Optimization of combined in-vessel composting process and chemical oxidation for remediation of bottom sludge of crude oil storage tanks.

PubMed

Koolivand, Ali; Naddafi, Kazem; Nabizadeh, Ramin; Saeedi, Reza

2017-07-31

In this research, removal of petroleum hydrocarbons from oily sludge of crude oil storage tanks was investigated under the optimized conditions of in-vessel composting process and chemical oxidation with H 2 O 2 and Fenton. After determining the optimum conditions, the sludge was pre-treated with the optimum state of the oxidation process. Then, the determined optimum ratios of the sludge to immature compost were composted at a C:N:P ratio of 100:5:1 and moisture content of 55% for a period of 10 weeks. Finally, both pre-treated and composted mixtures were again oxidized with the optimum conditions of the oxidants. Results showed that total petroleum hydrocarbons (TPH) removal of the 1:8 and 1:10 composting reactors which were pre-treated with H 2 O 2 were 88.34% and 90.4%, respectively. In addition, reduction of TPH in 1:8 and 1:10 composting reactors which were pre-treated with Fenton were 83.90% and 84.40%, respectively. Without applying the pre-treatment step, the composting reactors had a removal rate of about 80%. Therefore, pre-treatment of the reactors increased the TPH removal. However, post-oxidation of both pre-treated and composted mixtures reduced only 13-16% of TPH. Based on the results, remarkable overall removal of TPH (about 99%) was achieved by using chemical oxidation and subsequent composting process. The study showed that chemical oxidation with H 2 O 2 followed by in-vessel composting is a viable choice for the remediation of the sludge.

Effective water content reduction in sewage wastewater sludge using magnetic nanoparticles.

PubMed

Lakshmanan, Ramnath; Kuttuva Rajarao, Gunaratna

2014-02-01

The present work compares the use of three flocculants for sedimentation of sludge and sludge water content from sewage wastewater i.e. magnetic iron oxide nanoparticles (MION), ferrous sulfate (chemical) and Moringa crude extract (protein). Sludge water content, wet/dry weight, turbidity and color were performed for, time kinetics and large-scale experiment. A 30% reduction of the sludge water content was observed when the wastewater was treated with either protein or chemical coagulant. The separation of sludge from wastewater treated with MION was achieved in less than 5min using an external magnet, resulted in 95% reduction of sludge water content. Furthermore, MION formed denser flocs and more than 80% reduction of microbial content was observed in large volume experiments. The results revealed that MION is efficient in rapid separation of sludge with very low water content, and thus could be a suitable alternative for sludge sedimentation and dewatering in wastewater treatment processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of irradiation intensity and pH on nutrients release and solids destruction of waste activated sludge using the microwave-enhanced advanced oxidation process.

PubMed

Chan, W I; Liao, P H; Lo, K V

2010-11-01

Using the microwave-enhanced advanced oxidation process (MW/H2O2-AOP), the pH and irradiation intensity on waste activated sludge samples were investigated to provide insight to the athermal effects on nutrients release, solids destruction, particle size distribution and dewaterability, and to demonstrate their interrelationships. Carbonaceous matters and nutrients released into solution depended on the irradiation intensity and time. Higher irradiation levels tended to be more effective in the solubilization of nutrients and had more pronounced effects in the dewaterability of sludge. In terms of particle size distribution, detectable particles increased in size for treatments in acidic conditions, while the dewaterability of treated sludge was improved. In treatments under neutral and alkaline conditions, the particle size range increased, with more small particles formed, thereby significantly deteriorating the dewaterability of sludge treated in alkaline conditions. The best results for the solubilization of nutrients were in alkaline conditions with high irradiation power, but dewaterability of the sludge was compromised. Sludge treatment with the MW/H2O2-AOP in acidic conditions with high irradiation power yielded the best dewaterable sludge and significant nutrient solubilization; therefore, it is the recommended treatment condition for activated sludge.

Recycling of Cu powder from industrial sludge by combined acid leaching, chemical exchange and ferrite process.

PubMed

Tu, Yao-Jen; Chang, Chien-Kuei; You, Chen-Feng; Lou, Jie-Chung

2010-09-15

A method in combination of acid leaching, chemical exchange and ferrite process was applied to recycle copper and confer higher chemical stability to the sludge generated from etching process in printed circuit board industry. Ninety-five percent copper could be recycled in the form of powder from the sludge. Moreover, not only the wastewater after chemical exchange can be treated to fulfill the effluent standard, but also the sludge can satisfy the toxicity characteristic leaching procedure (TCLP) limits made by Taiwan's environmental protection administration. Copyright 2010 Elsevier B.V. All rights reserved.

Effect of various types of thermochemical processing of sewage sludges on phosphorus speciation, solubility, and fertilization performance.

PubMed

Steckenmesser, Daniel; Vogel, Christian; Adam, Christian; Steffens, Diedrich

2017-04-01

Sewage sludge has one of the highest phosphorus (P) recovery potentials of all waste materials. Therefore, P-recycling from sewage sludge could contribute to closing the P-cycle. Recently, various thermal processes for P-recovery have been developed, but there is still a demand for information on the effect of different process parameters (e.g. additives and temperature) on P-speciation and especially on the fertilization performance. In the present study, two common methods (low-temperature conversion at 400-500°C and thermochemical treatment at 950°C) were investigated and combined to produce highly bioavailable P-fertilizers from two different types of sewage sludge based on chemical phosphorus precipitation (Chem-P) and enhanced biological phosphorus removal (Bio-P). The results of P-fractionation, X-ray diffraction analysis, and pot experiments with maize showed that Bio-P sludges attain high P-plant-availability after treatment at low temperatures (400°C). In contrast, Chem-P sludges can adequately be treated at higher temperatures under reductive conditions with sodium additives to form highly bioavailable calcium-sodium-phosphate. Additionally, also highly heavy-metal contaminated sludges can be thermochemically treated at high temperatures to achieve the legal requirements for fertilizers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method for processing aqueous wastes

DOEpatents

Pickett, John B.; Martin, Hollis L.; Langton, Christine A.; Harley, Willie W.

1993-01-01

A method for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply.

Anionic surfactants in treated sewage and sludges: risk assessment to aquatic and terrestrial environments.

PubMed

Mungray, Arvind Kumar; Kumar, Pradeep

2008-05-01

Compared to low concentrations of anionic surfactants (AS) in activated sludge process effluents (ASP) (<0.2 mg/L), upflow anaerobic sludge blanket-polishing pond (UASB-PP) effluents were found to contain very high concentrations of AS (>3.5 mg/L). AS (or linear alkylbenzen sulfonate, LAS) removals >99% have been found for ASP while in case of UASB-PP it was found to be < or = 30%. AS concentrations averaged 7347 and 1452 mg/kg dry wt. in wet UASB and dried sludges, respectively. Treated sewage from UASB based sewage treatment plants (STPs) when discharged to aquatic ecosystems are likely to generate substantial risk. Post-treatment using 1-1.6d detention, anaerobic, non-algal polishing ponds was found ineffective. Need of utilizing an aerobic method of post-treatment of UASB effluent in place of an anaerobic one has been emphasized. Natural drying of UASB sludges on sludge drying beds (SDBs) under aerobic conditions results in reduction of adsorbed AS by around 80%. Application of UASB sludges on SDBs was found simple, economical and effective. While disposal of treated UASB effluent may cause risk to aquatic ecosystems, use of dried UASB sludges is not likely to cause risk to terrestrial ecosystems.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1977-11-01

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

Potential of activated sludge disintegration.

PubMed

Boehler, M; Siegrist, H

2006-01-01

The disposal of sewage sludge and the agricultural use of stabilised sludge are decreasing due to more stringent regulations in Europe. An increasing fraction of sewage sludge must therefore be dewatered, dried, incinerated and the ashes disposed of in landfills. These processes are cost-intensive and also lead to the loss of valuable phosphate resources incorporated in the sludge ash. The implementation of processes that could reduce excess sludge production and recycle phosphate is therefore recommended. Disintegration of biological sludge by mechanical, thermal and physical methods could significantly reduce excess sludge production, improve the settling properties of the sludge and reduce bulking and scumming. The solubilised COD could also improve denitrification if the treated sludge is recycled to the anoxic zone. However, disintegration partly inhibits and kills nitrifiers and could therefore shorten their effective solid retention time, thus reducing the safety of the nitrification. This paper discusses the potential of disintegration on sludge reduction, the operating stability of nitrification, the improvement of denitrification and also presents an energy and cost evaluation.

Energy saving control strategies for Haliscomenobacter hydrossis filamentous sludge bulking in the A/O process treating real low carbon/nitrogen domestic wastewater.

PubMed

Jiao, Erlong; Gao, Chundi; Li, Renfei; Tian, Ye; Peng, Yongzhen

2017-07-16

The control strategies of energy saving for filamentous sludge bulking were investigated in the A/O process under low dissolved oxygen (DO) with low carbon/nitrogen (C/N) ratio, and the dominant filamentous bacteria were identified by using fluorescent in situ hybridization. Initially, the sludge volume index reached nearly 500 mL/g and serious bulking occurred when the DO value was 0.5 mg/L, with Haliscomenobacter hydrossis as the major filamentous bacteria in the bulking sludge. Later on, the compartment number increased in the aerobic zone, increasing by this way DO, to control serious bulking. Increasing DO to 1 mg/L based on the increase of compartment number in the aerobic zone was the favorable controlling method, which solved the sludge loss, improved the effluent quality to the national discharge standard and allowed for energy costs saving. As a result, the effective control method for H. hydrossis filamentous sludge bulking provided the economical, convenient and longstanding method for most municipal wastewater treatment plants treating real low C/N domestic wastewater.

Occurrence and activity of Archaea in aerated activated sludge wastewater treatment plants.

PubMed

Gray, Neil D; Miskin, Ian P; Kornilova, Oksana; Curtis, Thomas P; Head, Ian M

2002-03-01

The occurrence, distribution and activity of archaeal populations within two aerated, activated sludge wastewater treatment systems, one treating domestic waste and the second treating mixed domestic and industrial wastewater, were investigated by denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR)-amplified ribosomal RNA gene fragments and process measurements. In the plant receiving mixed industrial and domestic waste the archaeal populations found in the mixed liquor were very similar to those in the influent sewage, though a small number of DGGE bands specific to the mixed liquor were identified. In contrast, the activated sludge treating principally domestic waste harboured distinct archaeal populations associated with the mixed liquor that were not prevalent in the influent sewage. We deduce that the Archaea in the plant treating mixed wastewater were derived principally from the influent, whereas those in the plant treating solely domestic waste were actively growing in the treatment plant. Archaeal 16S rRNA gene sequences related to the Methanosarcinales, Methanomicrobiales and the Methanobacteriales were detected. Methanogenesis was measured in activated sludge samples incubated under oxic and anoxic conditions, demonstrating that the methanogens present in both activated sludge plants were active only in anoxic incubations. The relatively low rates of methanogenesis measured indicated that, although active, the methanogens play a minor role in carbon turnover in activated sludge.

Impact of the excess sludge modification with selected chemical reagents on the increase of dissolved organic substances concentration compounds transformations in activated sludge.

PubMed

Zawieja, Iwona; Lidia, Wolny; Marta, Próba

2017-07-01

Submission of excess sludge initial disintegration process significantly affects the efficiency of anaerobic stabilization process. Expression of increasing the concentration of organic matter in dissolved form is to increase sludge disintegration. As a result of chemical modification is an increase of the chemical oxygen demand and the concentration of volatile fatty acids. The aim of this study was to determine the impact of the disintegration process with selected chemical reagents to increase the concentration of organic substances in dissolved form. The process of chemical disintegration of excess sludge was treated using the following reagents: Mg(OH) 2 , Ca(OH) 2 , HCl, H 2 SO 4 , H 2 O 2 . The modification was carried out at ambient temperature for 2, 6 and 24h. During sludge disintegration it was noticed the growth of indicators values that confirmed the susceptibility of prepared sludge to biodegradation. Copyright © 2017 Elsevier Inc. All rights reserved.

Inhibitory effect of high calcium concentration on municipal solid waste leachate treatment by the activated sludge process.

PubMed

Xia, Yi; He, Pin Jing; Pu, Hong Xia; Lü, Fan; Shao, Li Ming; Zhang, Hua

2017-05-01

This research focused on the inhibitory effects of Ca on the aerobic biological treatment of landfill leachate containing extremely high Ca concentrations. When the Ca concentration in leachate to be treated was more than 4500 mg l -1 , the total organic carbon removal rate was significantly reduced and the processing time to achieve the same removal efficiency was 1.4 times that in the control treatment without added Ca. In contrast, the total nitrogen and ammonia nitrogen (NH 4 + -N) removal efficiencies were positively related to the Ca concentration, increasing from 65.2% to 81.2% and from 69.2% to 83.7%, respectively, when the dosage of added Ca increased from zero to 8000 mg l -1 . During aerobic treatment, the reductions of solution Ca concentration were in the range of 1003-2274 mg l -1 and were matched with increases in the Ca content in the residual sludge. The inhibition threshold of Ca in the leachate treated by the activated sludge process appeared to be 4500 mg l -1 , which could be realized by controlling the influent Ca concentration and using an appropriate sludge return ratio in the activated sludge process.

Characteristics of sludge reduction in an integrated pretreatment and aerobic digestion process.

PubMed

Hwang, S; Jang, H; Lee, M; Song, J; Kim, S

2006-01-01

In this study, integrated pretreatments and aerobic digestion processes were investigated in order to provide a feasible alternative that can achieve effective sludge reduction. An ozone treatment in the presence of ionic manganese, a catalyst, increased the sludge reduction ratio three times higher than that of a single ozonation, presumably due to an increase in OH radical production. The ozone treatment yielded the effective sludge reduction ratio with an increasing ozone dosage, and an effective dosage of the catalyst was found to be 4 mg-Mn/g-TS. When a mechanical pretreatment and an ozone/catalyst were applied in a series, the integrated process, even at a half mechanical intensity and a half level of ozone dosage, showed higher and faster sludge reduction than each single process did. In addition, the integrated pretreatment process showed the highest dewaterability of the treated sludges. A ratio of sludge cake generation, which was newly introduced to quantify overall performance of sludge treatment processes, showed that the integrated pretreatment followed by the aerobic digestion yielded approximately a half of the sludge cake volume compared to the single aerobic digestion. Therefore, the integrated pretreatment can be a feasible method for the effective reduction of total suspended solid and the final volume.

Biosolids accumulation and biodegradation of domestic wastewater treatment plant sludge by developed liquid state bioconversion process using a batch fermenter.

PubMed

Alam, Md Zahangir; Fakhru'l-Razi, A; Molla, Abul H

2003-09-01

The biosolids accumulation and biodegradation of domestic wastewater treatment plant (DWTP) sludge by filamentous fungi have been investigated in a batch fermenter. The filamentous fungi Aspergillus niger and Penicillium corylophilum isolated from wastewater and DWTP sludge was used to evaluate the treatment performance. The optimized mixed inoculum (A. niger and P. corylophilum) and developed process conditions (co-substrate and its concentration, temperature, initial pH, inoculum size, and aeration and agitation rate) were incorporated to accelerate the DWTP sludge treatment process. The results showed that microbial treatment of higher strength of DWTP sludge (4% w/w of TSS) was highly influenced by the liquid state bioconversion (LSB) process. In developed bioconversion processes, 93.8 g/kg of biosolids was enriched with fungal biomass protein of 30 g/kg. Enrichment of nutrients such as nitrogen (N), phosphorous (P), potassium (K) in biosolids was recorded in 6.2% (w/w), 3.1% (w/w) and 0.15% (w/w) from its initial values of 4.8% (w/w), 2.0% (w/w) and 0.08% (w/w) respectively after 10 days of fungal treatment. The biodegradation results revealed that 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 COD in treated DWTP sludge supernatant were removed after 8 days of microbial treatment. The specific resistance to filtration (SRF) in treated sludge (1.4x10(12) m/kg) was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation compared to untreated sample (85x10(12) m/kg).

Energy recovery from thermal treatment of dewatered sludge in wastewater treatment plants.

PubMed

Yang, Qingfeng; Dussan, Karla; Monaghan, Rory F D; Zhan, Xinmin

Sewage sludge is a by-product generated from municipal wastewater treatment (WWT) processes. This study examines the conversion of sludge via energy recovery from gasification/combustion for thermal treatment of dewatered sludge. The present analysis is based on a chemical equilibrium model of thermal conversion of previously dewatered sludge with moisture content of 60-80%. Prior to combustion/gasification, sludge is dried to a moisture content of 25-55% by two processes: (1) heat recovered from syngas/flue gas cooling and (2) heat recovered from syngas combustion. The electricity recovered from the combined heat and power process can be reused in syngas cleaning and in the WWT plant. Gas temperature, total heat and electricity recoverable are evaluated using the model. Results show that generation of electricity from dewatered sludge with low moisture content (≤ 70%) is feasible within a self-sufficient sludge treatment process. Optimal conditions for gasification correspond to an equivalence ratio of 2.3 and dried sludge moisture content of 25%. Net electricity generated from syngas combustion can account for 0.071 kWh/m(3) of wastewater treated, which is up to 25.4-28.4% of the WWT plant's total energy consumption.

Full-scale phosphorus recovery from digested waste water sludge in Belgium - part I: technical achievements and challenges.

PubMed

Marchi, A; Geerts, S; Weemaes, M; Schiettecatte, W; Wim, S; Vanhoof, C; Christine, V

2015-01-01

To date, phosphorus recovery as struvite in wastewater treatment plants has been mainly implemented on water phases resulting from dewatering processes of the sludge line. However, it is possible to recover struvite directly from sludge phases. Besides minimising the return loads of phosphorus from the sludge line to the water line, placing such a process within the sludge line is claimed to offer advantages such as a higher recovery potential, enhanced dewaterability of the treated sludge, and reduced speed of scaling in pipes and dewatering devices. In the wastewater treatment plant at Leuven (Belgium), a full-scale struvite recovery process from digested sludge has been tested for 1 year. Several monitoring campaigns and experiments provided indications of the efficiency of the process for recovery. The load of phosphorus from the sludge line returning to the water line as centrate accounted for 15% of the P-load of the plant in the reference situation. Data indicated that the process divides this phosphorus load by two. An improved dewaterability of 1.5% of dry solids content was achieved, provided a proper tuning of the installation. Quality analyses showed that the formed struvite was quite pure.

Method for processing aqueous wastes

DOEpatents

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

1993-12-28

A method is presented for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply. 4 figures.

A Guide for Developing Standard Operating Job Procedures for the Digestion Process Wastewater Treatment Facility. SOJP No. 10.

ERIC Educational Resources Information Center

Schwing, Carl M.

This guide describes standard operating job procedures for the digestion process of wastewater treatment facilities. This process is for reducing the volume of sludge to be treated in subsequent units and to reduce the volatile content of sludge. The guide gives step-by-step instructions for pre-startup, startup, continuous operating, shutdown,…

Impact of initial biodegradability on sludge anaerobic digestion enhancement by thermal pretreatment.

PubMed

Carrère, Hélène; Bougrier, Claire; Castets, Delphine; Delgenès, Jean Philippe

2008-11-01

Thermal treatments with temperature ranging from 60 to 210 degrees C were applied to 6 waste-activated sludge samples originating from high or medium load, extended aeration wastewater treatment processes that treated different wastewaters (urban, urban and industrial or slaughterhouse). COD sludge solubilisation was linearly correlated with the treatment temperature on the whole temperature range and independently of the sludge samples. Sludge batch mesophilic biodegradability increased with treatment temperature up to 190 degrees C. In this temperature range, biodegradability enhancement or methane production increase by thermal hydrolysis was shown to be a function of sludge COD solubilisation but also of sludge initial biodegradability. The lower the initial biodegradability means the higher efficiency of thermal treatment.

Evaluation of the Removal of Indicator Bacteria from Domestic Sludge Processed by Autothermal Thermophilic Aerobic Digestion (ATAD)

PubMed Central

Piterina, Anna V.; Bartlett, John; Pembroke, Tony J.

2010-01-01

The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing. PMID:20948933

Evaluation of the removal of indicator bacteria from domestic sludge processed by Autothermal Thermophilic Aerobic Digestion (ATAD).

PubMed

Piterina, Anna V; Bartlett, John; Pembroke, Tony J

2010-09-01

The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing.

Determination of the acute toxicities of physicochemical pretreatment and advanced oxidation processes applied to dairy effluents on activated sludge.

PubMed

Sivrioğlu, Özge; Yonar, Taner

2015-04-01

In this study, the acute toxicities of raw, physicochemical pre-treated, ozonated, and Fenton reagent applied samples of dairy wastewater toward activated sludge microorganisms, evaluated using the International Organization for Standardization's respiration inhibition test (ISO 8192), are presented. Five-day biological oxygen demand (BOD5) was measured to determine the biodegradability of physicochemical treatment, ozonation, Fenton oxidation or no treatment (raw samples) of dairy wastewater. Chemical pretreatment positively affected biodegradability, and the inhibition exhibited by activated sludge was removed to a considerable degree. Ozonation and the Fenton process exhibited good chemical oxygen demand removal (61%) and removal of toxins. Low sludge production was observed for the Fenton process applied to dairy effluents. We did not determine the inhibitory effect of the Fenton-process on the activated sludge mixture. The pollutant-removal efficiencies of the applied processes and their associated operating costs were determined. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Uisung; Han, Jeongwoo; Urgun Demirtas, Meltem

Wastewater treatment plants (WWTPs) produce sludge as a byproduct when they treat wastewater. In the United States, over 8 million dry tons of sludge are produced annually just from publicly owned WWTPs. Sludge is commonly treated in anaerobic digesters, which generate biogas; the biogas is then largely flared to reduce emissions of methane, a potent greenhouse gas. Because sludge is quite homogeneous and has a high energy content, it is a good potential feedstock for other conversion processes that make biofuels, bioproducts, and power. For example, biogas from anaerobic digesters can be used to generate renewable natural gas (RNG), whichmore » can be further processed to produce compressed natural gas (CNG) and liquefied natural gas (LNG). Sludge can be directly converted into hydrocarbon liquid fuels via thermochemical processes such as hydrothermal liquefaction (HTL). Currently, the environmental impacts of converting sludge into energy are largely unknown, and only a few studies have focused on the environmental impacts of RNG produced from existing anaerobic digesters. As biofuels from sludge generate high interest, however, existing anaerobic digesters could be upgraded to technology with more economic potential and more environmental benefits. The environmental impacts of using a different anaerobic digestion (AD) technology to convert sludge into energy have yet to be analyzed. In addition, no studies are available about the direct conversion of sludge into liquid fuels. In order to estimate the energy consumption and greenhouse gas (GHG) emissions impacts of these alternative pathways (sludge-to-RNG and sludge-to-liquid), this study performed a lifecycle analysis (LCA) using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model. The energy uses and GHG emissions associated with the RNG and hydrocarbon liquid are analyzed relative to the current typical sludge management case, which consists of a single-stage mesophilic digester with biogas flaring. Along with the alternative HTL process, four types of AD technologies with fuel production—single-stage mesophilic, mesophilic 2-stage, single-stage mesophilic with thermohydrolysis treatment, and mesophilicmesophilic acid/gas phase—are studied. Results show that the sludge-to-CNG pathway via AD and the sludge-to-liquid pathway via HTL reduce GHG emissions consumptions significantly. When we compare the GHG emissions of the alternative fuel production pathways to that of the counterfactual case in terms of the amount of sludge treated, reductions in GHG emissions are 39%–80% and 87% for alternative AD and HTL, respectively. Compared to petroleum gasoline and diesel GHG emission results in terms of MJ, the renewable CNG production pathway via AD and the renewable diesel production pathway via HTL reduce GHG emissions by 193% and 46%, respectively. These large reductions are mainly due to GHG credits from avoiding GHGs under the counterfactual scenario, and/or fertilizer displacement credits. Similarly, reductions in fossil fuel use for sludge-based fuels are huge. However, well-defined counterfactual scenarios are needed because the results of the study depend on the counterfactual scenario, which might vary over time.« less

The biodrying concept: an innovative technology creating energy from sewage sludge.

PubMed

Winkler, M-K H; Bennenbroek, M H; Horstink, F H; van Loosdrecht, M C M; van de Pol, G-J

2013-11-01

A full-scale biodrying installation was treating 150 kton (wet weight) of dewatered waste activated sludge per year. The waste was treated at thermophilic conditions (65-75 °C) in a 2-step forced aeration process reducing the total wet sludge weight by 73%. The final product had a high caloric value (7700-10,400 (kJ/kg)), allowing a combustion for energy generation in external facilities. The resulting product met the European microbial and heavy metal quality standards needed for an application as organic fertilizer. The facility used <0.5 MW of electricity and recovered 9.3 MW from biologically produced heat, which was internally used for the heating of office buildings. Produced ammonia, originating from the microbial conversion of organic matter, was recovered from the ventilated air in an acid gas scrubber as an ammonium sulphate solution 40% (w/w) (7.3 kton/year) and was sold as substitute for artificial fertilizers. The sustainability of this process is discussed relative to other sludge handling processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Treatment of winery wastewater in a conventional municipal activated sludge process: five years of experience.

PubMed

Bolzonella, D; Zanette, M; Battistoni, P; Cecchi, F

2007-01-01

A full-scale wastewater treatment plant where municipal and winery wastewaters were co-treated was studied for five years. The experimental results showed that suspended solids, COD, nitrogen and phosphorous were effectively removed both during the treatment of municipal wastewater and the cotreatment of municipal and winery wastewater. The sludge production increase from 4 tons to 5.5 tons per day during the harvesting and wine making period. In any case the specific sludge production was 0.2 kgMLVSS per kgCOD(removed) despite the organic loading increasing. About 70% of the COD was removed through respiration. Also the energy demand increased from 6,000 to 7,000 kWh per day. The estimated costs for the treatment of the winery wastewater was 0.2-0.3 Euros per m3 of treated wastewater. With reference to the process efficiency, the nitrogen removal was just 20%. The co-treatment of municipal and winery wastewater in conventional activated sludge processes can be a feasible solution for the treatment of these streams at relatively low costs.

Treatment of swine wastewater using chemically modified zeolite and bioflocculant from activated sludge.

PubMed

Guo, Junyuan; Yang, Chunping; Zeng, Guangming

2013-09-01

Sterilization, alkaline-thermal and acid-thermal treatments were applied to activated sludge and the pre-treated sludge was used as raw material for Rhodococcus R3 to produce polymeric substances. After 60 h of fermentation, bioflocculant of 2.7 and 4.2 g L(-1) were produced in sterilized and alkaline-thermal treated sludge as compared to that of 0.9 g L(-1) in acid-thermal treated sludge. Response surface methodology (RSM) was employed to optimize the treatment process of swine wastewater using the composite of bioflocculant and zeolite modified by calcining with MgO. The optimal flocculating conditions were bioflocculant of 24 mg L(-1), modified zeolite of 12 g L(-1), CaCl2 of 16 mg L(-1), pH of 8.3 and contact time of 55 min, and the corresponding removal rates of COD, ammonium and turbidity were 87.9%, 86.9%, and 94.8%. The use of the composite by RSM provides a feasible way to improve the pollutant removal efficiencies and recycle high-level of ammonium from wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Transesterification of Waste Activated Sludge for Biosolids Reduction and Biodiesel Production.

PubMed

Maeng, Min Ho; Cha, Daniel K

2018-02-01

  Transesterification of waste activated sludge (WAS) was evaluated as a cost-effective technique to reduce excess biosolids and recover biodiesel feedstock from activated sludge treatment processes. A laboratory-scale sequencing batch reactor (SBR) was operated with recycling transesterification-treated WAS back to the aeration basin. Seventy percent recycling of WAS resulted in a 48% reduction of excess biosolids in comparison with a conventional SBR, which was operated in parallel as the control SBR. Biodiesel recovery of 8.0% (dried weight basis) was achieved at an optimum transesterification condition using acidic methanol and xylene as cosolvent. Average effluent soluble chemical oxygen demand (COD) and total suspended solids (TSS) concentrations from the test SBR and control SBR were comparable, indicating that the recycling of transesterification-treated WAS did not have detrimental effect on the effluent quality. This study demonstrated that transesterification and recycling of WAS may be a feasible technique for reducing excess biosolids, while producing valuable biodiesel feedstock from the activated sludge process.

Improvement of anaerobic digestion of sewage sludge through microwave pre-treatment.

PubMed

Serrano, A; Siles, J A; Martín, M A; Chica, A F; Estévez-Pastor, F S; Toro-Baptista, E

2016-07-15

Sewage sludge generated in the activated sludge process is a polluting waste that must be treated adequately to avoid important environmental impacts. Traditional management methods, such as landfill disposal or incineration, are being ruled out due to the high content in heavy metal, pathogens, micropolluting compounds of the sewage sludge and the lack of use of resources. Anaerobic digestion could be an interesting treatment, but must be improved since the biomethanisation of sewage sludge entails low biodegradability and low methane production. A microwave pre-treatment at pilot scale is proposed to increase the organic matter solubilisation of sewage sludge and enhance the biomethanisation yield. The operational variables of microwave pre-treatment (power and specific energy applied) were optimised by analysing the physicochemical characteristics of sewage sludge (both total and soluble fraction) under different pre-treatment conditions. According to the variation in the sCOD and TN concentration, the optimal operation variables of the pre-treatment were fixed at 20,000 J/g TS and 700 W. A subsequent anaerobic digestion test was carried out with raw and pre-treated sewage sludge under different conditions (20,000 J/g TS and 700 W; 20,000 J/g TS and 400 W; and 30,000 J/g TS and 400 W). Although stability was maintained throughout the process, the enhancement in the total methane yield was not high (up to 17%). Nevertheless, very promising improvements were determined for the kinetics of the process, where the rG and the OLR increased by 43% and 39%, respectively, after carrying out a pre-treatment at 20,000 J/g TS and 700 W. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Industrial activated sludge exhibit unique bacterial community composition at high taxonomic ranks.

PubMed

Ibarbalz, Federico M; Figuerola, Eva L M; Erijman, Leonardo

2013-07-01

Biological degradation of domestic and industrial wastewater by activated sludge depends on a common process of separation of the diverse self-assembled and self-sustained microbial flocs from the treated wastewater. Previous surveys of bacterial communities indicated the presence of a common core of bacterial phyla in municipal activated sludge, an observation consistent with the concept of ecological coherence of high taxonomic ranks. The aim of this work was to test whether this critical feature brings about a common pattern of abundance distribution of high bacterial taxa in industrial and domestic activated sludge, and to relate the bacterial community structure of industrial activated sludge with relevant operational parameters. We have applied 454 pyrosequencing of 16S rRNA genes to evaluate bacterial communities in full-scale biological wastewater treatment plants sampled at different times, including seven systems treating wastewater from different industries and one plant that treats domestic wastewater, and compared our datasets with the data from municipal wastewater treatment plants obtained by three different laboratories. We observed that each industrial activated sludge system exhibited a unique bacterial community composition, which is clearly distinct from the common profile of bacterial phyla or classes observed in municipal plants. The influence of process parameters on the bacterial community structure was evaluated using constrained analysis of principal coordinates (CAP). Part of the differences in the bacterial community structure between industrial wastewater treatment systems were explained by dissolved oxygen and pH. Despite the ecological relevance of floc formation for the assembly of bacterial communities in activated sludge, the wastewater characteristics are likely to be the major determinant that drives bacterial composition at high taxonomic ranks. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

PubMed

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

2015-08-01

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

Electricity generation and in situ phosphate recovery from enhanced biological phosphorus removal sludge by electrodialysis membrane bioreactor.

PubMed

Geng, Yi-Kun; Wang, Yunkun; Pan, Xin-Rong; Sheng, Guo-Ping

2018-01-01

In this study, a novel electrodialysis membrane bioreactor was used for EBPR sludge treatment for energy and phosphorus resource recovery simultaneously. After 30days stable voltage outputting, the maximum power density reached 0.32W/m 3 . Over 90% of phosphorus in EBPR sludge was released while about 50% of phosphorus was concentrated to 4mmol/L as relatively pure phosphate solution. Nitrogen could be removed from EBPR sludge by desalination and denitrification processes. This study provides an optimized way treating sludge for energy production and in situ phosphorus recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alleviation of Cd toxicity by composted sewage sludge in Cd-treated Schmidt birch (Betula schmidtii) seedlings.

PubMed

Han, Sim-Hee; Lee, Jae-Cheon; Oh, Chang-Young; Kim, Pan-Gi

2006-10-01

We investigated alleviation of Cd toxicity and changes in the physiological characteristics of Betula schmidtii seedlings following application of composted sewage sludge to Cd-treated plants. Plants were grown under four test conditions: control, Cd treatment, sludge amendment, and Cd treatment with sludge amendment. B. schmidtii treated with Cd only accumulated the greatest amount of Cd in the leaves, but absorbed Cd was also highly concentrated in the roots. In contrast, Cd concentrations in the Cd and sludge amendment treated seedlings were the lowest in the roots. Since sludge amendment increased the growth of seedlings, it may have alleviated toxicity by dilution of Cd. Additionally, the absorbed Cd was more widely distributed since it was transported from the roots and accumulated in the stems and leaves of Cd and sludge treated plants. Cd treatment inhibited the growth and physiological functions of B. schmidtii seedlings, but sludge amendment compensated for these effects and improved growth and physiological functions in both Cd-treated and control plants. SOD activity in the leaves of seedlings was increased in the Cd-treated plants, but not in the Cd and sludge amendment treated seedlings. In conclusion, alleviation of Cd toxicity in response to sludge amendment may be related to a dilution effect, in which the Cd concentration in the tissues was effectively lowered by the improved growth performance of the seedlings.

Land Application of Treated Sewage Sludge in the United States: Regulatory Considerations for Risk Reduction and Determining Treatment Process Equivalency

EPA Science Inventory

In the United States, municipal wastewater includes discharges from households, commercial businesses and various industries. Microorganisms associated with these wastes can be concentrated in the solids (sludge) which are removed during treatment operations. Beneficial reuse a...

Fe-As sludge stability and effluent quality for a two-stage As-contaminated water treatment with Fe(II) and aeration.

PubMed

Zhuang, J Ming; Hobenshield, Evan; Walsh, Tony

2009-02-01

A two-stage (I and II) lab-scale treatment system has been studied for arsenic removal from water using Fe(II) and lignosulphonates with aeration. In stage I, using an Fe/As mole ratio of 1.5-2.5 at a pH of around 6.5-7.5, the dissolved arsenic can be reduced with Fe(II) oxidation-precipitation from an initial 72 mg L(-1) to < 2 mg L(-1). The generated sludge is entirely recycled to the second tank of stage II. In the first tank of stage II, the water is further treated with the same amount of Fe(II) as that used in stage I, in the presence of lignosulphonates and aeration. The air-oxidization of Fe(II) to Fe(III) is continued for about 30 minutes at a pH of around 7.0-8.0. The water output from the first tank is transferred to the second tank in which mixing under aeration occurs with the sludge recycled from stage I. Accordingly, the dissolved arsenic in the effluent is reduced to < 0.1 mg L(-1). The results show that this two-stage process can save more than 50% of total chemical costs, and reduce the amount of sludge by more than 50%, in comparison with the conventional Fe(III)/lime-treatment process. According to US EPA regulations, the final Fe-As sludge is classified as non-hazardous materials by the Toxicity Characteristic Leaching Procedure. But, the study shows that the instability of Fe-As sludge could be influenced by some factors, such as higher pH levels, a longer water-leaching time and larger water-leaching volume, leading to the liberation of more dissolvable As species. After being treated with Ligmet stabilizer, the Fe-As sludge showed an improved stability under varying pH conditions and large amounts of water leaching. The treated Fe-As sludge is suitable for landfill disposal.

Nonoxidative removal of organics in the activated sludge process

PubMed Central

Modin, Oskar; Persson, Frank; Wilén, Britt-Marie; Hermansson, Malte

2016-01-01

ABSTRACT The activated sludge process is commonly used to treat wastewater by aerobic oxidation of organic pollutants into carbon dioxide and water. However, several nonoxidative mechanisms can also contribute to removal of organics. Sorption onto activated sludge can remove a large fraction of the colloidal and particulate wastewater organics. Intracellular storage of, e.g., polyhydroxyalkanoates (PHA), triacylglycerides (TAG), or wax esters can convert wastewater organics into precursors for high-value products. Recently, several environmental, economic, and technological drivers have stimulated research on nonoxidative removal of organics for wastewater treatment. In this paper, we review these nonoxidative removal mechanisms as well as the existing and emerging process configurations that make use of them for wastewater treatment. Better utilization of nonoxidative processes in activated sludge could reduce the wasteful aerobic oxidation of organic compounds and lead to more resource-efficient wastewater treatment plants. PMID:27453679

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

PubMed

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.

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

PubMed Central

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

2017-01-01

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. PMID:29189754

Treatment options for low-level radiologically contaminated ORNL filtercake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hom-Ti; Bostick, W.D.

1996-04-01

Water softening sludge (>4000 stored low level contaminated drums; 600 drums per year) generated by the ORNL Process Waste Treatment Plant must be treated, stabilized, and placed in safe storage/disposal. The sludge is primarily CaCO{sub 3} and is contaminated by low levels of {sup 90}Sr and {sup 137}Cs. In this study, microwave sintering and calcination were evaluated for treating the sludge. The microwave melting experiments showed promise: volume reductions were significant (3-5X), and the waste form was durable with glass additives (LiOH, fly ash). A commercial vendor using surrogate has demonstrated a melt mineralization process that yields a dense monolithicmore » waste form with a volume reduction factor (VR) of 7.7. Calcination of the sludge at 850-900 C yielded a VR of 2.5. Compaction at 4500 psi increased the VR to 4.2, but the compressed form is not dimensionally stable. Addition of paraffin helped consolidate fines and yielded a VR of 3.5. In conclusion, microwave melting or another form of vitrification is likely to be the best method; however for immediate implementation, the calculation/compaction/waxing process is viable.« less

Pollutant removal characteristics of a two-influent-line BNR process performing denitrifying phosphorus removal: role of sludge recycling ratios.

PubMed

Liu, Hongbo; Leng, Feng; Chen, Piao; Kueppers, Stephan

2016-11-01

This paper studied denitrifying phosphorus removal of a novel two-line biological nutrient removal process treating low strength domestic wastewater under different sludge recycling ratios. Mass balance of intracellular compounds including polyhydroxyvalerate, polyhydroxybutyrate and glycogen was investigated together with total nitrogen (TN) and total phosphorus (TP). Results showed that sludge recycling ratios had a significant influence on the use of organics along bioreactors and 73.6% of the average removal efficiency was obtained when the influent chemical oxygen demand (COD) ranged from 175.9 mgL -1 to 189.9 mgL -1 . The process performed better under a sludge recycling ratio of 100% compared to 25% and 50% in terms of ammonia and COD removal rates. Overall, TN removal efficiency for 50% and 100% sludge recycling ratios were 56.4% and 61.9%, respectively, unlike the big gap for carbon utilization and the TP removal rates, indicating that the effect of sludge recycling ratio on the anaerobic compartments had been counteracted by change in the efficiency of other compartments. The higher ratio of sludge recycling was conducive to the removal of TN, not in favor of TP, and less influence on COD. Thus, 25% was considered to be the optimal sludge recycling ratio.

Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms

PubMed Central

Mantilla-Calderon, David

2017-01-01

ABSTRACT The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persister E. coli cells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes. PMID:28411227

Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

PubMed

Mantilla-Calderon, David; Hong, Pei-Ying

2017-07-01

The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persister E. coli cells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes. Copyright © 2017 Mantilla-Calderon and Hong.

Coupled heating/acidification pretreatment of chemical sludge for dewatering by using waste sulfuric acid at low temperature.

PubMed

Bian, Bo; Zhang, Limin; Zhang, Qin; Zhang, Shaopeng; Yang, Zhen; Yang, Weiben

2018-08-01

A cost-effective approach for pretreatment of chemical sludge for further dewatering, based on the idea of "using waste to treat waste", is provided. It is a coupled heating/acidification pretreatment method, where waste sulfuric acid is employed and relatively low temperatures (<100 °C) are applied. Effects of reaction time, temperature, and dosage of waste acid on dewatering performance (both dewatering speed and degree) are studied. Under the optimal conditions (reaction time: 30 min; temperature: 90 °C; waste acid dosage: 0.175 g/(g dried sludge)), the method of this work demonstrates three advantages compared to the conventional method using lime+polyacrylamide: lower moisture content of treated sludge; higher calorific value for incineration process; and lower cost. Detailed mechanism of the pretreatment for dewatering is investigated via characterizations and statistical analyses of various parameters, among which zeta potential, particle size, protein and polysaccharide contents, soluble chemical oxygen demand (SCOD), reduction of combined water and volatile suspended solid (VSS), are associated with dewatering performance. Both heating and acidification generate disintegration of cells in sludge, giving rise to two phenomena: more organic matters are released into solution and more bound water turns into free water. Meantime, the released organic polymers flocculate sludge particles, further accelerating the solid-liquid separation process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Landfill leachate sludge use as soil additive prior and after electrocoagulation treatment: A cytological assessment using CHO-k1 cells.

PubMed

Morozesk, M; Bonomo, M M; Rocha, L D; Duarte, I D; Zanezi, E R L; Jesus, H C; Fernandes, M N; Matsumoto, S T

2016-09-01

Electrocoagulation has recently attracted attention as a potential technique for treating toxic effluents due to its versatility and environmental compatibility, generating a residue chemically suitable to be used as a soil additive. In the present study, landfill leachate sludge hazardous effects were investigated prior and after electrocoagulation process using in vitro assays with the mammalian cells CHO-k1. An integrated strategy for risk assessment was used to correctly estimate the possible adverse landfill leachate sludge effects on human health and ecosystem. Electrocoagulation process proved to be an effective treatment due to possibility to improve effluent adverse characteristics and produce sludge with potential to be used as soil additive. Despite low cytoxicity, the residue presented genotoxic and mutagenic effects, indicating a capacity to induce genetic damages, probably due to induction of polyploidization process in cells. The observed effects demand an improvement of waste management methods for reduce negative risks of landfill leachate sludge application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Operation of an aquatic worm reactor suitable for sludge reduction at large scale.

PubMed

Hendrickx, Tim L G; Elissen, Hellen H J; Temmink, Hardy; Buisman, Cees J N

2011-10-15

Treatment of domestic waste water results in the production of waste sludge, which requires costly further processing. A biological method to reduce the amount of waste sludge and its volume is treatment in an aquatic worm reactor. The potential of such a worm reactor with the oligochaete Lumbriculus variegatus has been shown at small scale. For scaling up purposes, a new configuration of the reactor was designed, in which the worms were positioned horizontally in the carrier material. This was tested in a continuous experiment of 8 weeks where it treated all the waste sludge from a lab-scale activated sludge process. The results showed a higher worm growth rate compared to previous experiments with the old configuration, whilst nutrient release was similar. The new configuration has a low footprint and allows for easy aeration and faeces collection, thereby making it suitable for full scale application. Copyright © 2011 Elsevier Ltd. All rights reserved.

Improving bioelectricity generation and COD removal of sewage sludge in microbial desalination cell.

PubMed

Ebrahimi, Atieh; Yousefi Kebria, Daryoush; Darzi, Ghasem Najafpour

2018-05-01

Improving wastewater treatment process and water desalination are two important solutions for increasing the available supply of fresh water. Microbial desalination cells (MDCs) with common electrolytes display relatively low organic matter removal and high cost. In this study, sewage sludge was used as the substrate in the Microbial desalination cell (MDC) under three different initial salt concentrations (5, 20 and 35 g.L -1 ) and the maximum salt removal rates of 50.6%, 64% and 69.6% were obtained under batch condition, respectively. The MDC also produced the maximum power density of 47.1 W m -3 and the averaged chemical oxygen demand (COD) removal of 58.2 ± 0.89% when the initial COD was 6610 ± 83 mg L -1 . Employing treated sludge as catholyte enhanced COD removal and power density to 87.3% and 54.4 W m -3 , respectively, with counterbalancing pH variation in treated effluent. These promising results showed, for the first time, that the excess sewage sludge obtained from biological wastewater treatment plants could be successfully used as anolyte and catholyte in MDC, achieving organic matter biodegradation along with salt removal and energy production. In addition, using treated sludge as catholyte will improve the performance of MDC and introduce a more effective method for both sludge treatment and desalination.

Decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process.

PubMed

Mohd Nasir, Norlirubayah; Teo Ming, Ting; Ahmadun, Fakhru'l-Razi; Sobri, Shafreeza

2010-01-01

The research conducted a study on decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process. The purposes of this research are to remove pollutant through decomposition and to enhance the biodegradability of textile wastewater. The wastewater is treated using electron beam irradiation as a pre-treatment before undergo an activated sludge process. As a result, for non-irradiated wastewater, the COD removal was achieved to be between 70% and 79% after activated sludge process. The improvement of COD removal efficiency increased to 94% after irradiation of treated effluent at the dose of 50 kGy. Meanwhile, the BOD(5) removal efficiencies of non-irradiated and irradiated textile wastewater were reported to be between 80 and 87%, and 82 and 99.2%, respectively. The maximum BOD(5) removal efficiency was achieved at day 1 (HRT 5 days) of the process of an irradiated textile wastewater which is 99.2%. The biodegradability ratio of non-irradiated wastewater was reported to be between 0.34 and 0.61, while the value of biodegradability ratio of an irradiated wastewater increased to be between 0.87 and 0.96. The biodegradability enhancement of textile wastewater is increased with increasing the doses. Therefore, an electron beam radiation holds a greatest application of removing pollutants and also on enhancing the biodegradability of textile wastewater.

Beneficial Uses Program progress report, period ending December 31, 1976. [Gamma inactivation of microorganisms in sewage sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-03-01

Progress is reported on a comprehensive program to develop the necessary technologies for cost/beneficial uses of existing and future surplus radioactive materials. The major portion of the work was concentrated on the testing of the effectiveness of ..gamma.. sources for the processing of sewage sludge to inactivate enteric viruses and bacteria and the subsequent testing of the biological effects of the treated sludge when used as fertilizer or additives to animal feeds.

Biosynthesis of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by bacterial community from propylene oxide saponification wastewater residual sludge.

PubMed

Wang, Yiwei; Zhu, Ying; Gu, Pengfei; Li, Yumei; Fan, Xiangyu; Song, Dongxue; Ji, Yan; Li, Qiang

2017-05-01

The saponification wastewater from the process of propylene oxide (PO) production is contaminated with high chemical oxygen demand (COD) and chlorine contents. Although the activated sludge process could treat the PO saponification wastewater effectively, the residual sludge was difficult to be disposed properly. In this research, microbes in PO saponification wastewater residual sludge were acclimated to produce poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from volatile fatty acids. Through Miseq Illumina highthroughput sequencing, the bacterial community discrepancy between the original and the acclimated sludge samples were analyzed. The proportions of Bacillus, Acinetobacter, Brevundimonas and Pseudomonas, the potential PHBV-producers in the residual sludge, were all obviously increased. In the batch fermentation, the production of PHBV could achieve 4.262g/L at 300min, with the content increased from 0.04% to 23.67% of mixed liquor suspended solid (MLSS) in the acclimated sludge, and the COD of the PO saponification wastewater was also decreased in the fermentation. This work would provide an effective solution for the utilization of PO saponification wastewater residual sludge. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of acid detergent fiber in hydrothermally pretreated sewage sludge on anaerobic digestion process

NASA Astrophysics Data System (ADS)

Takasaki, Rikiya; Yuan, Lee Chang; Kamahara, Hirotsugu; Atsuta, Youichi; Daimon, Hiroyuki

2017-10-01

Hydrothermal treatment is one of the pre-treatment method for anaerobic digestion. The application of hydrothermal treatment to sewage sludge of wastewater treatment plant has been succeeded to enhance the biogas production. The purpose of this study is to quantitatively clarify the effect of hydrothermal treatment on anaerobic digestion process focusing on acid detergent fiber (ADF) in sewage sludge, which is low biodegradability. The hydrothermal treatment experiment was carried out for 15 minutes between 160 °C and 200 °C respectively. The ADF content was decreased after hydrothermal treatment compared with untreated sludge. However, ADF content was increased when raising the treatment temperature from 160 °C to 200 °C. During batch anaerobic digestion experiment, untreated and treated sludge were examined for 10 days under 38 °C, and all samples were fed once based on volatile solids of samples. From batch anaerobic digestion experiment, as ADF content in sewage sludge increased, the total biogas production decreased. It was found that ADF content in sewage sludge influence on anaerobic digestion. Therefore, ADF could be one of the indicator to evaluate the effect of hydrothermal treatment to sewage sludge on anaerobic digestion.

Qualitative and Quantitative Assessment of Sewage Sludge by Gamma Irradiation with Pasteurization as a Tool for Hygienization

NASA Astrophysics Data System (ADS)

Priyadarshini, J.; Roy, P. K.; Mazumdar, A.

2014-01-01

In this research work, management of sewage sludge disposal on agricultural soils is addressed. The increasing amount of sewage sludge and more legislative regulation of its disposal have stimulated the need for developing new technologies to recycle sewage sludge efficiently. The research was structured along two main avenues, namely, the efficacy of the irradiation process for removing enteric pathogenic microorganisms and the potential of irradiated sludge as a soil amendment. This study investigated how application of irradiation with heat treatment reduced pathogens in sewage sludge. Raw and pasteurised Sewage sludge was treated at different dose treatment of 1.5, 3 and 5 kilogray (kGy) gamma irradiation individually and for 3 kGy sufficiency was achieved. Decrease in irradiation dose from 5 to 3 kGy was observed for pasteurised sludge resulting in saving of radiation energy. The presence of heavy metals in untreated sewage sludge has raised concerns, which decreases after irradiation.

Combining high-rate aerobic wastewater treatment with anaerobic digestion of waste activated sludge at a pulp and paper mill.

PubMed

Magnusson, Björn; Ekstrand, Eva-Maria; Karlsson, Anna; Ejlertsson, Jörgen

2018-05-01

The activated sludge process within the pulp and paper industry is generally run to minimize the production of waste activated sludge (WAS), leading to high electricity costs from aeration and relatively large basin volumes. In this study, a pilot-scale activated sludge process was run to evaluate the concept of treating the wastewater at high rate with a low sludge age. Two 150 L containers were used, one for aeration and one for sedimentation and sludge return. The hydraulic retention time was decreased from 24 hours to 7 hours, and the sludge age was lowered from 12 days to 2-4 days. The methane potential of the WAS was evaluated using batch tests, as well as continuous anaerobic digestion (AD) in 4 L reactors in mesophilic and thermophilic conditions. Wastewater treatment capacity was increased almost four-fold at maintained degradation efficiency. The lower sludge age greatly improved the methane potential of the WAS in batch tests, reaching 170 NmL CH 4 /g VS at a sludge age of 2 days. In addition, the continuous AD showed a higher methane production at thermophilic conditions. Thus, the combination of high-rate wastewater treatment and AD of WAS is a promising option for the pulp and paper industry.

Organic matter and heavy metals content modeling in sewage sludge treated with reed bed system

NASA Astrophysics Data System (ADS)

Boruszko, Dariusz; Dąbrowski, Wojciech; Malinowski, Paweł

2017-11-01

The long process of sludge stabilization (7-15 years) remarkably reduces the organic matter content and causes the process of sludge humifaction. This paper presents the results of using low-cost methods of sludge treatment in the wastewater treatment plant located in Zambrow, Podlaskie Province. The results of studies on the organic matter and heavy metals content in sewage sludge after treatment in a reed bed system are presented. The aim of the research was to evaluate and model organic matter and heavy metals concentrations during sewage stabilization in reed bed lagoons. The lowest concentration, below 1.3 mg/kg DM of the examined seven heavy metals was mercury (Hg). The highest concentration, exceeding 1300 mg/kg DM was zinc (Zn). The obtained results for the heavy metals in sewage sludge from the reed bed lagoons in Zambrow show that the average content of the analyzed heavy metals is approximately 1620 mg/kg DM. The results of the study demonstrate a high efficiency of low-cost methods used in Zambrów WWTP in terms of the quality of the processed sludge. Sewage sludge from the lowest layer of the reed lagoon (12-14 years of dewatering and transformation) is characterized by the lowest organic matter and heavy metals content. The higher a sediment layer lies, i.e. the shorter the time of processing, the higher is the heavy metals content. This indicates a great role of reeds in the accumulation of these compounds.

Effects of chemical sludge disintegration on the performances of wastewater treatment by membrane bioreactor.

PubMed

Oh, Young-Khee; Lee, Ki-Ryong; Ko, Kwang-Baik; Yeom, Ick-Tae

2007-06-01

A new wastewater treatment process combining a membrane bioreactor (MBR) with chemical sludge disintegration was tested in bench scale experiments. In particular, the effects of the disintegration treatment on the excess sludge production in MBR were investigated. Two MBRs were operated. In one reactor, a part of the mixed liquor was treated with NaOH and ozone gas consecutively and was returned to the bioreactor. The flow rate of the sludge disintegration stream was 1.5% of the influent flow rate. During the 200 days of operation, the MLSS level in the bioreactor with the disintegration treatment was maintained relatively constant at the range of 10,000-11,000 mg/L while it increased steadily up to 25,000 mg/L in the absence of the treatment. In the MBR with the sludge disintegration, relatively constant transmembrane pressures (TMPs) could be maintained for more than 6 months while the MBR without disintegration showed an abrupt increase of TMP in the later phase of the operation. In conclusion, a complete control of excess sludge production in the membrane-coupled bioreactor was possible without significant deterioration of the treated water quality and membrane performances.

Effect of humic acid in leachate on specific methanogenic activity of anaerobic granular sludge.

PubMed

Guo, Mengfei; Xian, Ping; Yang, Longhui; Liu, Xi; Zhan, Longhui; Bu, Guanghui

2015-01-01

In order to find out the effects of humic acid (HA) in anaerobic-treated landfill leachate on granular sludge, the anaerobic biodegradability of HA as well as the influences of HA on the total cumulative methane production, the anaerobic methanization process and the specific methanogenic activity (SMA) of granular sludge are studied in this paper. Experimental results show that as a non-biodegradable organic pollutant, HA is also difficult to be decomposed by microbes in the anaerobic reaction process. Presence of HA and changes in the concentration have no significant influences on the total cumulative methane production and the anaerobic methanization process of granular sludge. Besides, the total cumulative methane production cannot reflect the inhibition of toxics on the methanogenic activity of granular sludge on the premise of sufficient reaction time. Results also show that HA plays a promoting role on SMA of granular sludge. Without buffering agent the SMA value increased by 19.2% on average due to the buffering and regulating ability of HA, while with buffering agent the SMA value increased by 5.4% on average due to the retaining effect of HA on the morphology of the sludge particles. However, in the presence of leachate the SMA value decreased by 27.6% on average, because the toxic effect of the toxics in the leachate on granular sludge is much larger than the promoting effect of HA.

Preliminary Study of Thermal Treatment of Coke Wastewater Sludge Using Plasma Torch

NASA Astrophysics Data System (ADS)

Li, Mingshu; Li, Shengli; Sun, Demao; Liu, Xin; Feng, Qiubao

2016-10-01

Thermal plasma was applied for the treatment of coke wastewater sludge derived from the steel industry in order to investigate the feasibility of the safe treatment and energy recovery of the sludge. A 30 kW plasma torch system was applied to study the vitrification and gas production of coke wastewater sludge. Toxicity leaching results indicated that the sludge treated via the thermal plasma process converted into a vitrified slag which resisted the leaching of heavy metals. CO2 was utilized as working gas to study the production and heat energy of the syngas. The heating value of the gas products by thermal plasma achieved 8.43 kJ/L, indicating the further utilization of the gas products. Considering the utilization of the syngas and recovery heat from the gas products, the estimated treatment cost of coke wastewater sludge via plasma torch was about 0.98 CNY/kg sludge in the experiment. By preliminary economic analysis, the dehydration cost takes an important part of the total sludge treatment cost. The treatment cost of the coke wastewater sludge with 50 wt.% moisture was calculated to be about 1.45 CNY/kg sludge dry basis. The treatment cost of the coke wastewater sludge could be effectively controlled by decreasing the water content of the sludge. These findings suggest that an economic dewatering pretreatment method could be combined to cut the total treatment cost in an actual treatment process.

Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater.

PubMed

Moretti, Paul; Choubert, Jean-Marc; Canler, Jean-Pierre; Buffière, Pierre; Pétrimaux, Olivier; Lessard, Paul

2018-02-01

The integrated fixed-film activated sludge (IFAS) process is being increasingly used to enhance nitrogen removal for former activated sludge systems. The aim of this work is to evaluate a numerical model of a new nitrifying/denitrifying IFAS configuration. It consists of two carrier-free reactors (anoxic and aerobic) and one IFAS reactor with a filling ratio of 43% of carriers, followed by a clarifier. Simulations were carried out with GPS-X involving the nitrification reaction combined with a 1D heterogeneous biofilm model, including attachment/detachment processes. An original iterative calibration protocol was created comprising four steps and nine actions. Experimental campaigns were carried out to collect data on the pilot in operation, specifically for modelling purpose. The model used was able to predict properly the variations of the activated sludge (bulk) and the biofilm masses, the nitrification rates of both the activated sludge and the biofilm, and the nitrogen concentration in the effluent for short (4-10 days) and long (300 days) simulation runs. A calibrated parameter set is proposed (biokinetics, detachment, diffusion) related to the activated sludge, the biofilm and the effluent variables to enhance the model prediction on hourly and daily data sets.

Nitrogen removal from the saline sludge liquor by electrochemical denitrification.

PubMed

Xie, Z M; Li, X Y; Chan, K Y

2006-01-01

Sludge liquor from the sludge dewatering process has a high ammonia content. In the present study, a lab-scale electrochemical (EC) system with a pair of Ti electrode plates was used for treating the sludge centrate liquor of digested wastewater sludge with a NH4(+) - N content of around 500 mg/L. The sludge liquor had a high salinity due to seawater being used for toilet flushing in Hong Kong. The results show that the EC process is highly effective for denitrification of the saline sludge liquor. Complete nitrogen removal could be achieved within 1 hr or so. The rate of EC denitrification increased with the current intensity applied. The best current efficiency for nitrogen removal was obtained for a gap distance between the electrodes at 8 mm. Electro-chlorination was considered to be the major mechanism of EC denitrification. The formation of chlorination by-products (CBPs) appeared to be minimal with the total trihalomethanes (THM) detected at a level of 300 microg/L or lower. The power consumption for EC denitrification was around 23 kWh/kg N. Additional electro-flocculation with a pair of iron needle electrodes could enhance the flocculation and subsequent sedimentation of colloidal organics in the sludge liquor, increasing the organic removal from less than 30% to more than 70%. Therefore, the EC process including both electro-denitrification and electro-flocculation can be developed as the most cost-effective method for treatment of the saline sludge liquor.

Characterization of water treatment sludge and its reuse as coagulant.

PubMed

Ahmad, Tarique; Ahmad, Kafeel; Ahad, Abdul; Alam, Mehtab

2016-11-01

Coagulation-flocculation process results in the generation of large volume of waste or residue, known as water treatment sludge (WTS), in the purification of surface water for potable supplies. Sustainable management of the inevitable waste requires careful attention from the plant operators and sludge managers. In this study, WTS produced with the optimum alum dose of 30 ml/L at the laboratory scale has been treated with sulphuric acid to bring forth a product known as sludge reagent product (SRP). The performance of SRP is evaluated for its efficiency in removing the colloidal suspensions from the Yamuna river water over wide pH range of 2-13. 1% sludge acidified with sulphuric acid of normality 2.5 at the rate of 0.05 ml/ml sludge has been observed as the optimum condition for preparing SRP from WTS. The percentage turbidity removal is greater at higher pH value and increases with increasing the dosage of SRP. The optimum SRP dosage of 8 ml/L in the pH range of 6-8 performed well in removing the colloidal suspension and other impurities from the Yamuna water. The quality of treated water met the prescribed standards for most of the quality parameters. Thus, SRP has the potential to substitute the conventional coagulants partially or completely in the water treatment process, depending on the quality needed at the users end. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of steroid estrogens from municipal wastewater in a pilot scale expanded granular sludge blanket reactor and anaerobic membrane bioreactor

PubMed Central

Ito, Ayumi; Mensah, Lawson; Cartmell, Elise; Lester, John N.

2016-01-01

Anaerobic treatment of municipal wastewater offers the prospect of a new paradigm by reducing aeration costs and minimizing sludge production. It has been successfully applied in warm climates, but does not always achieve the desired outcomes in temperate climates at the biochemical oxygen demand (BOD) values of municipal crude wastewater. Recently the concept of ‘fortification' has been proposed to increase organic strength and has been demonstrated at the laboratory and pilot scale treating municipal wastewater at temperatures of 10–17°C. The process treats a proportion of the flow anaerobically by combining it with primary sludge from the residual flow and then polishing it to a high effluent standard aerobically. Energy consumption is reduced as is sludge production. However, no new treatment process is viable if it only addresses the problems of traditional pollutants (suspended solids – SS, BOD, nitrogen – N and phosphorus – P); it must also treat hazardous substances. This study compared three potential municipal anaerobic treatment regimes, crude wastewater in an expanded granular sludge blanket (EGSB) reactor, fortified crude wastewater in an EGSB and crude wastewater in an anaerobic membrane bioreactor. The benefits of fortification were demonstrated for the removal of SS, BOD, N and P. These three systems were further challenged with the removal of steroid estrogens at environmental concentrations from natural indigenous sources. All three systems removed these compounds to a significant degree, confirming that estrogen removal is not restricted to highly aerobic autotrophs, or aerobic heterotrophs, but is also a faculty of anaerobic bacteria. PMID:26212345

Evaluation Of Sludge Heel Dissolution Efficiency With Oxalic Acid Cleaning At Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sudduth, Christie; Vitali, Jason; Keefer, Mark

The chemical cleaning process baseline strategy at the Savannah River Site was revised to improve efficiency during future execution of the process based on lessons learned during previous bulk oxalic acid cleaning activities and to account for operational constraints imposed by safety basis requirements. These improvements were also intended to transcend the difficulties that arise from waste removal in higher rheological yield stress sludge tanks. Tank 12 implemented this improved strategy and the bulk oxalic acid cleaning efforts concluded in July 2013. The Tank 12 radiological removal results were similar to previous bulk oxalic acid cleaning campaigns despite the factmore » that Tank 12 contained higher rheological yield stress sludge that would make removal more difficult than the sludge treated in previous cleaning campaigns. No appreciable oxalate precipitation occurred during the cleaning process in Tank 12 compared to previous campaigns, which aided in the net volume reduction of 75-80%. Overall, the controls established for Tank 12 provide a template for an improved cleaning process.« less

Land application technique for the treatment and disposal of sewage sludge.

PubMed

Zain, S M; Basri, H; Suja, F; Jaafar, O

2002-01-01

Some of the major concerns when applying sewage sludge to land include the potential effect on pH and cation exchange capacity; the mobility and the accumulation of heavy metals in sludge treated soil; the potential of applying too much nutrients and the problems associated with odors and insects. The main objective of this study is to identify the effects of sewage sludge application on the physical and chemical properties of sludge treated soil. Sewage sludge was applied to soil at various rates ranging from 0 L/m2 to 341 L/m2. In order to simulate the natural environment, the study was carried out at a pilot treatment site (5.2 m x 6.7 m) in an open area, covered with transparent roofing material to allow natural sunlight to pass through. Simulated rain was applied by means of a sprinkler system. Data obtained from sludge treated soil showed that the pH values decreased when the application rates were increased and the application period prolonged. The effect of sewage sludge on cation exchange capacity was not so clear; the values obtained for every application rate of sewage sludge did not indicate any consistent behaviour. The mobility of heavy metals in soils treated with sludge were described by observing the changes in the concentration of the heavy metals. The study showed that Cd has the highest mobility in sludge treated soil followed by Cu, Cr, Zn, Ni and Pb.

Moringa oleifera-mediated coagulation of textile wastewater and its biodegradation using novel consortium-BBA grown on agricultural waste substratum.

PubMed

Bedekar, Priyanka A; Bhalkar, Bhumika N; Patil, Swapnil M; Govindwar, Sanjay P

2016-10-01

Generation of secondary sludge is a major concern of textile dye removal by coagulation process. Combinatorial coagulation-biodegradation treatment system has been found efficient in degradation of coagulated textile dye sludge. Moringa oleifera seed powder (700 mg L -1 ) was able to coagulate textile dyestuff from real textile wastewater with 98 % color removal. Novel consortium-BBA was found to decolorize coagulated dye sludge. Parameters that significantly affect coagulation process were optimized using response surface methodology. The bench-scale stirred tank reactor (50-L capacity) designed with optimized parameters for coagulation process could efficiently remove 98, 89, 78, and 67 % of American Dye Manufacturer's Institute (ADMI) in four repetitive cycles, respectively. Solid-state fermentation composting reactor designed to treat coagulated dye sludge showed 96 % removal of dye within 10 days. Coagulation of dyes from textile wastewater and degradation of coagulated dye sludge were confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. Cell morphology assay, comet assay, and phytotoxicity confirmed the formation of less toxic products after coagulation and degradation mechanism.

Comparison of laboratory-scale thermophilic biofilm and activated sludge processes integrated with a mesophilic activated sludge process.

PubMed

Suvilampi, J; Lehtomäki, A; Rintala, J

2003-07-01

A combined thermophilic-mesophilic wastewater treatment was studied using a laboratory-scale thermophilic activated sludge process (ASP) followed by mesophilic ASP or a thermophilic suspended carrier biofilm process (SCBP) followed by mesophilic ASP, both systems treating diluted molasses (dilution factor 1:500 corresponding GF/A-filtered COD (COD(filt)) of 1900+/-190 mgl(-1)). With hydraulic retention times (HRTs) of 12-18 h the thermophilic ASP and thermophilic SCBP removed 60+/-13% and 62+/-7% of COD(filt), respectively, with HRT of 8 h the removals were 48+/-1% and 69+/-4%. The sludge volume index (SVI) was notably lower in the thermophilic SCBP (measured from suspended sludge) than in the thermophilic ASP. Under the lowest HRT the mesophilic ASP gave better performance (as SVI, COD(filt), and COD(tot) removals) after the thermophilic SCBP than after the thermophilic ASP. Measured sludge yields were low (less than 0.1 kg suspended solids (SS) kg COD(filt removed)(-1)) in all processes. Both thermophilic treatments removed 80-85% of soluble COD (COD(sol)) whereas suspended COD (COD(susp)) and colloidal COD (COD(col)) were increased. Both mesophilic post-treatments removed all COD(col) and most of the COD(susp) from the thermophilic effluents. In conclusion, combined thermophilic-mesophilic treatment appeared to be easily operable and produced high effluent quality.

Enhancing the functional and economical efficiency of a novel combined thermo chemical disperser disintegration of waste activated sludge for biogas production.

PubMed

Kavitha, S; Jayashree, C; Adish Kumar, S; Kaliappan, S; Rajesh Banu, J

2014-12-01

In this investigation, an effort was made to pretreat surplus waste activated sludge (WAS) inexpensively by a novel combined process involving thermo chemical disperser pretreatment. This pretreatment was found to be efficient at a specific energy (SE) consumption of 3360.94 kJ/kg TS, with the chemical oxygen demand (COD) solubilization of 20%. This was comparatively higher than thermo chemically treated sludge where the solubilization was found to be 15.5% at a specific energy consumption of 10,330 kJ/kg TS respectively. Higher production of volatile fatty acids (VFA) (675 mg/L) in anaerobic fermentation of pretreated WAS indicates better hydrolysis performance. The biogas production potential of sludge pretreated through this combined technique was found to be 0.455 (L/gVS) and comparatively higher than thermo chemically pretreated sludge. Economic investigation provides 90% net energy savings in this combined pretreatment. Therefore, this combined process was considered to be potentially effective and economical in sludge disintegration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hybrid life-cycle environmental and cost inventory of sewage sludge treatment and end-use scenarios: a case study from China.

