physical-chemical analysis, X-ray diffraction, thermal analysis, morphological analysis, Fourier transform infrared spectroscopy and granulometric analysis. The results indicate that the waterworks sludge and coal ashes have potential to be used on manufacturing soil-cement pressed bricks according to the of Brazilians Standards NBR 10836/94. (author)

Microbiological characterization and specific methanogenic activity of anaerobe sludges used in urban solid waste treatment

International Nuclear Information System (INIS)

Sandoval Lozano, Claudia Johanna; Vergara Mendoza, Marisol; Carreno de Arango, Mariela; Castillo Monroy, Edgar Fernando

2009-01-01

This study presents the microbiological characterization of the anaerobic sludge used in a two-stage anaerobic reactor for the treatment of organic fraction of urban solid waste (OFUSW). This treatment is one alternative for reducing solid waste in landfills at the same time producing a biogas (CH 4 and CO 2 ) and an effluent that can be used as biofertilizer. The system was inoculated with sludge from a wastewater treatment plant (WWTP) (Rio Frio Plant in Bucaramanga-Colombia) and a methanogenic anaerobic digester for the treatment of pig manure (Mesa de los Santos in Santander). Bacterial populations were evaluated by counting groups related to oxygen sensitivity, while metabolic groups were determined by most probable number (MPN) technique. Specific methanogenic activity (SMA) for acetate, formate, methanol and ethanol substrates was also determined. In the acidogenic reactor (R1), volatile fatty acids (VFA) reached values of 25,000 mg L -1 and a concentration of CO 2 of 90%. In this reactor, the fermentative population was predominant (10 5 -10 6 MPN mL -1 ). The acetogenic population was (10 5 MPN mL -1 ) and the sulphate-reducing population was (10 4 -10 5 MPN mL -1 ). In the methanogenic reactor (R2), levels of CH 4 (70%) were higher than CO 2 (25%), whereas the VFA values were lower than 4000 mg L -1 . Substrate competition between sulphate-reducing (10 4 -10 5 MPN mL -1 ) and methanogenic bacteria (10 5 MPN mL -1 ) was not detected. From the SMA results obtained, acetoclastic (2.39 g COD-CH 4 g -1 VSS -1 day -1 ) and hydrogenophilic (0.94 g COD-CH 4 g -1 VSS -1 day -1 ) transformations as possible metabolic pathways used by methanogenic bacteria is suggested from the SMA results obtained. Methanotrix sp., Methanosarcina sp., Methanoccocus sp. and Methanobacterium sp. were identified

Influence of ultrasonication and Fenton oxidation pre-treatment on rheological characteristics of wastewater sludge.

Science.gov (United States)

Pham, T T H; Brar, S K; Tyagi, R D; Surampalli, R Y

2010-01-01

The effect of ultrasonication and Fenton oxidation as physico-chemical pre-treatment processes on the change of rheology of wastewater sludge was investigated in this study. Pre-treated and raw sludges displayed non-Newtonian rheological behaviour with shear thinning as well as thixotropic properties for total solids ranging from 10 g/L to 40 g/L. The rheological models, namely, Bingham plastic, Casson law, NCA/CMA Casson, IPC Paste, and power law were also studied to characterize flow of raw and pre-treated sludges. Among all rheological models, the power law was more prominent in describing the rheology of the sludges. Pre-treatment processes resulted in a decrease in pseudoplasticity of sludge due to the decrease in consistency index K varying from 42.4 to 1188, 25.6 to 620.4 and 52.5 to 317.9; and increase in flow behaviour index n changing from 0.5 to 0.35, 0.62 to 0.55 and 0.63 to 0.58, for RS, UlS and FS, respectively at solids concentration 10-40 g/L. The correlation between improvement of biodegradability and dewaterability, decrease in viscosity, and change in particle size as a function of sludge pre-treatment process was also investigated. Fenton oxidation facilitated sludge filterability resulting in capillary suction time values which were approximately 50% of the raw sludges, whereas ultrasonication with high input energy deteriorated the filterability. Biodegradability was also enhanced by the pre-treatment processes and the maximum value was obtained (64%, 77% and 73% for raw, ultrasonicated and Fenton oxidized sludges, respectively) at total solids concentration of 25 g/L. Hence, pre-treatment of wastewater sludge modified the rheological properties so that: (1) the flowability of sludge was improved for transport through the treatment train (via pipes and pumps); (2) the dewaterability of wastewater sludge was enhanced for eventual disposal and; (3) the assimilation of nutrients by microorganisms for further value-addition was increased.

Organic matter and heavy metals in grey-water sludge | Eriksson ...

African Journals Online (AJOL)

Grey-water intended for non-potable reuse is being intensively studied, but little attention has been given to the associated solid fraction, the grey-water sludge. In this study grey-water sludge originating from bathroom grey-water has been screened with respect to organic matter; particles; short-chain fatty alcohols and ...

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.

Validation Testing of the Nitric Acid Dissolution Step Within the K Basin Sludge Pretreatment Process

International Nuclear Information System (INIS)

AJ Schmidt; CH Delegard; KL Silvers; PR Bredt; CD Carlson; EW Hoppe; JC Hayes; DE Rinehart; SR Gano; BM Thornton

1999-01-01

solutions as a function of reaction (dissolution) time, by analyzing offgas generation rate and composition, and by analyzing intermittent and final acid-insoluble solids at the end of the dissolution. The testing was conducted in a system designed to assess parameters that can influence sludge dissolution and provide information that can be used to determine operating conditions for the actual system

Validation Testing of the Nitric Acid Dissolution Step Within the K Basin Sludge Pretreatment Process

Energy Technology Data Exchange (ETDEWEB)

AJ Schmidt; CH Delegard; KL Silvers; PR Bredt; CD Carlson; EW Hoppe; JC Hayes; DE Rinehart; SR Gano; BM Thornton

1999-03-24

dissolver solutions as a function of reaction (dissolution) time, by analyzing offgas generation rate and composition, and by analyzing intermittent and final acid-insoluble solids at the end of the dissolution. The testing was conducted in a system designed to assess parameters that can influence sludge dissolution and provide information that can be used to determine operating conditions for the actual system.

Influence of deflocculation on microwave disintegration and anaerobic biodegradability of waste activated sludge.

Science.gov (United States)

Ebenezer, A Vimala; Kaliappan, S; Adish Kumar, S; Yeom, Ick-Tae; Banu, J Rajesh

2015-06-01

In the present study, the potential benefits of deflocculation on microwave pretreatment of waste activated sludge were investigated. Deflocculation in the absence of cell lysis was achieved through the removal of extra polymeric substances (EPS) by sodium citrate (0.1g sodium citrate/g suspended solids), and DNA was used as a marker for monitoring cell lysis. Subsequent microwave pretreatment yielded a chemical oxygen demand (COD) solubilisation of 31% and 21%, suspended solids (SS) reduction of 37% and 22%, for deflocculated and flocculated sludge, respectively, with energy input of 14,000kJ/kg TS. When microwave pretreated sludge was subjected to anaerobic fermentation, greater accumulation of volatile fatty acid (860mg/L) was noticed in deflocculated sludge, indicating better hydrolysis. Among the samples subjected to BMP (Biochemical methane potential test), deflocculated microwave pretreated sludge showed better amenability towards anaerobic digestion with high methane production potential of 0.615L (gVS)(-1). Copyright © 2015 Elsevier Ltd. All rights reserved.

Counter current decantation washing of HLW sludge

International Nuclear Information System (INIS)

Brooke, J.N.; Peterson, R.A.

1997-01-01

The Savannah River Site (SRS) has 51 High Level Waste (HLW) tanks with typical dimensions 25.9 meters (85 feet) diameter and 10 meters (33 feet) high. Nearly 114 million liters (30 M gallons) of HLW waste is stored in these tanks in the form of insoluble solids called sludge, crystallized salt called salt cake, and salt solutions. This waste is being converted to waste forms stable for long term storage. In one of the processes, soluble salts are washed from HLW sludge in preparation for vitrification. At present, sludge is batch washed in a waste tank with one or no reuse of the wash water. Sodium hydroxide and sodium nitrite are added to the wash water for tank corrosion protection; the large volumes of spent wash water are recycled to the evaporator system; additional salt cake is produced; and sodium carbonate is formed in the washed sludge during storage by reaction with CO 2 from the air. High costs and operational concerns with the current washing process prompts DOE and WSRC to seek an improved washing method. A new method should take full advantage of the physical/chemical properties of sludge, experience from other technical disciplines, processing rate requirements, inherent process safety, and use of proven processes and equipment. Counter current solids washing is a common process in the minerals processing and chemical industries. Washing circuits can be designed using thickeners, filters or centrifuges. Realizing the special needs of nuclear work and the low processing rates required, a Counter Current Decantation (CCD) circuit is proposed using small thickeners and fluidic pumps

K Basin Sludge Conditioning Process Testing Partitioning of PCBs in Dissolver Solution After Neutralization/Precipitation (Caustic Adjustment)

International Nuclear Information System (INIS)

Schmidt, A.J.; Thornton, B.M.; Hoppe, E.W.; Mong, G.M.; Silvers, K.L.; Slate, S.O.

1999-01-01

The purpose of the work described in this report was to gain a better understanding of how PCB congeners present in a simulated K Basin sludge dissolver solution will partition upon neutralization and precipitation (i.e., caustic adjustment). In a previous study (Mong et al. 1998),the entire series of sludge conditioning steps (acid dissolution, filtration, and caustic adjustment) were examined during integrated testing. In the work described here, the caustic adjustment step was isolated to examine the fate of PCBs in more detail within this processing step. For this testing, solutions of dissolver simulant (containing no solids) with a known initial concentration of PCB congeners were neutralized with caustic to generate a clarified supernatant and a settled sludge phase. PCBs were quantified in each phase (including the PCBs associated with the test vessel rinsates), and material balance information was collected

Potential priority pollutants in sewage sludge

DEFF Research Database (Denmark)

Eriksson, Eva; Christensen, Nina; Schmidt, Jens Ejbye

2008-01-01

compounds using their inherent properties and environmental fate it was shown that 99 XOCs could be classified as being hazardous with regard to the solid phase and 23 were found to be priority pollutants in the subsequent hazard assessment. The final selected priority pollutants can act as indicators when...... assessing sludge quality. They were compared with European legislations and discussed in regard for pointing out the need for mitigation such as substitution. Furthermore, the potential need for implementation of sludge treatment trains in order to meet the society's needs was addressed....

[Analysis of carbon balance and study on mechanism in anoxic-oxic-settling-anaerobic sludge reduction process].

Science.gov (United States)

Zhai, Xiao-Min; Gao, Xu; Zhang, Man-Man; Jia, Li; Guo, Jin-Song

2012-07-01

In order to deeply explore the mechanism of sludge reduction in OSA system, carbon balance was performed in an anoxic-oxic-settling-anaerobic (A + OSA) system and a reference AO system to investigate effects of inserting a sludge holding tank in sludge cycle line on the sludge reduction process. Meanwhile, carbon mass change in each reaction unit was identified in terms of solid, liquid and gas phases. The causes of excess sludge reduction in A + OSA system were deduced. The carbon balance results show that when the hydraulic retention time in the sludge holding tank is 7.14 h, carbon percent in solid phase of the sludge reduction system is nearly 50% higher than that of the reference system, supporting the consequence that sludge reduction rate of 49.98% had been achieved. The insertion of a sludge holding tank in the sludge return circuit can be effective in sludge reduction. Carbon changes in each unit reveal that the amount of carbon consumed for biosynthesis in the anoxic and oxic tanks (main reaction zone) of the sludge reduction system is higher than in that of the reference system. Sludge decay is observed in the sludge holding tank. Furthermore, CH4 released from the sludge holding tank is significantly higher than that from the main reaction zone. The DGGE profiles show that there are hydrolytic-fermentative bacteria in the sludge holding tank related to sludge decay. The excess sludge reduction in the A + OSA system could be a result of the combination of sludge decay in the sludge holding tank and sludge compensatory growth in the main reaction cell.

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

Bench-Scale Evaluation of Hydrothermal Processing Technology for Conversion of Wastewater Solids to Fuels

Energy Technology Data Exchange (ETDEWEB)

Marrone, Philip A.; Elliott, Douglas C.; Billing, Justin M.; Hallen, Richard T.; Hart, Todd R.; Kadota, Paul; Moeller, Jeff C.; Randel, Margaaret A.; Schmidt, Andrew J.

2018-04-01

Hydrothermal Liquefaction (HTL) and Catalytic Hydrothermal Gasification (CHG) proof-of-concept bench-scale tests were performed to assess the potential of hydrothermal treatment for handling municipal wastewater sludge. HTL tests were conducted at 300-350°C and 20 MPa on three different feeds: primary sludge, secondary sludge, and digested solids. Corresponding CHG tests were conducted at 350°C and 20 MPa on the HTL aqueous phase output using a ruthenium based catalyst. Biocrude yields ranged from 25-37%. Biocrude composition and quality were comparable to biocrudes generated from algae feeds. Subsequent hydrotreating of biocrude resulted in a product with comparable physical and chemical properties to crude oil. CHG product gas methane yields on a carbon basis ranged from 47-64%. Siloxane concentrations in the CHG product gas were below engine limits. The HTL-CHG process resulted in a chemical oxygen demand (COD) reduction of > 99.9% and a reduction in residual solids for disposal of 94-99%.

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

System for removing sludges from a steam generator

International Nuclear Information System (INIS)

Hickman, R.A.; Tolino, R.W.

1977-01-01

The invention relates to a process for removing sludge from a steam generator comprising a tube plate at the bottom end of a cylinder and a cluster of heat exchange tubes fitted to this tube plate and extending upwards from it. The cylinder has an access opening above this tube plate. A liquid jet is applied at a tangent to the cylinder above the tube plate so as to form a cicumferential flow of liquid at the external end of this plate. This flow is taken up and sucked out of the cylinder by a suction appliance and, at the same time, a nozzle with holes for liquid jets is moved crosswise to these tubes above the tube plate whilst directing a liquid jet against the tubes and towards the cicumferential liquid flow so as to wash away any deposits detached from the lower ends of the tubes and located in this circular flow of liquid to be immediately removed by the suction appliance [fr

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

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.)

Submersible microbial fuel cell for electricity production from sewage sludge

DEFF Research Database (Denmark)

Zhang, Yifeng; Olias, Lola Gonzalez; Kongjan, Prawit

2010-01-01

A submersible microbial fuel cell (SMFC) was utilized to treatment of sewage sludge and simultaneous generate electricity. Stable power generation (145±5 mW/m2) was produced continuously from raw sewage sludge for 5.5 days. The corresponding total chemical oxygen demand (TCOD) removal efficiency...... of an effective system to treatment of sewage sludge and simultaneous recover energy....

