Sample records for activated sludge plants

  1. Fate of linear alkylbenzene sulfonate (LAS) in activated sludge plants

    NARCIS (Netherlands)

    Temmink, B.G.; Klapwijk, A.


    Monitoring data were collected in a pilot-scale municipal activated sludge plant to assess the fate of the C12-homologue of linear alkyl benzene sulfonate (LAS-C12). The pilot-plant was operated at influent LAS-C12 concentrations between 2 and 12 mg/l and at sludge retention times of 10 and 27 days<

  2. Long term effects on petrochemical activated sludge on plants and soil. Plant growth and metal absorption

    Energy Technology Data Exchange (ETDEWEB)

    Tedesco, M.J.; Gianello, C. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Solos; Ribas, P.I.F.; Carvalho, E.B. [CORSAN-SITEL, Triunfo, RS (Brazil). Polo Petroquimico do Sul. Dept. de Operacao e Manutencao


    An experiment to study the effects of several application rates of excess activated sludge on plants, soil and leached water was started in 1985. Sludge was applied for six years and increased plant growth due to its nitrogen and phosphorous contribution, even though the decomposition rate in soil is low. Plant zinc, cadmium and nickel content increased with sludge application, while liming decreased the amounts of these metals taken up by plants. 9 refs., 8 tabs.

  3. Fate of linear alkylbenzene sulfonate (LAS) in activated sludge plants. (United States)

    Temmink, H; Klapwijk, Bram


    Monitoring data were collected in a pilot-scale municipal activated sludge plant to assess the fate of the C12-homologue of linear alkyl benzene sulfonate (LAS-C12). The pilot-plant was operated at influent LAS-C12 concentrations between 2 and 12 mg l(-1) and at sludge retention times of 10 and 27 days. Effluent and waste sludge concentrations varied between 5 and 10 microg l(-1) and between 37 and 69 microg g(-1) VSS, respectively. In the sludge samples only 2-8% was present as dissolved LAS-C12, whereas the remaining 92-98% was found to be adsorbed to the sludge. In spite of this high degree of sorption, more than 99% of the LAS-C12 load was removed by biodegradation, showing that not only the soluble fraction but also the adsorbed fraction of LAS-C12 is readily available for biodegradation. Sorption and biodegradation of LAS-C12 were also investigated separately. Sorption was an extremely fast and reversible process and could be described by a linear isotherm with a partition coefficient of 3.2 l g(-1) volatile suspended solids. From the results of biodegradation kinetic tests it was concluded that primary biodegradation of LAS-C12 cannot be described by a (growth) Monod model, but a secondary utilisation model should be used instead. The apparent affinity of the sludge to biodegrade LAS-C12 increased when the sludge was loaded with higher influent concentrations of LAS-C12.

  4. Optimization of the coke-oven activated sludge plants

    Energy Technology Data Exchange (ETDEWEB)

    Raizer Neto, Ernesto [Santa Catarina Univ., Florianopolis, SC (Brazil); Colin, Francois [Institut de Recherches Hydrologiques, 54 - Nancy (France); Prost, Christian [Laboratoire de Sciences de Genie Chimique, Nancy (France)


    In the coke-oven activated sludge plants one of the greatest problems of malfunction is due to inffluent variability. The composition and, or, concentration variations of the inffluent substrate, which can cause an unstable system, are function of the pollutant load. Nevertheless, the knowledge of the kinetic biodegradation of the coke-oven effluent represents the limiting factor to develop an effective biological treatment. This work describes a computational model of the biological treatment which was elaborated and validated from continuous pilot scale experiments and calibrated by comparing its predictions to the pilot experiment`s results. 12 refs., 9 figs., 3 tabs.

  5. Fate of xenobiotic compounds and plants activity in reed bed sludge treatment

    DEFF Research Database (Denmark)

    Chen, Xijuan; Pauli, Udo; Rehfus, Stefan

    different plants: bulrush (Typha), reed (Phragmites australis) and reed canary grass (Phalaris arundinacea) were planted into 12 containers with a size of 1m Х 1m X 1m which were builded with 20cm gravel and 50cm sludge to study the plants activity in sludge degradation process, 4 containers were left...

  6. Bacterial Diversity of Active Sludge in Wastewater Treatment Plant (United States)

    Jiang, Xin; Ma, Mingchao; Li, Jun; Lu, Anhuai; Zhong, Zuoshen

    A bacterial 16S rDNA gene clone library was constructed to analyze the bacterial diversity of active sludge in Gaobeidian Wastewater Treatment Plant, Beijing. The results indicated that the bacterial diversity of active sludge was very high, and the clones could be divided into 5 different groups. The dominant bacterial community was proteobacteria, which accounted for 76.7%. The dominant succession of bacterial community were as follows: the β-proteobacteria (39.8%), the uncultured bacteria (22.33%), the γ-proteobacteria (20.15%), the α-proteobacteria (6.79%), and the σ-proteobacteria (4.85%). Nitrosomonas-like and Nitrospira-like bacteria, such as Nitrosomonas sp. (1.94%) and uncultured Nitrospirae bacterium (11.65%) were also detected, which have played important roles in ammonia and nitrite oxidisers in the system. However, they were only a little amount because of their slow growth and less competitive advantage than heterotrophic bacteria. Denitrifying bacteria like Thauera sp. was at a high percentage, which implies a strong denitrification ability; Roseomonas sp. was also detected in the clone library, which could be related to the degradation of organophosphorus pesticide.

  7. Ecophysiology of novel core phylotypes in activated sludge wastewater treatment plants with nutrient removal

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Awata, Takanori; Nierychlo, Marta

    An in depth understanding of the ecology of activated sludge nutrient removal wastewater treatment systems requires detailed knowledge of the community composition and metabolic activities of individual members. Recent 16S rRNA gene amplicon surveys of activated sludge wastewater treatment plants...... with nutrient removal in Denmark indicate a core set of bacterial genera. These core genera are suggested to be responsible for the bulk of nutrient transformations underpinning the functions of these plants. While we know the basic in situ activities of some of these genera, there is little to no information...

  8. Characterization of the in situ ecophysiology of novel phylotypes in nutrient removal activated sludge treatment plants

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Awata, Takanori; Nierychlo, Marta


    An in depth understanding of the ecology of activated sludge nutrient removal wastewater treatment systems requires detailed knowledge of the community composition and metabolic activities of individual members. Recent 16S rRNA gene amplicon surveys of activated sludge wastewater treatment plants...... with nutrient removal indicate the presence of a core set of bacterial genera. These organisms are likely responsible for the bulk of nutrient transformations underpinning the functions of these plants. While the basic activities of some of these genera in situ are known, there is little to no information...

  9. Sludge reduction by predatory activity of aquatic oligochaetes in wastewater treatment plants: Science or fiction? A review

    NARCIS (Netherlands)

    Ratsak, C.H.; Verkuijlen, J.


    Biological aerobic wastewater treatment plants (WWTPs) produce a lot of excess sludge. The costs for handling this residual product are increasing, so the search for alternative techniques to reduce the amount of sludge has to be continued. Activated sludge consists of inorganic and organic substanc

  10. Production of biodegradable plastics from activated sludge generated from a food processing industrial wastewater treatment plant. (United States)

    Suresh Kumar, M; Mudliar, S N; Reddy, K M K; Chakrabarti, T


    Most of the excess sludge from a wastewater treatment plant (60%) is disposed by landfill. As a resource utilization of excess sludge, the production of biodegradable plastics using the sludge has been proposed. Storage polymers in bacterial cells can be extracted and used as biodegradable plastics. However, widespread applications have been limited by high production cost. In the present study, activated sludge bacteria in a conventional wastewater treatment system were induced, by controlling the carbon: nitrogen ratio to accumulate storage polymers. Polymer yield increased to a maximum 33% of biomass (w/w) when the C/N ratio was increased from 24 to 144, where as specific growth yield decreased with increasing C/N ratio. The conditions which are required for the maximum polymer accumulation were optimized and are discussed.

  11. Changes at an activated sludge sewage treatment plant alter the numbers of airborne aerobic microorganisms. (United States)

    Fernando, Nadeesha L; Fedorak, Phillip M


    In 1976, the activated sludge sewage treatment plant in Edmonton, Canada, was surveyed to determine the numbers of culturable airborne microorganisms. Many changes have been made at the plant to reduce odors and improve treatment efficiency, so in 2004 another survey was done to determine if these changes had reduced the bioaerosols. Covering the grit tanks and primary settling tanks greatly reduced the numbers of airborne microbes. Changing the design and operation of indoor automated sampling taps and sinks also reduced bioaerosols. The secondary was expanded and converted from a conventional activated sludge process using coarse bubble aeration to a biological nutrient removal system using fine bubble aeration. Although the surface area of the secondary more than doubled, the average number of airborne microorganisms in this part of the plant in 2004 was about 1% of that in 1976.

  12. The occurrence of intestinal parasites in swine slurry and their removal in activated sludge plants. (United States)

    Reinoso, Roberto; Becares, Eloy


    Thirteen intensive pig farms and two activated sludge treatment plants for pig slurry in north-western Spain were studied from April 2005 to June 2006 in order to evaluate the presence of enteric pathogens (Cryptosporidium, Giardia and helminths) and the efficiency with which they were removed. These parasites were present on 53%, 7% and 38% of the farms studied, respectively, with concentrations of 10(4)-10(5) oocysts per litre (/L) for Cryptosporidium, 10(3)cysts/L for Giardia and 10(2)-10(3) eggs/L for helminths. The overall removal of parasites in the pig slurry treatment plants ranged from 86.7% to over 99.99%. The results revealed a constant reduction at each stage of the treatment system, with activated sludge processes being the most effective treatment in reducing pathogens in pig slurry, 78-81% for Cryptosporidium oocysts and over 99.9% for helminth eggs. A heat drying procedure for sludge removed 4.3 log units of Cryptosporidium oocysts, demonstrating the excellent effectiveness of this treatment for reducing pathogens in sludge intended to be applied to land.

  13. Activated sludge inhibition capacity index

    Directory of Open Access Journals (Sweden)

    V. Surerus


    Full Text Available Toxic compounds in sewage or industrial wastewater may inhibit the biological activity of activated sludge impairing the treatment process. This paper evaluates the Inhibition Capacity Index (ICI for the assessment of activated sludge in the presence of toxicants. In this study, activated sludge was obtained from industrial treatment plants and was also synthetically produced. Continuous respirometric measurements were carried out in a reactor, and the oxygen uptake rate profile obtained was used to evaluate the impact of inhibiting toxicants, such as dissolved copper, phenol, sodium alkylbenzene sulfonate and amoxicillin, on activated sludge. The results indicate that ICI is an efficient tool to quantify the intoxication capacity. The activated sludge from the pharmaceutical industry showed higher resistance than the sludge from other sources, since toxicants are widely discharged in the biological treatment system. The ICI range was from 58 to 81% when compared to the synthetic effluent with no toxic substances.

  14. Benchmarking procedure for full-scale activated sludge plants

    NARCIS (Netherlands)

    Abusam, A.; Keesman, K.J.; Spanjers, H.; Straten, van G.


    To enhance development and acceptance of new control strategies, a standard simulation benchmarking methodology to evaluate the performance of wastewater treatment plants has recently been proposed. The proposed methodology is, however, for a typical plant and that works under typical loading and en

  15. Characteristics of microfauna and their relationships with the performance of an activated sludge plant in China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Kexin; XU Muqi; LIU Biao; CAO Hong


    The occurrence and abundance of the microfauna groups were compared with the physico-chemical and operational parameters of the Baoding Lugang Sewage Treatment Plant in China. Attached and crawling ciliates were the dominant groups of ciliates. Crawling ciliates and testate amoebae showed a strong association with effluent BOD5 (biochemical oxygen demand). Therefore, these two groups are likely to be useful bioindicators since their number decreased as the process produced poor quality effluent. Testate amoebae also had significant negative correlations with effluent TN (total nitrogen), NH4+-N, SS (suspended solids) and SVI (sludge volumetric index), which means that this group of ciliates may be indicators of good performance of the activated sludge system. Carnivorous ciliates and flagellates had significant positive correlations with SVI, suggesting that these two groups may be indicators of bad settlement conditions of sludge. As identification of the microfauna species is difficult and time-consuming, we recommend using microfauna functional groups to evaluate the performance of the activated sludge system.

  16. Use of Lecane rotifers for limiting Thiothrix filamentous bacteria in bulking activated sludge in a dairy wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    Kowalska Ewa


    Full Text Available Excessive growth of filamentous bacteria is a serious problem in many dairy wastewater treatment plants (WWTPs. The objective of the study was to determine whether Lecane inermis rotifers were able to reduce the density of Thiothrix bacteria in activated sludge originating from a dairy WWTP, as well as to identify the impact of rotifers on other organisms in sludge. On a laboratory scale, three experiments were conducted in which activated sludge with a predominance of Thiothrix was inoculated with rotifers at an initial concentration of app. 600 individuals/mL. The results showed that the rotifers, by feeding on the bacterium filaments, are able to reduce significantly the quantity of Thiothrix. A decline in Thiothrix abundance coincided with an improvement of the sedimentation properties of activated sludge. In addition, it was proven that Lecane inermis did not negatively affect the number of Protozoa and Metazoa in activated sludge.

  17. Ubiquity of activated sludge ferricyanide-mediated BOD methods: a comparison of sludge seeds across wastewater treatment plants. (United States)

    Jordan, Mark A; Welsh, David T; Teasdale, Peter R


    Many studies have described alternatives to the BOD5 standard method, with substantial decreases in incubation time observed. However, most of these have not maintained the features that make the BOD5 assay so relevant - a high level of substrate bio-oxidation and use of wastewater treatment plant (WWTP) sludge as the biocatalyst. Two recently described ferricyanide-mediated (FM)-BOD assays, one for trade wastes and one for WWTP influents and treated effluents, satisfy these criteria and were investigated further here for their suitability for use with diverse biocatalysts. Both FM-BOD assays responded proportionately to increasing substrate concentration with sludges from 11 different WWTPs and temporally (months to years) using sludges from a single WWTP, confirming the broad applicability of both assays. Sludges from four WWTPs were selected as biocatalysts for each FM-BOD assay to compare FM-BOD equivalent values with BOD5 (three different sludge seeds) measurements for 12 real wastewater samples (six per assay). Strong and significant relationships were established for both FM-BOD assays. This study has demonstrated that sludge sourced from many WWTPs may be used as the biocatalyst in either FM-BOD assay, as it is in the BOD5 assay. The industry potential of these findings is substantial given the widespread use of the BOD5 assay, the dramatically decreased incubation period (3-6h) and the superior analytical range of both assays compared to the standard BOD5 assay.

  18. Monitoring and troubleshooting of non-filamentous settling and dewatering problems in an industrial activated sludge treatment plant

    DEFF Research Database (Denmark)

    Kjellerup, B. V.; Keiding, Kristian; Nielsen, Per Halkjær


    A large industrial activated sludge wastewater treatment plant had temporary problems with settling and dewatering of the sludge. Microscopical investigations revealed that the poor settling properties were not due to presence of filamentous bacteria, but poor floc properties. In order...... at this industrial plant. The described strategy can be useful in general to find and solve many solid/liquid separation problems in activated sludge wastewater treatment plants....... had started after summer closedown. Possible reasons for the changes in floc properties in the process tanks were found by a) analysing change in wastewater composition by evaluating the different production lines in the industrial plant, b) evaluating the operation of the plant, and c) performing...


    Directory of Open Access Journals (Sweden)

    Dariusz Zdebik


    Full Text Available This paper presents a method for calibration of activated sludge model with the use of computer program BioWin. Computer scheme has been developed on the basis of waste water treatment plant operating in the sequential – flow technology. For calibration of the activated sludge model data of influent and treated effluent from the existing object were used. As a result of conducted analysis was a change in biokinetic model and kinetic parameters parameters of wastewater treatment facilities. The presented method of study of the selected parameters impact on the activated sludge biokinetic model (including autotrophs maximum growth rate, the share of organic slurry in suspension general operational, efficiency secondary settling tanks can be used for conducting simulation studies of other treatment plants.

  20. Metaproteomics of activated sludge from a wastewater treatment plant - a pilot study. (United States)

    Püttker, Sebastian; Kohrs, Fabian; Benndorf, Dirk; Heyer, Robert; Rapp, Erdmann; Reichl, Udo


    In this study, the impact of protein fractionation techniques prior to LC/MS analysis was investigated on activated sludge samples derived at winter and summer condition from a full-scale wastewater treatment plant (WWTP). For reduction of the sample complexity, different fractionation techniques including RP-LC (1D-approach), SDS-PAGE and RP-LC (2D-approach) as well as RP-LC, SDS-PAGE and liquid IEF (3D-approach) were carried out before subsequent ion trap MS analysis. The derived spectra were identified by MASCOT search using a combination of the public UniProtKB/Swiss-Prot protein database and metagenome data from a WWTP. The results showed a significant increase of identified spectra, enabled by applying IEF and SDS-PAGE to the proteomic workflow. Based on meta-proteins, a core metaproteome and a corresponding taxonomic profile of the wastewater activated sludge were described. Functional aspects were analyzed using the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway library by plotting KEGG Orthology identifiers (KO numbers) of protein hits into pathway maps of the central carbon (map01200) and nitrogen metabolism (map00910). Using the 3D-approach, most proteins involved in glycolysis and citrate cycle and nearly all proteins of the nitrogen removal were identified, qualifying this approach as most promising for future studies. All MS data have been deposited in the ProteomeXchange with identifier PXD001547 (

  1. Volatile fatty acids produced by co-fermentation of waste activated sludge and henna plant biomass. (United States)

    Huang, Jingang; Zhou, Rongbing; Chen, Jianjun; Han, Wei; Chen, Yi; Wen, Yue; Tang, Junhong


    Anaerobic co-fermentation of waste activated sludge (WAS) and henna plant biomass (HPB) for the enhanced production of volatile fatty acids (VFAs) was investigated. The results indicated that VFAs was the main constituents of the released organics; the accumulation of VFAs was much higher than that of soluble carbohydrates and proteins. HPB was an advantageous substrate compared to WAS for VFAs production; and the maximum VFAs concentration in an HPB mono-fermentation system was about 2.6-fold that in a WAS mono-fermentation system. In co-fermentation systems, VFAs accumulation was positively related to the proportion of HPB in the mixed substrate, and the accumulated VFAs concentrations doubled when HPB was increased from 25% to 75%. HPB not only adjust the C/N ratio; the associated and/or released lawsone might also have a positive electron-shuttling effect on VFAs production.

  2. Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    William Z. de Mello


    Full Text Available This study investigated the emission of N2O during the sequential aerated (60-min and non-aerated (30-min stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP. N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitrogen load and the per capita emission factor was almost 3 times higher than that suggested by the IPCC for inventories of N2O emission from WWTPs.

  3. Activated Sludge Rheology

    DEFF Research Database (Denmark)

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


    Rheological behaviour is an important fluid property that severely impacts its flow behaviour and many aspects related to this. In the case of activated sludge, the apparent viscosity has an influence on e.g. pumping, hydrodynamics, mass transfer rates, sludge-water separation (settling and filtr...

  4. Innovative strategies for the reduction of sludge production in activated sludge plant: BIOLYSIS O and BIOLYSIS E

    Energy Technology Data Exchange (ETDEWEB)

    Deleris, Stephane; Larose, A.; Geaugey, V.; Lebrunn, Thierry


    Management of the excess sludge production resulting from biological wastewater treatment is one of the most important economic and environmental issues for the next decade. New stringent regulations regarding sludge treatment and disposal imposed in several countries as well as social and environmental concerns, have resulted in an increasing interest in processes allowing the reduction of excess sludge production. Following a 5 years research program, Ondeo-Degremont has developed two processes, Biolysis O and Biolysis E, designed to reduce sludge production during biological wastewater treatment. Experiment performed with Biolysis technologies confirmed that high (up to 80%) reduction of excess sludge production can be reached while good treatment performances are maintained, in agreement with regulation standards. Economical data demonstrate the competitiveness of Biolysis processes. Such processes appear to be a valuable alternative to solve the problem of sludge treatment, to protect operators from the evolution of legislation of sludge treatment and from risks inherent to final sludge disposal.

  5. Molecular characterization of activated sludge from a seawater‐processing wastewater treatment plant (United States)

    Sánchez, Olga; Garrido, Laura; Forn, Irene; Massana, Ramon; Maldonado, Manuel Ignacio; Mas, Jordi


    Summary The prokaryotic community composition of activated sludge from a seawater‐processing wastewater treatment plant (Almeria, Spain) was investigated by using the rRNA approach, combining different molecular techniques such as denaturing gradient gel electrophoresis (DGGE), clone libraries and in situ hybridization (FISH and CARD‐FISH). Most of the sequences retrieved in the DGGE and the clone libraries were similar to uncultured members of different phyla. The most abundant sequence recovered from Bacteria in the clone library corresponded to a bacterium from the Deinococcus–Thermus cluster (almost 77% of the clones), and the library included members from other groups such as the Alpha, Gamma and Delta subclasses of Proteobacteria, the Bacteroidetes and Firmicutes. Concerning the archaeal clone library, we basically found sequences related to different orders of methanogenic Archaea, in correspondence with the recovered DGGE bands. Enumeration of DAPI (4′,6‐diamidino‐2‐phenylindole) stained cells from two different activated sludge samples after a mechanical flocculation disruption revealed a mean cell count of 1.6 × 109 ml−1. Around 94% of DAPI counts (mean value from both samples) hybridized with a Bacteria specific probe. Alphaproteobacteria were the dominant bacterial group (36% of DAPI counts), while Beta‐, Delta‐ and Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes contributed to lower proportions (between 0.5–5.7% of DAPI counts). Archaea accounted only for 6% of DAPI counts. In addition, specific primers for amplification of the amoA (ammonia monooxygenase) gene were used to detect the presence of Beta, Gamma and archaeal nitrifiers, yielding positive amplifications only for Betaproteobacteria. This, together with negative in situ hybridizations with probes for well‐known nitrifiying bacteria, suggests that nitrification is performed by still undetected microorganisms. In summary, the combination of the

  6. Toxic influence of silver and uranium salts on activated sludge of wastewater treatment plants and synthetic activated sludge associates modeled on its pure cultures. (United States)

    Tyupa, Dmitry V; Kalenov, Sergei V; Skladnev, Dmitry A; Khokhlachev, Nikolay S; Baurina, Marina M; Kuznetsov, Alexander Ye


    Toxic impact of silver and uranium salts on activated sludge of wastewater treatment facilities has been studied. Some dominating cultures (an active nitrogen fixer Agrobacterium tumifaciens (A.t) and micromyces such as Fusarium nivale, Fusarium oxysporum, and Penicillium glabrum) have been isolated and identified as a result of selection of the activated sludge microorganisms being steadiest under stressful conditions. For these cultures, the lethal doses of silver amounted 1, 600, 50, and 300 µg/l and the lethal doses of uranium were 120, 1,500, 1,000, and 1,000 mg/l, respectively. A.tumifaciens is shown to be more sensitive to heavy metals than micromyces. Synthetic granular activated sludge was formed on the basis of three cultures of the isolated micromyces steadiest against stress. Its granules were much more resistant to silver than the whole native activated sludge was. The concentration of silver causing 50 % inhibition of synthetic granular activated sludge growth reached 160-170 μg/l as far as for the native activated sludge it came only to 100-110 μg/l.

  7. Cost estimation and economical evaluation of three configurations of activated sludge process for a wastewater treatment plant (WWTP) using simulation (United States)

    Jafarinejad, Shahryar


    The activated sludge (AS) process is a type of suspended growth biological wastewater treatment that is used for treating both municipal sewage and a variety of industrial wastewaters. Economical modeling and cost estimation of activated sludge processes are crucial for designing, construction, and forecasting future economical requirements of wastewater treatment plants (WWTPs). In this study, three configurations containing conventional activated sludge (CAS), extended aeration activated sludge (EAAS), and sequencing batch reactor (SBR) processes for a wastewater treatment plant in Tehran city were proposed and the total project construction, operation labor, maintenance, material, chemical, energy and amortization costs of these WWTPs were calculated and compared. Besides, effect of mixed liquor suspended solid (MLSS) amounts on costs of WWTPs was investigated. Results demonstrated that increase of MLSS decreases the total project construction, material and amortization costs of WWTPs containing EAAS and CAS. In addition, increase of this value increases the total operation, maintenance and energy costs, but does not affect chemical cost of WWTPs containing EAAS and CAS.

  8. Enhancing filterability of activated sludge from landfill leachate treatment plant by applying electrical field ineffective on bacterial life. (United States)

    Akkaya, Gulizar Kurtoglu; Sekman, Elif; Top, Selin; Sagir, Ece; Bilgili, Mehmet Sinan; Guvenc, Senem Yazici


    The aim of this study is to investigate filterability enhancement of activated sludge supplied form a full-scale leachate treatment plant by applying DC electric field while keeping the biological operational conditions in desirable range. The activated sludge samples were received from the nitrification tank in the leachate treatment plant of Istanbul's Odayeri Sanitary Landfill Site. Experimental sets were conducted as laboratory-scale batch studies and were duplicated for 1A, 2A, 3A, 4A, and 5A of electrical currents and 2, 5, 10, 15, and 30 min of exposure times under continuous aeration. Physicochemical parameters such as temperature, pH, and oxidation reduction potential in the mixture right after each experimental set and biochemical parameters such as chemical oxygen demand, total phosphorus, and ammonia nitrogen in supernatant were analyzed to define the sets that remain in the range of ideal biological operational conditions. Later on, sludge filterability properties such as capillary suction time, specific resistance to filtration, zeta potential, and particle size were measured for remaining harmless sets. Additionally, cost analyses were conducted in respect to energy and electrode consumptions. Application of 2A DC electric field and 15-min exposure time was found to be the most favorable conditions to enhance filterability of the landfill leachate-activated sludge.

  9. Bioavailable and biodegradable dissolved organic nitrogen in activated sludge and trickling filter wastewater treatment plants (United States)

    A study was carried out to understand the fate of biodegradable dissolved organic nitrogen (BDON) and bioavailable dissolved organic nitrogen (ABDON) along the treatment trains of a wastewater treatment facility (WWTF) equipped with an activated sludge (AS) system and a WWTF equipped with a two-stag...