PubMed

Murray, Ashley; Horvath, Arpad; Nelson, Kara L

2008-05-01

Sewage sludge management poses environmental, economic, and political challenges for wastewater treatment plants and municipalities around the globe. To facilitate more informed and sustainable decision making, this study used life-cycle inventory (LCI) to expand upon previous process-based LCIs of sewage sludge treatmenttechnologies. Additionally, the study evaluated an array of productive end-use options for treated sewage sludge, such as fertilizer and as an input into construction materials, to determine how the sustainability of traditional manufacturing processes changes with sludge as a replacement for other raw inputs. The inclusion of the life-cycle of necessary inputs (such as lime) used in sludge treatment significantly impacts the sustainability profiles of different treatment and end-use schemes. Overall, anaerobic digestion is generally the optimal treatment technology whereas incineration, particularly if coal-fired, is the most environmentally and economically costly. With respect to sludge end use, offsets are greatest for the use of sludge as fertilizer, but all of the productive uses of sludge can improve the sustainability of conventional manufacturing practices. The results are intended to help inform and guide decisions about sludge handling for existing wastewater treatment plants and those that are still in the planning phase in cities around the world. Although additional factors must be considered when selecting a sludge treatment and end-use scheme, this study highlights how a systems approach to planning can contribute significantly to improving overall environmental sustainability.

Oxygen transfer and uptake, nutrient removal, and energy footprint of parallel full-scale IFAS and activated sludge processes.

PubMed

Rosso, Diego; Lothman, Sarah E; Jeung, Matthew K; Pitt, Paul; Gellner, W James; Stone, Alan L; Howard, Don

2011-11-15

Integrated fixed-film activated sludge (IFAS) processes are becoming more popular for both secondary and sidestream treatment in wastewater facilities. These processes are a combination of biofilm reactors and activated sludge processes, achieved by introducing and retaining biofilm carrier media in activated sludge reactors. A full-scale train of three IFAS reactors equipped with AnoxKaldnes media and coarse-bubble aeration was tested using off-gas analysis. This was operated independently in parallel to an existing full-scale activated sludge process. Both processes achieved the same percent removal of COD and ammonia, despite the double oxygen demand on the IFAS reactors. In order to prevent kinetic limitations associated with DO diffusional gradients through the IFAS biofilm, this systems was operated at an elevated dissolved oxygen concentration, in line with the manufacturer's recommendation. Also, to avoid media coalescence on the reactor surface and promote biofilm contact with the substrate, high mixing requirements are specified. Therefore, the air flux in the IFAS reactors was much higher than that of the parallel activated sludge reactors. However, the standardized oxygen transfer efficiency in process water was almost same for both processes. In theory, when the oxygen transfer efficiency is the same, the air used per unit load removed should be the same. However, due to the high DO and mixing requirements, the IFAS reactors were characterized by elevated air flux and air use per unit load treated. This directly reflected in the relative energy footprint for aeration, which in this case was much higher for the IFAS system than activated sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of operational conditions on sludge degradation and organic acids formation in low-critical wet air oxidation.

PubMed

Chung, Jinwook; Lee, Mikyung; Ahn, Jaehwan; Bae, Wookeun; Lee, Yong-Woo; Shim, Hojae

2009-02-15

Wet air oxidation processes are to treat highly concentrated organic compounds including refractory materials, sludge, and night soil, and usually operated at supercritical water conditions of high temperature and pressure. In this study, the effects of operational conditions including temperature, pressure, and oxidant dose on sludge degradation and conversion into subsequent intermediates such as organic acids were investigated at low critical wet oxidation conditions. The reaction time and temperature in the wet air oxidation process was shown an important factor affecting the liquefaction of volatile solids, with more significant effect on the thermal hydrolysis reaction rather than the oxidation reaction. The degradation efficiency of sludge and the formation of organic acids were improved with longer reaction time and higher reaction temperature. For the sludge reduction and the organic acids formation under the wet air oxidation, the optimal conditions for reaction temperature, time, pressure, and oxidant dose were shown approximately 240 degrees C, 30min, 60atm, and 2.0L/min, respectively.

40 CFR 257.3-6 - Disease.

Code of Federal Regulations, 2010 CFR

2010-07-01

... this section. (1) Sewage sludge that is applied to the land surface or is incorporated into the soil is... incorporated into the soil are treated by a Process to Significantly Reduce Pathogens (as listed in appendix II... surface or are incorporated into the soil are treated by a Process to Further Reduce Pathogens, prior to...

40 CFR 257.3-6 - Disease.

Code of Federal Regulations, 2012 CFR

2012-07-01

... this section. (1) Sewage sludge that is applied to the land surface or is incorporated into the soil is... incorporated into the soil are treated by a Process to Significantly Reduce Pathogens (as listed in appendix II... surface or are incorporated into the soil are treated by a Process to Further Reduce Pathogens, prior to...

40 CFR 257.3-6 - Disease.

Code of Federal Regulations, 2014 CFR

2014-07-01

... this section. (1) Sewage sludge that is applied to the land surface or is incorporated into the soil is... incorporated into the soil are treated by a Process to Significantly Reduce Pathogens (as listed in appendix II... surface or are incorporated into the soil are treated by a Process to Further Reduce Pathogens, prior to...

40 CFR 257.3-6 - Disease.

Code of Federal Regulations, 2013 CFR

2013-07-01

... this section. (1) Sewage sludge that is applied to the land surface or is incorporated into the soil is... incorporated into the soil are treated by a Process to Significantly Reduce Pathogens (as listed in appendix II... surface or are incorporated into the soil are treated by a Process to Further Reduce Pathogens, prior to...

Anaerobic treatment of sludge from a nitrification-denitrification landfill leachate plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maranon, E.; Castrillon, L.; Fernandez, Y.

2006-07-01

The viability of anaerobic digestion of sludge from a MSW landfill leachate treatment plant, with COD values ranging between 15,000 and 19,400 mg O{sub 2} dm{sup -3}, in an upflow anaerobic sludge blanket reactor was studied. The reactor employed had a useful capacity of 9 l, operating at mesophilic temperature. Start-up of the reactor was carried out in different steps, beginning with diluted sludge and progressively increasing the amount of sludge fed into the reactor. The study was carried out over a period of 7 months. Different amounts of methanol were added to the feed, ranging between 6.75 and 1more » cm{sup 3} dm{sup -3} of feed in order to favour the growth of methanogenic flora. The achieved biodegradation of the sludge using an upflow anaerobic sludge blanket Reactor was very high for an HRT of 9 days, obtaining decreases in COD of 84-87% by the end of the process. Purging of the digested sludge represented {approx}16% of the volume of the treated sludge.« less

Biosorption of Cu(II) by powdered anaerobic granular sludge from aqueous medium.

PubMed

Zhou, Xu; Chen, Chuan; Wang, Aijie; Jiang, Guangming; Liu, Lihong; Xu, Xijun; Yuan, Ye; Lee, Duu-Jung; Ren, Nanqi

2013-01-01

Copper(II) biosorption processes by two pre-treated powdered anaerobic granular sludges (PAGS) (original sludges were methanogenic anaerobic granules and denitrifying sulfide removal (DSR) anaerobic granules) were investigated through batch tests. Factors affecting the biosorption process, such as pH, temperature and initial copper concentrations, were examined. Also, the physico-chemical characteristics of the anaerobic sludge were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy image, surface area and elemental analysis. A second-order kinetic model was applied to describe the biosorption process, and the model could fit the biosorption process. The Freundlich model was used for describing the adsorption equilibrium data and could fit the equilibrium data well. It was found that the methanogenic PAGS was more effective in Copper(II) biosorption process than the DSR PAGS, whose maximum biosorption capacity was 39.6% lower. The mechanisms of the biosorption capacities for different PAGS were discussed, and the conclusion suggested that the environment and biochemical reactions during the growth of biomass may have affected the structure of the PAGS. The methanogenic PAGS had larger specific surface area and more biosorption capacity than the DSR PAGS.

Aerobic granulation in a modified oxidation ditch with an adjustable volume intraclarifier.

PubMed

Li, Jun; Cai, Ang; Wang, Miao; Ding, Libin; Ni, Yongjiong

2014-04-01

A modified oxidation ditch (MOD) with an adjustable volume intraclarifier was proposed and used to achieve aerobic sludge granulation in continuous flow process. This MOD with working volume of 60L treated onsite wastewater from a town. Excellent aerobic granules with mean diameter of 600μm and sludge volume index (SVI) of 44mL/g were obtained in 120day. Bacterial community analysis revealed that most species from seed sludge were preserved in both MOD and granule SBR (G-SBR) except bacteria (Bacteroidetes) might be easily washed out during granulation. Some different bacterial communities were found in sludges from sequencing batch and continuous flow reactors. Presence of metal ions and inorganics in raw wastewater had positive effect on granule formation, but an adjustable volume intraclarifier for controlling selection pressure and deleting return sludge pump played a key role in aerobic sludge granulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Helminth prevalence in a waste-water plant at El Rosal, Cundinamarca].

PubMed

Ortiz, Carolina; López, Myriam C; Rivas, Favio A

2012-01-01

Assessing helminth egg prevalence in sludge and raw and treated wastewater from a wastewater treatment system located in the village of El Rosal, Cundinamarca. 30 wastewater and 10 sludge samples from the El Rosal plant were taken during a 10-week period. The sludge and water samples were processed according to the Bailinger and the official Mexican standard methodology, respectively. Egg viability was determined by the method described by Victórica & Galván and the Mexican official standard. Descriptive statistics were used for analysing data. 100 % of the untreated wastewater samples showed the presence of eggs and at least one viable helminth egg/litre was found in 90 % of them. 90 % of the treated wastewater samples were positive for the presence of eggs, finding that 70 % had at least one viable egg. All raw wastewater samples being dumped directly into the stream were positive for helminths; the same situation was found at the time of the viability test. All sludge samples were positive for helminths, finding that 100 % of these had at least one viable egg. Using this water for crop irrigation and using the sludge as fertiliser is a potential risk for public health. The sludge can only be used in forestry activities, as long as it does not come into contact with humans.

Concomitant degradation of bisphenol A during ultrasonication and Fenton oxidation and production of biofertilizer from wastewater sludge.

PubMed

Mohapatra, D P; Brar, S K; Tyagi, R D; Surampalli, R Y

2011-09-01

Degradation of bisphenol A (BPA), an endocrine disruptor, from wastewater sludge (WWS) has attracted great interest recently. In the present study, the effects of different pre-treatment methods, including ultrasonication (US), Fenton's oxidation (FO) and ferro-sonication (FS) was assessed in terms of increase in solubilization of WWS and simultaneous degradation of BPA. Among US, FO and FS pre-treatment, higher suspended solids (SS), volatile suspended solids (VSS), chemical oxygen demand (COD) and soluble organic carbon (SOC) solubilization (39.7%, 51.2%, 64.5% and 17.6%, respectively) was observed during a ferro-sonication pre-treatment process carried out for 180 min, resulting in higher degradation of BPA (82.7%). In addition, the effect of rheological parameters (viscosity and particle size) and zeta potential on the degradation of BPA in raw and different pre-treated sludges were also investigated. The results showed that a decrease in viscosity and particle size and an increase in zeta potential resulted in higher degradation of BPA. BPA degradation by laccases produced by Sinorhizobium meliloti in raw and pre-treated sludge was also determined. Higher activity of laccases (207.9 U L(-1)) was observed in ferro-sonicated pre-treated sludge (180 min ultrasonic time), resulting in higher removal of BPA (0.083 μg g(-1)), suggesting concomitant biological degradation of BPA. Copyright © 2011 Elsevier B.V. All rights reserved.

Cost-performance analysis of nutrient removal in a full-scale oxidation ditch process based on kinetic modeling.

PubMed

Li, Zheng; Qi, Rong; Wang, Bo; Zou, Zhe; Wei, Guohong; Yang, Min

2013-01-01

A full-scale oxidation ditch process for treating sewage was simulated with the ASM2d model and optimized for minimal cost with acceptable performance in terms of ammonium and phosphorus removal. A unified index was introduced by integrating operational costs (aeration energy and sludge production) with effluent violations for performance evaluation. Scenario analysis showed that, in comparison with the baseline (all of the 9 aerators activated), the strategy of activating 5 aerators could save aeration energy significantly with an ammonium violation below 10%. Sludge discharge scenario analysis showed that a sludge discharge flow of 250-300 m3/day (solid retention time (SRT), 13-15 days) was appropriate for the enhancement of phosphorus removal without excessive sludge production. The proposed optimal control strategy was: activating 5 rotating disks operated with a mode of "111100100" ("1" represents activation and "0" represents inactivation) for aeration and sludge discharge flow of 200 m3/day (SRT, 19 days). Compared with the baseline, this strategy could achieve ammonium violation below 10% and TP violation below 30% with substantial reduction of aeration energy cost (46%) and minimal increment of sludge production (< 2%). This study provides a useful approach for the optimization of process operation and control.

Comparing the effects of three pre-treatment disintegration techniques on aerobic sludge digestion: biodegradability enhancement and microbial community monitoring by PCR-DGGE.

PubMed

Jaziri, Kais; Casellas, Magali; Dagot, Christophe

2012-06-01

The objectives of this work were to compare and investigate the effect of three activated sludge disintegration processes before aerobic sludge digestion on 1) aerobic biodegradability enhancement and 2) microbial community evolution using the polymerase chain reaction-denaturant gel gradient electrophoresis (PCR-DGGE) technique. The comparison of three disintegration processes: thermal treatment (95 degrees C, 2h), sonication (100,000 kJ/kgTS) and ozonation (0.108 g O3/gTS) showed that the disintegration processes acted differently according to the composition of the soluble phase and to the DNA damage. Thermal treatment led to significant protein solubilization and to DNA modification. Sonication and ozonation resulted in similar soluble phase compositions and did not lead to any DNA modifications. During activated sludge aerobic digestion, intrinsic biodegradability enhancement was observed for thermal and ozone activated sludge pre-treatments. The analysis of the DGGE patterns at the end of aerobic digestion showed that population diversity was affected by both the aerobic digestion and the pre-treatment. The dissimilarity percentages measured at the end of aerobic digestion in the control sample and in the treated sludge were equal to 22, 25 and 20% for thermal treatment, sonication and ozonation respectively. This study indicated that PCR-DGGE could be a useful tool for the comparison of disintegration processes before and after aerobic digestion.

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

PubMed

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

2015-01-01

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

Relationship between enhanced dewaterability and structural properties of hydrothermal sludge after hydrothermal treatment of excess sludge.

PubMed

Wang, Liping; Li, Aimin; Chang, Yuzhi

2017-04-01

Hydrothermal treatment is an effective method to enhance the deep dewaterability of excess sludge with low energy consumption. In this study, an insight into the relationship between enhanced dewaterability and structural properties of the produced hydrothermal sludge was presented, aiming at better understanding the effect of hydrothermal process on excess sludge dewatering performance. The results indicated that hydrothermal effect induced the transformation of surface water to interstitial and free water by lowering the binding strength between adjacent water and solid particles and that free water became the main form for moisture existence in hydrothermal sludge as temperature was higher than 180 °C. Increase in temperature of hydrothermal treatment generated a significant size reduction of sludge flocs but treated sludge with a higher rigidity, which not only strengthened the network of hydrothermal sludge but also destroyed the binding of EPS with water. Hydrothermal process caused crevice and pore structures of excess sludge to disappear gradually, which was a main driving force of water removal as temperature was below 150 °C. With the temperature of hydrothermal treatment exceeding 180 °C, the morphology of hydrothermal sludge became rough which linked closely to the solid precipitation of condensation polymerization, and further became smooth at higher temperature (210 °C) due to the coal-like structures with higher aromaticities, indicating that hydrothermal reaction pathways began to play a main role in enhanced dewaterability. Hydrothermal treatment led to more alkyl and aromatic carbon, but lower O-alkyl, carboxyl and carbonyl carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Delisting petition for 300-M saltstone (treated F006 sludge) from the 300-M liquid effluent treatment facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-04-04

This petition seeks exclusion for stabilized and solidified sludge material generated by treatment of wastewater from the 300-M aluminum forming and metal finishing processes. The waste contains both hazardous and radioactive components and is classified as a mixed waste. The objective of this petition is to demonstrate that the stabilized sludge material (saltstone), when properly disposed, will not exceed the health-based standards for the hazardous constituents. This petition contains sampling and analytical data which justify the request for exclusion. The results show that when the data are applied to the EPA Vertical and Horizontal Spread (VHS) Model, health-based standards formore » all hazardous waste constituents will not be exceeded during worst case operating and environmental conditions. Disposal of the stabilized sludge material in concrete vaults will meet the requirements pertaining to Waste Management Activities for Groundwater Protection at the Savannah River Site in Aiken, S.C. Documents set forth performance objectives and disposal options for low-level radioactive waste disposal. Concrete vaults specified for disposal of 300-M saltstone (treated F006 sludge) assure that these performance objectives will be met.« less

THE HYDROTHERMAL REACTIONS OF MONOSODIUM TITANATE, CRYSTALLINE SILICOTITANATE AND SLUDGE IN THE MODULAR SALT PROCESS: A LITERATURE SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fondeur, F.; Pennebaker, F.; Fink, S.

2010-11-11

The use of crystalline silicotitanate (CST) is proposed for an at-tank process to treat High Level Waste at the Savannah River Site. The proposed configuration includes deployment of ion exchange columns suspended in the risers of existing tanks to process salt waste without building a new facility. The CST is available in an engineered form, designated as IE-911-CW, from UOP. Prior data indicates CST has a proclivity to agglomerate from deposits of silica rich compounds present in the alkaline waste solutions. This report documents the prior literature and provides guidance for the design and operations that include CST to mitigatemore » that risk. The proposed operation will also add monosodium titanate (MST) to the supernate of the tank prior to the ion exchange operation to remove strontium and select alpha-emitting actinides. The cesium loaded CST is ground and then passed forward to the sludge washing tank as feed to the Defense Waste Processing Facility (DWPF). Similarly, the MST will be transferred to the sludge washing tank. Sludge processing includes the potential to leach aluminum from the solids at elevated temperature (e.g., 65 C) using concentrated (3M) sodium hydroxide solutions. Prior literature indicates that both CST and MST will agglomerate and form higher yield stress slurries with exposure to elevated temperatures. This report assessed that data and provides guidance on minimizing the impact of CST and MST on sludge transfer and aluminum leaching sludge.« less

Environmental assessment of different dewatering and drying methods on the basis of life cycle assessment.

PubMed

Stefaniak, J; Zelazna, A; Pawłowski, A

2014-01-01

Sewage sludge is an inevitable product of wastewater treatment in municipal wastewater plants and its amount has increased dramatically due to the growing number of sewage systems users. This sludge needs to be adequately treated in order to decrease its hazardous properties and any negative influence on the environment. In this paper, gate to gate analysis, on the basis of life cycle assessment (LCA), was carried out in order to compare the environmental impact of alternative ways of sludge processing employing a dewatering press and three different kinds of dryers - belt dryer, container dryer and batch dryer. SimaPro 7.2 software and Ecoinvent 2.2 database were used to estimate the carbon footprint and energy balance of these processes. The main energy consumption in the scenarios analyzed is caused by the drying process. The solution based on application of the batch dryer allows a saving of 39.6% of energy compared with the most energy-consuming solution using a belt dryer. Sludge processing using belt and container dryers cause greater environmental burdens.

Application of a membrane bioreactor for winery wastewater treatment.

PubMed

Bolzonella, D; Fatone, F; Pavan, P; Cecchi, F

2010-01-01

Winery wastewaters are variable in nature and are hard to treat by means of the conventional activated sludge process because of the high organic loading associated with their production, especially during vintage. To face this situation, recently, membrane bioreactors have been widely applied to treat winery wastewaters. In this study, a full-scale membrane bioreactor treated some 110 m(3)/d of wastewater and organic loadings up to 1,600 kg COD per day. The average removal efficiency was 95% while the corresponding sludge yield was only 0.1 kg MLVSS per kg COD removed, as usual for these wastewaters. A detailed analysis of energy consumption showed specific energy demands of 2.0-3.6 kWh/m(3) of treated wastewater or 1 kWh per kg of COD removed.

Anaerobic bioremediation of hexavalent uranium in groundwater by reductive precipitation with methanogenic granular sludge.

PubMed

Tapia-Rodriguez, Aida; Luna-Velasco, Antonia; Field, Jim A; Sierra-Alvarez, Reyes

2010-04-01

Uranium has been responsible for extensive contamination of groundwater due to releases from mill tailings and other uranium processing waste. Past evidence has confirmed that certain bacteria can enzymatically reduce soluble hexavalent uranium (U(VI)) to insoluble tetravalent uranium (U(IV)) under anaerobic conditions in the presence of appropriate electron donors. This paper focuses on the evaluation of anaerobic granular sludge as a source of inoculum for the bioremediation of uranium in water. Batch experiments were performed with several methanogenic anaerobic granular sludge samples and different electron donors. Abiotic controls consisting of heat-killed inoculum and non-inoculated treatments confirmed the biological removal process. In this study, unadapted anaerobic granular sludge immediately reduced U(VI), suggesting an intrinsic capacity of the sludge to support this process. The high biodiversity of anaerobic granular sludge most likely accounts for the presence of specific microorganisms capable of reducing U(VI). Oxidation by O(2) was shown to resolubilize the uranium. This observation combined with X-ray diffraction evidence of uraninite confirmed that the removal during anaerobic treatment was due to reductive precipitation. The anaerobic removal activity could be sustained after several respikes of U(VI). The U(VI) removal was feasible without addition of electron donors, indicating that the decay of endogenous biomass substrates was contributing electron equivalents to the process. Addition of electron donors, such as H(2) stimulated the removal of U(VI) to varying degrees. The stimulation was greater in sludge samples with lower endogenous substrate levels. The present work reveals the potential application of anaerobic granular sludge for continuous bioremediation schemes to treat uranium-contaminated water. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Treating Sludges

ERIC Educational Resources Information Center

Josephson, Julian

1978-01-01

Discussed are some of the ways to handle municipal and industrial wastewater treatment sludge presented at the 1978 American Chemical Society meeting. Suggestions include removing toxic materials, recovering metals, and disposing treated sewage sludge onto farm land. Arguments for and against land use are also given. (MA)

K-Basins Sludge Treatment and Packaging at the Hanford Site - 13585

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogwell, Thomas W.; Honeyman, James O.; Stegen, Gary

Highly radioactive sludge resulting from the storage of degraded spent nuclear fuel has been consolidated in Engineered Containers (ECs) in the 105-K West Storage Basin located on the Hanford site near the Columbia River in Washington State. CH2M Hill Plateau Remediation Company (CHPRC) is proceeding with a project to retrieve the sludge, place it in Sludge Transport and Storage Containers (STSCs) and store those filled containers within the T Plant Canyon facility on the Hanford Site Central Plateau (Phase 1). Retrieval and transfer of the sludge material will enable removal of the 105-K West Basin and allow remediation of themore » subsurface contamination plumes under the basin. The U.S. Department of Energy (DOE) plans to treat and dispose of this K Basins sludge (Phase 2) as Remote Handled Transuranic Waste (RH TRU) at the Waste Isolation Pilot Plant (WIPP) located in New Mexico. The K Basin sludge currently contains uranium metal which reacts with water present in the stored slurry, generating hydrogen and other byproducts. The established transportation and disposal requirements require the transformation of the K Basins sludge to a chemically stable, liquid-free, packaged waste form. The Treatment and Packaging Project includes removal of the containerised sludge from T Plant, the treatment of the sludge as required, and packaging of all the sludge into a form that is certifiable for transportation to and disposal at WIPP. Completion of this scope will require construction and operation of a Sludge Treatment and Packaging Facility (STPF), which could be either a completely new facility or a modification of an existing Hanford Site facility. A Technology Evaluation and Alternatives Analysis (TEAA) for the STP Phase 2 was completed in 2011. A Request for Technology Information (RFI) had been issued in October 2009 to solicit candidate technologies for use in Phase 2. The RFI also included a preliminary definition of Phase 2 functions and requirements. Potentially applicable technologies were identified through a commercial procurement process, technical workshops, and review of the numerous previous sludge treatment technology studies. The identified technology approaches were screened using the criteria established in the Decision Plan, and focused bench top feasibility testing was conducted. Engineering evaluations of the costs, schedules, and technical maturity were developed and evaluated. Recommendations were developed based on technical evaluations. The criteria used in the evaluation process were as follows: (1) Safety, (2) Regulatory/stakeholder acceptance, (3) Technical maturity, (4) Operability and maintainability, (5) Life cycle cost and schedule, (6) Potential for beneficial integration with ongoing STP-Phase 1 activities, and (7) Integration with Site-wide RH-TRU processing/packaging, planning, schedule, and approach. The TEAA recommended Warm Water Oxidation (WWO) as the baseline treatment technology and two risk reduction enhancement options for further consideration during development of the process - size reduction and chemical oxidation (Fenton's reagent). The enhancement options would potentially allow a useful reduction in the total operating time required to process the K Basins sludge. The U.S. Department of Energy's Richland Field Office (DOE-RL) has approved this recommended technical approach. The baseline process can be broken down into the following main process steps: (1) STSC transfer from T Plant to the Sludge Treatment and Packaging Facility (STPF). (2) Retrieval of sludge from the STSCs and transfer to the Receipt and Reaction Tank (RRT). (3) Preparation for immobilization by oxidation using heated water (i.e., WWO) for those batches that require it and concentration by evaporating water at about atmospheric pressure in the RRT. (4) Immobilization by using additives to eliminate free liquids and packaging of the treated sludge into drums. (5) Inspection and handling of the filled drums prior to transfer to a separate storage and shipping facility. (6) Handling of vapor, condensate, and other waste streams generated by the process. Each of these steps is discussed in the paper, together with the current state of progress in developing the technology and requirements for continued development. A schematic of the recommended baseline WWO treatment process is given below. (authors)« less

Effect of electron beam irradiation on bacterial and Ascaris ova loads and volatile organic compounds in municipal sewage sludge

NASA Astrophysics Data System (ADS)

Engohang-Ndong, Jean; Uribe, R. M.; Gregory, Roger; Gangoda, Mahinda; Nickelsen, Mike G.; Loar, Philip

2015-07-01

Wastewater treatment plants produce large amounts of biosolids that can be utilized for land applications. However, prior to their use, these biosolids must be treated to eliminate risks of infections and to reduce upsetting odors. In this study, microbiological and chemical analyzes were performed before and after treatment of sewage sludge with 3 MeV of an electron beam accelerator in a pilot processing plant. Thus, we determined that dose 4.5 kGy was required to reduce fecal coliform counts to safe levels for land applications of sludge while, 14.5 kGy was necessary to decrease Ascaris ova counts to safe levels. Furthermore, at low doses, electron beam irradiation showed little effect on the concentrations of volatile organic compounds, while some increase were recorded at high doses. The concentration of dimethyl sulfide was reduced by 50-70% at irradiation doses of 25.7 kGy and 30.7 kGy respectively. By contrast, electron beam irradiation increased dimethyl disulfide concentrations. We also showed that electron beam treatment was less energy-consuming with shorter processing times than conventional techniques used to decontaminate sludge. Hence opening new avenues for large urban agglomerations to save money and time when treating biosolids for land application.

Phosphorous removal from aqueous solution can be enhanced through the calcination of lime sludge.

PubMed

Bal Krishna, K C; Niaz, Mohamed R; Sarker, Dipok C; Jansen, Troy

2017-09-15

Water treatment plants generate an enormous amount of the sludge which is normally treated as waste. In the recent past, many investigations have been focused on developing an economical adsorbent using water treatment sludge to remove phosphorous (P) from aqueous solutions. However, the great extents of the studies have been limited in the use of alum- and iron-based sludges. This study, therefore, investigated the P removal performance of the calcined lime sludge. Calcined lime sludge at 700 °C significantly enhanced the P removal efficiency whereas marginal improvement was noted when the sludge calcined at 400 °C was tested. With increase P removal efficiency, final pH values of the solution also significantly increased. P removal efficiency of the calcined sludge decreased with increasing the initial P concentrations. However, the removal efficiency could be improved by increasing the weight of the sludge. Further analysis demonstrated that P removal trend followed both pseudo-second order and diffusion-chemisorption kinetics signifying the P removal is potentially due to a multi-mechanistic reaction in which, the process is controlled by intra-particle diffusion followed by chemisorptions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vitrification as an alternative to landfilling of tannery sewage sludge.

PubMed

Celary, Piotr; Sobik-Szołtysek, Jolanta

2014-12-01

Due to high content of heavy metals such as chromium, tannery sewage sludge is a material which is difficult to be biologically treated as it is in the case of organic waste. Consequently, a common practice in managing tannery sewage sludge is landfilling. This poses a potential threat to both soil and water environments and it additionally generates costs of construction of landfills that meet specific environment protection requirements. Vitrification of this kind of sewage sludge with the addition of mineral wastes can represent an alternative to landfilling. The aim of this study was to investigate the possibility of obtaining an environmentally safe product by means of vitrification of tannery sewage sludge from a flotation wastewater treatment process and chemical precipitation in order to address the upcoming issue of dealing with sewage sludge from the tannery industry which will be prohibited to be landfilled in Poland after 2016. The focus was set on determining mixtures of tannery sewage sludge with additives which would result in the lowest possible heavy metal leaching levels and highest hardness rating of the products obtained from their vitrification. The plasma vitrification process was carried out for mixtures with various amounts of additives depending on the type of sewage sludge used. Only the materials of waste character were used as additives. One finding of the study was an optimum content of mineral additives in vitrified mixture of 30% v/v waste molding sands with 20% v/v carbonate flotation waste from the zinc and lead industry for the formulations with flotation sewage sludge, and 45% v/v and 5% v/v, respectively, for precipitation sewage sludge. These combinations allowed for obtaining products with negligible heavy metal leaching levels and hardness similar to commercial glass, which suggests they could be potentially used as construction aggregate substitutes. Incineration of sewage sludge before the vitrification process lead to increased hardness of the vitrificates and reduced leaching of some heavy metals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Model evaluation of temperature dependency for carbon and nitrogen removal in a full-scale activated sludge plant treating leather-tanning wastewater.

PubMed

Görgün, Erdem; Insel, Güçlü; Artan, Nazik; Orhon, Derin

2007-05-01

Organic carbon and nitrogen removal performance of a full-scale activated sludge plant treating pre-settled leather tanning wastewater was evaluated under dynamic process temperatures. Emphasis was placed upon observed nitrogen removal depicting a highly variable magnitude with changing process temperatures. As the plant was not specifically designed for this purpose, observed nitrogen removal could be largely attributed to simultaneous nitrification and denitrification presumably occurring at increased process temperatures (T>25 degrees C) and resulting low dissolved oxygen levels (DO<0.5 mgO2/L). Model evaluation using long-term data revealed that the yearly performance of activated sludge reactor could be successfully calibrated by means of temperature dependent parameters associated with nitrification, hydrolysis, ammonification and endogenous decay parameters. In this context, the Arrhenius coefficients of (i) for the maximum autotrophic growth rate, [image omitted]A, (ii) maximum hydrolysis rate, khs and (iii) endogenous heterotrophic decay rate, bH were found to be 1.045, 1.070 and 1.035, respectively. The ammonification rate (ka) defining the degradation of soluble organic nitrogen could not be characterized however via an Arrhenius-type equation.

Feasibility of the UV/AA process as a pretreatment approach for bioremediation of dye-laden wastewater.

PubMed

Yang, Minghui; Wu, Bingdang; Li, Qiuhao; Xiong, Xiaofeng; Zhang, Haoran; Tian, Yu; Xie, Jiawen; Huang, Ping; Tan, Suo; Wang, Guodong; Zhang, Li; Zhang, Shujuan

2018-03-01

Biodegradability and toxicity are two important indexes in considering the feasibility of a chemical process for environmental remediation. The acetylacetone (AA) mediated photochemical process has been proven as an efficient approach for dye decolorization. Both AA and its photochemical degradation products had a high bioavailability. However, the biocompatibility and ecotoxicology of the UV/AA treated solutions are unclear yet. In the present work, we evaluated the biocompatibility and toxicity of the UV/AA treated solutions at both biochemical and organismal levels. The biodegradability of the treated solution was evaluated with the ratio of 5-d biological oxygen demand (BOD 5 ) to chemical oxygen demand (COD) and a 28-d activated sludge assay (Zahn-Wellens tests). The UV/AA process significantly improved the biodegradability of the tested dye solutions. Toxicity was assessed with responses of microorganisms (microbes in activated sludge and Daphnia magna) and plants (bok choy, rice seed, and Arabidopsis thaliana) to the treated solutions, which showed that the toxicity of the UV/AA treated solutions was lower or comparable to that of the UV/H 2 O 2 counterparts. The results are helpful for us to determine whether the UV/AA process is applicable to certain wastewaters and how the UV/AA process could be effectively combined into a sequential chemical-biological water treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Farmers' attitude toward treated sludge use in the villages of West Bank, Palestine.

PubMed

Rashid, Md M; Kattou'a, Mary G; Al-Khatib, Issam A; Sato, Chikashi

2017-07-01

An application of treated sewage sludge on agricultural land has been widely accepted, as this method is simple and economical for disposal of wastewater residues. When applied properly on an agricultural land, sludge can replenish organic matter and nutrients in soil. Although sewage sludge has been used in agriculture in many parts of the world, its acceptability varies with different cultures and beliefs among farmers. Farmers' concerns on sludge use are primarily due to its anthropogenic origin, pollutants that it carries, a general perception of sewage being dirty, and its offensive odor. This paper aims to investigate farmers' perceptions on land application of treated sewage sludge on their farm. This study targeted two farming communities, namely, Anza and Beit Dajan villages, located in Jenin and Nablus districts in the West Bank, Palestine. In this study, a sample of 106 farmers were randomly selected and surveyed through a mixture of structured and open-ended questions. Results indicated that, overall, farmers have positive perceptions on land application of sludge. A majority of the farmers are in favor of the concept of sludge use when a planned wastewater treatment plant is constructed and it becomes operational. Results also indicate that a majority of the farmers are in favor of using sludge for fertilizing fruit trees, rather than growing vegetables and other plants in a greenhouse, and that many of them have knowledge of sludge properties and advantages and disadvantages of sludge use in agriculture. Despite the positive perceptions by the majority of farmers, a small fraction of the farmers are in disfavor of the use of sludge for the following reasons: psychological and social concerns, potential health risks, and their religious beliefs. Results further suggest that the land application of treated sewage sludge can be accepted by more farmers if the consumers are willing to buy agricultural products fertilized by sludge, sludge meets the public health requirements, and sludge is available at low costs. To improve farmers' perceptions on the land application of sludge, several measures are recommended.

Effect of Recycle Sludge on Anaerobic Digestion of Palm Oil Mill Effluent in A Thermophilic Continuous Digester

NASA Astrophysics Data System (ADS)

Irvan; Trisakti, B.; Tomiuchi, Y.; Harahap, U.; Daimon, H.

2017-06-01

The objective of this research is to maintain short retention time and high degradation of palm oil mill effluent (POME) to biogas by applying recycle sludge. Fresh POME from Rambutan Mill without further treatment was used as feed. Two lab-scale digesters supported from Metawater Co. Ltd. have been applied to treat POME at thermophilic (55°C) condition. Both digesters were operated under intermittent operation mode. Experiments were performed in two methods: with and without recycle sludge. Hydraulic retention time (HRT) of both methods was maintained at 6 days, while sludge retention time (SRT) was maintained at various days. The result showed that by extending SRT in return sludge process where 25% of digested slurry recycled to the digester, improvement of volatile solid (VS) decomposition was obtained around 84% at HRT of 6 days and SRT of 21 days. Then, chemical oxygen demand (COD) removal efficiency could be reached until 85% by using recycle sludge.

Persistence of pathogenic prion protein during simulated wastewater treatment processes

USGS Publications Warehouse

Hinckley, G.T.; Johnson, C.J.; Jacobson, K.H.; Bartholomay, C.; Mcmahon, K.D.; McKenzie, D.; Aiken, Judd M.; Pedersen, J.A.

2008-01-01

Transmissible spongiform encephalopathies (TSEs, prion diseases) are a class of fatal neurodegenerative diseases affecting a variety of mammalian species including humans. A misfolded form of the prion protein (PrP TSE) is the major, if not sole, component of the infectious agent. Prions are highly resistant to degradation and to many disinfection procedures suggesting that, if prions enter wastewater treatment systems through sewers and/or septic systems (e.g., from slaughterhouses, necropsy laboratories, rural meat processors, private game dressing) or through leachate from landfills that have received TSE-contaminated material, prions could survive conventional wastewater treatment Here, we report the results of experiments examining the partitioning and persistence of PrPTSE during simulated wastewater treatment processes including activated and mesophilic anaerobic sludge digestion. Incubation with activated sludge did not result in significant PrPTSE degradation. PrPTSE and prion infectivity partitioned strongly to activated sludge solids and are expected to enter biosolids treatment processes. A large fraction of PrPTSE survived simulated mesophilic anaerobic sludge digestion. The small reduction in recoverable PrPTSE after 20-d anaerobic sludge digestion appeared attributable to a combination of declining extractability with time and microbial degradation. Our results suggest that if prions were to enter municipal wastewater treatment systems, most would partition to activated sludge solids, survive mesophilic anaerobic digestion, and be present in treated biosolids. ?? 2008 American Chemical Society.

[Treatment of Flue Gas from Sludge Drying Process by A Thermophilic Biofilter].

PubMed

Chen, Wen-he; Deng, Ming-jia; Luo, Hui; Ding, Wen-iie; Li, Lin; Lin, Jian; Liu, Jun-xin

2016-01-15

A thermophilic biofilter was employed to treat the flue gas generated from sludge drying process, and the performance in both the start period and the stationary phase was studied under the gas flow rate of 2 700-3 100 m3 x h(-1) and retention time of 21.88-25.10 s. The results showed that the thermophilic biofilter could effectively treat gases containing sulfur dioxide, ammonia and volatile organic compounds (VOC). The removal efficiencies could reach 100%, 93.61% and 87.01%, respectively. Microbial analysis indicated that most of the population belonged to thermophilic bacteria. Paenibacillus sp., Chelatococcus sp., Bacillus sp., Clostridium thermosuccinogenes, Pseudoxanthomonas sp. and Geobacillus debilis which were abundant in the thermophilic biofilter, had the abilities of denitrification, desulfurization and degradation of volatile organic compounds.

Microbial population dynamics during startup of a full-scale anaerobic digester treating industrial food waste in Kyoto eco-energy project.

PubMed

Ike, Michihiko; Inoue, Daisuke; Miyano, Tomoki; Liu, Tong Tong; Sei, Kazunari; Soda, Satoshi; Kadoshin, Shiro

2010-06-01

The microbial community in a full-scale anaerobic digester (2300m3) treating industrial food waste in the Kyoto Eco-Energy Project was analyzed using terminal restriction fragment length polymorphism for eubacterial and archaeal 16S rRNA genes. Both thermophilic and mesophilic sludge of treated swine waste were seeded to the digestion tank. During the 150-day startup period, coffee grounds as a main food waste, along with potato, kelp and boiled beans, tofu, bean curd lees, and deep-fried bean curd were fed to the digestion process step-by-step (max. 40t/d). Finally, the methane yield reached 360m3/t-feed with 40days' retention time, although temporary accumulation of propionate was observed. Eubacterial communities that formed in the thermophilic digestion tank differed greatly from both thermophilic and mesophilic types of seed sludge. Results suggest that the Actinomyces/Thermomonospora and Ralstonia/Shewanella were contributors for hydrolyzation and degradation of food waste into volatile fatty acids. Acetate-utilizing methanogens, Methanosaeta, were dominant in seed sludges of both types, but they decreased drastically during processing in the digestion tank. Methanosarcina and Methanobrevibacter/Methanobacterium were, respectively, possible main contributors for methane production from acetate and H2 plus CO2. Copyright 2010 Elsevier Ltd. All rights reserved.

SURVEY OF SOLIDIFICATION/STABILIZATION TECHNOLOGY FOR HAZARDOUS INDUSTRIAL WASTES

EPA Science Inventory

Stabilization/solidification or fixation is a process for treating industrial solid wastes (primarily sludges) that contain hazardous constituents to prevent dissolution and loss of toxic materials into the environment. Most of these treatment processes are designed to produce a ...

Sewage sludge drying method combining pressurized electro-osmotic dewatering with subsequent bio-drying.

PubMed

Li, Qian; Lu, Xuebin; Guo, Haigang; Yang, Zengjun; Li, Yingte; Zhi, Suli; Zhang, Keqiang

2018-04-30

In this study, pressurized electro-osmotic dewatering (PEOD) as a pretreatment process, instead of the conventional practice of adding bulking agents, for sewage sludge bio-drying was proposed. Initially, various parameters were optimized for obtaining dewatered sewage sludge (DSS), treated by an efficient, quick, and energy-saving PEOD process. The results show that the moisture content (MC) of sewage sludge could decrease from 83.41% to 60.0% within 7.5 min in the optimum conditions of the PEOD process. Subsequently, two DSS bio-drying tests were carried out to investigate the effects of inoculation. The highest temperature (68.1 °C) was obtained for T2 (inoculation), which was 3.6 °C higher than that for T1 (non- inoculation). The MC accumulative removal rate for T1 (41.49%) was slightly less than that for T2 (44.60%). Lastly, the volatile solid degradation dynamics model parameters were measured. The degradation rate constants (k) for T1 and T2 were 0.00501 and 0.00498, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

THE CONTRIBUTION OF AZO DYES TO THE MUTAGENIC ACTIVITY OF THE CRISTAIS RIVER

EPA Science Inventory

To verify if compounds within the discharge of a dye processing plant were contributing to the mutagenicity repeatedly found in the Cristais River, Sao Paulo, Brazil, we chemically characterized the treated industrial effluent, raw and treated water, and the sludge produced by a ...

AZO DYES ARE MAJOR CONTRIBUTORS TO THE MUTAGENIC ACTIVITY DETECTED IN THE CRISTAIS RIVER WATERS

EPA Science Inventory

To determine if compounds from a dye processing plant were contributing to the mutagenicity repeatedly found in the Cristais River, Sao Paulo, Brazil, we chemically characterized the treated industrial effluent, raw and treated water, and the sludge produced by a Drinking Water T...

Virus elimination in activated sludge systems: from batch tests to mathematical modeling.

PubMed

Haun, Emma; Ulbricht, Katharina; Nogueira, Regina; Rosenwinkel, Karl-Heinz

2014-01-01

A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus concentration in batch tests and in a municipal full-scale WWTP under steady-state and dynamic conditions. The experimental and modeling results suggest that both adsorption and inactivation processes, modeled as reversible first-order reactions, contribute to virus elimination in activated sludge systems. The model should be a useful tool to estimate the number of viruses entering water bodies from the discharge of treated effluents.

Influence of extracellular polymeric substances (EPS) treated by combined ultrasound pretreatment and chemical re-flocculation on water treatment sludge settling performance.

PubMed

Chen, Wei; Gao, Xiaohong; Xu, Hang; Cai, Yan; Cui, Jianfeng

2017-03-01

Extracellular polymeric substances (EPS) are high molecular weight polymers and play a significant role in floc stability, floc size, bioflocculation and sludge settleability. The destruction and reconstruction of EPS improve the performance of solid-water separation processes. In this study, the influence of combined ultrasound pretreatment and chemical re-flocculation on the spatial distribution and composition of EPS was examined. Settleability efficiency demonstrated that the optimal operating condition was an ultrasound pretreatment time of 15 min at pH 6. Sludge particles were greatly disintegrated and the protein-like substances were converted into smaller molecules after ultrasound treatment, and pH had important effects on solubilization and degradation of protein-like substances. The flocs of sludge water after addition of polyacrylamide were larger in size and denser in structure than those resulting from addition of polyaluminium chloride. However, polyaluminium chloride had a better capacity for degrading EPS, especially at a dosage of 1.2 g/g total suspended solids. The results of this research show that the combination of ultrasonication and chemical re-flocculation is effective in treating sludge water from a drinking water treatment plant. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of the fine fraction of the argon oxygen decarburization with lance (AOD-L) sludge generated by the stainless steelmaking industry.

PubMed

Majuste, Daniel; Mansur, Marcelo Borges

2008-05-01

The argon oxygen decarburization with lance (AOD-L) sludge generated by the stainless steelmaking industry is a hazardous waste due to the presence of chromium. While its coarse fraction is usually recycled into the own industrial process, the fine fraction is normally disposed in landfills. Techniques such as briquetting or magnetic separation were found to be inadequate to treat it for reuse purposes. So, in this work, the fine fraction of the AOD-L sludge was characterized aiming to find alternative methods to treat it. This sludge consists of a fine powder (mean diameter of 1 microm) containing 34 +/- 2% (w/w) of iron, 10.2 +/- 0.9% (w/w) of chromium and 1.4 +/- 0.1% (w/w) of nickel. The main crystalline phases identified in this study were chromite (FeCr(2)O(4)), magnetite (Fe(3)O(4)), hematite (Fe(2)O(3)) and calcite (CaCO(3)). In the digestion tests, the addition of HClO(4) has favored the dissolution of chromite which is a very stable oxide in aqueous media. Nickel was found in very fine particles, probably in the metallic form or associated with iron and oxygen. The sludge was classified as hazardous waste, so its disposal in landfills should be avoided.

Performance evaluation of a large sewage treatment plant in Brazil, consisting of an upflow anaerobic sludge blanket reactor followed by activated sludge.

PubMed

Saliba, Pollyane Diniz; von Sperling, Marcos

2017-10-01

The objective of this study was to evaluate the behaviour of a system comprising an upflow anaerobic sludge blanket reactor followed by activated sludge to treat domestic sewage. The Betim Central sewage treatment plant, Brazil, was designed to treat a mean influent flow of 514 L/s. The study consisted of statistical treatment of monitoring data from the treatment plant covering a period of 4 years. This work presents the concentrations and removal efficiencies of the main constituents in each stage of the treatment process, and a mass balance of chemical oxygen demand (COD) and nitrogen. The results highlight the good overall performance of the system, with high mean removal efficiencies: BOD (biochemical oxygen demand) (94%), COD (91%), ammonia (72%) and total suspended solids (92%). As expected, this system was not effective for the removal of nutrients, since it was not designed for this purpose. The removal of Escherichia coli (99.83%) was higher than expected. There was no apparent influence of operational and design parameters on the effluent quality in terms of organic matter removal, with the exceptions of the BOD load upstream of the aeration tank and the sludge age in the unit. Results suggest that this system is well suited for the treatment of domestic sewage.

Study on Treatment of acidic and highly concentrated fluoride waste water using calcium oxide-calcium chloride

NASA Astrophysics Data System (ADS)

Ren, T.; Gao, X. R.; Zheng, T.; Wang, P.

2016-08-01

There are problems with treating acidic waste water containing high concentration fluorine by chemical precipitation, including the low sludge setting velocity and the high difficulty of reaching the criterion. In Heilongjiang province, a graphite factory producing high-purity graphite generates acidic waste water with a high concentration of fluorine. In this paper, the effect of removals on the concentration of fluoride with the combined treatment of calcium oxide and calcium chloride were discussed with regard to acid waste water. The study improved the sludge characteristics by using polyacrylamide (PAM) and polymeric aluminum chloride (PAC). The effect of different coagulants on sludge was evaluated by the sludge settlement ratio (SV), sludge volume index (SVI) and sludge moisture content. The results showed that the optimal combination for 100 ml waste water was calcium oxide addition amount of 14 g, a calcium chloride addition amount of 2.5 g, a PAM addition amount of 350 mg/L, and the effluent fluoride concentration was below 6 mg/L. PAM significantly improved the sludge settling velocity. The sludge settlement ratio reduced from 87.6% to 60%. The process for wastewater treatment was easily operated and involved low expenditure.

Enhancement of anaerobic digestion efficiency of wastewater sludge and olive waste: Synergistic effect of co-digestion and ultrasonic/microwave sludge pre-treatment.

PubMed

Alagöz, B Aylin; Yenigün, Orhan; Erdinçler, Ayşen

2015-12-01

This study investigates the effect of ultrasonic and microwave pre-treatment on biogas production from the anaerobic co-digestion of olive pomace and wastewater sludges. It was found that co-digestion of wastewater sludge with olive pomace yielded around 0.21 L CH4/g VS added, whereas the maximum methane yields from the mono-digestion of olive pomace and un-pretreated wastewater sludges were 0.18 and 0.16L CH4/g VS added. In the same way, compared to mono-digestion of these substrates, co-digestion increased methane production by 17-31%. The microwave and ultrasonic pre-treatments applied to sludge samples prior to co-digestion process led to further increase in the methane production by 52% and 24%, respectively, compared to co-digestion with un-pretreated wastewater sludge. The highest biogas and methane yields were obtained from the co-digestion of 30 min microwave pre-treated wastewater sludges and olive pomace to be 0.46 L/g VS added and 0.32 L CH4/g VS added, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Treatment and disposal of refinery sludges: Indian scenario.

PubMed

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.

K Basin sludge polychlorinated biphenyl removal technology assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashworth, S.C.

The two Hanford K Basins are water-filled concrete pools that contain over 2,100 metric tons of N Reactor fuel elements stored in aluminum or stainless steel canisters. During the time the fuel has been stored, approximately 50 m3 of heterogeneous solid material have accumulated in the basins. This material, referred to as sludge, is a mixture of fuel corrosion products, metallic bits of spent fuel and zirconium clad iron and metal corrosion products and silica from migrating sands. Some of the sludges also contain PCBs. The congener group of PCBs was identified as Aroclor 1254. The maximum concentration of sludgemore » PCBS was found to be 140 ppm (as settled wet basis). However, the distribution of the PCBs is non-uniform throughout the sludge (i.e., there are regions of high and low concentrations and places where no PCBs are present). Higher concentrations could be present at various locations. Aroclors 1016/1242, 1221, 1248, 1254, and 1260 were identified and quantified in K West (KW) Canister sludge. In some of these samples, the concentration of 1260 was higher than 1254. The sludge requires pre-treatment to meet tank farm waste acceptance criteria, Among the numerous requirements, the sludge should be retreated so that it does not contain regulated levels of Toxic Substances Control Act (TSCA) compounds. Because of their stable chemistry and relative insolubility in water, PCBs are difficult to treat. They also resist degradation from heat and electrical charges. This stability has resulted in environmental persistence which has prompted the development of a variety of new cleanup processes including supercritical processes, advanced oxidation, dehalogenation and others. Hopefully, most of the new processes are discussed herein. Information on new processes are being received and will be evaluated in a future revision.« less

Impact of sludge treatments on the extractability and fate of acetyl sulfamethoxazole residues in amended soils.

PubMed

Geng, Chunnu; Bergheaud, Valérie; Garnier, Patricia; Zhu, Yong-Guan; Haudin, Claire-Sophie

2018-03-01

Sludge recycled in agriculture may bring antibiotics into cropped soils. The nature, total amount, and availability of the antibiotics in soil partly depend on the sludge treatments. Our paper compares the fate of N-acetyl sulfamethoxazole (AC-SMX) residues between soils incubated with the same sludge but submitted to different processes before being added in soil. The fate of 14 C-AC-SMX residues was studied in mixtures of soil and sludges at different treatment levels: 1) activated and 2) centrifuged sludges, both enriched with 14 C-AC-SMX, and 3) limed and 4) heat-dried sludges obtained by treating the previously contaminated centrifuged sludge. The evolution of the extractability of 14 C residues (CaCl 2 , methanol) and their mineralization were followed during 119 days. More than 80% of the initial 14 C-activity was no longer extractable after 14 days, except in soil with limed sludge. Liming and drying the centrifuged sludge decreased the mineralized 14 C fraction from 5.7-6.4% to 1.2-1.8% and consequently, the corresponding soils contained more 14 C residues after 119 days. Although 14 C residues were more CaCl 2 -extractable in soil with limed sludge, they seemed to be poorly bioavailable for biodegradation. For all solid sludges, the mineralization rate of 14 C-AC-SMX residues was strongly correlated to that of sludge organic carbon, with a coefficient three times lower for the limed and dried sludges than for the centrifuged sludge after 14 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of operational parameters on nitrogen removal efficiency and microbial communities in a full-scale activated sludge process.

PubMed

Kim, Young Mo; Cho, Hyun Uk; Lee, Dae Sung; Park, Donghee; Park, Jong Moon

2011-11-01

To improve the efficiency of total nitrogen (TN) removal, solid retention time (SRT) and internal recycling ratio controls were selected as operating parameters in a full-scale activated sludge process treating high strength industrial wastewater. Increased biomass concentration via SRT control enhanced TN removal. Also, decreasing the internal recycling ratio restored the nitrification process, which had been inhibited by phenol shock loading. Therefore, physiological alteration of the bacterial populations by application of specific operational strategies may stabilize the activated sludge process. Additionally, two dominant ammonia oxidizing bacteria (AOB) populations, Nitrosomonas europaea and Nitrosomonas nitrosa, were observed in all samples with no change in the community composition of AOB. In a nitrification tank, it was observed that the Nitrobacter populations consistently exceeded those of the Nitrospira within the nitrite oxidizing bacteria (NOB) community. Through using quantitative real-time PCR (qPCR), nirS, the nitrite reducing functional gene, was observed to predominate in the activated sludge of an anoxic tank, whereas there was the least amount of the narG gene, the nitrate reducing functional gene. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

PubMed

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

2009-04-15

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

Influence of tetracycline on tetracycline-resistant heterotrophs and tet genes in activated sludge process.

PubMed

Yu, Jie; Liu, Dongfang; Li, Kexun

2015-03-01

The concentrations of tetracycline-intermediate resistant, tetracycline-resistant heterotrophic bacteria, and total heterotrophic bacteria were examined to assess the influence of tetracycline on tetracycline-resistant heterotrophs by the R2A agar cultivation method in the tetracycline fortified activated sludge process and in the natural background. Results showed that the percentages of both tetracycline-intermediate resistant and tetracycline-resistant heterotrophic bacteria in total heterotrophic bacteria were significantly increased, after tetracycline was fed to activated sludge for a 3 months period under four different operating conditions, as compared with the background. In order to investigate the mechanism of activated sludge resistance to tetracycline, polymerase chain reaction experiments were carried out to analyze the existence and evolution of tet genes in the presence of tetracycline. Results revealed that only tet A and tet B genes out of the 11 target tet genes were observed in tetracycline treated activated sludge while no tet gene was detected in background. This indicated that tet A gene could accumulate in activated sludge with slower and continuous influent, while the accumulation of tet B gene could be attributed to shorter hydraulic retention time. Therefore, it was proposed in this study that tetracycline-resistant genes created by efflux pumps spread earlier and quicker to encode resistance to tetracycline, which facilitated the increase in tetracycline-resistance.

Detection and Molecular Characterization of Hepatitis A Virus from Tunisian Wastewater Treatment Plants with Different Secondary Treatments

PubMed Central

Ouardani, Imen; Turki, Syrine; Aouni, Mahjoub

2016-01-01

ABSTRACT Hepatitis A virus (HAV) is the main causative agent of hepatitis infection associated with waterborne outbreaks worldwide. In Tunisia, there is no specific surveillance system for HAV and current secondary wastewater treatment processes are unable to remove viral particles, which present a potential public health problem. Qualitative and quantitative analysis of HAV in 271 raw and treated wastewater samples from five sewage treatment plants (STPs) during 13 months was performed. Moreover, the efficiency of three secondary wastewater treatment processes (conventional activated sludge, extended aeration, and oxidation ditch activated sludge) was evaluated. Data obtained demonstrated that HAV is endemic in Tunisia and circulates with high prevalence in both raw (66.9%) and treated (40.7%) wastewater. HAV circulates throughout the year in the coastal areas, with the highest rates found during summer and autumn, whereas in central Tunisia, high levels were shown in autumn and winter. Total virus removal was not achieved, since no difference in mean HAV loads was observed in effluents (6.0 × 103 genome copies [GC]/ml) and influents (2.7 × 103 GC/ml). The comparison of the HAV removal values of the three different wastewater treatment methods indicates that extended aeration and oxidation ditch activated sludge had better efficiency in removing viruses than conventional activated sludge did. Molecular characterization revealed that the vast majority of HAV strains belonged to subgenotype IA, with the cocirculation of subgenotype IB in wastewater treatment plants that collect tourism wastewater. IMPORTANCE This report provides important data on the incidence, behavior, seasonality, and genotype distribution of HAV in the environment in Tunisia, as well as the risk of infection derived from its occurrence in effluents due to inadequate wastewater treatment. In addition, these findings seem to confirm that the prevalence of HAV depends on socioeconomic level, sanitary conditions in the communities, sewage facilities, the locality, and the climate. The wide dispersion of HAV in effluents proves the inefficacity of the current wastewater treatment processes used in Tunisia to remove virus; therefore, establishment of tertiary treatment processes or replacement of the medium-charge activated sludge (conventional activated sludge) by the low-charge version (oxidation ditch activated sludge) is absolutely needed. Rapid detection of the HAV genome in wastewater may provide a timely warning sign to health authorities to implement population protection measures. PMID:27107113

EMERGING INFECTIOUS DISEASE AGENTS AND ISSUES ASSOCIATED WITH THE MANAGEMENT OF TREATED SLUDGES (BIOSOLIDS)

EPA Science Inventory

This presentation looks at the pathogenic microorganisms present in municipal sludges and the public's concerns with the land application of sludges/biosolids. Methods for reducing pathogens in sludge; methods for reducing the vector attractiveness of sludge; and issues associate...

Preparation and characteristics of bacterial polymer using pre-treated sludge from swine wastewater treatment plant.

PubMed

Guo, Junyuan; Yang, Chunping; Peng, Lanyan

2014-01-01

Sterilization, alkaline-thermal, and acid-thermal treatments were applied to different suspended sludge solids (SSS) concentrations and the pre-treated sludge was used as raw material for bioflocculant-producing bacteria R3 to produce bioflocculant. After 60 h of fermentation, three forms of bioflocculant (broth, capsular, and slime) were extracted, and maximum broth bioflocculant of 2.9 and 4.1 g L(-1) were produced in sterilized and alkaline-thermal treated sludge as compared to that of 1.8 g L(-1) in acid-thermal treated sludge. Higher bioflocculant quantity was produced in SS of 15, 25, and 35 g L(-1) compared to that produced in SS of 45, 55, and 65 g L(-1). Bioflocculant combined with 0.5 g Ca(2+) in 1.0 L kaolin suspension acted as conditioning agent, and maximum flocculating activity of 94.5% and 92.8% was achieved using broth and slime bioflocculant, respectively. The results demonstrated that wastewater sludge could be used as sources to prepare bioflocculants. Copyright © 2013 Elsevier Ltd. All rights reserved.

Vitrification as an alternative to landfilling of tannery sewage sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Celary, Piotr, E-mail: pcelary@is.pcz.czest.pl; Sobik-Szołtysek, Jolanta, E-mail: jszoltysek@is.pcz.czest.pl

Highlights: • The possibility of vitrification of tannery sewage sludge was investigated. • Glass cullet was substituted with different wastes of mineral character. • Component ratio in the processed mixtures was optimized. • Environmental safety of the acquired vitrificates was verified. • An alternative management approach of usually landfilled waste was presented. - Abstract: Due to high content of heavy metals such as chromium, tannery sewage sludge is a material which is difficult to be biologically treated as it is in the case of organic waste. Consequently, a common practice in managing tannery sewage sludge is landfilling. This poses amore » potential threat to both soil and water environments and it additionally generates costs of construction of landfills that meet specific environment protection requirements. Vitrification of this kind of sewage sludge with the addition of mineral wastes can represent an alternative to landfilling. The aim of this study was to investigate the possibility of obtaining an environmentally safe product by means of vitrification of tannery sewage sludge from a flotation wastewater treatment process and chemical precipitation in order to address the upcoming issue of dealing with sewage sludge from the tannery industry which will be prohibited to be landfilled in Poland after 2016. The focus was set on determining mixtures of tannery sewage sludge with additives which would result in the lowest possible heavy metal leaching levels and highest hardness rating of the products obtained from their vitrification. The plasma vitrification process was carried out for mixtures with various amounts of additives depending on the type of sewage sludge used. Only the materials of waste character were used as additives. One finding of the study was an optimum content of mineral additives in vitrified mixture of 30% v/v waste molding sands with 20% v/v carbonate flotation waste from the zinc and lead industry for the formulations with flotation sewage sludge, and 45% v/v and 5% v/v, respectively, for precipitation sewage sludge. These combinations allowed for obtaining products with negligible heavy metal leaching levels and hardness similar to commercial glass, which suggests they could be potentially used as construction aggregate substitutes. Incineration of sewage sludge before the vitrification process lead to increased hardness of the vitrificates and reduced leaching of some heavy metals.« less

High-strength N-methyl-2-pyrrolidone-containing process wastewater treatment using sequencing batch reactor and membrane bioreactor: A feasibility study.

PubMed

Loh, Chun Heng; Wu, Bing; Ge, Liya; Pan, Chaozhi; Wang, Rong

2018-03-01

N-methyl-2-pyrrolidone (NMP) is widely used as a solvent in polymeric membrane fabrication process, its elimination from the process wastewater (normally at a high concentration > 1000 mg/L) prior to discharge is essential because of environmental concern. This study investigated the feasibility of treating high-strength NMP-containing process wastewater in a sequencing batch reactor (SBR; i.e., batch feeding and intermittent aerobic/anoxic condition) and a membrane bioreactor (MBR; i.e., continuous feeding and aeration), respectively. The results showed that the SBR with the acclimated sludge was capable of removing >90% of dissolved organic carbon (DOC) and almost 98% of NMP within 2 h. In contrast, the MBR with the acclimated sludge showed a decreasing NMP removal efficiency from 100% to 40% over 15-day operation. The HPLC and LC-MS/MS analytical results showed that NMP degradation in SBR and MBR could undergo different pathways. This may be attributed to the dissimilar bacterial community compositions in the SBR and MBR as identified by 16s rRNA gene sequencing analysis. Interestingly, the NMP-degrading capability of the activated sludge derived from MBR could be recovered to >98% after they were operated at the SBR mode (batch feeding mode with intermittent aerobic/anoxic condition). This study reveals that SBR is probably a more feasible process to treat high-strength NMP-containing wastewater, but residual NMP metabolites in the SBR effluent need to be post-treated by an oxidation or adsorption process in order to achieve zero-discharge of toxic chemicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhancing aerobic digestion potential of municipal waste-activated sludge through removal of extracellular polymeric substance.

PubMed

Merrylin, J; Kaliappan, S; Kumar, S Adish; Yeom, Ick-Tae; Banu, J Rajesh

2014-01-01

A protease-secreting bacteria was used to pretreat municipal sewage sludge to enhance aerobic digestion. To enhance the accessibility of the sludge to the enzyme, extracellular polymeric substances were removed using citric acid thereby removing the flocs in the sludge. The conditions for the bacterial pretreatment were optimized using response surface methodology. The results of the bacterial pretreatment indicated that the suspended solids reduction was 18% in sludge treated with citric acid and 10% in sludge not treated with citric acid whereas in raw sludge, suspended solids reduction was 5.3%. Solubilization was 10.9% in the sludge with extracellular polymeric substances removed in contrast to that of the sludge with extracellular polymeric substances, which was 7.2%, and that of the raw sludge, which was just 4.8%. The suspended solids reduction in the aerobic reactor containing pretreated sludge was 52.4% whereas that in the control reactor was 15.3%. Thus, pretreatment with the protease-secreting bacteria after the removal of extracellular polymeric substances is a cost-effective and environmentally friendly method.

Municipal sewage sludge application on Ohio farms: tissue metal residues and infections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, C.S.; Dorn, C.R.; Lamphere, D.N.

1985-12-01

Transmission of infectious agents and translocation of Cd, Cu, Pb, and Zn from anaerobically digested sludge to the tissues of farm animals grazing on pastures to which sludge was applied (2-10 metric tons per hectare) were studied on eight farms. No significant health risk associated with the possible presence in sludge of Salmonella spp., or of common animal parasites including Nematodirus spp., Strongylus spp., Strongyloides spp., Trichuris spp., Eimeria spp., Ascaris spp., and Ancylostomum spp. was noted. Caudal fold as well as cervical tuberculin testing indicated no conversions from negative to positive following exposure of cattle to sludge. Significantly highermore » fecal Cd concentrations were detected in samples collected from cattle soon after being placed on sludge-treated pastures compared to preexposure values in the same animals. Significant Cd and Pb accumulations were found in the kidneys of calves grazing sludge-treated pastures compared to control calves. Although older cows grazing sludge-treated pastures had significantly higher blood Pb levels, no metal accumulation was observed in other tissues. Statistically significant accumulations of Cd and Pb in the kidney of calves grazing these pastures for a relatively short period suggest that caution should be exercised to avoid prolonged grazing of cattle on pastures receiving heavy sludge applications, especially with sludges containing high concentrations of heavy metals.« less

Proposal of a sequential treatment methodology for the safe reuse of oil sludge-contaminated soil.

PubMed

Mater, L; Sperb, R M; Madureira, L A S; Rosin, A P; Correa, A X R; Radetski, C M

2006-08-25

In this study sequential steps were used to treat and immobilize oil constituents of an oil sludge-contaminated soil. Initially, the contaminated soil was oxidized by a Fenton type reaction (13 wt% for H(2)O(2); 10mM for Fe(2+)). The oxidative treatment period of 80 h was carried out under three different pH conditions: 20 h at pH 6.5, 20 h at pH 4.5, and 40 h at pH 3.0. The oxidized contaminated sample (3 kg) was stabilized and solidified for 2h with clay (1 kg) and lime (2 kg). Finally, this mixture was solidified by sand (2 kg) and Portland cement (4 kg). In order to evaluate the efficiency of different processes to treat and immobilize oil contaminants of the oil sludge-contaminated soil, leachability and solubility tests were performed and extracts were analyzed according to the current Brazilian waste regulations. Results showed that the Fenton oxidative process was partially efficient in degrading the oil contaminants in the soil, since residual concentrations were found for the PAH and BTEX compounds. Leachability tests showed that clay-lime stabilization/solidification followed by Portland cement stabilization/solidification was efficient in immobilizing the recalcitrant and hazardous constituents of the contaminated soil. These two steps stabilization/solidification processes are necessary to enhance environmental protection (minimal leachability) and to render final product economically profitable. The treated waste is safe enough to be used on environmental applications, like roadbeds blocks.

Systematic comparison of mechanical and thermal sludge disintegration technologies.

PubMed

Wett, B; Phothilangka, P; Eladawy, A

2010-06-01

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis. Copyright 2009 Elsevier Ltd. All rights reserved.

Pharmaceuticals and personal care products in untreated and treated sewage sludge: Occurrence and environmental risk in the case of application on soil - A critical review.

PubMed

Verlicchi, P; Zambello, E

2015-12-15

This review is based on 59 papers published between 2002 and 2015, referring to about 450 treatment trains providing data regarding sludge concentrations for 169 compounds, specifically 152 pharmaceuticals and 17 personal care products, grouped into 28 different classes. The rationale of the study is to provide data to evaluate the environmental risk posed by the spreading of treated sludge in agriculture. Following discussion of the legislative scenario governing the final disposal of treated sludge in European countries and the USA, the study provides a snapshot of the occurrence of selected compounds in primary, secondary, mixed, digested, conditioned, composted and dried sludge originating in municipal wastewater treatment plants fed mainly with urban wastewater as well as in sludge-amended soil. Not only are measured values reported, but also predicted concentrations based on Kd values are reported. It emerges that in secondary sludge, the highest concentrations were found for fragrances, antiseptics and antibiotics and an attenuation in their concentrations occurs during treatment, in particular anaerobic digestion and composting. An in-depth literature survey of the (measured and predicted) Kd values for the different compounds and treated sludge are reported and an analysis of the influence of pH, redox conditions, sludge type was carried out. The data regarding measured and predicted concentrations of selected compounds in sludge-amended soil is then analyzed. Finally an environmental risk assessment posed by their occurrence in soil in the case of land application of sludge is examined, and the results obtained by different authors are compared. The most critical compounds found in the sludge-amended soil are estradiol, ciprofloxacin, ofloxacin, tetracycline, caffeine, triclosan and triclocarban. The study concludes with a focus on the main issues that should be further investigated in order to refine the environmental risk assessment. Copyright © 2015 Elsevier B.V. All rights reserved.