Submersible microbial fuel cell for electricity production from sewage sludge

DEFF Research Database (Denmark)

Zhang, Yifeng; Olias, Lola Gonzalez; Kongjan, Prawit

2011-01-01

A submersible microbial fuel cell (SMFC) was utilized to treat sewage sludge and simultaneously generate electricity. Stable power generation (145± 5 mW/m2, 470 Ω) was produced continuously from raw sewage sludge for 5.5 days. The maximum power density reached 190±5 mW/m2. The corresponding total...... system to treat sewage sludge and simultaneously recover energy....

Evaluation of sludge properties in a pilot-scale UASB reactor for sewage treatment in a temperate region.

Science.gov (United States)

Syutsubo, K; Yoochatchaval, W; Tsushima, I; Araki, N; Kubota, K; Onodera, T; Takahashi, M; Yamaguchi, T; Yoneyama, Y

2011-01-01

In this study, continuous operation of a pilot-scale upflow anaerobic sludge blanket (UASB) reactor for sewage treatment was conducted for 630 days to investigate the physical and microbial characteristics of the retained sludge. The UASB reactor with a working volume of 20.2 m(3) was operated at ambient temperature (16-29 °C) and seeded with digested sludge. After 180 days of operation, when the sewage temperature had dropped to 20 °C or lower, the removal efficiency of both total suspended solids (TSS) and total biochemical oxygen demand (BOD) deteriorated due to washout of retained sludge. At low temperature, the cellulose concentration of the UASB sludge increased owing to the rate limitation of the hydrolytic reaction of suspended solids in the sewage. However, after an improvement in sludge retention (settleability and concentration) in the UASB reactor, the process performance stabilized and gave sufficient results (68% of TSS removal, 75% of total BOD removal) at an hydraulic retention time (HRT) of 9.7 h. The methanogenic activity of the retained sludge significantly increased after day 246 due to the accumulation of Methanosaeta and Methanobacterium following the improvement in sludge retention in the UASB reactor. Acid-forming bacteria from phylum Bacteroidetes were detected at high frequency; thus, these bacteria may have an important role in suspended solids degradation.

Simulation of sludge deposit onto a 900 MW steam generator tubesheet with the 3D code GENEPI

International Nuclear Information System (INIS)

Pascal-Ribot, S.; Debec-Mathet, E.; Soussan, D.; Grandotto, M.

1998-01-01

Heat transfer processes use fluids which are generally not pure and can react with transfer surfaces. These surfaces are subject to deposits which can be sediments harmful to heat transfer and to integrity of materials. For nuclear plant steam generators, sludge build-up accelerates secondary side corrosion by concentrating chemical species. A major safety problem involved with such a corrosion is the growing of circumferential cracks which are very difficult to detect and size with eddy current probes. With a view to understand and control this problem, it is necessary to develop a mathematical model for the prediction of sludge behavior in PWR steam generators. Based on fundamental principles, this work intends to use different models available in literature for the prediction of the phenomenon leading to the accumulation of sludge particles at the bottom (the tubesheet) of a PWR. For that, a three-dimensional simulation of magnetite particulate fouling with the finite elements code GENEPI is performed on a 900 MWe steam generator. The use of GENEPI code, originally designed and qualified for the analysis of steam generators thermalhydraulics is done in two steps. First, the local thermalhydraulic conditions of the carrier phase are calculated with the classical conservation equations of mass, momentum and enthalpy for the steam/water mixture (homogeneous model). Then, they are used for the solving of a particle transport equation. The mass transfer processes, which have been taken into account, are gravitational settling, sticking probability and reentrainment describing respectively the transport of sludge particles to the tubesheet, the particle attachment to this surface and the re-suspension of deposited particles from the tubesheet. A sink term characterizing the blowdown effect is also considered in the calculations. Deposition on the tube bundle surface area is not modelled. For this first approach, the simulation is made with a single particle size and

Effect of municipal solid waste compost and sewage sludge on yield and heavy metal accumulation in soil and black cumin (Nigella sativa L.

Directory of Open Access Journals (Sweden)

F. Akbarnejad

2016-04-01

Full Text Available In order to investigate the effect of municipal solid waste (MSw compost and sewage sludge (SS on yield and concentration of heavy metals in soil and black cumin (Nigella sativa L. an experiment with MSW compost at 0, 15, 30 t.ha-1 (C0, C15 and C30 and sewage sludge at 0, 15, 30 t.ha-1 (S0, S15 and S30 in a factorial experiment based on completely randomized design with three replications was conducted in greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. Results showed that MSW compost and SS had significant effects on plant dry matter. Increasing the amounts of SS increased dry matter of plant. But increasing MSW compost from 15 to 30 t.ha-1 was decreased in dry matter. The Effect of MSW compost and SS on concentration of heavy metals (Ni and Pb in plant except Cd was significant. Addition of MSW compost and sewage sludge increased availability of Pb, Ni and Cd in soil. But effect of MSW compost and sewage sludge on Cd availability was not significant. Results showed that the amounts of Ni exceed the standard limits in dry matter. Therefore in use of organic wastes for medicinal plants we should be careful..

Fungal treatment: a prospective process for eco-friendly bioremediation of wastewater sludge

International Nuclear Information System (INIS)

Molla, A. H.; Fakhru'l-Razi, A.

2009-01-01

None of the conventional techniques is safe and environmental friendly for wastewaters/sludge disposal. A sustainable, safe and environmental friendly biological technique is a great apprehension to the relevant scientists. Since the fungal treatment was exercised to evaluate its potentially for sustainable bioseparation and bioremediation of wastewater. Bioseparation and bioremediation of wastewater sludge by fungal inoculation implied the decreasing of bio solids, total suspended solids (TSS), turbidity, chemical oxygen demand (COD) and specific resistance to filtration (SRF) of wastewater. (Author)

Performance indicators and indices of sludge management in urban wastewater treatment plants.

Science.gov (United States)

Silva, C; Saldanha Matos, J; Rosa, M J

2016-12-15

Sludge (or biosolids) management is highly complex and has a significant cost associated with the biosolids disposal, as well as with the energy and flocculant consumption in the sludge processing units. The sludge management performance indicators (PIs) and indices (PXs) are thus core measures of the performance assessment system developed for urban wastewater treatment plants (WWTPs). The key PIs proposed cover the sludge unit production and dry solids concentration (DS), disposal/beneficial use, quality compliance for agricultural use and costs, whereas the complementary PIs assess the plant reliability and the chemical reagents' use. A key PI was also developed for assessing the phosphorus reclamation, namely through the beneficial use of the biosolids and the reclaimed water in agriculture. The results of a field study with 17 Portuguese urban WWTPs in a 5-year period were used to derive the PI reference values which are neither inherent to the PI formulation nor literature-based. Clusters by sludge type (primary, activated, trickling filter and mixed sludge) and by digestion and dewatering processes were analysed and the reference values for sludge production and dry solids were proposed for two clusters: activated sludge or biofilter WWTPs with primary sedimentation, sludge anaerobic digestion and centrifuge dewatering; activated sludge WWTPs without primary sedimentation and anaerobic digestion and with centrifuge dewatering. The key PXs are computed for the DS after each processing unit and the complementary PXs for the energy consumption and the operating conditions DS-determining. The PX reference values are treatment specific and literature based. The PI and PX system was applied to a WWTP and the results demonstrate that it diagnosis the situation and indicates opportunities and measures for improving the WWTP performance in sludge management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sludge reduction by ozone: Insights and modeling of the dose-response effects.

Science.gov (United States)

Fall, C; Silva-Hernández, B C; Hooijmans, C M; Lopez-Vazquez, C M; Esparza-Soto, M; Lucero-Chávez, M; van Loosdrecht, M C M

2018-01-15

Applying ozone to the return flow in an activated sludge (AS) process is a way for reducing the residual solids production. To be able to extend the activated sludge models to the ozone-AS process, adequate prediction of the tri-atoms effects on the particulate COD fractions is needed. In this study, the biomass inactivation, COD mineralization, and solids dissolution were quantified in batch tests and dose-response models were developed as a function of the reacted ozone doses (ROD). Three kinds of model-sludge were used. S1 was a lab-cultivated synthetic sludge with two components (heterotrophs X H and X P ). S2 was a digestate of S1 almost made by the endogenous residues, X P . S3 was from a municipal activated sludge plant. The specific ozone uptake rate (SO 3 UR, mgO 3 /gCOD.h) was determined as a tool for characterizing the reactivity of the sludges. SO 3 UR increased with the X H fraction and decreased with more X P . Biomass inactivation was exponential (e -β.ROD ) as a function of the ROD doses. The percentage of solids reduction was predictable through a linear model (C Miner  + Y sol ROD), with a fixed part due to mineralization (C Miner ) and a variable part from the solubilization process. The parameters of the models, i.e. the inactivation and the dissolution yields (β, 0.008-0.029 (mgO 3 /mgCOD ini ) -1 vs Y sol , 0.5-2.8 mg COD sol /mgO 3 ) varied in magnitude, depending on the intensity of the scavenging reactions and potentially the compactness of the flocs for each sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Research results of sewage sludge and waste oil disposal by entrained bed gasification

Energy Technology Data Exchange (ETDEWEB)

Schingnitz, M.; Goehler, P.; Wenzel, W.; Seidel, W. (Noell-DBI Energie- und Entsorgungstechnik GmbH, Freiberg (Germany))

1992-01-01

Presents results of gasifying sewage sludge and waste oil with the GSP technology, developed by the Freiberg Fuel Institute (FRG). The GSP reactor was developed in 1976 for gasification of pulverized brown coal. An industrial reactor of this design operated for over 5 years with a total coal throughput of more than 300,000 t. The design of the gasification generator and the flowsheet of a 3 MW experimental pilot plant for waste gasification are presented. The PCB content in the gasification sludge is 6.14 mg/kg, in waste oil - 160 mg/kg. Gasification takes place at high temperatures of more than 1,400 C for complete destruction of toxic pollutants. Gasification results compare composition of raw gas produced by gasification of brown coal, sewage sludge and waste oil. A detailed list of content of pollutants (PCDD, PCDF, PAH, dioxin and furan) in the gasification gas, in process waters and in solid residue of the process water is provided. It is concluded that the GSP gasification process is suitable for safe disposal of waste with toxic content. 3 refs.

Concentrations and environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks and accumulation in sludge, New Jersey Coastal Plain, USA

Science.gov (United States)

Szabo, Z.; Jacobsen, E.; Kraemer, T.F.; Parsa, B.

2008-01-01

Concentrations of Ra in liquid and solid wastes generated from 15 softeners treating domestic well waters from New Jersey Coastal Plain aquifers (where combined Ra (226Ra plus 228Ra) concentrations commonly exceed 0.185 Bq L-1) were determined. Softeners, when maintained, reduced combined Ra about 10-fold (septic-tank effluents receiving brine waste were less than in the untreated ground waters. The maximum combined Ra concentration in aquifer sands (40.7 Bq kg-1 dry weight) was less than that in sludge from the septic tanks (range, 84-363 Bq kg-1), indicating Ra accumulation in sludge from effluent. The combined Ra concentration in sludge from the homeowners' septic systems falls within the range reported for sludge samples from publicly owned treatment works within the region.

SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY

Energy Technology Data Exchange (ETDEWEB)

CARRO CA

2011-07-15

This Hazard and Operability (HAZOP) study addresses the Sludge Treatment Project (STP) Engineered Container Retrieval and Transfer System (ECRTS) preliminary design for retrieving sludge from underwater engineered containers located in the 105-K West (KW) Basin, transferring the sludge as a sludge-water slurry (hereafter referred to as 'slurry') to a Sludge Transport and Storage Container (STSC) located in a Modified KW Basin Annex, and preparing the STSC for transport to T Plant using the Sludge Transport System (STS). There are six, underwater engineered containers located in the KW Basin that, at the time of sludge retrieval, will contain an estimated volume of 5.2 m{sup 3} of KW Basin floor and pit sludge, 18.4 m{sup 3} of 105-K East (KE) Basin floor, pit, and canister sludge, and 3.5 m{sup 3} of settler tank sludge. The KE and KW Basin sludge consists of fuel corrosion products (including metallic uranium, and fission and activation products), small fuel fragments, iron and aluminum oxide, sand, dirt, operational debris, and biological debris. The settler tank sludge consists of sludge generated by the washing of KE and KW Basin fuel in the Primary Clean Machine. A detailed description of the origin of sludge and its chemical and physical characteristics can be found in HNF-41051, Preliminary STP Container and Settler Sludge Process System Description and Material Balance. In summary, the ECRTS retrieves sludge from the engineered containers and hydraulically transfers it as a slurry into an STSC positioned within a trailer-mounted STS cask located in a Modified KW Basin Annex. The slurry is allowed to settle within the STSC to concentrate the solids and clarify the supernate. After a prescribed settling period the supernate is decanted. The decanted supernate is filtered through a sand filter and returned to the basin. Subsequent batches of slurry are added to the STSC, settled, and excess supernate removed until the prescribed quantity of sludge is

Fiscal year 1993 1/25-scale sludge mobilization testing

International Nuclear Information System (INIS)

Powell, M.R.; Golcar, G.R.; Hymas, C.R.; McKay, R.L.

1995-04-01

Sixteen 1/25-scale sludge mobilization experiments were conducted in fiscal year (FY) 1993. The results of this testing are presented in this document. The ability of a single, centrally-located, scale model mixer pump to resuspend a layer of simulated tank sludge was evaluated for five different simulant types. The resistance of these simulants to the mobilizing action of the mixer pump jets was not found to adequately correlate with simulant vane shear strength. The data indicate that the simulant cohesion, as quantified by tensile strength, may provide a good measure of mobilization resistance. A single test was done to evaluate whether indexed mixer pump rotation is significantly more effective than the planned continuous oscillation. No significant difference was found in the sludge mobilization caused by these two modes of operation. Two tests were conducted using a clay-based sludge simulant that contained approximately 5 wt% soluble solids. The distance to which the mixer pump jets were effective for this simulant was approximately 50% greater than on similar simulants that did not contain soluble solids. The implication is that sludge dissolution effects may significantly enhance the performance of mixer pumps in some tanks. The development of a means to correlate the magnitude of this effect with waste properties is a direction for future work. Two tests were performed with the goal of determining whether the 1/25-scale sludge mobilization data can be scaled linearly to 1/12-scale. The two 1/25-scale tests were conducted using the same simulant recipe as had been used in previous 1/12-scale tests. The difficulty of matching the 1/25-scale simulants, with those used previously is thought to have adversely affected the results. Further tests are needed to determine whether the data from sludge mobilization tests can be linearly scaled

TECHNOLOGICAL AND ENVIRONMENTAL PROBLEMS CONNECTED WITH THERMAL CONVERSION OF SEWAGE SLUDGE

Directory of Open Access Journals (Sweden)

Alina Żogała

2016-02-01

Full Text Available Overview of the most common technological and environmental problems connected with thermal conversion of sewage sludge was presented in the article. Such issues as the influence of content of moisture and mineral matter on fuel properties of sludge, problem of emission of pollutants, problem of management of solid residue, risk of corrosion, were described. Besides, consolidated characteristic of the most important methods of thermal conversion of sewage sludge, with their advantages and disadvantages, was presented in the paper.