  10. The role and control of sludge age in biological nutrient removal activated sludge systems. (United States)

    Ekama, G A


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

  11. Fractionation of biogas plant sludge material improves metaproteomic characterization to investigate metabolic activity of microbial communities. (United States)

    Kohrs, Fabian; Wolter, Sophie; Benndorf, Dirk; Heyer, Robert; Hoffmann, Marcus; Rapp, Erdmann; Bremges, Andreas; Sczyrba, Alexander; Schlüter, Andreas; Reichl, Udo


    With the development of high resolving mass spectrometers, metaproteomics evolved as a powerful tool to elucidate metabolic activity of microbial communities derived from full-scale biogas plants. Due to the vast complexity of these microbiomes, application of suitable fractionation methods are indispensable, but often turn out to be time and cost intense, depending on the method used for protein separation. In this study, centrifugal fractionation has been applied for fractionation of two biogas sludge samples to analyze proteins extracted from (i) crude fibers, (ii) suspended microorganisms, and (iii) secreted proteins in the supernatant using a gel-based approach followed by LC-MS/MS identification. This fast and easy method turned out to be beneficial to both the quality of SDS-PAGE and the identification of peptides and proteins compared to untreated samples. Additionally, a high functional metabolic pathway coverage was achieved by combining protein hits found exclusively in distinct fractions. Sample preparation using centrifugal fractionation influenced significantly the number and the types of proteins identified in the microbial metaproteomes. Thereby, comparing results from different proteomic or genomic studies, the impact of sample preparation should be considered. All MS data have been deposited in the ProteomeXchange with identifier PXD001508 (

  12. Biodegradation of chlorpyrifos by Klebsiella sp. isolated from an activated sludge sample of waste water treatment plant in Damascus. (United States)

    Ghanem, I; Orfi, M; Shamma, M


    A chlorpyrifos (CPY)-degrading bacterial strain was isolated from an activated sludge sample collected from the Damascus Wastewater Treatment Plant, Syria. The isolation of Klebsiella sp. was facilitated by the addition of CPY at a rate of 3.84 g/L of sludge weekly (selection pressure). Identification of Klebsiella sp. was done using major staining and biochemical differentiation tests (Gram stain, cytochrome oxidase and some relevant saccharide fermentation tests using biochemical assays). Klebsiella sp. was maintained by culturing in a poor medium consisting of mineral salts and CPY as the sole carbon source. When 3 activated sludge samples were incubated in the presence of CPY (13.9 g/L sludge), 46% of added CPY were degraded within 4 d. By comparison, within 4 d the isolated Klebsiella sp. was found to break down 92% of CPY when co-incubated in a poor mineral medium in which CPY was the sole carbon source (13.9 g/L poor medium). Isolated Klebsiella sp. was able to tolerate up to 17.3 g of CPY in the poor medium.

  13. A pilot-scale study on PVA gel beads based integrated fixed film activated sludge (IFAS) plant for municipal wastewater treatment. (United States)

    Kumar Singh, Nitin; Singh, Jasdeep; Bhatia, Aakansha; Kazmi, A A


    In the present study, a pilot-scale reactor incorporating polyvinyl alcohol gel beads as biomass carrier and operating in biological activated sludge mode (a combination of moving bed biofilm reactor (MBBR) and activated sludge) was investigated for the treatment of actual municipal wastewater. The results, during a monitoring period of 4 months, showed effective removal of chemical oxygen demand (COD), biological oxygen demand (BOD) and NH3-N at optimum conditions with 91%, ∼92% and ∼90% removal efficiencies, respectively. Sludge volume index (SVI) values of activated sludge varied in the range of 25-72 mL/g, indicating appreciable settling characteristics. Furthermore, soluble COD and BOD in the effluent of the pilot plant were reduced to levels well below discharge limits of the Punjab Pollution Control Board, India. A culture dependent method was used to enrich and isolate abundant heterotrophic bacteria in activated sludge. In addition to this, 16S rRNA genes analysis was performed to identify diverse dominant bacterial species in suspended and attached biomass. Results revealed that Escherichia coli, Pseudomonas sp. and Nitrosomonas communis played a significant role in biomass carrier, while Acinetobactor sp. were dominant in activated sludge of the pilot plant. Identification of ciliated protozoa populations rendered six species of ciliates in the plant, among which Vorticella was the most dominant.


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    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.

  15. Enzyme Activities in Waste Water and Activated Sludge

    DEFF Research Database (Denmark)

    Nybroe, Ole; Jørgensen, Per Elberg; Henze, Mogens


    The purpose of the present study was to evaluate the potential of selected enzyme activity assays to determine microbial abundance and heterotrophic activity in waste water and activated sludge. In waste water, esterase and dehydrogenase activities were found to correlate with microbial abundance...... measured as colony forming units of heterotrophic bacteria. A panel of four enzyme activity assays, α-glucosidase, alanine-aminopeptidase, esterase and dehydrogenase were used to characterize activated sludge and anaerobic hydrolysis sludge from a pilot scale plant. The enzymatic activity profiles were...... distinctly different, suggesting that microbial populations were different, or had different physiological properties, in the two types of sludge. Enzyme activity profiles in activated sludge from four full-scale plants seemed to be highly influenced by the composition of the inlet. Addition of hydrolysed...

  16. Phylogeny, physiology and distribution of 'Candidatus Microthrix calida', a new Microthrix species isolated from industrial activated sludge wastewater treatment plants. (United States)

    Levantesi, Caterina; Rossetti, Simona; Thelen, Karin; Kragelund, Caroline; Krooneman, Janneke; Eikelboom, Dick; Nielsen, Per Halkjaer; Tandoi, Valter


    Twelve strains of filamentous bacteria morphologically identified as 'Microthrix parvicella' were isolated from industrial activated sludge wastewater treatment plants. 16S rRNA gene sequences analysis showed that these strains were all closely related to 'Candidatus Microthrix parvicella'. Six of them, however, had a 16S rRNA gene similarity of only 95.7% and 96.7% to 'Candidatus Microthrix parvicella' suggesting the presence of a new species. The name 'Candidatus Microthrix calida' is proposed for this new microorganism. The physiological properties of these six isolates supported the description of a new taxon. The 'Candidatus Microthrix calida' strains produced thin filaments (0.3-0.7 microm diameter), they did not grow on the media supporting the growth of 'Candidatus Microthrix parvicella' and could be cultivated at higher temperature (up to 36.5 degrees C). Preliminary data on substrate uptake were obtained by microautoradiography on pure culture. Two new fluorescence in situ hybridization (FISH) probes, Mpa-T1-1260 specific for 'Candidatus Microthrix calida' and Mpa-all-1410 targeting both Microthrix species, were designed. The presence of Microthrix spp. was investigated in 114 activated sludge plants. 'Microthrix parvicella' morphotype was detected in 23% of the analysed samples and FISH analysis revealed that 'Candidatus Microthrix calida' was present in 5% of them. The remaining 'M. parvicella' filaments were positive with probe Mpa-all-1410 but could not all be identified as 'Candidatus Microthrix parvicella' suggesting the presence of more hitherto undescribed biodiversity within this morphotype.

  17. Characterization and distribution of esterase activity in activated sludge

    NARCIS (Netherlands)

    Boczar, BA; Forney, LJ; Begley, WM; Larson, RJ; Federle, TW


    The location and activity of esterase enzymes in activated Sludge from three Municipal wastewater treatment plants were characterized using model Substrate, and denaturing and nondenaturing polyacrylamide gel electrophoresis (PAGE) Of particulate, freeze thaw (primarily periplasmic enzymes and those

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

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


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

  19. Production of volatile fatty acids by fermentation of waste activated sludge pre-treated in full-scale thermal hydrolysis plants. (United States)

    Morgan-Sagastume, F; Pratt, S; Karlsson, A; Cirne, D; Lant, P; Werker, A


    This work focuses on fermentation of pre-treated waste activated sludge (WAS) to generate volatile fatty acids (VFAs). Pre-treatment by high-pressure thermal hydrolysis (HPTH) was shown to aid WAS fermentation. Compared to fermentation of raw WAS, pre-treatment enabled a 2-5x increase in VFA yield (gVFA(COD)gTCOD(-1)) and 4-6x increase in VFA production rate (gVFA(COD) L(-1) d(-1)). Three sludges, pre-treated in full-scale HPTH plants, were fermented. One was from a plant processing a mix of primary sludge and WAS and the other two from plants processing solely WAS. The HPTH plants solubilised suspended matter, evidenced by a 20-30% decrease in suspended solids and an increase of soluble COD : total COD from 0.04 to 0.4. Fermentation of the three sludges yielded similar VFA concentrations (15-20gVFA(COD) L(-1)). The yields were largely independent of retention time (1 d-6 d) and temperature (42°C, 55°C). Also, the product spectrum depended mostly on the composition of the sludge rather than on operating conditions.

  20. Dynamics of microbiological parameters, enzymatic activities and worm biomass production during vermicomposting of effluent treatment plant sludge of bakery industry. (United States)

    Yadav, Anoop; Suthar, S; Garg, V K


    This paper reports the changes in microbial parameters and enzymatic activities during vermicomposting of effluent treatment plant sludge (ETPS) of bakery industry spiked with cow dung (CD) by Eisenia fetida. Six vermibins containing different ratios of ETPS and CD were maintained under controlled laboratory conditions for 15 weeks. Total bacterial and total fungal count increased upto 7th week and declined afterward in all the bins. Maximum bacterial and fungal count was 31.6 CFU × 10(6) g(-1) and 31 CFU × 10(4) g(-1) in 7th week. Maximum dehydrogenase activity was 1921 μg TPF g(-1) h(-1) in 9th week in 100 % CD containing vermibin, whereas maximum urease activity was 1208 μg NH4 (-)N g(-1) h(-1) in 3rd week in 100 % CD containing vermibin. The enzyme activity and microbial counts were lesser in ETPS containing vermibins than control (100 % CD). The growth and fecundity of the worms in different vermibins were also investigated. The results showed that initially biomass and fecundity of the worms increased but decreased at the later stages due to non-availability of the palatable feed. This showed that quality and palatability of food directly affect biological parameters of the system.

  1. Gravity Drainage of Activated Sludge on Reed Beds

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Dominiak, Dominik Marek; Keiding, Kristian;

    Activated sludge is a by-product from waste water treatment plants, and the water content in the sludge is high (> 90%). Among several methods to remove the water, sludge drying reed beds are often used to dewater the sludge by drainage. There is, however, no well-defined criterion for design...... has therefore been developed to measure relevant quality parameters: specific cake resistance, settling velocity and cake compressibility. It has been found that activated sludge form highly compressible cake even at the low compressive pressures obtained during drainage. Numerical simulation shows...... that the compressibility has a high influence on the drainage process especially during the start-up phases where the volumetric load on the sludge bed is critical. The load has to be low in order to ensure that the drainage properties of the bed are not destroyed. The data also shows that transport of activated sludge...

  2. Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

    DEFF Research Database (Denmark)

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


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

  3. Polyphasic bacterial community analysis of an aerobic activated sludge removing phenols and thiocyanate from coke plant effluent

    Energy Technology Data Exchange (ETDEWEB)

    Felfoldi, T.; Szekely, A.J.; Goral, R.; Barkacs, K.; Scheirich, G.; Andras, J.; Racz, A.; Marialigeti, K. [Eotvos Lorand University, Budapest (Hungary). Dept. of Microbiology


    Biological purification processes are effective tools in the treatment of hazardous wastes such as toxic compounds produced in coal coking. In this study, the microbial community of a lab-scale activated sludge system treating coking effluent was assessed by cultivation-based (strain isolation and identification, biodegradation tests) and culture-independent techniques (sequence-aided T-RFLP, taxon-specific PCR). The results of the applied polyphasic approach showed a simple microbial community dominated by easily culturable heterotrophic bacteria. Comamonas badia was identified as the key microbe of the system, since it was the predominant member of the bacterial community, and its phenol degradation capacity was also proved. Metabolism of phenol, even at elevated concentrations (up to 1500 mg/L), was also presented for many other dominant (Pseudomonas, Rhodanobacter, Oligella) and minor (Alcaligenes, Castellaniella, Microbacterium) groups, while some activated sludge bacteria (Sphingomonas, Rhodopseudomonas) did not tolerate it even in lower concentrations (250 mg/L). In some cases, closely related strains showed different tolerance and degradation properties. Members of the genus Thiobacillus were detected in the activated sludge, and were supposedly responsible for the intensive thiocyanate biodegradation observed in the system. Additionally, some identified bacteria (e.g. C. badia and the Ottowia-related strains) might also have had a significant impact on the structure of the activated sludge due to their floc-forming abilities.

  4. Digital image processing and analysis for activated sludge wastewater treatment. (United States)

    Khan, Muhammad Burhan; Lee, Xue Yong; Nisar, Humaira; Ng, Choon Aun; Yeap, Kim Ho; Malik, Aamir Saeed


    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.

  5. Assessing the diurnal variability of pharmaceutical and personal care products in a full-scale activated sludge plant

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, R. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); ESTS-IPS, Escola Superior de Tecnologia de Setubal do Instituto Politecnico de Setubal, Rua Vale de Chaves, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); Marques, R. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnologica (IBET), Av. da Republica (EAN), 2784-505 Oeiras (Portugal); Noronha, J.P. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Mexia, J.T. [Center of Mathematic Applications, Mathematics Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Carvalho, G. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnologica (IBET), Av. da Republica (EAN), 2784-505 Oeiras (Portugal); Oehmen, A., E-mail: [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Reis, M.A.M. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)


    An intensive sampling campaign has been carried out in a municipal wastewater treatment plant (WWTP) to assess the dynamics of the influent pharmaceutical active compounds (PhAC) and musks. The mass loadings of these compounds in wastewater influents displayed contrasting diurnal variations depending on the compound. The musks and some groups of PhACs tended to follow a similar diurnal trend as compared to macropollutants, while the majority of PhACs followed either the opposite trend or no repeatable trend. The total musk loading to the WWTP was 0.74 {+-} 0.25 g d{sup -1}, whereas the total PhAC mass loading was 84.7 {+-} 63.8 g d{sup -1}. Unlike the PhACs, the musks displayed a high repeatability from one sampling day to the next. The range of PhAC loadings in the influent to WWTPs can vary several orders of magnitude from one day or week to the next, representing a challenge in obtaining data for steady-state modelling purposes. - Highlights: > Investigated the variations in influent wastewater pharmaceutical and musk loadings. > A high number of different pharmaceutical and musk compounds was analysed. > Many pharmaceutical groups displayed different characteristic patterns. > A representative steady-state pattern was observable for musks, not pharmaceuticals. > The results are relevant to the design of sampling campaigns for modelling purposes. - The diurnal variations of pharmaceuticals and musks were studied in an activated sludge plant, where the loadings of the musks were more repeatable than the pharmaceuticals.

  6. Sludge Hygienization Plant with Electron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin-Kyu; Kim, Yuri; Han, Bumsoo [EB TECH CO., LTD., Daejeon (Korea, Republic of); Yaacob, Nitzan Ben [Bar Idan Ltd., Shimshit (Israel)


    The sludge resulting from municipal wastewater treatment can be used as a soil conditioner. However, it contains bacteria and other micro-organisms, and should be disinfected prior to use. Ionizing Radiation has the ability to inactivate the pathogens with a very high degree of reliability. Accelerated electrons interact with matters, thus causing cell death. Digested sludge from municipal wastewater treatment plant has been used directly for agriculture in Israel, however, owing to the infection by pathogenic microorganisms, the sludge must be processed to reduce the number of pathogens, and the radiation is the solution. An industrial scale plant with the capacity to treat 5 m{sup 3} of dewatered sludge per hour (18% solid contents) with 10 kGy has been planned in municipal wastewater treatment facility Bet Shemesh. This plant will be equipped with an electron accelerator (1.5MeV, 20kW) and handling facilities, and is expected to be more economical than other sludge disposal processes, such as incineration, lime stabilization, etc.

  7. Degradation of polycyclic aromatic hydrocarbons by Pseudomonas sp.JM2 isolated from active sewage sludge of chemical plant

    Institute of Scientific and Technical Information of China (English)

    Jing Ma; Li Xu; Lingyun Jia


    It is important to screen strains that can decompose polycyclic aromatic hydrocarbons (PAHs) completely and rapidly with good adaptability for bioremediation in a local area.A bacterial strain JM2,which uses phenanthrene as its sole carbon source,was isolated from the active sewage sludge from a chemical plant in Jilin,China and identified as Pseudomonas based on 16S rDNA gene sequence analysis.Although the optimal growth conditions were determined to be pH 6.0 and 37℃,JM2 showed a broad pH and temperature profile.At pH 4.5 and 9.3,JM2 could degrade more than 40% of fluorene and phenanthrene (50 mg/L each) within 4 days.In addition,when the temperature was as low as 4℃,JM2 could degrade up to 24% fluorene and 12% phenanthrene.This showed the potential for JM2 to be applied in bioremediation over winter or in cold regions.Moreover,a nutrient augmentation study showed that adding formate into media could promote PAH degradation,while the supplement of salicylate had an inhibitive effect.Furthermore,in a metabolic pathway study,salicylate,phthaiic acid,and 9-fluorenone were detected during the degradation of fluorene or phenanthrene.In conclusion,Pseudomonas sp.JM2 is a high performance strain in the degradation of fluorene and phenanthrene under extreme pH and temperature conditions.It might be useful in the bioremediation of PAHs.

  8. Activated Sludge Ozonation to Reduce Sludge Production in MBR

    Institute of Scientific and Technical Information of China (English)

    HE Sheng-bing; XUE Gang; WANG Bao-zhen


    The total experimental period was divided into two stages.At the first stage, a series of batch studies were carried out to get an understanding of the effect of ozonation on sludge properties. At the following stages, three MBRs with different amounts of activated sludge to be ozonated were run in parallel for a long period to evaluate the influence of sludge ozonation on sludge yield and permeate quality.Through batch study, it was found that ozone could disrupt the cell walls and caused the release of plasm from the cells,then the amounts of soluble organics in the solution increased with ozonation time. With the rise of soluble organics, the amount of soluble organics to be mineralized increased as well, which wonld reduce the soluble organics content. For the counteraction between these two aspects, a pseudo-balance could be achieved, and soluble organics would vary in a limited range. Sludge ozonation also increased the contents of nitrogen and phosphorus in the solution. In addition, ozonation was effective in improving sludge settling property. On the basis of batch study, a suitable ozone dosage of 0.16 kgO3/kgMLSS wasdetermined. Three systems were run in parallel for a total period of 39 days, it was demonstrated that a part of activated sludge ozonation could reduce sludge production significantly, and biological performance of mineralization and nitrification would not be inhibited due to sludge ozonation. Experimental results proved that the combination of ozonation unit with MBR unit could achieve an excellent quality of permeate as well as a small quantity of sludge production, and economic analysis indicated that an additional ozonation operating cost for treatment of both wastewater and sludge was only 0.096Yuan (US $0.011,5)/m3 wastewater.

  9. Activated sludge wastewater treatment plant modelling and simulation: state of the art

    DEFF Research Database (Denmark)

    Gernaey, Krist; Loosdrecht, M.C.M. van; Henze, Mogens


    included in white-box models with predictions based on data in areas where the white-box model assumptions are not valid or where white-box models do not provide accurate predictions. Artificial intelligence (Al) covers a large spectrum of methods. and many of them have been applied in applications related......This review paper focuses on modelling of wastewater treatment plants (WWTP). White-box modelling is widely applied in this field, with learning, design and process optimisation as the main applications. The introduction of the ASM model family by the IWA task group was of great importance...

  10. Enhancement of activated sludge disintegration and dewaterability by Fenton process (United States)

    Heng, G. C.; Isa, M. H.


    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.


    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Le-Quy, Vang; Nielsen, Kåre Lehmann;

    and when external carbon sources were supplemented to the activated sludge the composition of the denitrifying communities was significantly affected. Transcriptome profiling provided detailed insight in the metabolic pathways in several of the active denitrifiers in activated sludge. In conclusion...... reactor studies. To obtain better identification of active denitrifying communities in full-scale wastewater treatment plants (WWTPs) we applied DNA-SIP with 13C-labelled substrates, and RT-PCR of expressed denitrification genes (nirS, nirK and nosZ) upon various substrate-inductions. To come around...... were determined with quantitative FISH, while their active metabolic pathways were investigated directly in activated sludge with a tag-based metatranscriptomic approach under acetate-utilizing and denitrifying conditions. The different methods revealed a majority of denitrifiers in all WWTPs belonging...

  12. A simple empirical model for activated sludge thickening in secondary clarifiers. (United States)

    Giokas, D L; Kim, Youngchul; Paraskevas, P A; Paleologos, E K; Lekkas, T D


    A simple empirical model for the thickening function of the activated sludge secondary clarifiers is presented. The proposed approach relies on the integration of previous models and it is based on the phenomenon of dilution of the incoming activated sludge in the feeding well of the settling tanks. The method provides a satisfactory description of sludge stratification within the clarifier. The only requirements are limited to parameters which are readily incorporated into the routine analysis performed in an activated sludge plant, thereby eliminating the need for additional experimental or computational effort. The method was tested in a full-scale activated sludge plant and it was found that it describes fairly well the return sludge concentration, the diluted sludge blanket concentration, the sludge blanket solids concentration and the sludge blanket height of full-scale secondary clarifiers.

  13. Surrogate parameters for rapid monitoring of contaminant removal for activated sludge treatment plants for para rubber and seafood industries in Southern Thailand

    Directory of Open Access Journals (Sweden)

    Panalee Chevakidagarn


    Full Text Available This study aimed at using surrogate parameters for rapid monitoring of contaminant removed of activated sludge treatment plant for para rubber and seafood industries in Southern Thailand. Wastewaters from these industries contain high organic concentrations and chemicals. The activated sludge process (AS is usually applied as a treatment process. However, plant operators generally lack the understanding and means to control the treatment plants because of a continuous monitoring system is not employed and the monitoring parameters are time consuming. UV absorbency at various wavelengths was used in this study as a surrogate parameters, for predicting the removal capacity of each plant. COD, BOD, suspended solids and nitrate-nitrogen concentrations could be estimated reliably without being time consuming. The results showed that UV absorbency at 220 nm can be used as a parameter to predict nitrate-nitrogen concentrations which less than 15 mg/L. That at 550 nm is for predicting suspended solids concentration and that at 260 nm is for COD predict.

  14. Taxonomy and Physiology of un-wanted bacterial flora in activated sludge process. Study in a pilot plant; Taxonomia y fisiologia de la flora bacteriana indeseable en el proceso de fangos activados. Estudio de una plant piloto

    Energy Technology Data Exchange (ETDEWEB)

    Berrocal Escobar, M.; Lopez Fernandez, C. L.; Arias Fernandez, M. E.; Perez Leblic, M. I.; Zapatero Martin, I.; Leton Garcia, P.; Garcia Calvo, E. [Universidad de Alcala de Henares. Madrid (Spain); Aznar Munoz, R.; Rodriguez Medina, P. [Departamento Tecnico y de Calidad de Seragua, S.A. Madrid (Spain)


    The activated sludge used in the wastewater depuration in treatment plants could be considered as an artificial microbial ecosystem in balance. In this community which is constituted by free and flocculated bacteria, protozoa, rotifers, nematodes and a few other invertebrates, the stability of the system is maintained by the continuous food competition. The breakdown of this stability due to a high proliferation of filametous bacteria drive to the phenomenon called bulking. Nowadays, to avoid bulking is one of the main objectives in research because is the main cause of the malfunction of wastewater depuration interfering with compaction, settling, thickening and, concentration of activated sludge. In the present work, a taxonomical and physiological study of the microbial community which carries out the cleaning of wastewater in an activated sludge system has been performed by using an airlift bioreactor working in continuous. Activated sludge coming from a conventional wastewater plant was used as inoculum (starter culture). The nutritional conditions and bioreactor system parameters in which the filamentous bacteria grow in excess have been established. Several of filamentous bacteria responsible for bulking have been identified: Sphaerotilus natans, type 021N, Nocardia spp., Microthrix parvicella, Thiotrix I, Thiotrix II, type 0803, type 0581, Nostocoida limicola I and III and, type 1863. In addition, protozoa of groups involved in the depuration process (free-swimming ciliates, attached ciliates, crawling ciliates, carnivorous ciliates, flagellates and amoebae) were observed as well as rotifer and nematode populations. (Author) 13 refs.

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

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard


    and dissolved extracellular polymeric substances (EPS). Polyvalent ions improve the floc strangth and improve the separation whereas monovalent ions (e.g. from road salt, sea water intrusion and industry) reduces impair the separation. Further high pH impairs the separation process due to floc disintegration......Solid-liquid separation of activated sludge is important both directly after the biological treatment of wastewater and for sludge dewatering. The separation of solid from the treated wastewater can be done by clarifiers (conventional plants) or membrane (MBR). Further, part of the sludge is taken...

  16. The Microbiota and Abundance of the Class 1 Integron-Integrase Gene in Tropical Sewage Treatment Plant Influent and Activated Sludge.

    Directory of Open Access Journals (Sweden)

    Magna C Paiva

    Full Text Available Bacteria are assumed to efficiently remove organic pollutants from sewage in sewage treatment plants, where antibiotic-resistance genes can move between species via mobile genetic elements known as integrons. Nevertheless, few studies have addressed bacterial diversity and class 1 integron abundance in tropical sewage. Here, we describe the extant microbiota, using V6 tag sequencing, and quantify the class 1 integron-integrase gene (intI1 in raw sewage (RS and activated sludge (AS. The analysis of 1,174,486 quality-filtered reads obtained from RS and AS samples revealed complex and distinct bacterial diversity in these samples. The RS sample, with 3,074 operational taxonomic units, exhibited the highest alpha-diversity indices. Among the 25 phyla, Proteobacteria, Bacteroidetes and Firmicutes represented 85% (AS and 92% (RS of all reads. Increased relative abundance of Micrococcales, Myxococcales, and Sphingobacteriales and reduced pathogen abundance were noted in AS. At the genus level, differences were observed for the dominant genera Simplicispira and Diaphorobacter (AS as well as for Enhydrobacter (RS. The activated sludge process decreased (55% the amount of bacteria harboring the intI1 gene in the RS sample. Altogether, our results emphasize the importance of biological treatment for diminishing pathogenic bacteria and those bearing the intI1 gene that arrive at a sewage treatment plant.