Characteristics of the microwave pyrolysis and microwave CO2-assisted gasification of dewatered sewage sludge.

PubMed

Chun, Young Nam; Jeong, Byeo Ri

2017-07-28

Microwave drying-pyrolysis or drying-gasification characteristics were examined to convert sewage sludge into energy and resources. The gasification was carried out with carbon dioxide as a gasifying agent. The examination results were compared with those of the conventional heating-type electric furnace to compare both product characteristics. Through the pyrolysis or gasification, gas, tar, and char were generated as products. The produced gas was the largest component of each process, followed by the sludge char and the tar. During the pyrolysis process, the main components of the produced gas were hydrogen and carbon monoxide, with a small amount of hydrocarbons such as methane and ethylene. In the gasification process, however, the amount of carbon monoxide was greater than the amount of hydrogen. In microwave gasification, a large amount of heavy tar was produced. The largest amount of benzene in light tar was generated from the pyrolysis or gasification. Ammonia and hydrogen cyanide, which are precursors of NO x , were also generated. In the microwave heating method, the sludge char produced by pyrolysis and gasification had pores in the mesopore range. This could be explained that the gas obtained from the microwave pyrolysis or gasification of the wet sewage sludge can be used as an alternative fuel, but the tar and NO x precursors in the produced gas should be treated. Sludge char can be used as a biomass solid fuel or as a tar removal adsorbent if necessary.

Fenton process combined with coagulation for the treatment of black liquor from bioethanol wastewater

NASA Astrophysics Data System (ADS)

Muryanto, Muryanto; Hanifah, Ummu; Amriani, Feni; Ibadurrahman, Ahmad Faiz; Sari, Ajeng Arum

2017-11-01

High amounts of black liquor are generated from bioethanol production by using oil palm empty fruit bunches. The black liquor is waste from alkaline pretreatment, it contains high amount of an alkaline solution (NaOH). The black liquor wastewater was highly contaminated with organic materials, and quite toxic for aquatic ecosystems if discharged directly into waters. This study aimed to determine ability of Fenton process combined with coagulation to treat black liquor. The addition 5% of polyaluminium chloride (PAC) could decolorized black liquor, degraded lignin, and produced sludge 70.64%, 68.28%, and 2.76 gram, respectively. Decolorization of black liquor was in line with degradation of black liquor because lignin is the main compound in black liquor. SEM images after addition of PAC of 5% indicated fragmentation of structure. Fenton reagent consist of 0.7 M FeSO4+ 3M H2O2 has able to decolorize black liquor, degrade lignin, and produce sludge 51.67% and 25.44%, and 0.44 gram, respectively. It was concluded that black liquor wastewater from bioethanol can be treated by using Fenton process combined with coagulation. However, these methods still need improvement to obtain the higher degradation rate, and coagulation sludge needs further consideration.

Fate of personal care and household products in source separated sanitation.

PubMed

Butkovskyi, A; Rijnaarts, H H M; Zeeman, G; Hernandez Leal, L

2016-12-15

Removal of twelve micropollutants, namely biocides, fragrances, ultraviolet (UV)-filters and preservatives in source separated grey and black water treatment systems was studied. All compounds were present in influent grey water in μg/l range. Seven compounds were found in influent black water. Their removal in an aerobic activated sludge system treating grey water ranged from 59% for avobenzone to >99% for hexylcinnamaldehyde. High concentrations of hydrophobic micropollutants in sludge of aerobic activated sludge system indicated the importance of sorption for their removal. Six micropollutants were found in sludge of an Up-flow anaerobic sludge blanket (UASB) reactor treating black water, with four of them being present at significantly higher concentrations after addition of grey water sludge to the reactor. Hence, addition of grey water sludge to the UASB reactor is likely to increase micropollutant content in UASB sludge. This approach should not be followed when excess UASB sludge is designed to be reused as soil amendment. Copyright © 2016 Elsevier B.V. All rights reserved.

Three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy with regional integration analysis for assessing waste sludge hydrolysis treated with multi-enzyme and thermophilic bacteria.

PubMed

Guo, Liang; Lu, Mingmin; Li, Qianqian; Zhang, Jiawen; Zong, Yan; She, Zonglian

2014-11-01

The hydrolysis effect of waste sludge after multi-enzyme and thermophilic bacteria pretreatments is investigated using excitation-emission matrix (EEM) with fluorescence regional integration (FRI) in this study. The compositional characteristics of extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed to evaluate the sludge disintegration. The EPS and cell wall in sludge were disrupted after hydrolysis which led to carbohydrate, protein and soluble chemical oxygen demand (SCOD) of DOM increasing in sludge supernatant. The bio-degradability level in the extracted fractions of EPS and DOM depending on the fluorescence zones was found after hydrolysis. The highest proportion of percent fluorescence response (Pi,n) in EPS and DOM was soluble microbial by-product and humic acid-like organics. A significant increase of humic acid-like organics in DOM after thermophilic bacteria hydrolysis was obtained. The assessment of hydrolysis using EEM coupled with FRI provided a new insight toward the bio-utilization process of waste sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of activated sludge acclimation aeration time on bayberry wastewater

NASA Astrophysics Data System (ADS)

Shi, Liang; He, Lingfeng; Zhang, Yongli

2018-03-01

Taking the myrica rubra pickle wastewater of Chaozhou Kang Hui group as the water sample, biochemical method was used to treat the wastewater, after domestication, the biochemical treatment was carried out. The influence of time on COD index was investigated. The results showed that: tap water: sewage: sludge = 1:1:1, 900 mL each. Under the action of 30 min time, the supernatant was taken at 100 mL, and the wastewater was added to 900 mL,. Under the action of activated sludge, the degradation of myrica rubra wastewater samples, after domestication 84 h, the effect is better. Under this condition, the standard of SBR process for wastewater treatment is reached.

Simultaneous Cr(VI) bio-reduction and methane production by anaerobic granular sludge.

PubMed

Hu, Qian; Sun, Jiaji; Sun, Dezhi; Tian, Lan; Ji, Yanan; Qiu, Bin

2018-08-01

Wastewater containing toxic hexavalent chromium (Cr(VI)) were treated with well-organized anaerobic granular sludge in this study. Results showed that the anaerobic granular sludge rapidly removed Cr(VI), and 2000 µg·L -1 Cr(VI) was completely eliminated within 6 min, which was much faster than the reported duration of removal by reported artificial materials. Sucrose added as a carbon source acted as an initial electron donor to reduce Cr(VI) to Cr(III). This process was considered as the main mechanism of Cr(VI) removal. Methane production by anaerobic granular sludge was improved by the addition of Cr(VI) at a concentration lower than 500 µg·L -1 . Anaerobic granular sludge had a well-organized structure, which presented good resistance against toxic Cr(VI). Trichoccus accelerated the degradation of organic substances to generate acetates with a low Cr(VI) concentration, thereby enhancing methane production by acetotrophic methanogens. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anaerobic digestion of thermal pre-treated emulsified slaughterhouse wastes (TESW): Effect of trace element limitation on process efficiency and sludge metabolic properties.

PubMed

Eftaxias, Alexandros; Diamantis, Vasileios; Aivasidis, Alexandros

2018-06-01

Slaughterhouse solid wastes, characterized by a high lipid content, are considered a valuable resource for energy production by means of anaerobic digestion technologies. Aim of this study was to examine the effect of trace element limitation on the mesophilic anaerobic digestion of thermally pre-treated emulsified slaughterhouse wastes (TESW). Under two distinct experimental periods (Period I - low and Period II - high trace element dosage respectively) a CSTR with sludge recirculation was operated at increasing organic loading rate (OLR) from 1.5 to 10 g L -1  d -1 . Under optimum conditions, COD removal was higher than 96%, biogas yield equal to 0.53 L g -1  COD feed and the biogas methane content 77%. Trace element limitation however, resulted in a dramatic decline in process efficiency, with VFA accumulation and events of extreme sludge flotation, despite that the soluble concentration of Ni, Co and Mo were between 12 and 28 μg L -1 . This is indicative of mass transfer limitations caused by lipids adsorption onto the anaerobic biomass. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biodegradation of phytosanitary products in biological wastewater treatment.

PubMed

Massot, A; Estève, K; Noilet, P; Méoule, C; Poupot, C; Mietton-Peuchot, M

2012-04-15

Agricultural activity generates two types of waste: firstly, biodegradable organic effluents generally treated by biological processes and, secondly, phytosanitary effluents which contain residues of plant protection products. The latter are collected and treated. Current technological solutions are essentially based on concentration or physical-chemical processes. However, recent improvements in the biodegradability of pesticides open the way to the consideration of alternative, biological, treatment using mixed liquor from wastewater plant activated sludge. The feasibility of the biological treatment of viticultural effluents has been evaluated by the application of pesticides to activated sludge. The necessity for selection of a pesticide-resistant biomass has been highlighted. The elimination of the phytosanitary products shows the potential of a resistant biomass in the treatment of pesticides. The aerated biological storage ponds at three wineries, followed by a sand or reed-bed filter, were used for the treatment of the total annual volume of the viticulture effluents and validate the laboratory experiments. The results show that the biological purification of pesticides by activated sludge is possible by allowing approximately 8 days for biomass adaptation. Stability of purification occurs between 20 and 30 days. Copyright © 2012 Elsevier Ltd. All rights reserved.

ADM1-based methodology for the characterisation of the influent sludge in anaerobic reactors.

PubMed

Huete, E; de Gracia, M; Ayesa, E; Garcia-Heras, J L

2006-01-01

This paper presents a systematic methodology to characterise the influent sludge in terms of the ADM1 components from the experimental measurements traditionally used in wastewater engineering. For this purpose, a complete characterisation of the model components in their elemental mass fractions and charge has been used, making a rigorous mass balance for all the process transformations and enabling the future connection with other unit-process models. It also makes possible the application of mathematical algorithms for the optimal characterisation of several components poorly defined in the ADM1 report. Additionally, decay and disintegration have been necessarily uncoupled so that the decay proceeds directly to hydrolysis instead of producing intermediate composites. The proposed methodology has been applied to the particular experimental work of a pilot-scale CSTR treating real sewage sludge, a mixture of primary and secondary sludge. The results obtained have shown a good characterisation of the influent reflected in good model predictions. However, its limitations for an appropriate prediction of alkalinity and carbon percentages in biogas suggest the convenience of including the elemental characterisation of the process in terms of carbon in the analytical program.

Influence of mechanical disintegration on the microbial growth of aerobic sludge biomass: A comparative study of ultrasonic and shear gap homogenizers by oxygen uptake measurements.

PubMed

Divyalakshmi, P; Murugan, D; Sivarajan, M; Saravanan, P; Lajapathi Rai, C

2015-11-01

Wastewater treatment plant incorporates physical, chemical and biological processes to treat and remove the contaminants. The main drawback of conventional activated sludge process is the huge production of excess sludge, which is an unavoidable byproduct. The treatment and disposal of excess sludge costs about 60% of the total operating cost. The ideal way to reduce excess sludge production during wastewater treatment is by preventing biomass formation within the aerobic treatment train rather than post treatment of the generated sludge. In the present investigation two different mechanical devices namely, Ultrasonic and Shear Gap homogenizers have been employed to disintegrate the aerobic biomass. This study is intended to restrict the multiplication of microbial biomass and at the same time degrade the organics present in wastewater by increasing the oxidative capacity of microorganisms. The disintegrability on biomass was determined by biochemical methods. Degree of inactivation provides the information on inability of microorganisms to consume oxygen upon disruption. The soluble COD quantifies the extent of release of intra cellular compounds. The participation of disintegrated microorganism in wastewater treatment process was carried out in two identical respirometeric reactors. The results show that Ultrasonic homogenizer is very effective in the disruption of microorganisms leading to a maximum microbial growth reduction of 27%. On the other hand, Shear gap homogenizer does not favor the sludge growth reduction rather it facilitates the growth. This study also shows that for better microbial growth reduction, floc size reduction alone is not sufficient but also microbial disruption is essential. Copyright © 2015 Elsevier Inc. All rights reserved.

Predicting the drying properties of sludge based on hydrothermal treatment under subcritical conditions.

PubMed

Mäkelä, Mikko; Fraikin, Laurent; Léonard, Angélique; Benavente, Verónica; Fullana, Andrés

2016-03-15

The effects of hydrothermal treatment on the drying properties of sludge were determined. Sludge was hydrothermally treated at 180-260 °C for 0.5-5 h using NaOH and HCl as additives to influence reaction conditions. Untreated sludge and attained hydrochar samples were then dried under identical conditions with a laboratory microdryer and an X-ray microtomograph was used to follow changes in sample dimensions. The effective moisture diffusivities of sludge and hydrochar samples were determined and the effect of process conditions on respective mean diffusivities evaluated using multiple linear regression. Based on the results the drying time of untreated sludge decreased from approximately 80 min to 37-59 min for sludge hydrochar. Drying of untreated sludge was governed by the falling rate period where drying flux decreased continuously as a function of sludge moisture content due to heat and mass transfer limitations and sample shrinkage. Hydrothermal treatment increased the drying flux of sludge hydrochar and decreased the effect of internal heat and mass transfer limitations and sample shrinkage especially at higher treatment temperatures. The determined effective moisture diffusivities of sludge and hydrochar increased as a function of decreasing moisture content and the mean diffusivity of untreated sludge (8.56·10(-9) m(2) s(-1)) and sludge hydrochar (12.7-27.5·10(-9) m(2) s(-1)) were found statistically different. The attained regression model indicated that treatment temperature governed the mean diffusivity of hydrochar, as the effects of NaOH and HCl were statistically insignificant. The attained results enabled prediction of sludge drying properties through mean moisture diffusivity based on hydrothermal treatment conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioprocessing for elimination antibiotics and hormones from swine wastewater.

PubMed

Cheng, D L; Ngo, H H; Guo, W S; Liu, Y W; Zhou, J L; Chang, S W; Nguyen, D D; Bui, X T; Zhang, X B

2018-04-15

Antibiotics and hormones in swine wastewater have become a critical concern worldwide due to the severe threats to human health and the eco-environment. Removal of most detectable antibiotics and hormones, such as sulfonamides (SAs), SMs, tetracyclines (TCs), macrolides, and estrogenic hormones from swine wastewater utilizing various biological processes were summarized and compared. In biological processes, biosorption and biodegradation are the two major removal mechanisms for antibiotics and hormones. The residuals in treated effluents and sludge of conventional activated sludge and anaerobic digestion processes can still pose risks to the surrounding environment, and the anaerobic processes' removal efficiencies were inferior to those of aerobic processes. In contrast, membrane bioreactors (MBRs), constructed wetlands (CWs) and modified processes performed better because of their higher biodegradation of toxicants. Process modification on activated sludge, anaerobic digestion and conventional MBRs could also enhance the performance (e.g. removing up to 98% SMs, 88.9% TCs, and 99.6% hormones from wastewater). The hybrid process combining MBRs with biological or physical technology also led to better removal efficiency. As such, modified conventional biological processes, advanced biological technologies and MBR hybrid systems are considered as a promising technology for removing toxicants from swine wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

Previously unclassified bacteria dominate during thermophilic and mesophilic anaerobic pre-treatment of primary sludge.

PubMed

Pervin, Hasina M; Batstone, Damien J; Bond, Philip L

2013-06-01

Thermophilic biological pre-treatment enables enhanced anaerobic digestion for treatment of wastewater sludges but, at present, there is limited understanding of the hydrolytic-acidogenic microbial composition and its contribution to this process. In this study, the process was assessed by comparing the microbiology of thermophilic (50-65 °C) and mesophilic (35 °C) pre-treatment reactors treating primary sludge. A full-cycle approach for the 16S rRNA genes was applied in order to monitor the diversity of bacteria and their abundance in a thermophilic pre-treatment reactor treating primary sludge. For the thermophilic pre-treatment (TP), over 90% of the sequences were previously undetected and these had less than 97% sequence similarity to cultured organisms. During the first 83 days, members of the Betaproteobacteria dominated the community sequences and a newly designed probe was used to monitor a previously unknown bacterium affiliated with the genus Brachymonas. Between days 85 and 183, three phylotypes that affiliated with the genera Comamonas, Clostridium and Lysobacter were persistently dominant in the TP community, as revealed by terminal-restriction fragment length polymorphism (T-RFLP). Hydrolytic and fermentative functions have been speculated for these bacteria. Mesophilic pre-treatment (MP) and TP communities were different but they were both relatively dynamic. Statistical correlation analysis and the function of closely allied reference organisms indicated that previously unclassified bacteria dominated the TP community and may have been functionally involved in the enhanced hydrolytic performance of thermophilic anaerobic pre-treatment. This study is the first to reveal the diversity and dynamics of bacteria during anaerobic digestion of primary sludge. Copyright © 2013 Elsevier GmbH. All rights reserved.

Effect of feed characteristics on the organic matter, nitrogen and phosphorus removal in an activated sludge system treating piggery slurry.

PubMed

González, C; García, P A; Muñoz, R

2009-01-01

Piggery wastewater is characterized by its high content in nitrogen and phosphorus, as well as by a low C/N ratio. This type of wastewater is traditionally spread to croplands (with its subsequent leaching to groundwater) or rarely discharged into natural water bodies, which ultimately cause severe episodes of eutrophication in aquatic ecosystems. In this context, activated sludge systems constitute a robust and efficient treatment option. The performance of an activated sludge process using a pre-denitrification configuration treating both sieved and flocculated swine slurry at a hydraulic retention time (HRT) of 7.7 days was evaluated. In order to avoid bacterial wash-out, sludge from the settler was recirculated to the anoxic tank to accomplish denitrification. Once the biomass was acclimatized, the reactor was fed with swine slurry containing 19, 2.6, and 0.27 g/L of total chemical oxygen demand (COD), total Kjeldhal nitrogen (TKN), and soluble P, respectively. Nitrogen removal showed a clear dependency on the influent composition. When the influent TKN/total COD and soluble COD/total COD ratios were respectively 0.12-0.15 and 0.7, the reactor exhibited good removal efficiencies (up to 99 and 91 for N-NH(4)(+), TKN, respectively) while PO(4)(3-) was removed up to 65%. However, when the influent TKN/total COD ratio rose to 0.26 and soluble COD/total COD decreased to 0.3, the denitrification process was severely hindered concomitant with and accumulation of nitrite. Nevertheless, organic matter degradation was not affected by influent composition. At the last stage of the experiment, removals of dissolved phosphorus fell to 40% when the redox potential (ORP) profile showed a constant value of -400 mV, likely due to phosphate released from bacterial sludge.

Potential of phosphorus recovery from sewage sludge and manure ash by thermochemical treatment.

PubMed

Havukainen, Jouni; Nguyen, Mai Thanh; Hermann, Ludwig; Horttanainen, Mika; Mikkilä, Mirja; Deviatkin, Ivan; Linnanen, Lassi

2016-03-01

All life forms require phosphorus (P), which has no substitute in food production. The risk of phosphorus loss from soil and limited P rock reserves has led to the development of recycling P from industrial residues. This study investigates the potential of phosphorus recovery from sewage sludge and manure ash by thermochemical treatment (ASH DEC) in Finland. An ASH DEC plant could receive 46-76 kt/a of sewage sludge ash to produce 51-85 kt/a of a P-rich product with a P2O5 content of 13-18%, while 320-750 kt/a of manure ash could be supplied to produce 350-830 kt/a of a P-rich product with a P content of 4-5%. The P2O5 potential in the total P-rich product from the ASH DEC process using sewage sludge and manure ash is estimated to be 25-47 kt/a, which is significantly more than the P fertilizer demand in Finland's agricultural industries. The energy efficiency of integrated incineration and the ASH DEC process is more dependent on the total solid content and the subsequent need for mechanical dewatering and thermal drying than on the energy required by the ASH DEC process. According to the results of this study, the treated sewage sludge and manure ash using the ASH DEC process represent significant potential phosphorus sources for P fertilizer production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distribution, partition and removal of polycyclic aromatic hydrocarbons (PAHs) during coking wastewater treatment processes.

PubMed

Zhang, Wanhui; Wei, Chaohai; An, Guanfeng

2015-05-01

In this study, we report the performance of a full-scale conventional activated sludge (A-O1-O2) treatment in eliminating polycyclic aromatic hydrocarbons (PAHs). Both aqueous and solid phases along with the coking wastewater treatment processes were analyzed for the presence of 18 PAHs. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent and sludge samples. In the coking wastewater treatment system, 4-5 ring PAHs were the dominant compounds, while 4 rings PAHs predominated in the sludge samples. Over 98% of the PAH removal was achieved in the coking wastewater treatment plant (WWTP), with the total concentration of PAHs being 21.3 ± 1.9 μg L(-1) in the final effluent. During the coking wastewater treatment processes, the association of the lower molecular weight PAH with suspended solids was generally less than 60%, while the association of higher molecular weight PAHs was greater than 90%. High distribution efficiencies (Kdp and Kds) were found, suggesting that adsorption was the potential removal pathway of PAHs. Finally, the mass balances of PAHs in various stages of the coking WWTP were obtained, and the results indicated that adsorption to sludge was the main removal pathway for PAHs in the coking wastewater treatment processes.

Laboratory measurements of radiance and reflectance spectra of dilute primary-treated sewage sludge

NASA Technical Reports Server (NTRS)

Usry, J. W.; Witte, W. G.; Whitlock, C. H.; Gurganus, E. A.

1977-01-01

The feasibility of remotely monitoring ocean dumping of waste products such as acid and sewage sludge is evaluated. The laboratory arrangement, solar simulator, and test results from three experiments conducted in the laboratory are described. Radiance and reflectance spectra are presented for primary-treated sewage sludge mixed with two types of base water. Results indicate that upwelled reflectance varies in a near-linear manner with concentration and that the sludge has a practically flat signal response between 420 and 970 nm. Well-defined upwelled reflectance spectra were obtained for the sewage-sludge mixtures at all wavelengths and concentrations. The spectral-reflectance values appeared to be influenced by the type of base water, but this influence was small, especially for the mixtures with low concentrations of sewage sludge.

The effect of activated carbon addition on membrane bioreactor processes for wastewater treatment and reclamation - A critical review.

PubMed

Skouteris, George; Saroj, Devendra; Melidis, Paraschos; Hai, Faisal I; Ouki, Sabèha

2015-06-01

This review concentrates on the effect of activated carbon (AC) addition to membrane bioreactors (MBRs) treating wastewaters. Use of AC-assisted MBRs combines adsorption, biodegradation and membrane filtration. This can lead to advanced removal of recalcitrant pollutants and mitigation of membrane fouling. The relative contribution of adsorption and biodegradation to overall removal achieved by an AC-assisted MBR process can vary, and "biological AC" may not fully develop due to competition of target pollutants with bulk organics in wastewater. Thus periodic replenishment of spent AC is necessary. Sludge retention time (SRT) governs the frequency of spent AC withdrawal and addition of fresh AC, and is an important parameter that significantly influences the performance of AC-assisted MBRs. Of utmost importance is AC dosage because AC overdose may aggravate membrane fouling, increase sludge viscosity, impair mass transfer and reduce sludge dewaterability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Illumina MiSeq sequencing reveals the key microorganisms involved in partial nitritation followed by simultaneous sludge fermentation, denitrification and anammox process.

PubMed

Wang, Bo; Peng, Yongzhen; Guo, Yuanyuan; Zhao, Mengyue; Wang, Shuying

2016-05-01

A combined process including a partial nitritation SBR (PN-SBR) followed by a simultaneous sludge fermentation, denitrification and anammox reactor (SFDA) was established to treat low C/N domestic wastewater in this study. An average nitrite accumulation rate of 97.8% and total nitrogen of 9.4mg/L in the effluent was achieved during 140days' operation. The underlying mechanisms were investigated by using Illumina MiSeq sequencing to analyze the microbial community structures in the PN-SBR and SFDA. Results showed that the predominant bacterial phylum was Proteobacteria in the external waste activated sludge (WAS, added to the SFDA) and SFDA while Bacteroidetes in the PN-SBR. Further study indicated that in the PN-SBR, the dominant nitrobacteria, Nitrosomonas genus, facilitated nitritation and little nitrate was generated in the PN-SBR effluent. In the SFDA, the co-existence of functional microorganisms Thauera, Candidatus Anammoximicrobium and Pseudomonas were found to contribute to simultaneous sludge fermentation, denitrification and anammox. Copyright © 2016 Elsevier Ltd. All rights reserved.

Process and system for treating waste water

DOEpatents

Olesen, Douglas E.; Shuckrow, Alan J.

1978-01-01

A process of treating raw or primary waste water using a powdered, activated carbon/aerated biological treatment system is disclosed. Effluent turbidities less than 2 JTU (Jackson turbidity units), zero TOC (total organic carbon) and in the range of 10 mg/l COD (chemical oxygen demand) can be obtained. An influent stream of raw or primary waste water is contacted with an acidified, powdered, activated carbon/alum mixture. Lime is then added to the slurry to raise the pH to about 7.0. A polyelectrolyte flocculant is added to the slurry followed by a flocculation period -- then sedimentation and filtration. The separated solids (sludge) are aerated in a stabilization sludge basin and a portion thereof recycled to an aerated contact basin for mixing with the influent waste water stream prior to or after contact of the influent stream with the powdered, activated carbon/alum mixture.

An alternative approach to recovering valuable metals from zinc phosphating sludge.

PubMed

Kuo, Yi-Ming

2012-01-30

This study used a vitrification process (with good potential for commercialization) to recover valuable metals from Zn phosphating sludge. The involved vitrification process achieves two major goals: it transformed hazardous Zn phosphating sludge into inert slag and it concentrated Fe (83.5%) and Zn (92.8%) into ingot and fine particulate-phase material, respectively. The Fe content in the ingot was 278,000 mg/kg, making the ingot a potential raw material for iron making. The fine particulate-phase material (collected from flue gas) contained abundant Zn (544,000 mg/kg) in the form of ZnO. The content (67.7%) of ZnO was high, so it can be directly sold to refineries. The recovered coarse particulate-phase material, with insufficient amount of ZnO, can be recycled as a feeding material for Zn re-concentration. Therefore, the vitrification process can not only treat hazardous materials but also effectively recover valuable metals. Copyright © 2011 Elsevier B.V. All rights reserved.

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

PubMed

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

2017-03-01

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

Microwave oxidation treatment of sewage sludge.

PubMed

Lo, Kwang V; Srinivasan, Asha; Liao, Ping H; Bailey, Sam

2015-01-01

Microwave-oxidation treatment of sewage sludge using various oxidants was studied. Two treatment schemes with a combination of hydrogen peroxide and ozone were examined: hydrogen peroxide and ozone were introduced into the sludge simultaneously, followed by microwave heating. The other involved the ozonation first, and then the resulting solution was subjected to microwave and hydrogen peroxide treatment. The set with ozonation followed by hydrogen peroxide plus microwave heating yielded higher soluble materials than those of the set with hydrogen peroxide plus ozone first and then microwave treatment. No settling was observed for all treatments in the batch operation, except ozone/microwave plus hydrogen peroxide set at 120°C. The pilot-scale continuous-flow 915 MHz microwave study has demonstrated that microwave-oxidation process is feasible for real-time industrial application. It would help in providing key data for the design of a full-scale system for treating sewage sludge and the formulation of operational protocols.

Fractionation of heavy metals in liquefied chromated copper arsenate (CCA)-treated wood sludge using a modified BCR-sequential extraction procedure

Treesearch

Hui Pan; Chung-Yun Hse; Robert Gambrell; Todd F. Shupe

2009-01-01

Chromated copper arsenate (CCA)-treated wood was liquefied with polyethylene glycol/glycerin and sulfuric acid. After liquefaction, most CCA metals (98% As, 92% Cr, and 83% Cu) were removed from liquefied CCA-treated wood by precipitation with calcium hydroxide. The original CCA-treated wood and liquefied CCA-treated wood sludge were fractionated by a modified...

Detection and Molecular Characterization of Hepatitis A Virus from Tunisian Wastewater Treatment Plants with Different Secondary Treatments.

PubMed

Ouardani, Imen; Turki, Syrine; Aouni, Mahjoub; Romalde, Jesús L

2016-07-01

Hepatitis A virus (HAV) is the main causative agent of hepatitis infection associated with waterborne outbreaks worldwide. In Tunisia, there is no specific surveillance system for HAV and current secondary wastewater treatment processes are unable to remove viral particles, which present a potential public health problem. Qualitative and quantitative analysis of HAV in 271 raw and treated wastewater samples from five sewage treatment plants (STPs) during 13 months was performed. Moreover, the efficiency of three secondary wastewater treatment processes (conventional activated sludge, extended aeration, and oxidation ditch activated sludge) was evaluated. Data obtained demonstrated that HAV is endemic in Tunisia and circulates with high prevalence in both raw (66.9%) and treated (40.7%) wastewater. HAV circulates throughout the year in the coastal areas, with the highest rates found during summer and autumn, whereas in central Tunisia, high levels were shown in autumn and winter. Total virus removal was not achieved, since no difference in mean HAV loads was observed in effluents (6.0 × 10(3) genome copies [GC]/ml) and influents (2.7 × 10(3) GC/ml). The comparison of the HAV removal values of the three different wastewater treatment methods indicates that extended aeration and oxidation ditch activated sludge had better efficiency in removing viruses than conventional activated sludge did. Molecular characterization revealed that the vast majority of HAV strains belonged to subgenotype IA, with the cocirculation of subgenotype IB in wastewater treatment plants that collect tourism wastewater. This report provides important data on the incidence, behavior, seasonality, and genotype distribution of HAV in the environment in Tunisia, as well as the risk of infection derived from its occurrence in effluents due to inadequate wastewater treatment. In addition, these findings seem to confirm that the prevalence of HAV depends on socioeconomic level, sanitary conditions in the communities, sewage facilities, the locality, and the climate. The wide dispersion of HAV in effluents proves the inefficacity of the current wastewater treatment processes used in Tunisia to remove virus; therefore, establishment of tertiary treatment processes or replacement of the medium-charge activated sludge (conventional activated sludge) by the low-charge version (oxidation ditch activated sludge) is absolutely needed. Rapid detection of the HAV genome in wastewater may provide a timely warning sign to health authorities to implement population protection measures. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Mesophilic and thermophilic activated sludge post-treatment of paper mill process water.

PubMed

Vogelaar, J C T; Bouwhuis, E; Klapwijk, A; Spanjers, H; van Lier, J B

2002-04-01

Increasing system closure in paper mills and higher process water temperatures make the applicability of thermophilic treatment systems increasingly important. The use of activated sludge as a suitable thermophilic post-treatment system for anaerobically pre-treated paper process water from a paper mill using recycled wastepaper was studied. Two lab-scale plug flow activated sludge reactors were run in parallel for 6 months; a thermophilic reactor at 55 degrees C and a reference reactor at 30 degrees C. Both reactors were operated simultaneously at 20, 15 and 10 days SRT. The effects of temperature and SRT on sludge settleability and chemical oxygen demand (COD) removal efficiencies of different fractions were studied. Total COD removal percentages over the whole experimental period were 58+/-5% at 30 degrees C and 48 +/- 10% at 55 degrees C. The effect of the SRT on the total COD removal was negligible. Differences in total COD removal between both systems were due to a lesser removal of soluble and colloidal COD at 55 degrees C compared to the reference system. At 30 degrees C, colloidal COD removal percentages were 65+/-25%, 75+/-17% and 86+/-22% at 20, 15 and 10 days SRT, respectively. At 55 degrees C, these percentages were 48+/-34%, 40+/-28% and 70+/-25%, respectively. The effluent concentrations of colloidal COD in both systems were related to the influent concentration of colloidal material. The thermophilic sludge was not able to retain influent colloidal material as well as the mesophilic sludge causing a higher thermophilic effluent turbidity. Sludge settling properties were excellent in both reactor systems. These were neither temperature nor SRT dependent but were rather caused by extensive calcium precipitation in the aeration tanks creating a very dense sludge. For application in the board industry, a thermophilic in line treatment system seems feasible. The higher effluent turbidity is most likely offset by the energy gains of treatment under thermophilic conditions.

Use of PCR-DGGE Based Molecular Methods to Analyse Microbial Community Diversity and Stability during the Thermophilic Stages of an ATAD Wastewater Sludge Treatment Process as an Aid to Performance Monitoring

PubMed Central

Piterina, Anna V.; Pembroke, J. Tony

2013-01-01

PCR and PCR-DGGE techniques have been evaluated to monitor biodiversity indexes within an ATAD (autothermal thermophilic aerobic digestion) system treating domestic sludge for land spread, by examining microbial dynamics in response to elevated temperatures during treatment. The ATAD process utilises a thermophilic population to generate heat and operates at elevated pH due to degradation of sludge solids, thus allowing pasteurisation and stabilisation of the sludge. Genera-specific PCR revealed that Archaea, Eukarya and Fungi decline when the temperature reaches 59°C, while the bacterial lineage constitutes the dominant group at this stage. The bacterial community at the thermophilic stage, its similarity index to the feed material, and the species richness present were evaluated by PCR-DGGE. Parameters such as choice of molecular target (16S rDNA or rpoB genes), and electrophoresis condition, were optimised to maximise the resolution of the method for ATAD. Dynamic analysis of microbial communities was best observed utilising PCR-DGGE analysis of the V6-V8 region of 16S rDNA, while rpoB gene profiles were less informative. Unique thermophilic communities were shown to quickly adapt to process changes, and shown to be quite stable during the process. Such techniques may be used as a monitoring technique for process health and efficiency. PMID:25937969

Changes in the process performance, sludge production and microbial activity in an activated sludge reactor with addition of a metabolic uncoupler under different operating conditions.

PubMed

Ferrer-Polonio, E; Fernández-Navarro, J; Alonso-Molina, J L; Amorós-Muñoz, I; Bes-Piá, A; Mendoza-Roca, J A

2017-12-01

Sludge production in wastewater treatment plants is nowadays a big concern due to the high produced amounts and their characteristics. Consequently, the study of techniques that reduce the sludge generation in wastewater treatment plants is becoming of great importance. In this work, four laboratory sequencing batch reactors (SBRs), which treated municipal wastewater, were operated to study the effect of adding the metabolic uncoupler 3,3',4',5-tetrachlorosalicylanilide (TCS) on the sludge reduction, the SBRs performance and the microbial hydrolytic enzymatic activities (MHEA). In addition, different operating conditions of the SBRs were tested to study the effect of the TCS on the process: two dissolved oxygen (DO) concentrations (2 and 9 mg L -1 ) and two F/M ratio (0.18 and 0.35 g COD·g MLVSS -1 ·d -1 ). The sludge production decreased under high DO concentrations. At the same time, the DNA and EPS production increased in the four SBRs. After these stress conditions, the performance of the reactors were recovered when DO was around 2 mg L -1 . From that moment on, results showed that TCS addition implied a reduction of the adenosine triphosphate (ATP) production, which implied a decrease in the sludge production. In spite of this reduction, the SBRs performances did not decay due to the increase in the global MHEA. Additionally, the sludge reduction was enhanced by the increase of the F/M ratio, achieving 28% and 60% of reduction for the low and the high F/M ratio, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

A modified oxic-settling-anaerobic activated sludge process using gravity thickening for excess sludge reduction

NASA Astrophysics Data System (ADS)

Wang, Jun; Li, Shi-Yu; Jiang, Feng; Wu, Ke; Liu, Guang-Li; Lu, Hui; Chen, Guang-Hao

2015-09-01

Oxic-settling-anaerobic process (OSA) was known as a cost-effective way to reduce the excess sludge production with simple upgrade of conventional activated sludge process (CAS). A low oxidation-reduction potential (ORP) level was the key factor to sludge decay and lysis in the sludge holding tank of the OSA process. However, the ORP control with nitrogen purge or chemical dosing in the OSA process would induce extra expense and complicate the operation. Hence, in this study, a sludge holding tank using gravity thickening was applied to OSA process to reduce the excess sludge production without any ORP control. Results showed that the modified OSA process not only reduced the excess sludge production effectively but also improved the sludge settleability without affected the treatment capacity. The reduction of the excess sludge production in the modified OSA process resulted from interactions among lots of factors. The key element of the process was the gravity thickening sludge holding tank.

Enteric bacteria in aerobically digested sludge.

PubMed Central

Farrah, S R; Bitton, G

1984-01-01

Indicator bacteria, Salmonella spp., and total aerobic bacteria were determined in samples of undigested sludge and sludge that had been treated by one or two stages of aerobic digestion. Aerobic sludge digestion reduced the level of indicator bacteria by 1 to 2 log10 per g. The level of Salmonella spp. was also reduced during aerobic treatment of sludge. In general, aerobic treatment of sludge reduced, but did not eliminate, indicator bacteria and Salmonella spp. PMID:6721492

Petroleum sludge treatment and reuse for cement production as setting retarder

NASA Astrophysics Data System (ADS)

Aeslina, A. K.; Ali, B.

2017-05-01

Petroleum sludge is a dangerous waste that needs to be treated to avoid any contamination of soil and groundwater due to its disposal. As an attempt to treat this waste, it has been incorporated into cement production as substitution for gypsum. As results, 5% of petroleum sludge has shown effective results and could play the same role of gypsum in delaying the flash setting of cement clinker.

Evaluation of the accessibility of CCA metals in liquefied CCA-treated wood sludge for recovery and reuse

Treesearch

Hui Pan; Todd F. Shupe; Chung-Yun Hse

2009-01-01

CCA-treated wood was liquefied with polyethylene glycol/glycerin and sulfuric acid. The heavy metals were precipitated by Ca(OH)2 from liquefied CCA-treated wood. The original CCA-treated wood and precipitated wood sludge were fractionated by a modified BCR (Community Bureau of Reference) sequential extraction procedure. The purpose of the BCR...

Technology Assessment Report - Aqueous Sludge Gasification Technologies

EPA Science Inventory

Sludge production in the United States is increasing with an increase in population. An estimated 7.2 million dry tons of treated and tested sewage sludge was generated in 2004 and 4.1 million tons of paper mill sludge was produced in 1995. Consequently, there is an increased ne...

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

PubMed

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

2012-06-01

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

Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants.

PubMed

Pan, Yuting; Ye, Liu; van den Akker, Ben; Ganigué Pagès, Ramon; Musenze, Ronald S; Yuan, Zhiguo

2016-02-02

"Sludge-drying lagoons" are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge.

A novel conversion of the groundwater treatment sludge to magnetic particles for the adsorption of methylene blue.

PubMed

Zhu, Suiyi; Fang, Shuai; Huo, Mingxin; Yu, Yang; Chen, Yu; Yang, Xia; Geng, Zhi; Wang, Yi; Bian, Dejun; Huo, Hongliang

2015-07-15

Iron sludge, produced from filtration and backwash of groundwater treatment plant, has long been considered as a waste for landfill. In this study, iron sludge was reused to synthesize Fe3O4 magnetic particles (MPs) by using a novel solvothermal process. Iron sludge contained abundant amounts of silicon, iron, and aluminum and did not exhibit magnetic properties. After treatment for 4h, the amorphous Fe in iron sludge was transformed into magnetite Fe3O4, which could be easily separated from aqueous solution with a magnet. The prepared particles demonstrated the intrinsic properties of soft magnetic materials and could aggregate into a size of 1 μm. MPs treated for 10h exhibited excellent magnetic properties and a saturation magnetization value of 9 emu/g. The obtained particles presented the optimal adsorption of methylene blue under mild conditions, and the maximum adsorption capacity was 99.4 mg/g, which was higher than that of granular active carbon. The simple solvothermal method can be used to prepare Fe3O4 MPs from iron sludge, and the products could be applied to treatment of dyeing wastewater. Copyright © 2015. Published by Elsevier B.V.

Sludge-Treated Coal Mine Spoils Increase Heavy metals in Cover Crops

Treesearch

F. C. McBride; C. Chavengsaksongkram; D. H. Urie

1977-01-01

Four species of forage were grown in a greenhouse on acid strip mine spoil treated with municipal sewage sludge. Foliar levels of heavy metals exceeded those recommended for animal consumption. No plant toxicity symptoms were evident.

Inhibitory effects of toxic compounds on nitrification process for cokes wastewater treatment.

PubMed

Kim, Young Mo; Park, Donghee; Lee, Dae Sung; Park, Jong Moon

2008-04-15

Cokes wastewater is one of the most toxic industrial effluents since it contains high concentrations of toxic compounds such as phenols, cyanides and thiocyanate. Although activated sludge process has been adapted to treat this wastewater, nitrification process has been occasionally upset by serious inhibitory effects of toxic compounds. In this study, therefore, we examined inhibitory effects of ammonia, thiocyanate, free cyanide, ferric cyanide, phenol and p-cresol on nitrification in an activated sludge system, and then correlated their threshold concentrations with the full-scale pre-denitrification process for treating cokes wastewater. Ammonia below 350 mg/L did not cause substrate inhibition for nitrifying bacteria. Thiocyanate above 200mg/L seemed to inhibit nitrification, but it was due to the increased loading of ammonia produced from its biodegradation. Free cyanide above 0.2mg/L seriously inhibited nitrification, but ferric cyanide below 100mg/L did not. Phenol and p-cresol significantly inhibited nitrification above 200 mg/L and 100mg/L, respectively. Meantime, activated carbon was added to reduce inhibitory effects of phenol and free cyanide.

Feedforward neural network model estimating pollutant removal process within mesophilic upflow anaerobic sludge blanket bioreactor treating industrial starch processing wastewater.

PubMed

Antwi, Philip; Li, Jianzheng; Meng, Jia; Deng, Kaiwen; Koblah Quashie, Frank; Li, Jiuling; Opoku Boadi, Portia

2018-06-01

In this a, three-layered feedforward-backpropagation artificial neural network (BPANN) model was developed and employed to evaluate COD removal an upflow anaerobic sludge blanket (UASB) reactor treating industrial starch processing wastewater. At the end of UASB operation, microbial community characterization revealed satisfactory composition of microbes whereas morphology depicted rod-shaped archaea. pH, COD, NH 4 + , VFA, OLR and biogas yield were selected by principal component analysis and used as input variables. Whilst tangent sigmoid function (tansig) and linear function (purelin) were assigned as activation functions at the hidden-layer and output-layer, respectively, optimum BPANN architecture was achieved with Levenberg-Marquardt algorithm (trainlm) after eleven training algorithms had been tested. Based on performance indicators such the mean squared errors, fractional variance, index of agreement and coefficient of determination (R 2 ), the BPANN model demonstrated significant performance with R 2 reaching 87%. The study revealed that, control and optimization of an anaerobic digestion process with BPANN model was feasible. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbial dynamics in anaerobic digestion reactors for treating organic urban residues during the start-up process.

PubMed

Alcántara-Hernández, R J; Taş, N; Carlos-Pinedo, S; Durán-Moreno, A; Falcón, L I

2017-06-01

Anaerobic digestion of organic residues offers economic benefits via biogas production, still methane (CH 4 ) yield relies on the development of a robust microbial consortia for adequate substrate degradation, among other factors. In this study, we monitor biogas production and changes in the microbial community composition in two semi-continuous stirred tank reactors during the setting process under mesophilic conditions (35°C) using a 16S rDNA high-throughput sequencing method. Reactors were initially inoculated with anaerobic granular sludge from a brewery wastewater treatment plant, and gradually fed organic urban residues (4·0 kg VS m -3  day -1 ) . The inocula and biomass samples showed changes related to adaptations of the community to urban organic wastes including a higher relative proportion of Clostridiales, with Ruminococcus spp. and Syntrophomonas spp. as recurrent species. Candidatus Cloacamonas spp. (Spirochaetes) also increased from ~2·2% in the inoculum to >10% in the reactor biomass. The new community consolidated the cellulose degradation and the propionate and amino acids fermentation processes. Acetoclastic methanogens were more abundant in the reactor, where Methanosaeta spp. was found as a key player. This study demonstrates a successful use of brewery treatment plant granular sludge to obtain a robust consortium for methane production from urban organic solid waste in Mexico. This study describes the selection of relevant bacteria and archaea in anaerobic digesters inoculated with anaerobic granular sludge from a brewery wastewater treatment plant. Generally, these sludge granules are used to inoculate reactors digesting organic urban wastes. Though, it is still not clearly understood how micro-organisms respond to substrate variations during the reactor start-up process. After feeding two reactors with organic urban residues, it was found that a broader potential for cellulose degradation was developed including Bacteroidetes, Firmicutes and Spirochaetes. These results clarify the bacterial processes behind new reactors establishment for treating organic wastes in urban areas. © 2017 The Society for Applied Microbiology.

The manufacture and use of sludge test materials for R and D purposes in the treatment and processing of magnox based sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blackburn, D.R.; Thompson, E.J.

2013-07-01

Among the Intermediate Level Waste materials in store and awaiting treatment and processing in the UK are quantities of magnesium hydroxide sludge. This sludge is a product of radioactive Magnox Swarf which arose from the de-canning of used magnox fuel element rods. As the Swarf was stored underwater, a corrosion reaction occurred over the course of time between the magnox and the water resulting in a magnesium hydroxide based sludge. The differing conditions and materials present in the various storage areas means that the sludge can range in consistency from that of a slurry through to a thick clay. Sludgemore » test materials are required to underpin and validate the research and development equipment and processes that are to be used to treat the waste material. Necessary restrictions imposed on the sampling and testing of the radioactive waste means that the available data on the properties and behaviour of the sludge is limited. The raw materials used to create the sludge test materials are based upon magnesium hydroxide so that as far as possible the chemical behaviour will be similar to that of the waste material. The most representative sludge test material is manufactured by the corrosion of non-radioactive magnox or magnesium. However, time constraints make it impractical to supply this material in sufficient quantities for full scale validation trials. An alternative is to use sludge manufactured from commercially available magnesium hydroxide. The particle shape of commercially available materials differs from corrosion product magnesium hydroxide which means that properties such as the rheological behaviour cannot be replicated. Nevertheless, valuable trial data can be obtained, giving a greater degree of confidence in the waste treatment process than would be possible if only the more representative but less available corrosion product materials were to be used. Key test material parameters used in the trials have been identified as the particle size distribution and the sludge thickness (measured as yield shear strength). Other properties including cohesion, adhesion and rheological behaviour are also considered. The use of different mixers for sludge manufacture has the potential to affect the behavioural properties and a brief description of each of these mixers is included. The scale of mixing has been found to make a significant difference to the ageing. A chemical impurity in the commercially available materials has been successfully exploited, so that sludge mixed at comparatively low yield shear strengths can thicken into the consistency of clay. This aids manufacture and allows large quantities of thick material to be produced relatively easily. (authors)« less

Relative effectiveness of sewage sludge as a nitrogen fertilizer for tall fescue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiemnec, G.L.; Jackson, T.L.; Hemphill, D.D. Jr.

Sewage sludge application rates on grasses are mainly determined by N availability and concentration of toxic metals in sludge. The exact availability of N in sludge is difficult to predict. A 3-yr study was conducted to determine which sludge rates would give yields of tall fescue (Festuca arundinacea Shreb. Alta) comparable to yields obtained from inorganic N application. Sludge and NH/sub 4/NO/sub 3/ were surface applied at annual rates of 0, 110, 220, 440, and 880 (sludge only) kg N/ha. Dry matter yield of tall fescue from sludge-treated soils was 36, 56, and 50% of that on NH/sub 4/NO/sub 3/-treatedmore » soils for 1976, 1977, and 1978, respectively. Sludge was 27, 41, and 44% as effective as NH/sub 4/NO/sub 3/ as a source of available N in 1976, 1977, and 1978, respectively. Ammonium-N in the sewage sludge apparently provided most of the available N for fescue growth. Concentrations of Zn, Cd, and Cu were higher and Mn lower in tall fescue grown on sludge-treated soil with NH/sub 4/NO/sub 3/ and usually increased toward the end of the growing season. However, plant concentrations of these heavy metals never reached toxic levels at any time. Sewage sludge was an effective and safe nutrient source for tall fescue.« less

Waste Resources Utilization Program. Progress report, period ending September 30, 1975

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1975-12-01

The purpose of the Waste Resources Utilization Program is to develop a technology to constructively couple two major environmental problems, disposition of human and nuclear waste, in an attempt to provide a framework in which both will become useful resources. Sludge treated with thermoradiation offers considerable potential for use as a fertilizer in agriculture or a soil conditioner for land reclamation free of the serious potential health hazards associated with conventional methods of land disposal. In addition, the very real possibility exists that treated sludge may provide a low-cost substitute for high-nutritional components in ruminant diets. The liter size flow-throughmore » system is put into operation for the first time and provides sufficient quantities of treated sludge for good biological analysis and to start the animal feeding program at New Mexico State University. Approximately 3800 gal of sewage sludge were thermoradiation-treated with the system. The sludge was exposed to approximately 150 krads of gamma radiation at a temperature of 65$sup 0$C. The treated sludge was monitored for elimination of total coliforms and fecal strep. No fecal strep bacteria were found in 400 sample plates; three contained coliform growth. An intensive study of poliovirus inactivation in sewage sludge was completed this quarter. Source efficiencies were calculated for possible modification to the WESF capsule which would consist of inserting a hollow tube in the center of the capsule. This was proposed as a simple modification to the standard WESF capsule to reduce the self-shielding characteristic of the cesium. The calculations showed little or no advantage of adding the center tube. (TFD)« less

Characterization of Industrial Wastewater Sludge in Oman from Three Different Regions and Recommendations for Alternate Reuse Applications.

PubMed

Baawain, Mahad S; Al-Jabri, Mohsin; Choudri, B S

2015-11-01

Domestic and industrial wastewaters are mostly treated by biological process such as activated sludge, aerobic pond, and anaerobic treatment. This study focuses on characterizing the quality of sewage sludge in the Sultanate of Oman chosen from three industrial sewage treatment plants (STPs): Rusayl Industrial Estate (RSL.IE); Sohar Industrial Estate (SIE); and Raysut Industrial Estate (RIE). Samples of recycled activated sludge (RAS) and wasted activated sludge (WAS) were collected over a period of 12 months across above mentioned STPs. Parameters analyzed are electrical conductivity (EC), potential of hydrogen (pH), cations, anions and volatile content (VC). The obtained values for pH and EC were low for both RAS and WAS samples, except EC values of RIE that was more than 1000 μS/cm. The range of VC percentages in RAS and WAS samples were 44 to 86% and 41 to 77%, respectively. The measured values for chloride, sulfate, nitrate and phosphate were higher than the other anions. The average values of the cations in RAS and WAS samples were within the Omani Standards, suitable for the re-use of sludge in agriculture except for Cd in RSL.IE. The study recommends that a regular maintenance should be performed at the studied STPs to prevent any accumulation of some harmful substances, which may affect the sludge quality, and the sludge drying beds should be large enough to handle the produced sludge for better management.

Characterization of Industrial Wastewater Sludge in Oman from Three Different Regions and Recommendations for Alternate Reuse Applications

PubMed Central

BAAWAIN, Mahad S.; AL-JABRI, Mohsin; CHOUDRI, B.S.

2015-01-01

Background: Domestic and industrial wastewaters are mostly treated by biological process such as activated sludge, aerobic pond, and anaerobic treatment. This study focuses on characterizing the quality of sewage sludge in the Sultanate of Oman chosen from three industrial sewage treatment plants (STPs): Rusayl Industrial Estate (RSL.IE); Sohar Industrial Estate (SIE); and Raysut Industrial Estate (RIE). Methods: Samples of recycled activated sludge (RAS) and wasted activated sludge (WAS) were collected over a period of 12 months across above mentioned STPs. Parameters analyzed are electrical conductivity (EC), potential of hydrogen (pH), cations, anions and volatile content (VC). Results: The obtained values for pH and EC were low for both RAS and WAS samples, except EC values of RIE that was more than 1000 μS/cm. The range of VC percentages in RAS and WAS samples were 44 to 86% and 41 to 77%, respectively. The measured values for chloride, sulfate, nitrate and phosphate were higher than the other anions. Conclusion: The average values of the cations in RAS and WAS samples were within the Omani Standards, suitable for the re-use of sludge in agriculture except for Cd in RSL.IE. The study recommends that a regular maintenance should be performed at the studied STPs to prevent any accumulation of some harmful substances, which may affect the sludge quality, and the sludge drying beds should be large enough to handle the produced sludge for better management. PMID:26744704

DEMONSTRATION BULLETIN: IN SITU VITRIFICATION - GEOSAFE CORPORATION

EPA Science Inventory

in Situ Vitrification (ISV) is designed to treat soils, sludges, sediments, and mine tailings contaminated with organic and inorganic compounds. The process uses electrical current to heat (mett) and vitrify the soil in place. Organic contaminants are decomposed by the extreme h...

Toxicity assessment of untreated/treated electroplating sludge using human and plant bioassay.

PubMed

Orescanin, Visnja; Durgo, Ksenija; Mikelic, Ivanka Lovrencic; Halkijevic, Ivan; Kuspilic, Marin

2018-04-30

The purpose of this work was to assess the risk to the environment arising from the electroplating sludge from both chemical and toxicological point of view. Both approaches were used for the assessment of the treatment efficiency which consisted of CaO based solidification followed by thermal treatment at 400°C. The elemental composition was determined in the bulk samples and the leachates of untreated sludge. The toxicity of the leachate was determined using two human colorectal adenocarcinoma cell lines (Caco-2 and SW 480) and Hordeum vulgare L. based plant bioassay. The same toxicity tests were employed to the leachate of the treated sludge. Untreated sludge showed extremely high cytotoxic effect to both human and plant bio-system in dose-dependent manner. The percentages higher than 0.5% and 0.05% of the leachate caused significant cytotoxic effect on Caco-2 and SW 480 cells, respectively. The percentages of the leachate higher than 0.05% also showed significant toxic effect to H. vulgare L. bio-system with complete arrest of seed germination following the treatment with 100% to 5% of the leachate. The leachate of the treated sludge showed no toxicity to any of the test systems confirming the efficiency and justification of the employed procedures for the detoxification of electroplating sludge.

Innovative sludge pretreatment technology for impurity separation using micromesh.

PubMed

Mei, Xiaojie; Han, Xiaomeng; Zang, Lili; Wu, Zhichao

2018-05-23

In order to reduce the impacts on sludge treatment facilities caused by impurities such as fibers, hairs, plastic debris, and coarse sand, an innovative primary sludge pretreatment technology, sludge impurity separator (SIS), was proposed in this study. Non-woven micromesh with pore size of 0.40 mm was used to remove the impurities from primary sludge. Results of lab-scale tests showed that impurity concentration, aeration intensity, and channel gap were the key operation parameters, of which the optimized values were below 25 g/L, 0.8 m 3 /(m 2  min), and 2.5 cm, respectively. In the full-scale SIS with treatment capacity of 300 m 3 /day, over 88% of impurities could be removed from influent and the cleaning cycle of micromesh was more than 16 days. Economic analysis revealed that the average energy consumption was 1.06 kWh/m 3 treated sludge and operation cost was 0.6 yuan/m 3 treated sludge.

Behavior of cellulose-degrading bacteria in thermophilic anaerobic digestion process.

PubMed

Syutsubo, K; Nagaya, Y; Sakai, S; Miya, A

2005-01-01

Previously, we found that the newly isolated Clostridium sp. strain JC3 became the dominant cellulose-degrading bacterium in thermophilic methanogenic sludge. In the present study, the behavior of strain JC3 in the thermophilic anaerobic digestion process was investigated quantitatively by molecular biological techniques. A cellulose-degrading experiment was conducted at 55 degrees C with a 9.5 L of anaerobic baffled reactor having three compartments (Nos. 1, 2, 3). Over 80% of the COD input was converted into methane when 2.5 kgCOD m(-3) d(-1) was loaded for an HRT of 27 days. A FISH probe specific for strain JC3 was applied to sludge samples harvested from the baffled reactor. Consequently, the ratio of JC3 cells to DAPI-stained cells increased from below 0.5% (undetectable) to 9.4% (compartment 1), 13.1% (compartment 2) and 21.6% (compartment 3) at day 84 (2.5 kgCOD m(-3)d(-1)). The strain JC3 cell numbers determined by FISH correlated closely with the cellulose-degrading methanogenic activities of retained sludge. A specific primer set targeting the cellulase gene (cellobiohydrolaseA: cbhA) of strain JC3 was designed and applied to digested sludge for treating solid waste such as coffee grounds, wastepaper, garbage, cellulose and so on. The strain JC3 cell numbers determined by quantitative PCR correlated closely with the cellulose-sludge loading of the thermophilic digester. Strain JC3 is thus important in the anaerobic hydrolysis of cellulose in thermophilic anaerobic digestion processes.

The demonstration of a novel sulfur cycle-based wastewater treatment process: sulfate reduction, autotrophic denitrification, and nitrification integrated (SANI®) biological nitrogen removal process.

PubMed

Lu, Hui; Wu, Di; Jiang, Feng; Ekama, George A; van Loosdrecht, Mark C M; Chen, Guang-Hao

2012-11-01

Saline water supply has been successfully practiced for toilet flushing in Hong Kong since 1950s, which saves 22% of freshwater in Hong Kong. In order to extend the benefits of saline water supply into saline sewage management, we have recently developed a novel biological organics and nitrogen removal process: the Sulfate reduction, Autotrophic denitrification, and Nitrification Integrated (SANI®) process. The key features of this novel process include elimination of oxygen demand in organic matter removal and production of minimal sludge. Following the success of a 500-day lab-scale trial, this study reports a pilot scale evaluation of this novel process treating 10 m(3) /day of 6-mm screened saline sewage in Hong Kong. The SANI® pilot plant consisted of a sulfate reduction up-flow sludge bed (SRUSB) reactor, an anoxic bioreactor for autotrophic denitrification and an aerobic bioreactor for nitrification. The plant was operated at a steady state for 225 days, during which the average removal efficiencies of both chemical oxygen demand (COD) and total suspended solids (TSS) at 87% and no excess sludge was purposefully withdrawn. Furthermore, a tracer test revealed 5% short circuit flow and a 34.6% dead zone in the SRUSB, indicating a good possibility to further optimize the treatment capacity of the process for full-scale application. Compared with conventional biological nitrogen removal processes, the SANI® process reduces 90% of waste sludge, which saves 35% of the energy and reduces 36% of fossil CO(2) emission. The SANI® process not only eliminates the major odor sources originating from primary treatment and subsequent sludge treatment and disposal during secondary saline sewage treatment, but also promotes saline water supply as an economic and sustainable solution for water scarcity and sewage treatment in water-scarce coastal areas. Copyright © 2012 Wiley Periodicals, Inc.

Laboratory measurements of radiance and reflectance spectra of dilute secondary-treated sewage sludge

NASA Technical Reports Server (NTRS)

Witte, W. G.; Usry, J. W.; Whitlock, C. H.; Gurganus, E. A.

1977-01-01

The National Aeronautics and Space Administration (NASA), in cooperation with the Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA), conducted a research program to evaluate the feasibility of remotely monitoring ocean dumping of waste products such as acid and sewage sludge. One aspect of the research program involved the measurements of upwelled spectral signatures for sewage-sludge mixtures of different concentrations in an 11600-liter tank. This paper describes the laboratory arrangement and presents radiance and reflectance spectra in the visible and near-infrared ranges for concentrations ranging from 9.7 to 180 ppm of secondary-treated sewage sludge mixed with two types of base water. Results indicate that upwelled radiance varies in a near-linear manner with concentration and that the sludge has a practically flat signal response between 420 and 970 nm. Reflectance spectra were obtained for the sewage-sludge mixtures at all wavelengths and concentrations.

Combined quantity management and biological treatment of sludge liquor at Hamburg's wastewater treatment plants--first experience in operation with the Store and Treat process.

PubMed

Laurich, F

2004-01-01

Store and Treat (SAT) is a new concept for the management of ammonium-rich process waste waters at wastewater treatment plants. It combines the advantages of quantity management and separate biological treatment, whereby both operations are carried out in the same tank. Now the first full-scale application of that method was realized in Hamburg. As first experience shows the process can help to increase nitrogen removal and to reduce energy consumption.

Sludge accumulation and conversion to methane in a septic tank treating domestic wastewater or black water.

PubMed

Elmitwalli, Tarek

2013-01-01

Although the septic tank is the most applied on-site system for wastewater pre-treatment, limited research has been performed to determine sludge accumulation and biogas production in the tank. Therefore a dynamic mathematical model based on the Anaerobic Digestion Model No. 1 (ADM1) was developed for anaerobic digestion of the accumulated sludge in a septic tank treating domestic wastewater or black water. The results showed that influent chemical oxygen demand (COD) concentration and hydraulic retention time (HRT) of the tank mainly control the filling time with sludge, while operational temperature governs characteristics of the accumulated sludge and conversion to methane. For obtaining stable sludge and high conversion, the tank needs to be operated for a period more than a year without sludge wasting. Maximum conversion to methane in the tank is about 50 and 60% for domestic wastewater and black water, respectively. The required period for sludge wasting depends on the influent COD concentration and the HRT, while characteristics of the wasted sludge are affected by operational temperature followed by the influent COD concentration and the HRT. Sludge production from the tank ranges between 0.19 to 0.22 and 0.13 to 0.15 L/(person.d), for the domestic wastewater and black water, respectively.

The use of waste mussel shells for the adsorption of dyes and heavy metals

NASA Astrophysics Data System (ADS)

Papadimitriou, Chrysi A.; Krey, Grigorios; Stamatis, Nikolaos; Kallaniotis, Argyris

2016-04-01

Mussel culture is very important sector of the Greek agricultural economy. The majority of mussel culture activities take place in the area of Central Macedonia, Greece, 60% of total mussel production in Greece producing almost 12 tons of waste mussels shells on a daily basis. Currently there is no legislation concerning the disposal of mussel shells. In the present study the waste shells were used for the removal of dyes and heavy metals from aqueous solutions while powdered mussel shells were added in activated sludge processes for the removal of hexavalent chromium. Mussel shells were cleaned, dried and then crushed in order to form a powder. Powdered mussels shells were used in standard adsorption experiments for the removal of methylene blue and methyl red as well as for the removal of Cr (VI), Cd and Cu. Moreover the powdered mussel shells were added in laboratory scale activated sludge reactors treating synthetic wastewater with hexavalent chromium, in order investigate the effects in activated sludge processes and their potential attribution to the removal of hexavalent chromium. Adsorption experiments indicated almost 100% color removal, while adsorption was directly proportional to the amount of powdered mussel shells added in each case. The isotherms calculated for the case of methylene blue indicated similar adsorption capacity and properties to those of the commercially available activated carbon SAE 2, Norit. High removal efficiencies were observed for the metals, especially in the case of chromium and copper. The addition of powdered mussel shells in the activated sludge processes enhanced the removal of chromium and phosphorus, while enabled the formation of heavier activated sludge flocs and thus enhanced the settling properties of the activated sludge.

An integrated AMBBR and IFAS-SBR process for municipal wastewater treatment towards enhanced energy recovery, reduced energy consumption and sludge production.

PubMed

Gu, Jun; Xu, Guangjing; Liu, Yu

2017-03-01

The conventional activated sludge (CAS) process has been widely employed for wastewater treatment for more than one hundred years. Recently, more and more concerns have been raised on the CAS process due to its high energy consumption and production of huge amount of waste activated sludge, which are inevitably linked to the issue of environmental sustainability and global climate change. Facing to such emerging and challenging situation, this study reported a novel A-B process in which an anaerobic moving bed biofilm reactor (AMBBR) served a lead A-stage for COD capture towards biogas production and an integrated fixed-biofilm and activated sludge sequencing batch reactor (IFAS-SBR) was employed as B-stage for biological nitrogen removal. Results showed that about 85% of wastewater COD was removed in the steady-state AMBBR with a total energy production rate of 0.28 kWh/m 3 wastewater treated, while 85% of N-removal was achieved when the stable nitrite shunt was established in the IFAS-SBR. Moreover, 90% of dissolved methane in the AMBBR effluent could be removed by the proposed flash chamber at the lower energy demand of 0.12 kWh/m 3 which could be offset by the potential energy harvested from produced methane. Compared to the CAS process, the production of waste sludge was reduced by about 75% in the proposed A-B process due to the efficient COD capture at the A-stage, leading to significant energy savings from aeration for COD oxidation and post-treatment of waste sludge at the B-stage. Consequently, this study offers in-depth insights into A-B process which should be considered as an ideal candidate for achieving the energy-neutral or even energy positive operation of a municipal wastewater treatment. Given the complex situation in A-B process, future study is needed to look into the system optimization towards the operational synergy between A- and B-stage in terms of energy recovery and nitrogen removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of cement on redistribution of trace metals and dissolution of organics in sewage sludge and its inorganic waste-amended products.

PubMed

Lim, T T; Chu, J; Goi, M H

2006-01-01

The suitability of using cement-stabilized sludge products as artificial soils in earth works was evaluated. The sludge products investigated were cemented sludge, cement-treated clay-amended sludge (SS+MC), and cement-treated copper slag-amended sludge (SS+CS). The leachability of lead (Pb), zinc (Zn), copper (Cu), and chromium (Cr) were assessed using the sequential extraction technique, toxicity characteristic leaching procedure (TCLP), NEN 7341 availability test, and column leaching test. The results indicated that Zn leachability was reduced in all the cement-stabilized sludge products. In contrast, Cu was transferred from the organic fraction to the readily leachable phases in the cement-stabilized sludge products and therefore exhibited increased leachability. The increased Cu leachability could be attributed to dissolution of humic substances in the sludge as a result of elevated pH. Good correlation between dissolved organic carbon (DOC) and heavy metal leaching from the cement-stabilized sludge products was observed in the column leaching experiment. Even with a cement percentage as small as 12.5%, calcium silicate hydrate (C-S-H) was formed in the SS+MC and SS+CS products. Inclusion of the marine clay in the SS+MC products could reduce the leaching potentials of Zn, and this was the great advantage of the marine clay over the copper slag for sludge amendment.

PROCESS DESIGN MANUAL: SURFACE DISPOSAL OF SEWAGE SLUDGE AND DOMESTIC SEPTAGE

EPA Science Inventory

Human domestic activities generate wastewater that is piped into municipal sewer systems, underground septic tanks, or portable sanitation devices. Wastewater in municipal systems is treated before being discharged into the environment, as required under the Clean Water Act. This...

Greenhouse gases emissions accounting for typical sewage sludge digestion with energy utilization and residue land application in China.

PubMed

Niu, Dong-jie; Huang, Hui; Dai, Xiao-hu; Zhao, You-cai

2013-01-01

About 20 million tonnes of sludge (with 80% moisture content) is discharged by the sewage treatment plants per year in China, which, if not treated properly, can be a significant source of greenhouse gases (GHGs) emissions. Anaerobic digestion is a conventional sewage sludge treatment method and will continue to be one of the main technologies in the following years. This research has taken into consideration GHGs emissions from typical processes of sludge thickening+anaerobic digestion+dewatering+residue land application in China. Fossil CO(2), biogenic CO(2), CH(4,) and avoided CO(2) as the main objects is discussed respectively. The results show that the total CO(2)-eq is about 1133 kg/t DM (including the biogenic CO(2)), while the net CO(2)-eq is about 372 kg/t DM (excluding the biogenic CO(2)). An anaerobic digestion unit as the main GHGs emission source occupies more than 91% CO(2)-eq of the whole process. The use of biogas is important for achieving carbon dioxide emission reductions, which could reach about 24% of the total CO(2)-eq reduction. Copyright © 2012 Elsevier Ltd. All rights reserved.