Biotechnology of intensive aerobic conversion of sewage sludge and food waste into fertilizer

Energy Technology Data Exchange (ETDEWEB)

Wang, J.-Y.; Stabnikova, O.; Show, K.-Y.; Ding, H.-B.; Tay, S.T.-L.; Ivanov, V.; Tay, J.-H.

2003-07-01

Biotechnology for intensive aerobic bioconversion of sewage sludge and food waste into fertilizer was developed. The wastes were treated in a closed reactor under controlled aeration, stirring, pH, and temperature at 60{sup o}C, after addition of starter bacterial culture Bacillus thermoamylovorans. The biodegradation of sewage sludge was studied by decrease of volatile solids (VS), content of organic carbon and autofluorescence of coenzyme F{sub 420}. The degradation of anaerobic biomass was faster than biodegradation of total organic matter. The best fertilizer was obtained when sewage sludge was thermally pre-treated, mixed with food waste, chalk, and artificial bulking agent. The content of volatile solid and the content of organic carbon decreased at 24.8% and 13.5% of total solids, respectively, during ten days of bioconversion. The fertilizer was a powder with moisture content of 5%. It was stable, and not toxic for the germination of plant seeds. Addition of 1.0 to 1.5% of this fertilizer to the subsoil increased the growth of different plants tested by 113 to 164 %. The biotechnology can be applied in larger scale for the recycling of sewage sludge and food wastes in Singapore. (author)

Harvesting biogas from wastewater sludge and food waste

International Nuclear Information System (INIS)

Chua, K H; Cheah, W L; Leong, Y P; Tan, C F

2013-01-01

Wastewater sludge and food waste are good source of biogas. Anaerobic treatment of slude and food waste able to produce biogas which is a potential renewable energy source. This study looks into the potential biogas generation and the effects of temperature on biogas generation. A lab scale reactor was used to simulate the biogas generation. The results show that wastewater sludge able to produced upto 44.82 ml biogas/kg of sludge. When mixed with food waste at a ratio of 30:70 (food waste), the biogas generated were 219.07 ml/kg of waste. Anaerobic of food waste alone produced biogas amount to 59.75 ml/kg of food waste. Anaerobic treatment also reduces the volume of waste. The effect of temperature shows that higher temperature produces more biogas than lower temperature.

Operational strategy, economic and environmental performance of sludge treatment reed bed systems - based on 28 years of experience

DEFF Research Database (Denmark)

Nielsen, S.; Larsen, Julie Dam

2016-01-01

Sludge treatment reed bed (STRB) systems have been used for dewatering and mineralisation of sludge in Europe since 1988. STRB systems provide substantial environmental, economic, and operational benefits compared to mechanical sludge dewatering solutions such as belt presses and centrifuges....... They require less energy, no chemicals, reduce the sludge volume and produce bio solids with dry solid contents up to 20-40% under Danish climate conditions, depending on the sludge quality. Experience has shown that sludge treated in STRBs represents a high quality product with a low content of pathogens...... compared to conventional mechanical dewatering devices, delivering an economic break-even of about 3-5 years. This paper provides an overview of the operation and maintenance costs and environmental benefits of a typical STRB based on the experiences gained from the operation of a large number of STRBs...

Effects of oxidation reduction potential in the bypass micro-aerobic sludge zone on sludge reduction for a modified oxic-settling-anaerobic process.

Science.gov (United States)

Li, Kexun; Wang, Yi; Zhang, Zhongpin; Liu, Dongfang

2014-01-01

Batch experiments were conducted to determine the effect of oxidation reduction potential (ORP) on sludge reduction in a bypass micro-aerobic sludge reduction system. The system was composed of a modified oxic-settling-anaerobic process with a sludge holding tank in the sludge recycle loop. The ORPs in the micro-aerobic tanks were set at approximately +350, -90, -150, -200 and -250 mV, by varying the length of aeration time for the tanks. The results show that lower ORP result in greater sludge volume reduction, and the sludge production was reduced by 60% at the lowest ORP. In addition, low ORP caused extracellular polymer substances dissociation and slightly reduced sludge activity. Comparing the sludge backflow characteristics of the micro-aerobic tank's ORP controlled at -250 mV with that of +350 mV, the average soluble chemical oxygen (SCOD), TN and TP increased by 7, 0.4 and 2 times, median particle diameter decreased by 8.5 μm and the specific oxygen uptake rate (SOUR) decreased by 0.0043 milligram O2 per gram suspended solids per minute. For the effluent, SCOD and TN and TP fluctuated around 30, 8.7 and 0.66 mg/L, respectively. Therefore, the effective assignment of ORP in the micro-aerobic tank can remarkably reduce sludge volume and does not affect final effluent quality.

Basic and Acidic Leaching of Sludge from Melton Valley Storage Tank W-25

Energy Technology Data Exchange (ETDEWEB)

Collins, J.L., Egan, B.Z., Beahm, E.C., Chase, C.W., Anderson, K.K.

1997-10-01

Bench-scale leaching tests were conducted with samples of tank waste sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation technology processes for use in concentrating the radionuclides and reducing the volume of waste for final disposal. This paper discusses the hot cell apparatus, the characterization of the sludge, the leaching methodology, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge at ambient temperature. Basic leaching tests were also conducted at 75 and 95 deg C. The major alpha-,gamma., and beta-emitting radionuclides in the centrifuged, wet sludge solids were {sup 137}Cs, {sup 60}Co, {sup 154}Eu, {sup 241}Am, {sup 244}Cm {sup 90}Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and anions were Na, Ca, Al, K, Mg, NO{sub 3}{sup -},CO{sub 3}{sup 2-}, OH{sup -}, and O{sup 2-} organic carbon content was 3.0 +/- 1.0%. The pH was 13. A surprising result was that about 93% of the {sup 137}Cs in the centrifuged, wet sludge solids was bound in the solids and could not be solubilized by basic leaching at ambient temperature and 75 deg C. However, the solubility of the {sup 137}Cs was enhanced by heating the sludge to 95 deg C. In one of the tests,about 42% of the {sup 137}Cs was removed by leaching with 6.3 M NaOH at 95 deg C.Removing {sup 137}Cs from the W-25 sludge with nitric acid was a slow process. About 13% of the {sup 137}Cs was removed in 16 h with 3.0 M HNO{sub 3}. Only 22% of the {sup 137}Cs was removed in 117 h usi 6.0 M HNO{sub 3}. Successive leaching of sludge solids with 0.5 M, 3.0 M, 3.0 M; and 6.0 M HNO{sub 3} for a total mixing time of 558 h removed 84% of the {sup 137}Cs. The use of caustic leaching prior to HNO{sub 3} leaching, and the use of HF with HNO{sub 3} in acidic leaching, increased the rate of {sup 137}Cs dissolution. Gel formation proved to be one of the biggest problems associated with HNO{sub 3

Basic and Acidic Leaching of Sludge from Melton Valley Storage Tank W-25

International Nuclear Information System (INIS)

Collins, J.L.; Egan, B.Z.; Beahm, E.C.; Chase, C.W.; Anderson, K.K.

1997-10-01

Bench-scale leaching tests were conducted with samples of tank waste sludge from the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to evaluate separation technology processes for use in concentrating the radionuclides and reducing the volume of waste for final disposal. This paper discusses the hot cell apparatus, the characterization of the sludge, the leaching methodology, and the results obtained from a variety of basic and acidic leaching tests of samples of sludge at ambient temperature. Basic leaching tests were also conducted at 75 and 95 deg C. The major alpha-,gamma., and beta-emitting radionuclides in the centrifuged, wet sludge solids were 137 Cs, 60 Co, 154 Eu, 241 Am, 244 Cm 90 Sr, Pu, U, and Th. The other major metals (in addition to the U and Th) and anions were Na, Ca, Al, K, Mg, NO 3 - ,CO 3 2- , OH - , and O 2- organic carbon content was 3.0 +/- 1.0%. The pH was 13. A surprising result was that about 93% of the 137 Cs in the centrifuged, wet sludge solids was bound in the solids and could not be solubilized by basic leaching at ambient temperature and 75 deg C. However, the solubility of the 137 Cs was enhanced by heating the sludge to 95 deg C. In one of the tests,about 42% of the 137 Cs was removed by leaching with 6.3 M NaOH at 95 deg C.Removing 137 Cs from the W-25 sludge with nitric acid was a slow process. About 13% of the 137 Cs was removed in 16 h with 3.0 M HNO 3 . Only 22% of the 137 Cs was removed in 117 h usi 6.0 M HNO 3 . Successive leaching of sludge solids with 0.5 M, 3.0 M, 3.0 M; and 6.0 M HNO 3 for a total mixing time of 558 h removed 84% of the 137 Cs. The use of caustic leaching prior to HNO 3 leaching, and the use of HF with HNO 3 in acidic leaching, increased the rate of 137 Cs dissolution. Gel formation proved to be one of the biggest problems associated with HNO 3 leaching of the W-25 sludge

Physical-Chemical Characterization of Solid Waste Generated in the Water Industry: Case Study of the Water Treatment Stations of the Metropolitan Region of Recife

Directory of Open Access Journals (Sweden)

Rosângela Gomes Tavares

2017-12-01

Full Text Available The objective of this research is to characterize the solid waste, commonly known as sludge, from the water treatment industry. Six main water treatment plants (Alto do Céu, Botafogo, Caixa d'água, Gurjaú, Suape and Tapacurá were selected from the Metropolitan Region of Recife, managed by Companhia Pernambucana de Saneamento. Nine samples were collected in the eleven month period in the discharge of the sludge from the decanters. These samples were characterized physico-chemically, based on the methodology of the Standard Methods for the Examination of Water and Wastewater (2012. The results indicated average humidity of 93%, average COD around 30 g/L and BOD of 4.5 g/L, indicating sludge of low biodegradability. The average values of total solids were 72 g/L, with 75% corresponding to fixed residues and 25% to volatiles. High concentrations of aluminum (1000 mg/L were observed, due to the use of aluminum sulphate as a coagulant, and iron, around 500 mg/L. This study assists the manager in the decision making of the sustainable management of the sludge, mainly in relation to the final disposal.

Corrosivity of cement pastes with addition of sludge generated in water treatment plant

International Nuclear Information System (INIS)

Rodrigues, R.A.; Martins, B.E.D.B.S.; Couto, V.M.P.; Carvalho, L.J.; Almeida, V.C.

2011-01-01

The amount of sludge produced in a water treatment plant (WTP) is an important economic factor in the context of waste treatment. The present article has the objective of study the corrosion of cement pastes produced with blended sludge. Aqueous extracts were produced from the milling of masses containing 5%, 10% and 30% of sludge in relation to cement after 28 days of healing. These extracts were used for polarization assays in order to determine the corrosiveness of the folders when in contact with the used fittings. Moreover, other chemical analysis tests were carried out for sludge characterization: X-ray fluorescence and X-ray diffraction. The obtained results point to the possibility of use of the studied cement masses in the development of construction materials promoting the economic reuse of WTP sludge before discarded in landfills. (author)

Separation of oil and grease from oil sludge using surfactant

International Nuclear Information System (INIS)

Ainon Abdul Aziz; Syed Hakimi Sakuma Syed Ahmad; Zalina Laili

2005-01-01

The objective of the experiments was to observe the efficiency of the surfactant to remove oil and grease from oil sludges using various surfactant concentration ranging from 10 %, 15 %, 20 % and 30 %. The surfactant solution consists of two mixtures of Aqua 2000 and D Bond. The oil sludge were subjected to heating and surfactant treatment process. Remaining oil and grease concentration were observed on the oil sludges after treatment. Small scale experiments were conducted by heating process, without heating process and heating process with addition of sodium chloride. Surfactant solution was added in each process. Results shows that there is separation of oil and grease from the oil sludges. There were formation of mini emulsions (oil in water). The higher the concentration of surfactant used, the higher the concentrations of mini emulsion formed as observed. Solid remains after the treatment process were found to contain lesser oil concentration with presence of bitumen, sediment, organic and inorganic materials. After a washing process using distilled water, the solid was still black but less oily than before the treatment. There is no separation of oil occurred in aqueous solution for the control experiment. (Author)

Digestion of thermally hydrolyzed sewage sludge by anaerobic sequencing batch reactor

International Nuclear Information System (INIS)

Wang Zhijun; Wang Wei; Zhang Xihui; Zhang Guangming

2009-01-01

Laboratory experiments were conducted to investigate the performance of an anaerobic sequencing batch reactor (ASBR) for the digestion of thermally hydrolyzed sewage sludge. Both mesophilic ASBR and continuous-flow stirred tank reactors (CSTR) were evaluated with an equivalent loading rate of 2.71 kg COD/m 3 day at 20-day hydraulic retention time (HRT) and 5.42 kg COD/m 3 day at 10-day HRT. The average total chemical oxygen demand (TCOD) removals of the ASBR at the 20-day and 10-day HRT were 67.71% and 61.66%, respectively. These were 12.38% and 27.92% higher than those obtained by CSTR. As a result, the average daily gas production of ASBR was 15% higher than that of the CSTR at 20-day HRT, and 31% higher than that of the CSTR at 10-day HRT. Solids in thermally hydrolyzed sludge accumulated within ASBR were able to reach a high steady state with solid content of 65-80 g/L. This resulted in a relatively high solid retention time (SRT) of 34-40 days in the ASBR at 10-day HRT. However, too much solid accumulation resulted in the unsteadiness of the ASBR, making regular discharge of digested sludge from the bottom of the ASBR necessary to keep the reactor stable. The evolution of the gas production, soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFAs) in an operation cycle of ASBR also showed that the ASBR was steady and feasible for the treatment of thermally hydrolyzed sludge

Pharmaceutical load in sewage sludge and biochar produced by hydrothermal carbonization.