    Directory of Open Access Journals (Sweden)



    Full Text Available Fresh activated sludge in many wastewater treatment plants may be considered unhealthy due to the large amount of organic and organism content. Due to the lack of research on municipal sludge, there is an apparent scarcity of actual data. Thus, this work will focus on the characterization of fresh activated sludge. The effect of dosage of different polyelectrolytes and coagulants has been investigated at pH level in a comparative fashion that is commonly associated with fresh activated sludge. The results indicated that the cationic polyelectrolytes had significant effluence on the sludge properties, degree of flocculation and water quality. With respect to the optical analyses, it was observed that the floc sizes and densities were increased with rise concentrations of both types of cationic polyelectrolytes. It was found that the cationic CPAM-80 was the most effective chemical among other six used chemicals especially for solutions with pH near neutrality despite of the variations in feed properties of the fresh activated sludge. This polyelectrolyte gave lower turbidity, lower sludge volume index, faster zone settling rate and large floc density.

  18. Thermo-Oxidization of Municipal Wastewater Treatment Plant Sludge for Production of Class A Biosolids (United States)

    Bench-scale reactors were used to test a novel thermo-oxidation process on municipal wastewater treatment plant (WWTP) waste activated sludge (WAS) using hydrogen peroxide (H2O2) to achieve a Class A sludge product appropriate for land application. Reactor ...

  19. Effect of microwave pre-treatment of thickened waste activated sludge on biogas production from co-digestion of organic fraction of municipal solid waste, thickened waste activated sludge and municipal sludge. (United States)

    Ara, E; Sartaj, M; Kennedy, K


    Anaerobic co-digestion of organic fraction of municipal solid waste, with thickened waste activated sludge and primary sludge has the potential to enhance biodegradation of solid waste, increase longevity of existing landfills and lead to more sustainable development by improving waste to energy production. This study reports on mesophilic batch and continuous studies using different concentrations and combinations (ratios) of organic fraction of municipal solid waste, thickened waste activated sludge (microwave pre-treated and untreated) and primary sludge to assess the potential for improved biodegradability and specific biogas production. Improvements in specific biogas production for batch assays, with concomitant improvements in total chemical oxygen demand and volatile solid removal, were obtained with organic fraction of municipal solid waste:thickened waste activated sludge:primary sludge mixtures at a ratio of 50:25:25 (with and without thickened waste activated sludge microwave pre-treatment). This combination was used for continuous digester studies. At 15 d hydraulic retention times, the co-digestion of organic fraction of municipal solid waste:organic fraction of municipal solid waste:primary sludge and organic fraction of municipal solid waste:thickened waste activated sludge microwave:primary sludge resulted in a 1.38- and 1.46-fold increase in biogas production and concomitant waste stabilisation when compared with thickened waste activated sludge:primary sludge (50:50) and thickened waste activated sludge microwave:primary sludge (50:50) digestion at the same hydraulic retention times and volumetric volatile solid loading rate, respectively. The digestion of organic fraction of municipal solid waste with primary sludge and thickened waste activated sludge provides beneficial effects that could be implemented at municipal wastewater treatment plants that are operating at loading rates of less than design capacity.

  20. Bioindicators in the activated sludge reactors in the Guadalete Waste Water Plant; Bioindicadores en los reactores de fangos activados en la EDAR Guadalete

    Energy Technology Data Exchange (ETDEWEB)

    Narbona Valle, E. M.; Isac Oria, L.; Lebrato Mtnez, J.; Martinez, A. [Universidad Politecnica . Sevilla (Spain)


    The bioindication, the technique based on the microscopic observations on the activated sludge, is a useful tool to control the biologic depuration process. The affectivity of this technique can be shown through its application in the study of a stable activated sludge process, which doesn't show strong changes in its operational parameters. Some of the observed microorganisms will be used like indicators of the state of the process and the quality of the effluent. (Author) 10 refs.

  1. Correlation between Microbial Quality and Organic Content in the Effluent of an Activated Sludge Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Mostafaii Gh.R.1 PhD,


    Full Text Available Aims Regarding water as the main source of brio, not only its quantity and being availability is vital, but also its quality must be considered. This study was done in order to determine the correlation between physicochemical BOD5 and microbiological parameters (FC and TC in the Kashan University of Medical Sciences wastewater effluent of activated sludge system. Materials & Methods This descriptive study was done from July to October 2012 at Kashan University of Medical Sciences. A total number of 130 samples were taken on different days of the week over a 4-month period from effluent, randomly. All of the taken samples were transferred to the water and wastewater laboratory for analysis, immediately. The SPSS 16 software and regression test for were used to analyze the obtained data, ultimately. Findings The mean value for BOD5 was 11.27±5.43mgL1. The mean value of TC was log1.62±0.32. A linear correlation (F=312.9 ;p<0.001 was observed between TC and BOD5. The mean value of FC was log1.42±0.31. A linear correlation (F=298.3 ;p<0.001 was observed between FC and BOD5. Conclusion BOD5 parameter can be used to predict the wastewater quality instead of TC and FC.

  2. Genomic and in situ investigations of the novel uncultured Chloroflexi associated with 0092 morphotype filamentous bulking in activated sludge

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Karst, Søren Michael; Nierychlo, Marta;


    Overgrowth of filamentous bacteria in activated sludge wastewater treatment plants (WWTPs) leads to impaired sludge settleability, a condition known as bulking, which is a common operational problem worldwide. Filaments with the Eikelboom 0092 morphotype are commonly associated with such bulking...

  3. Fertilization value of municipal sewage sludge for Eucalyptus camaldulensis plants

    Directory of Open Access Journals (Sweden)

    Soudani Leila


    Full Text Available The wastewater treatment produces a large amount of sludge. The different uses of eliminations sludge such as landfills or incineration have consequences negative for the environment, the agricultural use has increased worldwide, especially in crops and few or no studies have been conducted with forest plantations in Algeria. The objective of this study is to assess fertilizing characteristics of the sludge from the wastewater treatment plant of Tiaret (Algeria. One-year-old saplings of Eucalyptus camaldulensis were transplanted into pots with sludge/soil mixtures where sludge content was 20%, 40% and 60%. Biometric measurements (height, base diameter, diameter at mid-height and the number of leaves were performed during six months after planting. Results demonstrated the positive effect of sludge application. A significant difference in height increment and number of leaves was found between the control and sludge-treated plants. Biometric values for all sludge mixtures were higher than those for control plants (100% soil. The mixture, which contained 60% sludge, gives the best result, except for a diameter of stem. Plants grown on sludge/soil mixture had average height 49.4 ± 24.1 cm and average number of leaves 68.8 ± 6.2 while average height for plants grown on soil was 34.3 ± 12.8 cm and average number of leaves was 40 ± 3.8. Sludge application provides soil amendment and additional nutrient supply for planted trees.

  4. Reduction by sonication of excess sludge production in a conventional activated sludge system: continuous flow and lab-scale reactor. (United States)

    Vaxelaire, S; Gonze, E; Merlin, G; Gonthier, Y


    Conventional activated sludge wastewater treatment plants currently produce a large quantity of excess sludge. To reduce this sludge production and to improve sludge characteristics in view of their subsequent elimination, an ultrasonic cell disintegration process was studied. In a lab-scale continuous flow pilot plant, part of the return sludge was sonicated by low-frequency and high-powered ultrasound and then recycled to the aeration tank. Two parallel lines were used: one as a control and the other as an assay with ultrasonic treatment. The reactors were continuously fed with synthetic domestic wastewater with a COD (chemical oxygen demand) of approximately 0.5 g l(-) corresponding to a daily load of 0.35-0.50 kg COD kg(-1) TS d(-1). Removal efficiencies (carbon, particles), excess sludge production and sludge characteristics (particle size distribution, mineralization, respiration rate, biological component) were measured every day during the 56-day experiment. This study showed that whilst organic removal efficiency did not deteriorate, excess sludge production was decreased by about 25-30% by an ultrasonic treatment. Several hypotheses are advanced: (i) the treatment made a part of the organic matter soluble as a consequence of the floc disintegration, and optimised the conversion of the carbonaceous pollutants into carbon dioxide and (ii) the treatment modified the physical characteristics of sludge by a mechanical effect: floc size was reduced, increasing the exchange surface and sludge activity. The originality of this study is that experiments were conducted in a continuous-flow activated sludge reactor rather than in a batch reactor.

  5. Analysis and modelling of predation on biofilm activated sludge process: Influence on microbial distribution, sludge production and nutrient dosage. (United States)

    Revilla, Marta; Galán, Berta; Viguri, Javier R


    The influence of predation on the biofilm activated sludge (BAS) process is studied using a unified model that incorporates hydrolysis and predation phenomena into the two stages of the BAS system: moving bed biofilm reactor pre-treatment (bacterial-predator stage) and activated sludge (predator stage). The unified model adequately describes the experimental results obtained in a cellulose and viscose full-scale wastewater plant and has been used to evaluate the role and contribution of predator microorganisms towards removal of COD, nutrient requirements, sludge production and microbial distribution. The results indicate that predation is the main factor responsible for the reduction of both nutrient requirements and sludge production. Furthermore, increasing the sludge retention time (SRT) does not influence the total biomass content in the AS reactor of a BAS process in two different industrial wastewater treatments.

  6. Excess sludge reduction in activated sludge processes by integrating ultrasound treatment

    Energy Technology Data Exchange (ETDEWEB)

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


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

  7. Comparison of membrane fouling during short-term filtration of aerobic granular sludge and activated sludge

    Institute of Scientific and Technical Information of China (English)


    Aerobic granular sludge was cultivated adopting internal-circulate sequencing batch airlift reactor. The contradistinctive experiment about short-term membrane fouling between aerobic granular sludge system and activated sludge system were investigated. The membrane foulants was also characterized by Fourier Transform Infrared (FTIR) spectroscopy technique. The results showed that the aerobic granular sludge had excellent denitrification ability; the removal efficiency of TN could reach 90%. The aerobic granular sludge could alleviate membrane fouling effectively. The steady membrane flux of aerobic granular sludge was twice as much as that of activated sludge system. In addition, it was found that the aerobic granular sludge could result in severe membrane pore-blocking, however, the activated sludge could cause severe cake fouling. The major components of the foulants were identified as comprising of proteins and polysaccharide materials.

  8. Sludge Reduction by Lumbriculus Variegatus in Ahvaz Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Tim Hendrickx


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

  9. Sequential modeling of fecal coliform removals in a full-scale activated-sludge wastewater treatment plant using an evolutionary process model induction system. (United States)

    Suh, Chang-Won; Lee, Joong-Won; Hong, Yoon-Seok Timothy; Shin, Hang-Sik


    We propose an evolutionary process model induction system that is based on the grammar-based genetic programming to automatically discover multivariate dynamic inference models that are able to predict fecal coliform bacteria removals using common process variables instead of directly measuring fecal coliform bacteria concentration in a full-scale municipal activated-sludge wastewater treatment plant. A sequential modeling paradigm is also proposed to derive multivariate dynamic models of fecal coliform removals in the evolutionary process model induction system. It is composed of two parts, the process estimator and the process predictor. The process estimator acts as an intelligent software sensor to achieve a good estimation of fecal coliform bacteria concentration in the influent. Then the process predictor yields sequential prediction of the effluent fecal coliform bacteria concentration based on the estimated fecal coliform bacteria concentration in the influent from the process estimator with other process variables. The results show that the evolutionary process model induction system with a sequential modeling paradigm has successfully evolved multivariate dynamic models of fecal coliform removals in the form of explicit mathematical formulas with high levels of accuracy and good generalization. The evolutionary process model induction system with sequential modeling paradigm proposed here provides a good alternative to develop cost-effective dynamic process models for a full-scale wastewater treatment plant and is readily applicable to a variety of other complex treatment processes.

  10. Aerobic storage under dynamic conditions in activated sludge processes

    DEFF Research Database (Denmark)

    Majone, M.; Dircks, K.


    In activated sludge processes, several plant configurations (like plug-flow configuration of the aeration tanks, systems with selectors, contact-stabilization processes or SBR processes) impose a concentration gradient of the carbon sources to the biomass. As a consequence, the biomass grows under...... mechanisms can also contribute to substrate removal, depending on the microbial composition and the previous "history" of the biomass. In this paper the type and the extent of this dynamic response is discussed by review of experimental studies on pure cultures, mixed cultures and activated sludges...... and with main reference to its relevance on population dynamics in the activated sludge. Possible conceptual approaches to storage modelling are also presented, including both structured and unstructured modelling. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved....

  11. Polyhydroxyalkanoate production potential of heterotrophic bacteria in activated sludge. (United States)

    Inoue, Daisuke; Suzuki, Yuta; Uchida, Takahiro; Morohoshi, Jota; Sei, Kazunari


    This study was conducted to evaluate the polyhydroxyalkanoate (PHA) production potential of cultivable heterotrophic bacteria in activated sludge by genotypic and phenotypic characterizations. A total of 114 bacterial strains were isolated from four activated sludge samples taken from a lab-scale sequencing batch reactor and three wastewater treatment processes of two municipal wastewater treatment plants. PCR detection of the phaC genes encoding class I and II PHA synthase revealed that 15% of the total isolates possessed phaC genes, all of which had the closest similarities to known phaC genes of α- and β-Proteobacteria and Actinobacteria. PHA production experiments under aerobic and nitrogen-limited conditions showed that 68% of the total isolates were capable of producing PHA from at least one of the six substrates used (acetate, propionate, lactate, butyrate, glucose and glycerol). Genotypic and phenotypic characterizations revealed that 75% of the activated sludge bacteria had PHA production potential. Our results also indicated that short-chain fatty acids would be the preferable substrates for PHA production by activated sludge bacteria, and that there might be a variety of unidentified phaC genes in activated sludge.

  12. Anaerobic bioleaching of metals from waste activated sludge

    Energy Technology Data Exchange (ETDEWEB)

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


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

  13. A quick system for estimating the purification performance of waste water treatment plants based on the macroscopic and microscopic characteristics of activated sludge; Sistema rapido de estimacion de los rendimientos en depuracion de una EDAR en funcion de las caracteristicas macroscopicas del fango activado

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, C.; Fernandez, N.; Horra de la, J. M.; Rodriguez, E.; Isac, L.; Salas, D.; Gomez, E.; Ortiz Vargas, A.; Gonzalez Carballo, J. A.


    Microbiological studies of activated sludge require time, specialized staff and the arduous task of identifying and analysing the results, which is not usually within the scope of every laboratory. This article raises the possibility of carrying out a simplified study of active sludge, based on its macroscopic and microscopic characteristics, which produces a sludge index value that is directly related to the percentage reduction of solids in suspension, COD and BOD in the waste water treatment plant. In addition, this sludge index would also provide the possibility of quickly obtaining a historical record of biological quality values using a simple protocol that could be use for comparisons. (Author) 10 refs.

  14. Anaerobic bioleaching of metals from waste activated sludge

    KAUST Repository

    Meulepas, Roel J W


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

  15. Modelling of the Secondary Clarifier Combined with the Activated Sludge Model no. 1

    DEFF Research Database (Denmark)

    Dupont, René; Henze, Mogens


    Modelling of activated sludge wastewater treatment plants is today generally based on the Activated Sludge Model No. 1 combined with a very simple model for the secondary settler. This paper describes the development of a model for the secondary clarifier based on the general flux theory for zone...

  16. Accurate assessment of the biodegradation of cationic surfactants in activated sludge reactors (OECD TG 303A)

    NARCIS (Netherlands)

    Geerts, R.; Ginkel, van C.G.; Plugge, C.M.


    The continuous-fed activated sludge test (OECD TG 303A) was used to predict the removal of cationic surfactants from wastewater in activated sludge plants. However, a method to differentiate between adsorption and biodegradation is not provided in these guidelines. Assessment of removal by biodegrad

  17. Lipase and protease extraction from activated sludge

    DEFF Research Database (Denmark)

    Gessesse, Amare; Dueholm, Thomas; Petersen, Steffen B.


    of gentle and efficient enzyme extraction methods from environmental samples is very important. In this study we present a method for the extraction of lipases and proteases from activated sludge using the non-ionic detergent Triton X-100, EDTA, and cation exchange resin (CER), alone or in combination...... for the extraction of lipases and proteases from activated sludge. The sludge was continuously stirred in the presence of either buffer alone or in the presence of detergent and/or chelating agents. In all cases, a marked reduction in floc size was observed upon continuous stirring. However, no lipase activity...... and negligible protease activity was extracted in the presence of buffer alone, indicating that enzyme extraction was not due to shear force alone. The highest lipase activity was extracted using 0.1% Triton X-100 above which the activity was gradually decreasing. For proteases, the highest activity was obtained...

  18. Avaliação das unidades de tratamento do lodo em uma ete de lodos ativados convencional submetida a distintas estratégias operacionais Evaluation of the sludge treatment units in an activated sludge treatment plant subjected to different operational strategies

    Directory of Open Access Journals (Sweden)

    Alessandra Valadares Álvares da Silva


    Full Text Available A finalidade deste trabalho é apresentar uma avaliação da etapa de tratamento de lodos da Estação de Tratamento de Esgotos do Arrudas (Belo Horizonte, em especial os teores de sólidos ao longo do sistema, as principais variáveis de projeto e operação. O processo de tratamento é o de lodos ativados convencional com adensamento por gravidade, digestão anaeróbia e desidratação mecânica. Desde sua entrada em operação até o momento, a estação passou por três fases operacionais quanto ao adensamento dos lodos. A maior concentração média do lodo primário (4,8% foi atingida no adensador por gravidade quando esse recebia apenas lodo primário. O lodo misto alcançou uma concentração média de 2,7% enquanto o valor esperado de projeto era 5,0%. O lodo secundário excedente, concentrado no adensador por gravidade não ultrapassou 1,8%. A maior concentração média da torta do lodo desidratado (28,3% foi obtida quando o lodo digerido era proveniente do tratamento primário.This paper aims to evaluate the sludge treatment stage at the Arrudas Wastewater Treatment Plant (Belo Horizonte, Brazil, especially the solids contents throughout the sludge treatment line, as well as the main design and operating variables. The conventional activated sludge plant has a typical solids-line flowsheet: gravity thickening, anaerobic digestion and mechanical dewatering. Three main operational phases have been identified, whose implications in the plant behaviour are analysed in the paper. The highest concentration of primary sludge (mean value of 4.8% was reached in the gravitational thickening when it was fed with primary sludge only. The mixed sludge concentrated in the gravitational thickening reached only a mean concentration of 2.7%, whereas the expected result was 5.0%. The excess secondary sludge concentrated in the gravitational thickener did not reach 1.8%. The largest concentration of the dewatered sludge cake (means value of 28.3% was

  19. Toxicity measurement in a waste water treatment plants using active sludge aerobic biological treatment. Medida de la toxicidad en una estacion depuradora de aguas residuales con tratamiento biologico aerobio por fangos activos

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, J.E. (Surcis, Guadalajara (Spain))


    The need for reliability in the operation of waste water treatment plants is discussed. In aerobic biological treatments of whatever kind using active sludge, the bio toxicity can be determined by measuring the oxygen consumed in endogenous breathing. The difficulty lies in carrying out the bio toxicity test without effecting the concentration of the organic substrate of the wastes water. This is overcome by operating at maximum organic material load, thereby inducing maximun breathing. (Author)

  20. Extracellular polymers of ozonized waste activated sludge. (United States)

    Liu, J C; Lee, C H; Lai, J Y; Wang, K C; Hsu, Y C; Chang, B V


    Effect of ozonation on characteristics of waste activated sludge was investigated in the current study. Concentrations of cell-bound extracellular polymers (washed ECPs) did not change much upon ozonation, whereas the sum of cell-bound and soluble extracellular polymers (unwashed ECPs) increased with increasing ozone dose. Washed ECPs in original sludge as divided by molecular weight distribution was 39% 10,000 Da (high MW). It was observed that the low-MW fraction decreased, and the high-MW fraction increased in ozonized sludge. The unwashed ECPs were characterized as 44% in low MW, 30% in medium MW, and 26% in high MW. Both low-MW and medium-MW fractions of unwashed ECPs decreased while high-MW fraction increased in ozonized sludge. The dewaterability of ozonized sludge, assessed by capillary suction time (CST) and specific resistance to filtration (SRF), deteriorated with ozone dose. The optimal dose of cationic polyelectrolyte increased with increasing ozone dose. The production rate and the accumulated amount of methane gas of ozonized sludge were also higher.

  1. Dynamic modelling of solids in a full-scale activated sludge plant preceded by CEPT as a preliminary step for micropollutant removal modelling. (United States)

    Baalbaki, Zeina; Torfs, Elena; Maere, Thomas; Yargeau, Viviane; Vanrolleghem, Peter A


    The presence of micropollutants in the environment has triggered research on quantifying and predicting their fate in wastewater treatment plants (WWTPs). Since the removal of micropollutants is highly related to conventional pollutant removal and affected by hydraulics, aeration, biomass composition and solids concentration, the fate of these conventional pollutants and characteristics must be well predicted before tackling models to predict the fate of micropollutants. In light of this, the current paper presents the dynamic modelling of conventional pollutants undergoing activated sludge treatment using a limited set of additional daily composite data besides the routine data collected at a WWTP over one year. Results showed that as a basis for modelling, the removal of micropollutants, the Bürger-Diehl settler model was found to capture the actual effluent total suspended solids (TSS) concentrations more efficiently than the Takács model by explicitly modelling the overflow boundary. Results also demonstrated that particular attention must be given to characterizing incoming TSS to obtain a representative solids balance in the presence of a chemically enhanced primary treatment, which is key to predict the fate of micropollutants.

  2. Upgrading of an activated sludge wastewater treatment plant by adding a moving bed biofilm reactor as pre-treatment and ozonation followed by biofiltration for enhanced COD reduction: design and operation experience. (United States)

    Kaindl, Nikolaus


    A paper mill producing 500,000 ton of graphic paper annually has an on-site wastewater treatment plant that treats 7,240,000 m³ of wastewater per year, mechanically first, then biologically and at last by ozonation. Increased paper production capacity led to higher COD load in the mill effluent while production of higher proportions of brighter products gave worse biodegradability. Therefore the biological capacity of the WWTP needed to be increased and extra measures were necessary to enhance the efficiency of COD reduction. The full scale implementation of one MBBR with a volume of 1,230 m³ was accomplished in 2000 followed by another MBBR of 2,475 m³ in 2002. An ozonation step with a capacity of 75 kg O₃/h was added in 2004 to meet higher COD reduction demands during the production of brighter products and thus keeping the given outflow limits. Adding a moving bed biofilm reactor prior to the existing activated sludge step gives: (i) cost advantages when increasing biological capacity as higher COD volume loads of MBBRs allow smaller reactors than usual for activated sludge plants; (ii) a relief of strain from the activated sludge step by biological degradation in the MBBR; (iii) equalizing of peaks in the COD load and toxic effects before affecting the activated sludge step; (iv) a stable volume sludge index below 100 ml/g in combination with an optimization of the activated sludge step allows good sludge separation--an important condition for further treatment with ozone. Ozonation and subsequent bio-filtration pre-treated waste water provide: (i) reduction of hard COD unobtainable by conventional treatment; (ii) controllable COD reduction in a very wide range and therefore elimination of COD-peaks; (iii) reduction of treatment costs by combination of ozonation and subsequent bio-filtration; (iv) decrease of the color in the ozonated wastewater. The MBBR step proved very simple to operate as part of the biological treatment. Excellent control of the COD

  3. Calibration of the hydraulic model of a full-scale activated sludge plant; Calibracion hidraulica a escala real de un reactor de lodos activados

    Energy Technology Data Exchange (ETDEWEB)

    Fall, Cheikh [Universidad Autonoma del Estado de Mexico (Mexico); Loaiza-Navia, Jimmy [Servicios de Agua y Drenaje de Monterrey (Mexico)


    When planning to simulate a wastewater treatment plant (WWTP) with the activated sludge model number 1 (ASM1), one of the first requirements is to determine the hydraulic model of the reactor. The aim of this study was to evaluate the hydrodynamic regime of the aeration tank of a municipal WWTP by using a rhodamine tracer test and the Aquasim simulation software. A pre-simulation was performed in order to quantify the appropriate colorant mass, set up a sampling plan and evaluate the anticipated visual impact of the tracer test in the river receiving the treated effluents. A tracer test and dynamic flow measurements were carried out, the results of which served to establish and calibrate the hydraulic model. The evaluated tank was physically built as a plug-flow reactor subdivided in 7 compartments, but the study revealed that it is best represented by a model with 5 virtual mixed reactors in series. Through the study, the approach of using a WWTP simulator for hydraulics calibration was shown to be a powerful and flexible tool for designing a tracer test and for identifying adequate tank-in-series models of full-scale activated sludge aeration tanks. [Spanish] Cuando se planea simular una planta de tratamiento con base en el modelo numero 1 de lodos activados (ASM1), uno de los primeros requisitos es determinar el modelo hidraulico del reactor. En este trabajo se estudio el regimen hidrodinamico del tanque de accion de una planta de tratamiento de aguas residuales municipales (PTAR), utilizando una prueba de trazador con rodamina y un programa de simulacion (Aquasim). Se realizo una prueba de trazador con el experimento, lo que permitio determinar la cantidad requerida de trazador, fijar los intervalos de muestreo y limitar el impacto visual anticipado del colorante sobre el rio que recibe el efluente tratado. Se llevaron a cabo la prueba de trazador y la medicion de los perfiles dinamicos de caudales, cuyos resultados sirvieron para establecer y calibrar el

  4. Modelling of Activated Sludge Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Kurtanjeka, Ž.


    Full Text Available Activated sludge wastewater treatment is a highly complex physical, chemical and biological process, and variations in wastewater flow rate and its composition, combined with time-varying reactions in a mixed culture of microorganisms, make this process non-linear and unsteady. The efficiency of the process is established by measuring the quantities that indicate quality of the treated wastewater, but they can only be determined at the end of the process, which is when the water has already been processed and is at the outlet of the plant and released into the environment.If the water quality is not acceptable, it is already too late for its improvement, which indicates the need for a feed forward process control based on a mathematical model. Since there is no possibility of retracing the process steps back, all the mistakes in the control of the process could induce an ecological disaster of a smaller or bigger extent. Therefore, models that describe this process well may be used as a basis for monitoring and optimal control of the process development. This work analyzes the process of biological treatment of wastewater in the Velika Gorica plant. Two empirical models for the description of the process were established, multiple linear regression model (MLR with 16 predictor variables and piecewise linear regression model (PLR with 17 predictor variables. These models were developed with the aim to predict COD value of the effluent wastewater at the outlet, after treatment. The development of the models is based on the statistical analysis of experimental data, which are used to determine the relations among individual variables. In this work are applied linear models based on multiple linear regression (MLR and partial least squares (PLR methods. The used data were obtained by everyday measurements of the quantities that indicate the quality of the input and output water, working conditions of the plant and the quality of the activated sludge

  5. A procedure for benchmarking specific full-scale activated sludge plants used for carbon and nitrogen removal

    NARCIS (Netherlands)

    Abusam, A.; Keesman, K.J.; Spanjers, H.; Straten, van G.; Meinema, K.