Solidification of Dredged Sludge by Hydraulic Ash-Slag Cementitious Materials

NASA Astrophysics Data System (ADS)

Zhu, Shu-Jing; Qin, Ying; Hwang, Jiann-Yang

Solidification treatment is used to treat hazardous wastes for disposal and to remediate the contaminated land. It is an increasingly popular technology for redevelopment of brown fields since treated wastes can often be left on-site, which can improve the site's soil for subsequent construction. In order to find home for the dredged sludge from the Pearl River Estuary Channel in China, the potential uses of treated dredged sludge by solidification treatment as valuable structural fill was investigated. Structure fills were prepared under various formula and curing conditions. Modulus of elasticity was detemined at 7 days, 14 days and 28 days with different types of load application. Atterberg limit, compactibility and CBR values are reported. The relationship between the microstructure and engineering properties of treated sludge are examined. The results clearly show the technical benefits by stabilizing soft soils with Hydraulic ash-slag cementitious materials. XRD and DTA-TG tests were carried out on certain samples to characterize the hydraulic compounds formed.

Operational Test Report (OTR): On-Site Degradation of Oily Sludge in a Tenthousand Gallon Sequencing Batch Reactor at Navsta Pearl Harbor, HI

DTIC Science & Technology

2003-11-01

treated anaerobically . To accommodate the longer residence times needed to treat waste anaerobically , the capacity is often much larger than a...the receiving tank (T1), where it is diluted and run through a trash pump (P1) to produce a homogenous slurry. 3 Figure 1. Sequencing...blower provides air to the reactor and receiving tank. The trash pump is also used to transfer sludge to the reactor and to recirculate sludge in

ATAD control goals through the analysis of process variables and evaluation of quality, production and cost.

PubMed

Nájera, S; Gil-Martínez, M; Zambrano, J A

2015-01-01

The aim of this paper is to establish and quantify different operational goals and control strategies in autothermal thermophilic aerobic digestion (ATAD). This technology appears as an alternative to conventional sludge digestion systems. During the batch-mode reaction, high temperatures promote sludge stabilization and pasteurization. The digester temperature is usually the only online, robust, measurable variable. The average temperature can be regulated by manipulating both the air injection and the sludge retention time. An improved performance of diverse biochemical variables can be achieved through proper manipulation of these inputs. However, a better quality of treated sludge usually implies major operating costs or a lower production rate. Thus, quality, production and cost indices are defined to quantify the outcomes of the treatment. Based on these, tradeoff control strategies are proposed and illustrated through some examples. This paper's results are relevant to guide plant operators, to design automatic control systems and to compare or evaluate the control performance on ATAD systems.

40 CFR 98.350 - Definition of source category.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.350 Definition of source category. (a) This source category consists of anaerobic processes used to treat industrial wastewater and industrial wastewater treatment sludge at facilities that perform the operations listed in this paragraph. (1...

40 CFR 98.350 - Definition of source category.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.350 Definition of source category. (a) This source category consists of anaerobic processes used to treat industrial wastewater and industrial wastewater treatment sludge at facilities that perform the operations listed in this paragraph. (1...

40 CFR 98.350 - Definition of source category.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.350 Definition of source category. (a) This source category consists of anaerobic processes used to treat industrial wastewater and industrial wastewater treatment sludge at facilities that perform the operations listed in this paragraph. (1...

40 CFR 98.350 - Definition of source category.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.350 Definition of source category. (a) This source category consists of anaerobic processes used to treat industrial wastewater and industrial wastewater treatment sludge at facilities that perform the operations listed in this paragraph. (1...

Chemical state of chromium in sewage sludge ash based phosphorus-fertilisers.

PubMed

Vogel, Christian; Adam, Christian; Kappen, Peter; Schiller, Tara; Lipiec, Ewelina; McNaughton, Don

2014-05-01

Sewage sludge ash (SSA) based P-fertilisers were produced by thermochemical treatment of SSA with Cl-donors at approximately 1000°C. During this thermochemical process heavy metals are separated as heavy metal chlorides via the gas phase. Chromium cannot be separated under normal conditions. The risk of the development of toxic Cr(VI) during the thermochemical process was investigated. X-ray Absorption Spectroscopy measurements showed that SSA and thermochemically treated SSA with CaCl2, MgCl2 and NaCl contain Cr(III) compounds only. In contrast, treating SSA with elevated quantities of Na2CO3, to enhance the plant-availability of the phosphate phases of the fertiliser, developed approximately 10-15% Cr(VI). Furthermore, Raman microspectroscopy showed that using Mg-carbonate reduces the risk of a Cr(VI) development during thermochemical treatment. Additionally, leaching tests showed that only a Cr-water solubility>10% is an indicator for Cr(VI) in SSA based P-fertilisers. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

PubMed

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 application on the soil of sludge stabilized by liming or anaerobic digestion.

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

PubMed

Yoon, Seong-Hoon; Lee, Sangho

2005-09-01

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

Valuation of OSA process and folic acid addition as excess sludge minimization alternatives applied in the activated sludge process.

PubMed

Martins, C L; Velho, V F; Ramos, S R A; Pires, A S C D; Duarte, E C N F A; Costa, R H R

2016-01-01

The aim of this study was to investigate the ability of the oxic-settling-anaerobic (OSA)-process and the folic acid addition applied in the activated sludge process to reduce the excess sludge production. The study was monitored during two distinct periods: activated sludge system with OSA-process, and activated sludge system with folic acid addition. The observed sludge yields (Yobs) were 0.30 and 0.08 kgTSS kg(-1) chemical oxygen demand (COD), control phase and OSA-process (period 1); 0.33 and 0.18 kgTSS kg(-1) COD, control phase and folic acid addition (period 2). The Yobs decreased by 73 and 45% in phases with the OSA-process and folic acid addition, respectively, compared with the control phases. The sludge minimization alternatives result in a decrease in excess sludge production, without negatively affecting the performance of the effluent treatment.

Growth, physiology and yield of durum wheat (Triticum durum) treated with sewage sludge under water stress conditions

PubMed Central

Boudjabi, Sonia; Kribaa, Mohammed; Chenchouni, Haroun

2015-01-01

In arid and semi-arid areas, low soil fertility and water deficit considerably limit crop production. The use of sewage sludge as an organic amendment could contribute to the improvement of soil fertility and hence the agronomic production. The study aims to highlight the behaviour of durum wheat to the application of sewage sludge associated with water stress. The assessment focused on morphophysiological parameters of the wheat plant and yield. Under greenhouse conditions, the variety Mohamed Ben Bachir was treated by four water stress levels (100 %, 80 %, 50 % and 30 %). Each stress level comprised five fertilizer treatments: 20, 50 and 100 t/ha of dry sludge, 35 kg/ha of urea, and a control with no fertilization. Results revealed a significant loss in water content and chlorophyll a in leaves. Water stress negatively affected the development of wheat plants by reducing significantly seed yield, leaf area and biomass produced. Plant’s responses to water stress manifested by an accumulation of proline and a decrease in total phosphorus. However, the increasing doses of sewage sludge limited the effect of water stress. Our findings showed an increase in the amount of chlorophyll pigments, leaf area, total phosphorus, biomass and yield. In addition, excessive accumulation of proline (1.11 ± 1.03 µg/g DM) was recorded as a result of the high concentration of sludge (100 t/ha DM). The application of sewage sludge is beneficial for the wheat crop, but the high accumulation of proline in plants treated with high dose of sludge suggests to properly consider this fact. The application of sludge should be used with caution in soils where water is limited. Because the combined effect of these two factors could result in a fatal osmotic stress to crop development. PMID:26417365

Dynamics of two methanogenic microbiomes incubated in polycyclic aromatic hydrocarbons, naphthenic acids, and oil field produced water.

PubMed

Oko, Bonahis J; Tao, Yu; Stuckey, David C

2017-01-01

Oil field produced water (OFPW) is widely produced in large volumes around the world. Transforming the organic matter in OFPW into bioenergy, such as biomethane, is one promising way to sustainability. However, OFPW is difficult to biologically degrade because it contains complex compounds such as naphthenic acids (NAs), or polycyclic aromatic hydrocarbons (PAHs). Although active microbial communities have been found in many oil reservoirs, little is known about how an exotic microbiome, e.g. the one which originates from municipal wastewater treatment plants, would evolve when incubated with OFPW. In this study, we harvested methanogenic biomass from two sources: a full-scale anaerobic digester (AD) treating oil and gas processing wastewater (named O&G sludge), and from a full-scale AD reactor treating multiple fractions of municipal solid wastes (named MS, short for mixed sludge). Both were incubated in replicate microcosms fed with PAHs, NAs, or OFPW. The results showed that the PAHs, NAs, and OFPW feeds could rapidly alter the methanogenic microbiomes, even after 14 days, while the O&G sludge adapted faster than the mixed sludge in all the incubations. Two rarely reported microorganisms, a hydrogenotrophic methanogen Candidatus methanoregula and a saccharolytic fermenter Kosmotoga , were found to be prevalent in the PAHs and OFPW microcosms, and are likely to play an important role in the syntrophic degradation of PAHs and OFPW, cooperating with methanogens such as Methanoregula, Methanosarcina, or Methanobacterium . The dominant phyla varied in certain patterns during the incubations, depending on the biomass source, feed type, and variation in nutrients. The sludge that originated from the oil and gas processing wastewater treatment (O&G) reactor adapted faster than the one from municipal solid waste reactors, almost certainly because the O&G biomass had been "pre-selected" by the environment. This study reveals the importance of biomass selection for other crude oil-waste-related bioengineering studies, such as bioaugmentation and bioremediation.

Greenhouse gases emissions accounting for typical sewage sludge digestion with energy utilization and residue land application in China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu Dongjie, E-mail: niudongjie@tongji.edu.cn; UNEP-Tongji Institute of Environment for Sustainable Development, 1239 Siping Road, Shanghai 200092; Huang Hui

2013-01-15

Highlights: Black-Right-Pointing-Pointer GHGs emissions from sludge digestion + residue land use in China were calculated. Black-Right-Pointing-Pointer The AD unit contributes more than 97% of total biogenic GHGs emissions. Black-Right-Pointing-Pointer AD with methane recovery is attractive for sludge GHGs emissions reduction. - Abstract: About 20 million tonnes of sludge (with 80% moisture content) is discharged by the sewage treatment plants per year in China, which, if not treated properly, can be a significant source of greenhouse gases (GHGs) emissions. Anaerobic digestion is a conventional sewage sludge treatment method and will continue to be one of the main technologies in the followingmore » years. This research has taken into consideration GHGs emissions from typical processes of sludge thickening + anaerobic digestion + dewatering + residue land application in China. Fossil CO{sub 2}, biogenic CO{sub 2}, CH{sub 4,} and avoided CO{sub 2} as the main objects is discussed respectively. The results show that the total CO{sub 2}-eq is about 1133 kg/t DM (including the biogenic CO{sub 2}), while the net CO{sub 2}-eq is about 372 kg/t DM (excluding the biogenic CO{sub 2}). An anaerobic digestion unit as the main GHGs emission source occupies more than 91% CO{sub 2}-eq of the whole process. The use of biogas is important for achieving carbon dioxide emission reductions, which could reach about 24% of the total CO{sub 2}-eq reduction.« less

Sewage sludge treatment system

NASA Technical Reports Server (NTRS)

Kalvinskas, John J. (Inventor); Mueller, William A. (Inventor)

1976-01-01

Raw sewage may be presently treated by mixing screened raw sewage with activated carbon. The mixture is then allowed to stand in a first tank for a period required to settle the suspended matter to the bottom of the tank as a sludge. Thereafter, the remaining liquid is again mixed with activated carbon and the mixture is transferred to a secondary settling tank, where it is permitted to stand for a period required for the remaining floating material to settle as sludge and for adsorption of sewage carbon as well as other impurities to take place. The sludge from the bottom of both tanks is removed and pyrolyzed to form activated carbon and ash, which is mixed with the incoming raw sewage and also mixed with the liquid being transferred from the primary to the secondary settling tank. It has been found that the output obtained by the pyrolysis process contains an excess amount of ash. Removal of this excess amount of ash usually also results in removing an excess amount of carbon thereby requiring adding carbon to maintain the treatment process. By separately pyrolyzing the respective sludges from the first and second settling tanks, and returning the separately obtained pyrolyzed material to the respective first and second tanks from which they came, it has been found that the adverse effects of the excessive ash buildup is minimized, the carbon yield is increased, and the sludge from the secondary tank can be pyrolyzed into activated carbon to be used as indicated many more times than was done before exhaustion occurs.

Improving alachlor biodegradability by ferrate oxidation.

PubMed

Zhu, Jian-Hang; Yan, Xi-Luan; Liu, Ye; Zhang, Bao

2006-07-31

Alachlor can be recalcitrant when present at high concentrations in wastewater. Ferrate oxidation was used as a pretreatment to improve its biodegradability and was evaluated by monitoring alachlor elimination and removal of COD(Cr) (chemical oxygen demand determined by potassium dichromate) during the oxidation process up to a value compatible with biological treatment. Ferrate oxidation resulted in elimination of alachlor followed by degradation of its intermediates. High pH suppressed alachlor removal and COD(Cr) removal due to the low redox potential of ferrate ions. Although alachlor can be totally eliminated within 10 min under optimized conditions (alachlor, 40 mg l(-1); ferrate:alachlor molar ratio, 2; and pH 7.0), its complete mineralization cannot be achieved by ferrate oxidation alone. Alachlor solution treated by ferrate for 10 min inhibited an up-flow biotreatment with activated sludge. The biodegradability of ferrate-pretreated solution improved when the treatment was increased to 20 min, at the point of which BOD(5)/COD(Cr) ratio of the treated solution was increased to 0.87 from 0.35 after 10 min treatment. Under optimized conditions, ferrate oxidation for 20 min resulted in total elimination of alachlor, partial removal of COD(Cr) and the ferrate-treated solution could be effectively treated by the up-flow activated sludge process.

Valorization of a pharmaceutical organic sludge through different composting treatments.

PubMed

Cucina, Mirko; Tacconi, Chiara; Sordi, Simone; Pezzolla, Daniela; Gigliotti, Giovanni; Zadra, Claudia

2018-04-01

Nowadays, the agricultural reuse of pharmaceutical sludge is still limited due to environmental and agronomic issues (e.g. low stabilization of the organic matter, phytotoxicity). The aim of the present study was to evaluate the characteristics of a pharmaceutical sludge derived from the daptomycin production and to study the possibility of improving its quality through composting. The pharmaceutical sludge showed high content of macronutrients (e.g. total Kjeldahl N content was 38 g kg -1 ), but it was also characterized by high salinity (7.9 dS m -1 ), phytotoxicity (germination index was 36.7%) and a low organic matter stabilization. Two different mixtures were prepared (mixture A: 70% sludge + 30% wood chips w/w, mixture B: 45% sludge + 45% wood chips + 10% cereal straw w/w) and treated through static composting using two different aeration systems: active and passive aeration. The mixtures resulted in the production of two different compost, and the evolution of process management parameters was different. The low total solids and organic matter content of mixture A led to the failure of the process. The addition of cereal straw in mixture B resulted in increased porosity and C/N ratio and, consequently, in an optimal development of the composting process (e.g. the final organic matter loss was 54.1% and 63.1% for the passively and actively aerated treatment, respectively). Both passively and actively aerated composting of mixture B improved the quality of the pharmaceutical sludge, by increasing its organic matter stabilization and removing phytotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radiation processing applications in the Czechoslovak water treatment technologies

NASA Astrophysics Data System (ADS)

Vacek, K.; Pastuszek, F.; Sedláček, M.

The regeneration of biologically clogged water wells by radiation proved to be a successful and economically beneficial process among other promising applications of ionizing radiation in the water supply technology. The application conditions and experience are mentioned. The potential pathogenic Mycobacteria occuring in the warm washing and bathing water are resistant against usual chlorine and ozone concentrations. The radiation sensitivity of Mycobacteria allowed to suggest a device for their destroying by radiation. Some toxic substances in the underground water can be efficiently degraded by gamma radiation directly in the wells drilled as a hydraulic barrier surrounding the contaminated land area. Substantial decrease of CN - concentration and C.O.D. value was observed in water pumped from such well equipped with cobalt sources and charcoal. The removing of pathogenic contamination remains to be the main goal of radiation processing in the water purification technologies. The decrease of liquid sludge specific filter resistance and sedimentation acceleration by irradiation have a minor technological importance. The hygienization of sludge cake from the mechanical belt filter press by electron beam appears to be the optimum application in the Czechoslovak conditions. The potatoes and barley crop yields from experimental plots treated with sludge were higher in comparison with using the manure. Biological sludge from the municipal and food industry water purification plants contains nutritive components. The proper hygienization is a necessary condition for using them as a livestock feed supplement. Feeding experiments with broilers and pigs confirmed the possibility of partial (e.g. 50%) replacement of soya-, bone- or fish flour in feed mixtures by dried sludge hygienized either by heat or by the irradiation.

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

PubMed

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.

Small hazardous waste generators in developing countries: use of stabilization/solidification process as an economic tool for metal wastewater treatment and appropriate sludge disposal.

PubMed

Silva, Marcos A R; Mater, Luciana; Souza-Sierra, Maria M; Corrêa, Albertina X R; Sperb, Rafael; Radetski, Claudemir M

2007-08-25

The aim of this study was to propose a profitable destination for an industrial sludge that can cover the wastewater treatment costs of small waste generators. Optimized stabilization/solidification technology was used to treat hazardous waste from an electroplating industry that is currently released untreated to the environment. The stabilized/solidified (S/S) waste product was used as a raw material to build concrete blocks, to be sold as pavement blocks or used in roadbeds and/or parking lots. The quality of the blocks containing a mixture of cement, lime, clay and waste was evaluated by means of leaching and solubility tests according to the current Brazilian waste regulations. Results showed very low metal leachability and solubility of the block constituents, indicating a low environmental impact. Concerning economic benefits from the S/S process and reuse of the resultant product, the cost of untreated heavy metal-containing sludge disposal to landfill is usually on the order of US$ 150-200 per tonne of waste, while 1tonne of concrete roadbed blocks (with 25% of S/S waste constitution) has a value of around US$ 100. The results of this work showed that the cement, clay and lime-based process of stabilization/solidification of hazardous waste sludge is sufficiently effective and economically viable to stimulate the treatment of wastewater from small industrial waste generators.

Towards sustainable pollution management

NASA Astrophysics Data System (ADS)

Jern, N. G. W.

2017-03-01

It is often overlooked pollution control itself may not be entirely free from adverse impact on the environment if considered from a more holistic perspective. For example mechanised wastewater treatment is energy intensive and so has a carbon footprint because of the need to move air to supply oxygen to the aerobic treatment process. The aerobic treatment process then results in excess bio-sludge which requires disposal and if such is not appropriately performed, then there is risk of surface and groundwater contamination. This presentation explores the changes which have been investigated and are beginning to be implemented in wastewater, sludge, and agro-industrial wastes management which are more environmentally benign. Three examples shall be used to illustrate the discussion. The first example uses the conventional sewage treatment system with a unit process arrangement which converts carbonaceous pollutants from soluble and colloidal forms to particulate forms with an aerobic process before attempting energy recovery with an anaerobic process. Such an arrangement does, however, result in a negative energy balance. This is not withstanding the fact there is potentially more energy in sewage than is required to treat it if that energy can be effectively harvested. The latter can be achieved by removing the carbonaceous pollutants before the aerobic process and thereby using the aerobic process for polishing instead of treating. The carbonaceous pollutants so recovered then becomes the feed for the anaerobic process. Unfortunately conventional anaerobic sludge digestion only removes 35-45% of the organic material fed. Since biogas production (and hence energy recovery) is linked to the amount of organic material which can be degraded anaerobically, the effectiveness of the anaerobic digestion process needs to be improved. Contrary to a commonly held belief wherein methanogenesis is the “bottleneck” in anaerobic processes, hydrolysis is in sludge digestion. Hydrolysis can be enhanced thermally, chemically and biologically. With better anaerobic digestion, the digestate would have more N and P released. The digestate can be blended with organic fertilizers which have been augmented with microbes capable of producing phytohormones. The latter enable crop plants to use inorganic fertilizers more effectively and hence reducing the quantity of inorganic fertilizers required significantly. Use of such organic fertilizers rejuvenates soils which have been subjected to prolonged application of inorganic fertilisers since the latter can result in stagnating or even declining crop yields.

Septage unit treatment by sludge treatment reed beds for easy management and reuse: performance and design considerations.

PubMed

Kim, Boram; Bel, Thomas; Bourdoncle, Pascal; Dimare, Jocelyne; Troesch, Stéphane; Molle, Pascal

2018-01-01

Sustainable treatment and management of fecal sludge in rural areas require adapted solutions. Rustic and simple operating processes such as sludge treatment reed beds (STRB) have been increasingly considered for this purpose. The biggest full scale (2,600 m 2 of STRB) septage treatment unit in France had been built in Nègrepelisse with the final objectives of reusing treated sludge and leachates for agriculture spreading and tree irrigation, respectively. The aim of this investigation was to validate the treatment chain of this installation. The obtained field data showed firstly that the overall removal efficiencies of STRB were satisfactory and stable. Removal rates higher than 98% for chemical oxygen demand and suspended solids and a 95% for Kjeldahl nitrogen represented so far a beneficial septage treatment by STRB. The highlighted necessity of a suitable complementary leachate treatment (before tree irrigation) justified the presence of the second stage of vertical flow constructed wetland. The sludge deposit drying and mineralization efficiencies were on the right track. According to hydrotextural diagram analysis, surface deposit was however found to have high deformability probably due to the youth of the installation. An in-depth understanding of STRB system needs continuous long-term studies.

A case study of coupling upflow anaerobic sludge blanket (UASB) and ANITA™ Mox process to treat high-strength landfill leachate.

PubMed

Lu, Ting; George, Biju; Zhao, Hong; Liu, Wenjun

2016-01-01

A pilot study was conducted to study the treatability of high-strength landfill leachate by a combined process including upflow anaerobic sludge blanket (UASB), carbon removal (C-stage) moving bed biofilm reactor (MBBR) and ANITA™ Mox process. The major innovation on this pilot study is the patent-pending process invented by Veolia that integrates the above three unit processes with an effluent recycle stream, which not only maintains the low hydraulic retention time to enhance the treatment performance but also reduces inhibiting effect from chemicals present in the high-strength leachate. This pilot study has demonstrated that the combined process was capable of treating high-strength leachate with efficient chemical oxygen demand (COD) and nitrogen removals. The COD removal efficiency by the UASB was 93% (from 45,000 to 3,000 mg/L) at a loading rate of 10 kg/(m(3)·d). The C-stage MBBR removed an additional 500 to 1,000 mg/L of COD at a surface removal rate (SRR) of 5 g/(m(2)·d) and precipitated 400 mg/L of calcium. The total inorganic nitrogen removal efficiency by the ANITA Mox reactor was about 70% at SRR of 1.0 g/(m(2)·d).

Multistage treatment system for raw leachate from sanitary landfill combining biological nitrification-denitrification/solar photo-Fenton/biological processes, at a scale close to industrial--biodegradability enhancement and evolution profile of trace pollutants.

PubMed

Silva, Tânia F C V; Silva, M Elisabete F; Cunha-Queda, A Cristina; Fonseca, Amélia; Saraiva, Isabel; Sousa, M A; Gonçalves, C; Alpendurada, M F; Boaventura, Rui A R; Vilar, Vítor J P

2013-10-15

A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO. The raw leachate was characterized by a high concentration of humic substances (HS) (1211 mg CHS/L), representing 39% of the dissolved organic carbon (DOC) content, and a high nitrogen content, mainly in the form of ammonium nitrogen (>3.8 g NH4(+)-N/L). In the first biological oxidation step, a 95% removal of total nitrogen and a 39% mineralization in terms of DOC were achieved, remaining only the recalcitrant fraction, mainly attributed to HS (57% of DOC). Under aerobic conditions, the highest nitrification rate obtained was 8.2 mg NH4(+)-N/h/g of volatile suspended solids (VSS), and under anoxic conditions, the maximum denitrification rate obtained was 5.8 mg (NO2(-)-N + NO3(-)-N)/h/g VSS, with a C/N consumption ratio of 2.4 mg CH3OH/mg (NO2(-)-N + NO3(-)-N). The precipitation of humic acids (37% of HS) after acidification of the bio-treated leachate corresponds to a 96% DOC abatement. The amount of UV energy and H2O2 consumption during the photo-Fenton reaction was 30% higher in the experiment without sludge removal and, consequently, the reaction velocity was 30% lower. The phototreatment process led to the depletion of HS >80%, of low-molecular-weight carboxylate anions >70% and other organic micropollutants, thus resulting in a total biodegradability increase of >70%. The second biological oxidation allowed to obtain a final treated leachate in compliance with legal discharge limits regarding water bodies (with the exception of sulfate ions), considering the experiment without sludge. Finally, the high efficiency of the overall treatment process was further reinforced by the total removal percentages attained for the identified organic trace contaminants (>90%). Copyright © 2013 Elsevier Ltd. All rights reserved.

Post-anaerobic digestion thermal hydrolysis of sewage sludge and food waste: Effect on methane yields, dewaterability and solids reduction.

PubMed

Svensson, Kine; Kjørlaug, Oda; Higgins, Matthew J; Linjordet, Roar; Horn, Svein J

2018-04-01

Post-anaerobic digestion (PAD) treatment technologies have been suggested for anaerobic digestion (AD) to improve process efficiency and assure hygenization of organic waste. Because AD reduces the amount of organic waste, PAD can be applied to a much smaller volume of waste compared to pre-digestion treatment, thereby improving efficiency. In this study, dewatered digestate cakes from two different AD plants were thermally hydrolyzed and dewatered, and the liquid fraction was recirculated to a semi-continuous AD reactor. The thermal hydrolysis was more efficient in relation to methane yields and extent of dewaterability for the cake from a plant treating waste activated sludge, than the cake from a plant treating source separated food waste (SSFW). Temperatures above 165 °C yielded the best results. Post-treatment improved volumetric methane yields by 7% and the COD-reduction increased from 68% to 74% in a mesophilic (37 °C) semi-continuous system despite lowering the solid retention time (from 17 to 14 days) compared to a conventional system with pre-treatment of feed substrates at 70 °C. Results from thermogravimetric analysis showed an expected increase in maximum TS content of dewatered digestate cake from 34% up to 46% for the SSFW digestate cake, and from 17% up to 43% in the sludge digestate cake, after the PAD thermal hydrolysis process (PAD-THP). The increased dewatering alone accounts for a reduction in wet mass of cake leaving the plant of 60% in the case of sludge digestate cake. Additionaly, the increased VS-reduction will contribute to further reduce the mass of wet cake. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of activated sludge culture conditions on Waxberry wastewater

NASA Astrophysics Data System (ADS)

Shi, Liang; He, Lingfeng; Zhang, Yongli

2018-03-01

Treated activated sludge is suitable for the treatment of wastewater. Biochemical method is used to treat the wastewater, and the influence of time on the COD index is investigated. The results showed that time had a significant effect on COD, and then affected the performance of activated sludge. Under different time, according to the order of time from short to long, COD decreases in turn. Under the action of activated sludge, the degradation of myrica rubra wastewater samples, after 25 h aeration for 96 h, the effect is better. Under this condition, the COD value was reduced at 72 mg/L, and the COD removal efficiency of myrica rubra wastewater was up to 93.39 %, and reached the two level discharge standard of municipal wastewater treatment.

Treatment of nanowaste via fast crystal growth: with recycling of nano-SnO2 from electroplating sludge as a study case.

PubMed

Zhuang, Zanyong; Xu, Xinjiang; Wang, Yongjing; Wang, Yandi; Huang, Feng; Lin, Zhang

2012-04-15

The treatment of industrial sludge containing amorphous/nanophase metal oxides or hydroxides is one of the vital issues in hazardous waste disposal. In this work, we developed a strategy to recycle nano-SnO(2) from tinplate electroplating sludge. It revealed that the major components of this sludge were acid soluble Sn and Fe amorphous phases. By introducing NaOH as a mineralizer, a fast growth of amorphous Sn compound into acid-insoluble SnO(2) nanowires was achieved selectively. Thus, the as-formed nano-SnO(2) could be recycled via dissolving other solid compositions in the sludge by using acid. The role of NaOH on accelerating both the Oriented Attachment (OA) and Ostwald Ripening (OR) growth of SnO(2) was discussed, which was regarded as a critical factor for treating the sludge. A pilot-scale experiment was conducted to treat 2.3 kg original sludge and the recycling of about 90 g nano-SnO(2) was achieved. We anticipate this work can provide a good example for the recycling of valuable metals from industrial sludge containing fine metal oxides or hydroxides. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluation of advanced wastewater treatment systems for water reuse in the era of advanced wastewater treatment

NASA Astrophysics Data System (ADS)

Kon, Hisao; Watanabe, Masahiro

This study focuses on effluent COD concentration from wastewater treatment in regards to the reduction of pathogenic bacteria and trace substances in public waters. The main types of secondary wastewater treatment were conventional activated sludge processes. Recently, however, advance wastewater treatment processes have been developed aimed at the removal of nitrogen and phosphorus, and the effluent quality of these processes was analyzed in this study. Treatment processes for water reclamation that make effluent to meet the target water quality for reuse purposes were selected and also optimum design parameters for these processes were proposed. It was found that the treatment cost to water reclamation was greatly affected by the effluent COD of the secondary treatment. It is important to maintain low COD concentration in the secondary treated effluent. Therefore, it is considered that adequate cost benefits would be obtained by achieving target COD quality through shifting from a conventional activated sludge process to an advanced treatment process.

Anaerobic digestion potential of urban organic waste: a case study in Malmö.

PubMed

Davidsson, Asa; Jansen, Jes la Cour; Appelqvist, Björn; Gruvberger, Christopher; Hallmer, Martin

2007-04-01

A study of existing organic waste types in Malmö, Sweden was performed. The purpose was to gather information about organic waste types in the city to be able to estimate the potential for anaerobic treatment in existing digesters at the wastewater treatment plan (WWTP). The urban organic waste types that could have a significant potential for anaerobic digestion amount to about 50 000 tonnes year(-1) (sludge excluded). Some of the waste types were further evaluated by methane potential tests and continuous pilot-scale digestion. Single-substrate digestion and co-digestion of pre-treated, source-sorted organic fraction of municipal solid waste, wastewater sludge, sludge from grease traps and fruit and vegetable waste were carried out. The experiments showed that codigestion of grease sludge and WWTP sludge was a better way of making use of the methane potential in the grease trap sludge than single-substrate digestion. Another way of increasing the methane production in sludge digesters is to add source-sorted organic fraction of municipal solid waste (SSOFMSW). Adding SSOFMSW (20% of the total volatile solids) gave a 10-15% higher yield than could be expected by comparison with separate digestion of sludge respective SSOFMSW. Co-digestion of sludge and organic waste is beneficial not just for increasing gas production but also for stabilizing the digestion process. This was seen when co-digesting fruit and vegetable waste and sludge. When co-digested with sludge, this waste gave a better result than the separate digestion of fruit and vegetable waste. Considering single-substrate digestion, SSOFMSW is the only waste in the study which makes up a sufficient quantity to be suitable as the base substrate in a full-scale digester that is separated from the sludge digestion. The two types of SSOFMSW tested in the pilot-scale digestion were operated successfully at mesophilic temperature. By adding SSOFMSW, grease trap sludge and fruit and vegetables waste to sludge digesters at the wastewater treatment plant, the yearly energy production from methane could be expected to increase from 24 to 43 GWh.

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

NASA Astrophysics Data System (ADS)

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.

Critical evaluation of the use of the hydroxyapatite as a stabilizing agent to reduce the mobility of Zn and Ni in sewage sludge amended soils.

PubMed

Zupancic, Marija; Bukovec, Peter; Milacic, Radmila; Scancar, Janez

2006-01-01

The leachability of zinc (Zn) and nickel (Ni) was investigated in various soil types amended with sewage sludge and sewage sludge treated with hydroxyapatite. Sandy, clay and peat soils were investigated. For leachability tests, plastic columns (diameter 9 cm, height 50 cm) were filled with moist samples up to a height of 25 cm. Sewage sludge (1 kg) was mixed with 4.6 kg of clay and sandy soils and with 6.7 kg of peat soil. For sewage sludge mixtures treated with hydroxyapatite, 0.5 kg of the hydroxyapatite was added to 1 kg of the sewage sludge. Neutral (pH 7) and acid precipitation (pH 3.5) were applied. Acid precipitation was prepared from concentrated HNO(3), H(2)SO(4) and fresh doubly distilled water. The amount of precipitation corresponded to the average annual precipitation for the city of Ljubljana, Slovenia. It was divided into eight equal portions and applied sequentially on the top of the columns. The results indicated that the leachabilities of Zn in sewage sludge amended peat and clay soils were low (below 0.3% of total Zn content) and of Ni in sewage sludge amended sandy, clay and peat soil below 1.9% of total Ni content. In sewage sludge amended sandy soil, the leachability of Zn was higher (11% of Zn content). The pH of precipitation had no influence on the leachability of either metal. Treatment of sewage sludge with hydroxyapatite efficiently reduced the leachability of Zn in sewage sludge amended sandy soil (from 11% to 0.2% of total Zn content). In clay and peat sewage sludge amended soils, soil characteristics rather than hydroxyapatite treatment dominate Zn mobility.

Impact of fine mesh sieve primary treatment on nitrogen removal in moving bed biofilm reactors.

PubMed

Rusten, B; Razafimanantsoa, V A; Andriamiarinjaka, M A; Otis, C L; Sahu, A K; Bilstad, T

2016-01-01

The purpose of this project was to investigate the effect of selective particle removal during primary treatment on nitrogen removal in moving bed biofilm reactors (MBBRs). Two small MBBR pilot plants were operated in parallel, where one train treated 2 mm screened municipal wastewater and the other train treated wastewater that had passed through a Salsnes Filter SF1000 rotating belt sieve (RBS) with a 33 µs sieve cloth. The SF1000 was operated without a filter mat on the belt. The tests confirmed that, for the wastewater characteristics at the test plant, Salsnes Filter primary treatment with a 33 µs RBS and no filter mat produced a primary effluent that was close to optimum. Removal of organic matter with the 33 µs sieve had no negative effect on the denitrification process. Nitrification rates improved by 10-15% in the train with 33 µs RBS primary treatment. Mass balance calculations showed that without RBS primary treatment, the oxygen demand in the biological system was 36% higher. Other studies have shown that the sludge produced by RBS primary treatment is beneficial for biogas production and will also significantly improve sludge dewatering of the combined primary and biological sludge.

Effect of sewage sludge on formation of acidic ground water at a reclaimed coal mine

USGS Publications Warehouse

Cravotta, C.A.

1998-01-01

Data on rock, ground water, vadose water, and vadose gas chemistry were collected for two years after sewage sludge was applied at a reclaimed surface coal mine in Pennsylvania to determine if surface-applied sludge is an effective barrier to oxygen influx, contributes metals and nutrients to ground water, and promotes the acidification of ground water. Acidity, sulfate, and metals concentrations were elevated in the ground water (6- to 21-m depth) from spoil relative to unmined rock because of active oxidation of pyrite and dissolution of aluminosilicate, carbonate, and Mn-Fe-oxide minerals in the spoil. Concentrations of acidity, sulfate, metals (Fe, Mn, Al, Cd, Cu, Cr, Ni, Zn), and nitrate, and abundances of iron-oxidizing bacteria were elevated in the ground water from sludge-treated spoil relative to untreated spoil having a similar mineral composition; however, gaseous and dissolved oxygen concentrations did not differ between the treatments. Abundances of iron-oxidizing bacteria in the ground water samples were positively correlated with concentrations of ammonia, nitrate, acidity, metals, and sulfate. Concentrations of metals in vadose water samples (<5-m depth) from sludge-treated spoil (pH 5.9) were not elevated relative to untreated spoil (pH 4.4). In contrast, concentrations of nitrate were elevated in vadose water samples from sludge-treated spoil, frequently exceeding 10 mg/L. Downgradient decreases in nitrate to less than 3 mg/L and increases in sulfate concentrations in underlying ground water could result from oxidation of pyrite by nitrate. Thus, sewage sludge added to pyritic spoil can increase the growth of iron-oxidizing bacteria, the oxidation of pyrite, and the acidification of ground water. Nevertheless, the overall effects on ground water chemistry from the sludge were small and probably short-lived relative to the effects from mining only.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

RUTHERFORD WW; GEUTHER WJ; STRANKMAN MR

2009-04-29

The CH2M HILL Plateau Remediation Company (CHPRC) has recommended to the U.S. Department of Energy (DOE) a two phase approach for removal and storage (Phase 1) and treatment and packaging for offsite shipment (Phase 2) of the sludge currently stored within the 105-K West Basin. This two phased strategy enables early removal of sludge from the 105-K West Basin by 2015, allowing remediation of historical unplanned releases of waste and closure of the 100-K Area. In Phase 1, the sludge currently stored in the Engineered Containers and Settler Tanks within the 105-K West Basin will be transferred into sludge transportmore » and storage containers (STSCs). The STSCs will be transported to an interim storage facility. In Phase 2, sludge will be processed (treated) to meet shipping and disposal requirements and the sludge will be packaged for final disposal at a geologic repository. The purpose of this study is to evaluate two alternatives for interim Phase 1 storage of K Basin sludge. The cost, schedule, and risks for sludge storage at a newly-constructed Alternate Storage Facility (ASF) are compared to those at T Plant, which has been used previously for sludge storage. Based on the results of the assessment, T Plant is recommended for Phase 1 interim storage of sludge. Key elements that support this recommendation are the following: (1) T Plant has a proven process for storing sludge; (2) T Plant storage can be implemented at a lower incremental cost than the ASF; and (3) T Plant storage has a more favorable schedule profile, which provides more float, than the ASF. Underpinning the recommendation of T Plant for sludge storage is the assumption that T Plant has a durable, extended mission independent of the K Basin sludge interim storage mission. If this assumption cannot be validated and the operating costs of T Plant are borne by the Sludge Treatment Project, the conclusions and recommendations of this study would change. The following decision-making strategy, which is dependent on the confidence that DOE has in the long term mission for T Plant, is proposed: (1) If the confidence level in a durable, extended T Plant mission independent of sludge storage is high, then the Sludge Treatment Project (STP) would continue to implement the path forward previously described in the Alternatives Report (HNF-39744). Risks to the sludge project can be minimized through the establishment of an Interface Control Document (ICD) defining agreed upon responsibilities for both the STP and T Plant Operations regarding the transfer and storage of sludge and ensuring that the T Plant upgrade and operational schedule is well integrated with the sludge storage activities. (2) If the confidence level in a durable, extended T Plant mission independent of sludge storage is uncertain, then the ASF conceptual design should be pursued on a parallel path with preparation of T Plant for sludge storage until those uncertainties are resolved. (3) Finally, if the confidence level in a durable, extended T Plant mission independent of sludge storage is low, then the ASF design should be selected to provide independence from the T Plant mission risk.« less

A comparison of the physical, chemical, and biological properties of sludges from a complete-mix activated sludge reactor and a submerged membrane bioreactor.

PubMed

Merlo, Rion P; Trussell, R Shane; Hermanowicz, Slawomir W; Jenkins, David

2007-03-01

The properties of sludges from a pilot-scale submerged membrane bioreactor (SMBR) and two bench-scale complete-mix, activated sludge (CMAS) reactors treating municipal primary effluent were determined. Compared with the CMAS sludges, the SMBR sludge contained a higher amount of soluble microbial products (SMP) and colloidal material attributed to the use of a membrane for solid-liquid separation; a higher amount nocardioform bacteria, resulting from efficient foam trapping; and a lower amount of extracellular polymeric substances (EPS), possibly because there was no selective pressure for the sludge to settle. High aeration rates in both the CMAS and SMBR reactors produced sludges with higher numbers of smaller particles. Normalized capillary suction time values for the SMBR sludge were lower than for the CMAS sludges, possibly because of its lower EPS content.

Integrated fixed-biofilm activated sludge reactor as a powerful tool to enrich anammox biofilm and granular sludge.

PubMed

Zhang, Liang; Liu, Miaomiao; Zhang, Shujun; Yang, Yandong; Peng, Yongzhen

2015-12-01

A pilot-scale activated sludge bioreactor was filled with immobile carrier to treat high ammonium wastewater. Autotrophic nitrogen elimination occurred rapidly by inoculating nitrifying activated sludge and anammox biofilm. As the ammonium loading rate increased, nitrogen removal rate of 1.2kgNm(-3)d(-1) was obtained with the removal efficiency of 80%. Activated sludge diameter distribution profiles presented two peak values, indicating simultaneous existence of flocculent and granular sludge. Red granular sludge was observed in the reactor. Furthermore, the results of morphological and molecular analysis showed that the characteristics of granular sludge were similar to that of biofilm, while much different from the flocculent sludge. It was assumed granular sludge was formed through the continuous growth and detachment of anammox biofilm. The mechanism of granular sludge formation was discussed and the procedure model was proposed. According to the experimental results, the integrated fixed-biofilm activated sludge reactor provided an alternative to nitrogen removal based on anammox. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mathematical modelling of disintegration-limited co-digestion of OFMSW and sewage sludge.

PubMed

Esposito, G; Frunzo, L; Panico, A; d'Antonio, G

2008-01-01

This paper presents a mathematical model able to simulate under dynamic conditions the physical, chemical and biological processes prevailing in a OFMSW and sewage sludge anaerobic digestion system. The model proposed is based on differential mass balance equations for substrates, products and bacterial groups involved in the co-digestion process and includes the biochemical reactions of the substrate conversion and the kinetics of microbial growth and decay. The main peculiarity of the model is the surface based kinetic description of the OFMSW disintegration process, whereas the pH determination is based on a nine-order polynomial equation derived by acid-base equilibria. The model can be applied to simulate the co-digestion process for several purposes, such as the evaluation of the optimal process conditions in terms of OFMSW/sewage sludge ratio, temperature, OFMSW particle size, solid mixture retention time, reactor stirring rate, etc. Biogas production and composition can also be evaluated to estimate the potential energy production under different process conditions. In particular, model simulations reported in this paper show the model capability to predict the OFMSW amount which can be treated in the digester of an existing MWWTP and to assess the OFMSW particle size diminution pre-treatment required to increase the rate of the disintegration process, which otherwise can highly limit the co-digestion system. Copyright IWA Publishing 2008.

Enhanced reduction of excess sludge and nutrient removal in a pilot-scale A2O-MBR-TAD system.

PubMed

Ventura, J S; Seo, S; Chung, I; Yeom, I; Kim, H; Oh, Y; Jahng, D

2011-01-01

In this study, a pilot scale anaerobic-anoxic-oxic (A2O) process with submerged membrane (MBR) in the oxic tank was coupled with thermophilic aerobic digestion (TAD) reactor and was operated for longer than 600 days to treat real domestic wastewater. Regardless of the varying conditions of the system, the A2O-MBR-TAD process removed MLSS, TCOD, BOD, TN, TP, and E. coli about 99%, 96%, 96%, 70%, 83%, and 99%, respectively. The additional TP removal of the system was due to the precipitating agent directly added in the oxic reactor, without which TP removal was about 56%. In the TAD reactor, receiving MLSS from the oxic tank (MBR), about 25% of TSS and VSS were solubilized during 2 days of retention. The effluent of the TAD reactor was recycled into the anoxic tank of A2O-MBR to provide organic carbon for denitrification and cryptic growth. By controlling the flowrate of wasting stream from the MBR, sludge production decreased to almost zero. From these results, it was concluded that the A2O-MBR-TAD process could be a reliable option for excellent effluent quality and near zero-sludge production.

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

PubMed

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

2017-08-02

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

CASE STUDY: IN-SITU SOLIDIFICATION/STABILIZATION OF HAZARDOUS ACID WASTE OIL SLUDGE AND LESSONS LEARNED

EPA Science Inventory

The South 8th Street site contained a 2.5 acre oily sludge pit with very low pH waste produced by oil recycling activities. This sludge was treated using in-situ solidification/stabilization technology applied by deep soil mixing augers. The problems encountered, solutions develo...

Municipal sludge composting facility emissions -- comparison of wet scrubber and biofiltration control performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holzman, M.I.; Gammie, L.A.; Gilbert, P.E.

1997-12-31

The Metropolitan District (MDC) Water Pollution Control Plant located in Hartford, Connecticut operates a state-of-the-art composting facility to process municipal sewage sludge. An air emissions test program was performed to determine emission rates of criteria and non-criteria pollutants and to evaluate the performance of two types of emissions/odor control systems (biofiltration and wet scrubbing). The purpose of this report is to further the limited available emissions and control performance data on a municipal sewage sludge composting facility operation. The MDC`s sludge composting facility consists of a Biocell train and a Cure Cell train, each of which can currently receive approximatelymore » 20 wet tons per hour of sludge at 60% of full capacity. The minimum retention time in each train is 10.5 days. Air emissions from the Biocell train are treated by both a biofiltration system and a three-stage wet scrubber system. The biofilter and wet scrubber system operate in parallel, so as to allow direct comparison of performance. Emissions from the Cure Cell train are treated by a single biofiltration system. The wet scrubber system consists of a first stage reducing absorber (ammonia solution), followed by a second stage oxidation absorber (sodium hypochlorite and sulfuric acid), and a final residual scrubber (sodium hydroxide solution). The two biofiltration systems are identically sized at 10,000 square feet surface area and three feet depth. The emissions testing program was designed to obtain simultaneous inlet and outlet data across each control device. The measured pollutants included organo-sulfides, alcohols, aldehydes, ketones, pinenes, terpenes, total reduced sulfur compounds, chlorinated hydrocarbons, sulfuric acid, sodium hydroxide, ammonia, carbon monoxide and volatile organic compounds.« less

Effect of pH on phosphine production and the fate of phosphorus during anaerobic process with granular sludge.

PubMed

Ding, Lili; Wang, Xiaorong; Zhu, Yixin; Edwards, Marc; Glindemann, Dietmar; Ren, Hongqiang

2005-03-01

The effect of pH on phosphine formation during anaerobic cultivation of granular sludge was investigated. The sludge was taken from full-scale anaerobic reactors treating brewery wastewater. Acetate and phosphate were used as the carbon source and phosphorus source respectively. After 10 days cultivation in the dark, results showed that acidic conditions were more favorable for free phosphine production. At pH 5, the optimum concentration 86.42 ng PH3 m-3 of free phosphine was obtained. The level at pH 7 was reduced to 18.53 ng PH3 m-3, about 1/5 of the maximum. The maximum concentration of matrix-bound phosphine of 3.30 ng PH3 kg-1 wet sludge was achieved at pH 6. More than 83% of the total phosphine was matrix-bound phosphine, which accounted for 0.003-0.009 per thousand of the phosphate removal, while free phosphine comprised 0.00002-0.001 per thousand of the phosphate removal. Most of the phosphorus removal from solution was turned into chemical precipitation or was adsorbed by sludge. The mechanism of the phosphate reduction-step in the formation of phosphine production is still unknown. The promotion of phosphine formation by low pH is compatible with an acidic bio-corrosion mechanism of metal particles in the sludge or of metal phosphides which form phosphine at low pH.

Low-temperature thermal pre-treatment of municipal wastewater sludge: Process optimization and effects on solubilization and anaerobic degradation.

PubMed

Nazari, Laleh; Yuan, Zhongshun; Santoro, Domenico; Sarathy, Siva; Ho, Dang; Batstone, Damien; Xu, Chunbao Charles; Ray, Madhumita B

2017-04-15

The present study examines the relationship between the degree of solubilization and biodegradability of wastewater sludge in anaerobic digestion as a result of low-temperature thermal pre-treatment. The main effect of thermal pre-treatment is the disintegration of cell membranes and thus solubilization of organic compounds. There is an established correlation between chemical oxygen demand (COD) solubilization and temperature of thermal pre-treatment, but results of thermal pre-treatment in terms of biodegradability are not well understood. Aiming to determine the impact of low temperature treatments on biogas production, the thermal pre-treatment process was first optimized based on an experimental design study on waste activated sludge in batch mode. The optimum temperature, reaction time and pH of the process were determined to be 80 °C, 5 h and pH 10, respectively. All three factors had a strong individual effect (p < 0.001), with a significant interaction effect for temp. pH 2 (p = 0.002). Thermal pre-treatments, carried out on seven different municipal wastewater sludges at the above optimum operating conditions, produced increased COD solubilization of 18.3 ± 7.5% and VSS reduction of 27.7 ± 12.3% compared to the untreated sludges. The solubilization of proteins was significantly higher than carbohydrates. Methane produced in biochemical methane potential (BMP) tests, indicated initial higher rates (p = 0.0013) for the thermally treated samples (k hyd up to 5 times higher), although the ultimate methane yields were not significantly affected by the treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

The mechanisms of granulation of activated sludge in wastewater treatment, its optimization, and impact on effluent quality.

PubMed

Wilén, Britt-Marie; Liébana, Raquel; Persson, Frank; Modin, Oskar; Hermansson, Malte

2018-06-01

Granular activated sludge has gained increasing interest due to its potential in treating wastewater in a compact and efficient way. It is well-established that activated sludge can form granules under certain environmental conditions such as batch-wise operation with feast-famine feeding, high hydrodynamic shear forces, and short settling time which select for dense microbial aggregates. Aerobic granules with stable structure and functionality have been obtained with a range of different wastewaters seeded with different sources of sludge at different operational conditions, but the microbial communities developed differed substantially. In spite of this, granule instability occurs. In this review, the available literature on the mechanisms involved in granulation and how it affects the effluent quality is assessed with special attention given to the microbial interactions involved. To be able to optimize the process further, more knowledge is needed regarding the influence of microbial communities and their metabolism on granule stability and functionality. Studies performed at conditions similar to full-scale such as fluctuation in organic loading rate, hydrodynamic conditions, temperature, incoming particles, and feed water microorganisms need further investigations.

Analysis of pharmaceutical biodegradation of WWTP sludge using composting and identification of certain microorganisms involved in the process.

PubMed

Iranzo, María; Gamón, Miguel; Boluda, Rafael; Mormeneo, Salvador

2018-06-04

Pharmaceuticals (PhCs) are organic contaminants that have been detected in wastewater, surface water, and soils throughout the world. The presence of 10 commonly used PhCs in Spain (azithromycin, benzylpenicillin, citalopram, fluconazole, fluoxetine, ibuprofen, irbesartan, olanzapine, telmisartan, and venlafaxine) was analysed at four wastewater treatment plants, and the changes in their concentrations during treatment were assessed. Although certain some PhCs were degraded in the treated water, their presence in sewage sludge increased in all cases. The sewage sludge was composted using rice straw to degrade the PhCs, and the composting efficiency was modified by changes in the relative C/N ratio of the composting blend. Using a simple microbiological culture process for enrichment, 11 different strains of microorganisms that degraded specific PhCs were identified. Ibuprofen and azithromycin were metabolized by one and four strains, respectively, and both PhCs were used as a carbon source; in addition, six strains used irbesartan as a nitrogen source. Copyright © 2018 Elsevier B.V. All rights reserved.

Forest Thrives In Sludge Application Tests

Treesearch

Dale G. Brockway

1988-01-01

A six-year, state and federal research-demonstration project to recycle treated municipal wastewater sludge on forest lands has resulted in dramatic growth increase of trees, groundcover and wildlife populations.

Effects of dissolved oxygen on performance and microbial community structure in a micro-aerobic hydrolysis sludge in situ reduction process.

PubMed

Niu, Tianhao; Zhou, Zhen; Shen, Xuelian; Qiao, Weimin; Jiang, Lu-Man; Pan, Wei; Zhou, Jijun

2016-03-01

A sludge process reduction activated sludge (SPRAS), with a sludge process reduction module composed of a micro-aerobic tank and a settler positioned before conventional activated sludge process, showed good performance of pollutant removal and sludge reduction. Two SPRAS systems were operated to investigate effects of micro-aeration on sludge reduction performance and microbial community structure. When dissolved oxygen (DO) concentration in the micro-aerobic tank decreased from 2.5 (SPH) to 0.5 (SPL) mg/L, the sludge reduction efficiency increased from 42.9% to 68.3%. Compared to SPH, activated sludge in SPL showed higher contents of extracellular polymeric substances and dissolved organic matter. Destabilization of floc structure in the settler, and cell lysis in the sludge process reduction module were two major reasons for sludge reduction. Illumina-MiSeq sequencing showed that microbial diversity decreased under high DO concentration. Proteobacteria, Bacteroidetes and Chloroflexi were the most abundant phyla in the SPRAS. Specific comparisons down to the class and genus level showed that fermentative, predatory and slow-growing bacteria in SPL community were more abundant than in SPH. The results revealed that micro-aeration in the SPRAS improved hydrolysis efficiency and enriched fermentative and predatory bacteria responsible for sludge reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Integrated copper-containing wastewater treatment using xanthate process.

PubMed

Chang, Yi-Kuo; Chang, Juu-En; Lin, Tzong-Tzeng; Hsu, Yu-Ming

2002-09-02

Although, the xanthate process has been shown to be an effective method for heavy metal removal from contaminated water, a heavy metal contaminated residual sludge is produced by the treatment process and the metal-xanthate sludge must be handled in accordance with the Taiwan EPA's waste disposal requirements. This work employed potassium ethyl xanthate (KEX) to remove copper ions from wastewater. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) were used to determine the leaching potential and stability characteristics of the residual copper xanthate (Cu-EX) complexes. Results from metal removal experiments showed that KEX was suitable for the treatment of copper-containing wastewater over a wide copper concentration range (50, 100, 500, and 1000 mg/l) to the level that meets the Taiwan EPA's effluent regulations (3mg/l). The TCLP results of the residual Cu-EX complexes could meet the current regulations and thus the Cu-EX complexes could be treated as a non-hazardous material. Besides, the results of SDLT indicated that the complexes exhibited an excellent performance for stabilizing metals under acidic conditions, even slight chemical changes of the complexes occurred during extraction. The xanthate process, mixing KEX with copper-bearing solution to form Cu-EX precipitates, offered a comprehensive strategy for solving both copper-containing wastewater problems and subsequent sludge disposal requirements.

Remediation of Mercury-Contaminated Storm Sewer Sediments from the West End Mercury Area at the Y-12 National Security Complex in Oak Ridge, Tennessee - 12061

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tremaine, Diana; Douglas, Steven G.

2012-07-01

The Y-12 National Security Complex in Oak Ridge, TN has faced an ongoing challenge from mercury entrapped in soils beneath and adjacent to buildings, storm sewers, and process pipelines. Previous actions to reduce the quantity and/or mobilization of mercury-contaminated media have included plugging of building floor drains, cleaning of sediment and sludge from sumps, manholes, drain lines, and storm sewers, lining/relining of storm sewers and replacement of a portion of the storm sewer trunk line, re-routing and removal of process piping, and installation of the Central Mercury Treatment System to capture and treat contaminated sump water. Despite the success ofmore » these actions, mercury flux in the storm sewer out-falls that discharge to Upper East Fork Poplar Creek (UEFPC) continues to pose a threat to long-term water quality. A video camera survey of the storm sewer network revealed several sections of storm sewer that had large cracks, separations, swells, and accumulations of sediment/sludge and debris. The selected remedy was to clean and line the sections of storm sewer pipe that were determined to be primary contributors to the mercury flux in the storm sewer out-falls. The project, referred to as the West End Mercury Area (WEMA) Storm Sewer Remediation Project, included cleaning sediment and debris from over 2,460 meters of storm sewer pipe followed by the installation of nearly 366 meters of cure-in-place pipe (CIPP) liner. One of the greatest challenges to the success of this project was the high cost of disposal associated with the mercury-contaminated sludge and wastewater generated from the storm sewer cleaning process. A contractor designed and operated an on-site wastewater pre-treatment system that successfully reduced mercury levels in 191 cubic meters of sludge to levels that allowed it to be disposed at Nevada Nuclear Security Site (NNSS) disposal cell as a non-hazardous, low-level waste. The system was also effective at pre-treating over 1,514,000 liters of wastewater to levels that met the waste acceptance criteria for the on-site West End [wastewater] Treatment Facility (WETF). This paper describes the storm sewer cleaning and lining process and the methods used to process the mercury-contaminated sludge and wastewater, as well as several 'lessons learned' that would be relevant to any future projects involving storm sewer cleaning and debris remediation. (authors)« less

Key process parameters involved in the treatment of olive mill wastewater by membrane bioreactor.

PubMed

Jaouad, Y; Villain-Gambier, M; Mandi, L; Marrot, B; Ouazzani, N

2018-04-18

The Olive Mill Wastewater (OMWW) biodegradation in an external ceramic membrane bioreactor (MBR) was investigated with a starting acclimation step with a Ultrafiltration (UF) membrane (150 kDa) and no sludge discharge in order to develop a specific biomass adapted to OMWW biodegradation. After acclimation step, UF was replaced by an Microfiltration (MF) membrane (0.1 µm). Sludge Retention Time (SRT) was set around 25 days and Food to Microorganisms ratio (F/M) was fixed at 0.2 kg COD  kg MLVSS -1  d -1 . At stable state, removal of the main phenolic compounds (hydroxytyrosol and tyrosol) and Chemical Oxygen Demand (COD) were successfully reached (95% both). Considered as a predominant fouling factor, but never quantified in MBR treated OMWW, Soluble Microbial Products (SMP) proteins, polysaccharides and humic substances concentrations were determined (80, 110 and 360 mg L -1 respectively). At the same time, fouling was easily managed due to favourable hydraulic conditions of external ceramic MBR. Therefore, OMWW could be efficiently and durably treated by an MF MBR process under adapted operating parameters.

Microbial quantification in activated sludge: the hits and misses.

PubMed

Hall, S J; Keller, J; Blackall, L L

2003-01-01

Since the implementation of the activated sludge process for treating wastewater, there has been a reliance on chemical and physical parameters to monitor the system. However, in biological nutrient removal (BNR) processes, the microorganisms responsible for some of the transformations should be used to monitor the processes with the overall goal to achieve better treatment performance. The development of in situ identification and rapid quantification techniques for key microorganisms involved in BNR are required to achieve this goal. This study explored the quantification of Nitrospira, a key organism in the oxidation of nitrite to nitrate in BNR. Two molecular genetic microbial quantification techniques were evaluated: real-time polymerase chain reaction (PCR) and fluorescence in situ hybridisation (FISH) followed by digital image analysis. A correlation between the Nitrospira quantitative data and the nitrate production rate, determined in batch tests, was attempted. The disadvantages and advantages of both methods will be discussed.

Comparative evaluation of ceftriaxone- and cefotaxime-induced biliary pseudolithiasis or nephrolithiasis: A prospective study in 154 children.

PubMed

Ustyol, L; Bulut, M D; Agengin, K; Bala, K A; Yavuz, A; Bora, A; Demiroren, K; Dogan, M

2017-06-01

Biliary lithiasis, or sludge, and nephrolithiasis have been reported as a possible complication of ceftriaxone therapy. However, no study related to cefotaxime-induced biliary pseudolithiasis or nephrolithiasis was observed in the literature. Therefore, we investigated the comparative formation of biliary pseudolithiasis and nephrolithiasis after cefotaxime and ceftriaxone therapies. The patients treated with ceftriaxone or cefotaxime were enrolled during the study period. Ultrasound imaging of the biliary and urinary tract was performed in all patients before and after the treatment. The patients with a positive sonographic finding at the end of treatment were followed up with monthly ultrasonography for 3 months. The present study showed that abnormal biliary sonographic findings were demonstrated in 18 children (20.9%) treated with ceftriaxone, 13 (15.1%) had biliary lithiasis, 5 (5.8%) had biliary sludge and 1 (1.2%) had nephrolithiasis. Abnormal biliary sonographic findings were demonstrated in only four (5.9%) children treated with cefotaxime who had biliary sludge and only one (1.5%) had nephrolithiasis. It was observed that older age was at significantly higher risk of developing biliary sludge or stone formation. Receiver operating characteristic analysis was performed to determine the residual risk and analysis found that 4.5 years was the cut-off value for age. The present study is unique in the literature for reporting for the first time gall bladder sludge and nephrolithiasis associated with cefotaxime use. Therefore, patients treated with cefotaxime should be monitored for serious complications like patients treated with ceftriaxone. Nevertheless, if third-generation cephalosporin is used, cefotaxime is recommended to be used rather than ceftriaxone.

Bacterial community dynamics in long-term operation of a pilot plant using aerobic granular sludge to treat pig slurry.

PubMed

Fra-Vázquez, A; Morales, N; Figueroa, M; Val Del Río, A; Regueiro, L; Campos, J L; Mosquera-Corral, A

2016-09-01

Aerobic granular sludge represents an interesting approach for simultaneous organic matter and nitrogen removal in wastewater treatment plants. However, the information about microbial communities in aerobic granular systems dealing with industrial wastewater like pig slurry is limited. Herein, bacterial diversity and dynamics were assessed in a pilot scale plant using aerobic granular sludge for organic matter and nitrogen elimination from swine slurry during more than 300 days. Results indicated that bacterial composition evolved throughout the operational period from flocculent activated sludge, used as inoculum, to mature aerobic granules. Bacterial diversity increased at the beginning of the granulation process and then declined due to the application of transient organic matter and nitrogen loads. The operational conditions of the pilot plant and the degree of granulation determined the microbial community of the aerobic granules. Brachymonas, Zoogloea and Thauera were attributed with structural function as they are able to produce extracellular polymeric substances to maintain the granular structure. Nitrogen removal was justified by partial nitrification (Nitrosomonas) and denitrification (Thauera and Zoogloea), while Comamonas was identified as the main organic matter oxidizing bacteria. Overall, clear links between bacterial dynamics and composition with process performance were found and will help to predict their biological functions in wastewater ecosystems improving the future control of the process. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1212-1221, 2016. © 2016 American Institute of Chemical Engineers.

An ASM/ADM model interface for dynamic plant-wide simulation.

PubMed

Nopens, Ingmar; Batstone, Damien J; Copp, John B; Jeppsson, Ulf; Volcke, Eveline; Alex, Jens; Vanrolleghem, Peter A

2009-04-01

Mathematical modelling has proven to be very useful in process design, operation and optimisation. A recent trend in WWTP modelling is to include the different subunits in so-called plant-wide models rather than focusing on parts of the entire process. One example of a typical plant-wide model is the coupling of an upstream activated sludge plant (including primary settler, and secondary clarifier) to an anaerobic digester for sludge digestion. One of the key challenges when coupling these processes has been the definition of an interface between the well accepted activated sludge model (ASM1) and anaerobic digestion model (ADM1). Current characterisation and interface models have key limitations, the most critical of which is the over-use of X(c) (or lumped complex) variable as a main input to the ADM1. Over-use of X(c) does not allow for variation of degradability, carbon oxidation state or nitrogen content. In addition, achieving a target influent pH through the proper definition of the ionic system can be difficult. In this paper, we define an interface and characterisation model that maps degradable components directly to carbohydrates, proteins and lipids (and their soluble analogues), as well as organic acids, rather than using X(c). While this interface has been designed for use with the Benchmark Simulation Model No. 2 (BSM2), it is widely applicable to ADM1 input characterisation in general. We have demonstrated the model both hypothetically (BSM2), and practically on a full-scale anaerobic digester treating sewage sludge.

Long-term operation of a novel pilot-scale six tanks alternately operating activated sludge process in treating domestic wastewater.

PubMed

Mohammed, R N; Abu-Alhail, S; Xi-Wu, L

2014-08-01

The performance of a new pilot-scale six tanks activated sludge process has been evaluated for 303 d, receiving real domestic wastewater with a flow rate of 15-24.4 L/h. Partial nitrification via nitrite and microbial community structure were investigated in this system. The result shows that the nitrite accumulation rate was achieved successfully over 94% in the last aerobic compartment through a combination of short hydraulic retention time and low dissolved oxygen (DO) level. Fluorescence in situ hybridization analysis was used to correlate ammonia-oxidizing bacteria (AOB) numbers with nutrient removal via nitrite. It was shown that in response to complete and partial nitrification modes, the numbers of AOB population were 7.7 x 10(7) cells/g mixed liquor suspended solids (MLSS) and 5.31 x 10(8) cells/g MLSS, respectively. The morphology of the sludge indicated that there is a small rod-shaped and spherical cluster which was mainly dominantly bacterial according to scanning electron microscope. Higher pollutant removal efficiencies of 86.2%, 98%, and 96.1%, for total nitrogen, NH4+ - N, and total phosphorus, respectively, were achieved by a long-term operation of the six tanks activated sludge process at a low DO concentration and low chemical oxygen demand to nitrogen ratio which were approximately equal to the complete nitrification-ldenitrification with the addition of an external carbon source at a concentration of 1.5-2.5 mg/L.

Potential of biohydrogen production from effluents of citrus processing industry using anaerobic bacteria from sewage sludge.

PubMed

Torquato, Lilian D M; Pachiega, Renan; Crespi, Marisa S; Nespeca, Maurílio Gustavo; de Oliveira, José Eduardo; Maintinguer, Sandra I

2017-01-01

Citrus crops are among the most abundant crops in the world, which processing is mainly based on juice extraction, generating large amounts of effluents with properties that turn them into potential pollution sources if they are improperly discarded. This study evaluated the potential for bioconversion of effluents from citrus-processing industry (wastewater and vinasse) into hydrogen through the dark fermentation process, by applying anaerobic sewage sludge as inoculum. The inoculum was previously heat treated to eliminate H 2 -consumers microorganisms and improve its activity. Anaerobic batch reactors were operated in triplicate with increasing proportions (50, 80 and 100%) of each effluent as substrate at 37°C, pH 5.5. Citrus effluents had different effects on inoculum growth and H 2 yields, demonstrated by profiles of acetic acid, butyric acid, propionic acid and ethanol, the main by-products generated. It was verified that there was an increase in the production of biogas with the additions of either wastewater (7.3, 33.4 and 85.3mmolL -1 ) or vinasse (8.8, 12.7 and 13.4mmolL -1 ) in substrate. These effluents demonstrated remarkable energetic reuse perspectives: 24.0MJm -3 and 4.0MJm -3 , respectively. Besides promoting the integrated management and mitigation of anaerobic sludge and effluents from citrus industry, the biohydrogen production may be an alternative for the local energy supply, reducing the operational costs in their own facilities, while enabling a better utilization of the biological potential contained in sewage sludges. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phosphorus in waters from sewage sludge amended lysimeters.

PubMed

Hinesly, T D; Jones, R L

1990-01-01

In surface waters, phosphorus (P) concentrations exceeding 0.05 mg liter(-1) may cause eutrophic conditions. This study was undertaken to measure total P concentrations in runoff and tile drainage waters from land receiving either inorganic fertilizer or anaerobically digested sewage sludge. Total P was measured in runoff and tile drainage waters during 2 years of sample collections from instrumented, large-scale lysimeters planted to corn (Zea mays L.). During the 3 years prior to monitoring P concentrations, six of the lysimeter plots had been amended with anaerobically digested sewage sludge which supplied 5033 kg P per ha. Additional sludge applications supplied 1058 and 1989 kg P per ha during the first and second years of monitoring operations, respectively. Another six lysimeters were annually treated with fertilizer which included P applications amounting to 112 kg ha(-1). For years 1 and 2, respectively, annual losses from lysimeters treated with sewage sludge were 4.27 and 0.35 kg P per ha in runoff and 0.91 from 0.91 and 0.51 kg Per P per ha in drainage waters. Parallel annual losses of P from lysimeters treated with superphosphate were 2.15 and 0.17 kg ha(-1) in runoff and 0.53 and 0.35 kg ha(-1) in tile drainage waters. Sludge applications did not significantly change absolute soil contents of organic P, but did decrease the per cent of total P present in organic forms. Sludge and soil, respectively, contained 21 and 36% of their total P contents in organic forms. In sludge and soil about 85 and 64% of their respective total inorganic P contents were associated with the Al and Fe fractions. Sludge applications significantly increased soil contents of P in the saloid (water-soluble plus P extracted with 1 N NH(4)Cl), Al, Fe and reductant soluble P fractions, but contents of Ca-bound P were not changed. Total P contents of the soil below a depth of 30 cm were not affected by sludge incorporated to a depth of about 15 cm by plowing.