Science.gov (United States)

vom Eyser, C; Palmu, K; Schmidt, T C; Tuerk, J

2015-12-15

We investigated the removal of twelve pharmaceuticals in sewage sludge by hydrothermal carbonization (HTC), which has emerged as a technology for improving the quality of organic waste materials producing a valuable biochar material. In this study, the HTC converted sewage sludge samples to a biochar product within 4h at a temperature of 210 °C and a resulting pressure of about 15 bar. Initial pharmaceutical load of the sewage sludge was investigated as well as the residual concentrations in biochar produced from spiked and eight native sewage sludge samples from three waste water treatment plants. Additionally, the solid contents of source material and product were compared, which showed a considerable increase of the solid content after filtration by HTC. All pharmaceuticals except sulfamethoxazole, which remained below the limit of quantification, frequently occurred in the investigated sewage sludges in the μg/kg dry matter (DM) range. Diclofenac, carbamazepine, metoprolol and propranolol were detected in all sludge samples with a maximum concentration of 800 μg/kgDM for metoprolol. HTC was investigated regarding its contaminant removal efficiency using spiked sewage sludge. Pharmaceutical concentrations were reduced for seven compounds by 39% (metoprolol) to≥97% (carbamazepine). In native biochar samples the four compounds phenazone, carbamazepine, metoprolol and propranolol were detected, which confirmed that the HTC process can reduce the load of micropollutants. In contrast to the other investigated compounds phenazone concentration increased, which was further addressed in thermal behaviour studies including three structurally similar potential precursors. Copyright © 2015 Elsevier B.V. All rights reserved.

COMPARISON BETWEEN DIFFERENT MODELS FOR RHEOLOGICAL CHARACTERIZATION OF ACTIVATED SLUDGE

Directory of Open Access Journals (Sweden)

A. H. Khalili Garakani

2011-09-01

Full Text Available Activated sludge flow rheology is a very complicated phenomenon. Studies related to activated sludge tend to classify sludge as non-Newtonian fluid. Until now, several theories have been built to describe the complex behavior of activated sludge with varying degrees of success. In this article, seven different models for viscosity of non-Newtonian fluids (i.e., Power law, Bingham plastic, Herschel-Bulkley, Casson, Sisko, Carreau and Cross were considered to evaluate their predictive capability of apparent viscosity of activated sludge. Results showed that although evaluating the constants in the four-parameter models is difficult, they provide the best prediction of viscosity in the whole range of shear rates for activated sludge. For easier prediction of viscosity at different mixed liquor suspended solids (2.74-31g/L, temperature (15-25°C and shear rate (1-1000/s, simple correlations were proposed. Comparing the results with the experimental data revealed that the proposed correlations are in good agreement with real apparent viscosities.

Treatment of urban sludge by hydrothermal carbonization.

Science.gov (United States)

Xu, Xiwei; Jiang, Enchen

2017-08-01

Urban sludge was treated by Hydrothermal carbonization (HTC). The effect of hydrothermal carbonization temperature, mixing with or without catalysts on solid products yield, heavy metal contents, turbidity and COD value was evaluated. The result showed solid products yield decreased from 92.04% to 52.65% when the temperature increased from 180 to 300°C. And the Cu, Zn, and Pb contents under exchangeable states decreased and reached discharge standard. Addition of FeCl 3 or Al(OH) 3 resulted in a significant increase in the exchangeable states of Zn, Pb, Cr, and Cd and decrease in their residual states. The turbidity and COD value of hydrothermal liquid decreased from 450° to 175°, and 13 to 6.8g/L, with increasing hydrothermal temperature. Comparison with HTC, solid productivity from low-temperature pyrolysis is higher. The exchangeable states of Cu, Zn, and Cr exceeded the limiting values. Our results show HTC can facilitate transforming urban sludge into no-pollution and energy-rich products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of solid retention time and nitrification capacity on the ability of activated sludge to remove pharmaceuticals

DEFF Research Database (Denmark)

Falås, Per; Andersen, Henrik Rasmus; Ledin, Anna

2012-01-01

Removal of five acidic pharmaceuticals (ibuprofen, ketoprofen, naproxen, diclofenac and clofibric acid) by activated sludge from five municipal activated sludge treatment processes, with various sludge ages and nitrification capacities, was assessed through batch experiments. The increase...... in aerobic sludge age from 1-3 to 7 days seemed to be critical for the removal of naproxen and ketoprofen, with markedly higher rates of removal at sludge ages of 7 days or more. No removal was shown for diclofenac and clofibric acid, while high rates were observed for ibuprofen in all investigated sludges...

Transire, a Program for Generating Solid-State Interface Structures

Science.gov (United States)

2017-09-14

ARL-TR-8134 ● SEP 2017 US Army Research Laboratory Transire, a Program for Generating Solid-State Interface Structures by...Program for Generating Solid-State Interface Structures by Caleb M Carlin and Berend C Rinderspacher Weapons and Materials Research Directorate, ARL...

Enhanced dewaterability of sludge during anaerobic digestion with thermal hydrolysis pretreatment: New insights through structure evolution.

Science.gov (United States)

Zhang, Jingsi; Li, Ning; Dai, Xiaohu; Tao, Wenquan; Jenkinson, Ian R; Li, Zhuo

2017-12-19

Comprehensive insights into the sludge digestate dewaterability were gained through porous network structure of sludge. We measured the evolution of digestate dewaterability, represented by the solid content of centrifugally dewatered cake, in high-solids sequencing batch digesters with and without thermal hydrolysis pretreatment (THP). The results show that the dewaterability of the sludge after digestion was improved by 3.5% (±0.5%) for unpretreated sludge and 5.1% (±0.4%) for thermally hydrolyzed sludge. Compared to the unpretreated sludge digestate, thermal hydrolysis pretreatment eventually resulted in an improvement of dewaterability by 4.6% (±0.5%). Smaller particle size and larger surface area of sludge were induced by thermal hydrolysis and anaerobic digestion treatments. The structure strength and compactness of sludge, represented by elastic modulus and fractal dimension respectively, decreased with increase of digestion time. The porous network structure was broken up by thermal hydrolysis pretreatment and was further weakened during anaerobic digestion, which correspondingly improved the dewaterability of digestates. The logarithm of elastic modulus increased linearly with fractal dimension regardless of the pretreatment. Both fractal dimension and elastic modulus showed linear relationship with dewaterability. The rheological characterization combined with the analysis of fractal dimension of sewage sludge porous network structure was found applicable in quantitative evaluation of sludge dewaterability, which depended positively on both thermal hydrolysis and anaerobic digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Use of hydrodynamic disintegration to accelerate anaerobic digestion of surplus activated sludge.

Science.gov (United States)

Grübel, Klaudiusz; Machnicka, Alicja

2009-12-01

Hydrodynamic disintegration of activated sludge resulted in organic matter and polymers transfer from the solid phase into the liquid phase. Disintegration by hydrodynamic cavitation had a positive effect on the degree and rate of excess sludge anaerobic digestion. Also, addition of a part of anaerobic digested sludge containing adapted microorganisms resulted in acceleration of the process. The disruption of cells of foam microorganisms and addition to the digestion process led to an increase of biogas production.

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

Science.gov (United States)

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

2014-01-01

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

Fate and distribution of pharmaceuticals in wastewater and sewage sludge of the conventional activated sludge (CAS) and advanced membrane bioreactor (MBR) treatment.

Science.gov (United States)

Radjenović, Jelena; Petrović, Mira; Barceló, Damià

2009-02-01

In this paper we report on the performances of full-scale conventional activated sludge (CAS) treatment and two pilot-scale membrane bioreactors (MBRs) in eliminating various pharmaceutically active compounds (PhACs) belonging to different therapeutic groups and with diverse physico-chemical properties. Both aqueous and solid phases were analysed for the presence of 31 pharmaceuticals included in the analytical method. The most ubiquitous contaminants in the sewage water were analgesics and anti-inflammatory drugs ibuprofen (14.6-31.3 microg/L) and acetaminophen (7.1-11.4 microg/L), antibiotic ofloxacin (0.89-31.7 microg/L), lipid regulators gemfibrozil (2.0-5.9 microg/L) and bezafibrate (1.9-29.8 microg/L), beta-blocker atenolol (0.84-2.8 microg/L), hypoglycaemic agent glibenclamide (0.12-15.9 microg/L) and a diuretic hydrochlorothiazide (2.3-4.8 microg/L). Also, several pharmaceuticals such as ibuprofen, ketoprofen, diclofenac, ofloxacin and azithromycin were detected in sewage sludge at concentrations up to 741.1, 336.3, 380.7, 454.7 and 299.6 ng/g dry weight. Two pilot-scale MBRs exhibited enhanced elimination of several pharmaceutical residues poorly removed by the CAS treatment (e.g., mefenamic acid, indomethacin, diclofenac, propyphenazone, pravastatin, gemfibrozil), whereas in some cases more stable operation of one of the MBR reactors at prolonged SRT proved to be detrimental for the elimination of some compounds (e.g., beta-blockers, ranitidine, famotidine, erythromycin). Moreover, the anti-epileptic drug carbamazepine and diuretic hydrochlorothiazide by-passed all three treatments investigated. Furthermore, sorption to sewage sludge in the MBRs as well as in the entire treatment line of a full-scale WWTP is discussed for the encountered analytes. Among the pharmaceuticals encountered in sewage sludge, sorption to sludge could be a relevant removal pathway only for several compounds (i.e., mefenamic acid, propranolol, and loratidine). Especially in the

Hydrogen production from paper sludge hydrolysate

NARCIS (Netherlands)

Kádár, Z.; Vrije, de G.J.; Budde, M.A.W.; Szengyel, Z.; Reczey, K.; Claassen, P.A.M.

2003-01-01

The main objective of this study was to develop a system for the production of 'renewable' hydrogen. Paper sludge is a solid industrial waste yielding mainly cellulose, which can be used, after hydrolysis, as a feedstock in anaerobic fermentation by (hyper)thermophilic organisms, such as Thermotoga

Recovery of energy and iron from oily sludge pyrolysis in a fluidized bed reactor.

Science.gov (United States)

Qin, Linbo; Han, Jun; He, Xiang; Zhan, Yiqiu; Yu, Fei

2015-05-01

In the steel industry, about 0.86 ton of oily sludge is produced for every 1000 tons of rolling steel. Due to the adverse impact on human health and the environment, oily sludge is designated as a hazardous waste in the Resource Conservation and Recovery Act (RCRT). In this paper, the pyrolysis treatment of oily sludge is studied in a fluidized bed reactor at a temperature range of 400-600 °C. During oily sludge pyrolysis, a maximum oil yield of 59.2% and a minimum energy loss of 19.0% are achieved at 500 °C. The energy consumption of treating 1 kg oily sludge is only 2.4-2.9 MJ. At the same time, the energy of produced oil, gas and solid residue are 20.8, 6.32, and 0.83 MJ, respectively. In particular, it is found that the solid residue contains more than 42% iron oxide, which can be used as the raw material for iron production. Thus, the simultaneous recovery of energy and iron from oil sludge by pyrolysis is feasible. Copyright © 2015 Elsevier Ltd. All rights reserved.

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).

Power generation from solid fuels

CERN Document Server

Spliethoff, Hartmut

2010-01-01

Power Generation from Solid Fuels introduces the different technologies to produce heat and power from solid fossil (hard coal, brown coal) and renewable (biomass, waste) fuels, such as combustion and gasification, steam power plants and combined cycles etc. The book discusses technologies with regard to their efficiency, emissions, operational behavior, residues and costs. Besides proven state of the art processes, the focus is on the potential of new technologies currently under development or demonstration. The main motivation of the book is to explain the technical possibilities for reduci

Sewage sludge disintegration by combined treatment of alkaline+high pressure homogenization.

Science.gov (United States)

Zhang, Yuxuan; Zhang, Panyue; Zhang, Guangming; Ma, Weifang; Wu, Hao; Ma, Boqiang

2012-11-01

Alkaline pretreatment combined with high pressure homogenization (HPH) was applied to promote sewage sludge disintegration. For sewage sludge with a total solid content of 1.82%, sludge disintegration degree (DD(COD)) with combined treatment was higher than the sum of DD(COD) with single alkaline and single HPH treatment. NaOH dosage ⩽0.04mol/L, homogenization pressure ⩽60MPa and a single homogenization cycle were the suitable conditions for combined sludge treatment. The combined sludge treatment showed a maximum DD(COD) of 59.26%. By regression analysis, the combined sludge disintegration model was established as 11-DD(COD)=0.713C(0.334)P(0.234)N(0.119), showing that the effect of operating parameters on sludge disintegration followed the order: NaOH dosage>homogenization pressure>number of homogenization cycle. The energy efficiency with combined sludge treatment significantly increased compared with that with single HPH treatment, and the high energy efficiency was achieved at low homogenization pressure with a single homogenization cycle. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

The dissolution of metal decontamination sludges stored in tanks and their management

Energy Technology Data Exchange (ETDEWEB)

Prokopowicz, R.A.; Phillips, B. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2011-07-01

The decontamination of stainless steel components is accomplished by the use of alkaline permanganate solutions, followed by an application of solutions of complexing agents such as citric acid or oxalic acid. Spent decontamination solutions comprising residues from both steps were combined in several waste storage tanks, where they have been in storage for several years. In those tanks, a reaction between residual permanganate and unreacted complexing agents produced sludges, consisting mainly of manganese dioxide, that reside in the tanks along with supernatant liquid. In a campaign that was conducted a few years ago, the accumulated waste solution was partially treated and disposed. This treatment consisted of decanting only the supernatant liquid and transporting it to a liquid waste treatment facility that employed a Thin Film Evaporator (TFE) to concentrate the liquid and ultimately produce a bitumen-encapsulated solidified waste form for storage. A study of treatment options for the remaining sludge is reported here. The requirement was to determine a simple means of treating the sludge using existing routine processes and equipment. This will be a significant step toward the decommissioning of the decontamination waste storage tanks. The available equipment at the liquid waste treatment facility was not designed to process sludge or slurries containing a large volume fraction of solids. Laboratory testing was carried out to find a means of dissolving the decontamination waste sludges, preferably in situ, and filtering undissolved solids to meet the feed requirements of the TFE in the liquid waste treatment facility. A concentrated citric acid solution was applied to sludge samples, without the use of externally applied mixing of the reagent and sludge. In all of the samples of actual decontamination waste sludge that were tested, a quantity of undissolved material remained after treatment with citric acid. The quantities were relatively small in volume, and

The dissolution of metal decontamination sludges stored in tanks and their management

International Nuclear Information System (INIS)

Prokopowicz, R.A.; Phillips, B.