    To enhance development and acceptance of new control strategies, a standard simulation benchmarking methodology to evaluate the performance of wastewater treatment plants has recently been proposed. The proposed methodology is, however, for a typical plant and typical loading and environmental condi


    This 92-page Technology Transfer Summary Report provides reference material on the causes and controls of sludge bulking and foaming in activated sludge treatment that can be readily understood, and it includes sufficient detail to help plant operators control their systems. The ...

  7. Ecological and kinetic aspects of amylolysis and proteolysis in activated sludge

    NARCIS (Netherlands)

    Janssen, J.M.A.


    An investigation has been made of the enzymic degradation of biopolymers by activated sludge. Starch was chosen as the model substrate; it was administered continuously at different sludge loading values which covered the entire range of loadings applied in sewage purification plants. The acclimatiz

  8. Plants grown on sewage sludge in South China and its relevance to sludge stabilization and metal removal

    Institute of Scientific and Technical Information of China (English)

    SAMAKE Moussa; WU Qi-Tang; MO Ce-hui; MOREL Jean-Louis


    The production of sewage sludge in China has been increasing sharply in order to treat 40% of the municipal sewage in 2005 as planned by central government. The main sludge disposal method is landfill owing to heavy metal contamination, but it presents an attractive potential for agricultural land application. Experiments were carried out to study the simultaneous metal removal and sludge stabilization by plants. The sludge samples were collected from Datansha Wastewater Treatment Plant of Guangzhou, it contained excessive Cu and Zn compared with the Chinese National Standard for Agricultural Use of Sewage Sludge. Plants growing on sludge beds were investigated to follow their growth and metal uptake. 30 sludge plants were identified during 1 year's observation. A Zn high-accumulating and high growth rate plant(Alocasia macrorrhiza) was selected and grown on sludge beds in plots. The water, organic matter, heavy metals and nutrients contents, the E. coli number and the cress seed germination index were monitored for the sludge samples collected monthly. The plant growth parameters and its heavy metals contents were also determined. The sewage sludge treated by plants could be stabilized at about 5 months, the E. coli number was significantly decreased and the cress seed germination index attained 100%. Crop on sludge could ameliorate the sludge drying. The experiments are continuing to find out the appropriate plant combination for simultaneous sludge stabilization and metal removal for an acceptable period. Comparisons between the proposed processes and other methods for treating produced sludge such as composting, chemical and bacterial leaching were discussed.

  9. Biodegradability of wastewater and activated sludge organics in anaerobic digestion. (United States)

    Ikumi, D S; Harding, T H; Ekama, G A


    The investigation provides experimental evidence that the unbiodegradable particulate organics fractions of primary sludge and waste activated sludge calculated from activated sludge models remain essentially unbiodegradable in anaerobic digestion. This was tested by feeding the waste activated sludge (WAS) from three different laboratory activated sludge (AS) systems to three separate anaerobic digesters (AD). Two of the AS systems were Modified Ludzack - Ettinger (MLE) nitrification-denitrification (ND) systems and the third was a membrane University of Cape Town (UCT) ND and enhanced biological P removal system. One of the MLE systems and the UCT system were fed the same real settled wastewater. The other MLE system was fed raw wastewater which was made by adding a measured constant flux (gCOD/d) of macerated primary sludge (PS) to the real settled wastewater. This PS was also fed to a fourth AD and a blend of PS and WAS from settled wastewater MLE system was fed to a fifth AD. The five ADs were each operated at five different sludge ages (10-60d). From the measured performance results of the AS systems, the unbiodegradable particulate organic (UPO) COD fractions of the raw and settled wastewaters, the PS and the WAS from the three AS systems were calculated with AS models. These AS model based UPO fractions of the PS and WAS were compared with the UPO fractions calculated from the performance results of the ADs fed these sludges. For the PS, the UPO fraction calculated from the AS and AD models matched closely, i.e. 0.30 and 0.31. Provided the UPO of heterotrophic (OHO, fE_OHO) and phosphorus accumulating (PAO, fE_PAO) biomass were accepted to be those associated with the death regeneration model of organism "decay", the UPO of the WAS calculated from the AS and AD models also matched well - if the steady state AS model fE_OHO = 0.20 and fE_PAO = 0.25 values were used, then the UPO fraction of the WAS calculated from the AS models deviated significantly

  10. Application of waterworks sludge in wastewater treatment plants

    DEFF Research Database (Denmark)

    Sharma, Anitha Kumari; Thornberg, D.; Andersen, Henrik Rasmus


    for removal of phosphate in the wastewater treatment was limited, because the dissolved iron in the digester liquid was limited by siderite (FeCO3) precipitation. It is concluded that both acidic and anaerobic dissolution of iron-rich waterworks sludge can be achieved at the wastewater treatment plant......The potential for reuse of iron-rich sludge from waterworks as a replacement for commercial iron salts in wastewater treatment was investigated using acidic and anaerobic dissolution. The acidic dissolution of waterworks sludge both in sulphuric acid and acidic products such as flue gas washing...

  11. Characteristics of sewage sludge and distribution of heavy metal in plants with amendment of sewage sludge

    Institute of Scientific and Technical Information of China (English)

    DAI Jia-yin; CHEN Ling; ZHAO Jian-fu; MA Na


    In order to better understand land application of sewage sludge, the characterization of heavy metals and organic pollutants were investigated in three different sewage sludges in Shanghai City, China. It was found that the total concentrations of Cd in all of sewage sludge and total concentrations of Zn in Jinshan sewage sludge, as well as those ofZn, Cu, and Ni in Taopu sludge are higher than Chinese regulation limit of pollutants for sludge to be used in agriculture. Leachability of Hg in all of studied samples and that of Cd in Taopu sewage sludge exceed the limit values of waste solid extraction standard in China legislation. Based on the characteristics for three kinds of sewage sludge, a pot experiment was conducted to investigate the effect of soil amended with Quyang sewage sludge on the accumulation of heavy metal by Begonia semperflorens-hybr; Ophiopogon japonicus (L.F.) Ker-Gaw; Loropetalum chindense-var. rubrum; Dendranthema morifolium; Viola tricolor; Antirrhinum majus; Buxus radicans Sieb; Viburnum macrocephalum;Osmanthus fragrans Lour; Cinnamomum camphora siebold and Ligustrum lucidum ait. Results showed that 8 species of plant survived in the amended soil, and moreover they flourished as well as those cultivated in the control soil. The heavy metal concentration in plants varied with species, As, Pb, Cd and Cr concentration being the highest in the four herbaceous species studied, particularly in the roots of D. morifolium. These plants, however, did not show accumulator of As, Pb, Cd and Cr. The highest concentration of Ni and Hg was found in the roots of D. morifolium, followed by the leaves orB. semperflorens-hybr. Levels of Zn and Cu were much higher in D. morifolium than in the other plant species. D. morifolium accumulated Ni, Hg, Cu and Zn, which may contribute to the decrease of heavy metal contents in the amended soil. Treatment with sewage sludge did not significantly affect the uptake of heavy metals by the L. chindense-var. rubrum

  12. Low intensity ultrasound stimulates biological activity of aerobic activated sludge

    Institute of Scientific and Technical Information of China (English)

    LIU Hong; YAN Yixin; WANG Wenyan; YU Yongyong


    This work aims to explore a procedure to improve biological wastewater treatment efficiency using low intensity ultrasound.The aerobic activated sludge from a municipal wastewater treatment plant was used as the experimental material.Oxygen uptake rate(OUR)of the activated sludge (AS)was determined to indicate the changes of AS activity stimulated by ultrasound at 35 kHZ for 0-40 min with ultrasonic intensities of 0-1.2 W/cm2.The highest OUR was observed at the ultrasonic intensity of 0.3 W/cm2 and an irradiation period of 10 min;more than 15% increase was achieved immediately after sonication.More significantly,the AS activity stimulated by ultrasound could last 24 h after sonication,and the AS activity achieved its peak value within 8 h after sonication.or nearly 100% higher than the initial level after sonication.Therefore,to improve the wastewater treatment efficiency of bioreactors,ultrasound with an intensity of 0.3 W/cm2 could be employed to irradiate a part of the AS in the bioreactor for 10 min every 8 h.

  13. The role of lipids in activated sludge floc formation

    Directory of Open Access Journals (Sweden)

    Anna Liza Kretzschmar


    Full Text Available Activated sludge is widely used to treat municipal and industrial wastewater globally and the formation of activated sludge flocculates (flocs underpins the ability to separate sludge from treated water. Despite the importance of activated sludge flocs to human civilization there have been precious few attempts to rationally design fit for purpose flocs using a bottom-up approach based on a solid scientific foundation. Recently we have been developing experimental models for activated sludge floc formation based on the colonization and consumption of particulate organic matter (chitin and cellulose. In this study we lay the foundation for investigation of activated sludge floc formation based on biofilm formation around spheres of the lipid glycerol trioleate (GT that form spontaneously when GT is introduced into activated sludge incubations. Sludge biomass was observed to associate tightly with the lipid spheres. An increase in extracellular lipase activity was associated with a decrease in size of the colonized lipid spheres over a 25 day incubation. Bacterial community composition shifted from predominantly Betaproteobacteria to Alphaproteobacteria in GT treated sludge. Four activated sludge bacteria were isolated from lipid spheres and two of them were shown to produce AHL like quorum sensing signal activity, suggesting quorum sensing may play a role in lipid spheres colonization and biodegradation in activated sludge. The development of this experimental model of activated sludge floc formation lays the foundation for rational production of flocs for wastewater treatment using lipids as floc nuclei and further development of the flocculate life-cycle concept.

  14. Effect of low temperature on highly unsaturated fatty acid biosynthesis in activated sludge. (United States)

    He, Su; Ding, Li-Li; Xu, Ke; Geng, Jin-Ju; Ren, Hong-Qiang


    Low temperature is a limiting factor for the microbial activity of activated sludge for sewage treatment plant in winter. Highly unsaturated fatty acid (UFA) biosynthesis, phospholipid fatty acid (PLFA) constituents and microbial structure in activated sludge at low temperature were investigated. Over 12 gigabases of metagenomic sequence data were generated with the Illumina HiSeq 2000 platform. The result showed 43.11% of phospholipid fatty acid (PLFA) in the activated sludge participated in UFA biosynthesis, and γ-Linolenic could be converted to Arachidonic acid at low temperature. The highly UFA biosynthesis in activated sludge was n-6 highly UFA biosynthesis, rather than n-3 highly UFA biosynthesis. The microbial community structures of activated sludge were analyzed by PLFA and high-throughput sequencing (HiSeq) simultaneously. Acidovorax, Pseudomonas, Flavobacterium and Polaromonas occupied higher percentage at 5°C, and genetic changes of highly UFA biosynthesis derived from microbial community structures change.

  15. Hydrogen sulphide removal by activated sludge diffusion. (United States)

    Barbosa, V L; Dufol, D; Callan, J L; Sneath, R; Stuetz, R M


    Odours from wastewater treatment plants comprise a mixture of various gases, of which hydrogen sulphide (H2S) is the main constituent. Microorganisms commonly found in wastewater can degrade sulphurous compounds. Therefore, the use of activated sludge (AS) for odour control offers an alternative to traditional waste gas treatment processes, such as biofilters, bioscrubbers and biotrickling filters, both in practical terms (use of existing facilities) and economically (minimal capital cost). The performance of AS diffusion as a bioscrubber for removing H2S at concentrations at 25, 75 and 150 ppmv was evaluated. Pilot-scale trials were undertaken using parallel 60-L aeration tanks and 20-L clarifier reactors at the Bedford Sewage Treatment Works, Carington, UK. Olfactometry measurements were also carried out to determine whether there was any increase in odour concentration owing to H2S diffusion. Hydrogen sulphide removal rates of 100% were obtained, with no noticeable increase in odour concentration throughout the trials as measured by olfactometry. Odour concentration was highest at the beginning of the trials and lowest during the high H2S dosing period, with similar values being obtained for test and control. It was concluded that AS diffusion is an effective bioscrubber for the removal of H2S odour.

  16. Interaction of operational and physicochemical factors leading to Gordonia amarae-like foaming in an incompletely nitrifying activated sludge plant. (United States)

    Asvapathanagul, Pitiporn; Huang, Zhonghua; Gedalanga, Phillip B; Baylor, Amber; Olson, Betty H


    The overgrowth of Gordonia amarae-like bacteria in the mixed liquor of an incompletely nitrifying water reclamation plant was inversely correlated with temperature (r = -0.78; P < 0.005) and positively correlated with the solids retention time (SRT) obtained a week prior to sampling (r = 0.67; P < 0.005). Drops followed by spikes in the food-to-mass ratio (0.18 to 0.52) and biochemical oxygen demand concentrations in primary effluent (94 to 298 mg liter(-1)) occurred at the initiation of G. amarae-like bacterial growth. The total bacterial concentration did not increase as concentrations of G. amarae-like cells increased, but total bacterial cell concentrations fluctuated in a manner similar to that of G. amarae-like bacteria in the pseudo-steady state. The ammonium ion removal rate (percent) was inversely related to G. amarae-like cell concentrations during accelerated growth and washout phases. The dissolved oxygen concentration decreased as the G. amarae-like cell concentration decreased. The concentrations of G. amarae-like cells peaked (2.47 × 10(9) cells liter(-1)) approximately 1.5 months prior to foaming. Foaming occurred during the late pseudo-steady-state phase, when temperature declines reversed. These findings suggested that temperature changes triggered operational and physicochemical changes favorable to the growth of G. amarae-like bacteria. Fine-scale quantitative PCR (qPCR) monitoring at weekly intervals allowed a better understanding of the factors affecting this organism and indicated that frequent sampling was required to obtain statistical significance with factors changing as the concentrations of this organism increased. Furthermore, the early identification of G. amarae-like cells when they are confined to mixed liquor (10(7) cells liter(-1)) allows management strategies to prevent foaming.

  17. Management experience on microthrix parvicella bulking in an activated sludge wastewater treatment plant; Esperienza di gestione del bulking filamentoso causato da microthrix parvicella in un impianto a biomassa sospesa

    Energy Technology Data Exchange (ETDEWEB)

    De Bortoli, N.; Mion, M. [AMGA S.p.A., Azienda Multiservizi, Udine (Italy); Di Giorgio, G.; Goi, D. [Udine Univ., Udine (Italy). Dipartimento di scienze e tecnologie chimiche


    Activated sludge wastewater treatment processes may give inefficiencies due to biological imbalances involving biomass. In fact, external causes as temperature lowering can increase the proliferation of the filamentous bacterium Microthrix parvicella into activated sludge flocks. Microthrix parvicella increases may create dangerous bulking phenomena compromising secondary settling without varying bio-kinetic parameters. In this case of study, a method to defeat growth of Microthrix parvicella has been set up. Aluminium poly-chloride (PAC) has been added to activated sludge contained into oxidation tanks of a municipal wastewater treatment plant, where a large growth of Microthrix parvicella has been periodically observed. It has been demonstrated that a definite PAC concentration can reduce Microthrix parvicella proliferation into activated sludge flocks so bulking phenomena can be well reduced. [Italian] I trattamenti di depurazione basati sulla tecnologia a biomassa sospesa possono essere soggetti a malfunzionamenti legati ad alterazioni degli equilibri biologici del complesso di microrganismi del fango attivo. In particolare, alcuni fattori esterni quali le basse temperature possono incrementare lo sviluppo del batterio filamentoso Microthrix parvicella, la cui eccessiva proliferazione nei fiocchi del fango attivo provoca pericolosi fenomeni di bulking filamentoso con peggioramento del processo di sedimentazione secondaria. La presenza di tali situazioni critiche puo non alterare necessariamente i parametri biocinetici principali del processo. Nella presente sperimentazione, condotta nelle vasche di un impianto di depurazione biologica di reflui urbani soggetto alla frequente proliferazione di Microthrix particella, si e voluto mettere in atto una procedura di controllo nei confronti dell'eccessiva crescita di tale specie batterica. E stata verificata l'utilita dell'impiego nel fango attivo del policloruro di alluminio (PAC) che, in opportune

  18. Automated monitoring of activated sludge using image analysis


    Motta, Maurício da; M. N. Pons; Roche, N; A.L. Amaral; Ferreira, E. C.; Alves, M.M.; Mota, M.; Vivier, H.


    An automated procedure for the characterisation by image analysis of the morphology of activated sludge has been used to monitor in a systematic manner the biomass in wastewater treatment plants. Over a period of one year, variations in terms mainly of the fractal dimension of flocs and of the amount of filamentous bacteria could be related to rain events affecting the plant influent flow rate and composition. Grand Nancy Council. Météo-France. Brasil. Ministério da Ciênc...

  19. Enhancement of sludge reduction and methane production by removing extracellular polymeric substances from waste activated sludge. (United States)

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


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

  20. High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation. (United States)

    Ekstrand, Eva-Maria; Karlsson, Marielle; Truong, Xu-Bin; Björn, Annika; Karlsson, Anna; Svensson, Bo H; Ejlertsson, Jörgen


    Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for the biogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibre sludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation. Two lab-scale reactors (4L) were run for 800days, one on fibre sludge (R1), and the other on fibre sludge and activated sludge (R2). Additions of Mg, K and S stabilized reactor performance. Furthermore, the Ca:Mg ratio was important, and a stable process was achieved at a ratio below 16:1. Foaming was abated by short but frequent mixing. Co-digestion of fibre sludge and activated sludge resulted in more robust conditions, and high-rate operation at stable conditions was achieved at an organic loading rate of 4g volatile solids (VS)L(-1)day(-1), a hydraulic retention time of 4days and a methane production of 230±10NmL per g VS.

  1. Diversity of foam producing nocardioform actinomycetes isolated from biological foam from activated sludge plants in Comunidad Valenciana; Diversidad de actinomicetos nocardioformes productores de espumas biologicas aislados de plantas depuradoras de aguas residuales de la Comunidad Valenciana

    Energy Technology Data Exchange (ETDEWEB)

    Soler, A.; Alonso, J.L.; Cuesta, G.


    The formation of biological foams in activated sludge systems is one of the most important problems of solid separation in wastewater treatment plants. Nocardioform actinomycetes are the most important filamentous bacteria responsible of foam formation. This group of microorganisms has hydrophobic cellular surfaces due to the mycolic acids. These foams interfere in wastewater treatment process because retain many suspended solids, block conductions and produce overflowing in the digesters and corridors. To identify correctly the nocardioform actinomycetes we have to do poli phasic taxonomy that includes 16S rDNA sequences analysis, determinate several chemo taxonomic markers and some phenotypic tests. (Author) 18 refs.

  2. Modelling of Activated Sludge Wastewater Treatment


    Kurtanjeka, Ž.; Deverić Meštrović, B.; Ležajić, Z.; Bevetek, A.; Čurlin; M.


    Activated sludge wastewater treatment is a highly complex physical, chemical and biological process, and variations in wastewater flow rate and its composition, combined with time-varying reactions in a mixed culture of microorganisms, make this process non-linear and unsteady. The efficiency of the process is established by measuring the quantities that indicate quality of the treated wastewater, but they can only be determined at the end of the process, which is when the water has already b...

  3. Activated Sludge Process Workshop Manual. (United States)

    Ontario Ministry of the Environment, Toronto.

    This manual was developed for use at workshops designed to upgrade the knowledge of experienced wastewater treatment plant operators. Each of the lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in this manual include: types and factors…

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  5. Toluene in sewage and sludge in wastewater treatment plants. (United States)

    Mrowiec, Bozena


    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.

  6. Adsorption characteristics of sulfide onto the activated sludge of municipal wastewater treatment plants. OUYAN G%城市污水处理厂污泥对水中硫化物的吸附特性

    Institute of Scientific and Technical Information of China (English)

    欧阳云; 席劲瑛; 王智超; 胡洪营


    为研究城市污水厂污泥对水中硫化物的吸附特性,从3座城市污水处理厂采集回流污泥,考察了硫化物浓度、温度、pH值和其他离子对污泥吸附硫化物的影响.结果表明,污水厂回流污泥对硫化物的吸附等温线可以用 Langmuir 方程很好地描述,其最大硫化物吸附量为15~27mg/g-干污泥.在温度为5~35℃条件下,吸附量随温度上升而增加,表明该吸附为吸热过程.pH值在2~7范围内,pH值对污泥吸附硫化物的影响不大,当pH值低于2时,污泥对硫化物的吸附量随pH降低显著减小.硫化物可能以离子形式被污泥吸附,该过程为化学吸附过程.水中存在0~25mg/L Cl-或0~12mg/L SO2-4不影响污泥对硫化物的吸附量.%In this study, activated sludge samples were collected from 3municipal wastewater treatment plants (WWTP) and the performance and impacting factors of sulfides adsorption onto the activated sludge were investigated. The impacting factors include sulfides concentration, temperature, pH and other anions. Adsorption isotherm of sulfide onto the activated sludge can be well described by Langmuir equation. The maximum sulfide adsorption capacity was 15~27mg/g-dry sludge. At the temperatures ranging from 5to 35℃, adsorption capacity increased by the rise in temperature and this implies the sulfides adsorption was an endothermic process. The pH value had little effect on the adsorption capacity from 2to 7. But the sulfides adsorption capacity decreased significantly when pH was lower than 2. Sulfides were adsorbed by activated sludge as anions (HS- and S2-) and it was a chemical adsorption process. Cl- ranging from 0 to 25mg/LorSO2- 4 ranging from 0 to 12mg/L did not affect the sulfides adsorption capacity.

  7. Detection of radionuclides originating from a nuclear power plant in sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Puhakainen, M.; Suomela, M


    Sewage sludge is a sensitive indicator of radionuclides entering the environment. Radionuclides originating in nuclear power stations have been detected in sludge found at wastewater treatment plants in communities near the power plants (NPP). The main contributor is the radionuclide discharges of the NPPs into the atmosphere, but workers may transmit small amounts through their clothes or skin, or from internal contamination. The purpose of the present investigation was to determine the amounts of radionuclides in sewage sludge and to obtain information on transport of the radionuclides from the NPPs to the wastewater treatment plants. Under normal operating conditions and during annual maintenance and refuelling outages at the Loviisa and Olkiluoto NPPs, sewage sludge samples were taken at wastewater treatment plants in communities located in the vicinity of the plants. With the exception of {sup 131}I, the most significant activities in discharges into the air from the Loviisa NPP were due to {sup 110}mAg. The latter was also noted most frequently in the sewage sludge at the wastewater treatment plant in the town of Loviisa about 10 km from the Loviisa pressurised water reactor (PWR) NPP. The other nuclides probably originating from the Loviisa NPP were {sup 51}Cr, {sup 54}Mn, {sup 58}Co, {sup 59}Fe, {sup 60}Co, {sup 110}mAg and {sup 124}Sb. In the wastewater treatment plant in the town of Rauma, about 10 km from the Olkiluoto boiling water reactor (BWR) NPP, the only nuclides possibly origination from the NPP were {sup 54}Mn, {sup 58}Co and {sup 60}Co. In the wastewater treatment plant, the variation in concentration of {sup 60}Co in sludge did not correlate with the activities measured in precipitation. The occurrence of the nuclide in the treatment plant did not correlate over time with the amounts of discharge from the NPP. This suggests that at least some of the activity was transported to the wastewater treatment plant via routes other than precipitation

  8. Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic-Anoxic-Aerobic Activated Sludge System. (United States)

    Zeng, Qingling; Li, Yongmei; Yang, Shijia


    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.

  9. The activated sludge bulking filament Eikelboom morphotype 0803 embraces more than one member of the Chloroflexi. (United States)

    Speirs, Lachlan B M; Tucci, Joseph; Seviour, Robert J


    The Eikelboom filamentous morphotype 0803 is commonly found in activated sludge systems globally, where it contributes to sludge bulking events. Earlier reports have suggested that it is a member of both the Proteobacteria and Chloroflexi. This study shows that this filament contributing to a period of poor sludge settleability in an Australian activated sludge plant is a member of the Chloroflexi, but not within the Caldilinea, as reported for this morphotype in Danish plants. Instead, it is a member of the Anaerolineae. The fluorescent signals generated in these filaments using the FISH probes designed here were unevenly distributed, a situation similar to that seen earlier in the Anaerolineae morphotype 0092 to which it is more closely related phylogenetically than it is to the Caldilinea morphotype 0803. FISH-based surveys showed that this 0803 phylotype is uncommon in Australian activated sludge systems, and where seen is present usually at low abundances. The FISH probes described here will facilitate attempts to map the distribution and impact of this Australian filament morphotype 0803 in activated sludge systems of different configurations in plants around the world.

  10. Protists as bioindicators in activated sludge: Identification, ecology and future needs. (United States)

    Foissner, Wilhelm


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

  11. Micropollutant degradation via extracted native enzymes from activated sludge. (United States)

    Krah, Daniel; Ghattas, Ann-Kathrin; Wick, Arne; Bröder, Kathrin; Ternes, Thomas A


    A procedure was developed to assess the biodegradation of micropollutants in cell-free lysates produced from activated sludge of a municipal wastewater treatment plant (WWTP). This proof-of-principle provides the basis for further investigations of micropollutant biodegradation via native enzymes in a solution of reduced complexity, facilitating downstream protein analysis. Differently produced lysates, containing a variety of native enzymes, showed significant enzymatic activities of acid phosphatase, β-galactosidase and β-glucuronidase in conventional colorimetric enzyme assays, whereas heat-deactivated controls did not. To determine the enzymatic activity towards micropollutants, 20 compounds were spiked to the cell-free lysates under aerobic conditions and were monitored via LC-ESI-MS/MS. The micropollutants were selected to span a wide range of different biodegradabilities in conventional activated sludge treatment via distinct primary degradation reactions. Of the 20 spiked micropollutants, 18 could be degraded by intact sludge under assay conditions, while six showed reproducible degradation in the lysates compared to the heat-deactivated negative controls: acetaminophen, N-acetyl-sulfamethoxazole (acetyl-SMX), atenolol, bezafibrate, erythromycin and 10,11-dihydro-10-hydroxycarbamazepine (10-OH-CBZ). The primary biotransformation of the first four compounds can be attributed to amide hydrolysis. However, the observed biotransformations in the lysates were differently influenced by experimental parameters such as sludge pre-treatment and the addition of ammonium sulfate or peptidase inhibitors, suggesting that different hydrolase enzymes were involved in the primary degradation, among them possibly peptidases. Furthermore, the transformation of 10-OH-CBZ to 9-CA-ADIN was caused by a biologically-mediated oxidation, which indicates that in addition to hydrolases further enzyme classes (probably oxidoreductases) are present in the native lysates. Although the

  12. Ammonium Ion Adsorption and Settleability Improvement Achieved in a Synthetic Zeolite-Amended Activated Sludge

    Institute of Scientific and Technical Information of China (English)

    Emilia Otal; Luís F. Vilches; Yolanda Luna; Rodrigo Poblete; Juan M. García-Maya; Constantino Fernández-Pereira


    Municipal wastewater treatment plants typically exhibit two classic problems:high ammonium concen-tration in water after conventional biological treatment and, in some cases, poor activated sludge sediment ability. Potential solutions to these problems were investigated by adding a synthetic zeolite obtained from coal fly ash to different steps of activated sludge treatment. The experimental results for ammonium removal fit well with the theo-retical adsorption isotherms of the Freundlich model with a maximum adsorption capacity of 13.72 mg·g−1. Utiliza-tion of this kind of zeolite to improve activated sludge sediment ability is studied for the first time in this work. It is found that the addition of the zeolite (1 g·L−1) to an activated sludge with settling problems significantly enhances its sediment ability and compact ability. This is confirmed by the sludge volume index (SVI), which was reduced from 163 ml·g−1 to 70 ml·g−1, the V60 value, which was reduced from 894 ml·L−1 to 427 ml·L−1, and the zeta poten-tial (ζ), which was reduced from−19.81 mV to−14.29 mV. The results indicate that the addition of this synthetic zeolite to activated sludge, as an additional waste management practice, has a positive impact on both ammonium removal and sludge settleability.