Inhibition kinetics and granular sludge in an ANAMMOX reactor treating mature landfill leachate.

PubMed

Yun, Li; Zhaoming, Zheng; Jun, Li; Baihang, Zhao; Wei, Bian; Yanzhuo, Zhang; Xiujie, Wang

2016-12-01

The present study reports the inhibition kinetics and granular sludge in an anaerobic ammonium oxidation (ANAMMOX) - up-flow anaerobic sludge blanket reactor fed with diluted mature landfill leachate. The activity of ANAMMOX bacteria was inhibited by addition of mature landfill leachate, but gradually adapted to the leachate. The system achieved efficient nitrogen removal during 65-75 d and the average removal efficiencies for NH 4 + -N, NO 2 - -N and total nitrogen (TN) were 96%, 95% and 87%, respectively. ANAMMOX was the main pathway of nitrogen removal in the system, and heterotrophic denitrification occurred simultaneously. In addition, aerobic ammonia oxidation and aerobic nitrite oxidation were active in this system. Inhibition kinetic experiments showed that the NH 4 + -N and NO 2 - -N inhibition concentration threshold of ANAMMOX were 489.03 mg/L and 192.36 mg/L, respectively. ANAMMOX was significantly inhibited by mature landfill leachate, and was completely inhibited when the leachate concentration was 1,450.69 mg/L (calculated in chemical oxygen demand). Thus, the inhibition concentration of substrate and landfill leachate should be considered when applying the ANAMMOX process to landfill leachate. The color of granular sludge ANAMMOX changed from brick-red into a reddish-brown. The particle size increased from small to large, with evident granulation of the ANAMMOX sludge.

Bacteriophages of wastewater foaming-associated filamentous Gordonia reduce host levels in raw activated sludge.

PubMed

Liu, Mei; Gill, Jason J; Young, Ry; Summer, Elizabeth J

2015-09-09

Filamentous bacteria are a normal and necessary component of the activated sludge wastewater treatment process, but the overgrowth of filamentous bacteria results in foaming and bulking associated disruptions. Bacteriophages, or phages, were investigated for their potential to reduce the titer of foaming bacteria in a mixed-microbial activated sludge matrix. Foaming-associated filamentous bacteria were isolated from activated sludge of a commercial wastewater treatment plan and identified as Gordonia species by 16S rDNA sequencing. Four representative phages were isolated that target G. malaquae and two un-named Gordonia species isolates. Electron microscopy revealed the phages to be siphophages with long tails. Three of the phages--GordTnk2, Gmala1, and GordDuk1--had very similar ~76 kb genomes, with >93% DNA identity. These genomes shared limited synteny with Rhodococcus equi phage ReqiDocB7 and Gordonia phage GTE7. In contrast, the genome of phage Gsput1 was smaller (43 kb) and was not similar enough to any known phage to be placed within an established phage type. Application of these four phages at MOIs of 5-15 significantly reduced Gordonia host levels in a wastewater sludge model by approximately 10-fold as compared to non-phage treated reactors. Phage control was observed for nine days after treatment.

Effects of sludge concentrations and different sponge configurations on the performance of a sponge-submerged membrane bioreactor.

PubMed

Nguyen, Tien Thanh; Ngo, Huu Hao; Guo, Wenshan; Li, Jianxin; Listowski, Andrzej

2012-07-01

The performance of a novel sponge-submerged membrane bioreactor (SSMBR) was evaluated to treat primary treated sewage effluent at three different activated sludge concentrations. Polyurethane sponge cubes with size of 1 × 1 × 1 cm were used as attached growth media in the bioreactor. The results indicated the successful removal of organic carbon and phosphorous with the efficiency higher than 98% at all conditions. Acclimatised sponge MBR showed about 5% better ammonia nitrogen removal at 5 and 10 g/L sludge concentration as compared to the new sponge system. The respiration test revealed that the specific oxygen uptake rate was around 1.0-3.5 mgO(2)/gVSS.h and likely more stable at 10 g/L sludge concentration. The sludge volume index of less than 100 mL/g during the operation indicated the good settling property of the sludge. The low mixed liquor suspended solid increase indicated that SSMBR could control the sludge production. This SSMBR was also successful in reducing membrane fouling with significant lower transmembrane pressure (e.g. only 0.5 kPa/day) compared to the conventional MBR system. Further study will be conducted to optimise other operating conditions.

Acidogenic fermentation of iron-enhanced primary sedimentation sludge under different pH conditions for production of volatile fatty acids.

PubMed

Lin, Lin; Li, Xiao-Yan

2018-03-01

Iron-based chemically enhanced primary sedimentation (CEPS) is increasingly adopted for wastewater treatment in mega cities, producing a large amount of sludge (Fe-sludge) with a high content of organics for potential organic resource recovery. In this experimental study, acidogenic fermentation was applied treat FeCl 3 -based CEPS sludge for production of volatile fatty acids (VFAs) at different pHs. Batch fermentation tests on the Fe-sludge with an organic content of 10 g-COD/L showed that the maximum VFAs production reached 2782.2 mg-COD/L in the reactor without pH control, and it reached 688.4, 3095.3, and 2603.7 mg-COD/L in reactors with pHs kept at 5.0, 6.0 and 8.0, respectively. Analysis of the acidogenesis kinetics and enzymatic activity indicated that the alkaline pH could accelerate the rate of organic hydrolysis but inhibited the further organic conversion to VFAs. In semi-continuous sludge fermentation tests, the VFAs yield in the pH6 reactor was 20% higher than that in the control reactor without pH regulation, while the VFAs yield in the pH8 reactor was 10% lower than the control. Illumina MiSeq sequencing revealed that key functional microorganisms known for effective sludge fermentation, including Bacteroidia and Erysipelotrichi, were enriched in the pH6 reactor with an enhanced VFAs production, while Clostridia became more abundant in the pH8 reactor to stand the unfavorable pH condition. The research presented acidogenic fermentation as an effective process for CEPS sludge treatment and organic resource recovery and provided the first insight into the related microbial community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Adaptive response of trivial activated sludge towards toxic effect of oNP, PCP and combination oNP/PCP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Topalova, Y.; Dimkov, R.; Kozuharov, D.

1999-01-01

The reaction of the real aerobic activated sludge taken from the Sofia Waste Water Treatment Plant (SWWTP) and treated with the xenobiotics pentachlorphenol (PCP) (0.16 mMol), ortho-nitrophenol (oNP) (0.58 mMol) and with a combination of PCP (0.08 mMol), oNP (0.29 mMol) has been investigated in a model detoxification process. The adaptive changes are studied in the microbial structure level and at the level of changes in the qualitative and quantitative parameters of the macro-organisms in the activated sludge (consuments of 1 and 2 level). The presence of several different taxonomic groups has been shown by other researchers to be essentialmore » in the detoxification process. The quantitative changes in these taxonomic and physiological groups of micro-organisms are studied. The number of micro-organisms from Pseudomonas, Acinetobacter and the bacteria from the xenobiotic-catabolizing complex considerably increased with the individual and the combined effect of the xenobiotics oNP, PCP and oNP PCP. At the same time the toxic shock leads to a remarkable reduction of NH[sub 3] releasing, nitrifying bacteria and those from family Enterobacteriaceae. It is ascertained that the number of Ciliata, Flagellata apochromata, Oligochaeta and Rotatoria is strongly decreased in the series of samples treated with xenobiotics. The leading role of micro-organisms in the real detoxification of hazardous pollutants was experimentally confirmed by research.« less

Anaerobic co-digestion of sewage sludge and food waste.

PubMed

Prabhu, Meghanath S; Mutnuri, Srikanth

2016-04-01

Anaerobic co-digestion of organic matter improves digester operating characteristics and its performance. In the present work, food waste was collected from the institute cafeteria. Two types of sludge (before centrifuge and after centrifuge) were collected from the fluidised bed reactor of the institute treating sewage wastewater. Food waste and sludge were studied for their physico-chemical characteristics, such as pH, chemical oxygen demand, total solids, volatile solids, ammoniacal nitrogen, and total nitrogen. A biomethane potential assay was carried out to find out the optimum mixing ratio of food waste and sludge for anaerobic co-digestion. Results indicated that food waste mixed with sludge in the ratio of 1:2 produced the maximum biogas of 823 ml gVS(-1)(21 days) with an average methane content of 60%. Batch studies were conducted in 5 L lab-glass reactors at a mesophilic temperature. The effect of different substrate loading rates on biogas production was investigated. The mixing ratio of food waste and sludge was 1:2. A loading rate of 1 gVS L d(-1)gave the maximum biogas production of 742 ml g(-1)VS L d(-1)with a methane content of 50%, followed by 2 gVS L d(-1)with biogas of 539 ml g(-1)VS L d(-1) Microbial diversity of the reactor during fed batch studies was investigated by terminal restriction fragment length polymorphism. A pilot-scale co-digestion of food waste and sludge (before centrifuge) indicated the process stability of anaerobic digestion. © The Author(s) 2016.

Pretreatment of high solid microbial sludges

DOEpatents

Rivard, Christopher J.; Nagle, Nicholas J.

1998-01-01

A process and apparatus for pretreating microbial sludges in order to enhance secondary anaerobic digestion. The pretreatment process involves disrupting the cellular integrity of municipal sewage sludge through a combination of thermal, explosive decompression and shear forces. The sludge is pressurized and pumped to a pretreatment reactor where it is mixed with steam to heat and soften the sludge. The pressure of the sludge is suddenly reduced and explosive decompression forces are imparted which partially disrupt the cellular integrity of the sludge. Shear forces are then applied to the sludge to further disrupt the cellular integrity of the sludge. Disrupting cellular integrity releases both soluble and insoluble organic constituents and thereby renders municipal sewage sludge more amenable to secondary anaerobic digestion.

Impact of Coagulant and Flocculant Addition to an Anaerobic Dynamic Membrane Bioreactor (AnDMBR) Treating Waste-Activated Sludge.

PubMed

Kooijman, Guido; Lopes, Wilton; Zhou, Zhongbo; Guo, Hongxiao; de Kreuk, Merle; Spanjers, Henri; van Lier, Jules

2017-03-23

In this work, we investigated the effects of flocculation aid (FA) addition to an anaerobic dynamic membrane bioreactor (AnDMBR) (7 L, 35 °C) treating waste-activated sludge (WAS). The experiment consisted of three distinct periods. In period 1 (day 1-86), the reactor was operated as a conventional anaerobic digester with a solids retention time (SRT) and hydraulic retention time (HRT) of 24 days. In period 2 (day 86-303), the HRT was lowered to 18 days with the application of a dynamic membrane while the SRT was kept the same. In period 3 (day 303-386), a cationic FA in combination with FeCl₃ was added. The additions led to a lower viscosity, which was expected to lead to an increased digestion performance. However, the FAs caused irreversible binding of the substrate, lowering the volatile solids destruction from 32% in period 2 to 24% in period 3. An accumulation of small particulates was observed in the sludge, lowering the average particle size by 50%. These particulates likely caused pore blocking in the cake layer, doubling the trans-membrane pressure. The methanogenic consortia were unaffected. Dosing coagulants and flocculants into an AnDMBR treating sludge leads to a decreased cake layer permeability and decreased sludge degradation.

Parasitic contamination in wastewater and sludge samples in Tunisia using three different detection techniques.

PubMed

Khouja, Layla Ben Ayed; Cama, Vitaliano; Xiao, Lihua

2010-06-01

The limited availability of water results in the reuse of wastewater or sludge. The Tunisian wastewater regulatory guidelines have specific limits for ova of helminths (<1 egg/l) but none for protozoan parasites. We assessed the presence and loads of parasites in 20 samples of raw, treated wastewater and sludge collected from six wastewater treatment plants. Samples were tested by microscopy using the modified Bailenger method (MBM), immunomagnetic separation (IMS) followed by immunofluorescent assay microscopy, and PCR and sequence analysis for the protozoa Cryptosporidium and Giardia. The seven samples of raw wastewater had a high diversity of helminth and protozoa contamination. Giardia spp., Entamoeba histolytica/dispar, Entamoeba coli, Ascaris spp., Enterobius vermicularis, and Taenia saginata were detected by MBM, and protozoan loads were greater than helminth loads. Cryptosporidium and Giardia were also detected by IMS microscopy and PCR. Six of the eight samples of treated wastewater had parasites: helminths (n = 1), Cryptosporidium (n = 1), Giardia (n = 4), and Entamoeba (n = 4). Four of five samples of sludge had microscopically detectable parasites, and all had both Cryptosporidium and Giardia. The genotypes and subtypes of Cryptosporidium and Giardia were of both human and animal origin. These findings suggest that it may be important to monitor the presence of protozoan parasites in treated wastewater and sludge in Tunisia.

Reduction of excess sludge production using mechanical disintegration devices.

PubMed

Strünkmann, G W; Müller, J A; Albert, F; Schwedes, J

2006-01-01

The usability of mechanical disintegration techniques for the reduction of excess sludge production in the activated sludge process was investigated. Using three different disintegration devices (ultrasonic homogeniser, stirred media mill, high pressure homogeniser) and different operational parameters of the disintegration, the effect of mechanical disintegration on the excess sludge production and on the effluent quality was studied within a continuously operated, laboratory scale wastewater treatment system with pre-denitrification. Depending on the operational conditions and the disintegration device used, a reduction of excess sludge production of up to 70% was achieved. A combination of mechanical disintegration with a membrane bioreactor process with high sludge age is more energy effective concerning reduction of sludge production than with a conventional activated sludge process at lower sludge ages. Depending on the disintegration parameters, the disintegration has no, or only minor, negative effect on the soluble effluent COD and on the COD-removal capacity of the activated sludge process. Nitrogen-removal was slightly deteriorated by the disintegration, whereas the system used was not optimised for nitrogen removal before disintegration was implemented.

Resource recovery of organic sludge as refuse derived fuel by fry-drying process.

PubMed

Chang, Fang-Chih; Ko, Chun-Han; Wu, Jun-Yi; Wang, H Paul; Chen, Wei-Sheng

2013-08-01

The organic sludge and waste oil were collected from the industries of thin film transistor liquid crystal display and the recycled cooking oil. The mixing ratio of waste cooking oil and organic sludge, fry-drying temperatures, fry-drying time, and the characteristics of the organic sludge pellet grain were investigated. After the fry-drying process, the moisture content of the organic sludge pellet grain was lower than 5% within 25 min and waste cooking oil was absorbed on the dry solid. The fry-drying organic sludge pellet grain was easy to handle and odor free. Additionally, it had a higher calorific value than the derived fuel standards and could be processed into organic sludge derived fuels. Thus, the granulation and fry-drying processes of organic sludge with waste cooking oil not only improves the calorific value of organic sludge and becomes more valuable for energy recovery, but also achieves waste material disposal and cost reduction. Copyright © 2013 Elsevier Ltd. All rights reserved.

On The Relationship between Suspended Solids of Different Size, the Observed Boundary Flux and Rejection Values for Membranes Treating a Civil Wastewater Stream.

PubMed

Stoller, Marco; Pulido, Javier Miguel Ochando; Palma, Luca Di

2014-08-04

Membrane fouling is one of the main issues in membrane processes, leading to a progressive decrease of permeability. High fouling rates strongly reduce the productivity of the membrane plant, and negatively affect the surviving rate of the membrane modules, especially when real wastewater is treated. On the other hand, since selectivity must meet certain target requirements, fouling may lead to unexpected selectivity improvements due to the formation of an additional superficial layer formed of foulants and that act like a selective secondary membrane layer. In this case, a certain amount of fouling may be profitable to the point where selectivity targets were reached and productivity is not significantly affected. In this work, the secondary clarifier of a step sludge recirculation bioreactor treating municipal wastewater was replaced by a membrane unit, aiming at recovering return sludge and producing purified water. Fouling issues of such a system were checked by boundary flux measurements. A simple model for the description of the observed productivity and selectivity values as a function of membrane fouling is proposed.

On The Relationship between Suspended Solids of Different Size, the Observed Boundary Flux and Rejection Values for Membranes Treating a Civil Wastewater Stream

PubMed Central

Stoller, Marco; Pulido, Javier Miguel Ochando; Di Palma, Luca

2014-01-01

Membrane fouling is one of the main issues in membrane processes, leading to a progressive decrease of permeability. High fouling rates strongly reduce the productivity of the membrane plant, and negatively affect the surviving rate of the membrane modules, especially when real wastewater is treated. On the other hand, since selectivity must meet certain target requirements, fouling may lead to unexpected selectivity improvements due to the formation of an additional superficial layer formed of foulants and that act like a selective secondary membrane layer. In this case, a certain amount of fouling may be profitable to the point where selectivity targets were reached and productivity is not significantly affected. In this work, the secondary clarifier of a step sludge recirculation bioreactor treating municipal wastewater was replaced by a membrane unit, aiming at recovering return sludge and producing purified water. Fouling issues of such a system were checked by boundary flux measurements. A simple model for the description of the observed productivity and selectivity values as a function of membrane fouling is proposed. PMID:25093867

Sorption and biodegradability of sludge bacterial extracellular polymers in soil and their influence on soil copper behavior.

PubMed

Zhou, L X; Zhou, S G; Zhan, X H

2004-01-01

Bacterial extracellular polymers (BEP) affect the translocation and fate of organic and inorganic pollutants in terrestrial and aquatic ecosystems. In this study, BEP from activated sludge was compared with sludge dissolved organic matter (DOM) in terms of behavior and effects on the mobilization and bioavailability of Cu in a well-aged Cu-contaminated orchard sandy loam. Addition of sludge BEP (10-200 mg dissolved organic carbon [DOC] L(-1)) to the soil resulted in 1.6- to 12.8-fold-higher soil soluble Cu concentration over the control and 1.3- to 2.2-fold over sludge DOM of the same concentration. Consequently, the Cu uptake by the ryegrass (Lolium perenne L., cv. Target) grown in the soil was increased by 31% due to interval watering of 100 mg DOC L(-1) of sludge BEP solution in a 35-d period. The influence of sludge BEP on mobilizing soil Cu could be maintained as long as 60 d or more, depending on BEP biodegradation status. The findings that sludge BEP promoted Cu mobilization and bioavailability could be attributed to less adsorption of BEP by soil, slow degradation, and higher affinity with Cu. For example, after 3 wk of aerobic incubation, the soluble Cu present in the sludge DOM-treated soil was reduced to about the level of the control, while the concentration of soluble Cu in BEP-treated soil was 6.2 times higher than that in the control. Therefore, sludge BEP could act as a facilitated-transport carrier of Cu. The environmental risk of Cu should receive much attention if BEP is incorporated into soils.

Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation.

PubMed

Julcour Lebigue, Carine; Andriantsiferana, Caroline; N'Guessan Krou; Ayral, Catherine; Mohamed, Elham; Wilhelm, Anne-Marie; Delmas, Henri; Le Coq, Laurence; Gerente, Claire; Smith, Karl M; Pullket, Suangusa; Fowler, Geoffrey D; Graham, Nigel J D

2010-12-01

This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L(-1)). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption-oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles. Copyright © 2010 Elsevier Ltd. All rights reserved.

Study on nickel and vanadium removal in thermal conversion of oil sludge and oil shale sludge

NASA Astrophysics Data System (ADS)

Sombral, L. G. S.; Pickler, A. C.; Aires, J. R.; Riehl, C. A.

2003-05-01

The petroleum refining processes and of oil shale industrialization generate solid and semi-solid residues. In those residues heavy metals are found in concentrations that vary according to the production sector. The destination of those residues is encouraging researches looking for new technologies that reach the specifications of environmental organisms, and are being developed and applied to the industry. In this work it is shown that the heavy metals concentrations, previously in the petroleum oily solid residues and in those of the oils shale, treated by low temperature thermal conversion, obtaining in both cases concentrations below Ippm to Nickel and below 5ppm to vanadium.

Net positive energy wastewater treatment plant via thermal pre-treatment of sludge: A theoretical case study.

PubMed

Farno, Ehsan; Baudez, Jean Christophe; Parthasarathy, Rajarathinam; Eshtiaghi, Nicky

2017-04-16

In a wastewater treatment process, energy is mainly used in sludge handling and heating, while energy is recovered by biogas production in anaerobic digestion process. Thermal pre-treatment of sludge can change the energy balance in a wastewater treatment process since it reduces the viscosity and yield stress of sludge and increases the biogas production. In this study, a calculation based on a hypothetical wastewater treatment plant is provided to show the possibility of creating a net positive energy wastewater treatment plant as a result of implementing thermal pre-treatment process before the anaerobic digester. The calculations showed a great energy saving in pumping and mixing of the sludge by thermal pre-treatment of sludge before anaerobic digestion process.

Isolation of indigenous enteroviruses from chemically treated and dewatered sludge samples.

PubMed Central

Goddard, M R; Bates, J; Butler, M

1982-01-01

Samples of wastewater sludge were examined for infectious enteroviruses before and after they had been chemically conditioned and dewatered. The least virus was recovered from the cake produced by filter pressing of sludge, which had a greatly increased solids content (39 to 45% [wt/vol]) relative to the untreated sludge (4.2 to 6.2% [wt/vol]) and in one plant was at pH 11 due to the lime conditioner used. Conditioning with a cationic polyelectrolyte before dewatering by centrifugation produced a watery sludge (2.7 to 5.3% [wt/vol]) from which high titers of infectious virus were recovered which were often greater than those isolated from the untreated sludge (0.6 to 1.4% [wt/vol]). This was thought to be due to saturation of virus and sludge floc adsorption sites by the polyelectrolyte, resulting in the liberation of virions from the sludge solids. PMID:6295275

Progress report Waste Resources Utilization Program period ending March 31, 1976. [Radiosterilization of sewage sludge for safe application as fertilizer or animal feed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1976-06-01

This report describes the work on the Waste Resources Utilization Program for the quarter ending March 31, 1976. The purpose of this program is to develop technologies to utilize a /sup 137/Cs ..gamma.. source to modify sewage sludge for safe application as a fertilizer or an animal feed supplement. Results are reported from studies in microbiology, virology, and physical-chemical studies. Determinations were made of inactivation rates for Salmonella species, coliforms, and fecal strep in sewage sludge when radiation and thermoradiation were applied while bubbling oxygen through the sludge. Virology studies were continued investigating virucidal characteristics of anaerobically digested sludge. Anothermore » area of study was the dewatering of sewage sludge to reduce the drying time of the sewage sludge in the drying beds. A centrifuge was also installed to dewater treated sludge to approximately 30 percent solids. (auth)« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Newell, D.; Martino, C.

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 thenmore » 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.« less

Treatment of sugar processing industry effluent up to remittance limits: Suitability of hybrid electrode for electrochemical reactor.

PubMed

Sahu, Omprakash

2017-01-01

Sugar industry is an oldest accommodates industry in the world. It required and discharges a large amount of water for processing. Removal of chemical oxygen demand and color through the electrochemical process including hybrid iron and aluminum electrode was examined for the treatment of cane-based sugar industry wastewater. Most favorable condition at pH 6.5, inter-electrode gap 20 mm, current density 156 A m -2 , electrolyte concentration 0.5 M and reaction time 120 min, 90% COD and 93.5% color removal was achieved. The sludge generated after treatment has less organic contain, which can be used as manure in agricultural crops. Overall the electrocoagulation was found to be reliable, efficient and economically fit to treat the sugar industry wastewater. •Electrocoagulation method for sugar processing industry wastewater treatment Optimization of operating parameters for maximum efficiency.•Physicochemical analysis of sludge and scum.•Significance of hydride metal electrode for pollutant removal.

Anaerobic digestion of sewage sludge with grease trap sludge and municipal solid waste as co-substrates.

PubMed

Grosser, A; Neczaj, E; Singh, B R; Almås, Å R; Brattebø, H; Kacprzak, M

2017-05-01

The feasibility of simultaneous treatment of multiple wastes via co-digestion was studied in semi-continuous mode at mesophilic conditions. The obtained results indicated that sewage sludge, organic fraction of municipal waste (OFMSW) and grease trap sludge (GTS) possess complementary properties that can be combined for successful anaerobic digestion. During the co-digestion period, methane yield and VS removal were significantly higher in comparison to digestion of sewage sludge alone. Addition of GTS to digesters treating sewage sludge resulted in increased VS removal and methane yield up to 13% (from 50 to 56.4) and 52% (from 300 to 456,547m 3 /Mg VS add ), respectively. While the use of OFMSW as the next co-substrate in the feedstock, can boost methane yield and VS removal up to 82% (300-547m 3 /Mg VS add ) and approximately 29% (from 50% to 64.7%), respectively. Moreover, the results of the present laboratory study revealed that the addition of co-substrates to the feedstock had a significant influence on biogas composition. During the experiment methane content in biogas ranged from 67% to 69%. While, the concentration of LCFAs was increasing with the gradual increase in the share of co-substrates in the mixtures, wherein only the oleic acid was higher than some inhibition concentrations which have been reported in the literature. However, it did not significantly affect the efficiency of the co-digestion process. Copyright © 2017. Published by Elsevier Inc.

EXPERIENCE WITH IMPLEMENTING FEDERAL AND STATE REQUIREMENTS FOR THE BENEFICIAL USE OF BIOSOLIDS - CONTROLLING PATHOGENS AND VECTOR ATTRACTIVENESS

EPA Science Inventory

This presentation will review as of 2000, the amount of sludge produced in the US, how it is treated, and how much is land applied, land-filled, or incinerated. Details will be given for the commonly employed Class A and B disinfection processes for controlling pathogens; how ext...

Anaerobic-aerobic treatment of purified terephthalic acid (PTA) effluent; a techno-economic alternative to two-stage aerobic process.

PubMed

Pophali, G R; Khan, R; Dhodapkar, R S; Nandy, T; Devotta, S

2007-12-01

This paper addresses the treatment of purified terephthalic acid (PTA) effluent using anaerobic and aerobic processes. Laboratory studies were carried out on flow proportionate composite wastewater generated from the manufacturing of PTA. An activated sludge process (ASP-two stage and single stage) and an upflow anaerobic fixed film fixed bed reactor (AFFFBR) were used, individually and in combination. The performance of a full-scale ETP under existing operating conditions was also studied. Full scale ETP studies revealed that the treatment of PTA effluent using a two-stage ASP alone does not meet treated effluent quality within the prescribed Indian Standards. The biomass produced in the two stage ASP was very viscous and fluffy and the sludge volume index (SVI) was very high (200-450 ml/g). However, pretreatment of PTA effluent using an upflow AFFFBR ensured substantial reduction in BOD (63%) and COD (62%) with recovery of biogas at 1.8-1.96 l/l effluent treated at a volumetric loading rate (VLR) 4-5 kg COD/m(3) d. The methane content in the biogas varied between 55% and 60%. The pretreated effluent from the upflow AFFFBR was then treated through a single stage ASP. The biomass produced in the ASP after anaerobic treatment had very good settlability (SVI: 75-90 ml/g) as compared to the two stage ASP and the treated effluent quality with respect to BOD, COD and SS was within the prescribed Indian Standards. The alternative treatment process comprising an upflow AFFFBR and a single stage ASP ensured net power saving of 257 kW and in addition generated 442 kW of power through the AFFFBR.

Pretreatment of high solid microbial sludges

DOEpatents

Rivard, C.J.; Nagle, N.J.

1998-07-28

A process and apparatus are disclosed for pretreating microbial sludges in order to enhance secondary anaerobic digestion. The pretreatment process involves disrupting the cellular integrity of municipal sewage sludge through a combination of thermal, explosive decompression and shear forces. The sludge is pressurized and pumped to a pretreatment reactor where it is mixed with steam to heat and soften the sludge. The pressure of the sludge is suddenly reduced and explosive decompression forces are imparted which partially disrupt the cellular integrity of the sludge. Shear forces are then applied to the sludge to further disrupt the cellular integrity of the sludge. Disrupting cellular integrity releases both soluble and insoluble organic constituents and thereby renders municipal sewage sludge more amenable to secondary anaerobic digestion. 1 fig.

Full scale implementation of the nutrient limited BAS process at Södra Cell Värö.

PubMed

Malmqvist, A; Berggren, B; Sjölin, C; Welander, T; Heuts, L; Fransén, A; Ling, D

2004-01-01

A combination of the suspended carrier biofilm process and the activated sludge process (biofilm-activated sludge--BAS) has been shown to be very successful for the treatment of different types of pulp and paper mill effluents. The robust biofilm pre-treatment in combination with activated sludge results in a stable, compact and highly efficient process. Recent findings have shown that nutrient limited operation of the biofilm process greatly improves the sludge characteristics in the following activated sludge stage, while minimising sludge production and effluent discharge of nutrients. The nutrient limited BAS process was implemented at full scale at the Södra Cell Värö kraft mill and taken into operation in July 2002. After start-up and optimisation over about 5 months, the process meets all effluent discharge limits. The removal of COD is close to 70% and the removal of EDTA greater than 90%. Typical effluent concentrations of suspended solids and nutrients during stable operations have been 20-30 mg/L TSS, 0.3-0.5 mg/L phosphorus and 3-5 mg/L nitrogen. The sludge production was 0.09 kgSS/kg COD removed and the sludge volume index was 50-100 mL/g.

[Assessing environmental and economical benefits of integrated sewage treatment systems].

PubMed

Li, Jin-rong; Zhang, Xiao-hong; Zhang, Hang-bin; Pan, Heng-yu; Liu, Qiang

2015-08-01

Sewage treatment, treated water treatment and sludge treatment are three basic units of an integrated sewage treatment system. This work assessed the influence of reusing or discharge of treated water and sludge landfill or compost on the sustainability of an integrated sewage treatment system using emergy analysis and newly proposed emergy indicators. This system's value included its environmental benefits and the products. Environmental benefits were the differences of the environmental service values before and after sewage treatment. Due to unavailability of data of the exchanged substance and energy in the internal system, products' values were attained by newly proposed substitution values. The results showed that the combination of sewage treatment, treated water reuse and sludge landfill had the strongest competitiveness, while the combination of sewage treatment, treated water reuse and earthworm compost was the most sustainable. Moreover, treated water reuse and earthworm compost were helpful for improving the sustainability of the integrated sewage treatment system. The quality of treated water and local conditions should be also considered when implementing the treated water reuse or discharge. The resources efficiency of earthworm compost unit needed to be further improved. Improved emergy indices were more suitable for integrated sewage treatment systems.

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

NASA Astrophysics Data System (ADS)

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.

Transformation of PVP coated silver nanoparticles in a simulated wastewater treatment process and the effect on microbial communities

PubMed Central

2013-01-01

Background Manufactured silver nanoparticles (AgNPs) are one of the most commonly used nanomaterials in consumer goods and consequently their concentrations in wastewater and hence wastewater treatment plants are predicted to increase. We investigated the fate of AgNPs in sludge that was subjected to aerobic and anaerobic treatment and the impact of AgNPs on microbial processes and communities. The initial identification of AgNPs in sludge was carried out using transmission electron microscopy (TEM) with energy dispersive X-ray (EDX) analysis. The solid phase speciation of silver in sludge and wastewater influent was then examined using X-ray absorption spectroscopy (XAS). The effects of transformed AgNPs (mainly Ag-S phases) on nitrification, wastewater microbial populations and, for the first time, methanogenesis was investigated. Results Sequencing batch reactor experiments and anaerobic batch tests, both demonstrated that nitrification rate and methane production were not affected by the addition of AgNPs [at 2.5 mg Ag L-1 (4.9 g L-1 total suspended solids, TSS) and 183.6 mg Ag kg -1 (2.9 g kg-1 total solids, TS), respectively]. The low toxicity is most likely due to AgNP sulfidation. XAS analysis showed that sulfur bonded Ag was the dominant Ag species in both aerobic (activated sludge) and anaerobic sludge. In AgNP and AgNO3 spiked aerobic sludge, metallic Ag was detected (~15%). However, after anaerobic digestion, Ag(0) was not detected by XAS analysis. Dominant wastewater microbial populations were not affected by AgNPs as determined by DNA extraction and pyrotag sequencing. However, there was a shift in niche populations in both aerobic and anaerobic sludge, with a shift in AgNP treated sludge compared with controls. This is the first time that the impact of transformed AgNPs (mainly Ag-S phases) on anaerobic digestion has been reported. Conclusions Silver NPs were transformed to Ag-S phases during activated sludge treatment (prior to anaerobic digestion). Transformed AgNPs, at predicted future Ag wastewater concentrations, did not affect nitrification or methanogenesis. Consequently, AgNPs are very unlikely to affect the efficient functioning of wastewater treatment plants. However, AgNPs may negatively affect sub-dominant wastewater microbial communities. PMID:23497481

Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review

PubMed Central

Gebreeyessus, Getachew D.; Jenicek, Pavel

2016-01-01

During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs) is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD) of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH). In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so as to optimize the connection between the two systems. In addition, many other relevant AD process parameters, including sludge rheology, which need to be addressed, are also reviewed and presented. PMID:28952577

Interpretation of the characteristics of ocean-dumped sewage sludge related to remote sensing

NASA Technical Reports Server (NTRS)

Pagoria, P. S.; Kuo, C. Y.

1979-01-01

Wastewater sludge characteristics in general, and characteristics of wastewater sludges generated by the City of Philadelphia in particular, were addressed. The types and sources of wastewater sludges, a description of sludge treatment and disposal processes, examination of sludge generation and management for the City of Philadelphia, and definition of characteristics for typical east coast sludges undergoing ocean disposal were discussed. Specific differences exist between the characteristics of primary and secondary wastewater sludges, especially with the nature and size distribution of the solids particles. The sludges from the City of Philadelphia monitored during remote sensing experiments were mixtures of various sludge types and lacked distinguishing characteristics. In particular, the anaerobic digestion process exerted the most significant influence on sludge characteristics for the City of Philadelphia. The sludges generated by the City of Philadelphia were found to be typical and harbor no unique features.

Persistence of enteroviruses in sewage sludge*

PubMed Central

Subrahmanyan, T. P.

1977-01-01

Sewage from residential areas often contains viruses pathogenic for man and significant amounts are probably associated with solids in sewage sludge. Information on the survival of viruses in sewage sludge is necessary in order to develop guidelines for recycling programmes that involve spreading the sludge on land. In the present study, a number of enteroviruses were added to sewage sludge and the artificially contaminated sludges were tested for viruses at intervals over a 12-week period. Most of the viruses survived for many weeks at room temperature. It is clear that sewage sludge destined for land application should be adequately treated for virus inactivation. In interpreting these results, it should be borne in mind that the survival of hepatitis A virus might be similar. Recent reports about the reappearance of poliomyelitis in regions with immunization programmes should also be taken into consideration. PMID:202416

BIOMARKERS OF VIRAL EXPOSURE

EPA Science Inventory

Viral and protozoan pathogens associated with raw sludge can cause encephalitis, gastroenteritis, hepatitis, myocarditis, and a number of other diseases. Raw sludge that has been treated to reduce these pathogens can be used for land application according to the regulations spec...

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

PubMed

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.

Ternary blends containing demercurated lighting phosphor and MSWI fly ash as high-performance binders for stabilizing and recycling electroplating sludge.

PubMed

Huang, Wu-Jang; Wu, Chia-Teng; Wu, Chang-En; Hsieh, Lin-Huey; Li, Chang-Chien; Lain, Chi-Yuan; Chu, Wei

2008-08-15

This paper describes the solidification and stabilization of electroplating sludge treated with a high-performance binder made from portland type-I cement, municipal solid waste incineration fly ash, and lighting phosphor powder (called as cement-fly ash-phosphor binder, CFP). The highest 28-day unconfined compressive strength of the CFP-treated paste was 816 kg/cm(2) at a ratio of cement to fly ash to lighting phosphor powder of 90:5:5; the strength of this composition also fulfilled the requirement of a high-strength concrete (>460 kg/cm(2) at 28 days). The CFP-stabilized sludge paste samples passed the Taiwanese EPA toxicity characteristic leaching procedure test and, therefore, could be used either as a building material or as a controlled low-strength material, depending on the sludge-to-CFP binder ratio.

Combination of alkaline and microwave pretreatment for disintegration of meat processing wastewater sludge.

PubMed

Erden, G

2013-01-01

Meat processing wastewater sludge has high organic content but it is very slow to degrade in biological processes. Anaerobic digestion may be a good alternative for this type of sludge when the hydrolysis, known to be the rate-limiting step of biological sludge anaerobic degradation, could be eliminated by disintegration. This investigation deals with disintegration of meat processing wastewater sludge. Microwave (MW) irradiation and combined alkaline pretreatment and MW irradiation were applied to sludge for disintegration purposes. Disintegration performance of the methods was evaluated with disintegration degree based on total and dissolved organic carbon calculations (DD(TOC)), and the solubilization of volatile solids (S(VS)) in the pretreated sludge. Optimum conditions were found to be 140 degrees C and 30 min for MW irradiation using response surface methodology (RSM) and pH = 13 for combined pretreatment. While DD(TOC) was observed as 24.6% and 54.9, S(VS) was determined as 8.54% and 42.5% for MW pretreated and combined pretreated sludge, respectively. The results clearly show that pre-conditioning of sludge with alkaline pretreatment played an important role in enhancing the disintegration efficiency of subsequent MW irradiation. Disintegration methods also affected the anaerobic biodegradability and dewaterability of sludge. An increase of 23.6% in biogas production in MW irradiated sludge was obtained, comparing to the raw sludge at the end of the 35 days of incubation. This increase was observed as 44.5% combined pretreatment application. While MW pretreatment led to a little improvement of the dewatering performance of sludge, in combined pretreatment NaOH deteriorates the sludge dewaterability.

On the understanding and control of the spontaneous heating of dried tannery wastewater sludge.

PubMed

Biasin, A; Della Zassa, M; Zerlottin, M; Refosco, D; Bertani, R; Canu, P

2014-04-01

We studied the spontaneous heating of dried sludge produced by treating wastewater mainly originating from tanneries. Heating up to burning has been observed in the presence of air and moisture, starting at ambient temperature. To understand and prevent the process we combined chemical and morphological analyses (ESEM) with thermal activity monitoring in insulated vessels. Selective additions of chemicals, either to amplify or depress the reactivity, have been used to investigate and identify both the chemical mechanism causing the sludge self-heating, and a prevention or a mitigation strategy. FeS additions accelerate the onset of reactivity, while S sustains it over time. On the contrary, Ca(OH)2, Na2CO3, NaHCO3, FeCl2, EDTA, NaClO can limit, up to completely preventing, the exothermic activity. All the experimental evidences show that the reactions supporting the dried sludge self-heating involve the Fe/S/O system. The total suppression of the reactivity requires amounts of additives that are industrially incompatible with waste reduction and economics. The best prevention requires reduction or removal of S and Fe from the dried solid matrix. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prediction of anaerobic biodegradability and bioaccessibility of municipal sludge by coupling sequential extractions with fluorescence spectroscopy: towards ADM1 variables characterization.

PubMed

Jimenez, Julie; Gonidec, Estelle; Cacho Rivero, Jesús Andrés; Latrille, Eric; Vedrenne, Fabien; Steyer, Jean-Philippe

2014-03-01

Advanced dynamic anaerobic digestion models, such as ADM1, require both detailed organic matter characterisation and intimate knowledge of the involved metabolic pathways. In the current study, a methodology for municipal sludge characterization is investigated to describe two key parameters: biodegradability and bioaccessibility of organic matter. The methodology is based on coupling sequential chemical extractions with 3D fluorescence spectroscopy. The use of increasingly strong solvents reveals different levels of organic matter accessibility and the spectroscopy measurement leads to a detailed characterisation of the organic matter. The results obtained from testing 52 municipal sludge samples (primary, secondary, digested and thermally treated) showed a successful correlation with sludge biodegradability and bioaccessibility. The two parameters, traditionally obtained through the biochemical methane potential (BMP) lab tests, are now obtain in only 5 days compared to the 30-60 days usually required. Experimental data, obtained from two different laboratory scale reactors, were used to validate the ADM1 model. The proposed approach showed a strong application potential for reactor design and advanced control of anaerobic digestion processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhancing post aerobic digestion of full-scale anaerobically digested sludge using free nitrous acid pretreatment.

PubMed

Wang, Qilin; Zhou, Xu; Peng, Lai; Wang, Dongbo; Xie, Guo-Jun; Yuan, Zhiguo

2016-05-01

Post aerobic digestion of anaerobically digested sludge (ADS) has been extensively applied to the wastewater treatment plants to enhance sludge reduction. However, the degradation of ADS in the post aerobic digester itself is still limited. In this work, an innovative free nitrous acid (HNO2 or FNA)-based pretreatment approach is proposed to improve full-scale ADS degradation in post aerobic digester. The post aerobic digestion was conducted by using an activated sludge to aerobically digest ADS for 4 days. Degradations of the FNA-treated (treated at 1.0 and 2.0 mg N/L for 24 h) and untreated ADSs were then determined and compared. The ADS was degraded by 26% and 32%, respectively, in the 4-day post aerobic digestion period while being pretreated at 1.0 and 2.0 mg HNO2-N/L. In comparison, only 20% of the untreated ADS was degraded. Economic analysis demonstrated that the implementation of FNA pretreatment can be economically favourable or not depending on the sludge transport and disposal cost. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modelling the structure of sludge aggregates

PubMed Central

Smoczyński, Lech; Ratnaweera, Harsha; Kosobucka, Marta; Smoczyński, Michał; Kalinowski, Sławomir; Kvaal, Knut

2016-01-01

ABSTRACT The structure of sludge is closely associated with the process of wastewater treatment. Synthetic dyestuff wastewater and sewage were coagulated using the PAX and PIX methods, and electro-coagulated on aluminium electrodes. The processes of wastewater treatment were supported with an organic polymer. The images of surface structures of the investigated sludge were obtained using scanning electron microscopy (SEM). The software image analysis permitted obtaining plots log A vs. log P, wherein A is the surface area and P is the perimeter of the object, for individual objects comprised in the structure of the sludge. The resulting database confirmed the ‘self-similarity’ of the structural objects in the studied groups of sludge, which enabled calculating their fractal dimension and proposing models for these objects. A quantitative description of the sludge aggregates permitted proposing a mechanism of the processes responsible for their formation. In the paper, also, the impact of the structure of the investigated sludge on the process of sedimentation, and dehydration of the thickened sludge after sedimentation, was discussed. PMID:26549812

Full-scale effects of addition of sludge from water treatment stations into processes of sewage treatment by conventional activated sludge.

PubMed

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.

Impact of liming and drying municipal sewage sludge on the amount and availability of (14)C-acetyl sulfamethoxazole and (14)C-acetaminophen residues.

PubMed

Geng, Chunnu; Bergheaud, Valérie; Garnier, Patricia; Zhu, Yong-Guan; Haudin, Claire-Sophie

2016-01-01

Acetyl Sulfamethoxazole (AC-SMX) and acetaminophen (ACM) can be found in municipal sewage sludge, and their content and availability may be influenced by sludge treatments, such as drying and liming. A sludge similarly centrifuged with/without a flocculant was spiked with (14)C-labelled AC-SMX or ACM. Then, it was either limed (20% CaO) or/and dried under different laboratory conditions (1 week at ambient temperature; and 48 h at 40 or 80 °C). The total amount and distribution of the (14)C-compounds among several chemical fractions, based on the sludge floc definition, were assessed at the end of the treatments. All the (14)C-activity brought initially was recovered in the limed and/or dried sludges for AC-SMX but only between 44.4 and 84.9% for ACM, with the highest rate obtained for the limed sludge. Drying at 80 °C or liming increased the percentage of the sludge total organic carbon recovered in the extracts containing soluble extracellular polymeric substances (S-EPS) and the percentage of the total (14)C-activity extracted simultaneously. The non-extractable residues represented only 3.9-11.6% of the total (14)C-activity measured in the treated sludges for AC-SMX and 16.9-21.8% for ACM. The presence of AC-SMX and ACM residues in the treated sludges, after liming and drying under different conditions, was shown using some (14)C-labelled molecules. At this time scale and according to the extraction method selected, most of the (14)C-residues remained soluble and easily extractable for both compounds. This result implies that certain precautions should be taken when storing sludges before being spread on the field. Sludge piles, particularly the limed sludge, should be protected from rain to limit the production of lixiviates, which may contain residues of AC-SMX and ACM. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of endocrine-disrupting chemicals and conventional pollutants in a continuous-operating activated sludge process integrated with ozonation for excess sludge reduction.

PubMed

Nie, Yafeng; Qiang, Zhimin; Ben, Weiwei; Liu, Junxin

2014-06-01

Sludge ozonation is considered as a promising technology to achieve a complete reduction of excess sludge, but as yet its effects on the removal of endocrine-disrupting chemicals (EDCs) and conventional pollutants (i.e., COD, N and P) in the activated sludge process are still unclear. In this study, two lab-scale continuous-operating activated sludge treatment systems were established: one was operated in conjunction with ozonation for excess sludge reduction, and the other was operated under normal conditions as control. The results indicate that an ozone dose of 100 mg O₃ g(-1)SS led to a zero yield of excess sludge in the sludge-reduction system during a continuous-operating period of 45d. Although ozonation gave a relatively lower specific oxygen uptake rate of activated sludge, it had little effect on the system's removal performance of COD and nitrogen substances. As a plus, sludge ozonation contributed a little more removal of target EDCs (estrone, 17β-estrodiol, estriol, 17α-ethinylestradiol, bisphenol A, and 4-nonylphenol). However, the total phosphorus removal declined notably due to its accumulation in the sludge-reduction system, which necessitates phosphorus recovery for the activated sludge process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Irradiation of municipal sludge for agricultural use

NASA Astrophysics Data System (ADS)

Ahlstrom, Scott B.

Research has demonstrated that irradiation is an effective means for reducing pathogens in sewage sludge to levels where sludge reuse in public areas meets criteria for protection of the public health. Complementary research has demonstrated the value of the irradiated sludge in both agronomic and animal science applications. The benefits of sludge application to cropland are well documented. The irradiation process does not increase the extractability and plant uptake of a broad range of nutrients and heavy metals from sludge-amended soils. However, it does eliminate the hazards associated with pathogen contamination when applying sludge to agricultural land. Irradiated sludge has also been evaluated as a supplemental foodstuff for cattle and sheep. The data indicate that products derived from raw sewage may have a substantial nutritive value for ruminant animals. Irradiation of sewage sludge is a practical means of sludge disinfection. Where a highly disinfected sludge is required, it should be considered as a viable sludge management alternative. Evaluation of sludge irradiation technology and its associated costs must be done with consideration of other sludge treatment processes to develop an acceptable sludge management system.

Energy and nutrient recovery from anaerobic treatment of organic wastes

NASA Astrophysics Data System (ADS)

Henrich, Christian-Dominik

The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an "Ammonia Recovery Process" (ARP) consisting of: (1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, (2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, (3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, (4) high-rate algal post-treatment and finally, (5) an optional anaerobic digestion process for algal and bacterial biomass, and/or supplemental waste fermentation providing the potential for additional nutrient and energy recovery. In addition, the value provided by the waste treatment function of the overall processes, each of the sub-processes would provide valuable co-products offering potential GHG credit through direct fossil-fuel replacement, or replacement of products requiring fossil fuels. These valuable co-products include, (1) ammonium sulfate fertilizer, (2) bacterial biomass, (3) algal biomass providing, high-protein feeds and oils for biodiesel production and, (4) methane bio-fuels. Laboratory and pilot reactors were constructed and operated, providing data supporting the quantification and modeling of the ARP. Growth parameters, and stoichiometric coefficients were determined, allowing for design of the leachate activated sludge treatment sub-component. Laboratory and pilot algal reactors were constructed and operated, and provided data that supported the determination of leachate organic/inorganic-nitrogen ratio, and loading rates, allowing optimum performance of high-rate algal post-treatment. A modular and expandable computer program was developed, which provided a systems model framework capable of predicting individual component and overall performance. The overall systems model software, ENRAT, predicted that a full-scale operation to treat 18,750 L leachate/day would need an Ammonia Recovery process consisting of 88,300 L of total gas transfer column volume, an activated sludge system of 74,417 L, and an algal post treatment raceway of 683 m2 (30 cm depth). The ARP would consume 262.5 L/day of 6N sulfuric acid and produce 16.12 kg-N/day ammonium sulfate. The activated sludge system and algal post treatment would produce 900 g-VS/day (or 44.6 L 2% sludge) and 6.83 kg-VS/day (or 341.6 L 2% sludge) of bacterial and algal biomass.

Optimizing dewaterability of drinking water treatment sludge by ultrasound treatment: Correlations to sludge physicochemical properties.

PubMed

Meng, Zhili; Zhou, Zhiwei; Zheng, Dan; Liu, Lujian; Dong, Jun; Yang, Yanling; Li, Xing; Zhang, Tingting

2018-07-01

Sludge dewatering has proven to be an effective method to reduce the volume of sludge. In this study, drinking water treatment sludge (DWTS) was treated by ultra-sonication under variable conditions comparing two sonoreactor types (bath and probe), four frequencies (25, 40, 68, 160 kHz) and four energy density levels (0.03, 1, 3, 5 W/mL). The effects of these conditions were studied using specific resistance to filtration and capillary suction time as measures of dewaterability, and floc size, the Brunauer, Emmett and Teller (BET) specific surface area and Zeta potential to determine treated sludge characteristics. The results indicated that the dewaterability of sonicated sludge improved at relatively low energy densities of 0.03 and 1.0 W/mL, while an optimum for sonication duration (within 10 min) was also identified. Higher frequencies (tested up to 160 kHz) with acoustic energy density of 0.03 W/mL also reduced the dewatering property. At higher energy densities of 3.0 and 5.0 W/mL, dewaterability of sludge deteriorated regardless of ultra-sonication time, with an increase of solubilized organic matter content and severely changed floc characteristics. The deterioration of the dewatering capacity was closely related to the considerably reduced floc sizes, dissolution of proteins and polysaccharides, and to the Zeta potential of sonicated sludge flocs. The dewaterability was not correlated with BET specific surface area. Mechanistic explanations for the observations were discussed by analyzing corrosion patterns of aluminum foil as a measure for cavitation field distribution. Copyright © 2018 Elsevier B.V. All rights reserved.

Improving material and energy recovery from the sewage sludge and biomass residues.

PubMed

Kliopova, Irina; Makarskienė, Kristina

2015-02-01

Sewage sludge management is a big problem all over the world because of its large quantities and harmful impact on the environment. Energy conversion through fermentation, compost production from treated sludge for agriculture, especially for growing energetic plants, and treated sludge use for soil remediation are widely used alternatives of sewage sludge management. Recently, in many EU countries the popularity of these methods has decreased due to the sewage sludge content (heavy metals, organic pollutions and other hazards materials). This paper presents research results where the possibility of solid recovered fuel (SRF) production from the separate fraction (10-40 mm) of pre-composted materials--sewage sludge from municipal waste water treatment plant and biomass residues has been evaluated. The remaining fractions of pre-composted materials can be successfully used for compost or fertiliser production, as the concentration of heavy metals in the analysed composition is reduced in comparison with sewage sludge. During the experiment presented in this paper the volume of analysed biodegradable waste was reduced by 96%: about 20% of input biodegradable waste was recovered to SRF in the form of pellets with 14.25 MJ kg(-1) of the net calorific value, about 23% were composted, the rest--evaporated and discharged in a wastewater. The methods of material-energy balances and comparison analysis of experiment data have been chosen for the environmental impact assessment of this biodegradable waste management alternative. Results of the efficiency of energy recovery from sewage sludge by SRF production and burning, comparison analysis with widely used bio-fuel-sawdust and conclusions made are presented. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sorption of Perfluorinated Compounds onto different types of sewage sludge and assessment of its importance during wastewater treatment.

PubMed

Arvaniti, Olga S; Andersen, Henrik R; Thomaidis, Nikolaos S; Stasinakis, Athanasios S

2014-09-01

The distribution coefficient (Kd) and the organic carbon distribution coefficient (KOC) were determined for four Perfluorinated Compounds (PFCs) to three different types of sludge taken from a conventional Sewage Treatment Plant (STP). Batch experiments were performed in six different environmental relevant concentrations (200ngL(-1)to 5μgL(-1)) containing 1gL(-1) sludge. Kd values ranged from 330 to 6015, 329 to 17432 and 162 to 11770Lkg(-1) for primary, secondary and digested sludge, respectively. The effects of solution's pH, ionic strength and cation types on PFCs sorption were also evaluated. Sorption capacities of PFCs significantly decreased with increased pH values from 6 to 8. Furthermore, the divalent cation (Ca(2+)) enhanced PFCs sorption to a higher degree in comparison with the monovalent cation (Na(+)) at the same ionic strength. The obtained Kd values were applied to estimate the sorbed fractions of each PFC in different stages of a typical STP and to calculate their removal through treated wastewater and sludge. In primary settling tank, the predicted sorbed fractions ranged from 3% for Perfluorooctanoic Acid (PFOA) to 55% for Perfluoroundecanoic acid (PFUdA), while in activated sludge tank and anaerobic digester sorption was more than 50% for all target compounds. Almost 86% of initial PFOA load is expected to be detected in treated wastewater; while Perfluorodecanoic acid (PFDA), PFUdA and Perfluorooctanesulfonate (PFOS) can be significantly removed (>49%) via sorption to primary and excess secondary sludge. In anaerobic digester, the major part (>76%) of target PFCs is expected to be sorbed to sludge, while almost 3% of initial PFOA load will be detected in sludge leachates. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potentials of an integrated biomass utilization system: Estimation of carbon flow and energy consumption

NASA Astrophysics Data System (ADS)

Suzuki, Ryosuke; Nishimura, Motoki; Yuan, Lee Chang; Kamahara, Hirotsugu; Atsuta, Yoichi; Daimon, Hiroyuki

2017-10-01

Utilization of sewage sludge using anaerobic digestion has been promoted for decades. However, it is still relatively uncommon especially in Japan. As an approach to promote the utilization of sewage sludge using anaerobic digestion, an integrated system that combines anaerobic digestion with greenhouse, composting and seaweed cultivation was proposed. Based on the concept of the integrated system, not only sewage sludge can be treated using anaerobic digestion that creates green energy, but also the by-products such as CO2 and heat produced during the process can be utilized for crops production. In this study, the potentials of such integrated system were discussed through the estimation of possible commercialized scale as well as comparison of energy consumption with conventional approach for sewage sludge treatment, which is the incineration. The estimation of possible commercialized scale was calculated based on the carbon flow of the system. Results showed that 25% of the current total electricity of the wastewater treatment plant can be covered by the energy produced using anaerobic digestion of sewage sludge. It was estimated that the total energy consumption of the integrated system was actually 14% lower when compared to incineration approach. In addition to the large amount of crops that can be produced, all in all this study aimed to be the showcase of the potentials of sewage sludge as a biomass by implementing the proposed integrated system. The extra values of producing crops through the utilization of CO2 and heat can serve as a stimulus to the public, which would surely lead to higher interest to implement the utilization of sewage sludge using anaerobic digestion.

Accelerated solvent extraction combined with solid phase extraction for the determination of organophosphate esters from sewage sludge compost by UHPLC-MS/MS.

PubMed

Pang, Long; Yang, Peijie; Ge, Liming; Du, Jingjing; Zhang, Hongzhong

2017-02-01

Organophosphate esters (OPEs), widely used as flame retardants and plasticizers, are regarded as emerging pollutants. OPEs are prone to concentrate into residual activated sludge, which might cause secondary pollution if not suitably treated. Composting is an economical and effective approach to make sewage sludge stable and harmless. Therefore, it is essential to develop a novel method for analyzing OPEs in sewage sludge compost samples. However, in the composting process, large amounts of amendments are doped into the sludge to adjust the carbon-nitrogen ratio. Amendment has a strong capacity for adsorption and thus induces a decrease of extraction efficiency. This study developed a novel procedure for determining OPEs in compost samples. Accelerated solvent extraction (ASE) and solid phase extraction (SPE) were used for extracting and concentrating the OPEs from sewage sludge compost samples, and then analyzed by UHPLC-MS/MS. Some parameters were optimized in this study, mainly including the extraction solvent type, extraction temperature, static extraction time, extraction cycles, and flush volume. Under the optimal conditions, the proposed method showed good linearity between 0.50 and 100 μg kg -1 with regression coefficients in the range of 0.9984-0.9998. Detection limits were in the range of 0.02-3 μg kg -1 with standard deviations ranging from 2 to 6%. Acceptable recoveries between 56 and 119% for samples spiked at different concentration levels were achieved. In contrast, the recoveries merely ranged from 24 to 58% by using ultrasonic-assisted extraction. Graphical abstract A comparison of recoveries between ultrasonic-assisted extraction (UAS) and accelerated solvent extraction (ASE) for organophosphate esters from sewage sludge compost samples.

Heterogeneous catalytic ozonation of biologically pretreated Lurgi coal gasification wastewater using sewage sludge based activated carbon supported manganese and ferric oxides as catalysts.

PubMed

Zhuang, Haifeng; Han, Hongjun; Hou, Baolin; Jia, Shengyong; Zhao, Qian

2014-08-01

Sewage sludge of biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl₂ as activation agent, which supported manganese and ferric oxides as catalysts (including SBAC) to improve the performance of ozonation of real biologically pretreated Lurgi coal gasification wastewater. The results indicated catalytic ozonation with the prepared catalysts significantly enhanced performance of pollutants removal and the treated wastewater was more biodegradable and less toxic than that in ozonation alone. On the basis of positive effect of higher pH and significant inhibition of radical scavengers in catalytic ozonation, it was deduced that the enhancement of catalytic activity was responsible for generating hydroxyl radicals and the possible reaction pathway was proposed. Moreover, the prepared catalysts showed superior stability and most of toxic and refractory compounds were eliminated at successive catalytic ozonation runs. Thus, the process with economical, efficient and sustainable advantages was beneficial to engineering application. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exploring the potential of anaerobic sulfate reduction process in treating sulfonated diazo dye: Microbial community analysis using bar-coded pyrosequencing.

PubMed

Rasool, Kashif; Shahzad, Asif; Lee, Dae Sung

2016-11-15

Anaerobic decolorization and biotransformation of azo dye was investigated in a sulfate-reducing environment. Batch reactor studies were performed with mixed cultures of anaerobic sulfate-reducing bacteria (SRBs) enriched from anaerobic digester sludge. Complete sulfate and color removal were achieved in batch experiments with different initial dye concentrations (50-2500mg/L) and 1000mg/L of sulfate. Induction of various oxidoreductive enzyme activities such as phenol oxidase, veratryl alcohol oxidase, lignin peroxidase, and azo reductase was studied to understand their involvement in dye metabolism under anoxic environment. The degradation of Cotton Red B was confirmed using high-performance liquid chromatography and gas chromatography-mass spectroscopy. Sulfidogenic sludge demonstrated excellent dye degradation and mineralization ability, producing aniline and 1,4-diamino benzene as metabolites. A barcoded 16S rRNA gene-pyrosequencing approach was used to assess the bacterial diversity in the sludge culture and a phylogenetic tree was constructed for sulfate-reducing bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

Stabilization of waste-activated sludge through the anoxic-aerobic digestion process.

PubMed

Hashimoto, S; Fujita, M; Terai, K

1982-08-01

During the aerobic digestion process, the nitrogen which had been embedded in the activated sludge is solubilized to form ammoniacal and nitric nitrogen which are in turn transferred to the liquor and cause the increase of nitrogen loading in the sewage treatment plant. In this study, the anoxic-aerobic sludge digestion system which is a modified form of the conventional aerobic sludge digestion is made up of aerobic and anoxic tanks and are designed to remove both the volatile suspended solids and the total nitrogen (TN) simultaneously. The removal efficiencies of both VSS and TN were investigated by feeding waste-activated sludge continuously and semicontinuously. The maximum percent reduction of both VSS and TN was achieved at a Q(r)/Q(s) ratio of 2 in the continuous process. The semicontinuous process was used to improve the nitrogen removal efficiency further. In the semicontinuous process, the VSS reduction efficiency as well as the nitrogen removal efficiency increased remarkably under a constant Q(r)/Q(s) ratio of 2. This process also achieved a VSS reduction efficiency higher than the aerobic digestion process (control). It was suggested that the additional anoxic tank enhanced the sludge digestion. Furthermore, the anoxic-aerobic digestion system can be applied to other treatment media like the primary sludge, industrial sludge, animal manure, etc.

Analysis of the combustion and pyrolysis of dried sewage sludge by TGA and MS.

PubMed

Magdziarz, Aneta; Werle, Sebastian

2014-01-01

In this study, the combustion and pyrolysis processes of three sewage sludge were investigated. The sewage sludge came from three wastewater treatment plants. Proximate and ultimate analyses were performed. The thermal behaviour of studied sewage sludge was investigated by thermogravimetric analysis with mass spectrometry (TGA-MS). The samples were heated from ambient temperature to 800 °C at a constant rate 10 °C/min in air (combustion process) and argon flows (pyrolysis process). The thermal profiles presented in form of TG/DTG curves were comparable for studied sludges. All TG/DTG curves were divided into three stages. The main decomposition of sewage sludge during the combustion process took place in the range 180-580 °C with c.a. 70% mass loss. The pyrolysis process occurred in lower temperature but with less mass loss. The evolved gaseous products (H2, CH4, CO2, H2O) from the decomposition of sewage sludge were identified on-line. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bacteriophages of wastewater foaming-associated filamentous Gordonia reduce host levels in raw activated sludge

PubMed Central

Liu, Mei; Gill, Jason J.; Young, Ry; Summer, Elizabeth J.

2015-01-01

Filamentous bacteria are a normal and necessary component of the activated sludge wastewater treatment process, but the overgrowth of filamentous bacteria results in foaming and bulking associated disruptions. Bacteriophages, or phages, were investigated for their potential to reduce the titer of foaming bacteria in a mixed-microbial activated sludge matrix. Foaming-associated filamentous bacteria were isolated from activated sludge of a commercial wastewater treatment plan and identified as Gordonia species by 16S rDNA sequencing. Four representative phages were isolated that target G. malaquae and two un-named Gordonia species isolates. Electron microscopy revealed the phages to be siphophages with long tails. Three of the phages - GordTnk2, Gmala1, and GordDuk1 - had very similar ~76 kb genomes, with >93% DNA identity. These genomes shared limited synteny with Rhodococcus equi phage ReqiDocB7 and Gordonia phage GTE7. In contrast, the genome of phage Gsput1 was smaller (43 kb) and was not similar enough to any known phage to be placed within an established phage type. Application of these four phages at MOIs of 5–15 significantly reduced Gordonia host levels in a wastewater sludge model by approximately 10-fold as compared to non-phage treated reactors. Phage control was observed for nine days after treatment. PMID:26349678

Evaluation of radiation hazard potential of TENORM waste from oil and natural gas production.

PubMed

Hilal, M A; Attallah, M F; Mohamed, Gehan Y; Fayez-Hassan, M

2014-10-01

In this study, a potential radiation hazard from TENORM sludge wastes generated during exploration and extraction processes of oil and gas was evaluated. The activity concentration of natural radionuclides (238)U, (226)Ra and (232)Th were determined in TENORM sludge waste. It was found that sludge waste from oil and gas industry is one of the major sources of (226)Ra in the environment. Therefore, some preliminary chemical treatment of sludge waste using Triton X-100 was also investigated to reduce the radioactivity content as well as the risk of radiation hazard from TENORM wastes. The activity concentrations of (226)Ra and (228)Ra in petroleum sludge materials before and after chemical treatment were measured using gamma-ray spectrometry. The average values of the activity concentrations of (226)Ra and (228)Ra measured in the original samples were found as 8908 Bq kg(-1) and 933 Bq kg(-1), respectively. After chemical treatment of TENORM samples, the average values of the activity concentrations of (226)Ra and (228)Ra measured in the samples were found as 7835 Bq kg(-1) and 574 Bq kg(-1), respectively. Activity concentration index, internal index, absorbed gamma dose rate and the corresponding effective dose rate were estimated for untreated and treated samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microbial adaptation to biodegrade toxic organic micro-pollutants in membrane bioreactor using different sludge sources.

PubMed

Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

2014-08-01

Biodegradation of toxic organic micro-pollutants in municipal solid waste (MSW) leachate by membrane bioreactor (MBR) was investigated. The MBR systems were seeded with different sludge sources, one was from a pilot-scale MBR system treating MSW leachate and the other was from an activated sludge sewage treatment plant. The biodegradation of BPA, 2,6-DTBP, BHT, DEP, DBP and DEHP, DCP and BBzP, by sludge from both reactors were found improved with time. However, enhanced biodegradation of micro-pollutants was observed in MBR operated under long sludge age condition. Bacterial population analyses determined by PCR-DGGE revealed the development of phenol and phthalate degrading bacteria consortium in MBR sludge during its operation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Response of wine grape growth, development and the transfer of copper, lead, and cadmium in soil-fruit system to sludge compost amendment.

PubMed

Liu, Hong-Tao; Wang, Yan-Wen; Huang, Wei-Dong; Lei, Mei

2016-12-01

Sludge is an organic waste after domestic sewage being treated and contains phytonutrients and organic matter. In this study, recycling of sludge compost (SC) and its compound fertilizer (SCF) to wine grape resulted in improvement in vegetative growth, reproductive development of wine grape, and potential wine quality of grape fruit. The amounts of Cu, Pb, and Cd in grape fruit were significantly higher in response to sludge amendment than in the control, but were all below the permissible limits for agricultural product. The contents of Cu and Pb in sludge-amended soil decreased with increasing soil depth, but Cd content increased with soil depth. Ongoing monitoring of on mobility of Cd downward is proposed with sludge recycling to wine grape soil.

Co-digestion of organic solid waste and sludge from sewage treatment.

PubMed

Edelmann, W; Engeli, H; Gradenecker, M

2000-01-01

Solid organic wastes were codigested together with sludge of a sewage treatment plant (STP). In the practical part of the study, a plant to pretreat the organic solid wastes provided by local super markets was constructed at the STP of Frutigen, Switzerland. Up to more than 1 cubic metre of wastes was added to the fermenter of the STP every day. Data collected during 14 months of practical works, showed that for raw fruit and vegetable wastes a two step pretreatment is necessary: First the wastes were chopped and afterwards reduced to a size of 1-2 millimetres, in order to get a homogeneous suspension together with the primary sludge. The vegetable wastes showed excellent digestibility: They seemed to accelerate the digestion process as well as to increase the degree of the anaerobic degradation of the sludge. The energy demand for both, pretreatment and digestion, was 85 kWh/ton of fresh wastes. 20% of the energy was used for the hygienization, a step which does not seem to be necessary for this kind of waste in most of the cases, however. After using the gas for energy conversion, a net yield of 65 kWh/ton of electricity and 166 kWh/ton of heat was measured. Treating cooked kitchen wastes, the net energy production will be higher, because in this case a one step pretreatment will be sufficient. The pretreatment and treatment costs for codigestion on STP's were calculated to be in the range of 55 US$/ton treating half a ton per day and 39 US$/ton treating one ton, respectively. A theoretical feasibility study showed that in Switzerland there is a short term potential on STP's for the codigestion of about 120,000 tons of biogenic wastes per year without big investments. Economic studies about codigestion on agricultural biogas plants showed that the codigestion is a must at the current energy prices, which are far too low for agricultural AD without an additional income by treating solid wastes for third parties.

EFFECT OF RECYCLING THERMOPHILICALLY DIGESTED SLUDGE ON THE ACTIVATED SLUDGE PROCESS

EPA Science Inventory

A full-scale investigation was undertaken at Chicago's Hanover Park Water Reclamation Plant (WRP) to study whether the net sludge production from the WRP could be reduced by implementing a scheme developed by W. Torpey et al. (1984). n this process, sludge is withdrawn from a the...

[Influence of accessories mixing ratio on sludge biophysical co-drying].