2011-01-01

The decontamination of stainless steel components is accomplished by the use of alkaline permanganate solutions, followed by an application of solutions of complexing agents such as citric acid or oxalic acid. Spent decontamination solutions comprising residues from both steps were combined in several waste storage tanks, where they have been in storage for several years. In those tanks, a reaction between residual permanganate and unreacted complexing agents produced sludges, consisting mainly of manganese dioxide, that reside in the tanks along with supernatant liquid. In a campaign that was conducted a few years ago, the accumulated waste solution was partially treated and disposed. This treatment consisted of decanting only the supernatant liquid and transporting it to a liquid waste treatment facility that employed a Thin Film Evaporator (TFE) to concentrate the liquid and ultimately produce a bitumen-encapsulated solidified waste form for storage. A study of treatment options for the remaining sludge is reported here. The requirement was to determine a simple means of treating the sludge using existing routine processes and equipment. This will be a significant step toward the decommissioning of the decontamination waste storage tanks. The available equipment at the liquid waste treatment facility was not designed to process sludge or slurries containing a large volume fraction of solids. Laboratory testing was carried out to find a means of dissolving the decontamination waste sludges, preferably in situ, and filtering undissolved solids to meet the feed requirements of the TFE in the liquid waste treatment facility. A concentrated citric acid solution was applied to sludge samples, without the use of externally applied mixing of the reagent and sludge. In all of the samples of actual decontamination waste sludge that were tested, a quantity of undissolved material remained after treatment with citric acid. The quantities were relatively small in volume, and

A study on the dewatering of industrial waste sludge by fry-drying technology

International Nuclear Information System (INIS)

Ohm, Tae-In; Chae, Jong-Seong; Kim, Jeong-Eun; Kim, Hee-kyum; Moon, Seung-Hyun

2009-01-01

In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge. Many methods have been applied, including direct and indirect heat drying, but these approaches of reducing water content to below 40% after drying is very inefficient in energy utilization of drying sludge. In this study, fry-drying technology with a high heat transfer coefficient of approximately 500 W/m 2 deg. C was used to dry industrial wastewater sludge. Also waste oil was used in the fry-drying process, and because the oil's boiling point is between 240 and 340 deg. C and the specific heat is approximately 60% of that of water. In the fry-drying system, the sludge is input by molding it into a designated form after heating the waste oil at temperatures between 120 and 170 deg. C. At these temperatures, the heated oil rapidly evaporates the water contained in the sludge, leaving the oil itself. After approximately 10 min, the water content of the sludge was less than 10%, and its heating value surpassed 5300 kcal/kg. Indeed, this makes the organic sludge appropriate for use as a solid fuel. The wastewater sludge used in this study was the designated waste discharged from chemical, leather and plating plants. These samples varied in characteristics, especially with regard to heavy metal concentration. After drying the three kinds of wastewater sludge at oil temperatures 160 deg. C for 10 min, it was found that the water content in the sludge from the chemical, leather, and plating plants reduced from 80.0 to 5.5%, 81.6 to 1.0%, and 65.4 to 0.8%, respectively. Furthermore, the heat values of the sludge from the chemical, leather, and plating plants prior to fry-drying were 217, 264, and 428 kcal/kg, respectively. After drying, these values of sludge increased to 5317, 5983 and 6031 kcal/kg, respectively. The heavy metals detected in the sludge after drying were aluminum

Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

International Nuclear Information System (INIS)

STALLINGS, MARY

2004-01-01

This report presents findings from tests investigating the dissolution of simulated and radioactive Savannah River Site sludges with 4 per cent oxalic acid and mixtures of oxalic and citric acid previously recommended by a Russian team from the Khlopin Radium Institute and the Mining and Chemical Combine (MCC). Testing also included characterization of the simulated and radioactive waste sludges. Testing results showed the following: Dissolution of simulated HM and PUREX sludges with oxalic and citric acid mixtures at SRTC confirmed general trends reported previously by Russian testing. Unlike the previous Russian testing six sequential contacts of a mixture of oxalic acid citric acids at a 2:1 ratio (v/w) of acid to sludge did not produce complete dissolution of simulated HM and PUREX sludges. We observed that increased sludge dissolution occurred at a higher acid to sludge ratio, 50:1 (v/w), compared to the recommended ratio of 2:1 (v/w). We observed much lower dissolution of aluminum in a simulated HM sludge by sodium hydroxide leaching. We attribute the low aluminum dissolution in caustic to the high fraction of boehmite present in the simulated sludge. Dissolution of HLW sludges with 4 per cent oxalic acid and oxalic/citric acid followed general trends observed with simulated sludges. The limited testing suggests that a mixture of oxalic and citric acids is more efficient for dissolving HM and PUREX sludges and provides a more homogeneous dissolution of HM sludge than oxalic acid alone. Dissolution of HLW sludges in oxalic and oxalic/citric acid mixtures produced residual sludge solids that measured at higher neutron poison to equivalent 235U weight ratios than that in the untreated sludge solids. This finding suggests that residual solids do not present an increased nuclear criticality safety risk. Generally the neutron poison to equivalent 235U weight ratios of the acid solutions containing dissolved sludge components are lower than those in the untreated

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.

Hydrogen sulfide formation control and microbial competition in batch anaerobic digestion of slaughterhouse wastewater sludge: Effect of initial sludge pH.

Science.gov (United States)

Yan, Li; Ye, Jie; Zhang, Panyue; Xu, Dong; Wu, Yan; Liu, Jianbo; Zhang, Haibo; Fang, Wei; Wang, Bei; Zeng, Guangming

2018-07-01

High sulfur content in excess sludge impacts the production of biomethane during anaerobic digestion, meanwhile leads to hydrogen sulfide (H 2 S) formation in biogas. Effect of initial sludge pH on H 2 S formation during batch mesophilic anaerobic digestion of slaughterhouse wastewater sludge was studied in this paper. The results demonstrated that when the initial sludge pH increased from 6.5 to 8.0, the biogas production increased by 10.1%, the methane production increased by 64.1%, while the H 2 S content in biogas decreased by 44.7%. The higher initial sludge pH inhibited the competition of sulfate-reducing bacteria with methane-producing bacteria, and thus benefitted the growth of methanogens. Positive correlation was found between the relative abundance of Desulfomicrobium and H 2 S production, as well as the relative abundance of Methanosarcina and methane production. More sulfates and organic sulfur were transferred to solid and liquid rather than H 2 S formation at a high initial pH. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evaluation of physical stability and leachability of Portland Pozzolona Cement (PPC) solidified chemical sludge generated from textile wastewater treatment plants

International Nuclear Information System (INIS)

Patel, Hema; Pandey, Suneel

2012-01-01

Highlights: ► Stabilization/solidification of chemical sludge from textile wastewater treatment plants using Portland Pozzolona Cement (PPC) containing fly ash. ► Physical engineering (compressive strength and block density) indicates that sludge has potential to be reused for construction purpose after stabilization/solidification. ► Leaching of heavy metals from stabilized/solidified materials were within stipulated limits. ► There is a modification of microstructural properties of PPC with sludge addition as indicated by XRD and SEM patterns. - Abstract: The chemical sludge generated from the treatment of textile dyeing wastewater is a hazardous waste as per Indian Hazardous Waste Management rules. In this paper, stabilization/solidification of chemical sludge was carried out to explore its reuse potential in the construction materials. Portland Pozzolona Cement (PPC) was selected as the binder system which is commercially available cement with 10–25% fly ash interground in it. The stabilized/solidified blocks were evaluated in terms of unconfined compressive strength, block density and leaching of heavy metals. The compressive strength (3.62–33.62 MPa) and block density (1222.17–1688.72 kg/m 3 ) values as well as the negligible leaching of heavy metals from the stabilized/solidified blocks indicate that there is a potential of its use for structural and non-structural applications.

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.

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

Science.gov (United States)

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

2018-04-01

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

Water washes and caustic leaches of sludge from Hanford Tank S-101 and water washes of sludge from Hanford Tank C-103

International Nuclear Information System (INIS)

Hunt, R.D.; Collins, J.L.; Chase, C.W.

1998-07-01

In 1993, the Department of Energy (DOE) selected the enhanced sludge washing (ESW) process as the baseline for pretreatment of Hanford tank sludges. The ESW process uses a series of water washes and caustic leaches to separate nonradioactive components such as aluminum, chromium, and phosphate from the high-level waste sludges. If the ESW process is successful, the volume of immobilized high-level waste will be significantly reduced. The tests on the sludge from Hanford Tank S-101 focused on the effects of process variables such as sodium hydroxide concentration (1 and 3 M), temperature (70 and 95 C), and leaching time (5, 24, 72, and 168 h) on the efficacy of the ESW process with realistic liquid-to-solid ratios. Another goal of this study was to evaluate the effectiveness of water washes on a sludge sample from hanford Tank C-103. The final objective of this study was to test potential process control monitors during the water washes and caustic leaches with actual sludge. Both 137 Cs activity and conductance were measured for each of the water washes and caustic leaches. Experimental procedures, a discussion of results, conclusions and recommendations are included in this report

Pressurised electro-osmotic dewatering of activated and anaerobically digested sludges: electrical variables analysis.

Science.gov (United States)

Citeau, M; Olivier, J; Mahmoud, A; Vaxelaire, J; Larue, O; Vorobiev, E

2012-09-15

Pressurised electro-osmotic dewatering (PEOD) of two sewage sludges (activated and anaerobically digested) was studied under constant electric current (C.C.) and constant voltage (C.V.) with a laboratory chamber simulating closely an industrial filter. The influence of sludge characteristics, process parameters, and electrode/filter cloth position was investigated. The next parameters were tested: 40 and 80 A/m², 20, 30, and 50 V-for digested sludge dewatering; and 20, 40 and 80 A/m², 20, 30, and 50 V-for activated sludge dewatering. Effects of filter cloth electric resistance and initial cake thickness were also investigated. The application of PEOD provides a gain of 12 points of dry solids content for the digested sludge (47.0% w/w) and for the activated sludge (31.7% w/w). In PEOD processed at C.C. or at C.V., the dewatering flow rate was similar for the same electric field intensity. In C.C. mode, both the electric resistance of cake and voltage increase, causing a temperature rise by ohmic effect. In C.V. mode, a current intensity peak was observed in the earlier dewatering period. Applying at first a constant current and later on a constant voltage, permitted to have better control of ohmic heating effect. The dewatering rate was not significantly affected by the presence of filter cloth on electrodes, but the use of a thin filter cloth reduced remarkably the energy consumption compared to a thicker one: 69% of reduction energy input at 45% w/w of dry solids content. The reduction of the initial cake thickness is advantageous to increase the final dry solids content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ozonation of return activated sludge for disintegration and solubilisation with synthesized titanium oxide as catalyst

Science.gov (United States)

Sarif, S. F. Z. Mohd; Alias, S. S.; Ridwan, F. Muhammad; Salim, K. S. Ku; Abidin, C. Z. A.; Ali, U. F. Md.

2018-03-01

Ozonation of activated sludge in the present of titanium dioxide (TiO2) as catalyst to enhance the production of hydroxyl radical was evaluated in comparison to the sole ozonation process. In this process, the catalytic ozontion showed improvement in increasing ozone consumption and improving activated sludge disintegration and solubilisation. The reduction of total suspended solid (TSS), volatile suspended solid (VSS) and soluble chemical oxygen demand (SCOD) solubilisation was better in the catalytic ozonation system. Initial pH 7 of activated sludge was found best to disintegrate and solubilise the sludge flocs. However upon additional of sodium hydroxide (NaOH) in pH adjustment enhanced the solubilisation of organic matter from the flocs and cells, making the initial pH 9 is the best condition for activated sludge solubilisation. Yet the initial pH 7 of activated sludge supernatant was the best condition to achieve SCOD solubilisation due to sludge floc disintegration, when it had stronger correlation between TSS reduction and SCOD solubilisation (R2=0.961). Lower amount of catalyst of 100 mgTiO2/gTSS was found to disintegrate and solubilise the activated sludge better with 30.4% TSS reduction and 25.2% SCOD solubilisation efficiency, compared to 200 mgTiO2/gTSS with 21.9% and 17.1% TSS reduction and SCOD solubilisation, respectively.

Effect of thermal pretreatment on the biogas production and microbial communities balance during anaerobic digestion of urban and industrial waste activated sludge.

Science.gov (United States)

Ennouri, Hajer; Miladi, Baligh; Diaz, Soraya Zahedi; Güelfo, Luis Alberto Fernández; Solera, Rosario; Hamdi, Moktar; Bouallagui, Hassib

2016-08-01

The effect of thermal pre-treatment on the microbial populations balance and biogas production was studied during anaerobic digestion of waste activated sludge (WAS) coming from urban (US: urban sludge) and industrial (IS: industrial sludge) wastewater treatment plants (WWTP). The highest biogas yields of 0.42l/gvolatile solid (VS) removed and 0.37l/gVS removed were obtained with urban and industrial sludge pre-treated at 120°C, respectively. Fluorescent in situ hybridization (FISH) was used to quantify the major Bacteria and Archaea groups. Compared to control trails without pretreatment, Archaea content increased from 34% to 86% and from 46% to 83% for pretreated IS and US, respectively. In fact, the thermal pre-treatment of WAS enhanced the growth of hydrogen-using methanogens (HUMs), which consume rapidly the H2 generated to allow the acetogenesis. Therefore, the stable and better performance of digesters was observed involving the balance and syntrophic associations between the different microbial populations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intrinsic kinetic parameters of substrate utilization by immobilized anaerobic sludge.

Science.gov (United States)

Zaiat, M; Vieira, L G; Foresti, E

1997-01-20

This article presents a method for evaluating the intrinsic kinetic parameters of the specific substrate utilization rate (r) equation and discusses the results obtained for anaerobic sludge-bed samples taken from a horizontal-flow anaerobic immobilized sludge (HAIS) reactor. This method utilizes a differential reactor filled with polyurethane foam matrices containing immobilized anaerobic sludge which is subjected to a range of feeding substrate flow rates. The range of liquid superficial velocities thus obtained are used for generating data of observed specific substrate utilization rates (r(obs)) under a diversity of external mass transfer resistance conditions. The r(obs) curves are then adjusted to permit their extrapolation for the condition of no external mass transfer resistance, and the values determined are used as a test for the condition of absence of limitation of internal mass transfer. The intrinsic parameters r(max), the maximum specific substrate utilization rate, and K(s), the half-velocity coefficient, are evaluated from the r values under no external mass transfer resistance and no internal mass transfer limitation. The application of such a method for anaerobic sludge immobilized in polyurethane foam particles treating a glucose substrate at 30 degrees C resulted in intrinsic r(max) and K(s), respectively, of 0.330 mg chemical oxygen demand (COD) . mg(-1) volatile suspended solids (VSS) . h(-1) and 72 mg COD . L(-1). In comparison with the values found in the literature, intrinsic r(max) is significantly high and intrinsic K(s) is relatively low. (c) 1997 John Wiley & Sons, Inc.