  13. Experimental plant for sludge composting. Plant experimental de compostaje de lodos

    Energy Technology Data Exchange (ETDEWEB)

    Cadenas, A.; Caellas, N.; Amengual, A.; Calafact, J.


    Results and expertise collected during the first year of exploitation of a compost experimental plant located in Mallorca (Spain): The plant is treating sludge from the biological treatment plant of water at the town of Felanitx and the compost produced is used in agriculture. (Author)

  14. Immobilization of activated sludge using improved polyvinyl alcohol (PVA) gel

    Institute of Scientific and Technical Information of China (English)


    The microbial immobilization method using polyvinyl alcohol (PVA) gel as an immobilizing material was improved and used for entrapment of activated sludge. The OUR (oxygen uptake rate) was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads was prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media (containing 250 mg/L COD and 25 mg/L NH4+-N). The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.

  15. Aerobic biotransformation of 14C-labeled 8-2 telomer B alcohol by activated sludge from a domestic sewage treatment plant. (United States)

    Wang, Ning; Szostek, Bogdan; Folsom, Patrick W; Sulecki, Lisa M; Capka, Vladimir; Buck, Robert C; Berti, William R; Gannon, John T


    This study investigated the biodegradation potential of 3-(14)C,1H,1H,2H,2H-perfluorodecanol [CF3(CF2)6(14)CF2CH2CH2OH, 14C-labeled 8-2 telomer B alcohol or 14C-labeled 8-2 TBA] by diluted activated sludge from a domestic wastewater treatment plant under aerobic conditions. After sample extraction with acetonitrile, biotransformation products were separated and quantified by LC/ARC (on-line liquid chromatography/accurate radioisotope counting) with a limit of quantification about 0.5% of the 14C counts applied to the test systems. Identification of biotransformation products was performed by quadrupole time-of-flight mass spectrometry. Three transformation products have been identified: CF3(CF2)6(14)CF2CH2COOH (8-2 saturated acid); CF3(CF2)6(14)CF=CHCOOH (8-2 unsaturated acid); and CF3(CF2)6(14)COOH (perfluorooctanoic acid, PFOA), representing 27, 6.0, and 2.1% of the initial 14C mass (14C counts applied) after 28 days, respectively. A transformation product, not yet reported in the literature, has also been observed and tentatively identified as CF3(CF2)6(14)CH2CH2COOH (2H,2H,3H,3H-perfluorodecanoic acid); it accounted for 2.3% of the mass balance after 28 days. The 2H,2H,3H,3H-perfluorodecanoic acid is likely a substrate for beta-oxidation, which represents one of the possible pathways for 8-2 telomer B alcohol degradation. The 8-2 saturated acid and 8-2 unsaturated acid cannot be directly used as substrates for beta-oxidation due to the proton deficiency in their beta-carbon (C3 carbon) and their further catabolism may be catalyzed by some other still unknown mechanisms. The 2H,2H,3H,3H-perfluorodecanoic acid may originate either from the major transformation product CF3(CF2)6(14)CF2CH2COOH or from other unidentified transformation products via multiple steps. Approximately 57% of the starting material remained unchanged after 28 days, likely due to its strong adsorption to the PTFE (poly(tetrafluoroethylene)) septa of the test vessels. No CF3(CF2)6(14)CF2COOH

  16. Application of forward osmosis (FO) under ultrasonication on sludge thickening of waste activated sludge. (United States)

    Nguyen, Nguyen Cong; Nguyen, Hau Thi; Chen, Shiao-Shing; Nguyen, Nhat Thien; Li, Chi-Wang


    Forward osmosis (FO) is an emerging process for dewatering solid-liquid stream which has the potential to be innovative and sustainable. However, the applications have still been hindered by low water flux and membrane fouling when activated sludge is used as the feed solution due to bound water from microbial cells. Hence, a novel strategy was designed to increase sludge thickening and reduce membrane fouling in the FO process under ultrasonic condition. The results from the ultrasound/FO hybrid system showed that the sludge concentration reached up to 20,400 and 28,400 mg/L from initial sludge concentrations of 3000 and 8000 mg/L with frequency of 40 kHz after 22 hours, while the system without ultrasound had to spend 26 hours to achieve the same sludge concentration. This identifies that the presence of ultrasound strongly affected sludge structure as well as sludge thickening of the FO process. Furthermore, the ultrasound/FO hybrid system could achieve NH4+-N removal efficiency of 96%, PO4(3-)-P of 98% and dissolved organic carbon (DOC) of 99%. The overall performance demonstrates that the proposed ultrasound/FO system using seawater as a draw solution is promising for sludge thickening application.

  17. Preparation of the sludge activated carbon with domestic sludge mixed agricultural straw (United States)

    Wang, Laifu; Wang, Yan; Lian, Jingyan


    Urban sewage sludge with complicated composition produce largely each year, pollution problem and resource utilization has increasingly become the focus of attention. Sewage sludge is utilized to prepare adsorbent that is a new type method. Agricultural stalks was added to material (urban sewage sludge) and activator (ZnCl2), calcined under the condition of no inert gas, and obtained domestic sludge activated carbon. The properties were measured by iodine adsorption value and BET, discussed influence factors of sludge activated carbon preparation, including activator concentration, solid-liquid ratio, calcific temperature and calcific time. The best process condition of orthogonal experiment had explored that activated time is 10 minutes, calcific temperature is 350°C, the activator concentration ZnCl2 is 3 mol/L and the mixing ratio of raw materials and activator is approximately 1:5. The iodine adsorption value and the optimal BET of as-obtained domestic sludge activated carbon is 445.06 mg/g, 525.31m2/g, respectively.

  18. Metal uptake by plants from sludge-amended soils: caution is required in the plateau interpretation

    DEFF Research Database (Denmark)

    Hamon, R.E.; Holm, Peter Engelund; Lorenz, S.E.;


    by increased sorption sites provided by the sludge constituents at the high sludge loading rates. We grew Raphanus sativus L. in a soil historically amended with sewage sludge at different rates and examined concentrations of Cd and Zn in the plants and in corresponding rhizosphere soil solution. Metal...

  19. Challenges encountered when expanding activated sludge models: a case study based on N2O production

    DEFF Research Database (Denmark)

    Snip, Laura; Boiocchi, Riccardo; Flores Alsina, Xavier;


    It is common practice in wastewater engineering to extend standard activated sludge models (ASMs) with extra process equations derived from batch experiments. However, such experiments have often been performed under conditions different from the ones normally found in wastewater treatment plants......-scale activated sludge plant. Finally, the simulation results show large differences in oxygen uptake rates, nitritation rates and consequently the quantity of N2O emission (G(N2O)) using the different models......It is common practice in wastewater engineering to extend standard activated sludge models (ASMs) with extra process equations derived from batch experiments. However, such experiments have often been performed under conditions different from the ones normally found in wastewater treatment plants...

  20. Influence of copper nanoparticles on the physical-chemical properties of activated sludge. (United States)

    Chen, Hong; Zheng, Xiong; Chen, Yinguang; Li, Mu; Liu, Kun; Li, Xiang


    The physical-chemical properties of activated sludge, such as flocculating ability, hydrophobicity, surface charge, settleability, dewaterability and bacteria extracellular polymer substances (EPS), play vital roles in the normal operation of wastewater treatment plants (WWTPs). The nanoparticles released from commercial products will enter WWTPs and can induce potential adverse effects on activated sludge. This paper focused on the effects of copper nanoparticles (CuNPs) on these specific physical-chemical properties of activated sludge. It was found that most of these properties were unaffected by the exposure to lower CuNPs concentration (5 ppm), but different observation were made at higher CuNPs concentrations (30 and 50 ppm). At the higher CuNPs concentrations, the sludge surface charge increased and the hydrophobicity decreased, which were attributed to more Cu2+ ions released from the CuNPs. The carbohydrate content of EPS was enhanced to defense the toxicity of CuNPs. The flocculating ability was found to be deteriorated due to the increased cell surface charge, the decreased hydrophobicity, and the damaged cell membrane. The worsened flocculating ability made the sludge flocs more dispersed, which further increased the toxicity of the CuNPs by increasing the availability of the CuNPs to the bacteria present in the sludge. Further investigation indicated that the phosphorus removal efficiency decreased at higher CuNPs concentrations, which was consistent with the deteriorated physical-chemical properties of activated sludge. It seems that the physical-chemical properties can be used as an indicator for determining CuNPs toxicity to the bacteria in activated sludge. This work is important because bacteria toxicity effects to the activated sludge caused by nanoparticles may lead to the deteriorated treatment efficiency of wastewater treatment, and it is therefore necessary to find an easy way to indicate this toxicity.

  1. 城市污水厂活性污泥强化自养反硝化菌研究%Experimental Study of Autotrophic Denitrification Bacteria Through Bioaugmentation of Activated Sludge from Municipal Wastewater Plant

    Institute of Scientific and Technical Information of China (English)

    常玉梅; 杨琦; 郝春博; 尚海涛; 姜体胜


    Activated sludge of municipal wastewater treatment plant was domesticated by sulfur as the electron donor under autotrophic.The sludge activity was determined by measuring growth rate of sludge. The removal efficiency of nitrate and sulfate production efficiency were analyzed by continuously measuring the concentration of NO3- -N and S024-. When the removal efficiency of nitrate was more than 90%, 16S rRNA genetic libraries were built up to compare their microbial biodiversity. The growth rate of sludge is 0.177 g/( L· d). The relation between concentration of nitrate and time meets first order reaction kinetics. The bacteria in the sludge affiliated with Beta-Proteobacteria, Deta-Proteobacteria, Gamma-Proteobacteria and Unclassified bacteria. Beta-Proteobacteria is the main phylum in the sludge. Bacteria related to Thiobacillus denitrificans from denitrifying bioreaetor perform 48.65%. In addition, the bacteria of Denitratisoma sp. , Curvibacter sp. , Thermomonas sp. Geobacter sp. are existed in the sludge. The study of autotrophic denitrifying bacteria diversity is conducive to optimization of reaction conditions and efficient removal of nitrate.%采集北京高碑店城市污水厂的反硝化污泥样品,以硫磺作为电子供体进行驯化培养.测定污泥的增长率来确定污泥活性,分别测定NO-N、SO浓度来确定硝酸盐的去除效率和硫酸盐生成速率.当硝酸盐去除率达到90%以上时,提取污泥中微生物总DNA,构建16S rRNA基因片段克隆文库来分析细菌群落结构,结果表明,污泥的增长率为0.177 g/(L·d),污泥中硝酸盐浓度与时间的关系符合一级反应.污泥中细菌类群主要为Beta-Proteobacteria、Deta-Proteobacteria、Gamma-Proteobacteria和Unclassified bacteria,其中Beta-Proteobacteria类细菌占主导地位.在成熟的反硝化污泥中,自养反硝化菌Thiobacillusdenitrificans占所占比例高达48.65%.此外,反应器中还存在Denitratisoma sp.、Curvibacter sp

  2. Study on factors of affecting sedimentation performance of activated sludge in A-step of AB process

    Institute of Scientific and Technical Information of China (English)

    ZHOUJian; TIANWenlong; LONGTengrui


    The factors including inflow SS, pythogenous sewage, loading rate Ns, dissolved oxygen which affect sedimentation performance of A-step activated sludge were studied in the paper. The experimental results indicated: the inflow SS distinctly improve sedimentation performance of activated sludge; the pythogenous sewage easily worsen sedimentation performance of activated sludge, and canceling primary sedimentation tank and cesspool would avail to stable running of sewage treatment plant. The effect of loading rate Ns on EPS is highly remarkable, and EPS and polysaccharide are correlated evidently with sedimentation performance of activated sludge. When high loading rate Ns is 3.0 kgBOD5/kgMLSS·d, EPS is 17.15mgEPS/gVSS and polysaccharide is 8.15mg/g VSS, which is less 40% than activated sludge of 0.3 kgBOD5/kgMLSS·d loading rate Ns; meanwhile the effect of dissolved oxygen on EPS is less, and dissolved oxygen does not affect sedimentation performance of activated sludge in high loading rate; the polysaccharide content of activated sludge in high loading rate does not benefit the growth of filament, and furthermore the hydrophobicity of activated sludge is good, which cause good sedimentation performance of sludge in high loading rate.

  3. Occurrence of bisphenol A in wastewater and wastewater sludge of CUQ treatment plant

    Directory of Open Access Journals (Sweden)

    Dipti Prakash Mohapatra


    Full Text Available The identification and quantification of bisphenol A (BPA in wastewater (WW and wastewater sludge (WWS is of major interest to assess the endocrine activity of treated effluent discharged into the environment. BPA is manufactured in high quantities fro its use in adhesives, powder paints, thermal paper and paper coatings among others. Due to the daily use of these products, high concentration of BPA was observed in WW and WWS. BPA was measured in samples from Urban Community of Quebec wastewater treatment plant located in Quebec (Canada using LC-MS/MS method. The results showed that BPA was present in significant quantities (0.07 μg L–1 to 1.68 μg L–1 in wastewater and 0.104 μg g–1 to 0.312 μg g–1 in wastewater sludge in the wastewater treatment plant (WWTP. The treatment plant is efficient (76 % in removal of pollutant from process stream, however, environmentally significant concentrations of 0.41 μg L–1 were still present in the treated effluent. Rheological study established the partitioning of BPA within the treatment plant. This serves as the base to judge the portion of the process stream requiring more treatment for degradation of BPA and also in selection of different treatment methods. Higher BPA concentration was observed in primary and secondary sludge solids (0.36 and 0.24 μg g–1, respectively as compared to their liquid counterpart (0.27 and 0.15 μg L–1, respectively separated by centrifugation. Thus, BPA was present in significant concentrations in the WWTP and mostly partitioned in the solid fraction of sludge (Partition coefficient (Kd for primary, secondary and mixed sludge was 0.013, 0.015 and 0.012, respectively.


    Directory of Open Access Journals (Sweden)

    Agnieszka Tomska


    The aim of this work was to evaluate the effect of selected antibiotics - sulfanilamide and erythromycin on activated sludge dehydrogenase activity with use of trifenyltetrazolinum chloride (TTC test. Dehydrogenases activity is an indicator of biochemical activity of microorganisms present in activated sludge or the ability to degrade organic compounds in waste water. TTC test is particularly useful for the regularity of the course of treatment, in which the presence of inhibitors of biochemical reactions and toxic compounds are present. It was observed that the dehydrogenase activity decreases with the increase of a antibiotics concentration. The lowest value of the dehydrogenase activity equal to 32.4 μmol TF / gMLSS obtained at sulfanilamide concentration 150mg / l. For this sample, an inhibition of dehydrogenase activity was 31%.

  5. Using Boiling for Treating Waste Activated Sludge

    Institute of Scientific and Technical Information of China (English)


    In this work we investigated the feasibility of using short time, low superheat boiling to treat biological sludge. The treated sludge exhibited reduced filterability and enhanced settleability. The boiling treatment released a large amount of extra-cellular polymers (ECPs) from the solid phase and reduced the microbial density levels of the total coliform bacteria and the heterotrophic bacteria. A diluted sludge is preferable for its high degree of organic hydrolysis and sufficient reduction in microbial density levels.

  6. Effect of Salinity Variations on the Performance of Activated Sludge System

    Institute of Scientific and Technical Information of China (English)



    Objective To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. Methods The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC), oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically. Results The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/L and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading. Conclusion The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.

  7. Can aquatic worms enhance methane production from waste activated sludge? (United States)

    Serrano, Antonio; Hendrickx, Tim L G; Elissen, Hellen H J; Laarhoven, Bob; Buisman, Cees J N; Temmink, Hardy


    Although literature suggests that aquatic worms can help to enhance the methane production from excess activated sludge, clear evidence for this is missing. Therefore, anaerobic digestion tests were performed at 20 and at 30°C with sludge from a high-loaded membrane bioreactor, the aquatic worm Lumbriculus variegatus, feces from these worms and with mixtures of these substrates. A significant synergistic effect of the worms or their feces on methane production from the high-loaded sludge or on its digestion rate was not observed. However, a positive effect on low-loaded activated sludge, which generally has a lower anaerobic biodegradability, cannot be excluded. The results furthermore showed that the high-loaded sludge provides an excellent feed for L. variegatus, which is promising for concepts where worm biomass is considered a resource for technical grade products such as coatings and glues.

  8. Denitrification, activity of bacterial flocs, and growth of a filamentous bacterium in relation with the bulking of activated sludge

    NARCIS (Netherlands)

    Krul, J.M.


    Activated sludge with poor settling characteristics is caught under the term "bulking" sludge. Various types of bulking activated sludge can be distinguished.1) Sludge containing an abundance of filamentous microorganisms.2) Sludge, characterized by excessive amount of bacterial slime.3) Flotating s

  9. Co-digestion of municipal sludge and external organic wastes for enhanced biogas production under realistic plant constraints. (United States)

    Tandukar, Madan; Pavlostathis, Spyros G


    A bench-scale investigation was conducted to select external organic wastes and mixing ratios for co-digestion with municipal sludge at the F. Wayne Hill Water Resources Center (FWHWRC), Gwinnett County, GA, USA to support a combined heat and power (CHP) project. External wastes were chosen and used subject to two constraints: a) digester retention time no lower than 15 d; and b) total biogas (methane) production not to exceed a specific target level based on air permit constraints on CO2 emissions. Primary sludge (PS), thickened waste activated sludge (TWAS) and digested sludge collected at the FWHWRC, industrial liquid waste obtained from a chewing gum manufacturing plant (GW) and dewatered fat-oil-grease (FOG) were used. All sludge and waste samples were characterized and their ultimate digestibility was assessed at 35 °C. The ultimate COD to methane conversion of PS, TWAS, municipal sludge (PS + TWAS; 40:60 w/w TS basis), GW and FOG was 49.2, 35.2, 40.3, 72.7, and 81.1%, respectively. Co-digestion of municipal sludge with GW, FOG or both, was evaluated using four bench-scale, mesophilic (35 °C) digesters. Biogas production increased significantly and additional degradation of the municipal sludge between 1.1 and 30.7% was observed. Biogas and methane production was very close to the target levels necessary to close the energy deficit at the FWHWRC. Co-digestion resulted in an effluent quality similar to that of the control digester fed only with the municipal sludge, indicating that co-digestion had no adverse effects. Study results prove that high methane production is achievable with the addition of concentrated external organic wastes to municipal digesters, at acceptable higher digester organic loadings and lower retention times, allowing the effective implementation of CHP programs at municipal wastewater treatment plants, with significant cost savings.

  10. Waste Sludge Characteristics of a Wastewater Treatment Plant Compared with Environmental Standards

    Directory of Open Access Journals (Sweden)

    AR Mesdaghinia


    Full Text Available Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefits for plants and soils. Thereupon, land application of sludge has received much attention over the traditional incineration and dump in sea. The comprehensive regulations of U.S.EPA title 40 CFR parts 503 include criteria and standards for land application of sludge. One of the most important wastewater treatment plants in Tehran, Iran is Shoosh Plant, which applies its waste sludge in agricultural lands after dewatering in drying beds. In this research, waste sludge from drying beds was examined according to 40 CFR parts 503. Results indicate that the dehydrated sludge has not the characteristics required for final discharge. If the dewatering process in the existing beds of the plant would be modified according to title 40 CFR part 503, the standard of Pathogen Reduction class B would be achieved. Waste sludge of drying bed must be applied in agricultural land with respect to the conditions of application method that is presented in vector attraction reduction. Concentration of this waste sludge is less than ceiling concentration limits identified by title 40 CFR parts 503.

  11. Activated sludge model No. 2d, ASM2d

    DEFF Research Database (Denmark)

    Henze, M.


    The Activated Sludge Model No. 2d (ASM2d) presents a model for biological phosphorus removal with simultaneous nitrification-denitrification in activated sludge systems. ASM2d is based on ASM2 and is expanded to include the denitrifying activity of the phosphorus accumulating organisms (PAOs......). This extension of ASM2 allows for improved modeling of the processes, especially with respect to the dynamics of nitrate and phosphate. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved....

  12. Selective hydrolysis of wastewater sludge. Part 1. Model calculations and cost benefit analysis for Esbjerg West waste water treatment plant, Denmark

    Energy Technology Data Exchange (ETDEWEB)

    OEstergaard, N. (Eurotec West A/S (DK)); Thomsen, Anne Belinda; Thygesen, Anders; Bangsoe Nielsen, H. (Risoe National Laboratory, DTU (DK)); Rasmussen, Soeren (SamRas (DK))


    The project 'Selective hydrolysis of wastewater sludge' investigates the possibilities of utilizing selective hydrolysis of sludge at waste water treatment plants to increase the production of biogas based power and heat, and at the same time reduce power consumption for handling and treatment of nitrogen and sludge as well as for disposal of the sludge. The selective hydrolysis system is based on the fact that an anaerobic digestion before a hydrolysis treatment increases the hydrolysis efficiency, as the production of volatile organic components, which might inhibit the hydrolysis efficiency, are not produced to the same extent as may be the case for a hydrolysis made on un-digested material. Furthermore it is possible to separate ammonia from the sludge without using chemicals; it has, however, proven difficult to treat wastewater sludge, as the sludge seems to be difficult to treat in the laboratory using simple equipment. Esbjerg Wastewater Treatment Plant West, Denmark, is used as model plant for the calculations of the benefits using selective hydrolysis of sludge as if established at the existing sludge digester system. The plant is a traditional build plant based on the activated sludge concept in addition to traditional digester technology. The plant treats combined household and factory wastewater with a considerable amount of the wastewater received from the industries. During the project period Esbjerg Treatment Plant West went through considerable process changes, thus the results presented in this report are based on historical plant characteristics and may be viewed as conservative relative to what actually may be obtainable. (BA)

  13. Scum sludge as a potential feedstock for biodiesel production from wastewater treatment plants. (United States)

    Wang, Yi; Feng, Sha; Bai, Xiaojuan; Zhao, Jingchan; Xia, Siqing


    The main goal of this study was to compare the component and yield of biodiesel obtained by different methods from different sludge in a wastewater treatment plant. Biodiesel was produced by ex-situ and in-situ transesterification of scum, primary and secondary sludge respectively. Results showed that scum sludge had a higher calorific value and neutral lipid than that of primary and secondary sludge. The lipid yield accounted for one-third of the dried scum sludge and the maximum yield attained 22.7% under in-situ transesterification. Furthermore the gas chromatography analysis of fatty acid methyl esters (FAMEs) revealed that all sludge contained a significant amount of palmitic acid (C16:0) and oleic acid (C18:1) regardless of extraction solvents and sludge types used. However, the difference lay in that oleic acid methyl ester was the dominant component in FAMEs produced from scum sludge while palmitic acid methyl ester was the dominant component in FAMEs from primary and secondary sludge. In addition, the percentage of unsaturated fatty acid ester in FAMEs from scum sludge accounted for 57.5-64.1% of the total esters, which was higher than the equivalent derived from primary and secondary sludge. In brief, scum sludge is a potential feedstock for the production of biodiesel and more work is needed in the future.

  14. Extraction DNA from Activated Sludge-Comparing with Soil Sample

    Institute of Scientific and Technical Information of China (English)

    谢冰; 奚旦立; 陈季华


    DNA directly extraction from activated sludge and soil sample with enzyme lyses methods was investigated in this paper. DNA yield from activated sludge was 3.0 mg/g. VLSS, and 28.2-43.8 μg/g soil respectively. The resulting DNA is suitable for PCR.By studied methods, higher quality and quantity of sludge DNA could be obtained rapidly and inexpensively from large number of samples, and the PCR product obtained from this protocol was not affected by contaminated higher concentration of heavy metals.

  15. On-line Measurements of Settling Charateristics in Activated Sludge

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Larsen, Torben


    An on-line settling column for measuring the dynamic variations of settling velocity of activated sludge has been developed. The settling column is automatic and self-cleansing insuring continuous and reliable measurements. The settling column was tested on sludge from a batch reactor where sucrose...... was added as an impulse to activated sludge. The continuous measurement of settling velocity revealed a highly dynamic response after the sucrose was added. The result were verified with simultaneous measurement of the initial settling rate. A 200 hour experiment showed variations in settling velocity...

  16. A new method study biodegradation kinetics of anorganic trace pollutants by activated sludge

    NARCIS (Netherlands)

    Temmink, H.; Klapwijk, A.


    A reliable prediction of the behaviour of organic trace compounds in activated sludge plants requires an accurate input of the biodegradation kinetics. Often these kinetics are extrapolated from the results of standardised biodegradation tests. However, these tests generally are not designed to yiel

  17. Short Horizon Control Strategies for an Alternating Activated Sludge Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard


    Three control strategies allowing improved operational flexibility of an alternating type activated sludge process are presented in a unified model based framework. The control handles employed are the addition rate of an external carbon source to denitrification, the cycle length...