PubMed

Yang, Jin-Long; Du, Qiong; Li, Dong; Han, Rong; Zhao, Yan; Wang, Hong-Tao

2011-08-01

Parameters (temperature, water content and so on) in the process of sludge biophysical co-drying were studied in self-made biophysical co-drying reactor. The sludge: tree bark: recycled sludge was set as 7: 3: 0.5, 9: 3: 0.5, 12: 3: 0.5 respectively. The results suggested that sludge temperature first increased then decreased along with drying time, water content decreased in the first 96 h, then had no obvious variability. While sludge: tree bark: recycled sludge was 9: 3: 0.5, the temperature of sludge spiraling, received to max 67 degrees C at 48 h under three different accessories mixture ratio, and was kept for 72 h above 55 degrees C, then spiraling, the final water content of sludge decreased from 74.1% to 61.8%, received the optimal water content removing rate 43.5%. Accessories mixing ratio had important influence on the process of sludge biophysical co-drying, sludge with proper mixing ratio can modify the structure of sludge, improve sludge permeability, arouse and keep microorganic activity, which will enhance sludge temperature and strengthen water content removal rate.

Evaluation of a microwave based reactor for the treatment of blackwater sludge

PubMed Central

Mawioo, Peter M.; Rweyemamu, Audax; Garcia, Hector A.; Hooijmans, Christine M.; Brdjanovic, Damir

2016-01-01

A laboratory-scale microwave (MW) unit was applied to treat fresh blackwater sludge that represented fecal sludge (FS) produced at heavily used toilet facilities. The sludge was exposed to MW irradiation at different power levels and for various durations. Variables such as sludge volume and pathogen reduction were observed. The results demonstrated that the MW is a rapid and efficient technology that can reduce the sludge volume by over 70% in these experimental conditions. The concentration of bacterial pathogenic indicator E. coli also decreased to below the analytical detection levels. Furthermore, the results indicated that the MW operational conditions including radiation power and contact time can be varied to achieve the desired sludge volume and pathogen reduction. MW technology can be further explored for the potential scaling-up as an option for rapid treatment of FS from intensively used sanitation facilities such as in emergency situations. PMID:26799809

Modeling energy consumption in membrane bioreactors for wastewater treatment in north Africa.

PubMed

Skouterisl, George; Arnot, Tom C; Jraou, Mouna; Feki, Firas; Sayadi, Sami

2014-03-01

Two pilot-scale membrane bioreactors were operated alongside a full-sized activated sludge plant in Tunisia in order to compare specific energy demand and treated water quality. Energy consumption rates were measured for the complete membrane bioreactor systems and for their different components. Specific energy demand was measured for the systems and compared with the activated sludge plant, which operated at around 3 kWh m(-3). A model was developed for each membrane bioreactor based on both dynamic and steady-state mass balances, microbial kinetics and stoichiometry, and energy balance. Energy consumption was evaluated as a function of mixed-liquor suspended solids concentration, net permeate fluxes, and the resultant treated water quality. This work demonstrates the potential for using membrane bioreactors in decentralised domestic water treatment in North Africa, at energy consumption levels similar or lower than conventional activated sludge systems, with the added benefit of producing treated water suitable for unrestricted crop irrigation.

Anaerobic storage as a pretreatment for enhanced biodegradability of dewatered sewage sludge.

PubMed

Xu, Huacheng; He, Pinjing; Wang, Guanzhao; Shao, Liming; Lee, Duujong

2011-01-01

Dewatered sewage sludge is often stored still before further processing and final disposal. This study showed that anaerobic storage of dewatered sewage sludge could hydrolyze organic matter from the sludge matrix, and increase soluble organic acid content from 90 to 2400 mg/L and soluble organic carbon content from 220 to 1650 mg/L. Correspondingly, the contents of proteins, celluloses and hemicelluloses were reduced by 2-9%. Applying anaerobic storage markedly enhanced the efficiency of the subsequent bio-drying process on stored sludge. Correspondingly, biogas and odor gas were produced immediately after commencing the sludge storage. Anaerobic storage with odor control can be applied as a pretreatment process for dewatered sewage sludge in wastewater treatment plants. Copyright © 2010 Elsevier Ltd. All rights reserved.

The use of municipal sewage sludge for the stabilization of soil contaminated by mining activities.

PubMed

Theodoratos, P; Moirou, A; Xenidis, A; Paspaliaris, I

2000-10-02

The ability of municipal sewage sludge to immobilize Pb, Zn and Cd contained in contaminated soil originating from a former mining area in Lavrion, Greece was investigated. The soil was cured with sewage sludge in various proportions. The stabilization was evaluated primarily by applying chemical tests and complemented by the performance of additional biological tests. Application of the U.S. EPA Toxicity Characteristic Leaching Procedure (TCLP) on the stabilized mixtures proved that Pb, Zn and Cd solubility was reduced by 84%, 64% and 76%, respectively, at 15% w/w sludge addition, while a 10% w/w addition was sufficient to reduce Pb solubility below the U.S. EPA TCLP regulatory limit. The results of the extraction using EDTA solution showed the same trend, resulting in 26%, 36% and 53% reduction in the Pb, Zn and Cd extractable fractions, respectively. Speciation analysis of the treated soils revealed a significant decrease in the mobile fractions of heavy metals, which was attributed to their retention in sewage sludge by adsorption and organic complexation mechanisms. For the assessment of possible phytotoxicity, experiments including growing dwarf beans in the treated soil was carried out. It was found that sewage sludge addition had a positive effect on plant growth. Furthermore, the Pb and Zn uptake of plant leaves and roots was reduced, while Cd uptake was unaffected by the sludge treatment. The results of this study support the hypothesis that municipal sewage sludge is a potential effective stabilizing agent for contaminated soil containing Pb, Zn and Cd.

Influence of Continuous Flow Microwave Pre-Treatment on Anaerobic Digestion of Secondary Thickened Sludge for Sustainable Energy Recovery in Sewage Treatment Plant

NASA Astrophysics Data System (ADS)

Hephzibah, D.; Kumaran, P.; Saifuddin, N. M.

2016-03-01

This work elucidates the effects of pre-treatment of secondary thickened sludge (STS) for enhancement of biogas production that has great potential to generate energy for the utilization of the sewage treatment plant (STP) itself. Microwave pre-treatment has been adopted for this study. Experiment works have been designed and conducted to examine the effectiveness of continuous flow microwave pre-treatment on the solubility of STS, digestibility of STS and biogas production at a power level of 80 W for 5, 10 and 15 minutes. A few characteristics of the sewage sludge were monitored daily to identify the effect of pre-treatment on the sludge. The soluble chemical oxygen demand (SCOD)/total chemical oxygen demand (TCOD) ratio increased by 0.1, 1.0 and 1.8%, while the volatile fatty acids (VFA) concentration of the pre-treated sludge improved by 4.4, 5.1, 5.9% at the irradiation time of 5, 10 and 15 minutes, respectively at a microwave power level of 80 W. Besides that, the digestate also indicates that the pre-treated sludge undergoes efficient VS removal and TCOD removal after anaerobic digestion compared to the untreated sludge. Moreover, the biogas quantity increased by an average of 19.2, 24.1 and 32.2% in 5, 10 and 15 minutes irradiation time respectively compared to the untreated sludge. The additional quantity of biogas generated has shown a great potential for sustainable energy generation that can be utilized internally by the STP.

Chromium fractionation and plant availability in tannery-sludge amended soil

NASA Astrophysics Data System (ADS)

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

2013-04-01

The leather industry represents an important economic sector in both developed and developing countries. Chromium tanning is the major process used to obtain high quality leather. Within the REACH regulation the use of Cr, especially CrVI, in the tanning process is under discussion in Europe. High Cr concentration in shoes and other Cr-tanned leather products can cause contact dermatitis in sensitive population. Moreover, the high Cr concentration is the major limiting factor for the use of tannery sludge as a source of organic matter in agricultural soils. Interest in Cr, however is not limited to its potential toxic effects. Chromium III is used as a dietary supplement because there are reports, but also controversy, about the positive effects of Cr III in glucose tolerance and type-2 diabetes. Adequate intake levels for Cr by the diet have been established between 25 and 35 µg/day for adult females and males, respectively. Sufficient supply of Cr III by the diet is preferable to the use of CrIII-salt based dietary supplements. The objective of the present work was to investigate whether Cr from tannery sludge-amended soil is available to Trigonella foenum-graecum plants, a plant used both as a spice and as a medicinal herb, because of its hypoglucemic effects. For this purpose clay loam soil (pH 7.8) was sieved (2mm) and thoroughly mixed with tannery sludge from a depuration station (Igualadina Depuració i Recuperació S.L., Igualada, Barcelona, Spain). The sludge had a Cr concentration of 6,034mg kg-1 and a 0.73 % of NH4-nitrogen. All the Cr was in the form of CrIII. Three treatments were disposed. Control soil receiving no sludge, a 60 mg kg-1 Cr treatment (10 g fresh sludge kg-1 soil) and a 120 mg kg-1 Cr treatment (20 g fresh sludge kg-1 soil). Control soil and the soil treated with 10g kg-1 sludge received NPK fertilizer in the form of ammonium sulfate, superfosfate, and KCl to rise the N,P, and K concentrations to similar levels to those achieved in the soils with the highest sludge dose (20 g kg-1). Soils from the different treatments were potted (5 L) and planted with Trigonella foenum graecum seeds (1 plant per pot). Plants were harvested in the vegetative stage and processed for tissue analysis of Cr, Fe, Zn and Pb. A sequential extraction procedure was applied to the soil for getting insight into the operationally defined soil fractions that incorporate the tannery sludge derived Cr. In any of the treatments Cr was detectable in the exchangeable and easily reducible fractions. In control soils around 10% of soil Cr was in the moderately reducible fraction and the rest in the residual fraction. Contrastingly tannery sludge amended soils incorporated most Cr in the moderately reducible fraction extracted by acid oxalate. This distribution in relation to plant Cr concentrations will be discussed. Acknowledgement: Supported by the Spanish Government (project BFU2010-14873)

In situ remediation process using divalent metal cations

DOEpatents

Brady, Patrick V.; Khandaker, Nadim R.; Krumhansl, James L.; Teter, David M.

2004-12-14

An in situ process for treating ambient solid materials (e.g., soils, aquifer solids, sludges) by adding one or more divalent metal cations to the ambient solid material. The added divalent metal cations, such as Cu.sup.2+ or Zn.sup.2+, combine with metal oxide/hydroxides (e.g., ferric oxide/hydroxide or aluminum oxide/hydroxide) already present in the ambient solid material to form an effective sorbent material having a large number of positively-charged surface complexes that binds and immobilizes anionic contaminant species (e.g., arsenic or chromate). Divalent metal cations can be added, for example, by injecting an aqueous solution of CuSO.sub.4 into an aquifer contaminated with arsenic or chromate. Also, sludges can be stabilized against leaching of anionic contaminants through the addition of divalent metal cations. Also, an inexpensive sorbent material can be easily formed by mixing divalent metal cations with soil that has been removed from the ground.

Treatment of real wastewater produced from Mobil car wash station using electrocoagulation technique.

PubMed

El-Ashtoukhy, E-S Z; Amin, N K; Fouad, Y O

2015-10-01

This paper deals with the electrocoagulation of real wastewater produced from a car wash station using a new cell design featuring a horizontal spiral anode placed above a horizontal disc cathode. The study dealt with the chemical oxygen demand (COD) reduction and turbidity removal using electrodes in a batch mode. Various operating parameters such as current density, initial pH, NaCl concentration, temperature, and electrode material were examined to optimize the performance of the process. Also, characterization of sludge formed during electrocoagulation was carried out. The results indicated that the COD reduction and turbidity removal increase with increasing the current density and NaCl concentration; pH from 7 to 8 was found to be optimum for treating the wastewater. Temperature was found to have an insignificant effect on the process. Aluminum was superior to iron as a sacrificial electrode material in treating car wash wastewater. Energy consumption based on COD reduction ranged from 2.32 to 15.1 kWh/kg COD removed depending on the operating conditions. Finally, the sludge produced during electrocoagulation using aluminum electrodes was characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analysis.

Survival rates of parasite eggs in sludge during aerobic and anaerobic digestion.

PubMed Central

Black, M I; Scarpino, P V; O'Donnell, C J; Meyer, K B; Jones, J V; Kaneshiro, E S

1982-01-01

The effects of mesothermic anaerobic or aerobic sludge digestion on survival of eggs from the roundworms Ascaris suum, toxocara canis, Trichuris vulpis, and Trichuris suis and from the rat tapeworm Hymenolepis diminuta were studied. Destruction of eggs throughout a 15-day treatment period, as well as their viabilities after reisolation, was analyzed. The laboratory model digesters used in this study were maintained at a 15-day retention schedule, partially simulating a continuously operating system. Ascaris eggs were destroyed in the anaerobic (23%) or aerobic (38%) digesters, and 11% Trichuris eggs were destroyed in the aerobic digesters. Trichuris eggs in anaerobic digesters and Toxocara eggs in either anaerobic or aerobic digesters were not destroyed. Destruction of eggs in digesters was correlated with the state of the eggs before subjection to the treatment processes; i.e., some Ascaris and Trichuris eggs were already embryonated in host intestinal contents or feces and hence past their most resistant stage. The viabilities of Ascaris and Toxocara eggs that survived the digestion processes were greater in anaerobically treated than in aerobically treated material. Eggs from Hymenolepis were nonviable before use in the experiments. However, they were more effectively destroyed in aerobic digesters than in anaerobic digesters. PMID:6891199

Methods for Converter Sludge Dehydration Intensification

NASA Astrophysics Data System (ADS)

Vakhromeev, M. I.; Moreva, Y. A.; Starkova, L. G.

2017-11-01

The article considers the intensification methods for converter sludge dehydration exemplified by the sludges of the Oxygen Converter Workshop (OCW) of the Open Joint-Stock Company “Magnitogorsk Iron and Steel Works” (MMK, OJSC), one of the largest metallurgical companies in the Southern Urals. Converter sludges can contain up to 45-70% of ferrum [21] which is interesting in terms of their use as an addition to a sinter-feed mixture. Sludge intensifies the sintering process. It positively influences pelletizing and fusion mixture melting dynamics at sintering. Over the period of the converter sludge dehydration complex operation at the OCW, MMK, OJSC, it was revealed that processing results in obtaining of high humidity sludge. It causes sludge freezing during the winter period, thus, its transportation involves extra costs for sludge warming up. To resolve the above-mentioned problem, the following works were performed in 2016: - experimental studies of how the application of the low-molecular anionic flocculate “SEURVEY” FL-3 influences sludge humidity reduction. - experimental studies of how the filtering press process operation parameters influence sludge humidity reduction. The new flocculate application didn't lower the dehydrated sludge humidity (the objective was the humidity of not more than 15%). Basing upon the conducted research results, we can make a conclusion that putting into operation the sewage water reactant treatment technology with the use of “SEURVEY”, FL-3 (H-10) is not recommended. The research of the influence the filtering press process parameters have on the dehydration process intensification demonstrated that reaching of the obtained residue humidity value lower than 15% is possible under the reduction of the filtering press chamber depths to 30 mm and with the application of additional operation “Residue drying” with compressed air. This way of the sludge dehydration problem resolving at filtering presses of the converter sludge dehydration complex of the OCW, MMK, OJSC, can be recommended for application.

Overall effect of carbon production and nutrient release in sludge holding tank on mainstream biological nutrient removal efficiency.

PubMed

Jabari, Pouria; Yuan, Qiuyan; Oleszkiewicz, Jan A

2017-09-11

The potential of hydrolysis/fermentation of activated sludge in sludge holding tank (SHT) to produce additional carbon for the biological nutrient removal (BNR) process was investigated. The study was conducted in anaerobic batch tests using the BNR sludge (from a full-scale Westside process) and the mixture of BNR sludge with conventional non-BNR activated sludge (to have higher biodegradable particulate chemical oxygen demand (bpCOD) in sludge). The BioWin 4.1 was used to simulate the anaerobic batch test of the BNR sludge. Also, the overall effect of FCOD production and nutrient release on BNR efficiency of the Westside process was estimated. The experimental results showed that the phosphorous uptake of sludge increased during hydrolysis/ fermentation condition up to the point when poly-P was completely utilized; afterwards, it decreased significantly. The BioWin simulation could not predict the loss of aerobic phosphorous uptake after poly-P was depleted. The results showed that in the case of activated sludge with relatively higher bpCOD (originating from plants with short sludge retention time or without primary sedimentation), beneficial effect of SHT on BNR performance is feasible. In order to increase the potential of SHT to enhance BNR efficiency, a relatively low retention time and high sludge load is recommended.

Investigating the performance of three modified activated sludge processes treating municipal wastewater in organic pollutants removal and toxicity reduction.

PubMed

Han, Xue; Zuo, Yu-Ting; Hu, Yu; Zhang, Jie; Zhou, Meng-Xuan; Chen, Mo; Tang, Fei; Lu, Wen-Qing; Liu, Ai-Lin

2018-02-01

This study investigated the treatment performance of three types of modified activated sludge processes, i.e., anoxic/oxic (A/O), anaerobic/anoxic/oxic (A2/O) and oxidation ditch process, in treating municipal wastewater by measuring physicochemical and spectroscopic parameters, and the toxicity of the influents and effluents collected from 8 full-scale municipal wastewater treatment plants (MWTPs). The relationships between spectroscopic and physicochemical parameters of the wastewater samples and the applicability of the nematode Caenorhabditis elegans (C. elegans) bioassays for the assessment of the toxic properties of municipal wastewater were also evaluated. The results indicated that the investigated MWTPs employing any of A/O, A2/O and oxidation ditch processes could effectively control the discharge of major wastewater pollutants including biochemical oxygen demand (BOD), chemical oxygen demand, nitrogen and phosphorus. The oxidation ditch process appeared to have the advantage of removing tyrosine-like substances and presented slightly better removal efficiency of tryptophan-like fluorescent (peak T) substances than the A/O and A2/O processes. Both ultraviolet absorbance at 254nm and peak T may be used to characterize the organic load of municipal wastewater, and peak T can be adopted as a gauge of the BOD removal efficacy of municipal wastewater treatment. Using C. elegans-based oxygen consumption rate assay for monitoring municipal wastewater toxicity deserves further investigations. Copyright © 2017 Elsevier Inc. All rights reserved.

The color removal and fate of organic pollutants in a pilot-scale MBR-NF combined process treating textile wastewater with high water recovery.

PubMed

Li, Kun; Jiang, Chao; Wang, Jianxing; Wei, Yuansong

2016-01-01

A combination of membrane bioreactor (MBR) and nanofiltration (NF) was tested at pilot-scale treating textile wastewater from the wastewater treatment station of a textile mill in Wuqing District of Tianjin (China). The MBR-NF process showed a much better treatment efficiency on the removal of the chemical oxygen demand, total organic carbon, color and turbidity in comparison with the conventional processes. The water recovery rate was enhanced to over 90% through the recycling of NF concentrate to the MBR, while the MBR-NF showed a stable permeate water quality that met with standards and could be directly discharged or further reused. The recycled NF concentrate caused an accumulation of refractory compounds in the MBR, which significantly influenced the treatment efficiency of the MBR. However, the sludge characteristics showed that the activated sludge activity was not obviously inhibited. The results of fluorescence spectra and molecular weight distribution indicated that those recalcitrant pollutants were mostly protein-like substances and a small amount of humic acid-like substances (650-6,000 Da), which contributed to membrane fouling of NF. Although the penetrated protein-like substances caused the residual color in NF permeate, the MBR-NF process was suitable for the advanced treatment and reclamation of textile wastewater under high water yield.

Archaeal community dynamics and abiotic characteristics in a mesophilic anaerobic co-digestion process treating fruit and vegetable processing waste sludge with chopped fresh artichoke waste.

PubMed

Ros, M; Franke-Whittle, I H; Morales, A B; Insam, H; Ayuso, M; Pascual, J A

2013-05-01

This study evaluated the feasibility of obtaining methane in anaerobic digestion (AD) from the waste products generated by the processing of fruit and vegetables. During the first phase (0-55 d) of the AD using sludge from fruit and vegetable processing, an average value of 244±88 L kg(-1) dry matter d(-1)of biogas production was obtained, and methane content reached 65% of the biogas. Co-digestion with chopped fresh artichoke wastes in a second phase (55-71 d) enhanced biogas production, and resulted in an average value of 354±68 L kg(-1) dry matter d(-1), with higher methane content (more than 70%). The archaeal community involved in methane production was studied using the ANAEROCHIP microarray and real-time PCR. Results indicated that species of Methanosaeta and Methanosarcina were important during the AD process. Methanosarcina numbers increased after the addition of chopped fresh artichoke, while Methanosaeta numbers decreased. Copyright © 2013 Elsevier Ltd. All rights reserved.

A combined upflow anaerobic sludge bed and trickling biofilter process for the treatment of swine wastewater.

PubMed

Zhao, Bowei; Li, Jiangzheng; Buelna, Gerardo; Dubé, Rino; Le Bihan, Yann

2016-01-01

A combined upflow anaerobic sludge blanket (UASB)-trickling biofilter (TBF) process was constructed to treat swine wastewater, a typical high-strength organic wastewater with low carbon/nitrogen ratio and ammonia toxicity. The results showed that the UASB-TBF system can remarkably enhance the removal of pollutants in the swine wastewater. At an organic loading rate of 2.29 kg/m(3) d and hydraulic retention time of 48 h in the UASB, the chemical oxygen demand (COD), Suspended Solids and Total Kjeldahl Nitrogen removals of the combined process reached 83.6%, 84.1% and 41.2%, respectively. In the combined system the UASB served as a pretreatment process for COD removal while nitrification and denitrification occurred only in the TBF process. The TBF performed reasonably well at a surface hydraulic load as high as 0.12 m(3)/m(2) d. Since the ratio of influent COD to total mineral nitrogen was less than 3.23, it is reasonable to suggest that the wood chips in TBF can serve as a new carbon source for denitrification.

Achieve efficient nitrogen removal from real sewage in a plug-flow integrated fixed-film activated sludge (IFAS) reactor via partial nitritation/anammox pathway.

PubMed

Yang, Yandong; Zhang, Liang; Cheng, Jun; Zhang, Shujun; Li, Baikun; Peng, Yongzhen

2017-09-01

This study tested the feasibility of plug-flow integrated fixed-film activated sludge (IFAS) reactor in applying sewage partial nitritation/anammox (PN/A) process. The IFAS reactor was fed with real pre-treated sewage (C/N ratio=1.3) and operated for 200days. High nitrogen removal efficiency of 82% was achieved with nitrogen removal rates of 0.097±0.019kgN/(m 3 ·d). Therefore, plug-flow IFAS reactor could be an alternative to applying sewage PN/A process. Besides, it was found that the stability of sewage PN/A process was significantly affected by residual ammonium. Nitrate accumulated in effluent and PN/A performance deteriorated when residual ammonium was below 1mg/L. On the contrary, long-term stable PN/A operation was achieved when residual ammonium was over 3mg/L. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mesophilic and thermophilic anaerobic co-digestion of winery wastewater sludge and wine lees: An integrated approach for sustainable wine production.

PubMed

Da Ros, C; Cavinato, C; Pavan, P; Bolzonella, D

2017-12-01

In this work, winery wastes generated by a cellar producing approximately 300,000 hL of wine per year was monitored for a period of one year. On average, 196 L of wastewater, 0.1 kg of waste activated sludge (dry matter) and 1.6 kg of wine lees were produced per hectoliter of wine produced. Different winery wastes, deriving from different production steps, namely waste activated sludge from wastewater treatment and wine lees, were co-treated using an anaerobic digestion process. Testing was conducted on a pilot scale for both mesophilic and thermophilic conditions. The process was stable for a long period at 37 °C, with an average biogas production of 0.386 m 3 /kg COD fed . On the other hand, for thermophilic conditions, volatile fatty acids accumulated in the reactor and the process failed after one hydraulic retention time (23 days). In order to fix the biological process, trace elements (iron, cobalt and nickel) were added to the feed of the thermophilic reactor. Metals augmentation improved process stability and yields at 55 °C. The pH ranged between 7.8 and 8.0, and specific gas production was 0.450 m 3 /kg COD fed , which corresponded to dry matter and COD removals of 34% and 88%, respectively. Although the observed performances in terms of biogas production were good, the thermophilic process exhibited some limitations related to both the necessity of metals addition and the worse dewaterability properties. In fact, while the mesophilic digestates reached a good dewatering quality via the addition of 6.5 g of polymer per kg of dry matter, the required dosage for the thermophilic sludge was greater than 10 g/kg of dry matter. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of advanced oxidation processes on the micropollutants and the effluent organic matter contained in municipal wastewater previously treated by three different secondary methods.

PubMed

Giannakis, Stefanos; Gamarra Vives, Franco Alejandro; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

2015-11-01

In this study, wastewater from the output of three different secondary treatment facilities (Activated Sludge, Moving Bed Bioreactor and Coagulation-Flocculation) present in the municipal wastewater treatment plant of Vidy, Lausanne (Switzerland), was further treated with various oxidation processes (UV, UV/H2O2, solar irradiation, Fenton, solar photo-Fenton), at laboratory scale. For this assessment, 6 organic micropollutants in agreement with the new environmental legislation requirements in Switzerland were selected (Carbamazepine, Clarithromycin, Diclofenac, Metoprolol, Benzotriazole, Mecoprop) and monitored throughout the treatment. Also, the overall removal of the organic load was assessed. After each secondary treatment, the efficiency of the AOPs increased in the following order: Coagulation-Flocculation < Activated Sludge < Moving Bed Bioreactor, in almost all cases. From the different combinations tested, municipal wastewater subjected to biological treatment followed by UV/H2O2 resulted in the highest elimination levels. Wastewater previously treated by physicochemical treatment demonstrated considerably inhibited micropollutant degradation rates. The degradation kinetics were determined, yielding: k (UV) < k (UV/H2O2) and k (Fenton) < k (solar irradiation) < k (photo-Fenton). Finally, the evolution of global pollution parameters (COD & TOC elimination) was followed and the degradation pathways for the effluent organic matter are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions.

PubMed

Lv, Dong; Zhu, Tianle; Liu, Runwei; Lv, Qingzhi; Sun, Ye; Wang, Hongmei; Liu, Yu; Zhang, Fan

2016-09-01

The effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions were systematically investigated in a cement production line in Beijing. The results show that co-processing the sewage sludge was helpful to reduce NOx emission, which primarily depends on the NH3 amount released from the sewage sludge. Meanwhile, NOx and NH3 concentrations in the flue gas have a negative correlation, and the contribution of feeding the sewage sludge to NOx removal decreased with the increase of injection amount of ammonia water in the SNCR system. Therefore, it is suggested that the injection amount of ammonia water in SNCR system may reduce to cut down the operating costs during co-processing the sewage sludge in cement kiln. In addition, the emission of total PAHs seems to increase with the increased amount of the sewage sludge feeding to the cement kiln. However, the distributions of PAHs were barely changed, and lower molecular weight PAHs were mainly distributed in gaseous phase, accounted for the major portion of PAHs when co-processing sewage sludge in cement kiln. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced dewaterability of textile dyeing sludge using micro-electrolysis pretreatment.

PubMed

Ning, Xun-An; Wen, Weibin; Zhang, Yaping; Li, Ruijing; Sun, Jian; Wang, Yujie; Yang, Zuoyi; Liu, Jingyong

2015-09-15

The effects of micro-electrolysis treatment on textile dyeing sludge dewatering and its mechanisms were investigated in this study. Capillary suction time (CST) and settling velocity (SV) were used to evaluate sludge dewaterability. Extracellular polymeric substances (EPS) concentration and sludge disintegration degree (DDSCOD) were determined to explain the observed changes in sludge dewaterability. The results demonstrated that the micro-electrolysis could significantly improve sludge dewaterability by disrupting the sludge floc structure. The optimal conditions of sludge dewatering were the reaction time of 20 min, initial pH of 2.5, Fe/C mass ratio of 1/1, and the iron powder dosage of 2.50 g/L, which achieved good CST (from 34.1 to 27.8 s) and SV (from 75 to 60%) reduction efficiency. In addition, the scanning electron microscope (SEM) images revealed that the treated sludge floc clusters are broken up and that the dispersion degree is better than that of a raw sludge sample. The optimal EPS concentration and DDSCOD to obtain maximum sludge dewaterability was 43-46 mg/L and 4.2-4.9%, respectively. The destruction of EPS was one of the primary reasons for the improvement of sludge dewaterability during micro-electrolysis treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioaccumulation of metals in ryegrass (Lolium perenne L.) following the application of lime stabilised, thermally dried and anaerobically digested sewage sludge.

PubMed

Healy, M G; Ryan, P C; Fenton, O; Peyton, D P; Wall, D P; Morrison, L

2016-08-01

The uptake and accumulation of metals in plants is a potential pathway for the transfer of environmental contaminants in the food chain, and poses potential health and environmental risks. In light of increased population growth and urbanisation, the safe disposal of sewage sludge, which can contain significant levels of toxic contaminants, remains an environmental challenge globally. The aims of this experiment were to apply municipal sludge, having undergone treatment by thermal drying, anaerobic digestion, and lime stabilisation, to permanent grassland in order to assess the bioaccumulation of metals (B, Al, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Nb, Mo, Sb, Ba, W, Pb, Fe, Cd) by perennial ryegrass over a period of up to 18 weeks after application. The legislation currently prohibits use of grassland for fodder or grazing for at least three weeks after application of treated sewage sludge (biosolids). Five treatments were used: thermally dried (TD), anaerobically digested (AD) and lime stabilised (LS) sludge all from one wastewater treatment plant (WWTP), AD sludge from another WWTP, and a study control (grassland only, without application of biosolids). In general, there was no significant difference in metal content of the ryegrass between micro-plots that received treated municipal sludge and the control over the study duration. The metal content of the ryegrass was below the levels at which phytotoxicity occurs and below the maximum levels specified for animal feeds. Copyright © 2016 Elsevier Inc. All rights reserved.

Migration and transformation of sulfur in the municipal sewage sludge during disposal in cement kiln.

PubMed

Huang, Yuyan; Li, Haoxin; Jiang, Zhengwu; Yang, Xiaojie; Chen, Qing

2018-05-07

The aim of this work was to investigate the migration and transformation of sulfur in the municipal sewage sludge during disposal in cement kiln, and better understand the emission of the sulfur related pollutants in this process. In consideration of the temperature conditions in the practical operation, municipal sewage sludge was pre-dried at 105 °C, and then dried at 210, 260 and 310 °C, co-combusted with cement raw mill at 800, 900 and 1000 °C, and 1350, 1400 and 1450 °C respectively in the laboratory. X-ray photoelectron spectroscopy (XPS) was used to determine the S2p spectral lines of the municipal sewage sludge treated in the different process. Besides, The Thermal Analysis-Thermogravimetry (DTA-TG), Back Scattered Electron (BSE) and Energy Dispersive Spectrometer (EDS) were also employed to explore the mechanism of sulfur subsistence at 1450 °C. The results indicate that sulfide, thiophene, sulfone and sulfate are mainly sulfur compound in the municipal sewage sludge dried at 105 °C. Sulfoxide, a new sulfur compound, appears after it is further dried at 210 °C. The relative contents of sulfide and thiophene are continuously declined as the drying temperature increases due to their evaporation, decomposition and transformation in this process. The transformation of sulfide and thiophene makes the relative contents of sulfoxide and sulfate accordingly increased. However, the relative content of sulfone experiences an elevating-lowering process while the dry temperature elevated from 210 to 310 °C. This case is related to its evaporation and decomposition, as well as its production for the transformation of sulfide and thiophene. In the co-combustion process, sulfide, thiophene and sulfone are entirely vanished for their evaporation, decomposition and transformation. Sulfone is still contained at 800 °C, but when the temperature unceasingly rises, it is completely decomposed or evaporated and sulfate is the only sulfur compound. The microstructures left by the gas release are also observed in the mixtures sintered at 1450 °C, however sulfate still exists even at 1450 °C. The BSE and EDS results show that the melt phase is the important contribution to the appearance of sulfate at the high temperature. These results will sever as a theoretically reference for the pollution control of the sulfur related pollutants in the disposal process of the municipal sewage sludge in cement kiln. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improving material and energy recovery from the sewage sludge and biomass residues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kliopova, Irina, E-mail: irina.kliopova@ktu.lt; Makarskienė, Kristina

2015-02-15

Highlights: • SRF production from 10–40 mm fraction of pre-composted sludge and biomass residues. • The material and energy balance of compost and SRF production. • Characteristics of raw materials and classification of produced SRF. • Results of the efficiency of energy recovery, comparison analysis with – sawdust. - Abstract: Sewage sludge management is a big problem all over the world because of its large quantities and harmful impact on the environment. Energy conversion through fermentation, compost production from treated sludge for agriculture, especially for growing energetic plants, and treated sludge use for soil remediation are widely used alternatives ofmore » sewage sludge management. Recently, in many EU countries the popularity of these methods has decreased due to the sewage sludge content (heavy metals, organic pollutions and other hazards materials). This paper presents research results where the possibility of solid recovered fuel (SRF) production from the separate fraction (10–40 mm) of pre-composted materials – sewage sludge from municipal waste water treatment plant and biomass residues has been evaluated. The remaining fractions of pre-composted materials can be successfully used for compost or fertiliser production, as the concentration of heavy metals in the analysed composition is reduced in comparison with sewage sludge. During the experiment presented in this paper the volume of analysed biodegradable waste was reduced by 96%: about 20% of input biodegradable waste was recovered to SRF in the form of pellets with 14.25 MJ kg{sup −1} of the net calorific value, about 23% were composted, the rest – evaporated and discharged in a wastewater. The methods of material-energy balances and comparison analysis of experiment data have been chosen for the environmental impact assessment of this biodegradable waste management alternative. Results of the efficiency of energy recovery from sewage sludge by SRF production and burning, comparison analysis with widely used bio-fuel–sawdust and conclusions made are presented.« less

HELMINTH OVA AND VIRUS DETECTION IN BIOSOLIDS

EPA Science Inventory

Sewage sludge (also known as biosolids), a byproduct from domestic sewage treatment, is often used as an organic soil conditioner and fertilizer. Raw sludge must be treated to reduce levels of potential human pathogenic agents before being used for this purpose. The domestic us...

Monitoring the fate and behavior of TiO2 nanoparticles: Simulated in a WWTP with industrial dye-stuff effluent according to OECD 303A.

PubMed

Mahlalela, Lwazi C; Ngila, Jane C; Dlamini, Langelihle N

2017-07-03

The use of nanoparticles (NPs) in several consumer products has led to them finding their way into wastewater treatment plants (WWTPs). Some of these NPs have photocatalytic properties, thus providing a possible solution to textile industries to photodegrade dyes from their wastewater. Thus, the interaction of NPs with industrial dye effluents is inevitable. The Organization for Economic Co-operation and development (OECD) guideline for testing of chemical 303A was employed to study the fate and behaviour of TiO 2 NPs in industrial dye-stuff effluent. This was due to the unavailability of NPs' fate and behaviour test protocols. The effect of TiO 2 NPs on the treatment process was ascertained by measuring chemical oxygen demand (COD) and 5-day biological oxygen demand (BOD5). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to study the fate and behavior of TiO 2 NPs. Acclimatization of bacteria to target pollutants was a crucial factor for the treatment efficiency of activated sludge in a simulated wastewater treatment plant (SWTP). The acclimatization of the activated sludge to the synthetic industrial dye-stuff effluent was successfully achieved. Effect of TiO 2 NPs on the treatment process efficiency was then investigated. Addition of TiO 2 NPs had no effect on the treatment process as chemical oxygen demand (COD) removal remained >80%. Measured total plate count (TPC) affirmed that the addition of TiO 2 NPs had no effect on the treatment process. The removal of total nitrogen (TN) was not efficient as the treatment system was required to have an oxic and anoxic stage for efficient TN removal. Results from X-ray powder diffraction (XRD) confirmed that the anatase phase of the added TiO 2 NPs remained unchanged even after exposure to the treatment plant. Removal of the NPs from the influent was facilitated by biosorption of the NPs on the activated sludge. Nanoparticles received by wastewater treatment plants will therefore reach the environment through sludge waste dumped in landfill. About 90% of TiO 2 was retained in the activated sludge, and 10-11% escaped with the treated effluents. Scanning electron microscope (SEM) mapping micrographs together with an energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Ti in the sludge.

Biotransformation of arsenic species by activated sludge and removal of bio-oxidised arsenate from wastewater by coagulation with ferric chloride.

PubMed

Andrianisa, Harinaivo Anderson; Ito, Ayumi; Sasaki, Atsushi; Aizawa, Jiro; Umita, Teruyuki

2008-12-01

The potential of activated sludge to catalyse bio-oxidation of arsenite [As(III)] to arsenate [As(V)] and bio-reduction of As(V) to As(III) was investigated. In batch experiments (pH 7, 25 degrees C) using activated sludge taken from a treatment plant receiving municipal wastewater non-contaminated with As, As(III) and As(V) were rapidly biotransformed to As(V) under aerobic condition and As(III) under anaerobic one without acclimatisation, respectively. Sub-culture of the activated sludge using a minimal liquid medium containing 100mg As(III)/L and no organic carbon source showed that aerobic arsenic-resistant bacteria were present in the activated sludge and one of the isolated bacteria was able to chemoautotrophically oxidise As(III) to As(V). Analysis of arsenic species in a full-scale oxidation ditch plant receiving As-contaminated wastewater revealed that both As(III) and As(V) were present in the influent, As(III) was almost completely oxidised to As(V) after supply of oxygen by the aerator in the oxidation ditch, As(V) oxidised was reduced to As(III) in the anaerobic zone in the ditch and in the return sludge pipe, and As(V) was the dominant species in the effluent. Furthermore, co-precipitation of As(V) bio-oxidised by activated sludge in the plant with ferric hydroxide was assessed by jar tests. It was shown that the addition of ferric chloride to mixed liquor as well as effluent achieved high removal efficiencies (>95%) of As and could decrease the residual total As concentrations in the supernatant from about 200 microg/L to less than 5 microg/L. It was concluded that a treatment process combining bio-oxidation with activated sludge and coagulation with ferric chloride could be applied as an alternative technology to treat As-contaminated wastewater.

Transformation of heavy metal speciation during sludge drying: mechanistic insights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weng, Huanxin; Ma, Xue-Wen; Fu, Feng-Xia

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized the Cr, Cu, Cd and Pb in sludge by transforming acid-soluble, reducible andmore » oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge.« less

The influence of SRT on phosphorus removal and sludge characteristics in the HA-A/A-MCO sludge reduction process

NASA Astrophysics Data System (ADS)

Zuo, N.; Ji, F. Y.

2013-02-01

By researching the influence of sludge age (SRT) on phosphorous removal and sludge characteristics in the HA-A/A-MCO (hydrolysis-acidification-anaerobic/anoxic-multistep continuous oxic tank) process, which has the effect of simultaneous phosphorous and nitrogen removal and sludge reduction, it is found that extended SRT is helpful for improving the ability of anaerobic phosphorous release and chemical recovery of phosphate, but the hosphorous removal efficiency is not affected. Extended SRT causes the system to have even more active sludge; it can also lead to the system having a powerful ability of biochemical reaction by using superiority of concentration. Meanwhile, extended SRT can still reduce sludge yield. Extended SRT cannot make soluble metabolic product (SMP) accumulate in the reactor, so that the pollutant removal power is reduced; it also cannot affect the activity of the sludge. However, extended SRT is able to make the coagulation of the sludge hard, and cause the sludge volume index value increase, but cannot cause sludge bulking.

The effect of bioleaching on sewage sludge pyrolysis.

PubMed

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.

Microbial community related to lysozyme digestion process for boosting waste activated sludge biodegradability.

PubMed

Xin, Xiao-Dong; He, Jun-Guo; Qiu, Wei; Tang, Jian; Liu, Tian-Tian

2015-01-01

Waste activated sludge from a lab-scale sequencing batch reactor was used to investigate the potential relation of microbial community with lysozyme digestion process for sludge solubilization. The results showed the microbial community shifted conspicuously as sludge suffered lysozyme digestion. Soluble protein and polysaccharide kept an increasing trend in solution followed with succession of microbial community. The rise of lysozyme dosage augmented the dissimilarity among communities in various digested sludge. A negative relationship presented between community diversity and lysozyme digestion process under various lysozyme/TS from 0 to 240min (correlation coefficient R(2) exceeded 0.9). Pareto-Lorenz curves demonstrated that microbial community tended to be even with sludge disintegration process by lysozyme. Finally, with diversity (H) decrease and community distribution getting even, the SCOD/TCOD increased steadily in solution which suggested the sludge with high community diversity and uneven population distribution might have tremendous potential for improving their biodegradability by lysozyme digestion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantification of hookworm ova from wastewater matrices using quantitative PCR.

PubMed

Gyawali, Pradip; Ahmed, Warish; Sidhu, Jatinder P; Jagals, Paul; Toze, Simon

2017-07-01

A quantitative PCR (qPCR) assay was used to quantify Ancylostoma caninum ova in wastewater and sludge samples. We estimated the average gene copy numbers for a single ovum using a mixed population of ova. The average gene copy numbers derived from the mixed population were used to estimate numbers of hookworm ova in A. caninum seeded and unseeded wastewater and sludge samples. The newly developed qPCR assay estimated an average of 3.7×10 3 gene copies per ovum, which was then validated by seeding known numbers of hookworm ova into treated wastewater. The qPCR estimated an average of (1.1±0.1), (8.6±2.9) and (67.3±10.4) ova for treated wastewater that was seeded with (1±0), (10±2) and (100±21) ova, respectively. The further application of the qPCR assay for the quantification of A. caninum ova was determined by seeding a known numbers of ova into the wastewater matrices. The qPCR results indicated that 50%, 90% and 67% of treated wastewater (1L), raw wastewater (1L) and sludge (~4g) samples had variable numbers of A. caninum gene copies. After conversion of the qPCR estimated gene copy numbers to ova for treated wastewater, raw wastewater, and sludge samples, had an average of 0.02, 1.24 and 67 ova, respectively. The result of this study indicated that qPCR can be used for the quantification of hookworm ova from wastewater and sludge samples; however, caution is advised in interpreting qPCR generated data for health risk assessment. Copyright © 2017. Published by Elsevier B.V.

Effects of stabilization and sludge properties in a combined process of anaerobic digestion and thermophilic aerobic digestion.

PubMed

Cheng, Jiehong; Kong, Feng; Zhu, Jun; Wu, Xiao

2015-01-01

A novel process of combining mesophilic (<35°C) anaerobic digestion with the thermophilic (55°C) aerobic digestion process (AN-TAD) was designed to stabilize sludge and economize aeration energy. Effects of stabilization and sludge properties for AN-TAD process were evaluated by batch experiments during a 25 d digestion period. The sludges digested by AN-TAD process achieved the requirements for Class-A sludge standard. The sludge at total solid (TS) 5.4% had the highest value of decay coefficient K(d(55)) at 0.1851 d(-1) among the three TS contents according to the first-order kinetics equation. Oxidation reduction potential at below 0 mV remained for sludges at TSs of 6.5%, 5.4%, and 4.6% for at least 15 d because of initial hydrolytic-acidification. Concentrations of nitrogen and phosphorus in sludges at TSs of 6.5%, 5.4%, and 4.6% gradually increased up to the highest values in the supernatant during the initial 13 d, causing low utilized value in land application as a fertilizer. Prolonging the retention time for more than 15 d was considered because soluble phosphorus precipitated in the solid phase. High content of soluble organic matters of the soluble chemical oxygen demand, protein, and polysaccharide in the supernatant caused deterioration in sludge dewaterability rates.

Influence of hydraulic retention time on indigenous microalgae and activated sludge process.

PubMed

Anbalagan, Anbarasan; Schwede, Sebastian; Lindberg, Carl-Fredrik; Nehrenheim, Emma

2016-03-15

Integration of the microalgae and activated sludge (MAAS) process in municipal wastewater treatment and biogas production from recovered MAAS was investigated by studying the hydraulic retention time (HRT) of semi-continuous photo-bioreactors. An average total nitrogen (TN) removal efficiency (RE) of maximum 81.5 ± 5.1 and 64.6 ± 16.2% was achieved at 6 and 4 days HRT. RE of total phosphorous (TP) increased slightly at 6 days (80 ± 12%) HRT and stabilized at 4 days (56 ± 5%) and 2 days (55.5 ± 5.5%) HRT due to the fluctuations in COD and N/P mass ratio of the periodic wastewater. COD and organic carbon were removed efficiently and a rapidly settleable MAAS with a sludge volume index (SVI_10) of less than 117 mL g(-1) was observed at all HRTs. The anaerobic digestion of the untreated MAAS showed a higher biogas yield of 349 ± 10 mL g VS(-1) with 2 days HRT due to a low solids retention time (SRT). Thermal pretreatment of the MAAS (120 °C, 120 min) did not show any improvement with biogas production at 6 days (269 ± 3 (untreated) and 266 ± 16 (treated) mL gVS(-1)), 4 days (258 ± 11(untreated) and 263 ± 10 (treated) mL gVS(-1)) and 2 days (308 ± 19 mL (treated) gVS(-1)) HRT. Hence, the biogas potential tests showed that the untreated MAAS was a feasible substrate for biogas production. Results from this proof of concept support the application of MAAS in wastewater treatment for Swedish conditions to reduce aeration, precipitation chemicals and CO2 emissions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Digital image processing and analysis for activated sludge wastewater treatment.

PubMed

Khan, Muhammad Burhan; Lee, Xue Yong; Nisar, Humaira; Ng, Choon Aun; Yeap, Kim Ho; Malik, Aamir Saeed

2015-01-01

Activated sludge system is generally used in wastewater treatment plants for processing domestic influent. Conventionally the activated sludge wastewater treatment is monitored by measuring physico-chemical parameters like total suspended solids (TSSol), sludge volume index (SVI) and chemical oxygen demand (COD) etc. For the measurement, tests are conducted in the laboratory, which take many hours to give the final measurement. Digital image processing and analysis offers a better alternative not only to monitor and characterize the current state of activated sludge but also to predict the future state. The characterization by image processing and analysis is done by correlating the time evolution of parameters extracted by image analysis of floc and filaments with the physico-chemical parameters. This chapter briefly reviews the activated sludge wastewater treatment; and, procedures of image acquisition, preprocessing, segmentation and analysis in the specific context of activated sludge wastewater treatment. In the latter part additional procedures like z-stacking, image stitching are introduced for wastewater image preprocessing, which are not previously used in the context of activated sludge. Different preprocessing and segmentation techniques are proposed, along with the survey of imaging procedures reported in the literature. Finally the image analysis based morphological parameters and correlation of the parameters with regard to monitoring and prediction of activated sludge are discussed. Hence it is observed that image analysis can play a very useful role in the monitoring of activated sludge wastewater treatment plants.

Utilisation of energy from digester gas and sludge incineration at Hamburg's Köhlbrandhöft WWTP.

PubMed

Thierbach, R D; Hanssen, H

2002-01-01

At Hamburg's Köhlbrandhöft WWTP the demand for external energy supply is minimised by state of the art sludge treatment. The sludge is subjected to thickening, anaerobic digestion, dewatering, drying and incineration. The digester gas is used in a combined gas and steam turbine process. The sludge incineration also produces steam, which is also used in the steam turbine that follows the gas turbine. The turbines produce electricity, partially expanded steam is used for the sludge drying process. Heat from the condensation of vapours from sludge drying is used to heat the anaerobic digesters. The overall process requires no external heat or fuel and produces 60% of the WWTP's electricity demand.

Enhancing dewaterability of waste activated sludge by combined oxidative conditioning process with zero-valent iron and peroxymonosulfate.

PubMed

Zhou, Xu; Jin, Wenbiao; Chen, Hongyi; Chen, Chuan; Han, Songfang; Tu, Renjie; Wei, Wei; Gao, Shu-Hong; Xie, Guo-Jun; Wang, Qilin

2017-11-01

The enhancement of sludge dewaterability is of great importance for facilitating the sludge disposal during the operation of wastewater treatment plants. In this study, a novel oxidative conditioning approach was applied to enhance the dewaterability of waste activated sludge by the combination of zero-valent iron (ZVI) and peroxymonosulfate (PMS). It was found that the dewaterability of sludge was significantly improved after the addition of ZVI (0-4 g/g TSS) (TSS: total suspended solids) and PMS (0-1 g/g TSS). The optimal addition amount of ZVI and PMS was 0.25 g/g TSS and 0.1 g/g TSS, respectively, under which the capillary suction time of the sludge was reduced by approximately 50%. The decomposition of sludge flocs could contribute to the improved sludge dewaterability. Economic analysis demonstrated that the proposed conditioning process with ZVI and PMS was more economical than the ZVI + peroxydisulfate and the traditional Fenton conditioning processes.

Co-digestion of sewage sludge from external small WWTP's in a large plant

NASA Astrophysics Data System (ADS)

Miodoński, Stanisław

2017-11-01

Improving energy efficiency of WWTPs (Waste Water Treatment Plants) is crucial action of modern wastewater treatment technology. Technological treatment process optimization is important but the main goal will not be achieved without increasing production of renewable energy from sewage sludge in anaerobic digestion process which is most often used as sludge stabilization method on large WWTP's. Usually, anaerobic digestion reactors used for sludge digestion were designed with reserve and most of them is oversized. In many cases that reserve is unused. On the other hand, smaller WWTPs have problem with management of sewage sludge due to lack of adequately developed infrastructure for sludge stabilization. Paper shows an analysis of using a technological reserve of anaerobic digestion reactors at large WWTP (1 million P.E.) for sludge stabilization collected from smaller WWTP in a co-digestion process. Over 30 small WWTPs from the same region as the large WWTP were considered in this study. Furthermore, performed analysis included also evaluation of potential sludge disintegration pre-treatment for co-digestion efficiency improvement.

Analysis of Combustion Process of Sewage Sludge in Reference to Coals and Biomass

NASA Astrophysics Data System (ADS)

Środa, Katarzyna; Kijo-Kleczkowska, Agnieszka

2016-06-01

Production of sewage sludge is an inseparable part of the treatment process. The chemical and sanitary composition of sewage sludge flowing into the treatment plant is a very important factor determining the further use of the final product obtained in these plants. The sewage sludge is characterized by heterogeneity and multi-components properties, because they have characteristics of the classical and fertilizer wastes and energetic fuels. The thermal utilization of sewage sludge is necessary due to the unfavorable sanitary characteristics and the addition of the industrial sewage. This method ensures use of sewage sludge energy and return of expenditure incurred for the treatment of these wastes and their disposal. Sewage sludge should be analyzed in relation to conventional fuels (coals and biomass). They must comply with the applicable requirements, for example by an appropriate degree of dehydration, which guarantee the stable and efficient combustion. This paper takes the issue of the combustion process of the different sewage sludge and their comparison of the coal and biomass fuels.

Formation of aerobic granular sludge and the influence of the pH on sludge characteristics in a SBR fed with brewery/bottling plant wastewater.

PubMed

Stes, Hannah; Aerts, Sven; Caluwé, Michel; Dobbeleers, Thomas; Wuyts, Sander; Kiekens, Filip; D'aes, Jolien; De Langhe, Piet; Dries, Jan

2018-05-01

A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic granule formation when treating brewery/bottling plant wastewater by consistent application of a feast/famine regime. The experiment was divided into three major periods according to the different operational conditions: (I) no pH control and strong fluctuations in organic loading rate (OLR) (1.18 ± 0.25 kgCOD·(m 3 ·day) -1 ), (II) pH control and aeration control strategy to reduce OLR fluctuations (1.45 ± 0.65 kgCOD·(m 3 ·day) -1 ) and (III) no pH control and stable OLR (1.42 ± 0.18 kgCOD·(m 3 ·day) -1 ). Aerobic granule formation was successful after 80 days and maintained during the subsequent 380 days. The aerobic granular sludge was characterized by SVI 5 and SVI 30 values below 60 mL.g -1 and dominated by granular, dense structures. An oxygen uptake rate based aeration control strategy insured endogenous respiration at the end of the aerobic phase, resulting in stable SBR operation when the influent composition fluctuated. The quantitative polymerase chain reaction results show no significant enrichment of Accumulibacter or Competibacter during the granulation process. The 16S rRNA sequencing results indicate enrichment of other, possibly important species during aerobic granule formation while treating brewery wastewaters.

Improved anaerobic digestion of a thermally pretreated mixture of physicochemical sludge; broiler excreta and sugar cane wastes (SCW): Effect on organic matter solubilization, biodegradability and bioenergy production.

PubMed

Nava-Valente, Noemí; Alvarado-Lassman, Alejandro; Nativitas-Sandoval, Liliana S; Mendez-Contreras, Juan M

2016-01-01

Thermal pretreatment effect of a mixture of organic wastes (physicochemical sludge, excreta of broiler chickens and sugarcane wastes (SCW)) in the solubilization and biodegradability organic matter as well as bioenergy production by anaerobic digestion was evaluated. Two different mixtures of physicochemical sludge, excreta of broiler chickens and SCW (70%, 15%, 15% and 60%, 20%, 20% of VS, respectively) were treated at different temperatures (80 °C, 85 °C and 90 °C) and contact time (30, 60 and 90 min). Results indicate that, organic matter solubilization degree increased from 1.14 to 6.56%; subsequently, in the anaerobic digestion process, an increase of 50% in the volatile solids removal and 10% in biogas production was observed, while, retention time decreased from 23 up to 9 days. The results obtained were similar to pilot-scale. In both experimental scales it showed that the synergy produced by the simultaneous anaerobic digestion of different substrates could increase bioenergy production up to 1.3 L bio g(-1) VS removed and 0.82 L CH4 g(-1) VS removed. The treatment conditions presented in this study allow for large residue quantities to be treated and large bioenergy quantities to be produced (10% higher than during conventional treatment) without increasing the anaerobic digester volume.

The effectiveness of municipal sewage sludge application on the stabilization of Pb, Zn, and Cd in a soil contaminated from mining activities.

PubMed

Xenidis, A; Stouraiti, C; Moirou, A

2001-01-01

The effectiveness of municipal sewage sludge for the stabilisation of Pb, Zn and Cd in a heavily contaminated soil was evaluated by performing pot experiments on soil-sludge mixtures. The soil sample originated from the Montevecchio mining district, Sardinia, Italy, and presented high Pb, Zn and Cd content, as well as US EPA TCLP solubility values for Pb and Cd, which exceeded the respective regulatory limits. Sewage sludge application increased the soil pH. Stabilisation experiments showed that 10% w/w sewage sludge addition effectively reduced Pb and Cd solubilities below the TCLP regulatory limits. At the same addition rate, the EDTA extractable fraction of Pb, Zn, Cd in the treated soil was reduced by 12, 47 and 50% respectively compared with the untreated sample. The five-stage sequential extraction procedure applied on the untreated and treated soil samples, showed a remarkable shift of the metals towards more stable forms. The reducible fractions of Zn and Cd and the residual fraction of Pb were increased by 12, 20 and 18% respectively, while a corresponding decrease in the mobile fractions (exchangeable and carbonate) occurred which accounted for 14, 23 and 25% respectively.

PILOT-SCALE INCINERATION OF CONTAMINATED SLUDGES FROM THE BOFORS-NOBEL SUPERFUND SITE

EPA Science Inventory

A detailed test program was performed at the U.S. Environmental Protection Agency’s (EPA’s) Incineration Research Facility (IRF) to help determine the effectiveness of incineration in treating two contaminated lagoon sludges from the Bofors-Nobel Superfund site in Mus...

Aerobic granular sludge technology: Mechanisms of granulation and biotechnological applications.

PubMed

Nancharaiah, Y V; Kiran Kumar Reddy, G

2018-01-01

Aerobic granular sludge (AGS) is a novel microbial community which allows simultaneous removal of carbon, nitrogen, phosphorus and other pollutants in a single sludge system. AGS is distinct from activated sludge in physical, chemical and microbiological properties and offers compact and cost-effective treatment for removing oxidized and reduced contaminants from wastewater. AGS sequencing batch reactors have shown their utility in the treatment of abattoir, live-stock, rubber, landfill leachate, dairy, brewery, textile and other effluents. AGS is extensively researched for wide-spread implementation in sewage treatment plants. However, formation of AGS takes relatively much longer time while treating low-strength wastewaters like sewage. Strategies like increased volumetric flow by means of short cycles and mixing of sewage with industrial wastewaters can promote AGS formation while treating low-strength sewage. This article reviewed the state of research on AGS formation mechanisms, bioremediation capabilities and biotechnological applications of AGS technology in domestic and industrial wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using Chlorella vulgaris to treat toxic excess sludge extract, and identification of its response mechanism by proteomics approach.

PubMed

Wang, Lu; Wang, Hualin; Chen, Xiurong; Xu, Yan; Zhou, Tianjun; Wang, Xiaoxiao; Lu, Qian; Ruan, Roger

2018-04-01

Chlorella vulgaris was cultivated in varying proportions of toxic sludge extracts obtained from a sequencing batch reactor for treating synthetic wastewater containing chlorophenols. C. vulgaris could reduce the ecotoxicity from sludge extracts, and a positive correlation was noted between ecotoxicity removal and total organic carbon removal. In terms of cell density, the optimal proportion of sludge extracts required for the cultivation of C. vulgaris was lower than 50%. The correlation between protein content in per 10 6 algae and inhibition extent of ecotoxicity of the 5 groups on the day of inoculation (0.9182, p < .05) indicated a positive relationship between algal protein secretion and ecotoxicity. According to the protein expression and differential protein expression analysis, we concluded that C. vulgaris produced proteins that involved in the stress response/redox system and energy metabolism/biosynthesis to respond to the toxic environment and some other proteins related to mixotrophic metabolism. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of phytoavailability of heavy metals in tropical soils by modified Neubauer method (organic extractor).

NASA Astrophysics Data System (ADS)

Mellis, E. V.; Rodella, A. A.; Levy, C. C. B.

2012-04-01

Nowadays authors discuss the use of metal content phytoavailable in replacement of the total content to establish regulatory limits for metals in soils. However, there is still no patterning in the method to be used to estimate the phytoavailability of metals present in soils and is usually used extraction solutions such as: DTPA, Mehlich 3 and HCl. Although the use of these solutions is an alternative, these extractors have large efficacy variation according to the metal concentration in soil, soil type, the presence of other chemical species, plant species and the metal in question. An alternative would be to use biological methods, with the use of plants to assess the availability of metals that could be used in routine laboratories. The aim of this study was to determine the phytoavailability of Cd, Cu, Ni and Zn by the method of Neubauer, correlating levels of soluble metals determined by DTPA in soil treated with sewage sludge, and its absorption by rice plants. In this experiment it was used the modification proposed by Catani and Bergamin (1960) of the original procedure established by Neubauer and Schneider (1923). Studies were conducted on samples of a Rhodic soil (clayey), obtained in experiments in which sewage sludge was applied in corn, located in the Experimental Field of Embrapa Environment, Jaguariúna (SP), latitude 22o41 'south, longitude W. 47th Gr and altitude of 570 m. The sewage sludge were generated in the Stations of Sewage Treatment of Barueri (State of São Paulo, Brazil), which treats domestic and industrial sludge (Sludge Barueri - SB) and Stations of Sewage Treatment of Franca (State of São Paulo, Brazil), which deals mainly with domestic sludge (Sludge Franca - SF). The applications of sewage sludge were made from 1999 for five consecutive years and on average, it was applied the following amounts of sludge per year: 0, 5, 10, 20 and 40 t ha-1. It was evaluated the dry matter production, nutrient concentrations in the plant and the quantities of Cu, Ni and Zn extracted by plants. As a possible term of comparison with the contents of heavy metals in leaf tissue of rice, it might be considered to phytotoxic levels in mg kg-1: 30 to 20 for Cu, 50 to 100 for Ni and 500 to 1500 for Zn. The concentration of Cu extracted by rice plants had significant influence only for the amount of sludge factor regardless of its source. The elements Ni and Zn showed significant response to both doses of sludge used in the field, and for the type of sludge used, with the greatest accumulation of these metals in the samples treated with domestic and industrial sewage (Sludge Barueri - SB). Based on these results it can be concluded that the modified Neubauer method can be an efficient method for the determination of phytoavailable metals in soils, requiring further studies to confirm such efficiency.

Fate of pharmaceuticals in full-scale source separated sanitation system.

PubMed

Butkovskyi, A; Hernandez Leal, L; Rijnaarts, H H M; Zeeman, G

2015-11-15

Removal of 14 pharmaceuticals and 3 of their transformation products was studied in a full-scale source separated sanitation system with separate collection and treatment of black water and grey water. Black water is treated in an up-flow anaerobic sludge blanket (UASB) reactor followed by oxygen-limited autotrophic nitrification-denitrification in a rotating biological contactor and struvite precipitation. Grey water is treated in an aerobic activated sludge process. Concentration of 10 pharmaceuticals and 2 transformation products in black water ranged between low μg/l to low mg/l. Additionally, 5 pharmaceuticals were also present in grey water in low μg/l range. Pharmaceutical influent loads were distributed over two streams, i.e. diclofenac was present for 70% in grey water, while the other compounds were predominantly associated to black water. Removal in the UASB reactor fed with black water exceeded 70% for 9 pharmaceuticals out of the 12 detected, with only two pharmaceuticals removed by sorption to sludge. Ibuprofen and the transformation product of naproxen, desmethylnaproxen, were removed in the rotating biological contactor. In contrast, only paracetamol removal exceeded 90% in the grey water treatment system while removal of other 7 pharmaceuticals was below 40% or even negative. The efficiency of pharmaceutical removal in the source separated sanitation system was compared with removal in the conventional sewage treatment plants. Furthermore, effluent concentrations of black water and grey water treatment systems were compared with predicted no-effect concentrations to assess toxicity of the effluent. Concentrations of diclofenac, ibuprofen and oxazepam in both effluents were higher than predicted no-effect concentrations, indicating the necessity of post-treatment. Ciprofloxacin, metoprolol and propranolol were found in UASB sludge in μg/g range, while pharmaceutical concentrations in struvite did not exceed the detection limits. Copyright © 2015 Elsevier Ltd. All rights reserved.

Feedstock and process influence on biodiesel produced from waste sewage sludge.

PubMed

Capodaglio, Andrea G; Callegari, Arianna

2018-06-15

Disposal of sewage sludge is one of the most important issues in wastewater treatment throughout Europe, as EU sludge production, estimated at 9.5 million tons dry weight in 2005, is expected to approach 13 million tons in 2020. While sludge disposal costs may constitute 30-50% of the total operation costs of wastewater treatment processes, waste sewage sludge still contains resources that may be put to use, like nutrients and energy, that can be recovered through a variety of approaches. Research has shown that waste sewage sludge can be a valuable and very productive feedstock for biodiesel generation, containing lipids (the fats from which biofuels are extracted) in amounts that would require large areas cultivated with typical biodiesel feedstock, to produce, and at a much lower final cost. Several methods have been tested for the production of biodiesel from sewage sludge. To date, among the most efficient such process is pyrolysis, and in particular Microwave-Assisted Pyrolysis (MAP), under which process conditions are more favorable in energetic and economic terms. Sludge characteristics are very variable, depending on the characteristics of the wastewater-generating service area and on the wastewater treatment process itself. Each sludge can be considered a unique case, and as such experimental determination of the optimal biodiesel yields must be conducted on a case-by-case basis. In addition to biodiesel, other pyrolysis products can add to the energetic yield of the process (and not only). This paper discusses how feedstock properties and process characteristics may influence biodiesel (and other products) yield from pyrolytic (and in particular, MAP) processes, and discusses future possible technological developments. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Characteristics of water obtained by dewatering cyanobacteria-containing sludge formed during drinking water treatment, including C-, N-disinfection byproduct formation.

PubMed

Xu, Hangzhou; Pei, Haiyan; Jin, Yan; Xiao, Hongdi; Ma, Chunxia; Sun, Jiongming; Li, Hongmin

2017-03-15

This is the first study to systematically investigate the characteristics of the water obtained by dewatering cyanobacteria-containing sludge generated in the drinking water treatment plant, including formation of C- and N-disinfection by-products (DBPs). Results showed that this 'dewatering water' (DW) had different properties when the sludge was stored at different times. The content of dissolved organic matter (DOM) and microcystins (MCs) in the DW were low when the sludge was treated or disposed of within 4 days; correspondingly, the C-, N-DBP production was also low. However, due to the damage of algal cells to some extent, the DOM and MC levels increased significantly for storage time longer than 4 days; the production of C-, N-DBPs also increased. There were also obvious differences in the characteristics of the DW from sludges generated with different coagulant species. Due to the better protective effect of FeCl 3 and polymeric aluminium ferric chloride (PAFC) flocs, the DOM and MC levels and the production of C-, N-DBPs in the DW with FeCl 3 and PAFC coagulation were lower than those with AlCl 3 coagulation, even though the sludges were stored for the same amount of time. Furthermore, because of the formation of Al and Fe hydroxides, precipitated onto the surface of flocs, the soluble Al and Fe in the DW decreased with increased storage time, especially in the first four days. Overall, this study revealed the trends in variation of DW quality for cyanobacteria-containing sludges formed with different coagulants, then FeCl 3 and PAFC coagulants are recommended and sludge should be treated or disposed of within 4 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Assessment of microbial products in the biosorption process of Cu(II) onto aerobic granular sludge: Extracellular polymeric substances contribution and soluble microbial products release.

PubMed

Huang, Linxian; Li, Meilin; Si, Guangchao; Wei, Jinglin; Ngo, Huu Hao; Guo, Wenshan; Xu, Weiying; Du, Bin; Wei, Qin; Wei, Dong

2018-05-18

In the present study, the responses of microbial products in the biosorption process of Cu(II) onto aerobic granular sludge were evaluated by using batch and spectroscopic approaches. Batch experimental data showed that extracellular polymeric substances (EPSs) contributed to Cu(II) removal from an aqueous solution, especially when treating low metal concentrations, whereas soluble microbial products (SMPs) were released under the metal stress during biosorption process. A three-dimensional excitation-emission matrix (3D-EEM) identified four main fluorescence peaks in the EPS, i.e., tryptophan protein-like, aromatic protein-like, humic-like and fulvic acid-like substances, and their fluorescence intensities decreased gradually in the presence of Cu(II) during the sorption process. Particularly, tryptophan protein-like substances quenched the Cu(II) binding to a much higher extent through a static quenching process with less than one class of binding sites. According to the synchronous fluorescence spectra, the whole fluorescence intensity of released SMP samples expressed an increased trend with different degrees along with contact time. Two-dimensional correlation spectroscopy (2D-COS) suggested that the fulvic-like fluorescence fraction might be more susceptible to metal exposure than other fractions. The result of molecular weight distribution demonstrated that the SMPs released from the biosorption process differed significantly according to contact time. The result obtained could provide new insights into the responses of microbial products from aerobic granular sludge with heavy metal treatment. Copyright © 2018. Published by Elsevier Inc.

Evaluation of the simultaneous removal of recalcitrant drugs (bezafibrate, gemfibrozil, indomethacin and sulfamethoxazole) and biodegradable organic matter from synthetic wastewater by electro-oxidation coupled with a biological system.

PubMed

Rodríguez-Nava, Odín; Ramírez-Saad, Hugo; Loera, Octavio; González, Ignacio

2016-12-01

Pharmaceutical degradation in conventional wastewater treatment plants (WWTP) represents a challenge since municipal wastewater and hospital effluents contain pharmaceuticals in low concentrations (recalcitrant and persistent in WWTP) and biodegradable organic matter (BOM) is the main pollutant. This work shows the feasibility of coupling electro-oxidation with a biological system for the simultaneous removal of recalcitrant drugs (bezafibrate, gemfibrozil, indomethacin and sulfamethoxazole (BGIS)) and BOM from wastewater. High removal efficiencies were attained without affecting the performance of activated sludge. BGIS degradation was performed by advanced electrochemical oxidation and the activated sludge process for BOM degradation in a continuous reactor. The selected electrochemical parameters from microelectrolysis tests (1.2 L s(-1) and 1.56 mA cm(-2)) were maintained to operate a filter press laboratory reactor FM01-LC using boron-doped diamond as the anode. The low current density was chosen in order to remove drugs without decreasing BOM and chlorine concentration control, so as to avoid bulking formation in the biological process. The wastewater previously treated by FM01-LC was fed directly (without chemical modification) to the activated sludge reactor to remove 100% of BGIS and 83% of BOM; conversely, the BGIS contained in wastewater without electrochemical pre-treatment were persistent in the biological process and promoted bulking formation.