Sludge busters

Energy Technology Data Exchange (ETDEWEB)

Pichon, Max

2010-07-15

Woolgoolga couldn't handle its sludge load as the sludge ponds fill up. And there is nowhere to take it, so they have to take it to landfill. That is a very expensive way of dealing with it,” said McKibbin. It was also a growing problem, with Coffs Harbour Water budgeting $1.5 million to augment the sludge management system, including a third pond and centrifuge.But having observed the For Earth system at the Macksville Sewage Treatment plant in Nambucca, the council water authority instead opted for a 12-month trial of the system, which started last August. The aeration system was installed and some four litres a day of probiotics has been added to the 16kL sludge lagoons since then. Coffs Harbour Water's Adam Wilson is pleased with the results to date. The volume of sludge coming out of the ponds has plunged 47 per cent compared to the same period last year, solids concentration has dropped 61 per cent and the sludge dries in 10 days rather than 3-4 weeks.There are still the coldest winter months to go, but McKibbin said that presents no problems. “What happens is the cooler water temperatures will slow down the bacteria activity. But that's the beauty of adding probiotics bacteria, you can up the numbers and by doing that you're not held back by water temperature,” he said. After the initial set up cost of $22,000 and the $150 a week in probiotics, the sludge management operating costs have reduced by $1,416 per week, paying for the system in just 15 weeks. Operator time has been cut from 10 hours per week to two hours, but the biggest saving is more than halving the $3,000 a week bill to dispose of the dried sludge. Little wonder Coffs Harbour Water has already extended the use of probiotics and low energy aeration to three other water reclamation plants, though it stopped short of applying the technology to the Karangi Water Treatment Plant due to high concentrations of chemicals and the low biological content of its sludge. More information at www.forearth.com.au.

Sludge busters

International Nuclear Information System (INIS)

Pichon, Max

2010-01-01

Woolgoolga couldn't handle its sludge load as the sludge ponds fill up. And there is nowhere to take it, so they have to take it to landfill. That is a very expensive way of dealing with it,” said McKibbin. It was also a growing problem, with Coffs Harbour Water budgeting $1.5 million to augment the sludge management system, including a third pond and centrifuge.But having observed the For Earth system at the Macksville Sewage Treatment plant in Nambucca, the council water authority instead opted for a 12-month trial of the system, which started last August. The aeration system was installed and some four litres a day of probiotics has been added to the 16kL sludge lagoons since then. Coffs Harbour Water's Adam Wilson is pleased with the results to date. The volume of sludge coming out of the ponds has plunged 47 per cent compared to the same period last year, solids concentration has dropped 61 per cent and the sludge dries in 10 days rather than 3-4 weeks.There are still the coldest winter months to go, but McKibbin said that presents no problems. “What happens is the cooler water temperatures will slow down the bacteria activity. But that's the beauty of adding probiotics bacteria, you can up the numbers and by doing that you're not held back by water temperature,” he said. After the initial set up cost of $22,000 and the $150 a week in probiotics, the sludge management operating costs have reduced by $1,416 per week, paying for the system in just 15 weeks. Operator time has been cut from 10 hours per week to two hours, but the biggest saving is more than halving the $3,000 a week bill to dispose of the dried sludge. Little wonder Coffs Harbour Water has already extended the use of probiotics and low energy aeration to three other water reclamation plants, though it stopped short of applying the technology to the Karangi Water Treatment Plant due to high concentrations of chemicals and the low biological content of its sludge. More information at www.forearth.com.au

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)

NEW SOLID FUELS FROM COAL AND BIOMASS WASTE; FINAL

International Nuclear Information System (INIS)

Hamid Farzan

2001-01-01

fuel. These fuels will be converted to energy while reducing CO(sub 2) emissions from power generating boilers and mitigating global warming concerns. This report describes the sludge analysis, solid fuel preparation and production, combustion performance, environmental emissions and required equipment

SEISMIC DESIGN REQUIREMENTS SELECTION METHODOLOGY FOR THE SLUDGE TREATMENT and M-91 SOLID WASTE PROCESSING FACILITIES PROJECTS

International Nuclear Information System (INIS)

RYAN GW

2008-01-01

In complying with direction from the U.S. Department of Energy (DOE), Richland Operations Office (RL) (07-KBC-0055, 'Direction Associated with Implementation of DOE-STD-1189 for the Sludge Treatment Project,' and 08-SED-0063, 'RL Action on the Safety Design Strategy (SDS) for Obtaining Additional Solid Waste Processing Capabilities (M-91 Project) and Use of Draft DOE-STD-I 189-YR'), it has been determined that the seismic design requirements currently in the Project Hanford Management Contract (PHMC) will be modified by DOE-STD-1189, Integration of Safety into the Design Process (March 2007 draft), for these two key PHMC projects. Seismic design requirements for other PHMC facilities and projects will remain unchanged. Considering the current early Critical Decision (CD) phases of both the Sludge Treatment Project (STP) and the Solid Waste Processing Facilities (M-91) Project and a strong intent to avoid potentially costly re-work of both engineering and nuclear safety analyses, this document describes how Fluor Hanford, Inc. (FH) will maintain compliance with the PHMC by considering both the current seismic standards referenced by DOE 0 420.1 B, Facility Safety, and draft DOE-STD-1189 (i.e., ASCE/SEI 43-05, Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities, and ANSI ANS 2.26-2004, Categorization of Nuclear Facility Structures, Systems and Components for Seismic Design, as modified by draft DOE-STD-1189) to choose the criteria that will result in the most conservative seismic design categorization and engineering design. Following the process described in this document will result in a conservative seismic design categorization and design products. This approach is expected to resolve discrepancies between the existing and new requirements and reduce the risk that project designs and analyses will require revision when the draft DOE-STD-1189 is finalized

The exploitation of sludge from aggregate plants in the manufacture of porous fired clay bricks

Directory of Open Access Journals (Sweden)

Chamorro-Trenado, M. A.

2016-09-01

Full Text Available Aggregates (gravel and sand are, after water, the Earth’s second most used natural resource, representing about 50% of all consumed mineral resources. Aggregate production generates a large quantity of waste from the aggregate washing process. This waste is made up of suspended solids – sludge – which has a great environmental impact. It is deposited in huge troughs because of the impossibility of discharging it directly into rivers. Many plants have incorporated decanters and filter presses to separate the solid from the liquid fraction. This paper evaluates the possibility of exploiting the solid fraction (i.e. sludge in the manufacture of fired clay bricks. The added value of these bricks is, on the one hand, the exploitation of sludge as a currently useless waste product, and on the other, the use of this sludge to enhance the physical and mechanical properties of conventional fired clay bricks.Los áridos son la segunda materia prima más consumida en la Tierra después del agua, representando alrededor del 50% de todos los recursos minerales consumidos. El proceso de elaboración de estos áridos genera una gran cantidad de residuos procedentes de su lavado. Se trata de partículas sólidas en suspensión – lodos – de gran impacto ambiental, que se depositan en grandes charcas ante la imposibilidad de verterlos directamente al rio. Muchas empresas han incorporado decantadores y filtros de prensa para separar la fracción solida de la líquida. El presente trabajo evalúa la posibilidad de utilizar la fracción sólida, es decir el barro, para la fabricación de piezas cerámicas. El valor añadido de estas piezas es por un lado el aprovechamiento del barro como producto residual, que en estos momentos es desechable, y por otro, conseguir que este barro mejore las propiedades físico-mecánicas de la cerámica convencional.

A low sludge generated anode by hybrid solar electrocoagulation for the removal of lead

Science.gov (United States)

Hussin, F.; Aroua, M. K.

2017-06-01

In this work, perforated zinc is proposed as a new anode for lead removal by hybrid solar electrocoagulation. The characteristics of the sludge were investigated to understand the behaviour of lead removal during electrocoagulation. Sludge products formed were characterised using X-ray diffraction (XRD), X-ray fluorescence (XRF) and Field Emission Scanning Electron Microscopy (FESEM). In addition, the pH variation during electrocoagulation and effects on the sludge products were examined. At optimum conditions showed that the perforated zinc electrode produced better performance with high removal efficiency, low sludge volume index and less energy consumption.

SLUDGE RETRIEVAL FROM HANFORD K WEST BASIN SETTLER TANKS

International Nuclear Information System (INIS)

Erpenbeck, E.G.; Leshikar, G.A.

2011-01-01

In 2010, an innovative, remotely operated retrieval system was deployed to successfully retrieve over 99.7% of the radioactive sludge from ten submerged tanks in Hanford's K-West Basin. As part of K-West Basin cleanup, the accumulated sludge needed to be removed from the 0.5 meter diameter by 5 meter long settler tanks and transferred approximately 45 meters to an underwater container for sampling and waste treatment. The abrasive, dense, non-homogeneous sludge was the product of the washing process of corroded nuclear fuel. It consists of small (less than 600 micron) particles of uranium metal, uranium oxide, and various other constituents, potentially agglomerated or cohesive after 10 years of storage. The Settler Tank Retrieval System (STRS) was developed to access, mobilize and pump out the sludge from each tank using a standardized process of retrieval head insertion, periodic high pressure water spray, retraction, and continuous pumping of the sludge. Blind operations were guided by monitoring flow rate, radiation levels in the sludge stream, and solids concentration. The technology developed and employed in the STRS can potentially be adapted to similar problematic waste tanks or pipes that must be remotely accessed to achieve mobilization and retrieval of the sludge within.

Urban solid waste in the production of Lafoensia pacari seedlings

Directory of Open Access Journals (Sweden)

Alan H. M. de Abreu

Full Text Available ABSTRACT This study aimed to verify the potential of urban solid wastes as substrate for production of seedlings of Lafoensia pacari. Five treatments were tested, four with solid wastes and one standard substrate, namely: sewage sludge from Alegria Wastewater Treatment Plant (WTP; sewage sludge from Ilha do Governador WTP; sewage sludge from Sarapuí WTP; domestic garbage compost (Fertlurb; and a commercial substrate made of biostabilized pine bark (standard substrate. The wastes received 20% (in volume of shredded coconut fiber. At 105 days after sowing, the seedlings were evaluated for different quality parameters. Seedlings produced with Sarapuí WTP sewage sludge showed the best results in all the parameters, followed by seedlings produced with sewage sludge from Alegria and Ilha do Governador WTPs, which did not differ. Seedlings produced with domestic garbage compost showed satisfactory results, higher than the ones observed for seedlings produced with commercial substrate. The urban solid wastes with 20% of coconut fiber showed high potential and can be recommended for the composition of substrate in the production of Lafoensia pacari seedlings.

Municipal solid waste generation in Kathmandu, Nepal.

Science.gov (United States)

Dangi, Mohan B; Pretz, Christopher R; Urynowicz, Michael A; Gerow, Kenneth G; Reddy, J M

2011-01-01

Waste stream characteristics must be understood to tackle waste management problems in Kathmandu Metropolitan City (KMC), Nepal. Three-stage stratified cluster sampling was used to evaluate solid waste data collected from 336 households in KMC. This information was combined with data collected regarding waste from restaurants, hotels, schools and streets. The study found that 497.3 g capita(-1) day(-1) of solid waste was generated from households and 48.5, 113.3 and 26.1 kg facility(-1) day(-1) of waste was generated from restaurants, hotels and schools, respectively. Street litter measured 69.3 metric tons day(-1). The average municipal solid waste generation rate was 523.8 metric tons day(-1) or 0.66 kg capita(-1) day(-1) as compared to the 320 metric tons day(-1) reported by the city. The coefficient of correlation between the number of people and the amount of waste produced was 0.94. Key household waste constituents included 71% organic wastes, 12% plastics, 7.5% paper and paper products, 5% dirt and construction debris and 1% hazardous wastes. Although the waste composition varied depending on the source, the composition analysis of waste from restaurants, hotels, schools and streets showed a high percentage of organic wastes. These numbers suggest a greater potential for recovery of organic wastes via composting and there is an opportunity for recycling. Because there is no previous inquiry of this scale in reporting comprehensive municipal solid waste generation in Nepal, this study can be treated as a baseline for other Nepalese municipalities. Copyright © 2010 Elsevier Ltd. All rights reserved.

Water Utility Lime Sludge Reuse – An Environmental Sorbent ...

Science.gov (United States)

Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up included a simulated flue gas preparation unit, a lab-scale wet scrubber, and a mercury analyzer system. The influent mercury concentration was based on a range from 22 surveyed power plants. The reactivity of the lime sludge sample for acid neutralization was determined using a method similar to method ASTM C1318-95. Similar experiments were conducted using reagent calcium carbonate and calcium sulfate to obtain baseline data for comparing with the lime sludge test results. The project also evaluated the techno-economic feasibility and sustainable benefits of reusing lime softening sludge. If implemented on a large scale, this transformative approach for recycling waste materials from water treatment utilities at power generation utilities for environmental cleanup can save both water and power utilities millions of dollars. Huge amounts of lime sludge waste, generated from hundreds of water treatment utilities across the U.S., is currently disposed in landfills. This project evaluated a sustainable and economically-attractive approach to the use of lime sludge waste as a valuable resource for power generation utilities.

Reduction of heavy metals in refinery waste sludge using em treatment

International Nuclear Information System (INIS)

Ahmad, J.; Ahmad, F.; Saleemi, A.R.; Ahmad, I.

2005-01-01

This paper presents the efforts of National Cleaner Production Center (NCPC) and Attock Refinery Limited (ARL) Rawalpindi, to address the problem of refinery solid waste. A trial project was designed to treat and convert 1.7 m ton to oil sludge into environmental friendly residue (compost) under anaerobic conditions. The residue can be treated as bio fertilizer for agricultural purpose. The trial on bio remediation (anaerobic) of oily sludge of ARL, Rawalpindi within its premises using EM technology was successfully completed with the collaboration of effective microorganism research organization (EMRO), NCPC and ARL between 29th October to 10th December, 2002. The effective microorganisms transformed the undiluted oily sludge from ARL into bioactive sludge; which may be called as bio sludge. For heavy metal breakdown the trial data shows that Ba has been reduced by 85% in the EM. Treated oily sludge as compared to original ARL sludge, and Pb, Fe, Zn and Ni have been reduced by about 50% in the treated bio sludge. The contents of As, Cr, Cu and Mn showed no change. The residue obtained can be used as a bio fertilizer. (author)

Immobilization of metal-humic acid complexes in anaerobic granular sludge for their application as solid-phase redox mediators in the biotransformation of iopromide in UASB reactors.