  18. Characterization of Wastewater for Modelling of Activated Sludge Processes

    DEFF Research Database (Denmark)

    Henze, Mogens


    The fractionation of organic matter in the various parts which are used for mathematical modelling is discussed. The fractions include inert soluble, readily biodegradable, rapidly hydrolyzable, slowly hydrolyzable, biomass and inert suspended material. Methods for measuring are also discussed. F...... in a specific wastewater seem to be constant even when concentrations vary. Wastewater input to sewers and the sewer transport system significantly influences the raw wastewater composition at treatment plants........ Fractionation of biomass in wastewater and in activated sludge is difficult at present, as methods are only partly developed. Nitrogen fractions in wastewater are mainly inorganic. The organic nitrogen fractions are coupled to the organic COD fractions. The fractions of COD, biomass and nitrogen found...

  19. Application of Gamma irradiation in treatment of Waste Activated Sludge to Obtain Class a Biosolids

    Directory of Open Access Journals (Sweden)

    Mohammed I. AL-Ghonaiem


    Full Text Available Problem statement: The main objective of the current study was investigation of the possible application of Gamma irradiation for treatment of the activated sludge generated wastewater treatment stations, to achieve the standard requirements in term of pathogens content. Approach: Activated sludge samples were collected from Riyadh wastewater plant and analyzed quantitatively for the presence of important bacterial parameters including fecal coliforms and Salmonella spp. The collected samples were treated with various doses of Gamma irradiation and bacterial count was determined. Results: The results indicated that all tested sludge samples were positive for the presence of fecal coliforms and Salmonella spp, with different counts in different stages of wastewater treatment. The raw sludge showed to have the highest coliforms and Salmonella spp counts of 1.1×108 and 2×103 MPN g-1 dry sludge, respectively. Furthermore, coliforms and Salmonella spp were detected in final resulted sludge with count of 2.5×107 and 6×102 MPN g-1 dry sludge, respectively. It was found that treatment of samples with gamma irradiation was able to reduce the fecal coliforms and Salmonella spp effectively and the reduction efficiency was increased by increasing the irradiation dose. Fecal coliforms and Salmonella counts were reduced to less than 100 MPN g-1 dry sludge by exposing to 1.5 and 0.25 kGy respectively. Furthermore, Gamma radiation dose of 2.0 kGy was able to remove both fecal coliforms and Salomnella spp completely. In addition, D10 values were determined and was found to be 0.25 and 0.24 kGy for fecal coliforms and Salmonella spp., respectively. Conclusion/Recommendations: The results indicating that the resulted activated sludge generated from Riyadh wastewater plant are rich with important pathogens and therefore further treatment procedures are necessary to achieve the required standards, before any land application. Application of

  20. Reasonable management plan of sludge in sewage disposal plant

    Energy Technology Data Exchange (ETDEWEB)

    Yum, Kyu Jin; Koo, Hyun Jung [Korea Environment Institute, Seoul (Korea)


    The compost method, which is widely used as a sewage disposal recycling in Korea, is now basically impossible to recycle sludge to compost by the Ministry of Agriculture and Forestry announcement. Therefore, the disposal of sludge will be much harder with reducing the amount of sludge used as compost. The amount of sludge other than using as compost is very small, so the development of various sludge recycling and use will be needed with regulations. This study was implemented to help the establishment of sewage sludge recycling policy in Korea. 30 refs., 17 figs., 58 tabs.

  1. Concentration of heavy metals in sweet passion fruit plants in two soils treated with sewage sludge

    Directory of Open Access Journals (Sweden)

    Leonardo Nazário da Silva Santos


    Full Text Available The aim of this work was to evaluate the levels of heavy metals in plants of sweet fruit in two different soil types treated with sewage sludge. The experiment was performed in randomized block design with six replication of 25 seeds and treatments in a 3 x 2 factorial distribution with the factors being three sewage sludge level (without sewage sludge, with sewage sludge (5 t ha-1, with sewage sludge corrected to 60% saturation of bases (5 t ha-1, two different soil types (Red-Yellow Latosol and Red Argisol. At 28 days was evaluated the germination and 60 days after emergence were determined the concentrations of Zinc, Chromium and Copper. The results indicated that application of sewage sludge in soils provided no toxicity or contamination of plants by the metals.Key-words: Passiflora alata Dryander, biossolids, phytotoxicity.

  2. Chronic Response of Waste Activated Sludge Fermentation to Titanium Dioxide Nanoparticles☆

    Institute of Scientific and Technical Information of China (English)

    Yinguang Chen; Hui Mu; Xiong Zheng⁎


    Due to the large-scale production and wide applications, many nanoparticles (NPs) enter wastewater treatment plants and accumulate in activated sludge. It is reported that titanium dioxide (TiO2) NPs show severe damage to many model microbes. However, it is stil unknown whether the long-term (e.g., 100 d) presence of TiO2 NPs would affect the performance of sludge fermentation. In this study, long-term exposure experiments (105 d) were conducted to investigate the potential risk of TiO2 NPs to sludge fermentation system. It is found that the presence of environmental y relevant [6 mg·(g TSS)−1] and higher [150 mg·(g TSS)−1] concentrations of TiO2 NPs does not affect methane production from sludge fermentation. The analysis of fluorescence in situ hybridiza-tion indicates that these concentrations of TiO2 NPs present marginal influences on abundances of bacteria and methanogenic archaea in sludge fermentation system. The viability of sludge microorganisms and activities of key enzymes related to methane production such as protease, acetate kinase, and coenzyme F420 are unchanged by the long-term presence of 6 and 150 mg·(g TSS)−1 of TiO2 NPs. Further investigations reveal that the insolu-bility of NPs and the protection role of sludge extracellular polymeric substances are the main reasons for the marginal influence of TiO2 NPs on sludge fermentation.

  3. Effects of sewage sludge on Di-(2-ethylhexyl) phthalate uptake by plants. [Lactuca sativa L. ; Daucus carota L. ; Capsicum annuum L. ; Festuca arundinacea Schreb

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, J.M.; O' Connor, G.A.; Eiceman, G.A. (New Mexico State Univ., Las Cruces (USA))

    Di-(2-ethylhexyl) phthalate (DEHP) is a priority organic pollutant frequently found in municipal sludges. A greenhouse study was conducted to determine the effect of sludge on plant uptake of {sup 14}C-DEHP (carbonyl labeled). Plants grown included three food chain crops, lettuce (Lactuca sativa L.), carrot (Daucus carota L.) and chile pepper (Capsicum annuum L.) and tall fescue (Festuca arundinacea Schreb.). Net {sup 14}C concentration in plants grown in soil amended with {sup 14}C-DEHP-contaminated sludge was independent of sludge rate (at the same DEHP loading) for lettuce, chile fruit, and carrot roots. Net {sup 14}C concentration, however, was inversely related to sludge rate in carrot tops, fescue, and chile plants. Intact DEHP was not detected in plants by gas chromatography/mass spectrometry analysis. Calculated plant DEHP concentrations (based on measured net {sup 14}C concentrations and DEHP specific activities) were generally correlated better with DEHP soil solution concentrations than with total DEHP soil concentrations. Net {sup 14}C-DEHP bioconcentration factors were calculated from initial soil DEHP concentration and plant fresh weights. Bioconcentration factors ranged from 0.01 to 0.03 for fescue, lettuce, carrots, and chile, suggesting little DEHP uptake. Additionally, because intact DEHP was not detected in any plants, DEHP uptake by plants was of minor importance and would not limit sludge additions to soils used to grow these crops.

  4. Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic conditions

    DEFF Research Database (Denmark)

    Chen, Xijuan; Nielsen, Jeppe Lund; Furgal, Karolina;


    Triclosan is an antimicrobial agent which is widely used in household and personal care products. Widespread use of this compound has led to the elevated concentrations of triclosan in wastewater, wastewater treatment plants (WWTPs) and receiving waters. Removal of triclosan and formation...... of triclosan- methyl was investigated in activated sludge from a standard activated sludge WWTP equipped with enhanced biological phosphorus removal. The removal was found to occur mainly under aerobic conditions while under anoxic (nitrate reducing) and anaerobic conditions rather low removal rates were...... determined. In a laboratory-scale activated sludge reactor 75% of the triclosan was removed under aerobic conditions within 150 h, while no removal was observed under anaerobic or anoxic conditions. One percent of the triclosan was converted to triclosan-methyl under aerobic conditions, less under anoxic...

  5. Characteristics of PAHs adsorption on inorganic particles and activated sludge in domestic wastewater treatment. (United States)

    Liu, J J; Wang, X C; Fan, B


    The occurrence of polycyclic aromatic hydrocarbons (PAHs) in a domestic wastewater treatment plant (WWTP) was investigated in a 1 year period. In order to understand how PAHs were removed at different stages of the treatment process, adsorption experiments were conducted using quartz sand, kaolinite, and natural clay as inorganic adsorbents and activated sludge as organic adsorbent for adsorbing naphthalene, phenanthrene, and pyrene. As a result, the adsorption of PAHs by the inorganic adsorbents well followed the Langmuir isotherm while that by the activated sludge well followed the Freundlich isotherm. By bridging equilibrium partitioning coefficient with the parameters of adsorption isotherm, a set of mathematical models were developed. Under an assumption that in the primary settler PAHs removal was by adsorption onto inorganic particles and in the biological treatment unit it was by adsorption onto activated sludge, the model calculation results fairly reflected the practical condition in the WWTP.

  6. Activity, life time and effect of hydrolytic enzymes for enhanced biogas production from sludge anaerobic digestion. (United States)

    Odnell, Anna; Recktenwald, Michael; Stensén, Katarina; Jonsson, Bengt-Harald; Karlsson, Martin


    As an alternative to energy intensive physical methods, enzymatic treatment of sludge produced at wastewater treatment plants for increased hydrolysis and biogas production was investigated. Several hydrolytic enzymes were assessed with a focus on how enzyme activity and life time was influenced by sludge environments. It could be concluded that the activity life time of added enzymes was limited (enzymes, due to endogenous protease activity. In biogas in situ experiments, subtilisin at a 1% mixture on basis of volatile solids, was the only enzyme providing a significantly increased biomethane production of 37%. However, even at this high concentration, subtilisin could not hydrolyze all available substrate within the life time of the enzyme. Thus, for large scale implementation, enzymes better suited to the sludge environments are needed.

  7. Effect of acetic acid on lipid accumulation by glucose-fed activated sludge cultures

    Energy Technology Data Exchange (ETDEWEB)

    Mondala, Andro; Hernandez, Rafael; French, Todd; McFarland, Linda; Sparks, Darrell; Holmes, William; Haque, Monica


    The effect of acetic acid, a lignocellulose hydrolysis by-product, on lipid accumulation by activated sludge cultures grown on glucose was investigated. This was done to assess the possible application of lignocellulose as low-cost and renewable fermentation substrates for biofuel feedstock production. Results: Biomass yield was reduced by around 54% at a 2 g L -1 acetic acid dosage but was increased by around 18% at 10 g L -1 acetic acid dosage relative to the control run. The final gravimetric lipid contents at 2 and 10 g L -1 acetic acid levels were 12.5 + 0.7% and 8.8 + 3.2% w/w, respectively, which were lower than the control (17.8 + 2.8% w/w). However, biodiesel yields from activated sludge grown with acetic acid (5.6 + 0.6% w/w for 2 g L -1 acetic acid and 4.2 + 3.0% w/w for 10 g L -1 acetic acid) were higher than in raw activated sludge (1-2% w/w). The fatty acid profiles of the accumulated lipids were similar with conventional plant oil biodiesel feedstocks. Conclusions: Acetic acid enhanced biomass production by activated sludge at high levels but reduced lipid production. Further studies are needed to enhance acetic acid utilization by activated sludge microorganisms for lipid biosynthesis.

  8. Ciliated protozoa community of a combined UASB-activated sludge system in southeastern Brazil. (United States)

    Siqueira-Castro, Isabel Cristina Vidal; Greinert-Goulart, Juliane Araújo; Rossetto, Renato; Guimarães, José Roberto; Franco, Regina Maura Bueno


    The aims of the present study were (1) to evaluate the abundance and taxonomic composition of ciliated protozoa in the activated sludge of a full-scale combined anaerobic-aerobic system operating in a tropical country and (2) to study the relationship between the effluent quality, the physicochemical variables, and the ciliates present in the operating system. The total ciliate fauna of the activated sludge of the Piçarrão Wastewater Treatment Plant (Piçarrão WWTP) was composed of 36 morphospecies belonging to 33 genera. These included 21 species observed in the activated sludge samples on the day of collection and 15 species found in cultures. The activated sludge of the Piçarrão WWTP contained a diversified ciliate community composed mainly of indicator organisms. The most frequently occurring morphospecies were Aspidisca cicada, Vorticella spp., Gastronauta aloisi, Acineria uncinata, and Epistylis plicatilis complex. These results showed that satisfactory operating conditions prevailed at the Piçarrão WWTP. In the combined UASB-activated sludge system, the presence of Aspidisca cicada suggests the occurrence of denitrification in the process while the presence of Acineria uncinata and G. alosi indicates the removal of carbonaceous organic matter.

  9. Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Suschka Jan


    Full Text Available Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

  10. Chitosan use in chemical conditioning for dewatering municipal-activated sludge. (United States)

    Zemmouri, H; Mameri, N; Lounici, H


    This work aims to evaluate the potential use of chitosan as an eco-friendly flocculant in chemical conditioning of municipal-activated sludge. Chitosan effectiveness was compared with synthetic cationic polyelectrolyte Sedipur CF802 (Sed CF802) and ferric chloride (FeCl₃). In this context, raw sludge samples from Beni-Messous wastewater treatment plant (WWTP) were tested. The classic jar test method was used to condition sludge samples. Capillary suction time (CST), specific resistance to filtration (SRF), cakes dry solid content and filtrate turbidity were analyzed to determine filterability, dewatering capacity of conditioned sludge and the optimum dose of each conditioner. Data exhibit that chitosan, FeCl₃and Sed CF802 improve sludge dewatering. Optimum dosages of chitosan, Sed CF802 and FeCl₃allowing CST values of 6, 5 and 9 s, were found, respectively, between 2-3, 1.5-3 and 6 kg/t ds. Both polymers have shown faster water removal with more permeable sludge. SRF values were 0.634 × 10¹², 0.932 × 10¹² and 2 × 10¹² m/kg for Sed CF802, chitosan and FeCl₃respectively. A reduction of 94.68 and 87.85% of the filtrate turbidity was obtained with optimal dosage of chitosan and Sed CF802, respectively. In contrast, 54.18% of turbidity abatement has been obtained using optimal dosage of FeCl₃.

  11. Effects of Heavy Metals on Activated Sludge Microorganism

    Institute of Scientific and Technical Information of China (English)

    XIE Bing; XI Dan-li; CHEN Ji-hua


    The efforts of heavy metals on activated sludge microorganisms are reviewed. Although some heavy metals play an important role in the life of microorganism, heavy metals concentrations above toxic levels inhibit biological processes. Copper, zinc, nickel,cadmium and chromium were mostly studied because of their toxicity and widely used, regardless of single or combination. The microorganism response to these heavy metals varied with species and concentrations of metals,factors such as pH, sludge age, MLSS etc. also affect toxicity on the microorganism. The acclimation could extend the microorganism tolerance of heavy metals. The effects of heavy metals on sludge microorganisms could be described with different models, such as Sigmoidal and Monod equation. The kinetic constants are the useful indexes to estimate the heavy metals inhibition on activated sludge system. Methods to measure the toxicity and effects on microorganism community were also reviewed.

  12. Production and characterization of granular activated carbon from activated sludge

    Directory of Open Access Journals (Sweden)

    Z. Al-Qodah


    Full Text Available In this study, activated sludge was used as a precursor to prepare activated carbon using sulfuric acid as a chemical activation agent. The effect of preparation conditions on the produced activated carbon characteristics as an adsorbent was investigated. The results indicate that the produced activated carbon has a highly porous structure and a specific surface area of 580 m²/g. The FT-IR analysis depicts the presence of a variety of functional groups which explain its improved adsorption behavior against pesticides. The XRD analysis reveals that the produced activated carbon has low content of inorganic constituents compared with the precursor. The adsorption isotherm data were fitted to three adsorption isotherm models and found to closely fit the BET model with R² equal 0.948 at pH 3, indicating a multilayer of pesticide adsorption. The maximum loading capacity of the produced activated carbon was 110 mg pesticides/g adsorbent and was obtained at this pH value. This maximum loading was found experimentally to steeply decrease as the solution pH increases. The obtained results show that activated sludge is a promising low cost precursor for the production of activated carbon.

  13. Comparison of microbial communities of activated sludge and membrane biofilm in 10 full-scale membrane bioreactors. (United States)

    Jo, Sung Jun; Kwon, Hyeokpil; Jeong, So-Yeon; Lee, Chung-Hak; Kim, Tae Gwan


    Operation of membrane bioreactors (MBRs) for wastewater treatment is hampered by the membrane biofouling resulting from microbial activities. However, the knowledge of the microbial ecology of both biofilm and activated sludge in MBRs has not been sufficient. In this study, we scrutinized microbial communities of biofilm and activated sludge from 10 full-scale MBR plants. Overall, Flavobacterium, Dechloromonas and Nitrospira were abundant in order of abundance in biofilm, whereas Dechloromonas, Flavobacterium and Haliscomenobacter in activated sludge. Community structure was analyzed in either biofilm or activated sludge. Among MBRs, as expected, not only diversity of microbial community but also its composition was different from one another (p  0.05). Effects of ten environmental factors on community change were investigated using Spearman correlation. MLSS, HRT, F/M ratio and SADm explained the variation of microbial composition in the biofilm, whereas only MLSS did in the activated sludge. Microbial networks were constructed with the 10 environmental factors. The network results revealed that there were different topological characteristics between the biofilm and activated sludge networks, in which each of the 4 factors had different associations with microbial nodes. These results indicated that the different microbial associations were responsible for the variation of community composition between the biofilm and activated sludge.

  14. Co-conditioning of the anaerobic digested sludge of a municipal wastewater treatment plant with alum sludge: benefit of phosphorus reduction in reject water. (United States)

    Yang, Y; Zhao, Y Q; Babatunde, A O; Kearney, P


    In this study, alum sludge was introduced to co-conditioning and dewatering with an anaerobic digested sludge from a municipal wastewater treatment plant, to examine the role of the alum sludge in improving the dewaterbility of the mixed sludge and also in immobilizing phosphorus in the reject water. Experiments have demonstrated that the optimal mix ratio for the two sludges is 2:1 (anaerobic digested sludge:alum sludge: volume basis), and this can bring approximately 99% phosphorus reduction in the reject water through the adsorption of phosphorus by alum in the sludge. The phosphorus loading in wastewater treatment plants is itself derived from the recycling of reject water during the wastewater treatment process. Consequently, this co-conditioning and dewatering strategy can achieve a significant reduction in phosphorus loading in wastewater treatment plants. In addition, the use of the alum sludge has been shown to beneficially enhance the dewaterability of the resultant mixed sludge, by decreasing both the specific resistance to filtration and the capillary suction time. This is attributed to the alum sludge acting in charge neutralization and/or as adsorbent for phosphate in the aqueous phase of the sludge. Experiments have also demonstrated that the optimal polymer (Superfloc C2260, Cytec, Botlek, Netherlands) dose for the anaerobic digested sludge was 120 mg/L, while the optimal dose for the mixed sludge (mix ratio 2:1) was 15 mg/L, highlighting a huge savings in polymer addition. Therefore, from the technical perspective, the co-conditioning and dewatering strategy can be viewed as a "win-win" situation. However, for its full-scale application, integrated cost-effective analysis of process capabilities, sludge transport, increased cake disposal, additional administration, polymer saving, and so on, should be factored in.

  15. Exploring the potential of applying proteomics for tracking bisphenol A and nonylphenol degradation in activated sludge. (United States)

    Collado, Neus; Buttiglieri, Gianluigi; Kolvenbach, Boris A; Comas, Joaquim; Corvini, Philippe F-X; Rodríguez-Roda, Ignasi


    A significant percentage of bisphenol A and nonylphenol removal in municipal wastewater treatment plants relies on biodegradation. Nonetheless, incomplete information is available concerning their degradation pathways performed by microbial communities in activated sludge systems. Hydroquinone dioxygenase (HQDO) is a specific degradation marker enzyme, involved in bisphenol A and nonylphenol biodegradation, and it can be produced by axenic cultures of the bacterium Sphingomonas sp. strain TTNP3. Proteomics, a technique based on the analysis of microbial community proteins, was applied to this strain. The bacterium proteome map was obtained and a HQDO subunit was successfully identified. Additionally, the reliability of the applied proteomics protocol was evaluated in activated sludge samples. Proteins belonging to Sphingomonas were searched at decreasing biomass ratios, i.e. serially diluting the bacterium in activated sludge. The protein patterns were compared and Sphingomonas proteins were discriminated against the ones from sludge itself on 2D-gels. The detection limit of the applied protocol was defined as 10(-3) g TTNP3 g(-1) total suspended solids (TSSs). The results proved that proteomics can be a promising methodology to assess the presence of specific enzymes in activated sludge samples, however improvements of its sensitivity are still needed.

  16. Biological anoxic phosphorus removal in a continuous-flow external nitrification activated sludge system

    Energy Technology Data Exchange (ETDEWEB)

    Kapagiannidis, A. G.; Aivasidis, A.


    Application of Biological Nutrient Removal (BNR) process in wastewater treatment is necessitated for the protection of water bodies from eutrophication. an alternative BNR method is tested for simultaneous Carbon (C), Nitrogen (N) and Phosphorus (P) removal in a continuous-flow bench scale plant for municipal wastewater treatment. The plant operation is based on the activity of two microbial populations which grow under different operational conditions (two sludge system). (Author)

  17. Cometabolic degradation of organic wastewater micropollutants by activated sludge and sludge-inherent microorganisms. (United States)

    Fischer, Klaus; Majewsky, Marius


    Municipal wastewaters contain a multitude of organic trace pollutants. Often, their biodegradability by activated sludge microorganisms is decisive for their elimination during wastewater treatment. Since the amounts of micropollutants seem too low to serve as growth substrate, cometabolism is supposed to be the dominating biodegradation process. Nevertheless, as many biodegradation studies were performed without the intention to discriminate between metabolic and cometabolic processes, the specific contribution of the latter to substance transformations is often not clarified. This minireview summarizes current knowledge about the cometabolic degradation of organic trace pollutants by activated sludge and sludge-inherent microorganisms. Due to their relevance for communal wastewater contamination, the focus is laid on pharmaceuticals, personal care products, antibiotics, estrogens, and nonylphenols. Wherever possible, reference is made to the molecular process level, i.e., cometabolic pathways, involved enzymes, and formed transformation products. Particular cometabolic capabilities of different activated sludge consortia and various microbial species are highlighted. Process conditions favoring cometabolic activities are emphasized. Finally, knowledge gaps are identified, and research perspectives are outlined.

  18. Occurrence, distribution, and potential influencing factors of sewage sludge components derived from nine full-scale wastewater treatment plants of Beijing, China. (United States)

    Wang, Xu; Li, Meiyan; Liu, Junxin; Qu, Jiuhui


    Millions of tons of waste activated sludge (WAS) produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critical for sustainable sludge management. In this work, the occurrence and distribution of several fundamental sludge constituents were explored in WAS samples from nine full-scale wastewater treatment plants (WWTPs) of Beijing, China. Among all the components investigated, active heterotrophic biomass was dominant in the samples (up to 9478mg/L), followed by endogenous residues (6736mg/L), extracellular polymeric substances (2088mg/L), and intracellular storage products (464mg/L) among others. Moreover, significant differences (p<0.05) were observed in composition profiles of sludge samples among the studied WWTPs. To identify the potential parameters affecting the variable fractions of sludge components, wastewater source as well as design and operational parameters of WWTPs were studied using statistical methods. The findings indicated that the component fraction of sewage sludge depends more on wastewater treatment alternatives than on wastewater characteristics among other parameters. A principal component analysis was conducted, which further indicated that there was a greater proportion of residual inert biomass in the sludge produced by the combined system of the conventional anaerobic/anoxic/oxic process and a membrane bioreactor. Additionally, a much longer solids retention time was also found to influence the sludge composition and induce an increase in both endogenous inert residues and extracellular polymeric substances in the sludge.

  19. Microbial activities in a vertical-flow wetland system treating sewage sludge with high organic loads

    Energy Technology Data Exchange (ETDEWEB)

    Wang, R. Y.; Perissol, C.; Baldy, V.; Bonin, G.; Korboulewsky, N.


    The rhizosphere is the most active zone in treatment wetlands where take place physicochemical and biological processes between the substrate, plants, microorganisms, and contaminants. Microorganisms play the key role in the mineralisation of organic matter. substrate respiration and phosphatase activities (acid and alkaline) were chosen as indicators of microbial activities, and studied in a vertical-flow wetland system receiving sewage sludge with high organic loads under the Mediterranean climate. (Author)

  20. Feasibility analysis of a sewage sludge treatment by an irradiation plant in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, J.; Balcazar, M. [Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carretera Mexico-Toluca, C.P. 52045 Estado de Mexico (Mexico); Colin, A. [Universidad Autonoma del Estado de Mexico, Toluca (Mexico); Tavera, L. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico)


    Technical and economic analyses of an irradiation plant for sewage sludge treatment determined that an appropriate place for the first sludge electron irradiator in Mexico would be the sewage water treatment plant located north of Toluca in the State of Mexico. This treatment plant is mainly used for domestic wastewater and produces an approximate volume of 70 ton d-] liquid sewage sludge. Considering a 50 k W power of a 10 MeV electron linear accelerator, an irradiation dose of S KGy and a treatment capacity of 346 tons per day, it is estimated that the treatment cost would be of $9.00 US dollars per ton. (Author)

  1. Feasibility analysis of a sewage sludge treatment by an irradiation plant in Mexico

    CERN Document Server

    Moreno, J; Colin, A; Tavera, L


    Technical and economic analyses of an irradiation plant for sewage sludge treatment determined that an appropriate place for the first sludge electron irradiator in Mexico would be the sewage water treatment plant located north of Toluca in the State of Mexico. This treatment plant is mainly used for domestic wastewater and produces an approximate volume of 70 ton d-] liquid sewage sludge. Considering a 50 k W power of a 10 MeV electron linear accelerator, an irradiation dose of S KGy and a treatment capacity of 346 tons per day, it is estimated that the treatment cost would be of $9.00 US dollars per ton. (Author)

  2. Transient Response of Aerobic and Anoxic Activated Sludge Activities to Sudden Substrate Concentration Changes

    DEFF Research Database (Denmark)

    Sin, G.; Vanrolleghem, P.A.; Gernaey, Krist


    The state-of-the-art understanding of activated sludge processes as summarized in activated sludge models (ASMs) predicts an instantaneous increase in the biomass activity (which is measured, e.g., by the corresponding respiration rate OUR, NUR, etc.) under sudden substrate concentration changes...... process. That transient phenomenon exhibits itself immediately upon addition of a substrate source to an endogenously respiring activated sludge sample and it usually takes a few minutes until the activated sludge reaches its maximum possible rate under given environmental conditions. This discrepancy...... response of the activated sludge most likely results from the sequence of intracellular reactions involved in substrate degradation by the activated sludge. Results from studies performed elsewhere with pure cultures (S. cerevisae and E. coli) support the hypothesis. The transient phenomenon can...