Multi-step process for concentrating magnetic particles in waste sludges

DOEpatents

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.

Multi-step process for concentrating magnetic particles in waste sludges

DOEpatents

Watson, J.L.

1990-07-10

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. 7 figs.

Lipid-enhancement of activated sludges obtained from conventional activated sludge and oxidation ditch processes.

PubMed

Revellame, Emmanuel D; Hernandez, Rafael; French, W Todd; Holmes, William E; Forks, Allison; Callahan, Robert

2013-11-01

Lipid-enhancement of activated sludges was conducted to increase the amount of saponifiable lipids in the sludges. The sludges were obtained from a conventional activated sludge (CAS) and an oxidation ditch process (ODP). Results showed 59-222% and 150-250% increase in saponifiable lipid content of the sludges from CAS and ODP, respectively. The fatty acid methyl ester (FAMEs) obtained from triacylglycerides was 57-67% (of total FAMEs) for enhanced CAS and 55-73% for enhanced ODP, a very significant improvement from 6% to 10% (CAS) and 4% to 8% (ODP). Regardless of the source, the enhancement resulted in sludges with similar fatty acid profile indicating homogenization of the lipids in the sludges. This study provides a potential strategy to utilize existing wastewater treatment facilities as source of significant amount of lipids for biofuel applications. Published by Elsevier Ltd.

Innovative treatment system for digester liquor using anammox process.

PubMed

Furukawa, Kenji; Inatomi, Yasuhiko; Qiao, Sen; Quan, Lai; Yamamoto, Taichi; Isaka, Kazuichi; Sumino, Tatsuo

2009-11-01

This study demonstrated that partial nitritation using nitrifying activated sludge entrapped in a polyethylene glycol (PEG) gel carrier, as a pretreatment to anammox process, could be successfully applied to digester liquor of biogas plant at a nitrogen loading rate of 3.0 kg-N/m(3)/d. The nitritation process produced an effluent with a NO(2)-N/NH(4)-N ratio between 1.0 and 1.4, which was found to be suitable for the subsequent anammox process. A high SS concentration (2000-3000 mg/l) in the digester liquor did not affect partial nitritation treatment performances. Effluent from this partial nitritation reactor was successfully treated in the anammox reactor using anammox sludge entrapped in the PEG gel carrier with T-N removal rates of greater than 4.0 kg-N/m(3)/d. Influent BOD and SS contents did not inhibit anammox activity of the anammox gel carrier. The combination of partial nitritation and anammox reactors using PEG entrapped nitrifying and anammox bacteria was shown to be effective for the removal of high concentration ammonium in the digester liquor of a biogas plant.

Application of dielectric constant measurement in microwave sludge disintegration and wastewater purification processes.

PubMed

Kovács, Petra Veszelovszki; Lemmer, Balázs; Keszthelyi-Szabó, Gábor; Hodúr, Cecilia; Beszédes, Sándor

2018-05-01

It has been numerously verified that microwave radiation could be advantageous as a pre-treatment for enhanced disintegration of sludge. Very few data related to the dielectric parameters of wastewater of different origins are available; therefore, the objective of our work was to measure the dielectric constant of municipal and meat industrial wastewater during a continuous flow operating microwave process. Determination of the dielectric constant and its change during wastewater and sludge processing make it possible to decide on the applicability of dielectric measurements for detecting the organic matter removal efficiency of wastewater purification process or disintegration degree of sludge. With the measurement of dielectric constant as a function of temperature, total solids (TS) content and microwave specific process parameters regression models were developed. Our results verified that in the case of municipal wastewater sludge, the TS content has a significant effect on the dielectric constant and disintegration degree (DD), as does the temperature. The dielectric constant has a decreasing tendency with increasing temperature for wastewater sludge of low TS content, but an adverse effect was found for samples with high TS and organic matter contents. DD of meat processing wastewater sludge was influenced significantly by the volumetric flow rate and power level, as process parameters of continuously flow microwave pre-treatments. It can be concluded that the disintegration process of food industry sludge can be detected by dielectric constant measurements. From technical purposes the applicability of dielectric measurements was tested in the purification process of municipal wastewater, as well. Determination of dielectric behaviour was a sensitive method to detect the purification degree of municipal wastewater.

Implications of changes in solids retention time on long term evolution of sludge filterability in anaerobic membrane bioreactors treating high strength industrial wastewater.

PubMed

Dereli, Recep Kaan; Grelot, Aurelie; Heffernan, Barry; van der Zee, Frank P; van Lier, Jules B

2014-08-01

Long-term experiments were conducted to assess the impact of changing the solids retention time (SRT) on sludge filterability in anaerobic membrane bioreactors (AnMBRs), treating corn-based bioethanol thin stillage. Well established parameters, such as capillary suction time (CST) and specific resistance to filtration (SRF), developed for sludge dewatering, were used to evaluate the SRT effect on sludge filterability. Our results clearly demonstrated that SRT is one of the most important factors influencing sludge filterability in AnMBRs. SRT effects the accumulation of fine particles and solutes, which were found to affect attainable flux and fouling, in reactor broth. A better filterability was observed at a SRT of 20 days compared to elevated SRTs, i.e. 50 days. A clear correlation between sludge filtration characteristics and membrane filtration resistance could not be established especially at short SRTs, whereas many parameters such as total suspended solids (TSS), CST, soluble microbial products (SMP) and supernatant filterability were found to be mutually correlated. Net membrane fluxes between 9 and 13 L m(-2) h(-1) were obtained at 0.5 m s(-1) cross-flow velocity and the long term fouling was controlled by using frequent filtration and backwash cycles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge with ultrasound and Fenton processes: Effect of system parameters and synergistic effect study.

PubMed

Lin, Meiqing; Ning, Xun-an; An, Taicheng; Zhang, Jianhao; Chen, Changmin; Ke, Yaowei; Wang, Yujie; Zhang, Yaping; Sun, Jian; Liu, Jingyong

2016-04-15

To establish an efficient oxidation process for the degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge, the effects of various operating parameters were optimized during the ultrasound process, Fenton process and the combined ultrasound-Fenton process. The results showed that the ultrasonic density of 1.80w/cm(3), both H2O2 and Fe(2+) dosages of 140mmol/L and pH 3 were favorable conditions for the degradation of PAHs. The degradation efficiency of high molecular weight PAHs was close to or even higher than that of light molecular weight PAHs. The highest degradation efficiencies of Σ16 PAHs were obtained within 30min in the order of: Fenton (83.5%) >ultrasound-Fenton (75.5%) >ultrasound (45.5%), then the efficiencies were decreased in the other of: ultrasound-Fenton (73.0%) >Fenton (70.3%) >ultrasound (41.4%) in 60min. The extra PAHs were released from the intracellular substances and the cavities of sludge due to the disruption of sludge during the oxidation process. Also, the degradation of PAHs could be inhibited by the other organic matter in the sludge. The combined ultrasound-Fenton process showed more efficient than both ultrasound process and Fenton process not only in the surface of sludge but also in the sludge interior. Copyright © 2015 Elsevier B.V. All rights reserved.

[Characteristics of odors and VOCs from sludge direct drying process].

PubMed

Chen, Wen-He; Deng, Ming-Jia; Luo, Hui; Zhang, Jing-Ying; Ding, Wen-Jie; Liu, Jun-Xin; Liu, Jun-Xin

2014-08-01

Co-processing sewage sludge by using the high-temperature feature of cement kiln can realize harmless disposal and energy recycling. In this paper, investigation on characteristics of the flue gas from sludge drying process was carried out in Guangzhou Heidelberg Yuexiu Cement Co., LTD. The composition and the main source of odors and volatile organic compounds (VOCs) emitted during the drying process were analyzed, aimed to provide scientific basis for the treatment of sewage sludge. Results showed that there were a large number of malodorous substances and VOCs in the flue gas. Sulfur dioxide and other sulfur-containing compounds were the main components in the malodorous substances, while benzene derivatives were predominant in VOCs. The compositions of odors and VOCs were influenced by the characteristics of the sludge and the heat medium (kiln tail gas). Total organic compounds in the sludge were significantly decreased after drying. Other organic substances such as volatile fatty acid, protein, and polysaccharide were also obviously reduced. The organic matter in sludge was the main source of VOCs in the flue gas. Part of sulfurous substances, such as sulfur dioxide, carbon disulfide, were from sulfur-containing substances in the sludge, and the rest were from the kiln tail gas itself.

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

PubMed

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.

ENHANCED CHEMICAL CLEANING: A NEW PROCESS FOR CHEMICALLY CLEANING SAVANNAH RIVER WASTE TANKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ketusky, E; Neil Davis, N; Renee Spires, R

2008-01-17

The Savannah River Site (SRS) has 49 high level waste (HLW) tanks that must be emptied, cleaned, and closed as required by the Federal Facilities Agreement. The current method of chemical cleaning uses several hundred thousand gallons per tank of 8 weight percent (wt%) oxalic acid to partially dissolve and suspend residual waste and corrosion products such that the waste can be pumped out of the tank. This adds a significant quantity of sodium oxalate to the tanks and, if multiple tanks are cleaned, renders the waste incompatible with the downstream processing. Tank space is also insufficient to store thismore » stream given the large number of tanks to be cleaned. Therefore, a search for a new cleaning process was initiated utilizing the TRIZ literature search approach, and Chemical Oxidation Reduction Decontamination--Ultraviolet (CORD-UV), a mature technology currently used for decontamination and cleaning of commercial nuclear reactor primary cooling water loops, was identified. CORD-UV utilizes oxalic acid for sludge dissolution, but then decomposes the oxalic acid to carbon dioxide and water by UV treatment outside the system being treated. This allows reprecipitation and subsequent deposition of the sludge into a selected container without adding significant volume to that container, and without adding any new chemicals that would impact downstream treatment processes. Bench top and demonstration loop measurements on SRS tank sludge stimulant demonstrated the feasibility of applying CORD-UV for enhanced chemical cleaning of SRS HLW tanks.« less

Comparison of three different wastewater sludge and their respective drying processes: Solar, thermal and reed beds - Impact on organic matter characteristics.

PubMed

Collard, Marie; Teychené, Benoit; Lemée, Laurent

2017-12-01

Drying process aims at minimising the volume of wastewater sludge (WWS) before disposal, however it can impact sludge characteristics. Due to its high content in organic matter (OM) and lipids, sludge are mainly valorised by land farming but can also be considered as a feedstock for biodiesel production. As sludge composition is a major parameter for the choice of disposal techniques, the objective of this study was to determine the influence of the drying process. To reach this goal, three sludges obtained from solar, reed beds and thermal drying processes were investigated at the global and molecular scales. Before the drying step the sludges presented similar physico-chemical (OM content, elemental analysis, pH, infrared spectra) characteristics and lipid contents. A strong influence of the drying process on lipids and humic-like substances contents was observed through OM fractionation. Thermochemolysis-GCMS of raw sludge and lipids revealed similar molecular content mainly constituted with steroids and fatty acids. Molecular changes were noticeable for thermal drying through differences in branched to linear fatty acids ratio. Finally the thermal drying induced a weakening of OM whereas the solar drying led to a complexification. These findings show that smooth drying processes such as solar or reed-beds are preferable for amendment production whereas thermal process leads to pellets with a high lipid content which could be considered for fuel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Decline of phosphorus, copper, and zinc in anaerobic lagoon columns receiving pretreated influent

USDA-ARS?s Scientific Manuscript database

Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. These lagoons usually require a sludge management plan for their maintenance consisting of regular sludge removal by mechanical agitation and pumping followed by land application at agr...

Research Findings on Heat Treatment of Pathogens and Indicator Organisms

EPA Science Inventory

Heat or thermal treatment has been used for many years for reducing the densities of pathogens in food and beverages. Its application for disinfection of municipal sludges has occurred only recently. One method for achieving Class A biosolids is to thermally treat sludges either ...

Start-up period investigation of pilot-scale submerged membrane electro-bioreactor (SMEBR) treating raw municipal wastewater.

PubMed

Hasan, Shadi W; Elektorowicz, Maria; Oleszkiewicz, Jan A

2014-02-01

Submerged membrane electro-bioreactor (SMEBR) is a new hybrid technology for wastewater treatment employing electrical field and microfiltration in a nutrient-removing activated sludge process. A pilot SMEBR system was located at the wastewater treatment plant in the City of l'Assomption (Quebec, Canada) with the objective of investigating the start-up period performance under variable organic loadings and environmental conditions with respect to effluent quality, membrane fouling, and sludge properties. The pilot SMEBR facility was fed with the raw de-gritted municipal wastewater. At steady state operation, the removal efficiencies of ammonia (as NH3(+)-N), phosphorus (as PO4(3-)-P), and COD were 99%, 99%, and 92%, respectively. No substantial increase in the monitored transmembrane pressure as 0.02kPad(-1) was reported. The time necessary to filter 100mL of the sludge sample has decreased by 78% after treatment whilst the sludge volume index averaged 119mLg(-1). Energy requirements were in the range of 1.1-1.6kWhm(-3) of wastewater. It was concluded that the SMEBR is a very competitive technology when compared to conventional membrane systems as it can enhance treatment performance to an appreciable extent, remove phosphorus and reduce fouling. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Male-Specific Coliphages as Indicators of Thermal Inactivation of Pathogens in Biosolids

PubMed Central

Nappier, Sharon P.; Aitken, Michael D.; Sobsey, Mark D.

2006-01-01

Male-specific (F+) coliphages have been proposed as a candidate indicator of fecal contamination and of virus reduction in waste treatment. However, in this and earlier work with a laboratory thermophilic anaerobic digester, a heat-resistant fraction of F+ coliphage populations indigenous to municipal wastewater and sludge was evident. We therefore isolated coliphages from municipal wastewater sludge and from biosolid samples after thermophilic anaerobic digestion to evaluate the susceptibility of specific groups to thermal inactivation. Similar numbers of F+ DNA and F+ RNA coliphages were found in untreated sludge, but the majority of isolates in digested biosolids were group I F+ RNA phages. Separate experiments on individual isolates at 53°C confirmed the apparent heat resistance of group I F+ RNA coliphages as well as the susceptibility of group III F+ RNA coliphages. Although few F+ DNA coliphages were recovered from the treated biosolid samples, thermal inactivation experiments indicated heat resistance similar to that of group I F+ RNA phages. Hence, F+ DNA coliphage reductions during thermophilic anaerobic digestion are probably related to mechanisms other than thermal inactivation. Further studies should focus on the group III F+ RNA coliphages as potential indicators of reductions of heat-resistant pathogens in thermal processes for sludge treatment. PMID:16597945

Efficient Phosphorus Cycling in Food Production: Predicting the Phosphorus Fertilization Effect of Sludge from Chemical Wastewater Treatment.

PubMed

Falk Øgaard, Anne; Brod, Eva

2016-06-22

This study examined the P fertilization effects of 11 sewage sludges obtained from sewage treated with Al and/or Fe salts to remove P by a pot experiment with ryegrass (Lolium multiflorum) and a nutrient-deficient sand-peat mixture. Also it investigated whether fertilization effects could be predicted by chemical sludge characteristics and/or by P extraction. The mineral fertilizer equivalent (MFE) value varied significantly but was low for all sludges. MFE was best predicted by a negative correlation with ox-Al and ox-Fe in sludge, or by a positive correlation with P extracted with 2% citric acid. Ox-Al had a greater negative impact on MFE than ox-Fe, indicating that Fe salts are preferable as a coagulant when aiming to increase the plant availability of P in sludge. The results also indicate that sludge liming after chemical wastewater treatment with Al and/or Fe salts increases the P fertilization effect.

The hydrolysis and biogas production of complex cellulosic substrates using three anaerobic biomass sources.

PubMed

Keating, C; Cysneiros, D; Mahony, T; O'Flaherty, V

2013-01-01

In this study, the ability of various sludges to digest a diverse range of cellulose and cellulose-derived substrates was assessed at different temperatures to elucidate the factors affecting hydrolysis. For this purpose, the biogas production was monitored and the specific biogas activity (SBA) of the sludges was employed to compare the performance of three anaerobic sludges on the degradation of a variety of complex cellulose sources, across a range of temperatures. The sludge with the highest performance on complex substrates was derived from a full-scale bioreactor treating sewage at 37 °C. Hydrolysis was the rate-limiting step during the degradation of complex substrates. No activity was recorded for the synthetic cellulose compound carboxymethylcellulose (CMC) using any of the sludges tested. Increased temperature led to an increase in hydrolysis rates and thus SBA values. The non-granular nature of the mesophilic sludge played a positive role in the hydrolysis of solid substrates, while the granular sludges proved more effective on the degradation of soluble compounds.

[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].

PubMed

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

2011-07-01

To observe the bioleaching effect on sewage sludge dewaterability, three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume. Subsequently, the bioleached sludge was dewatered by using chamber filter press. The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1: 15 mixing ratio of bioleached sludge to raw sludge. The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial -134 mV to finial 507 mV. The specific resistance to filtration (SRF) of the tested sludge was decreased from original 1.00 x 10(13) m/kg to final 0.09 x 10(13) m/kg after bioleaching. For the subsequent two batch trials, the bioleaching process can be finished in 40 hours and 46 hours, respectively. Likewise, sludge SRF is also significantly decreased to 0.19 x 10(13) m/kg and 0.36 x 10(13) m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1:1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd, and 3rd batch experiments, respectively. The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours. It is found that the moisture of dewatered sludge cake can be reduced to 58%, and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor. In addition, it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%, but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process. Therefore, dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above. Therefore, bioleaching technique is of great engineering application for the treatment of sewage sludge.

Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge.

PubMed

Zhu, Yi; Zeng, Guangming; Zhang, Panyue; Zhang, Chang; Ren, Miaomiao; Zhang, Jiachao; Chen, Ming

2013-08-01

Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of ultrasonic and ozone pre-treatments on pharmaceutical waste activated sludge's solubilisation, reduction, anaerobic biodegradability and acute biological toxicity.

PubMed

Pei, Jin; Yao, Hong; Wang, Hui; Shan, Dan; Jiang, Yichen; Ma, Lanqianya; Yu, Xiaohua

2015-09-01

Ultrasonic and ozone pre-treatment technologies were employed in this study to improve the anaerobic digestion efficiency of pharmaceutical waste activated sludge. The sludge solubilisation achieved 30.01% (150,000 kJ/kg TS) and 28.10% (0.1g O3/g TS) after ultrasonic treatment and ozone treatment. The anaerobic biodegradability after ultrasonic treatment was higher compared to ozonation due to the higher cumulative methane volume observed after 6 days (249 ml vs 190 ml). The ozonated sludge released the highest concentration of Cu(2+) into the liquid phase (6.640 mg L(-1)) compared to 0.530 mg/L for untreated sludge and 0.991 mg/L for sonicated sludge. The acute toxicity test measured by luminescent bacteria showed that anaerobic digestion could degrade toxic compounds and result in a reduction in toxicity. The main mechanism of action led to some differences in the treated sludge exhibiting higher potential for methane production from pharmaceutical waste sludge with ultrasonic treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization aspects of the biological nitrogen removal process in a full-scale twin sequencing batch reactor (SBR) system in series treating landfill leachate.

PubMed

Remmas, Nikolaos; Ntougias, Spyridon; Chatzopoulou, Marianna; Melidis, Paraschos

2018-03-29

Despite the fact that biological nitrogen removal (BNR) process has been studied in detail in laboratory- and pilot-scale sequencing batch reactor (SBR) systems treating landfill leachate, a limited number of research works have been performed in full-scale SBR plants regarding nitrification and denitrification. In the current study, a full-scale twin SBR system in series of 700 m 3 (350 m 3 each) treating medium-age landfill leachate was evaluated in terms of its carbon and nitrogen removal efficiency in the absence and presence of external carbon source, i.e., glycerol from biodiesel production. Both biodegradable organic carbon and ammonia were highly oxidized [biochemical oxygen demand (BOD 5 ) and total Kjehldahl nitrogen (TKN) removal efficiencies above 90%], whereas chemical oxygen demand (COD) removal efficiency was slightly above 40%, which is within the range reported in the literature for pilot-scale SBRs. As the consequence of the high recalcitrant organic fraction of the landfill leachate, dissimilatory nitrate reduction was restricted in the absence of crude glycerol, although denitrification was improved by electron donor addition, resulting in TN removal efficiencies above 70%. Experimental data revealed that the second SBR negligibly contributed to BNR process, since carbon and ammonia oxidation completion was achieved in the first SBR. On the other hand, the low VSS/SS ratio, due to the lack of primary sedimentation, highly improved sludge settleability, resulting in sludge volume indices (SVI) below 30 mL g -1 .

Study on the combined sewage sludge pyrolysis and gasification process: mass and energy balance.

PubMed

Wang, Zhonghui; Chen, Dezhen; Song, Xueding; Zhao, Lei

2012-12-01

A combined pyrolysis and gasification process for sewage sludge was studied in this paper for the purpose of its safe disposal with energy self-balance. Three sewage sludge samples with different dry basis lower heat values (LHV(db)) were used to evaluate the constraints on this combined process. Those samples were pre-dried and then pyrolysed within the temperature range of 400-550 degrees C. Afterwards, the char obtained from pyrolysis was gasified to produce fuel gas. The experimental results showed that the char yield ranged between 37.28 and 53.75 wt% of the dry sludge and it changed with ash content, pyrolysis temperature and LHV(db) of the sewage sludge. The gas from char gasification had a LHV around 5.31-5.65 MJ/Nm3, suggesting it can be utilized to supply energy in the sewage sludge drying and pyrolysis process. It was also found that energy balance in the combined process was affected by the LHV(db) of sewage sludge, moisture content and pyrolysis temperature. Higher LHV(db), lower moisture content and higher pyrolysis temperature benefit energy self-balance. For sewage sludge with a moisture content of 80 wt%, LHV(db) of sewage sludge should be higher than 18 MJ/kg and the pyrolysis temperature should be higher than 450 degrees C to maintain energy self-sufficiency when volatile from the pyrolysis process is the only energy supplier; when the LHV(db) was in the range of 14.65-18 MJ/kg, energy self-balance could be maintained in this combined process with fuel gas from char gasification as a supplementary fuel; auxiliary fuel was always needed if the LHV(db) was lower than 14.65 MJ/kg.

Transformation of heavy metal speciation during sludge drying: mechanistic insights.

PubMed

Weng, Huan-Xin; Ma, Xue-Wen; Fu, Feng-Xia; Zhang, Jin-Jun; Liu, Zan; Tian, Li-Xun; Liu, Chongxuan

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized Cr, Cu, Cd, and Pb in sludge by transforming acid-soluble, reducible, and oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge. Copyright © 2013 Elsevier B.V. All rights reserved.

Investigation of effects of background water on upwelled reflectance spectra and techniques for analysis of dilute primary-treated sewage sludge

NASA Technical Reports Server (NTRS)

Whitlock, C. H.; Usry, J. W.; Witte, W. G.; Farmer, F. H.; Gurganus, E. A.

1979-01-01

In an effort to improve understanding of the effects of variations in background water on reflectance spectra, laboratory tests were conducted with various concentrations of sewage sludge diluted with several types of background water. The results from these tests indicate that reflectance spectra for sewage-sludge mixtures are dependent upon the reflectance of the background water. Both the ratio of sewage-sludge reflectance to background-water reflectance and the ratio of the difference in reflectance to background-water reflectance show spectral variations for different turbid background waters. The difference in reflectance is the only parameter considered.

Combined effects of Fenton peroxidation and CaO conditioning on sewage sludge thermal drying.

PubMed

Liu, Huan; Liu, Peng; Hu, Hongyun; Zhang, Qiang; Wu, Zhenyu; Yang, Jiakuan; Yao, Hong

2014-12-01

Joint application of Fenton's reagent and CaO can dramatically enhance sludge dewaterability, thus are also likely to affect subsequent thermal drying process. This study investigated the synergistic effects of the two conditioners on the thermal drying behavior of sewage sludge and the emission characteristics of main sulfur-/nitrogen-containing gases. According to the results, Fenton peroxidation combined with CaO conditioning efficiently promoted sludge heat transfer, reduced the amounts of both free and bound water, and created porous structure in solids to provide evaporation channels, thus producing significant positive effects on sludge drying performance. In this case, the required time for drying was shortened to one-third. Additionally, joint usage of Fenton's reagent and CaO did not increase the losses of organic matter during sludge drying process. Meanwhile, they facilitated the formation of sulfate and sulfonic acid/sulfone, leading to sulfur retention in dried sludge. Both of Fenton peroxidation and CaO conditioning promoted the oxidation, decomposition, and/or dissolution of protein and inorganic nitrogen in sludge pre-treatment. As a consequence, the emissions of sulfurous and nitrogenous gases from dewatered sludge drying were greatly suppressed. These indicate that combining Fenton peroxidation with CaO conditioning is a promising strategy to improve drying efficiency of sewage sludge and to control sulfur and nitrogen contaminants during sludge thermal drying process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Fate of cyanobacteria in drinking water treatment plant lagoon supernatant and sludge.

PubMed

Pestana, Carlos J; Reeve, Petra J; Sawade, Emma; Voldoire, Camille F; Newton, Kelly; Praptiwi, Radisti; Collingnon, Lea; Dreyfus, Jennifer; Hobson, Peter; Gaget, Virginie; Newcombe, Gayle

2016-09-15

In conventional water treatment processes, where the coagulation and flocculation steps are designed to remove particles from drinking water, cyanobacteria are also concentrated into the resultant sludge. As a consequence, cyanobacteria-laden sludge can act as a reservoir for metabolites such as taste and odour compounds and cyanotoxins. This can pose a significant risk to water quality where supernatant from the sludge treatment facility is returned to the inlet to the plant. In this study the complex processes that can take place in a sludge treatment lagoon were investigated. It was shown that cyanobacteria can proliferate in the conditions manifest in a sludge treatment lagoon, and that cyanobacteria can survive and produce metabolites for at least 10days in sludge. The major processes of metabolite release and degradation are very dependent on the physical, chemical and biological environment in the sludge treatment facility and it was not possible to accurately model the net effect. For the first time evidence is provided to suggest that there is a greater risk associated with recycling sludge supernatant than can be estimated from the raw water quality, as metabolite concentrations increased by up to 500% over several days after coagulation, attributed to increased metabolite production and/or cell proliferation in the sludge. Copyright © 2016 Elsevier B.V. All rights reserved.

SLUDGE WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS FOR SLUDGE BATCH 7A QUALIFICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Billings, A.; Click, D.

2011-07-08

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry (Sludge Batch 7a*) be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from H Canyon are oftenmore » added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). Sludge Batch 7a (SB7a) is composed of portions of Tanks 4, 7, and 12; the Sludge Batch 6 heel in Tank 51; and a plutonium stream from H Canyon. SRNL received the Tank 51 qualification sample (sample ID HTF-51-10-125) following sludge additions to Tank 51. This report documents: (1) The washing (addition of water to dilute the sludge supernate) and concentration (decanting of supernate) of the SB7a - Tank 51 qualification sample to adjust sodium content and weight percent insoluble solids to Tank Farm projections. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the washed Tank 51 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a non-radioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the initial slurry samples and samples after each phase of CPC processing. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7a related data together in a single permanent record and to discuss the overall aspects of SB7a processing.« less

Performance comparison of biofilm and suspended sludge from a sequencing batch biofilm reactor treating mariculture wastewater under oxytetracycline stress.

PubMed

Zheng, Dong; Gao, Mengchun; Wang, Zhe; She, Zonglian; Jin, Chunji; Chang, Qingbo

2016-09-01

The performance, extracellular polymeric substances (EPS) and microbial community of a sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater under oxytetracycline stress. The chemical oxygen demand and [Formula: see text]-N removal efficiencies of the SBBR decreased with the increase of oxytetracycline concentration, and no obvious [Formula: see text]-N and [Formula: see text]-N accumulation in the effluent appeared at less than 10 mg L(-1) oxytetracycline. The specific oxygen utilization rate of the suspended sludge was more than that of the biofilm at different oxytetracycline concentrations. The specific ammonium oxidation rate (SAOR) of the biofilm was more easily affected by oxytetracycline than that of the suspended sludge, whereas the effect of oxytetracycline on the specific nitrite oxidation rate (SNOR) of the biofilm was less than that of the suspended sludge. The specific nitrate reduction rate of both the biofilm and suspended sludge was higher than the sum of the SAOR and SNOR at different oxytetracycline concentrations. The protein and polysaccharide contents in the EPS of the biofilm and suspended sludge increased with the increase of oxytetracycline concentration. The appearance of oxytetracycline in the influent could affect the chemical composition of the loosely bound EPS and tightly bound EPS. The amino, carboxyl and hydroxyl groups might be involved with interaction between EPS and oxytetracycline. The denaturing gradient gel electrophoresis profiles indicated that the variation of oxytetracycline concentration in the influent could affect the microbial communities of both the biofilm and suspended sludge.

Environmentally safe sewage sludge disposal: the impact of liming on the behaviour of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn.

PubMed

Scancar, J; Milacic, R; Strazar, M; Burica, O; Bukovec, P

2001-02-01

Dewatered sewage sludge containing relatively high total concentrations of Cr (945 micrograms ml-1), Cu (523 micrograms ml-1), Ni (1186 micrograms ml-1) and Zn (2950 micrograms ml-1) was treated with quicklime and sawdust for sludge disinfection and post-stabilisation. The mobility of the heavy metals in the sludge samples was assessed by applying a modified five-step Tessier sequential extraction procedure. Water was added as a first step for estimation of the proportion of the easily soluble metal fractions. To check the precision of the analytical work the concentrations of heavy metals in steps 1-6 of the extraction procedure were summed and compared to the total metal concentrations. The mass balance agreed within +/- 3% for Cd, Cu, Cr, and Zn and within +/- 5% for Ni, Pb, Fe and Mn. Data from the partitioning study indicate that in the lime-treated sludge at a pH of 12 the mobility of Cu and Ni notably increased with the solubilisation of these metals from their organic and/or carbonate and Fe and Mn oxide and hydroxide fractions, respectively. Liming slightly decreased the proportion of other heavy metals in the easily soluble fractions while its impact on the partitioning between other sludge phases was almost insignificant. Due to the increased solubility of Ni and Cu as well as potential Cr oxidation at high pH, liming cannot be recommended for sludge disinfection. Addition of sawdust did not change the heavy metal partitioning.

Sludge stabilization through aerobic digestion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartman, R.B.; Smith, D.G.; Bennett, E.R.

1979-10-01

The aerobic digestion process with certain modifications is evaluated as an alternative for sludge processing capable of developing a product with characteristics required for land application. Environmental conditions, including temperature, solids concentration, and digestion time, that affect the aerobic digestion of a mixed primary sludge-trickling filter humus are investigated. Variations in these parameters that influence the characteristics of digested sludge are determined, and the parameters are optimized to: provide the maximum rate of volatile solids reduction; develop a stable, nonodorous product sludge; and provide the maximum rate of oxidation of the nitrogenous material present in the feed sludge. (3 diagrams,more » 9 graphs, 15 references, 3 tables)« less

Research on soybean protein wastewater treatment by the integrated two-phase anaerobic reactor

PubMed Central

Yu, Yaqin

2015-01-01

The start-up tests of treating soybean protein wastewater by the integrated two-phase anaerobic reactor were studied. The results showed that the soybean protein wastewater could be successfully processed around 30 days when running under the situation of dosing seed sludge with the influent of approximately 2000 mg/L and an HRT of 40 h. When the start-up was finished, the removal rate of COD by the reactor was about 80%. In the zone I, biogas mainly revealed carbon dioxide (CO2) and hydrogen (H2). Methane was the main component in the zone 2 which ranged from 53% to 59% with an average of 55%. The methane content in biogas increased from the zone I to II. It indicated that the methane-producing capacity of the anaerobic sludge increased. It was found that the uniquely designed two-phase integrated anaerobic reactor played a key role in treating soybean protein wastewater. The acidogenic fermentation bacteria dominated in the zone I, while methanogen became dominant in the zone II. It realized the relatively effective separation of hydrolysis acidification and methanogenesis process in the reactor, which was benefit to promote a more reasonable space distribution of the microbial communities in the reactor. There were some differences between the activities of the sludge in the two reaction zones of the integrated two-phase anaerobic reactor. The activity of protease was higher in the reaction zone I. And the coenzyme F420 in the reaction zone II was twice than that in the reaction zone I, which indicated that the activity of the methanogens was stronger in the reaction zone II. PMID:26288554

A comparison of aerobic granular sludge with conventional and compact biological treatment technologies.

PubMed

Bengtsson, Simon; de Blois, Mark; Wilén, Britt-Marie; Gustavsson, David

2018-03-20

The aerobic granular sludge (AGS) technology is growing towards becoming a mature option for new municipal wastewater treatment plants and capacity extensions. A process based on AGS was compared to conventional activated sludge processes (with and without enhanced biological phosphorus removal), an integrated fixed-film activated sludge (IFAS) process and a membrane bioreactor (MBR) by estimating the land area demand (footprint), electricity demand and chemicals' consumption. The process alternatives compared included pre-settling, sludge digestion and necessary post-treatment to achieve effluent concentrations of 8 mg/L nitrogen and 0.2 mg/L phosphorus at 7°C. The alternative based on AGS was estimated to have a 40-50% smaller footprint and 23% less electricity requirement than conventional activated sludge. In relation to the other compact treatment options IFAS and MBR, the AGS process had an estimated electricity usage that was 35-70% lower. This suggests a favourable potential for processes based on AGS although more available experience of AGS operation and performance at full scale is desired.

Sequential anaerobic/aerobic digestion for enhanced sludge stabilization: comparison of the process performance for mixed and waste sludge [corrected].

PubMed

Tomei, M Concetta; Carozza, Nicola Antonello

2015-05-01

Sequential anaerobic-aerobic digestion has been demonstrated as a promising alternative for enhanced sludge stabilization. In this paper, a feasibility study of the sequential digestion applied to real waste activated sludge (WAS) and mixed sludge is presented. Process performance is evaluated in terms of total solid (TS) and volatile solid (VS) removal, biogas production, and dewaterability trend in the anaerobic and double-stage digested sludge. In the proposed digestion lay out, the aerobic stage was operated with intermittent aeration to reduce the nitrogen load recycled to the wastewater treatment plant (WWTP). Experimental results showed a very good performance of the sequential digestion process for both waste and mixed sludge, even if, given its better digestibility, higher efficiencies are observed for mixed sludge. VS removal efficiencies in the anaerobic stage were 48 and 50% for waste and mixed sludge, respectively, while a significant additional improvement of the VS removal of 25% for WAS and 45% for mixed sludge has been obtained in the aerobic stage. The post-aerobic stage, operated with intermittent aeration, was also efficient in nitrogen removal, providing a significant decrease of the nitrogen content in the supernatant: nitrification efficiencies of 90 and 97% and denitrification efficiencies of 62 and 70% have been obtained for secondary and mixed sludges, respectively. A positive effect due to the aerobic stage was also observed on the sludge dewaterability in both cases. Biogas production, expressed as Nm(3)/(kgVSdestroyed), was 0.54 for waste and 0.82 for mixed sludge and is in the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days.

Method for treating materials for solidification

DOEpatents

Jantzen, Carol M.; Pickett, John B.; Martin, Hollis L.

1995-01-01

A method for treating materials such as wastes for solidification to form a solid, substantially nonleachable product. Addition of reactive silica rather than ordinary silica to the material when bringing the initial molar ratio of its silica constituent to a desired ratio within a preselected range increases the solubility and retention of the materials in the solidified matrix. Materials include hazardous, radioactive, mixed, and heavy metal species. Amounts of other constituents of the material, in addition to its silica content are also added so that the molar ratio of each of these constituents is within the preselected ranges for the final solidified product. The mixture is then solidified by cement solidification or vitrification. The method can be used to treat a variety of wastes, including but not limited to spent filter aids from waste water treatment, waste sludges, combinations of spent filter aids and waste sludges, combinations of supernate and waste sludges, incinerator ash, incinerator offgas blowdown, combinations of incinerator ash and offgas blowdown, cementitious wastes and contaminated soils.

Diversity and degradation mechanism of an anaerobic bacterial community treating phenolic wastewater with sulfate as an electron acceptor.

PubMed

Guo, X J; Lu, Z Y; Wang, P; Li, H; Huang, Z Z; Lin, K F; Liu, Y D

2015-10-01

Petrochemical wastewater often contains high concentrations of phenol and sulfate that must be properly treated to meet discharge standards. This study acclimated anaerobic-activated sludge to treat saline phenolic wastewater with sulfate reduction and clarified the diversity and degradation mechanism of the microbial community. The active sludge in an upflow anaerobic sludge blanket (UASB) reactor could remove 90 % of phenol and maintain the effluent concentration of SO4 (2-) below 400 mg/L. Cloning and sequencing showed that Clostridium spp. and Desulfotomaculum spp. were major phenol-degrading bacteria. Phenol was probably degraded through the carboxylation pathway and sulfate reduction catalyzed by adenosine-5'-phosphosulfate (APS) reductase and dissimilatory sulfite reductase (DSR). A real-time polymerase chain reaction (RT-PCR) showed that as phenol concentration increased, the quantities of 16S rRNA gene, dsrB, and mcrA in the sludge all decreased. The relative abundance of dsrB dropped to 12.46 %, while that of mcrA increased to 56.18 %. The change in the electron flow ratio suggested that the chemical oxygen demand (COD) was removed mainly by sulfate-reducing bacteria under a phenol concentration of 420 mg/L, whereas it was removed mainly by methanogens above 630 mg/L.

Sludge reduction and water quality improvement in anaerobic lagoons through influent pre-treatment

USDA-ARS?s Scientific Manuscript database

Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. These lagoons may require cleanup and closure measures in the future. In practice, liquid and sludge need to be removed by pumping, usually at great expense of energy, and land applied ...

Activated Sludge. Student Manual. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Boe, Owen K.; Klopping, Paul H.

This student manual contains the textual material for a seven-lesson unit on activated sludge. Topic areas addressed in the lessons include: (1) activated sludge concepts and components (including aeration tanks, aeration systems, clarifiers, and sludge pumping systems); (2) activated sludge variations and modes; (3) biological nature of activated…

Vancomycin resistant enterococci (VRE) in Swedish sewage sludge.

PubMed

Sahlström, Leena; Rehbinder, Verena; Albihn, Ann; Aspan, Anna; Bengtsson, Björn

2009-05-29

Antimicrobial resistance is a serious threat in veterinary medicine and human healthcare. Resistance genes can spread from animals, through the food-chain, and back to humans. Sewage sludge may act as the link back from humans to animals. The main aims of this study were to investigate the occurrence of vancomycin resistant enterococci (VRE) in treated sewage sludge, in a Swedish waste water treatment plant (WWTP), and to compare VRE isolates from sewage sludge with isolates from humans and chickens. During a four month long study, sewage sludge was collected weekly and cultured for VRE. The VRE isolates from sewage sludge were analysed and compared to each other and to human and chicken VRE isolates by biochemical typing (PhenePlate), PFGE and antibiograms. Biochemical typing (PhenePlate-FS) and pulsed field gel electrophoresis (PFGE) revealed prevalence of specific VRE strains in sewage sludge for up to 16 weeks. No connection was found between the VRE strains isolated from sludge, chickens and humans, indicating that human VRE did not originate from Swedish chicken. This study demonstrated widespread occurrence of VRE in sewage sludge in the studied WWTP. This implies a risk of antimicrobial resistance being spread to new farms and to the society via the environment if the sewage sludge is used on arable land.

Reduction in greenhouse gas emissions from sludge biodrying instead of heat drying combined with mono-incineration in China.

PubMed

Liu, Hong-Tao; Wang, Yan-Wen; Liu, Xiao-Jie; Gao, Ding; Zheng, Guo-di; Lei, Mei; Guo, Guang-Hui; Zheng, Hai-Xia; Kong, Xiang-Juan

2017-02-01

Sludge is an important source of greenhouse gas (GHG) emissions, both in the form of direct process emissions and as a result of indirect carbon-derived energy consumption during processing. In this study, the carbon budgets of two sludge disposal processes at two well-known sludge disposal sites in China (for biodrying and heat-drying pretreatments, both followed by mono-incineration) were quantified and compared. Total GHG emissions from heat drying combined with mono-incineration was 0.1731 tCO 2 e t -1 , while 0.0882 tCO 2 e t -1 was emitted from biodrying combined with mono-incineration. Based on these findings, a significant reduction (approximately 50%) in total GHG emissions was obtained by biodrying instead of heat drying prior to sludge incineration. Sludge treatment results in direct and indirect greenhouse gas (GHG) emissions. Moisture reduction followed by incineration is commonly used to dispose of sludge in China; however, few studies have compared the effects of different drying pretreatment options on GHG emissions during such processes. Therefore, in this study, the carbon budgets of sludge incineration were analyzed and compared following different pretreatment drying technologies (biodrying and heat drying). The results indicate that biodrying combined with incineration generated approximately half of the GHG emissions compared to heat drying followed by incineration. Accordingly, biodrying may represent a more environment-friendly sludge pretreatment prior to incineration.

Enhancement of anaerobic digestibility of waste activated sludge using photo-Fenton pretreatment.

PubMed

Heng, Gan Chin; Isa, Mohamed Hasnain; Lim, Jun-Wei; Ho, Yeek-Chia; Zinatizadeh, Ali Akbar Lorestani

2017-12-01

Biological treatments, such as activated sludge process, are common methods to treat municipal and industrial wastewaters. However, they produce huge amounts of waste activated sludge (WAS). The excess sludge treatment and disposal are a challenge for wastewater treatment plants due to economic, environmental, and regulatory factors. In this study, photo-Fenton pretreatment (oxidation using hydrogen peroxide and iron catalyst aided with UV light) was optimized using response surface methodology (RSM) and central composite design (CCD) to determine the effects of three operating parameters (H 2 O 2 dosage, H 2 O 2 /Fe 2+ molar ratio, and irradiation time) on disintegration and dewaterability of WAS. MLVSS removal, capillary suction time (CST) reduction, sCOD, and EPS were obtained as 70%, 25%, 12,000 mg/L, and 500 mg/L, respectively, at the optimal conditions, i.e., 725 g H 2 O 2 /kg TS, H 2 O 2 /Fe 2+ molar ratio 80, and irradiation time 40 min. Two batch-fed completely mixed mesophilic anaerobic digesters were then operated at 15-day solid retention time (SRT) and 37 ± 0.5 °C to compare the digestibility of untreated and photo-Fenton pretreated sludge in terms of volatile solids (VS) reduction, COD removal, and biogas production at steady-state operations. Photo-Fenton pretreatment followed by anaerobic digestion of WAS was very effective and yielded 75.7% total VS reduction, 81.5% COD removal, and 0.29-0.31 m 3 /kg VS fed ·d biogas production rate, compared to 40.7% total VS solid reduction, 54.7% COD removal, and 0.12-0.17 m 3 /kg VS fed ·d biogas production rate for control. Thus, photo-Fenton can be a useful pretreatment step in sludge management.

Preparation of biochar from sewage sludge

NASA Astrophysics Data System (ADS)

Nieto, Aurora; María Méndez, Ana; Gascó, Gabriel

2013-04-01

Biomass waste materials appropriate for biochar production include crop residues (both field residues and processing residues such as nut shells, fruit pits, bagasse, etc), as well as yard, food and forestry wastes, and animal manures. Biochar can and should be made from biomass waste materials and must not contain unacceptable levels of toxins such as heavy metals which can be found in sewage sludge and industrial or landfill waste. Making biochar from biomass waste materials should create no competition for land with any other land use option—such as food production or leaving the land in its pristine state. Large amounts of agricultural, municipal and forestry biomass are currently burned or left to decompose and release CO2 and methane back into the atmosphere. They also can pollute local ground and surface waters—a large issue for livestock wastes. Using these materials to make biochar not only removes them from a pollution cycle, but biochar can be obtained as a by-product of producing energy from this biomass. Sewage sludge is a by-product from wastewater treatment plants, and contains significant amounts of heavy metals, organic toxins and pathogenic microorganisms, which are considered to be harmful to the environment and all living organisms. Agricultural use, land filling and incineration are commonly used as disposal methods. It was, however, reported that sewage sludge applications in agriculture gives rise to an accumulation of harmful components (heavy metals and organic compounds) in soil. For this reason, pyrolysis can be considered as a promising technique to treat the sewage sludge including the production of fuels. The objective of this work is to study the advantages of the biochar prepared from sewage sludge.

A novel conditioning process for enhancing dewaterability of waste activated sludge by combination of zero-valent iron and persulfate.

PubMed

Zhou, Xu; Wang, Qilin; Jiang, Guangming; Liu, Peng; Yuan, Zhiguo

2015-06-01

Improvement of sludge dewaterability is crucial for reducing the costs of sludge disposal in wastewater treatment plants. This study presents a novel conditioning method for improving waste activated sludge dewaterability by combination of persulfate and zero-valent iron. The combination of zero-valent iron (0-30g/L) and persulfate (0-6g/L) under neutral pH substantially enhanced the sludge dewaterability due to the advanced oxidization reactions. The highest enhancement of sludge dewaterability was achieved at 4g persulfate/L and 15g zero-valent iron/L, with which the capillary suction time was reduced by over 50%. The release of soluble chemical oxygen demand during the conditioning process implied the decomposition of sludge structure and microorganisms, which facilitated the improvement of dewaterability due to the release of bound water that was included in sludge structure and microorganism. Economic analysis showed that the proposed conditioning process with persulfate and ZVI is more economically favorable for improving WAS dewaterability than classical Fenton reagent. Copyright © 2015 Elsevier Ltd. All rights reserved.

Leachates from solid wastes: chemical and eco(geno)toxicological differences between leachates obtained from fresh and stabilized industrial organic sludge.

PubMed

Chiochetta, Claudete G; Goetten, Luís C; Almeida, Sônia M; Quaranta, Gaetana; Cotelle, Sylvie; Radetski, Claudemir M

2014-01-01

The chemical and ecotoxicological characteristics of fresh and stabilized industrial organic sludge leachates were compared to obtain information regarding how the stabilization process can influence the ecotoxic potential of this industrial waste, which could be used for the amendment of degraded soil. Physicochemical analysis of the sludge leachates, as well as a battery of eco(geno)toxicity tests on bacteria, algae, daphnids, and higher plants (including Vicia faba genotoxicity test) and the determination of hydrolytic enzyme activity, was performed according to standard methods. The chemical comparison of the two types of leachate showed that the samples obtained from stabilized sludge had a lower organic content and higher metal content than leachates of the fresh sludge. The eco(geno)toxicological results obtained with aquatic organisms showed that the stabilized sludge leachate was more toxic than the fresh sludge leachate, both originating from the same industrial organic sludge sample. Nevertheless, phytotoxicity tests carried out with a reference peat soil irrigated with stabilized sludge leachate showed the same toxicity as the fresh sludge leachate. In the case of the industrial solid organic sludge studied, stabilization through a biodegradation process promoted a higher metal mobility/bioavailability/eco(geno)toxicity in the stabilized sludge leachate compared to the fresh sludge leachate.

Influences of Extracellular Polymeric Substances on the Dewaterability of Sewage Sludge during Bioleaching

PubMed Central

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. PMID:25050971

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

PubMed

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.

From agricultural use of sewage sludge to nutrient extraction: A soil science outlook.

PubMed

Kirchmann, Holger; Börjesson, Gunnar; Kätterer, Thomas; Cohen, Yariv

2017-03-01

The composition of municipal wastewater and sewage sludge reflects the use and proliferation of elements and contaminants within society. In Sweden, official statistics show that concentrations of toxic metals in municipal sewage sludge have steadily decreased, by up to 90 %, since the 1970s, due to environmental programmes and statutory limits on metals in sludge and soil. Results from long-term field experiments show that reduced metal pollution during repeated sewage sludge application has reversed negative trends in soil biology. Despite this Swedish success story, organic waste recycling from Swedish towns and cities to arable land is still limited to only about 20 % of the total amount produced. Resistance among industries and consumers to products grown on land treated with sewage sludge may not always be scientifically grounded; however, there are rational obstacles to application of sewage sludge to land based on its inherent properties rather than its content of pollutants. We argue that application of urban organic wastes to soil is an efficient form of recycling for small municipalities, but that organic waste treatment from large cities requires other solutions. The large volumes of sewage sludge collected in towns and cities are not equitably distributed back to arable land because of the following: (i) The high water and low nutrient content in sewage sludge make long-distance transportation too expensive; and (ii) the low plant availability of nutrients in sewage sludge results in small yield increases even after many years of repeated sludge addition. Therefore, nutrient extraction from urban wastes instead of direct organic waste recycling is a possible way forward. The trend for increased combustion of urban wastes will make ash a key waste type in future. Combustion not only concentrates the nutrients in the ash but also leads to metal enrichment; hence, direct application of the ash to land is most often not possible. However, inorganic fertiliser (e.g. mono-ammonium phosphate fertiliser, MAP) can be produced from metal-contaminated sewage sludge ash in a process whereby the metals are removed. We argue that the view on organic waste recycling needs to be diversified in order to improve the urban-rural nutrient cycle, since only recycling urban organic wastes directly is not a viable option to close the urban-rural nutrient cycle. Recovery and recycling of nutrients from organic wastes are a possible solution. When organic waste recycling is complemented by nutrient extraction, some nutrient loops within society can be closed, enabling more sustainable agricultural production in future.

Upgrading of a small overloaded activated sludge plant using a MBBR system.

PubMed

Andreottola, G; Foladori, P; Gatti, G; Nardelli, P; Pettena, M; Ragazzi, M

2003-01-01

The aim of this research was the application of a biofilm system for the upgrading of a full-scale overloaded activated sludge MWWTP using the MBBR (Moving Bed Biofilm Reactor) technology. The choice of this fixed biomass system appeared appropriate because it offers several advantages including good potential in nitrification process, easiness of management and above all, the possibility to use the existing tank with very few modifications. MBBR system counts only few full-scale plants in Italy at the moment, thus a pilot-scale experimentation was preliminarily carried out. The acquired parameters were used for the fullscale MWWTP upgrading. The upgrading of the activated sludge reactor in the MBBR system has given (1) a relevant increase in the flowrate treated up to 60%; (2) a good efficiency in organic carbon removal and nitrification, equal to 88% and 90% respectively, with HRTs of 5.5-7 h; (3) the overcoming of the hydraulic overload of the secondary settler, applying a lamellar settler. It was observed a good correlation between the results obtained at pilot-scale and those observed in the full-scale plant.

Effects and fate of TiO2 nanoparticles in the anaerobic treatment of wastewater and waste sludge.

PubMed

Cervantes-Avilés, Pabel; Ida, Junichi; Toda, Tatsuki; Cuevas-Rodríguez, Germán

2018-05-29

The increasing use of TiO 2 nanoparticles (NPs) in customer products has also increased the concerns about their effects in the environment. Anaerobic digestion is a process probably exposed to high concentrations of TiO 2 NPs due to its application for wastewater and waste sludge treatment. In this work, it was studied the anaerobic digestion performance and the extracellular polymeric substances (EPS) production in presence of TiO 2 NPs, as well as the fate of TiO 2 NPs in anaerobic reactors. Results showed that methane production enhanced an average of 14.9% in presence TiO 2 NPs, which is considered a positive effect. A strong affinity between TiO 2 NPs and EPS was found, especially for proteins (PRO) and polysaccharides (PS) in the loosely and tightly bound EPS layers of microorganisms (LB-EPS and TB-EPS). Ti quantification indicated that 92% of the TiO 2 NPs are removed by anaerobic sludge, while 8% remain in the treated effluent. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems.

PubMed

Luostarinen, Sari; Sanders, Wendy; Kujawa-Roeleveld, Katarzyna; Zeeman, Grietje

2007-03-01

The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of COD(dis) was at first negative, but improved as the sludge adapted to low temperature. The UASB-septic tank alone did not comply with Finnish or Dutch treatment requirements and should therefore be considered mainly as a pre-treatment method. However, measuring the requirements as mgCOD l(-1) may not always be the best method, as the volume of the effluent discharged is also an important factor in the final amount of COD entering the receiving water bodies.

Dynamic control of nutrient-removal from industrial wastewater in a sequencing batch reactor, using common and low-cost online sensors.

PubMed

Dries, Jan

2016-01-01

On-line control of the biological treatment process is an innovative tool to cope with variable concentrations of chemical oxygen demand and nutrients in industrial wastewater. In the present study we implemented a simple dynamic control strategy for nutrient-removal in a sequencing batch reactor (SBR) treating variable tank truck cleaning wastewater. The control system was based on derived signals from two low-cost and robust sensors that are very common in activated sludge plants, i.e. oxidation reduction potential (ORP) and dissolved oxygen. The amount of wastewater fed during anoxic filling phases, and the number of filling phases in the SBR cycle, were determined by the appearance of the 'nitrate knee' in the profile of the ORP. The phase length of the subsequent aerobic phases was controlled by the oxygen uptake rate measured online in the reactor. As a result, the sludge loading rate (F/M ratio), the volume exchange rate and the SBR cycle length adapted dynamically to the activity of the activated sludge and the actual characteristics of the wastewater, without affecting the final effluent quality.

Soil-transmitted helminth infections associated with wastewater and sludge reuse: A review of current evidence.

PubMed

Amoah, Isaac Dennis; Adegoke, Anthony Ayodeji; Stenström, Thor Axel

2018-05-19

To review current evidence on infections related to the concentration of soil-transmitted helminth (STH) eggs in wastewater, sludge and vegetables irrigated with wastewater or grown on sludge-amended soils. Search of Web of Science, Science Direct, PubMed and Google Scholar databases for publications reporting on STH egg concentration in wastewater, sludge and vegetables and for epidemiological studies on wastewater/sludge reuse and STH infections. STH egg concentrations were variable but high in wastewater and sludge especially in developing countries. They ranged from 6 to 16,000 eggs/L in wastewater and from 0 to 23,000 eggs/g in sludge and far exceed limits set in the WHO guideline for wastewater/sludge reuse. Numbers of STH eggs on vegetables ranged from 0 to 100 eggs/g. The concentration of STH eggs in wastewater, sludge and vegetables therefore relates to risks of infection through different exposure routes. Epidemiological evidence reveals an increased prevalence of STH infections associated with direct exposure to wastewater or sludge (farmers) and consumption of vegetables grown on soil treated with it. This calls for increased efforts to reduce the adverse health impact of wastewater and sludge reuse in line with the WHO multi-barrier approach. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Stabilization of waste-activated sludge through the anoxic-aerobic digestion process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, S.; Fujita, M.; Terai, K.

1982-08-01

During the aerobic digestion process, the nitrogen which had been embedded in the activated sludge is solubilized to form ammoniacal and nitric nitrogen which are in turn transferred to the liquor and cause the increase of nitrogen loading in the sewage treatment plant. In this study, the anoxic-aerobic sludge digestion system which is a modified form of the conventional aerobic sludge digestion is made up of aerobic and anoxic tanks and are designed to remove both the volatile suspended solids and the total nitrogen (TN) simultaneously. The removal efficiencies of both VSS and TN were investigated by feeding waste-activated sludgemore » continuously and semicontinuously. The maximum percent reduction of both VSS and TN was achieved at a Q /SUB r/ /Q /SUB s/ ratio of 2 in the continuous process. The semicontinuous process was used to improve the nitrogen removal efficiency further. In the semicontinuous process, the VSS reduction efficiency as well as the nitrogen removal efficiency increased remarkably under a constant Q /SUB r/ /Q /SUB s/ ratio of 2. This process also achieved a VSS reduction efficiency higher than the aerobic digestion process (control). It was suggested that the additional anoxic tank enhanced the sludge digestion. Furthermore, the anoxic-aerobic digestion system can be applied to other treatment media like the primary sludge, industrial sludge, animal manure, etc.« less

Relative contribution of ammonia oxidizing bacteria and other members of nitrifying activated sludge communities to micropollutant biotransformation.

PubMed

Men, Yujie; Achermann, Stefan; Helbling, Damian E; Johnson, David R; Fenner, Kathrin

2017-02-01

Improved micropollutant (MP) biotransformation during biological wastewater treatment has been associated with high ammonia oxidation activities, suggesting co-metabolic biotransformation by ammonia oxidizing bacteria as an underlying mechanism. The goal of this study was to clarify the contribution of ammonia oxidizing bacteria to increased MP degradation in nitrifying activated sludge (NAS) communities using a series of inhibition experiments. To this end, we treated a NAS community with two different ammonia oxidation inhibitors, namely octyne (OCT), a mechanistic inhibitor that covalently binds to ammonia monooxygenases, and allylthiourea (ATU), a copper chelator that depletes copper ions from the active center of ammonia monooxygenases. We investigated the biotransformation of 79 structurally different MPs by the inhibitor-treated and untreated sludge communities. Fifty-five compounds exhibited over 20% removal in the untreated control after a 46 h-incubation. Of these, 31 compounds were significantly inhibited by either ATU and/or OCT. For 17 of the 31 MPs, the inhibition by ATU at 46 h was substantially higher than by OCT despite the full inhibition of ammonia oxidation by both inhibitors. This was particularly the case for almost all thioether and phenylurea compounds tested, suggesting that in nitrifying activated sludge communities, ATU does not exclusively act as an inhibitor of bacterial ammonia oxidation. Rather, ATU also inhibited enzymes contributing to MP biotransformation but not to bulk ammonia oxidation. Thus, inhibition studies with ATU tend to overestimate the contribution of ammonia-oxidizing bacteria to MP biotransformation in nitrifying activated sludge communities. Biolog tests revealed only minor effects of ATU on the heterotrophic respiration of common organic substrates by the sludge community, suggesting that ATU did not affect enzymes that were essential in energy conservation and central metabolism of heterotrophs. By comparing ATU- and OCT-treated samples, as well as before and after ammonia oxidation was recovered in OCT-treated samples, we were able to demonstrate that ammonia-oxidizing bacteria were highly involved in the biotransformation of four compounds: asulam, clomazone, monuron and trimethoprim. Copyright © 2016 Elsevier Ltd. All rights reserved.

Decontamination of sludge by the METIX-AC process. Part II: effects on maize growth and bioaccumulation of metals.

PubMed

Barraoui, Driss; Labrecque, Michel; Blais, Jean-François

2008-03-01

Given the fact that, according to our knowledge, no study has compared the agro-environmental use of decontaminated with non-decontaminated sludge, a greenhouse experiment was carried out to test the growth of maize (Zea mays L., G-4011 Hybrid) and bioaccumulation of metals in the presence of four different sludges (MUC, QUC, BEC and DAI), before and after their decontamination by a novel process (METIX-AC). Data showed that decontaminated sludge ameliorated plant growth and biomass production, and decreased bioaccumulation of metals, more than control soil, inorganic chemical fertilization, or conventional non-decontaminated sludge. Since chemicals used by the METIX-AC process contained S and Fe, decontaminated sludge introduced large amounts of these elements, while the overall presence of metals was reduced. Often, sludge dose also affected maize growth and bioaccumulation of metals. Overall, no toxicity to plants was noticed and bioaccumulation and transfer of many metals remained below the limits reported in the literature.

Gaseous emissions from sewage sludge combustion in a moving bed combustor.

PubMed

Batistella, Luciane; Silva, Valdemar; Suzin, Renato C; Virmond, Elaine; Althoff, Chrtistine A; Moreira, Regina F P M; José, Humberto J

2015-12-01

Substantial increase in sewage sludge generation in recent years requires suitable destination for this residue. This study evaluated the gaseous emissions generated during combustion of an aerobic sewage sludge in a pilot scale moving bed reactor. To utilize the heat generated during combustion, the exhaust gas was applied to the raw sludge drying process. The gaseous emissions were analyzed both after the combustion and drying steps. The results of the sewage sludge characterization showed the energy potential of this residue (LHV equal to 14.5 MJ kg(-1), db) and low concentration of metals, polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The concentration of CO, NOx, BTEX (benzene, toluene, ethylbenzene and xylenes) emitted from the sludge combustion process were lower than the legal limits. The overall sludge combustion and drying process showed low emissions of PCDD/PCDF (0.42 ng I-TEQ N m(-3)). BTEX and PAH emissions were not detected. Even with the high nitrogen concentration in the raw feed (5.88% db), the sludge combustion process presented NOx emissions below the legal limit, which results from the combination of appropriate feed rate (A/F ratio), excess air, and mainly the low temperature kept inside the combustion chamber. It was found that the level of CO emissions from the overall sludge process depends on the dryer operating conditions, such as the oxygen content and the drying temperature, which have to be controlled throughout the process in order to achieve low CO levels. The aerobic sewage sludge combustion process generated high SO2 concentration due to the high sulfur content (0.67 wt%, db) and low calcium concentration (22.99 g kg(-1)) found in the sludge. The high concentration of SO2 in the flue gas (4776.77 mg N m(-3)) is the main factor inhibiting PCDD/PCDF formation. Further changes are needed in the pilot plant scheme to reduce SO2 and particulate matter emissions, such as the installation of exhaust gas-cleaning systems. According to previous studies, the efficient operation of such cleaning systems is also effective for metals emission control, which makes the combustion of sewage sludge a feasible treatment method from both energetic and environmental perspectives. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Emissions of greenhouse gas and ammonia from the full process of sewage sludge composting and land application of compost].

PubMed

Zhong, Jia; Wei, Yuan-Song; Zhao, Zhen-Feng; Ying, Mei-Juan; Zhou, Guo-Sheng; Xiong, Jian-Jun; Liu, Pei-Cai; Ge, Zhen; Ding, Gang-Qiang

2013-11-01

There is a great uncertainty of greenhouse gas (GHG) reduction and nitrogen conservation from the full process of sludge composting and land application of compost in China due to the lack of emission data of GHG such as N2O and CH4 and ammonia (NH3). The purpose of this study is to get emission characteristics of GHGs and NH3 from the full process with on-site observation. Results showed that the total GHG emission factor from full process of the turning windrow (TW) system (eCO2/dry sludge, 196.21 kg x t(-1)) was 1.61 times higher of that from the ATP system. Among the full process, N2O was mostly from the land application of compost, whereas CH4 mainly resulted from the sludge composting. In the sludge composting of ATP, the GHG emission equivalence of the ATP (eCO2/dry sludge, 12.47 kg x t(-1) was much lower than that of the TW (eCO2/dry sludge, 86.84 kg x t(-1)). The total NH3 emission factor of the TW (NH3/dry sludge, 6.86 kg x t(-1)) was slightly higher than that of the ATP (NH3/dry sludge, 6.63 kg x t(-1)). NH3 was the major contributor of nitrogen loss in the full process. During the composting, the nitrogen loss as NH3 from both TW and ATP was nearly the same as 30% of TN loss from raw materials, and the N and C loss caused by N2O and CH4 were negligible. These results clearly showed that the ATP was a kind of environmentally friendly composting technology.

Comprehensive characterisation of sewage sludge for thermochemical conversion processes - Based on Singapore survey.

PubMed

Chan, Wei Ping; Wang, Jing-Yuan

2016-08-01

Recently, sludge attracted great interest as a potential feedstock in thermochemical conversion processes. However, compositions and thermal degradation behaviours of sludge were highly complex and distinctive compared to other traditional feedstock led to a need of fundamental research on sludge. Comprehensive characterisation of sludge specifically for thermochemical conversion was carried out for all existing Water Reclamation Plants in Singapore. In total, 14 sludge samples collected based on the type, plant, and batch categorisation. Existing characterisation methods for physical and chemical properties were analysed and reviewed using the collected samples. Qualitative similarities and quantitative variations of different sludge samples were identified and discussed. Oxidation of inorganic in sludge during ash forming analysis found to be causing significant deviations on proximate and ultimate analysis. Therefore, alternative parameters and comparison basis including Fixed Residues (FR), Inorganic Matters (IM) and Total Inorganics (TI) were proposed for better understanding on the thermochemical characteristics of sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Drying characteristics and apparent change of sludge granules during drying].

PubMed

Ma, Xue-Wen; Weng, Huan-Xin; Zhang, Jin-Jun

2011-08-01

Three different weight grades of sludge granules (2.5, 5, 10 g) were dried at constant temperature of 100, 200, 300, 400 and 500 degrees C, respectively. Then characteristics of weight loss and change of apparent form during sludge drying were analyzed. Results showed that there were three stages during sludge drying at 100-200 degrees C: acceleration phase, constant-rate phase, and falling-rate phase. At 300-500 degrees C, there were no constant-rate phase, but due to lots of cracks generated at sludge surface, average drying rates were still high. There was a quadratic nonlinear relationship between average drying rate and drying temperature. At 100-200 degrees C, drying processes of different weight grade sludge granules were similar. At 300-500 degrees C, drying processes of same weight grade of sludge granules were similar. Little organic matter decomposed till sludge burning at 100-300 degrees C, while some organic matter began to decompose at the beginning of sludge drying at 400-500 degrees C.

Adapting SimpleTreat for simulating behaviour of chemical substances during industrial sewage treatment.

PubMed

Struijs, J; van de Meent, D; Schowanek, D; Buchholz, H; Patoux, R; Wolf, T; Austin, T; Tolls, J; van Leeuwen, K; Galay-Burgos, M

2016-09-01

The multimedia model SimpleTreat, evaluates the distribution and elimination of chemicals by municipal sewage treatment plants (STP). It is applied in the framework of REACH (Registration, Evaluation, Authorization and Restriction of Chemicals). This article describes an adaptation of this model for application to industrial sewage treatment plants (I-STP). The intended use of this re-parametrized model is focused on risk assessment during manufacture and subsequent uses of chemicals, also in the framework of REACH. The results of an inquiry on the operational characteristics of industrial sewage treatment installations were used to re-parameterize the model. It appeared that one property of industrial sewage, i.e. Biological Oxygen Demand (BOD) in combination with one parameter of the activated sludge process, the hydraulic retention time (HRT) is satisfactory to define treatment of industrial wastewater by means of the activated sludge process. The adapted model was compared to the original municipal version, SimpleTreat 4.0, by means of a sensitivity analysis. The consistency of the model output was assessed by computing the emission to water from an I-STP of a set of fictitious chemicals. This set of chemicals exhibit a range of physico-chemical and biodegradability properties occurring in industrial wastewater. Predicted removal rates of a chemical from raw sewage are higher in industrial than in municipal STPs. The latter have typically shorter hydraulic retention times with diminished opportunity for elimination of the chemical due to volatilization and biodegradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

Yamaguchi, T; Yao, Y; Kihara, Y

2006-01-01

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

Alkaline treatment of high-solids sludge and its application to anaerobic digestion.

PubMed

Li, Chenchen; Li, Huan; Zhang, Yuyao

2015-01-01

High-solids anaerobic digestion is a promising new process for sludge reduction and bioenergy recovery, requiring smaller digestion tanks and less energy for heating, but a longer digestion time, than traditional low-solids anaerobic digestion. To accelerate this process, alkaline sludge disintegration was tested as a pretreatment method for anaerobic digestion of high-solids sludge. The results showed that alkaline treatment effectively disintegrated both low-solids sludge and high-solids sludge, and treatment duration of 30 min was the most efficient. The relation between sludge disintegration degree and NaOH dose can be described by a transmutative power function model. At NaOH dose lower than 0.2 mol/L, sludge disintegration degree remained virtually unchanged when sludge total solids (TS) content increased from 2.0 to 11.0%, and decreased only slightly when sludge TS increased to 14.2%. Although high-solids sludge required a slightly higher molarity of NaOH to reach the same disintegration level of low-solids sludge, the required mass of NaOH actually decreased due to sludge thickening. From the view of NaOH consumption, sludge TS of 8-12% and a NaOH dose of 0.05 mol/L were optimum conditions for alkaline pretreatment, which resulted in a slight increase in accumulative biogas yield, but a decrease by 24-29% in digestion time during the subsequent anaerobic digestion.