Science.gov (United States)

Cruz-Zavala, Aracely S; Pat-Espadas, Aurora M; Rangel-Mendez, J Rene; Chazaro-Ruiz, Luis F; Ascacio-Valdes, Juan A; Aguilar, Cristobal N; Cervantes, Francisco J

2016-05-01

Metal-humic acid complexes were synthesized and immobilized by a granulation process in anaerobic sludge for their application as solid-phase redox mediators (RM) in the biotransformation of iopromide. Characterization of Ca- and Fe-humic acid complexes revealed electron accepting capacities of 0.472 and 0.556milli-equivalentsg(-1), respectively. Once immobilized, metal-humic acid complexes significantly increased the biotransformation of iopromide in upflow anaerobic sludge blanket (UASB) reactors. Control UASB reactor (without humic material) achieved 31.6% of iopromide removal, while 80% was removed in UASB reactors supplied with each metal-humic acid complex. Further analyses indicated multiple transformation reactions taking place in iopromide including deiodination, N-dealkylation, decarboxylation and deacetylation. This is the first successful application of immobilized RM, which does not require a supporting material to maintain the solid-phase RM in long term operation of bioreactors. The proposed redox catalyst could be suitable for enhancing the redox conversion of different recalcitrant pollutants present in industrial effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical characterisation of MOX grinder sludge and process evaluation for its dry recycling

Energy Technology Data Exchange (ETDEWEB)

Mallik, G K; Fulzele, A K; Kothari, M; Bhargava, V K; Kamath, H S [Bhabha Atomic Research Centre, Tarapur (India). Advanced Fuel Fabrication Facility

1997-09-01

A large quantity of sludge (approximately 5%) is generated as a result of centreless grinding of MOX pellets. Plutonium and uranium are recovered from such sludge, consisting of coolant, resin and some metallic impurities, by a wet chemical route. A case has been made for the recycling of the sludge by an optimum dry route on the basis of chemical characterisation of sludge generated at Advanced Fuel Fabrication Facility using diamond grinding wheel. (author). 2 tabs.

Chemical characterisation of MOX grinder sludge and process evaluation for its dry recycling

International Nuclear Information System (INIS)

Mallik, G.K.; Fulzele, A.K.; Kothari, M.; Bhargava, V.K.; Kamath, H.S.

1997-01-01

A large quantity of sludge (approximately 5%) is generated as a result of centreless grinding of MOX pellets. Plutonium and uranium are recovered from such sludge, consisting of coolant, resin and some metallic impurities, by a wet chemical route. A case has been made for the recycling of the sludge by an optimum dry route on the basis of chemical characterisation of sludge generated at Advanced Fuel Fabrication Facility using diamond grinding wheel. (author). 2 tabs

Sludge Reduction by Lumbriculus Variegatus in Ahvaz Wastewater Treatment Plant

Directory of Open Access Journals (Sweden)

Tim Hendrickx

2012-08-01

Full Text Available Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensivehealth hazards. Application of aquatic worm is an approach to decrease the amount of biological waste sludge produced in wastewater treatment plants. In the present research reduction of the amount of waste sludge from Ahvaz wastewater treatment plant was studied with the aquatic worm Lumbriculus variegatus in a reactor concept. The sludge reduction in the reactor with worm was compared to sludge reduction in a blank reactor (without worm.The effects of changes in dissolved oxygen (DO concentration up to 3 mg/L (run 1 and up to 6 mg/L (run 2 were studied in the worm and blank reactors. No meaningful relationship was found between DO concentration and the rate of total suspended solids reduction. Theaverage sludge reductions were obtained as 33% (run 2 and 32% (run 1 in worm reactor,and 16% (run 1 and 12% (run 2 in the blank reactor. These results showed that the worm reactors may reduce the waste sludge between 2 and 2.75 times higher than in the blankconditions. The obtained results showed that the worm reactor has a high potential for use in large-scale sludge processing.

Removal of antibiotics in wastewater: Effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process.

Science.gov (United States)

Kim, Sungpyo; Eichhorn, Peter; Jensen, James N; Weber, A Scott; Aga, Diana S

2005-08-01

A study was conducted to examine the influence of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of tetracycline in the activated sludge processes. Two lab-scale sequencing batch reactors (SBRs) were operated to simulate the activated sludge process. One SBR was spiked with 250 microg/L tetracycline, while the other SBR was evaluated at tetracycline concentrations found in the influent of the wastewater treatment plant (WWTP) where the activated sludge was obtained. The concentrations of tetracyclines in the influent of the WWTP ranged from 0.1 to 0.6 microg/L. Three different operating conditions were applied during the study (phase 1-HRT: 24 h and SRT: 10 days; phase 2-HRT: 7.4 h and SRT: 10 days; and phase 3-HRT: 7.4 h and SRT: 3 days). The removal efficiency of tetracycline in phase 3 (78.4 +/- 7.1%) was significantly lower than that observed in phase 1 (86.4 +/- 8.7%) and phase 2 (85.1 +/- 5.4%) at the 95% confidence level. The reduction of SRT in phase 3 while maintaining a constant HRT decreased tetracycline removal efficiency. Sorption kinetics reached equilibrium within 24 h. Batch equilibrium experiments yielded an adsorption coefficient (Kads) of 8400 +/- 500 mL/g and a desorption coefficient (Kdes) of 22 600 +/- 2200 mL/g. No evidence of biodegradation for tetracycline was observed during the biodegradability test, and sorption was found to be the principal removal mechanism of tetracycline in activated sludge.

Adverse effects of erythromycin on the structure and chemistry of activated sludge

International Nuclear Information System (INIS)

Louvet, J.N.; Giammarino, C.; Potier, O.; Pons, M.N.

2010-01-01

This study examines the effects of erythromycin on activated sludge from two French urban wastewater treatment plants (WWTPs). Wastewater spiked with 10 mg/L erythromycin inhibited the specific evolution rate of chemical oxygen demand (COD) by 79% (standard deviation 34%) and the specific N-NH 4 + evolution rate by 41% (standard deviation 25%). A temporary increase in COD and tryptophan-like fluorescence, as well as a decrease in suspended solids, were observed in reactors with wastewater containing erythromycin. The destruction of activated sludge flocs was monitored by automated image analysis. The effect of erythromycin on nitrification was variable depending on the sludge origin. Erythromycin inhibited the specific nitrification rate in sludge from one WWTP, but increased the nitrification rate at the other facility. - Erythromycin toxicity on activated sludge is expected to reduce pollution removal.

Municipal solid waste generation and disposal in Robe town, Ethiopia.

Science.gov (United States)

Erasu, Duguma; Faye, Tesfaye; Kiros, Amaha; Balew, Abel

2018-04-20

The amount of solid waste generated in developing countries is rising from time to time due to economic growth, change in consumer behavior and lifestyles of people. But it is hard to manage and handle the increase of solid waste with existing waste management infrastructure. Thus, the management system of solid waste is very poor and become a serious problem. The main purpose of this study is to quantify the volume of solid waste generated and investigate factors affecting generation and disposal of wastes in the study area. The result of this study indicated that total waste generated from households was about 97.092kg/day.Furthermore, the study reveals that the solid waste generation rate of the town is 0.261kg/person/day.About 57.5% of solid waste is properly disposed of to landfill site whereas the remaining 42.5% is illegally dumped at the roadsides and open fields. Implication Statement Nowadays, in developing countries there is high concentration of people in urban areas and cause for the generation of enormous concentration of municipal waste in urban areas. Therefore this finding will be important for various policy makers and town planners. It may also serve as a benchmark for the municipal authorities of the town for whom the problem is still invisible and negligible and can push environmental protection authorities to reexamine the implementation of their policies and strategies with regard to the broader issues of human and environmental health condition of town dwellers.

Phase chemistry and radionuclide retention from simulated tank sludges

International Nuclear Information System (INIS)

KRUMHANSL, JAMES L.; LIU, J.; ARTHUR, SARA E.; HUTCHERSON, SHEILA K.; QIAN, MORRIS; ANDERSON, HOWARD L.

2000-01-01

Decommissioning high level nuclear waste tanks will leave small amounts of residual sludge clinging to the walls and floor of the structures. The permissible amount of material left in the tanks depends on the radionuclide release characteristics of the sludge. At present, no systematic process exists for assessing how much of the remaining inventory will migrate, and which radioisotopes will remain relatively fixed. Working with actual sludges is both dangerous and prohibitively expensive. Consequently, methods were developed for preparing sludge simulants and doping them with nonradioactive surrogates for several radionuclides and RCRA metals of concern in actual sludges. The phase chemistry of these mixes was found to be a reasonable match for the main phases in actual sludges. Preliminary surrogate release characteristics for these sludges were assessed by lowering the ionic strength and pH of the sludges in the manner that would occur if normal groundwater gained access to a decommissioned tank. Most of the Se, Cs and Tc in the sludges will be released into the first pulse of groundwater passing through the sludge. A significant fraction of the other surrogates will be retained indefinitely by the sludges. This prolonged sequestration results from a combination coprecipitated and sorbed into or onto relatively insoluble phases such as apatite, hydrous oxides of Fe, Al, Bi and rare earth oxides and phosphates. The coprecipitated fraction cannot be released until the host phase dissolves or recrystallizes. The sorbed fraction can be released by ion exchange processes as the pore fluid chemistry changes. However, these releases can be predicted based on a knowledge of the fluid composition and the surface chemistry of the solids. In this regard, the behavior of the hydrous iron oxide component of most sludges will probably play a dominant role for many cationic radionuclides while the hydrous aluminum oxides may be more important in governing anion releases

Research on Treatment Technology and Device of Oily Sludge

Science.gov (United States)

Wang, J. Q.; Shui, F. S.; Li, Q. F.

2017-12-01

Oily sludge is a solid oily waste, which is produced during the process of oil exploitation, transportation, refining and treatment of oily sewage. It contains a great number of hazardous substance, and is difficult to handle with. To solve the problem of waste resources of oil sludge with high oil content and usually not easy to aggregate during the preparation of profile control agent, a new oily sludge treatment device was developed. This device consists of heat supply unit, flush and filter unit, oil removal unit and dehydration unit. It can effectively clean and filter out the waste from oily sludge, recycle the oil resources and reduce the water content of the residue. In the process of operation, the water and chemical agent are recycled in the device, eventually producing little sewage. The device is small, easy to move and has high degree of automation control. The experimental application shows that the oil removal rate of the oily sludge is up to 70%, and the higher the oil content rate the better the treatment.

New technology for recyclingmaterials from oily cold rollingmill sludge

Science.gov (United States)

Liu, Bo; Zhang, Shen-gen; Tian, Jian-jun; Pan, De-an; Meng, Ling; Liu, Yang

2013-12-01

Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of "hydrometallurgical treatment + hydrothermal synthesis" was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.

Incineration of Sludge in a Fluidized-Bed Combustor

OpenAIRE

Chien-Song Chyang; Yu-Chi Wang

2017-01-01

For sludge disposal, incineration is considered to be better than direct burial because of regulations and space limitations in Taiwan. Additionally, burial after incineration can effectively prolong the lifespan of a landfill. Therefore, it is the most satisfactory method for treating sludge at present. Of the various incineration technologies, the fluidized bed incinerator is a suitable choice due to its fuel flexibility. In this work, sludge generated from industrial plants was treated in ...

Chemical modeling of waste sludges

International Nuclear Information System (INIS)

Weber, C.F.; Beahm, E.C.

1996-10-01

The processing of waste from underground storage tanks at the Oak Ridge National Laboratory (ORNL) and other facilities will require an understanding of the chemical interactions of the waste with process chemicals. Two aspects of sludge treatment should be well delineated and predictable: (1) the distribution of chemical species between aqueous solutions and solids, and (2) potential problems due to chemical interactions that could result in process difficulties or safety concerns. It is likely that the treatment of waste tank sludge will begin with washing, followed by basic or acidic leaching. The dissolved materials will be in a solution that has a high ionic strength where activity coefficients are far from unity. Activity coefficients are needed in order to calculate solubilities. Several techniques are available for calculating these values, and each technique has its advantages and disadvantages. The techniques adopted and described here is the Pitzer method. Like any of the methods, prudent use of this approach requires that it be applied within concentration ranges where the experimental data were fit, and its use in large systems should be preceded by evaluating subsystems. While much attention must be given to the development of activity coefficients, other factors such as coprecipitation of species and Ostwald ripening must also be considered when one aims to interpret results of sludge tests or to predict results of treatment strategies. An understanding of sludge treatment processes begins with the sludge tests themselves and proceeds to a general interpretation with the aid of modeling. One could stop with only data from the sludge tests, in which case the table of data would become an implicit model. However, this would be a perilous approach in situations where processing difficulties could be costly or result in concerns for the environment or health and safety

The treatment and disposal of oily solids

International Nuclear Information System (INIS)

Wright, R.A.D.; Noordhuis, B.R.

1991-01-01

Oily solids are generated as a waste product of Brunel Shell Petroleum's drilling and production activities. The main sources are waste oil based mud, tank bottom sludges, and oil contaminated soil. The oily solids are stored in a purpose built holding basin which is gradually being filled up. The need for appropriate treatment and an acceptable means of final disposal of the solids has been recognized as an item for attention in the Company's Environmental Management Plan. The paper describes the resulting feasibility study which is evaluating the relative merits of processes such as incineration, lime stabilization, and landfarming. The feasibility study is considering the quantity and properties of the solids, the environmental conditions in Brunei, the availability of treatment services in the country, and the need to define acceptable environmental criteria for the treatment and disposal methods. The way in which these factors influence the study are discussed

Improving the sludge conditioning potential of moringa seed

Science.gov (United States)

Ademiluyi, Joel O.; Eze, Romanus M.

1990-01-01

In the search for a cheaper material to effectively condition sludge, oil-free moringa seed was prepared and tested. A Soxhlet apparatus was used to extract the oil from moringa seed ( Moringa oleifera). The oil-free seed (marc) has been found to have higher conditioning potential than the ordinary moringa seed. However, the traditional ferric chloride is still a better sludge conditioner than moringa seed marc. For the digested domestic sludge used, optimum conditioning dosages were found to be 0.6, 0.80, and 1.10% of the total solids for ferric chloride, marc of the moringa seed, and ordinary moringa seed, respectively. Since little or no operational material is lost in the extraction process, the moringa seed marc is a promising conditioner in place of the ordinary seed.

Monitoring and optimizing the co-composting of dewatered sludge: a mixture experimental design approach.