  3. System for the Reduction of Substances in Reject Water from Reed-Bed Sludge Mineralization Plants

    DEFF Research Database (Denmark)


    The invention is a system for the reduction of substances in reject water from reed-bed sludge mineralization plants (also referred to as sludge dewatering reed-beds). The systems utilizes the composition of substances in reject water from reed-beds and that of sludge to reduce substance mass from...... within the container. The solution is then applied to the reed-beds, which dewaters, converts, and partially mineralize the sludge mixture. The reject water from the reed-beds is split where up to100% of the reject water is recirculated back to the mixed reactor and the remaining usually disposed...... the reject water via recirculation into a mixed reactor and back onto the reed-beds. The mixed rector consists of a container in which sludge (that is typically loaded directly on to reed-beds) is mixed with recirculated reject water from reed-beds. The sludge mixture has a definable hydraulic retention time...

  4. Fate of cyanobacteria in drinking water treatment plant lagoon supernatant and sludge

    Energy Technology Data Exchange (ETDEWEB)

    Pestana, Carlos J.; Reeve, Petra J.; Sawade, Emma [Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000 (Australia); Voldoire, Camille F. [Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000 (Australia); École Européenne de Chimie, Polymères et Matériaux (ECPM), Strasbourg 67087 (France); Newton, Kelly; Praptiwi, Radisti [Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000 (Australia); Collingnon, Lea [Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000 (Australia); École Européenne de Chimie, Polymères et Matériaux (ECPM), Strasbourg 67087 (France); Dreyfus, Jennifer [Allwater, Adelaide Services Alliance, Wakefield St, Adelaide, SA 5001 (Australia); Hobson, Peter [Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000 (Australia); Gaget, Virginie [University of Adelaide, Ecology and Environmental Sciences, School of Biological Sciences, Adelaide, SA 5005 (Australia); Newcombe, Gayle, E-mail: [Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000 (Australia)


    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 10 days 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. - Highlights: • Cyanobacteria in water treatment sludge significantly impact supernatant quality • Cyanobacteria can survive, and thrive, in sludge lagoon supernatant and in treatment sludge • Metabolite concentrations in cyanobacteria in sludge can increase up to 500% • The risk associated with supernatant recycling was assessed relative to available treatment barriers.

  5. The abundance and diversity of ammonia-oxidizing bacteria in activated sludge under autotrophic domestication. (United States)

    Li, Qiang; Ma, Chao; Sun, Shifang; Xie, Hui; Zhang, Wei; Feng, Jun; Song, Cunjiang


    Ammonia-oxidizing bacteria (AOB) play a key role in nitrogen-removal wastewater treatment plants (WWTPs) as they can transform ammonia into nitrite. AOB can be enriched in activated sludge through autotrophic domestication although they are difficult to be isolated. In this study, autotrophic domestication was carried out in a lab-scale sequencing-batch-reactor (SBR) system with two activated sludge samples. The ammonia removal capacity of the sludge samples increased during the domestication, and pH exhibited a negative correlation with the ammonia removal amount, which indicated that it was one important factor of microbial ammonia oxidation. The count of AOB, measured by the most probable number (MPN) method, increased significantly during autotrophic domestication as ammonia oxidation efficiency was enhanced. We investigated the changes in the community structure of AOB before and after domestication by amoA clone library and T-RFLP profile. It showed that AOB had been successfully enriched and the community structure significantly shifted during the domestication. Two groups of AOB were found in sludge samples: Nitrosomonas-like group remained predominant all the time and Nitrosospira-like group changed obviously. Simultaneously, the total heterotrophic bacteria were investigated by MPN and Biolog assay. The metabolic diversity of heterotrophs had changed minutely, although the count of them decreased significantly and lost superiority of microbial communities in the sludge.

  6. Preference of the green peach aphid, Myzus persicae, for plants grown in sewage sludges

    Energy Technology Data Exchange (ETDEWEB)

    Culliney, T.W.; Pimentel, D.


    Since passage of the Clean Water Act in the 1970s, disposal of the millions of tonnes of sewage sludge generated annually has become a major concern of municipalities throughout the United States. With the range of other disposal options having narrowed in recent years, application of sludge to land is increasingly viewed as a practical and economical means to recycle this waste material. However, sludges from large cities with industries may be contaminated with various toxic chemicals, including polychlorinated biphenyls (PCBs), other organic chemicals, such as pesticides, and heavy metals. Sludge application to land thus has the potential adversely to affect biota and the functioning of terrestrial ecosystems. The authors previously demonstrated marked reductions in fecundity and survival of green peach aphids, Myzus persicae, on collard plants, Brassica oleracea var. sabellica, growing in soil treated with chemically contaminated sludge as compared to aphids on plants growing either in soil treated with uncontaminated sludge of soil conventionally fertilized. Reduced plant growth and increased restlessness in aphids in the contaminated sludge treatment were also observed. The purpose of the present study was to examine more closely the influence of sludge contaminants on aphid settling behavior as indicated by differential preference of M. persicae for leaves of its collard host grown under different soil conditions.

  7. Upflow Sludge Blanket Filtration (USBF: An Innovative Technology in Activated Sludge Process

    Directory of Open Access Journals (Sweden)

    R Saeedi


    Full Text Available Background: A new biological domestic wastewater treatment process, which has been presented these days in activated sludge modification, is Upflow Sludge Blanket Filtration (USBF. This process is aerobic and acts by using a sludge blanket in the separator of sedimentation tank. All biological flocs and suspended solids, which are presented in the aeration basin, pas through this blanket. The performance of a single stage USBF process for treatment of domestic wastewater was studied in laboratory scale.Methods: The pilot of USBF has been made from fiberglass and the main electromechanical equipments consisted of an air com­pressor, a mixing device and two pumps for sludge return and wastewater injection. The wastewater samples used for the experiments were prepared synthetically to have qualitative characteristics similar to a typical domestic wastewater (COD= 277 mg/l, BOD5= 250 mg/l and TSS= 1 mg/l.Results: On the average, the treatment system was capable to remove 82.2% of the BOD5 and 85.7% of COD in 6 h hydraulic re­tention time (HRT. At 2 h HRT BOD and COD removal efficiencies dramatically reduced to 50% and 46.5%, respectively.Conclusion: Even by increasing the concentrations of pollutants to as high as 50%, the removal rates of all pollutants were re­mained similar to the HRT of 6 h.

  8. Anaerobic Codigestion of Municipal Wastewater Treatment Plant Sludge with Food Waste: A Case Study (United States)

    Rajendram, William


    The aim of this study was to assess the effects of the codigestion of food manufacturing and processing wastes (FW) with sewage sludge (SS), that is, municipal wastewater treatment plant primary sludge and waste activated sludge. Bench scale mesophilic anaerobic reactors were fed intermittently with varying ratio of SS and FW and operated at a hydraulic retention time of 20 days and organic loading of 2.0 kg TS/m3·d. The specific biogas production (SBP) increased by 25% to 50% with the addition of 1%–5% FW to SS which is significantly higher than the SBP from SS of 284 ± 9.7 mLN/g VS added. Although the TS, VS, and tCOD removal slightly increased, the biogas yield and methane content improved significantly and no inhibitory effects were observed as indicated by the stable pH throughout the experiment. Metal screening of the digestate suggested the biosolids meet the guidelines for use as a soil conditioner. Batch biochemical methane potential tests at different ratios of SS : FW were used to determine the optimum ratio using surface model analysis. The results showed that up to 47-48% FW can be codigested with SS. Overall these results confirm that codigestion has great potential in improving the methane yield of SS. PMID:27689091

  9. Anaerobic Codigestion of Municipal Wastewater Treatment Plant Sludge with Food Waste: A Case Study

    Directory of Open Access Journals (Sweden)

    Zubayeda Zahan


    Full Text Available The aim of this study was to assess the effects of the codigestion of food manufacturing and processing wastes (FW with sewage sludge (SS, that is, municipal wastewater treatment plant primary sludge and waste activated sludge. Bench scale mesophilic anaerobic reactors were fed intermittently with varying ratio of SS and FW and operated at a hydraulic retention time of 20 days and organic loading of 2.0 kg TS/m3·d. The specific biogas production (SBP increased by 25% to 50% with the addition of 1%–5% FW to SS which is significantly higher than the SBP from SS of 284±9.7 mLN/g VS added. Although the TS, VS, and tCOD removal slightly increased, the biogas yield and methane content improved significantly and no inhibitory effects were observed as indicated by the stable pH throughout the experiment. Metal screening of the digestate suggested the biosolids meet the guidelines for use as a soil conditioner. Batch biochemical methane potential tests at different ratios of SS : FW were used to determine the optimum ratio using surface model analysis. The results showed that up to 47-48% FW can be codigested with SS. Overall these results confirm that codigestion has great potential in improving the methane yield of SS.

  10. Estimates of Radiation Dose Rates Near Large Diameter Sludge Containers in T Plant

    CERN Document Server

    Himes, D A


    Dose rates in T Plant canyon during the handling and storage of large diameter storage containers of K Basin sludge were estimated. A number of different geometries were considered from which most operational situations of interest can be constructed.

  11. Water Treatment Plant Sludges--An Update of the State of the Art: Part 2. (United States)

    American Water Works Association Journal, 1978


    This report outlines the state of the art with respect to nonmechanical and mechanical methods of dewatering water treatment plant sludge, ultimate solids disposal, and research and development needs. (CS)

  12. Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge. (United States)

    Rodriguez-Perez, S; Fermoso, F G; Arnaiz, C

    Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.

  13. Oxygen transfer dynamics and activated sludge floc structure under different sludge retention times at low dissolved oxygen concentrations. (United States)

    Fan, Haitao; Liu, Xiuhong; Wang, Hao; Han, Yunping; Qi, Lu; Wang, Hongchen


    In activated sludge systems, the aeration process consumes the most energy. The energy cost can be dramatically reduced by decreasing the operating dissolved oxygen (DO) concentration. However, low DO may lead to incomplete nitrification and poor settling performance of activated sludge flocs (ASFs). This study investigates oxygen transfer dynamics and settling performances of activated sludge under different sludge retention times (SRTs) and DO conditions using microelectrodes and microscopic techniques. Our experimental results showed that with longer SRTs, treatment capacity and settling performances of activated sludge improved due to smaller floc size and less extracellular polymeric substances (EPS). Long-term low DO conditions produced larger flocs and more EPS per unit sludge, which produced a more extensive anoxic area and led to low oxygen diffusion performance in flocs. Long SRTs mitigated the adverse effects of low DO. According to the microelectrode analysis and fractal dimension determination, smaller floc size and less EPS in the long SRT system led to high oxygen diffusion property and more compact floc structure that caused a drop in the sludge volume index (SVI). In summary, our results suggested that long SRTs of activated sludge can improve the operating performance under low DO conditions.

  14. Analysis of bacterial community structures in two sewage treatment plants with different sludge properties and treatment performance by nested PCR-DGGE method

    Institute of Scientific and Technical Information of China (English)

    LIU Xin-chun; ZHANG Yu; YANG Min; WANG Zhen-yu; LV Wen-zhou


    The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis (DGGE) of nested polymerase chain reaction (nested PCR) amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated sludge samples were amplified using the extracted genomic DNA before the PCR products were loaded on the same DGGE gel for bacterial community analysis. Ammonia-oxidizing bacterial and actinomycetic community analysis were also carried out to investigate the relationship between specific population structures and system or sludge performance. The two plants demonstrated a similarity in bacterial community structures of raw sewage and activated sludge, but they had different effluent populations. Many dominant bacterial populations of raw sewage did not appear in the activated sludge samples, suggesting that the dominant bacterial populations in raw sewage might not play an important role during wastewater treatment. Although the two plants had different sludge properties in terms of settleability and foam forming ability, they demonstrated similar actinomycetic community structures. For activated sludge with bad settling performance, the treated water presented a similar DGGE pattern with that of activated sludge, indicating the nonselective washout of bacteria from the system. The plant with better ammonium removal efficiency showed higher ammonia-oxidizing bacteria (AOB) species richness. Analysis of sequencing results showed that the major populations in raw sewage were uncultured bacterium, while in activated sludge the predominant populations were beta proteobacteria.

  15. Eikelboom's morphotype 0803 in activated sludge belongs to the genus Caldilinea in the phylum Chloroflexi. (United States)

    Kragelund, Caroline; Thomsen, Trine Rolighed; Mielczarek, Artur Tomasz; Nielsen, Per Halkjaer


    Micromanipulated filamentous bacteria from bulking and foaming activated sludge morphologically identified as Eikelboom type 0803 were shown to be affiliated to the genus Caldilinea within the phylum Chloroflexi. Specific FISH probes were designed for their in situ detection and quantification in seven Danish wastewater treatment plants with biological nutrient removal. The survey applied all species-specific probes for Chloroflexi of relevance in activated sludge treatment plants as well as the phylum-specific probes. Type 0803 filaments constituted around 20% of the total Chloroflexi population. In four of the treatment plants, type 0803 and type 0092 co-occurred and were the dominating fraction of the Chloroflexi population. In the other plants, most Chloroflexi could not be identified beyond the phylum level, suggesting a yet far larger diversity. On average, for all plants, the total Chloroflexi population constituted 12% of the entire microbial population and seems to play an important structural role in the sludge floc formation. Ecophysiological characterization of type 0803 showed their potential role in macromolecule conversion as evident by high levels of exoenzyme expression. Acetate was not consumed. Glucose was consumed with oxygen, nitrite and nitrite as electron acceptors, suggesting that type 0803 may be a denitrifier. Their surfaces were hydrophobic, explaining their occasional occurrence in foaming incidents.

  16. The Microbial Database for Danish wastewater treatment plants with nutrient removal (MiDas-DK) – a tool for understanding activated sludge population dynamics and community stability

    DEFF Research Database (Denmark)

    Mielczarek, Artur Tomasz; Saunders, Aaron Marc; Larsen, Poul


    ecosystems, and, besides many scientific articles on fundamental issues on mixed communities encompassing nitrifiers, denitrifiers, bacteria involved in P-removal, hydrolysis, fermentation, and foaming, the project has provided results that can be used to optimize the operation of full-scale plants and carry...... plants, there seemed to be plant-specific factors that controlled the population composition thereby keeping it unique in each plant over time. Statistical analyses of FISH and operational data revealed some correlations, but less than expected. MiDas-DK ( will continue over the next years...


    Energy Technology Data Exchange (ETDEWEB)



    The Sludge Treatment Project (STP) is responsible for the disposition of sludge contained in the six engineered containers and Settler tank within the 105-K West (KW) Basin. The STP is retrieving and transferring sludge from the Settler tank into engineered container SCS-CON-230. Then, the STP will retrieve and transfer sludge from the six engineered containers in the KW Basin directly into a Sludge Transport and Storage Containers (STSC) contained in a Sludge Transport System (STS) cask. The STSC/STS cask will be transported to T Plant for interim storage of the STSC. The STS cask will be loaded with an empty STSC and returned to the KW Basin for loading of additional sludge for transportation and interim storage at T Plant. CH2MHILL Plateau Remediation Company (CHPRC) contracted with Fauske & Associates, LLC (FAI) to perform thermal and gas generation analyses for interim storage of STP sludge in the Sludge Transport and Storage Container (STSCs) at T Plant. The sludge types considered are settler sludge and sludge originating from the floor of the KW Basin and stored in containers 210 and 220, which are bounding compositions. The conditions specified by CHPRC for analysis are provided in Section 5. The FAI report (FAI/10-83, Thermal and Gas Analyses for a Sludge Transport and Storage Container (STSC) at T Plant) (refer to Attachment 1) documents the analyses. The process considered was passive, interim storage of sludge in various cells at T Plant. The FATE{trademark} code is used for the calculation. The results are shown in terms of the peak sludge temperature and hydrogen concentrations in the STSC and the T Plant cell. In particular, the concerns addressed were the thermal stability of the sludge and the potential for flammable gas mixtures. This work was performed with preliminary design information and a preliminary software configuration.

  18. Extractable Fractions of Metals in Sewage Sludges from Five Typical Urban Wastewater Treatment Plants of China

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; LI Xiao-Chen; WANG Pei-Fang; ZOU Li-Min; MA Hai-Tao


    Metal content and bioavailability are often the limiting factors for application of sewage sludge in agricultural fields.Sewage sludge samples were collected from five typical urban wastewater treatment plants in China to investigate their contents and distribution of various chemical fractions of Cu, Zn, Ni, Cr, Pb and Mo by using the BCR (Community Bureau of Reference) sequential extraction procedure. The sludges contained considerable amounts of organic matter (31.8%-48.0%), total N (16.3-26.4 g kg-1) and total P (15.1-23.9 g kg-1), indicating high potential agricultural benefits of their practical applications. However, total Zn and Ni contents in the sludge exceeded the values permitted in China's control standards for pollutants in sludges from agricultural use (GB 4284-1984). The residual fraction was the predominant fraction for Mo, Ni and Cr, the oxidizable fraction was the primary fraction for Cu and Pb, and the exchangeable and reducible fractions were principal for Zn. The distribution of different chemical fractions among the sludge samples reflected differences in their physicochemical properties, especially pH. The sludge pH was negatively correlated with the percentages of reducible fraction of Cu and exchangeable fraction of Zn. The sludges from these plants might not be suitable for agricultural applications due to their high contents of Zn, Ni and Cr, as well as high potential of mobility and bioavailability of Zn.

  19. Use of lysis and recycle to control excess sludge production in activated sludge treatment: bench scale study and effect of chlorinated organic compounds. (United States)

    Nolasco, M A; Campos, A L O; Springer, A M; Pires, E C


    The most widely used treatment system in the pulp and paper industry--the activated sludge--produces high quantities of sludge which need proper disposal. In this paper a modified activated sludge process is presented. A synthetic wastewater, prepared to simulate the effluent of bleached and unbleached pulp and paper plant wastewater, was submitted to treatment in a bench scale aerobic reactor. The excess sludge was lysed in a mechanical mill--Kaddy mill--and totally recycled to the aeration tank. In the first phase the synthetic wastewater, without the chlorinated compounds, was fed to the reactor. In the second phase increasing dosages of the chlorinated compounds were used. Total recycle of excess sludge after disintegration did not produce adverse effects. During the first phase average COD removal efficiency was 65% for the control unit, which operated in a conventional way, and 63% for the treatment unit, which operated with total recycle. During the second phase the COD removal efficiency increased to 77% in the control unit and 75% in the treatment unit. Chlorinated organics removal was 85% in the treatment unit and 86% for the control unit. These differences are not significant.

  20. Metaproteomics provides functional insight into activated sludge wastewater treatment.

    Directory of Open Access Journals (Sweden)

    Paul Wilmes

    Full Text Available BACKGROUND: Through identification of highly expressed proteins from a mixed culture activated sludge system this study provides functional evidence of microbial transformations important for enhanced biological phosphorus removal (EBPR. METHODOLOGY/PRINCIPAL FINDINGS: A laboratory-scale sequencing batch reactor was successfully operated for different levels of EBPR, removing around 25, 40 and 55 mg/l P. The microbial communities were dominated by the uncultured polyphosphate-accumulating organism "Candidatus Accumulibacter phosphatis". When EBPR failed, the sludge was dominated by tetrad-forming alpha-Proteobacteria. Representative and reproducible 2D gel protein separations were obtained for all sludge samples. 638 protein spots were matched across gels generated from the phosphate removing sludges. 111 of these were excised and 46 proteins were identified using recently available sludge metagenomic sequences. Many of these closely match proteins from "Candidatus Accumulibacter phosphatis" and could be directly linked to the EBPR process. They included enzymes involved in energy generation, polyhydroxyalkanoate synthesis, glycolysis, gluconeogenesis, glycogen synthesis, glyoxylate/TCA cycle, fatty acid beta oxidation, fatty acid synthesis and phosphate transport. Several proteins involved in cellular stress response were detected. CONCLUSIONS/SIGNIFICANCE: Importantly, this study provides direct evidence linking the metabolic activities of "Accumulibacter" to the chemical transformations observed in EBPR. Finally, the results are discussed in relation to current EBPR metabolic models.

  1. Evaluating the Measurement of Activated Sludge Foam Potential

    Directory of Open Access Journals (Sweden)

    Eoghan O’Flaherty


    Full Text Available The most widely used technique for assessing the propensity of activated sludge to suffer from biological foaming is to measure foam potential. This involves measuring the amount of foam produced from sludge under conditions of controlled aeration. Two approaches have been adopted: (1 Air is passed through specially designed columns from fine porous diffusers at a fixed rate to form uniform sized bubbles or (2 employing Alka-Seltzer™ tablets which effervesce when added to the sludge. Both tests generate foam formation which can then be quantified. Foam assessment in activated sludge is reviewed. A sintered disc aeration column was compared with the Alka-Seltzer™ test method and both methods examined under a range of different environmental conditions. Foam potential measured by the sintered disc method displayed better repeatability compared to the Alka-Seltzer test. The use of a wire cage placed over the tablets greatly improved the precision of the Alka-Seltzer test. A positive linear correlation was also found between foam potential and temperature (4–20 °C. Sludge solids concentration was also shown to influence foaming potential making comparisons between reactors problematic. Recommendations on how to improve the repeatability of foam potential measurements are given.

  2. Particulate and colloidal silver in sewage effluent and sludge discharged from British wastewater treatment plants. (United States)

    Johnson, Andrew C; Jürgens, Monika D; Lawlor, Alan J; Cisowska, Iwona; Williams, Richard J


    Differential filtration was used to measure silver (>2 nm) entering and leaving nine sewage treatment plants (STPs). The mean concentration of colloidal (2-450 nm) silver, which includes nanosilver, was found to be 12 ng L(-1) in the influent and 6 ng L(-1) in the effluent. For particulate silver (>450 nm) the mean values were 3.3 μg L(-1) for influent and 0.08 μg L(-1) for effluent. Thus, removal was around 50% and 98% for colloidal and particulate silver respectively. There was no significant difference in performance between the different types of STP investigated (three examples each of activated sludge, biological filter and biological filter with tertiary treatment located across England, UK). In addition, treated sewage sludge samples (biosolids) were taken from several STPs to measure the total silver likely to be discharged to soils. Total silver was 3-14 mg kg(-1) DW in the sludge (median 3.6), which if the sludge were added at the recommended rate to soil, would add 11 μg kg(-1) yr(-1) to the top 20 cm soil layer. Predicted concentrations using the LF2000-WQX model for all the rivers of England and Wales for nanosilver were typically in the 0-1 ng L(-1) range but levels up to 4 ng L(-1) are possible in a high discharge and low flow scenario. Predicted concentrations for the total particulate forms were mostly below 50 ng L(-1) except for a high discharge and low flow scenario where concentrations could reach 135 ng L(-1).

  3. Nitrate control strategies in an activated sludge wastewater treatment process

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wenhao; Tao, Erpan; Chen, Xiaoquan; Liu, Dawei [South China University of Technology, Guangzhou (China); Liu, Hongbin [Kyung Hee University, Yongin (Korea, Republic of)


    We studied nitrate control strategies in an activated sludge wastewater treatment process (WWTP) based on the activated sludge model. Two control strategies, back propagation for proportional-integral-derivative (BP-PID) and adaptive-network based fuzzy inference systems (ANFIS), are applied in the WWTP. The simulation results show that the simple local constant setpoint control has poor control effects on the nitrate concentration control. However, the ANFIS (4*1) controller, which considers not only the local constant setpoint control of the nitrate concentration, but also three important indices in the effluent--ammonia concentration, total suspended sludge concentration and total nitrogen concentration--demonstrates good control performance. The results also prove that ANFIS (4*1) controller has better control performance than that of the controllers PI, BP-PID and ANFIS (2*1), and that the ANFIS (4*1) controller is effective in improving the effluent quality and maintaining the stability of the effluent quality.

  4. Thermal sludge dryer demonstration: Bird Island Wastewater Treatment Plant, Buffalo, NY. Final report

    Energy Technology Data Exchange (ETDEWEB)



    The Buffalo Sewer Authority (BSA), in cooperation with the New York State Energy Research and Development Authority (Energy Authority), commissioned a demonstration of a full scale indirect disk-type sludge dryer at the Bird Island Wastewater Treatment Plant (BIWWTP). The purpose of the project was to determine the effects of the sludge dryer on the sludge incineration process at the facility. Sludge incineration is traditionally the most expensive, energy-intensive unit process involving solids handling at wastewater treatment plants; costs for incineration at the BIWWTP have averaged $2.4 million per year. In the conventional method of processing solids, a series of volume reduction measures, which usually includes thickening, digestion, and mechanical dewatering, is employed prior to incineration. Usually, a high level of moisture is still present within sewage sludge following mechanical dewatering. The sludge dryer system thermally dewaters wastewater sludge to approximately 26%, (and as high as 38%) dry solids content prior to incineration. The thermal dewatering system at the BIWWTP has demonstrated that it meets its design requirements. It has the potential to provide significant energy and other cost savings by allowing the BSA to change from an operation employing two incinerators to a single incinerator mode. While the long-term reliability of the thermal dewatering system has yet to be established, this project has demonstrated that installation of such a system in an existing treatment plant can provide the owner with significant operating cost savings.

  5. Microwave pyrolysis of oily sludge with activated carbon. (United States)

    Chen, Yi-Rong


    The aim of this study is to explore catalytic microwave pyrolysis of crude oil storage tank sludge for fuels using granular activated carbon (GAC) as a catalyst. The effect of GAC loading on the yield of pyrolysis products was also investigated. Heating rate of oily sludge and yield of microwave pyrolysis products such as oil and fuel gas was found to depend on the ratio of GAC to oily sludge. The optimal GAC loading was found to be 10%, while much smaller and larger feed sizes adversely influenced production. During oily sludge pyrolysis, a maximum oil yield of 77.5% was achieved. Pyrolytic oils with high concentrations of diesel oil and gasoline (about 70 wt% in the pyrolytic oil) were obtained. The leaching of heavy metals, such as Cr, As and Pb, was also suppressed in the solid residue after pyrolysis. This technique provides advantages such as harmless treatment of oily sludge and substantial reduction in the consumption of energy, time and cost.