Advanced oxidation process using hydrogen peroxide/microwave system for solubilization of phosphate.

PubMed

Liao, Ping Huang; Wong, Wayne T; Lo, Kwang Victor

2005-01-01

An advanced oxidation process (AOP) combining hydrogen peroxide and microwave heating was used for the solubilization of phosphate from secondary municipal sludge from an enhanced biological phosphorus removal process. The microwave irradiation is used as a generator agent of oxidizing radicals as well as a heating source in the process. This AOP process could facilitate the release of a large amount of the sludge-bound phosphorus from the sewage sludge. More than 84% of the total phosphorous could be released at a microwave heating time of 5 min at 170 degrees C. This innovative process has the potential of being applied to simple sludge treatment processes in domestic wastewater treatment and to the recovery of phosphorus from the wastewater.

Enhancement of the sludge disintegration and nutrients release by a treatment with potassium ferrate combined with an ultrasonic process.

PubMed

Li, Wei; Yu, Najiaowa; Liu, Qian; Li, Yiran; Ren, Nanqi; Xing, Defeng

2018-09-01

Sludge disintegration by ultrasound is a promising sludge treatment method. In order to enhance the efficiency of the sludge reduction and hydrolysis, potassium ferrate (K 2 FeO 4 ) (PF) was used. A novel method was developed to improve the sludge disintegration-sludge pretreatment by using PF in combination with an ultrasonic treatment (PF + ULT). After a short-term PF + ULT treatment, 17.23% of the volatile suspended solids (VSS) were reduced after a 900-min reaction time, which is 61.3% higher than the VSS reduction for the raw sludge. The supernatant soluble chemical oxygen demand (SCOD), total nitrogen (TN), volatile fatty acids (VFAs), soluble protein and polysaccharides increased by 522.5%, 1029.4%, 878.4%, 2996.6% and 801.9%, respectively. The constituent parts of the dissolved organic matter of the sludge products were released efficiently, which demonstrated the positive effect caused by the PF + ULT. The enhanced sludge disintegration process further alleviates environmental risk and offers a more efficient and convenient method for utilizing sludge. Copyright © 2018 Elsevier B.V. All rights reserved.

Comprehensive monitoring and management of a long-term thermophilic CSTR treating coffee grounds, coffee liquid, milk waste, and municipal sludge.

PubMed

Shofie, Mohammad; Qiao, Wei; Li, Qian; Takayanagi, Kazuyuki; Li, Yu-You

2015-09-01

The CSTR process has previously not been successfully applied to treat coffee residues under thermophilic temperature and long term operation. In this experiment, the CSTR was fed with mixture substrate (TS ∼ 70 g/L) of coffee grounds, coffee wastewater, milk waste and municipal sludge and it was operated under 55 °C for 225 days. A steady state was achieved under HRT 30 days and OLR 4.0 kg-COD/m(3)/d. However, there was an 35 days inhibition with VFA accumulation (propionic acid 700-1900 mg/L) when doubling the OLR by shortening HRT to 15 days. But, an addition of microelements and sulfate (0.5 g/L) in feedstock increased reactor resilience and stability under high loading rate and propionic acid stress. Continuous monitoring of hydrogen in biogas indicated the imbalance of acetogenesis. The effectiveness of comprehensive parameters (total VFA, propionic acid, IA/PA, IA/TA and CH4 content) was proved to manage the thermophilic system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biogas recirculation for simultaneous calcium removal and biogas purification within an expanded granular sludge bed system treating leachate.

PubMed

Luo, Jinghuan; Lu, Xueqin; Liu, Jianyong; Qian, Guangren; Lu, Yongsheng

2014-12-01

Biogas, generated from an expanded granular sludge bed (EGSB) reactor treating municipal solid waste (MSW) leachate, was recirculated for calcium removal from the leachate via a carbonation process with simultaneous biogas purification. Batch trials were performed to optimize the solution pH and imported biogas (CO2) for CaCO3 precipitation. With applicable pH of 10-11 obtained, continuous trials achieved final calcium concentrations of 181-375 mg/L (removal efficiencies≈92.8-96.5%) in the leachate and methane contents of 87.1-91.4% (purification efficiencies≈65.4-82.2%) in the biogas. Calcium-balance study indicates that 23-986 mg Ca/d was released from the bio-system under the carbonized condition where CaCO3 precipitating was moved outside the bioreactor, whereas 7918-9517 mg Ca/d was trapped into the system for the controlled one. These findings demonstrate that carbonation removal of calcium by biogas recirculation could be a promising alternative to pretreat calcium-rich MSW leachate and synergistically to improve methane content. Copyright © 2014 Elsevier Ltd. All rights reserved.

A pilot-scale microwave technology for sludge sanitization and drying.

PubMed

Mawioo, Peter M; Garcia, Hector A; Hooijmans, Christine M; Velkushanova, Konstantina; Simonič, Marjana; Mijatović, Ivan; Brdjanovic, Damir

2017-12-01

Large volumes of sludge are produced from onsite sanitation systems in densely populated areas (e.g. slums and emergency settlements) and wastewater treatment facilities that contain high amounts of pathogens. There is a need for technological options which can effectively treat the rapidly accumulating sludge under these conditions. This study explored a pilot-scale microwave (MW) based reactor as a possible alternative for rapid sludge treatment. The reactor performance was examined by conducting a series of batch tests using centrifuged waste activated sludge (C-WAS), non-centrifuged waste activated sludge (WAS), faecal sludge (FS), and septic tank sludge (SS). Four kilograms of each sludge type were subjected to MW treatment at a power of 3.4kW for various time durations ranging from 30 to 240min. During the treatment the temperature change, bacteria inactivation (E. coli, coliforms, Staphylococcus aureus, and enterococcus faecalis) and sludge weight/volume reduction were measured. Calorific values (CV) of the dried sludge and the nutrient content (total nitrogen (TN) and total phosphorus (TP)) in both the dried sludge and the condensate were also determined. It was found that MW treatment was successful to achieve a complete bacterial inactivation and a sludge weight/volume reduction above 60%. Besides, the dried sludge and condensate had high energy (≥16MJ/kg) and nutrient contents (solids; TN≥28mg/g TS and TP≥15mg/g TS; condensate TN≥49mg/L TS and TP≥0.2mg/L), having the potential to be used as biofuel, soil conditioner, fertilizer, etc. The MW reactor can be applied for the rapid treatment of sludge in areas such as slums and emergency settlements. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic–Anoxic–Aerobic Activated Sludge System

PubMed Central

Zeng, Qingling; Li, Yongmei; Yang, Shijia

2013-01-01

Abstract Estrogen in wastewater are responsible for a significant part of the endocrine-disrupting effects observed in the aquatic environment. The effect of sludge retention time (SRT) on the removal and fate of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in an anaerobic–anoxic–oxic activated sludge system designed for nutrient removal was investigated by laboratory-scale experiments using synthetic wastewater. With a hydraulic retention time of 8 h, when SRT ranged 10–25 days, E2 was almost completely removed from water, and EE2 removal efficiency was 65%–81%. Both estrogens were easily sorbed onto activated sludge. Distribution coefficients (Kd) of estrogens on anaerobic sludge were greater than those on anoxic and aerobic sludges. Mass balance calculation indicated that 99% of influent E2 was degraded by the activated sludge process, and 1% remained in excess sludge; of influent EE2, 62.0%–80.1% was biodegraded; 18.9%–34.7% was released in effluent; and 0.88%–3.31% remained in excess sludge. Optimal SRT was 20 days for both estrogen and nutrient removal. E2 was almost completely degraded, and EE2 was only partly degraded in the activated sludge process. Residual estrogen on excess sludge must be considered in the sludge treatment and disposal processes. The originality of the work is that removal of nutrients and estrogens were linked, and optimal SRT for both estrogen and nutrient removal in an enhanced biological phosphorus removal system was determined. This has an important implication for the design and operation of full-scale wastewater treatment plants. PMID:23633892

Surplus activated sludge dewatering in pilot-scale sludge drying reed beds.

PubMed

Stefanakis, A I; Akratos, C S; Melidis, P; Tsihrintzis, V A

2009-12-30

A pilot-scale experiment on dewatering of surplus activated sludge (SAS) is presented, where two pilot-scale vertical flow, sludge drying reed beds (SDRBs), planted with Phragmites australis are used. The bottom of the beds is filled with cobbles, connected to the atmosphere through perforated PVC ventilation tubes, in order to achieve oxygen diffusion through the overlying porous medium that is colonized by roots and an abundant nitrifying biomass. Two layers of gravel, of decreasing size from bottom to top, make the drainage layer where the reeds are planted. The two beds were fed according to the following cycle: one week feeding with SAS at rates one 30 kg/m(2)/year and the other 75 kg/m(2)/year, and resting for three weeks. The results show that planted SDRBs can effectively dewater SAS from domestic sewage, the produced residual sludge presents a high dry weight content, the degree of volume reduction depends upon the initial SAS concentration and can be of the order of 90%, and decomposition of organic matter and high levels of mineralization can be achieved. Furthermore, the percolating water is not septic. The fertilizer value of the treated SAS, which contains no added chemicals, is comparable to that of SAS treated by other methods.

Comparison of modelling accuracy with and without exploiting automated optical monitoring information in predicting the treated wastewater quality.

PubMed

Tomperi, Jani; Leiviskä, Kauko

2018-06-01

Traditionally the modelling in an activated sludge process has been based on solely the process measurements, but as the interest to optically monitor wastewater samples to characterize the floc morphology has increased, in the recent years the results of image analyses have been more frequently utilized to predict the characteristics of wastewater. This study shows that the traditional process measurements or the automated optical monitoring variables by themselves are not capable of developing the best predictive models for the treated wastewater quality in a full-scale wastewater treatment plant, but utilizing these variables together the optimal models, which show the level and changes in the treated wastewater quality, are achieved. By this early warning, process operation can be optimized to avoid environmental damages and economic losses. The study also shows that specific optical monitoring variables are important in modelling a certain quality parameter, regardless of the other input variables available.

Transferring of components and energy output in industrial sewage sludge disposal by thermal pretreatment and two-phase anaerobic process.

PubMed

Yang, Xiaoyi; Wang, Xin; Wang, Lei

2010-04-01

For a better sewage sludge disposal and more efficient energy reclamation, transforming of components and energy in sludge by thermal and WAO pretreatment followed by two-phase anaerobic UASB process were studied in the pilot scale. Biogas outputs and the qualities and quantities of the effluent and solid residue were compared with a traditional anaerobic sludge digestion. Sludge components, including carbon, nitrogen, phosphorus, sulphur, were observed and mass balances were discussed throughout the process. The input and output energy balance was also studied. Results showed different trait to compare with biogas outputs in terms of COD added and raw sludge added. Pretreatment improved the transformation of carbon substances into biogas production with higher carbon removal and higher VSS removal. Comparing the energy obtained from biogas production with energy inputs required for pretreatment, energy output in the whole process decreased with higher pretreatment temperature. Copyright 2009 Elsevier Ltd. All rights reserved.

Toluene in sewage and sludge in wastewater treatment plants.

PubMed

Mrowiec, Bozena

2014-01-01

Toluene is a compound that often occurs in municipal wastewater ranging from detectable levels up to 237 μg/L. Before the year 2000, the presence of the aromatic hydrocarbons was assigned only to external sources. The Enhanced Biological Nutrients Removal Processes (EBNRP) work according to many different schemes and technologies. For high-efficiency biological denitrification and dephosphatation processes, the presence of volatile fatty acids (VFAs) in sewage is required. VFAs are the main product of organic matter hydrolysis from sewage sludge. However, no attention has been given to other products of the process. It has been found that in parallel to VFA production, toluene formation occurred. The formation of toluene in municipal anaerobic sludge digestion processes was investigated. Experiments were performed on a laboratory scale using sludge from primary and secondary settling tanks of municipal treatment plants. The concentration of toluene in the digested sludge from primary settling tanks was found to be about 42,000 μg/L. The digested sludge supernatant liquor returned to the biological dephosphatation and denitrification processes for sewage enrichment can contain up to 16,500 μg/L of toluene.

Land application of treated sewage sludge: community health and environmental justice.

PubMed

Lowman, Amy; McDonald, Mary Anne; Wing, Steve; Muhammad, Naeema

2013-05-01

In the United States, most of the treated sewage sludge (biosolids) is applied to farmland as a soil amendment. Critics suggest that rules regulating sewage sludge treatment and land application may be insufficient to protect public health and the environment. Neighbors of land application sites report illness following land application events. We used qualitative research methods to evaluate health and quality of life near land application sites. We conducted in-depth interviews with neighbors of land application sites and used qualitative analytic software and team-based methods to analyze interview transcripts and identify themes. Thirty-four people in North Carolina, South Carolina, and Virginia responded to interviews. Key themes were health impacts, environmental impacts, and environmental justice. Over half of the respondents attributed physical symptoms to application events. Most noted offensive sludge odors that interfere with daily activities and opportunities to socialize with family and friends. Several questioned the fairness of disposing of urban waste in rural neighborhoods. Although a few respondents were satisfied with the responsiveness of public officials regarding sludge, many reported a lack of public notification about land application in their neighborhoods, as well as difficulty reporting concerns to public officials and influencing decisions about how the practice is conducted where they live. Community members are key witnesses of land application events and their potential impacts on health, quality of life, and the environment. Meaningful involvement of community members in decision making about land application of sewage sludge will strengthen environmental health protections.

Improving the compression dewatering of sewage sludge through bioacidification conditioning driven by Acidithiobacillus ferrooxidans: dewatering rate vs. dewatering extent.

PubMed

Lu, Yi; Zhang, Chunmei; Zheng, Guanyu; Zhou, Lixiang

2018-04-22

Prior to mechanical dewatering, sludge conditioning is indispensable to reduce the difficulty of sludge treatment and disposal. The effect of bioacidification conditioning driven by Acidithiobacillus ferrooxidans LX5 on the dewatering rate and extent of sewage sludge during compression dewatering process was investigated in this study. The results showed that the bioacidification of sludge driven by A. ferrooxidans LX5 simultaneously improved both the sludge dewatering rate and extent, which was not attained by physical/chemical conditioning approaches, including ultrasonication, microwave, freezing/thawing, or by adding the chemical conditioner cationic polyacrylamide (CPAM). During the bioacidification of sludge, the decrease in sludge pH induced the damage of sludge microbial cell structures, which enhanced the dewatering extent of sludge, and the added Fe 2+ and the subsequent bio-oxidized Fe 3+ effectively flocculated the damaged sludge flocs to improve the sludge dewatering rate. In the compression dewatering process consisting of filtration and expression stages, high removal of moisture and a short dewatering time were achieved during the filtration stage and the expression kinetics were also improved because of the high elasticity of sludge cake and the rapid creeping of the aggregates within the sludge cake. In addition, the usefulness of bioacidification driven by A. ferrooxidans LX5 in improving the compression dewatering of sewage sludge could not be attained by the chemical treatment of sludge through pH modification and Fe 3+ addition. Therefore, the bioacidification of sludge driven by A. ferrooxidans LX5 is an effective conditioning method to simultaneously improve the rate and extent of compression dewatering of sewage sludge.

Removal of Triclocarban and Triclosan during Municipal Biosolid Production

PubMed Central

Ogunyoku, Temitope A.; Young, Thomas M.

2014-01-01

The antimicrobial compounds triclosan (TCS) and triclocarban (TCC) accumulate in sludges produced during municipal wastewater treatment and persist through sludge treatment processes into finished biosolids. The objective of this research was to determine the extent to which conventional sludge processing systems such as aerobic digestion, anaerobic digestion, and lime stabilization were able to remove TCC and TCS. Sludge and biosolid samples were collected from 10 municipal wastewater treatment plants in the United States. The concentrations of TCC and TCS in sludge and biosolid samples were determined via heated solvent extraction and analysis with liquid chromatography electrospray ionization mass spectrometry. Dry weight concentrations of TCC and TCS frequently were higher in finished biosolids than in the source sludges because of sludge mass reduction during digestion. The removal of TCC and TCS in municipal biosolid processing systems was determined from the measured concentration change after correcting for reductions in solid mass during sludge treatment. Removal in the digester systems ranged from 15 – 68 % for TCC and 20 – 75 % for TCS. Increased solid retention times during sludge treatment operations were correlated with higher removals of TCC and TCS. Apparent first order degradation rates for TCC ranged from 0.015–0.08 1/d and for TCS were between 0.003–0.15 1/d. PMID:24734467

PHARMACEUTICALS AND PERSONAL CARE PRODUCTS IN BIOSOLIDS/SEWAGE SLUDGES - THE INTERFACE BETWEEN ANALYTICAL CHEMISTRY AND REGULATION

EPA Science Inventory

Modern sanitary practices result in large volumes of human waste, as well as domestic and industrial sewage, being collected and treated at common collection points, wastewater treatment plants (WWTP). In recognition of the growing use of sewage sludges as a fertilizers and as so...

Physical and chemical properties of pyrolyzed MWRDGC biosolids for utilization in sand-based turfgrass rootzones

USDA-ARS?s Scientific Manuscript database

Biosolids are several forms of treated sewage sludge that are intended for use as soil conditioners for horticultural and agricultural crops. In the U.S., biosolids may only refer to conditioned sludge that meets USEPA pollutant and pathogen requirements for land application and surface disposal. Th...

Factors affecting decay of Salmonella Birkenhead and coliphage MS2 during mesophilic anaerobic digestion and air drying of sewage sludge.

PubMed

Mondal, Tania; Rouch, Duncan A; Thurbon, Nerida; Smith, Stephen R; Deighton, Margaret A

2015-06-01

Factors affecting the decay of Salmonella Birkenhead and coliphage, as representatives of bacterial and viral pathogens, respectively, during mesophilic anaerobic digestion (MAD) and air drying treatment of anaerobically digested sewage sludge were investigated. Controlled concentrations of S. Birkenhead were inoculated into non-sterile, autoclaved, γ-irradiated and nutrient-supplemented sludge and cultures were incubated at 37 °C (MAD sludge treatment temperature) or 20 °C (summer air drying sludge treatment temperature). Nutrient limitation caused by microbial competition was the principal mechanism responsible for the decay of S. Birkenhead by MAD and during air drying of digested sludge. The effects of protease activity in sludge on MS2 coliphage decay in digested and air dried sludge were also investigated. MS2 coliphage showed a 3.0-3.5 log10 reduction during incubation with sludge-protease extracts at 37 °C for 25 h. Proteases produced by indigenous microbes in sludge potentially increase coliphage inactivation and may therefore have a significant role in the decay of enteric viruses in sewage sludge. The results help to explain the loss of viability of enteric bacteria and viral pathogens with treatment process time and contribute to fundamental understanding of the various biotic inactivation mechanisms operating in sludge treatment processes at mesophilic and ambient temperatures.

The role of sorption processes in the removal of pharmaceuticals by fungal treatment of wastewater.

PubMed

Lucas, D; Castellet-Rovira, F; Villagrasa, M; Badia-Fabregat, M; Barceló, D; Vicent, T; Caminal, G; Sarrà, M; Rodríguez-Mozaz, S

2018-01-01

The contribution of the sorption processes in the elimination of pharmaceuticals (PhACs) during the fungal treatment of wastewater has been evaluated in this work. The sorption of four PhACs (carbamazepine, diclofenac, iopromide and venlafaxine) by 6 different fungi was first evaluated in batch experiments. Concentrations of PhACs in both liquid and solid (biomass) matrices from the fungal treatment were measured. Contribution of the sorption to the total removal of pollutants ranged between 3% and 13% in relation to the initial amount. The sorption of 47 PhACs in fungi was also evaluated in a fungal treatment performed in 26days in a continuous bioreactor treating wastewater from a veterinary hospital. PhACs levels measured in the fungal biomass were similar to those detected in conventional wastewater treatment (WWTP) sludge. This may suggest the necessity of manage fungal biomass as waste in the same manner that the WWTP sludge is managed. Copyright © 2017 Elsevier B.V. All rights reserved.

Carbon capture and biogas enhancement by carbon dioxide enrichment of anaerobic digesters treating sewage sludge or food waste.

PubMed

Bajón Fernández, Y; Soares, A; Villa, R; Vale, P; Cartmell, E

2014-05-01

The increasing concentration of carbon dioxide (CO2) in the atmosphere and the stringent greenhouse gases (GHG) reduction targets, require the development of CO2 sequestration technologies applicable for the waste and wastewater sector. This study addressed the reduction of CO2 emissions and enhancement of biogas production associated with CO2 enrichment of anaerobic digesters (ADs). The benefits of CO2 enrichment were examined by injecting CO2 at 0, 0.3, 0.6 and 0.9 M fractions into batch ADs treating food waste or sewage sludge. Daily specific methane (CH4) production increased 11-16% for food waste and 96-138% for sewage sludge over the first 24h. Potential CO2 reductions of 8-34% for sewage sludge and 3-11% for food waste were estimated. The capacity of ADs to utilise additional CO2 was demonstrated, which could provide a potential solution for onsite sequestration of CO2 streams while enhancing renewable energy production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Amelioration of municipal sludge by Pistia stratiotes L.: role of antioxidant enzymes in detoxification of metals.

PubMed

Tewari, Anamika; Singh, Ragini; Singh, Naveen Kumar; Rai, U N

2008-12-01

Pistia stratiotes when exposed to mixture of municipal sludge and effluent accumulated substantial amount of metals in the fronds and roots. With the increase in the metal accumulation by the plants, a reduction in the concentration of metals was found in leachates. The treated plants showed reduced level in chlorophylls but enhanced level of carotenoids and protein. The plant showed a concomitant increase in the activities of antioxidant enzymes; superoxide dismutase, guiacol peroxidase and also an enhanced level of lipid peroxidation. The activities were more in the root tissues as compared to frond. Initially a reduced level of cysteine content in roots of sludge treated plant as compared to control was found, but with time duration it increased progressively. The level of non-protein thiols also increased gradually at all the durations in both fronds and roots. Thus, beside the reduction of metals from municipal sludge, the ability of P. stratiotes to combat metal generated damages by induced synthesis of antioxidant enzymes and other metal binding ligands shows its suitability for the phytoremediation of the waste.

Enhancement of activated sludge disintegration and dewaterability by Fenton process

NASA Astrophysics Data System (ADS)

Heng, G. C.; Isa, M. H.

2016-06-01

Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the activated sludge process. In this study, the waste activated sludge was obtained from the campus wastewater treatment plant at Universiti Teknologi PETRONAS (UTP), Malaysia. Fenton pretreatment was optimized by using the response surface methodology (RSM) to study the effects of three operating conditions including the dosage of H2O2 (g H2O2/kg TS), the molar ratio of H2O2/Fe2+ and reaction time. The optimum operating variables to achieve MLVSS removal 65%, CST reduction 28%, sCOD 11000 mg/L and EPS 500 mg/L were: 1000 g H2O2/kg TS, H2O2/Fe2+ molar ratio 70 and reaction time 45 min. Fenton process was proved to be able to enhance the sludge disintegration and dewaterability.

Removal of Plant Nutrients by Means of Aerobic Stabilization of Sludge

PubMed Central

Irgens, Roar L.; Halvorson, H. Orin

1965-01-01

In the conventional treatment of sewage, the solids are normally disposed of by anaerobic digestion. This leaves a considerable amount of plant nutrients, such as nitrogen and phosphate, as soluble compounds which will eventually find their way into the plant's final effluent, since the supernatant fluid from the digesters is normally returned to the raw sewage. In a recent investigation, we found that, if the sludges were treated by an aerobic process, a significant portion of the carbonaceous matter was oxidized to carbon dioxide and water, and the rest was assimilated into microbial protoplasm. This process tied up the available nitrogen and phosphorus so that practically none remained dissolved in the suspending liquid. The accumulated solids, consisting mostly of microbial cells, were separated very easily from the liquid, leaving a slightly colored supernatant fluid that was water-clear, free from plant nutrients, and very low in BOD and COD. The overall process was accomplished in a detention time not exceeding 20 days, in contrast to anaerobic digestion which requires from 50 to 70 days. PMID:14325277

Biological hydrogen production by anaerobic digestion of food waste and sewage sludge treated using various pretreatment technologies.

PubMed

Kim, Seungjin; Choi, Kwangkeun; Kim, Jong-Oh; Chung, Jinwook

2013-11-01

The purpose of this study was to enhance the efficiency of anaerobic co-digestion with sewage sludge using pretreatment technologies and food waste. We studied the effects of various pretreatment methods (thermal, chemical, ultrasonic, and their combination) on hydrogen production and the characteristics of volatile fatty acids (VFAs) using sewage sludge alone and a mixture of sewage sludge and food waste. The pretreatment combination of alkalization and ultrasonication performed best, effecting a high solubilization rate and high hydrogen production (13.8 mL H2/g VSSconsumed). At a food waste:pretreated sewage sludge ratio of 2:1 in the mixture, the peak hydrogen production value was 5.0 L H2/L/d. As the production of hydrogen increased, propionate levels fell but butyrate concentrations rose gradually.

Membrane thickening aerobic digestion processes.

PubMed

Woo, Bryen

2014-01-01

Sludge management accounts for approximately 60% of the total wastewater treatment plant expenditure and laws for sludge disposal are becoming increasingly stringent, therefore much consideration is required when designing a solids handling process. A membrane thickening aerobic digestion process integrates a controlled aerobic digestion process with pre-thickening waste activated sludge using membrane technology. This process typically features an anoxic tank, an aerated membrane thickener operating in loop with a first-stage digester followed by second-stage digestion. Membrane thickening aerobic digestion processes can handle sludge from any liquid treatment process and is best for facilities obligated to meet low total phosphorus and nitrogen discharge limits. Membrane thickening aerobic digestion processes offer many advantages including: producing a reusable quality permeate with minimal levels of total phosphorus and nitrogen that can be recycled to the head works of a plant, protecting the performance of a biological nutrient removal liquid treatment process without requiring chemical addition, providing reliable thickening up to 4% solids concentration without the use of polymers or attention to decanting, increasing sludge storage capacities in existing tanks, minimizing the footprint of new tanks, reducing disposal costs, and providing Class B stabilization.

Clay-sewage sludge co-pyrolysis. A TG-MS and Py-GC study on potential advantages afforded by the presence of clay in the pyrolysis of wastewater sewage sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ischia, Marco, E-mail: marco.ischia@ing.unitn.it; Maschio, Roberto Dal; Grigiante, Maurizio

2011-01-15

Wastewater sewage sludge was co-pyrolyzed with a well characterized clay sample, in order to evaluate possible advantages in the thermal disposal process of solid waste. Characterization of the co-pyrolysis process was carried out both by thermogravimetric-mass spectrometric (TG-MS) analysis, and by reactor tests, using a lab-scale batch reactor equipped with a gas chromatograph for analysis of the evolved gas phase (Py-GC). Due to the presence of clay, two main effects were observed in the instrumental characterization of the process. Firstly, the clay surface catalyzed the pyrolysis reaction of the sludge, and secondly, the release of water from the clay, atmore » temperatures of approx. 450-500 deg. C, enhanced gasification of part of carbon residue of the organic component of sludge following pyrolysis. Moreover, the solid residue remaining after pyrolysis process, composed of the inorganic component of sludge blended with clay, is characterized by good features for possible disposal by vitrification, yielding a vitreous matrix that immobilizes the hazardous heavy metals present in the sludge.« less

Spectroscopic study of the humification process during sewage sludge treatment

NASA Astrophysics Data System (ADS)

Pajączkowska, J.; Sułkowska, A.; Sułkowski, W. W.; Jędrzejczyk, M.

2003-06-01

The aim of this work was to study the free radical transition of organic materials during the sewage treatment process. Investigations of sludge from biologic-mechanical sewage treatment plant in Sosnowiec Zagórze were carried out. The course of the humification processes during sewage treatment was studied by electron paramagnetic resonance (EPR) technique. The concentration of free radicals at each process stage and the value g were determined. Sludge samples and extracted fractions of humic acids were examined. Humic acids were extracted from sludge by means of conventional methods elaborated by Stevenson. For study of humic acids structures, besides EPR, the UV-Vis and IR spectroscopy were used.

Selective sequential precipitation of dissolved metals in mine drainage from coal mine

NASA Astrophysics Data System (ADS)

Yim, Giljae; Bok, Songmin; Ji, Sangwoo; Oh, Chamteut; Cheong, Youngwook; Han, Youngsoo; Ahn, Joosung

2017-04-01

In abandoned mines in Korea, a large amount of mine drainage continues to flow out and spread pollution. In purification of the mine drainage a massive amount of sludge is generated as waste. Since this metal sludge contains high Fe, Al and Mn oxides, developing the treatment method to recover homogeneous individual metal with high purity may beneficial to recycle waste metals as useful resources and reduce the amount of sludge production. In this regard, we established a dissolved metals selective precipitation process to treat Waryong Industry's mine drainage. The process that selectively precipitates metals dissolved in mine drainage is a continuous Fe-buffer-Al process, and each process consists of the neutralization tank, the coagulation tank, and the settling tank. Based on this process, this study verified the operational applicability of the Fe and Al selective precipitation. Our previous study revealed that high-purity Fe and Al precipitates could be recovered at a flow rate of 1.5 ton/day, while the lower purity was achieved when the rate was increased to about 3 ton/day due to the difficulty in reagent dosage control. In the current study was conducted to increase the capacity of the system to recover Fe and Al as high-purity precipitates at a flow rate of 10 ton/day with the ensured continuous operations by introducing an automatic reagent injection system. The previous study had a difficulty in controlling the pH and operating system continuously due to the manually controlled reagent injection system. To upgrade this and ensure the optimal pH in a stable way, a continuous reagent injection system was installed. The result of operation of the 10 ton/day system confirmed that the scaled-up process could maintain the stable recovery rates and purities of precipitates on site.

Rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment.

PubMed

Liu, Jibao; Yu, Dawei; Zhang, Jian; Yang, Min; Wang, Yawei; Wei, Yuansong; Tong, Juan

2016-07-01

The rheological behavior of sludge is of serious concern in anaerobic digestion. This study investigated the rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment (MW-H2O2). The results showed that MW-H2O2 pretreatment resulted in the improvement of sludge flowability and weakening of its viscoelastic properties. Further positive effects on the rheological properties of digested sludge during anaerobic digestion were observed. The flowability was improved with a low level of apparent viscosity. The decrease of the consistency index and increase of the flow behavior index indicated that the strength of the inner structures and non-Newtonian flow characteristics of digested sludge weakened. Both the storage modulus (G') and loss modulus (G″) decreased, indicating that the viscoelastic behavior became weak. These effects were possibly attributed to the changes of the digested sludge micro-structures, such as extracellular polymeric substances (EPS). This study concluded that anaerobic digestion for treating sewage sludge combined with pretreatment is a more favorable option than single anaerobic digestion from the perspective of rheology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultrasound assisted biogas production from co-digestion of wastewater sludges and agricultural wastes: Comparison with microwave pre-treatment.

PubMed

Aylin Alagöz, B; Yenigün, Orhan; Erdinçler, Ayşen

2018-01-01

This study investigates the effect of ultrasonication and microwave sludge disintegration/pre-treatment techniques on the anaerobic co-digestion efficiency of wastewater sludges with olive and grape pomaces. The effects of both co-digestion and sludge pre-treatment techniques were evaluated in terms of the organic removal efficiency and the biogas production. The "co-digestion" of wastewater sludge with both types of pomaces was revealed to be a much more efficient way for the biogas production compared to the single (mono) sludge digestion. The ultrasonication and microwave pre-treatments applied to the sludge samples caused to a further increase in biogas and methane yields. Based on applied specific energies, ultrasonication pre-treatment was found much more effective than microwave irradiation. The specific energy applied in microwave pre-treatment (87,000kj/kgTS) was almost 9 times higher than that of used in ultrasonication (10,000kj/kgTS), resulting only 10-15% increases in biogas/methane yield. Co-digestion of winery and olive industry residues with pre-treated wastewater sludges appears to be a suitable technique for waste management and energy production. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of deodorants on treatment of boat holding-tank waste

NASA Astrophysics Data System (ADS)

Walker, William R.; Haley, Carol J.; Bridgeman, Phyllis; Goldstein, Stephen H.

1991-05-01

A literature search and survey of Virginia, USA, campgrounds with RV pump-out stations were used to determine whether boat holding-tank deodorant chemicals would have deleterious effects on marina septic systems or package treatment plants. Laboratory studies reported in the literature indicate that these chemical additives could affect septic system function in three ways: (1) active ingredients in the additives can impair sewage degradation in septic tanks, causing sludge buildup and overflow of solids into the drainfield, (2) additive chemicals might enter the drainfield and, in high enough concentrations, reduce the drainfield's ability to degrade waste, or (3) toxic additive chemicals might migrate from the drainfield to ground or surface water. Laboratory studies also show that some ingredients added to holding tanks interfere with functioning of activated sludge treatment process. Experience in the field and in other laboratory studies suggests that factors such as dilution of treated waste with untreated waste and the characteristics of the sewage to be treated can reduce the possibility of damage to septic and activated sludge systems. The campground owners surveyed indicated that they have few problems with their septic systems in spite of the presence of chemical additives in the RV waste. However, most of them practice good septic system maintenance and have devised other means of ensuring that their systems function efficiently. In addition, the survey indicates that most Virginia campgrounds get only seasonal use (as would marinas in Virginia), allowing their systems to recover between peak seasons.

Polyhydroxyalkanoate (PHA) accumulation potential and PHA-accumulating microbial communities in various activated sludge processes of municipal wastewater treatment plants.

PubMed

Sakai, K; Miyake, S; Iwama, K; Inoue, D; Soda, S; Ike, M

2015-01-01

To clarify the polyhydroxyalkanoate (PHA) accumulation potential and the PHA-accumulating microbial community structure in activated sludge in municipal wastewater treatment plants (WWTPs) and to identify their influential factors. Nine activated sludge samples were collected from municipal WWTPs employing various biological treatment processes. In acetate-fed 24-h batch experiments under aerobic and nitrogen- and phosphorus-limited conditions, polyhydroxybutyrate (PHB) content of activated sludge increased from 0-1·3 wt% to 7·9-24 wt%, with PHB yields of 0·22-0·50 C-mol 3-hydroxybutyrate (C-mol acetate)(-1). Microbial community analyses found that activated sludge samples that accumulated >20 wt% of PHB after 24-h PHA accumulation experiments had >5·0 × 10(8) copies g(-1)-mixed liquor-suspended solid of phaC genes. Results indicated that (i) activated sludge in municipal WWTPs can accumulate up to approx. 20 wt% of PHA without enrichment processes, (ii) PHA accumulation potential of activated sludge varied depending on the operational conditions (treatment processes) of WWTPs, and (iii) phaC gene number can provide a simple indication of PHA accumulation potential. This is the first study to compare the PHA accumulation potential and PHA-accumulating microbial communities in activated sludge of various treatment processes. Our findings may be useful for enhancing the resource recovery potential of wastewater treatment systems. © 2014 The Society for Applied Microbiology.

Excess sludge disruption and pollutant removal from tannery effluent by upgraded activated sludge system.

PubMed

Sodhi, Vijay; Bansal, Ajay; Jha, Mithilesh Kumar

2018-04-30

This study proposed a maintenance metabolism based upgraded activated sludge as MANODOX system that restricts excess biosludge generation from high strength real tannery effluent. The MANODOX experimental demonstration has been done using a sequenced operational arrangement of a MBBR, anaerobic digester, and oxidation ditch connected to CAS reactor, discussed in detail manner. Experimental trends revealed a prominently lower sludge yield upto 0.271 gVSS/gCOD (72% overall sludge reduction) that corresponds to parallel run CAS (0.92 gVSS/gCOD). MANODOX implementation confirmed high quality treated effluent with prominent COD and suspended solids reduction upto 97.1% and 96% respectively. The biodegradability observation was further supported by anaerobic and aerobic batch digestion analysis. The variation of soluble component turbidity analysis reflects the enriched non-flocculating predatory microbial population appears to may have been responsible for sludge reduction. MANODOX system provided a sustainable practical alternative for under capacity activated sludge based treatment facilities for a variety of wastewater types. Copyright © 2018 Elsevier Ltd. All rights reserved.

Community composition of known and uncultured archaeal lineages in anaerobic or anoxic wastewater treatment sludge.

PubMed

Kuroda, Kyohei; Hatamoto, Masashi; Nakahara, Nozomi; Abe, Kenichi; Takahashi, Masanobu; Araki, Nobuo; Yamaguchi, Takashi

2015-04-01

Microbial systems are widely used to treat different types of wastewater from domestic, agricultural, and industrial sources. Community composition is an important factor in determining the successful performance of microbial treatment systems; however, a variety of uncultured and unknown lineages exist in sludge that requires identification and characterization. The present study examined the archaeal community composition in methanogenic, denitrifying, and nitrogen-/phosphate-removing wastewater treatment sludge by Archaea-specific 16S rRNA gene sequencing analysis using Illumina sequencing technology. Phylotypes belonging to Euryarchaeota, including methanogens, were most abundant in all samples except for nitrogen-/phosphate-removing wastewater treatment sludge. High levels of Deep Sea Hydrothermal Vent Group 6 (DHVEG-6), WSA2, Terrestrial Miscellaneous Euryarchaeotal Group, and Miscellaneous Crenarchaeotic Group were also detected. Interestingly, DHVEG-6 was dominant in nitrogen-/phosphate-removing wastewater treatment sludge, indicating that unclear lineages of Archaea still exist in the anaerobic wastewater treatment sludges. These results reveal a previously unknown diversity of Archaea in sludge that can potentially be exploited for the development of more efficient wastewater treatment strategies.

Ecological and Economic Aspects of the Application of Sewage Sludge in Energetic Plant Plantations - A Swot Analysis

NASA Astrophysics Data System (ADS)

Wójcik, Marta; Stachowicz, Feliks; Masłoń, Adam

2017-12-01

Sewage sludge management in Poland is a relatively new field of waste management called "in statu nascendi", the standards of which have not been recognized yet. It also requires the implementation of new solutions in the field of sewage sludge. So far, the most popular method of sewage sludge utilization has been landfill disposal. In line with the restriction placed on landfill waste with a calorific value above 6 MJ/kg introduced on 1 January 2016, agricultural use and thermal methods are particularly applied. Municipal sewage sludge may be successfully used in the cultivation of energetic plant plantations. The aforementioned waste could be treated as an alternative to traditional mineral fertilizers, which in turn might successfully provide valuable nutrients for plants. This paper illustrates the SWOT analysis (Strengths, Weaknesses, Opportunities, and Threats) associated with the use of sewage sludge from Świlcza-Kamyszyn WTTP (Podkarpackie Province, Poland) for agricultural purposes. This analysis could be useful in evaluating the utility of sewage sludge in perennial plant plantations in order to determine the appropriate waste management strategies.

Solubilization of municipal sewage waste activated sludge by novel lytic bacterial strains.

PubMed

Lakshmi, M Veera; Merrylin, J; Kavitha, S; Kumar, S Adish; Banu, J Rajesh; Yeom, Ick-Tae

2014-02-01

Extracellular polymeric substances (EPS) are an extracellular matrix found in sludge which plays a crucial role in flocculation by interacting with the organic solids. Therefore, to enhance pretreatment of sludge, EPS have to be removed. In this study, EPS were removed with a chemical extractant, NaOH, to enhance the bacterial pretreatment. A lysozyme secreting bacterial consortium was isolated from the waste activated sludge (WAS). The result of density gradient gel electrophoresis (DGGE) analysis revealed that the isolated consortium consists of two strains. The two novel strains isolated were named as Jerish03 (NCBI accession number KC597266) and Jerish 04 (NCBI accession number KC597267) and they belong to the genus Bacillus. Pretreatment with these novel strains enhances the efficiency of the aerobic digestion of sludge. Sludge treated with the lysozyme secreting bacterial consortium produced 29 % and 28.5 % increase in suspended solids (SS) reduction and chemical oxygen demand (COD) removal compared to the raw activated sludge (without pretreatment) during aerobic digestion. It is specified that these two novel strains had a high potential to enhance WAS degradation efficiency in aerobic digestion.

Investigation on extracellular polymeric substances, sludge flocs morphology, bound water release and dewatering performance of sewage sludge under pretreatment with modified phosphogypsum.

PubMed

Dai, Quxiu; Ma, Liping; Ren, Nanqi; Ning, Ping; Guo, Zhiying; Xie, Longgui; Gao, Haijun

2018-06-06

Modified phosphogypsum (MPG) was developed to improve dewaterability of sewage sludge, and dewatering performance, properties of treated sludge, composition and morphology distribution of EPS, dynamic analysis and multiple regression model on bound water release were investigated. The results showed that addition of MPG caused extracellular polymeric substances (EPS) disintegration through charge neutralization. Destruction of EPS promoted the formation of larger sludge flocs and the release of bound water into supernatant. Simultaneously, content of organics with molecular weight between 1000 and 7000 Da in soluble EPS (SB-EPS) increased with increasing of EPS dissolved into the liquid phase. Besides, about 8.8 kg•kg -1 DS of bound water was released after pretreatment with 40%DS MPG dosage. Additionally, a multiple linear regression model for bound water release was established, showing that lower loosely bond EPS (LB-EPS) content and specific resistance of filtration (SRF) may improve dehydration performance, and larger sludge flocs may be beneficial for sludge dewatering. Copyright © 2018 Elsevier Ltd. All rights reserved.

DEMONSTRATION BULLETIN: THE BASIC EXTRACTIVE SLUDGE TREATMENT (B.E.S.T.) RESOURCES CONSERVATION COMPANY (RCC)

EPA Science Inventory

The Basic Extractive Sludge Treatment (B.E.S.T.®) process is a solvent extraction system that separates organic contaminants from sludges, soils, and sediments. The primary distinguishing feature of the process is the extraction agent, triethylamine. The key to the success of tri...

Enhancement of waste activated sludge aerobic digestion by electrochemical pre-treatment.

PubMed

Song, Li-Jie; Zhu, Nan-Wen; Yuan, Hai-Ping; Hong, Ying; Ding, Jin

2010-08-01

Electrochemical technology with a pair of RuO(2)/Ti mesh plate electrode is first applied to pre-treat Waste Activated Sludge (WAS) prior to aerobic digestion in this study. The effects of various operating conditions were investigated including electrolysis time, electric power, current density, initial pH of sludge and sludge concentration. The study showed that the sludge reduction increased with the electrolysis time, electric power or current density, while decreased with the sludge concentration. Additionally, higher or lower pH than 7.0 was propitious to remove organic matters. The electrochemical pre-treatment removed volatile solids (VS) and volatile suspended solids (VSS) by 2.75% and 7.87%, respectively, with a WAS concentration of 12.9 g/L, electrolysis time of 30 min, electric power of 5 W and initial sludge pH of 10. In the subsequent aerobic digestion, the sludge reductions for VS and VSS after solids retention time (SRT) of 17.5 days were 34.25% and 39.59%, respectively. However, a SRT of 23.5 days was necessary to achieve equivalent reductions without electrochemical pre-treatment. Sludge analysis by Scanning Electron Microscope (SEM) images and infrared (IR) spectra indicated that electrochemical pre-treatment can rupture sludge cells, remove and solubilize intracellular substances, especially protein and polysaccharide, and consequently enhance the aerobic digestion. (c) 2010 Elsevier Ltd. All rights reserved.

Tracing pharmaceuticals in a municipal plant for integrated wastewater and organic solid waste treatment.

PubMed

Jelic, Aleksandra; Fatone, Francesco; Di Fabio, Silvia; Petrovic, Mira; Cecchi, Franco; Barcelo, Damia

2012-09-01

The occurrence and removal of 42 pharmaceuticals, belonging to different therapeutic groups (analgesics and anti-inflammatory drugs, anti-ulcer agent, psychiatric drugs, antiepileptic drug, antibiotics, ß-blockers, diuretics, lipid regulator and cholesterol lowering statin drugs and anti-histamines), were studied in the wastewater and sewage sludge trains of a full scale integrated treatment plant. The plant employs a biological nutrient removal (BNR) process for the treatment of municipal wastewater, and a single-stage mesophilic anaerobic co-digestion for the treatment of wasted activated sludge mixed with the organic fraction of municipal solid waste (OFMSW), followed by a short-cut nitrification-denitrification of the anaerobic supernatant in a sequential batch reactor. Influent and effluent wastewater, as well as thickened, digested and treated sludge were sampled and analyzed for the selected pharmaceuticals in order to study their presence and fate during the treatment. Twenty three compounds were detected in influent and effluent wastewater and eleven in sludge. Infiltration of groundwater in the sewer system led to a dilution of raw sewage, resulting in lower concentrations in wastewater (up to 0.7 μg/L in influent) and sludge (70 ng/g d.w.). Due to the dilution, overall risk quotient for the mixture of pharmaceuticals detected in effluent wastewater was less than one, indicating no direct risk for the aquatic environment. A wide range of removal efficiencies during the treatment was observed, i.e. <20% to 90%. The influent concentrations of the target pharmaceuticals, as polar compounds, were undoubtedly mostly affected by BNR process in the wastewater train, and less by anaerobic-co-digestion. Mass balance calculations showed that less than 2% of the total mass load of the studied pharmaceuticals was removed by sorption. Experimentally estimated distribution coefficients (<500 L/kg) also indicated that the selected pharmaceuticals preferably remain in the aqueous phase, and that biodegradation/transformation is the primary removal mechanism for these compounds during wastewater treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

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

PubMed

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

2014-01-01

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

Aerobic sludge digestion under low dissolved oxygen concentrations.

PubMed

Arunachalam, RaviSankar; Shah, Hemant K; Ju, Lu-Kwang

2004-01-01

Low dissolved oxygen (DO) concentrations occur commonly in aerobic digesters treating thickened sludge, with benefits of smaller digester size, much reduced aeration cost, and higher digestion temperature (especially important for plants in colder areas). The effects of low DO concentrations on digestion kinetics were studied using the sludge from municipal wastewater treatment plants in Akron, Ohio, and Los Lunas, New Mexico. The experiments were conducted in both batch digestion and a mixed mode of continuous, fed-batch, and batch operations. The low DO condition was clearly advantageous in eliminating the need for pH control because of the simultaneous occurrence of nitrification and denitrification. However, when compared with fully aerobic (high DO) systems under constant pH control (rare in full-scale plants), low DO concentrations and a higher solids loading had a negative effect on the specific volatile solids (VS) digestion kinetics. Nonetheless, the overall (volumetric) digestion performance depends not only on the specific digestion kinetics, but also the solids concentration, pH, and digester temperature. All of the latter factors favor the low DO digestion of thickened sludge. The significant effect of temperature on low DO digestion was confirmed in the mixed-mode study with the Akron sludge. When compared with the well-known empirical correlation between VS reduction and the product (temperature x solids retention time), the experimental data followed the same trend, but were lower than the correlation predictions. The latter was attributed to the lower digestible VS in the Akron sludge, the slower digestion at low DO concentrations, or both. Through model simulation, the first-order decay constant (kd) was estimated as 0.004 h(-1) in the mixed-mode operations, much lower than those (0.011 to 0.029 h(-1)) obtained in batch digestion. The findings suggested that the interactions among sludges with different treatment ages may have a substantially negative effect on digestion kinetics. The use of multistage digesters, especially with small front-end reactors, may be advantageous in both "process" kinetics and "biological reaction" kinetics for sludge digestion.

Comparison of concentration methods for rapid detection of hookworm ova in wastewater matrices using quantitative PCR.

PubMed

Gyawali, P; Ahmed, W; Jagals, P; Sidhu, J P S; Toze, S

2015-12-01

Hookworm infection contributes around 700 million infections worldwide especially in developing nations due to increased use of wastewater for crop production. The effective recovery of hookworm ova from wastewater matrices is difficult due to their low concentrations and heterogeneous distribution. In this study, we compared the recovery rates of (i) four rapid hookworm ova concentration methods from municipal wastewater, and (ii) two concentration methods from sludge samples. Ancylostoma caninum ova were used as surrogate for human hookworm (Ancylostoma duodenale and Necator americanus). Known concentration of A. caninum hookworm ova were seeded into wastewater (treated and raw) and sludge samples collected from two wastewater treatment plants (WWTPs) in Brisbane and Perth, Australia. The A. caninum ova were concentrated from treated and raw wastewater samples using centrifugation (Method A), hollow fiber ultrafiltration (HFUF) (Method B), filtration (Method C) and flotation (Method D) methods. For sludge samples, flotation (Method E) and direct DNA extraction (Method F) methods were used. Among the four methods tested, filtration (Method C) method was able to recover higher concentrations of A. caninum ova consistently from treated wastewater (39-50%) and raw wastewater (7.1-12%) samples collected from both WWTPs. The remaining methods (Methods A, B and D) yielded variable recovery rate ranging from 0.2 to 40% for treated and raw wastewater samples. The recovery rates for sludge samples were poor (0.02-4.7), although, Method F (direct DNA extraction) provided 1-2 orders of magnitude higher recovery rate than Method E (flotation). Based on our results it can be concluded that the recovery rates of hookworm ova from wastewater matrices, especially sludge samples, can be poor and highly variable. Therefore, choice of concentration method is vital for the sensitive detection of hookworm ova in wastewater matrices. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Application of ATAD technology for digesting sewage sludge in small towns: Operation and costs.

PubMed

Martín, M A; Gutiérrez, M C; Dios, M; Siles, J A; Chica, A F

2018-06-01

In an economic context marked by increasing energy costs and stricter legislation regarding the landfill disposal of wastewater treatment plant (WWTP) sewage sludge, and where biomethanization is difficult to implement in small WWTPs, an efficient alternative is required to manage this polluting waste. This study shows that autothermal thermophilic aerobic digestion (ATAD) is a feasible technique for treating sewage sludge in small- and medium-sized towns. The experiments were carried out at pilot scale on a cyclical basis and in continuous mode for nine months. The main results showed an optimal hydraulic retention time of 7 days, which led to an organic matter removal of 34%. The sanitized sludge meets the microbial quality standards for agronomic application set out in the proposed European sewage sludge directive. An economic assessment for the operation of ATAD technology was carried out, showing a treatment cost of €6.5/ton for dewatered sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Two strategies for phosphorus removal from reject water of municipal wastewater treatment plant using alum sludge.

PubMed

Yang, Y; Zhao, Y Q; Babatunde, A O; Kearney, P

2009-01-01

In view of the well recognized need of reject water treatment in MWWTP (municipal wastewater treatment plant), this paper outlines two strategies for P removal from reject water using alum sludge, which is produced as by-product in drinking water treatment plant when aluminium sulphate is used for flocculating raw waters. One strategy is the use of the alum sludge in liquid form for co-conditioning and dewatering with the anaerobically digested activated sludge in MWWTP. The other strategy involves the use of the dewatered alum sludge cakes in a fixed bed for P immobilization from the reject water that refers to the mixture of the supernatant of the sludge thickening process and the supernatant of the anaerobically digested sludge. Experimental trials have demonstrated that the alum sludge can efficiently reduce P level in reject water. The co-conditioning strategy could reduce P from 597-675 mg P/L to 0.14-3.20 mg P/L in the supernatant of the sewage sludge while the organic polymer dosage for the conditioning of the mixed sludges would also be significantly reduced. The second strategy of reject water filtration with alum sludge bed has shown a good performance of P reduction. The alum sludge has P-adsorption capacity of 31 mg-P/g-sludge, which was tested under filtration velocity of 1.0 m/h. The two strategies highlight the beneficial utilization of alum sludge in wastewater treatment process in MWWTP, thus converting the alum sludge as a useful material, rather than a waste for landfill.

The Influence of Ultrasonic Cavitation on the Formation of Fe-Rich Intermetallics in A383 Alloy

NASA Astrophysics Data System (ADS)

Xuan, Yang; Liu, Tao; Nastac, Laurentiu; Brewer, Luke; Levin, Ilya; Arvikar, Vish

2018-06-01

The effect of ultrasonic treatment (UST) on the formation of Fe-rich intermetallics (including sludge) in the A383 alloy is investigated for different processing temperatures in the present study. Differential scanning calorimetry is used to analyze the precipitation temperature of the sludge phase. The results revealed that the sludge will precipitate at a temperature above that of the Al matrix and the precipitation temperature decreases with an increasing cooling rate. UST cavitation applied at different temperatures (600 °C to 750 °C) during the solidification process breaks the sludge into small island-like pieces. However, the aggregation trend of the sludge is not changed. Sludge with small size and uniform distribution is obtained when UST is applied at 600 °C, which is lower than the precipitation temperature of the sludge. At the highest temperature (850 °C), the application of UST has no effect on the formation of either sludge or α-Fe intermetallics. At 750 °C, UST promotes the formation of the sludge when applied at 750 °C.

Optimization of Ozonation Process for the Reduction of Excess Sludge Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design

PubMed Central

Subha, B.; Muthukumar, M.

2012-01-01

Sago industries effluent containing large amounts of organic content produced excess sludge which is a serious problem in wastewater treatment. In this study ozonation has been employed for the reduction of excess sludge production in activated sludge process. Central composite design is used to study the effect of ozone treatment for the reduction of excess sludge production in sago effluent and to optimise the variables such as pH, ozonation time, and retention time. ANOVA showed that the coefficient determination value (R 2) of VSS and COD reduction were 0.9689 and 0.8838, respectively. VSS reduction (81%) was achieved at acidic pH 6.9, 12 minutes ozonation, and retention time of 10 days. COD reduction (87%) was achieved at acidic pH 6.7, 8 minutes of ozonation time, and retention time of 6 days. Low ozonation time and high retention time influence maximum sludge reduction, whereas low ozonation time with low retention time was effective for COD reduction. PMID:22593666

Disintegration impact on sludge digestion process.

PubMed

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.

Reduction of sludge production from WWTP using thermal pretreatment and enhanced anaerobic methanisation.

PubMed

Graja, S; Chauzy, J; Fernandes, P; Patria, L; Cretenot, D

2005-01-01

The objective of the study presented here was to investigate the performance of an enhanced two-step anaerobic process for the treatment of WWTP sludge. This process was developed to answer the urgent need currently faced by WWTP operators to reduce the production of biosolids, for which disposal pathways are facing increasing difficulties. A pilot plant was operated on a full-scale WWTP (2,500 p.e.) over a period of 4 months. It consisted of a thermal pre-treatment of excess sludge at 175 degrees C and 40 min, followed by dewatering and methanisation of the centrate in a fixed-film reactor. The thermal lysis had a two-fold enhancing effect on sludge reduction efficiency: firstly, it allowed a decrease of the HRT in the methaniser to 2.9 days and secondly, it yielded biosolids with a high dewaterability. This contributed to further reductions in the final volume of sludge to be disposed of. The two-step process achieved a sludge reduction efficiency of 65% as TSS, thus giving an interesting treatment option for WWTP facing sludge disposal problems.

An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation.

PubMed

Cho, Hyun Uk; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

2013-11-15

Lab-scale High Efficiency Digestion (HED) systems containing a Mesophilic Anaerobic Reactor (MAR), Thermophilic Aerobic Reactor (TAR), liquid/solid separation unit, and thermal-alkaline treatment were developed to evaluate the efficiencies of sludge reduction and methane production. The HED process was divided into three phases to examine the influence of sludge pretreatment and pretreated sludge recirculation using TCOD and VSS reduction, COD solubilization, and methane production. The VSS removal with a solid/liquid separation unit, sludge recirculation, and thermal-alkaline treatment drastically increased up to 95% compared to the feed concentration. In addition, the results of COD solubilization and VSS/TSS showed that the solubilization of cells and organic matters by the thermal-alkaline treatment was highly increased, which was also consistent with the SEM images. In particular, the methane production rate increased 24-fold when the feed sludge and recirculated sludge were pretreated together. Collectively, the HED experiments performed with sludge recirculation and thermal-alkaline treatment demonstrated that the HED systems can be successfully employed for highly efficient sewage sludge reduction and methane gas production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rheological properties of disintegrated sewage sludge

NASA Astrophysics Data System (ADS)

Wolski, Paweł

2017-11-01

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

A review on sludge dewatering indices.

PubMed

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

2016-01-01

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

Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching.

PubMed

Zheng, Guanyu; Zhou, Lixiang

2011-10-15

Four inorganic mineral nutrients including NH4+, K+, Mg2+ and soluble inorganic phosphate (Pi) were investigated to reveal the potential limiting nutrients for tannery sludge bioleaching process driven by Acidithiobacillus species, and the feasibility of supplementing the limiting nutrients to accelerate tannery sludge bioleaching was studied in the present study. It was found that the concentration of Pi was lower than 3.5 mg/L throughout the whole bioleaching process, which is the most probable restricting nutrient for tannery sludge bioleaching. Further experiments revealed that the deficiency of Pi could seriously influence the growth of Acidithiobacillus thiooxidans and lower its oxidization capacity for S0, and the limiting concentration of Pi for the growth of A. thiooxidans was 6 mg/L. The low concentration of soluble Pi in sludge matrix was resulted from the extremely strong sorbing/binding capacity of tannery sludge for phosphate. The supplementation of more than 1.6 g/L KH2PO4 into tannery sludge bioleaching system could effectively stimulate the growth of Acidithiobacillus species, enhance Cr removal rate and further shorten tannery sludge bioleaching period from 10 days to 7 days. Therefore, inorganic phosphate supplementation is an effective and feasible method to accelerate tannery sludge bioleaching process, and the optimum dosage of KH2PO4 was 1.6 g/L for tannery sludge with 5.1% of total solids. Copyright © 2011 Elsevier Ltd. All rights reserved.

K Basins sludge removal temporary sludge storage tank system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mclean, M.A.

1997-06-12

Shipment of sludge from the K Basins to a disposal site is now targeted for August 2000. The current path forward for sludge disposal is shipment to Tank AW-105 in the Tank Waste Remediation System (TWRS). Significant issues of the feasibility of this path exist primarily due to criticality concerns and the presence of polychlorinated biphenyls (PCBS) in the sludge at levels that trigger regulation under the Toxic Substance Control Act. Introduction of PCBs into the TWRS processes could potentially involve significant design and operational impacts to both the Spent Nuclear Fuel and TWRS projects if technical and regulatory issuesmore » related to PCB treatment cannot be satisfactorily resolved. Concerns of meeting the TWRS acceptance criteria have evolved such that new storage tanks for the K Basins sludge may be the best option for storage prior to vitrification of the sludge. A reconunendation for the final disposition of the sludge is scheduled for June 30, 1997. To support this decision process, this project was developed. This project provides a preconceptual design package including preconceptual designs and cost estimates for the temporary sludge storage tanks. Development of cost estimates for the design and construction of sludge storage systems is required to help evaluate a recommendation for the final disposition of the K Basin sludge.« less

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

PubMed

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

2017-11-01

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

Antifoam Degradation Products in Off Gas and Condensate of Sludge Batch 9 Simulant Nitric-Formic Flowsheet Testing for the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, T.

Ten chemical processing cell (CPC) experiments were performed using simulant to evaluate Sludge Batch 9 for sludge-only and coupled processing using the nitric-formic flowsheet in the Defense Waste Processing Facility (DWPF). Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on eight of the ten. The other two were SRAT cycles only. Samples of the condensate, sludge, and off gas were taken to monitor the chemistry of the CPC experiments. The Savannah River National Laboratory (SRNL) has previously shown antifoam decomposes to form flammable organic products, (hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and propanal), that are presentmore » in the vapor phase and condensate of the CPC vessels. To minimize antifoam degradation product formation, a new antifoam addition strategy was implemented at SRNL and DWPF to add antifoam undiluted.« less

Oily Sludge Biodetoxification

DTIC Science & Technology

2011-05-01

Sustainability Development to Integration NAVSTA Naval Station NT not tested O&M operation and maintenance OSHA Occupational Safety and Health ...Safety and Health Administration The results presented here and data from previous pilot scale and prototype (Hawaii) demonstrations of oily sludge...designed to treat. While additional degradation may have occurred if the system was supplemented with micronutrients and operated in series, it is

[Evaluating the Significance of Odor Gas Released During the Directly Drying Process of Sludge: Based on the Multi-index Integrated Assessment Method].

PubMed

Ding, Wen-jie; Chen, Wen-he; Deng, Ming-jia; Luo, Hui; Li, Lin; Liu, Jun-xin

2016-02-15

Co-processing of sewage sludge using the cement kiln can realize sludge harmless treatment, quantity reduction, stabilization and reutilization. The moisture content should be reduced to below 30% to meet the requirement of combustion. Thermal drying is an effective way for sludge desiccation. Odors and volatile organic compounds are generated and released during the sludge drying process, which could lead to odor pollution. The main odor pollutants were selected by the multi-index integrated assessment method. The concentration, olfactory threshold, threshold limit value, smell security level and saturated vapor pressure were considered as indexes based on the related regulations in China and foreign countries. Taking the pollution potential as the evaluation target, and the risk index and odor emission intensity as evaluation indexes, the odor pollution potential rated evaluation model of the pollutants was built according to the Weber-Fechner law. The aim of the present study is to form the rating evaluation method of odor potential pollution capacity suitable for the directly drying process of sludge.

Micropollutant removal by attached and suspended growth in a hybrid biofilm-activated sludge process.

PubMed

Falås, P; Longrée, P; la Cour Jansen, J; Siegrist, H; Hollender, J; Joss, A

2013-09-01

Removal of organic micropollutants in a hybrid biofilm-activated sludge process was investigated through batch experiments, modeling, and full-scale measurements. Batch experiments with carriers and activated sludge from the same full-scale reactor were performed to assess the micropollutant removal rates of the carrier biofilm under oxic conditions and the sludge under oxic and anoxic conditions. Clear differences in the micropollutant removal kinetics of the attached and suspended growth were demonstrated, often with considerably higher removal rates for the biofilm compared to the sludge. For several micropollutants, the removal rates were also affected by the redox conditions, i.e. oxic and anoxic. Removal rates obtained from the batch experiments were used to model the micropollutant removal in the full-scale process. The results from the model and plant measurements showed that the removal efficiency of the process can be predicted with acceptable accuracy (± 25%) for most of the modeled micropollutants. Furthermore, the model estimations indicate that the attached growth in hybrid biofilm-activated sludge processes can contribute significantly to the removal of individual compounds, such as diclofenac. Copyright © 2013 Elsevier Ltd. All rights reserved.

K basins sludge removal sludge pretreatment system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, H.L.

1997-06-12

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

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

PubMed

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.

Flow of sewage sludge-borne phthalate esters (PAEs) from human release to human intake: implication for risk assessment of sludge applied to soil.

PubMed

Meng, Xiang-Zhou; Wang, Ying; Xiang, Nan; Chen, Ling; Liu, Zhigang; Wu, Bing; Dai, Xiaohu; Zhang, Yun-Hui; Xie, Zhiyong; Ebinghaus, Ralf

2014-04-01

The wide production and use of phthalate esters (PAEs) in both industry and commercial products lead to their ubiquitous existence in the environment. However, understanding flow and pathway of human exposure to PAEs from sources to receptors is necessary and challenging. In this study, we selected final sewage sludge, an inevitable byproduct of wastewater treatment plants (WWTP), as one type of important carrier/sources of PAEs to clarify the flow of PAEs between human and the environment, e.g. the release by human to sludge and in turn ingestion by human after these sludges were disposed as soil amendment. Twenty-five sludge samples were collected from 25 wastewater treatment plants (WWTPs) in Shanghai, East China. Of all 16 PAE congeners, di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DnBP) were predominant with mean concentrations of 97.4 and 22.4 μg/g dw, respectively, both locating at the high end of the global range. WWTP treating industrial waster generally contained higher PAEs compared to those treating domestic wastewater, but no positive relationship was found between PAE levels with the percentage of industrial wastewater. Principal component analysis (PCA) showed that similar PAE sources for all WWTPs in Shanghai with three exceptions, in which specific PAE products were made. The annual mass loadings via sludge of DEHP, DnBP, and Σ16PAEs were 31.4, 7.44, and 39.6 tons in Shanghai and 1042, 247, and 1314 tons in China, respectively, only accounting for 0.09% of the total consumption of PAEs in China. If this sludge is applied in soil, human will take 16.4 and 3.8 μg/kg bw for DEHP and DnBP every day, respectively, via dietary and soil ingestion, which were lower than the toxicological safety parameters. To the best of our knowledge, this is the first report to analyze the flow of sludge-borne PAEs from human release to human intake. Copyright © 2014 Elsevier B.V. All rights reserved.

Modelling carbon oxidation in pulp mill activated sludge systems: calibration of Activated Sludge Model No 3.

PubMed

Barañao, P A; Hall, E R

2004-01-01

Activated Sludge Model No 3 (ASM3) was chosen to model an activated sludge system treating effluents from a mechanical pulp and paper mill. The high COD concentration and the high content of readily biodegradable substrates of the wastewater make this model appropriate for this system. ASM3 was calibrated based on batch respirometric tests using fresh wastewater and sludge from the treatment plant, and on analytical measurements of COD, TSS and VSS. The model, developed for municipal wastewater, was found suitable for fitting a variety of respirometric batch tests, performed at different temperatures and food to microorganism ratios (F/M). Therefore, a set of calibrated parameters, as well as the wastewater COD fractions, was estimated for this industrial wastewater. The majority of the calibrated parameters were in the range of those found in the literature.

Final Environmental Impact Statement for Treating Transuranic (TRU)/Alpha Low-level Waste at the Oak Ridge National Laboratory Oak Ridge, Tennessee

DOE Office of Scientific and Technical Information (OSTI.GOV)

N /A

2000-06-30

The DOE proposes to construct, operate, and decontaminate/decommission a TRU Waste Treatment Facility in Oak Ridge, Tennessee. The four waste types that would be treated at the proposed facility would be remote-handled TRU mixed waste sludge, liquid low-level waste associated with the sludge, contact-handled TRU/alpha low-level waste solids, and remote-handled TRU/alpha low-level waste solids. The mixed waste sludge and some of the solid waste contain metals regulated under the Resource Conservation and Recovery Act and may be classified as mixed waste. This document analyzes the potential environmental impacts associated with five alternatives--No Action, the Low-Temperature Drying Alternative (Preferred Alternative), themore » Vitrification Alternative, the Cementation Alternative, and the Treatment and Waste Storage at Oak Ridge National Laboratory (ORNL) Alternative.« less

Bioelectricity Generation and Bioremediation of an Azo-Dye in a Microbial Fuel Cell Coupled Activated Sludge Process

PubMed Central

Khan, Mohammad Danish; Abdulateif, Huda; Ismail, Iqbal M.; Sabir, Suhail; Khan, Mohammad Zain

2015-01-01

Simultaneous bioelectricity generation and dye degradation was achieved in the present study by using a combined anaerobic-aerobic process. The anaerobic system was a typical single chambered microbial fuel cell (SMFC) which utilizes acid navy blue r (ANB) dye along with glucose as growth substrate to generate electricity. Four different concentrations of ANB (50, 100, 200 and 400 ppm) were tested in the SMFC and the degradation products were further treated in an activated sludge post treatment process. The dye decolorization followed pseudo first order kinetics while the negative values of the thermodynamic parameter ∆G (change in Gibbs free energy) shows that the reaction proceeds with a net decrease in the free energy of the system. The coulombic efficiency (CE) and power density (PD) attained peak values at 10.36% and 2,236 mW/m2 respectively for 200 ppm of ANB. A further increase in ANB concentrations results in lowering of cell potential (and PD) values owing to microbial inhibition at higher concentrations of toxic substrates. Cyclic voltammetry studies revealed a perfect redox reaction was taking place in the SMFC. The pH, temperature and conductivity remain 7.5–8.0, 27(±2°C and 10.6–18.2 mS/cm throughout the operation. The biodegradation pathway was studied by the gas chromatography coupled with mass spectroscopy technique, suggested the preferential cleavage of the azo bond as the initial step resulting in to aromatic amines. Thus, a combined anaerobic-aerobic process using SMFC coupled with activated sludge process can be a viable option for effective degradation of complex dye substrates along with energy (bioelectricity) recovery. PMID:26496083