Science.gov (United States)

Komilis, Dimitrios; Evangelou, Alexandros; Voudrias, Evangelos

2011-09-01

The management of dewatered wastewater sludge is a major issue worldwide. Sludge disposal to landfills is not sustainable and thus alternative treatment techniques are being sought. The objective of this work was to determine optimal mixing ratios of dewatered sludge with other organic amendments in order to maximize the degradability of the mixtures during composting. This objective was achieved using mixture experimental design principles. An additional objective was to study the impact of the initial C/N ratio and moisture contents on the co-composting process of dewatered sludge. The composting process was monitored through measurements of O(2) uptake rates, CO(2) evolution, temperature profile and solids reduction. Eight (8) runs were performed in 100 L insulated air-tight bioreactors under a dynamic air flow regime. The initial mixtures were prepared using dewatered wastewater sludge, mixed paper wastes, food wastes, tree branches and sawdust at various initial C/N ratios and moisture contents. According to empirical modeling, mixtures of sludge and food waste mixtures at 1:1 ratio (ww, wet weight) maximize degradability. Structural amendments should be maintained below 30% to reach thermophilic temperatures. The initial C/N ratio and initial moisture content of the mixture were not found to influence the decomposition process. The bio C/bio N ratio started from around 10, for all runs, decreased during the middle of the process and increased to up to 20 at the end of the process. The solid carbon reduction of the mixtures without the branches ranged from 28% to 62%, whilst solid N reductions ranged from 30% to 63%. Respiratory quotients had a decreasing trend throughout the composting process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Possibility of sludge conditioning and dewatering with rice husk biochar modified by ferric chloride.

Science.gov (United States)

Wu, Yan; Zhang, Panyue; Zhang, Haibo; Zeng, Guangming; Liu, Jianbo; Ye, Jie; Fang, Wei; Gou, Xiying

2016-04-01

Rice husk biochar modified by FeCl3 (MRB-Fe) was used to enhance sludge dewaterability in this study. MRB-Fe preparation conditions and dosage were optimized. Mechanisms of MRB-Fe improving sludge dewaterability were investigated. The optimal modification conditions were: FeCl3 concentration, 3mol/L; ultrasound time, 1h. The optimal MRB-Fe dosage was 60% DS. Compared with raw sludge, the sludge specific resistance to filtration (SRF) decreased by 97.9%, the moisture content of sludge cake decreased from 96.7% to 77.9% for 6min dewatering through vacuum filtration under 0.03MPa, the SV30% decreased from 96% to 60%, and the net sludge solids yield (YN) increased by 28 times. Positive charge from iron species on MRB-Fe surface counteracted negative charge of sludge flocs to promote sludge settleability and dewaterability. Meanwhile, MRB-Fe kept a certain skeleton structure in sludge cake, making the moisture pass through easily. Using MRB-Fe, therefore, for sludge conditioning and dewatering is promising. Copyright © 2016. Published by Elsevier Ltd.

Dynamic modeling of sludge compaction and consolidation processes in wastewater secondary settling tanks.

Science.gov (United States)

Abusam, A; Keesman, K J

2009-01-01

The double exponential settling model is the widely accepted model for wastewater secondary settling tanks. However, this model does not estimate accurately solids concentrations in the settler underflow stream, mainly because sludge compression and consolidation processes are not considered. In activated sludge systems, accurate estimation of the solids in the underflow stream will facilitate the calibration process and can lead to correct estimates of particularly kinetic parameters related to biomass growth. Using principles of compaction and consolidation, as in soil mechanics, a dynamic model of the sludge consolidation processes taking place in the secondary settling tanks is developed and incorporated to the commonly used double exponential settling model. The modified double exponential model is calibrated and validated using data obtained from a full-scale wastewater treatment plant. Good agreement between predicted and measured data confirmed the validity of the modified model.

Unified Modeling of Filtration and Expression of Biological Sludge

DEFF Research Database (Denmark)

Sørensen, Peter Borgen

Dewatering is a costly operation in both industry, e.g . when dewatering drilling mud, harbor sludge or biomass, and at municipal wastewater treatment plants when dewatering biological sludges. In practice, design and operation of dewatering equipment are mostly based on empirical knowledge, and ......, and normally results are not satisfactory, e.g. in terms of cake solids or capacity of equipment. Thus, there is a need for theoretical and technical developments to improve dewatering performance, based on better scientific knowledge and well defined principles and rules....

Degradation of organic pollutants and characteristics of activated sludge in an anaerobic/anoxic/oxic reactor treating chemical industrial wastewater

Directory of Open Access Journals (Sweden)

Dong Wang

2014-09-01

Full Text Available A laboratory-scale anaerobic/anoxic/oxic system operated at the hydraulic retention times (HRT of 20, 40, and 60 h with mixed liquor suspended solids (MLSS concentrations of 3 g/L and 6 g/L was considered for treating chemical industrial wastewater rich in complex organic compounds and total dissolved solids. Extending the HRT and increasing the MLSS concentration resulted in higher removal efficiency for chemical oxygen demand at 72%. Organic compounds in wastewater could be classified into easily-removed and refractory compounds during treatment. The easily-removed compounds consisted primarily of ethers, alcohols, and aldehydes, whereas the refractory compounds included mainly oxygen-containing heterocyclic and benzene-containing compounds. Results from energy-dispersive X-ray spectroscopy showed that several metal ions accumulated in activated sludge, particularly Fe(III. Fe accumulated mainly on the surface of sludge floc pellets and resulted in the compactness of activated sludge, which caused the values of mixed liquor volatile suspended solids /MLSS and sludge volume index to decrease.

Simulation of substrate degradation in composting of sewage sludge

International Nuclear Information System (INIS)

Zhang Jun; Gao Ding; Chen Tongbin; Zheng Guodi; Chen Jun; Ma Chuang; Guo Songlin; Du Wei

2010-01-01

To simulate the substrate degradation kinetics of the composting process, this paper develops a mathematical model with a first-order reaction assumption and heat/mass balance equations. A pilot-scale composting test with a mixture of sewage sludge and wheat straw was conducted in an insulated reactor. The BVS (biodegradable volatile solids) degradation process, matrix mass, MC (moisture content), DM (dry matter) and VS (volatile solid) were simulated numerically by the model and experimental data. The numerical simulation offered a method for simulating k (the first-order rate constant) and estimating k 20 (the first-order rate constant at 20 o C). After comparison with experimental values, the relative error of the simulation value of the mass of the compost at maturity was 0.22%, MC 2.9%, DM 4.9% and VS 5.2%, which mean that the simulation is a good fit. The k of sewage sludge was simulated, and k 20 , k 20s (first-order rate coefficient of slow fraction of BVS at 20 o C) of the sewage sludge were estimated as 0.082 and 0.015 d -1 , respectively.

Gas Generation from Solids in Aqueous Suspensions

International Nuclear Information System (INIS)

Meisel, D.; Schatz, T.

1999-01-01

The presence of solid particles suspended in solution may change the radiation-induced chemistry of a system in many ways. Catalytic surface effects may manifest themselves through the acceleration or inhibition of various reactions. As importantly, the yield of primary radiolysis products may be affected as the solids absorb a significant fraction of the radiation energy. The latter is the subject of this study. We explore the possibility that absorption of radiation by the solid particles may initiate chemistry in the water. This is a question of fundamental as well as practical significance. On the fundamental side we ask whether electron-hole pairs generated in the solid phase can escape and cross into the aqueous phase and initiate chemical reactions such as gas generation and how this possibility depends on the energy levels of the material and on particle size. From a practical angle, such questions are directly relevant to any heterogeneous system exposed to radiation. High-level waste temporarily stored in underground tanks, low-level waste permanently stored in humid grout, or soil particles migrating in geological formations are but a few examples

Ash behavior during hydrothermal treatment for solid fuel applications. Part 2: Effects of treatment conditions on industrial waste biomass

International Nuclear Information System (INIS)

Mäkelä, Mikko; Yoshikawa, Kunio

2016-01-01

Highlights: • Effect of treatment conditions on composition and solubility of ash. • Ash dissolution and yield governed by liquid pH and calcium carbonate solubility. • Dissolution of calcium carbonate decreases ash fusion temperature during combustion. • Decreasing the ash content of sludge can weaken ash properties for combustion. - Abstract: This second half of our work on ash behavior concentrates on the effects of hydrothermal treatment conditions on paper sludge. Ash composition and solubility were determined based on treatment temperature, reactor solid load and liquid pH using experimental design and univariate regression methods. In addition, ash properties for combustion were evaluated based on recent developments on ash classification. Based on the results, all experimental variables had a statistically significant effect on ash yields. Only reactor solid load was statistically insignificant for char ash content, which increased based on increasing treatment temperature due to the decomposition of organic components. Ash dissolution and ash yield were governed by liquid pH and the generation of acids mainly due to the solubility of calcium carbonate identified as the main mineral species of paper sludge. Dissolution of calcium carbonate however decreased ash fusion temperatures more likely causing problems during char incineration. This indicated that decreasing the ash content of sludge during hydrothermal treatment can actually weaken ash properties for solid fuel applications.

Extracellular polymeric substances (EPS) producing bacterial strains of municipal wastewater sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering.

Science.gov (United States)

Bala Subramanian, S; Yan, S; Tyagi, R D; Surampalli, R Y

2010-04-01

Wastewater treatment plants often face the problems of sludge settling mainly due to sludge bulking. Generally, synthetic organic polymer and/or inorganic coagulants (ferric chloride, alum and quick lime) are used for sludge settling. These chemicals are very expensive and further pollute the environment. Whereas, the bioflocculants are environment friendly and may be used to flocculate the sludge. Extracellular polymeric substances (EPS) produced by sludge microorganisms play a definite role in sludge flocculation. In this study, 25 EPS producing strains were isolated from municipal wastewater treatment plant. Microorganisms were selected based on EPS production properties on solid agar medium. Three types of EPS (slime, capsular and bacterial broth mixture of both slime and capsular) were harvested and their characteristics were studied. EPS concentration (dry weight), viscosity and their charge (using a Zetaphoremeter) were also measured. Bioflocculability of obtained EPS was evaluated by measuring the kaolin clay flocculation activity. Six bacterial strains (BS2, BS8, BS9, BS11, BS15 and BS25) were selected based on the kaolin clay flocculation. The slime EPS was better for bioflocculation than capsular EPS and bacterial broth. Therefore, extracted slime EPS (partially purified) from six bacterial strains was studied in terms of sludge settling [sludge volume index (SVI)] and dewatering [capillary suction time (CST)]. Biopolymers produced by individual strains substantially improved dewaterability. The extracted slime EPS from six different strains were partially characterized. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Co-composting as an oxygen stabilization of an organic fraction of municipal solid waste and industrial sewage sludge.

Science.gov (United States)

Milczarek, M; Neczaj, E; Parkitna, K

2013-01-01

The purpose of this work is to study the characteristics of the co-composting of municipal solid waste (MSW), sewage sludge, grass and sawdust. Differing proportions of biodegradable waste were investigated through changes of temperature, oxygen consumption, organic matters, moisture content, carbon, nitrogen, C/N ratio as well as heavy metals and pathogen microorganisms content. The present study has shown that addition of MSW above 10% had a negative impact on the composting process. The initial C/N of the mixtures with a higher MSW content was below 18. Lower losses of organic matter occurred during composting for the mixture with the highest addition of MSW. Although studies have shown that composting is a good method for the disposal of organic waste additional research is required in order to optimize the organic and nitrogen compounds degradation during the co-composting process. In conclusion, a 1:4:4:1 mixture of MSW:sewage sludge:grass:sawdust is recommended because it can achieve high temperature as well as the highest organic matter degradation and highest N content in the final composting product. The concentration of heavy and light metals in all composts was within the limits of regulation of the Polish Minister of Agriculture and Rural Development.

Hydrogen generation during melter feed preparation of Tank 42 sludge and salt washed loaded CST in the Defense Waste Processing Facility

International Nuclear Information System (INIS)

Daniel, W.E.

1999-01-01

The main objective of these scoping tests was to measure the rate of hydrogen generation in a series of experiments designed to duplicate the expected SRAT and SME processing conditions in laboratory scale vessels. This document details the testing performed to determine the maximum hydrogen generation expected with a coupled flowsheet of sludge, loaded CST [crystalline silicotitanate], and frit

Soil cadmium mobility as a consequence of sewage sludge disposal

Energy Technology Data Exchange (ETDEWEB)

Lamy, I. [Station de Science du Sol, Versailles (France); Bourgeois, S.; Bermond, A. [Institut National Agronomique, Paris (France)

1993-10-01

Anaerobically digested liquid sewage sludge was applied as a single treatment to a loamy hydromorphic drained soil, characteristic of agricultural soils in the North of France, at a rate of 11 Mg of dry solids ha{sup -1}. Total Cd concentrations of drainage waters for both amended and unamended plots were monitored at selected times to follow the mobility of Cd after sludge disposal. The drained ground-water of the plot that exhibited the highest discharge of sludge soluble organic matter (SSOM) exhibited about twice the Cd levels of the control plot during the first few weeks following sludge disposal (average of 3 and 1.5 {mu}g L{sup -1} respectively). Laboratory experiments were conducted to provide estimates of the relative binding strength of Cd-soil interactions as well as Cd-SSOM interactions. The behavior of Cd in a mixed sludge-soil system showed that the addition of sludge soluble organic matter to the soil led to a decrease in the sorption of this cation across the pH range between 5 and 7. The laboratory studies highlighted the role of soluble organic matter in soil Cd speciation, and can be used to speculate on the perturbations induced by high levels of sludge soluble organic matter introduced into a soil.

Effects of ultrasonic disintegration of excess sewage sludge.

Science.gov (United States)

Zielewicz, Ewa

2016-10-01

Breaking down sludge floc (sonodyspergation effect) and destruction of the cell membranes of microorganisms forming floc is a direct effect of ultrasonic disintegration of sludge excess. This results in release of organic material by liquid sludge (the sonolysis effect). Desired technological effects of the disintegration are: to shorten the hydrolytic phase of fermentation, to increase the production of biogas (source of renewable energy) and an increased mineralization (stability) of fermented sludge. The presented study demonstrates research covering thickened excess sludge of various physicochemical properties, collected from nine municipal sewage treatment plants. The sludge was subjected to ultrasonic disintegration using three differently constructed disintegrators and different proportions of sonification area. Direct effects of disintegration were monitored and recorded using selected indicators describing changes in the properties of sludge and increase of substance dispersed and dissolved in the supernatant liquid to be filtered. Studies have demonstrated that those (direct) effects of ultrasonic disintegration depend on the physicochemical properties of the sludge (foremost the concentration of dry solids) that determine their variable susceptibility to the disintegration methods. The direct effects also depend on optimal process conditions (which consist of the construction of the ultrasonic disintegrator), the geometric proportions of the sonication area and the operating parameters of disintegration (which could be appropriately matched to the characteristics of sludge). The most preferable results were obtained for ultrasonic disintegration of sludge with a dry matter concentration C 0 < 4.2 %. The highest effect of sonolysis-an almost 30-fold increase in the COD dissolved in the supernatant-was obtained for the sludge of lowest dry matter (C 0 = 2.0 %), which was sonicated in a reactor with a short transducer of the largest radiating surface

A Survey of Municipal Solid Waste Generation in 22 Regions of Tehran With Solid Waste Reduction Approach