  6. Effects of TiO2 and Ag nanoparticles on polyhydroxybutyrate biosynthesis by activated sludge bacteria. (United States)

    Priester, John H; Van De Werfhorst, Laurie C; Ge, Yuan; Adeleye, Adeyemi S; Tomar, Shivira; Tom, Lauren M; Piceno, Yvette M; Andersen, Gary L; Holden, Patricia A


    Manufactured nanomaterials (MNMs) are increasingly incorporated into consumer products that are disposed into sewage. In wastewater treatment, MNMs adsorb to activated sludge biomass where they may impact biological wastewater treatment performance, including nutrient removal. Here, we studied MNM effects on bacterial polyhydroxyalkanoate (PHA), specifically polyhydroxybutyrate (PHB), biosynthesis because of its importance to enhanced biological phosphorus (P) removal (EBPR). Activated sludge was sampled from an anoxic selector of a municipal wastewater treatment plant (WWTP), and PHB-containing bacteria were concentrated by density gradient centrifugation. After starvation to decrease intracellular PHB stores, bacteria were nutritionally augmented to promote PHB biosynthesis while being exposed to either MNMs (TiO2 or Ag) or to Ag salts (each at a concentration of 5 mg L(-1)). Cellular PHB concentration and PhyloChip community composition were analyzed. The final bacterial community composition differed from activated sludge, demonstrating that laboratory enrichment was selective. Still, PHB was synthesized to near-activated sludge levels. Ag salts altered final bacterial communities, although MNMs did not. PHB biosynthesis was diminished with Ag (salt or MNMs), indicating the potential for Ag-MNMs to physiologically impact EBPR through the effects of dissolved Ag ions on PHB producers.

  7. Specific methanogenic activity (SMA of industrial sludge from the aerobic and anaerobic biological treatment

    Directory of Open Access Journals (Sweden)

    Danieli Schneiders


    Full Text Available In this study, specific methanogenic activity (SMA tests were performed on textile sludge and food industry sludge. The textile sludge from an activated sludge was collected at the entrance of the secondary biologic clarifier and the food sludge was collected in a UASB reactor. Once collected, the sludges were characterized and tested for SMA. It was found that the microrganisms present in the food sludge had SMA of 0.17 gCOD-CH4 gSSV.d-1 and 337.05 mL of methane production, while the microrganisms of the textile sludge presented 0.10 gCOD-CH4 gSSV.d-1 of SMA and 3.04 mL of methane production. Therefore, the food sludge was more suitable to be used as a starting inoculum in UASB.

  8. Ecotoxicity Assessment of Stabilized Sewage Sludge from Municipal Sewage Treatment Plant (United States)

    Włodarczyk, Elżbieta; Próba, Marta; Wolny, Lidia


    Aim of this study was to evaluate the ecotoxicity of municipal sewage sludge conditioned with polyelectrolytes, taken from selected sewage treatment plant. Using the bioindication analysis overall toxicity was assessed, which allows to know the total toxicity of all the harmful substances contained in sewage sludge, in many cases acting synergistically. To prepare a sample of sludge for the basic test, all analyses were performed with a ratio of liquid to solid of 10:1 (water extract). Daphnia pulex biological screening test was used. A dilution series of an water extract of sludge were prepared to include within its scope the lowest concentration that causes 100% effect and the highest producing less than 10% of the effect within a specified range of the assay. The results of the test were read after 24 and 48 hours. Based on the research and analysis of test results it proved that the sewage sludge conditioned with polyelectrolytes exhibit the characteristics of eco-toxic.

  9. Disinfection of raw wastewater and activated sludge effluent using Fenton like reagent


    Aslani, Hassan; Nabizadeh, Ramin; Alimohammadi, Mahmood; MESDAGHINIA, Alireza; Nadafi, Kazem; Nemati, Reza; Ghani, Maryam


    Background and objectives Water shortage problems have led to find either new water resources or improve wastewater treatment technologies in order to reuse. Due to less performance of previous units in microbial removal, disinfection has become a necessary step in wastewater treatment plants. In the present study performance of hydrogen peroxide (HP) and modified Fenton’s reagent (HP + Cu++) was considered for the disinfection of raw wastewater (RW) and activated sludge effluent (ASE). Mater...

  10. Rapid determination of filamentous microorganisms in activated sludge; Determinacion rapida de microorganismos filamentosos en fangos activados

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C.; Jimenez, C.; Estevez, F. [Empresa Municipal de Abastecimiento y Saneamiento de Aguas de Sevilla (Spain)


    Despite many methods available biomass estimation of a bioprocess may sometimes become laborious and impracticable. Samples containing filamentous organisms, as in Wastewater Treatment Plants, present special counting difficulties. If they are abundant they may need to be estimated separately. In this work a counting method for these organisms is show. The main goal is to improve chlorination of activated sludge suffering bulking or foaming through a quantitative record of filamentous bacteria. (Author) 12 refs.

  11. Effect of process variables on the production of Polyhydroxyalkanoates by activated sludge

    Directory of Open Access Journals (Sweden)

    Mokhtarani Nader


    Full Text Available Abstract Polyhydroxyalkanoates are known to be temporarily stored by microorganisms in activated sludge, especially in anaerobic-aerobic processes. Due to the problems resulted from the disposals of plastic wastes and excess sludge of wastewater treatment plants, the production of polyhydroxyalkanoates by treating activated sludge and determining the effect of process variables were the main issues of this paper. In this research, an anaerobic-aerobic sequencing batch reactor was used to make microorganism adapted and a batch aerobic reactor was used for enriching them. The variables affecting polyhydroxyalkanoates production including aeration time, sludge retention time, and volatile fatty acids concentration of the influent in sequencing batch reactor, and also carbon to nitrogen ratio and cultivation time in polymer production reactor, were investigated using Taguchi statistical approach to determine optimum conditions. The maximum polymer production of 29% was achieved at sludge retention time of 5–10 days, aeration time of 2 hours, supplementation of 40% of volatile fatty acids in the influent and increasing of carbon to nitrogen ratio of polymer production reactor to above 25 g/g. Based on the results, in optimum conditions, the volatile fatty acids concentration which increased the production of polyhydroxyalkanoates up to 49% was the most effective variable. Carbon to nitrogen ratio, sludge retention time and aeration time were ranked as the next affecting parameters. Although the polyhydroxyalkanoates content achieved in present study is much lower than that by pure culture, but the proposed method may still serve well as an environmental friendly means to convert waste into valuable product.

  12. Effect of Process Variables on the Production of Polyhydroxyalkanoates by Activated Sludge

    Directory of Open Access Journals (Sweden)

    Nader Mokhtarani


    Full Text Available Polyhydroxyalkanoates are known to be temporarily stored by microorganisms in activated sludge, especially in anaerobic-aerobic processes. Due to the problems resulted from the disposals of plastic wastes and excess sludge of wastewater treatment plants, the production of polyhydroxyalkanoates by treating activated sludge anddetermining the effect of process variables were the main issues of this paper. In this research, an anaerobic-aerobic sequencing batch reactor was used to make microorganism adapted and a batch aerobic reactor was used for enriching them. The variables affecting polyhydroxyalkanoates production including aeration time, sludge retention time, and volatile fatty acids concentration of the influent in sequencing batch reactor, and also carbon to nitrogenratio and cultivation time in polymer production reactor, were investigated using Taguchi statistical approach to determine optimum conditions. The maximum polymer production of 29% was achieved at sludge retention time of 5–10 days, aeration time of 2 hours, supplementation of 40% of volatile fatty acids in the influent and increasing of carbon to nitrogen ratio of polymer production reactor to above 25 g/g. Based on the results, in optimum conditions, the volatile fatty acids concentration which increased the production of polyhydroxyalkanoates up to 49% was the most effective variable. Carbon to nitrogen ratio, sludge retention time and aeration time were ranked as the next affecting parameters. Although the polyhydroxyalkanoates content achieved in present study is muchlower than that by pure culture, but the proposed method may still serve well as an environmental friendly means to convert waste into valuable product.

  13. Microscopic Analysis of Plankton, Periphyton, and Activated Sludge. Training Manual. (United States)

    Environmental Protection Agency, Washington, DC. Office of Water Programs.

    This manual is intended for professional personnel in the fields of water pollution control, limnology, water supply and waste treatment. Primary emphasis is given to practice in the identification and enumeration of microscopic organisms which may be encountered in water and activated sludge. Methods for the chemical and instrumental evaluation…

  14. Theoretical and practical aspects of modelling activated sludge processes

    NARCIS (Netherlands)

    Meijer, S.C.F.


    This thesis describes the full-scale validation and calibration of a integrated metabolic activated sludge model for biological phosphorus removal. In chapters 1 and 2 the metabolic model is described, in chapters 3 to 6 the model is tested and in chapters 7 and 8 the model is put into practice. Cha

  15. Options for reducing oil content of sludge from a petroleum wastewater treatment plant. (United States)

    Kwon, Tae-Soon; Lee, Jae-Young


    Wastewater treatment plants at petroleum refineries often produce substantial quantities of sludge with relatively high concentrations of oil. Disposal of this waste is costly, in part because the high oil content requires use of secure disposal methods akin to handling of hazardous wastes. This article examines the properties of oily sludge and evaluates optional methods for reducing the oil content of this sludge to enable use of lower cost disposal methods. To reduce the oil content or break the structure of oily sludge, preliminary lab-scale experiments involving mechanical treatment, surfactant extraction, and oxidation are conducted. By applying surfactants, approximately 36% to 45% of oils are extracted from oily sludge. Of this, about 33% of oils are rapidly oxidised via radiation by an electron beam within 10 s of exposure. The Fenton reaction is effective for destruction of oily sludge. It is also found that 56% of oils were removed by reacting oily sludge with water containing ozone of 0.5 mg l(-1) over a period of 24 h. Oxidation using ozone thus can also be effectively used as a pretreatment for oily sludge.

  16. Biosorption behaviors of Cu2+,Zn2+, Cd2+ and mixture by waste activated sludge

    Institute of Scientific and Technical Information of China (English)

    LUO Sheng-lian; YUAN Lin; CHAI Li-yuan; MIN Xiao-bo; WANG Yun-yan; FANG Yan; WANG Pu


    Biosorption of heavy metal ions, such as Cu2+, Cd2+ and Zn2+, was carried out using waste activated sludge from municipal sewage treatment plant as adsorption material, and the effects of parameters, such as pH value, temperature, reaction time and sorption duration, were studied in detail. The results indicate that the removal rates of Cu2+, Zn2+ and Cd2+ with low concentration are 96.47%, 80% and 90%, respectively, adsorbed by waste activated sludge. Little effect of dosage of activated sludge on the adsorption of Cu2+ and more effects on the adsorption of Zn2+ and Cd2+ are observed. Little effect oftemperature is observed, while pH value and adsorption time exert important influence on the sorption process. The adsorption behaviors of heavy metal ions all have parabolic relationships with pH value. The optimum pH value is between 6 and 10, and the optimum adsorption time is 1 h. In single heavy metal ion system, the sorption processes of Cu2+, Zn2+ and Cd2+ are in accordance with Freundlich model, which indicates that it is suitable for the treatment of these three heavy metal ions using intermittent operation. In addition, the sorption capacity of the sludge for Cu2+ is preferential to the other two ions.

  17. Different options for metal recovery after sludge decontamination at the Montreal Urban Community wastewater treatment plant. (United States)

    Meunier, N; Blais, J F; Lounès, M; Tyagi, R D; Sasseville, J L


    The MUG (Montreal Urban Community) treatment plant produces approximately 270 tons of dry sludge daily (270 tds/day) during the physico-chemical treatment of wastewater. Recently, this treatment plant endowed a system of drying and granulation of sludge for valorization as an agricultural fertilizer having a capacity of 70 tds/day (25% of the daily sludge production). However, the metal content (mainly Cu and Cd) of the sludge surpasses the norms for biosolids valorization. In order to solve this problem, a demonstration project, from the lab scale to the industrial pilot plant, was carried out to test the Metix-AC technology for the removal of metals. A strongly metal-loaded filtrate was generated during the sludge decontamination. Tests concerned the study of the metal recovery by total precipitation and selective precipitation, as well as the use of alternative products for the metal precipitation. Other works consisted to simulate the acid filtrate recirculation from the decontaminated sludge (25% of the total volume) in the untreated sludge (75% of the total volume) intended for the incineration. The total precipitation with hydrated limeappearedeffectivefortherecoveryof metals (87% Cd, 96% Cr, 97% Cu, 98% Fe, 71% Ni, 100% Pb, 98% Zn). However, this option entails the production of an important quantity of metallic residue, which should be disposed of expensively as dangerous material. The selective iron precipitation does not appear to bean interesting option because the iron in solution within the leached sludge was principally present in the form of ferrous iron, which cannot be precipitated at pH lower than five. On the other hand, the use of commercial precipitating agents (TMT-15, CP-33Z, CP-NB and CPX) without pH adjustment of filtrate gave good results for the recovery of Cu and, to a lesser degree for the recovery of Pb. However, the efficiency for the other metals' (Cd, Cr, Fe, Ni and Zn) recovery was weaker (< 25%). Finally, the acid filtrate

  18. Mineralogy and metals speciation in Mo rich mineral sludges generated at a metal recycling plant. (United States)

    Vemic, M; Bordas, F; Guibaud, G; Joussein, E; Labanowski, J; Lens, P N L; van Hullebusch, E D


    In France, more than 250 million metric tons of sludges need to be treated each year. These sludges are either dumped on the landfills or reused as secondary resources in order to preserve natural resources. A large portions of these sludges are mineral sludges, originating from metal recycling plants. In order to estimate their metal recovery potential, these mineral sludges were characterized. Four types of mineral sludge samples were collected from a metal recycling plant (3 from the recycling plant storage areas (bulk storage, barrel storage and storage shed) and 1 from the collection basin). The sludges were characterized, wherein the Mo, Ni, Cr, Co, Zn and W content and speciation were quantified. The samples had pH values between 5.9 and 10.3 with organic matter contents varying between 6.3% (storage shed) and 29.5% (bulk storage) (loss on ignition at 500 °C). Based on their leaching properties, the four mineral sludge samples (in the case of Mo) and the bulk storage sludge (in the case of Ni and Zn) were classified as potentially hazardous regarding the EN 12457-1 and EN 12457-2 method. Mineralogical results reveal that both bulk storage and the storage shed give the highest contributions to the metal content of the collection basin sample. Sequential extraction of the collection basin samples indicated that Mo is bound to the oxidizable and residual fraction, while Ni, Cr and Co were bound to the residual fraction, and Zn to the soluble acid fraction, respectively. W tends to be equally distributed among all extracted fractions. A strong correlation existed between Mo and Co, as well as between Ni, Zn and Cr, respectively.

  19. Parasite contamination (helminth eggs) in sludge treatment plants: definition of a sampling strategy. (United States)

    Gaspard, Philippe G; Schwartzbrod, Janine


    The use of sludge in agriculture must be carried out according to many guidelines, especially regarding a precise knowledge of the pathogenic microorganisms it contains. The control of the produced sludge requires a sampling strategy that is representative of the contamination present in the sludge. Thus, we evaluated the distribution of helminth eggs in sludge to determine how to sample and at what frequency. Two plants were studied, firstly we studied sludge that was undergoing biological treatment (anaerobic digestion, prolonged aeration), secondly we evaluated the dehydration step (centrifugation and filter press). The helminth egg concentrations were measured over short periods (between 5 minutes and 7 hours) and for periods of over 24 hours (7 to 28 days). The results showed that there was much homogeneity in periods of less than 7 hours, thus it was advisable to take grab samples. An appropriate sample weight was 30 g dry matter, because this allowed an analysis in triplicate when testing treatment processes according to standards of France, (less than 3 viable eggs/10 g dry matter). Determination of the egg concentration in the plants during periods of over 24 hours showed that the parasite flow was stable. In some cases, large variations were due to the treatment processes (storage or thickening, mixing of different sludges). These results have been confirmed with the study of 6 other plants during a one year period. Thus, the recommended sampling frequency can be limited to every 3 to 6 months, by adapting the sampling methods to the characteristics of the plant.

  20. Concentrations and speciation of heavy metals in sludge from nine textile dyeing plants. (United States)

    Liang, Xin; Ning, Xun-an; Chen, Guoxin; Lin, Meiqing; Liu, Jingyong; Wang, Yujie


    The safe disposal of sludge from textile dyeing industry requires research on bioavailability and concentration of heavy metals. In this study, concentrations and chemical speciation of heavy metals (Cd, Cr, Cu, Ni, Zn, Pb) in sludge from nine different textile dyeing plants were examined. Some physiochemical features of sludge from textile dyeing industry were determined, and a sequential extraction procedure recommended by the Community Bureau of Reference (BCR) was used to study the metal speciation. Cluster analysis (CA) and principal component analysis (PCA) were applied to provide additional information regarding differences in sludge composition. The results showed that Zn and Cu contents were the highest, followed by Ni, Cr, Cd and Pb. The concentration of Cd and Ni in some sludge samples exceeded the standard suggested for acidic soils in China (GB18918-2002). In sludge from textile dyeing plants, Pb, Cd and Cr were principally distributed in the oxidizable and residual fraction, Cu in the oxidizable fraction, Ni in all four fractions and Zn in the acid soluble/exchangeable and reducible fractions. The pH and heat-drying method affected the fractionation of heavy metals in sludge.

  1. Activated sludge systems removal efficiency of veterinary pharmaceuticals from slaughterhouse wastewater. (United States)

    Carvalho, Pedro N; Pirra, António; Basto, M Clara P; Almeida, C Marisa R


    The knowledge on the efficiency of wastewater treatment plants (WWTPs) from animal food production industry for the removal of both hormones and antibiotics of veterinary application is still very limited. These compounds have already been reported in different environmental compartments at levels that could have potential impacts on the ecosystems. This work aimed to evaluate the role of activated sludge in the removal of commonly used veterinary drugs, enrofloxacin (ENR), tetracycline (TET), and ceftiofur, from wastewater during a conventional treatment process. For that, a series of laboratory-controlled experiments using activated sludge were carried out in batch reactors. Sludge reactors with 100 μg/L initial drug charge presented removal rates of 68 % for ENR and 77 % for TET from the aqueous phase. Results indicated that sorption to sludge and to the wastewater organic matter was responsible for a significant percentage of drugs removal. Nevertheless, these removal rates still result in considerable concentrations in the aqueous phase that will pass through the WWTP to the receiving environment. Measuring only the dissolved fraction of pharmaceuticals in the WWTP effluents may underestimate the loading and risks to the aquatic environment.

  2. Potential impacts of using sewage sludge biochar on the growth of plant forest seedlings

    Directory of Open Access Journals (Sweden)

    Maria Isidoria Silva

    Full Text Available ABSTRACT: Sewage sludge has long been successfully used in the production of nursery plants; however, some restriction may apply due to its high pathogenic characteristics. The process of charring the organic waste significantly reduces that undesired component and may be as effective as the non-charred residue. The aim of this study was to evaluate the effect of sewage sludge biochar on the growth and morphological traits of eucalyptus ( Eucalyptus grandis L. seedlings, and compare results with those observed when using uncharred sewage sludge. Treatments were arranged in a completely randomized design, in a 2 x 2 factorial scheme, with four replications. Charred and non-charred sewage sludge were tested with and without NPK addition. A control treatment was also evaluated. Ten weeks old eucalyptus seedlings were transferred to the pots and grew for eight weeks. Chlorophyll content, plant height and stem diameter were measured at 0, 30 and 60 days after transplant. Shoot and root biomass were measured after plant harvest. Dickson Quality Index was calculated to evaluate the overall quality of seedlings. Biochar was effective in improving the seedlings quality, and had similar effects as the non-charred waste. Therefore, sewage sludge biochar has the potential to improve the process of production of forest species seedlings and further reduce the environmental risks associated with the use of non-charred sewage sludge.

  3. Thermal activation of an industrial sludge for a possible valorization

    Directory of Open Access Journals (Sweden)

    Lamrani Sanae


    Full Text Available This work fits within the framework of sustainable management of sludge generated from wastewater treatment in industrial network. The studied sludge comes from an industry manufacturing sanitary ware products.Physico-chemical and mineralogical characterization was performed to give an identity card to the sludge. We noted the absence of metal pollution.The industrial sludge has been subjected to thermal activation at various temperatures (650°C to 850°C. The pozzolanic activity was evaluated by physico- chemical and mechanical methods [1]. Pozzolanicity measurement was carried out based on Chapelle test and conductivity revealed the existence of pozzolanic properties of the calcined samples. The best pozzolanic reactivity was obtained for the sample calcined at 800°C. We noticed a decrease in the reactivity of the sample calcined at 850°C. In addition, analysis by means of X-ray diffraction and Fourier transform infrared spectroscopy showed that sludge recrystallization begins at a temperature of 850°C. Pozzolanicity index of the thermally treated samples was determined by measuring the mechanical resistance of mortar specimens previously kept in a saturated lime solution for 28 days (ASTM C618 [2]. The best pozzolanic activity index was obtained for the sample calcined at 800°C (109.1%.This work is a contribution to the research for new supplying sources of raw materials and additives in the field of construction. It presents a proposition of a promising solution for the valorization of waste material as an additive instead of being discharged into open air dumps causing a major environmental problem.

  4. Influence of magnetic field on activity of given anaerobic sludge. (United States)

    Xu, Y B; Duan, X J; Yan, J N; Du, Y Y; Sun, S Y


    Two modes of magnetic fields were applied in the Cr(6+) removal sludge reactors containing two predominated strains--Bacillus sp. and Brevibacillus sp., respectively. The magnetic field mode I* of 0-4.5 or 0-14 mT between pieces was obtained by setting the magnetic pieces with the surface magnetic density of 0-6 or 0-20 mT into the reactor, and the magnetic field mode II* of 6, 20, or 40 mT on the return line was obtained by controlling the working distance of the permanent magnet outside the sludge return line. The effects of different magnetic fields on the activity of the given anaerobic sludge were studied by comparing with the control (absent of magnetic field). The results showed that the magnetic field of 0-4 mT improved the activity of given sludge most effectively, U(max) CH(4) (the peak methane-producing rate) and the methane producing volume per gCOD(Cr) reached 64.3 mlCH(4)/gVSS.d and 124 mlCH(4)/gCOD(Cr), which increased by 20.6 and 70.7%, respectively, compared with the control. And the magnetic field of 20 mT took second place. It could be concluded that the input of some magnetic field could improve the activity of anaerobic sludge by increasing the transformation efficiency of COD(Cr) matters to methane, and the total organic wastage did not increase.

  5. Evaluation-of soil enzyme activities as soil quality indicators in sludge-amended soils. (United States)

    Dindar, Efsun; Şağban, Fatma Olcay Topaç; Başkaya, Hüseyin Savaş


    Soil enzymatic activities are commonly used as biomarkers of soil quality. Several organic and inorganic compounds found in municipal wastewater sludges can possibly be used as fertilizers. Monitoring and evaluating the quality of sludge amended soils with enzyme activities accepted as a beneficial practice with respect to sustainable soil management. In the present study, variation of some enzyme activities (Alkaline phosphatase, dehydrogenase, urease and beta-glucosidase activities) in soils amended with municipal wastewater sludge at different application rates (50, 100 and 200 t ha(-1) dry sludge) was evaluated. Air dried sludge samples were applied to soil pots and sludge-soil mixtures were incubated during a period of three months at 28 degrees C. The results of the study showed that municipal wastewater sludge amendment apparently increased urease, dehydrogenase, alkaline phosphatase and P-glucosidase activities in soil by 48-70%, 14-47%, 33-66% and 9-14%, respectively. The maximum activity was generally observed in sludge amended soil with dose of 200 t ha(-1). Urease activity appeared to be a better indicator of soil enhancement with wastewater sludge, as its activity was more strongly increased by sludge amendment. Accordingly, urease activity is suggested to be soil quality indicator best suited for measuring existing conditions and potential changes in sludge-amended soil.


    Directory of Open Access Journals (Sweden)

    Stanisław Ledakowicz


    Full Text Available The most wastewater treatment plants in Poland are small and medium plants of flow capacity below 1000 m3/d. These plants are not able to build sludge incineration plants and the transportation costs to the nearest plants increase the total costs of wastewater treatment. Polish company Metal Expert together with the French company ETIA and Lodz University of Technology proposed mobile unit for integrated drying and pyrolysis of sewage sludge in a pilot bench scale with capacity of 100 kg/h of dewatered sludge. The pilot plant was mounted in a typical mobile container which could provide service to small and medium wastewater treatment plants offering thermal processing of sewage sludge. This unit consists of KENKI contact dryer and „Spirajoule”® pyrolyser supplied with electricity utilizing the Joule effect, and a boiler, wherein the pyrolysis gases and volatile products are burned producing steam sent to the contact dryer. The bio-char produced during sludge pyrolysis could be utilized for agriculture purposes. During preliminary experiments and short-term exploitation of the unit at Elbląg Wastewater Treatment Plant the obtained results allowed us to make a mass and energy balance depended on the process conditions in the pyrolysis temperature range of 400÷800 °C. Based on the obtained results a calculator was created in the Excel , which enables assessment of pyrolysis products content and making mass and energy balances depended on process parameters such as initial moisture of sludge, pyrolysis temperature and installation output.

  7. Substrate utilization and VSS relations in activated sludge processes

    Energy Technology Data Exchange (ETDEWEB)

    Droste, R.L.; Fernandes, L.; Sun, X. [Ottawa Univ., ON (Canada). Dept. of Civil Engineering


    A new empirical substrate removal model for activated sludge in continuous flow stirred tank reactor (CFSTR) and sequencing batch reactor (SBR) was developed in this study. This model includes an exponential function of volatile suspended solids to express the active biomass which is actually involved in substrate utilization. Results indicate that the proposed exponential models predict more accurately effluent COD in CFSTR and SBR systems than the first or zero order models. (author). 7 refs., 1 fig., 4 tabs.

  8. MiDAS Field Guide – a Comprehensive Online Source of Information About the Microbes of Activated Sludge

    DEFF Research Database (Denmark)

    Nierychlo, Marta; McIlroy, Simon Jon; Saunders, Aaron Marc

    activated sludge wastewater treatment systems, linking their identity with available information on their function and distribution. The guide includes the approx. 100 abundant genera that are present in most treatment plants (based on a survey of 25 full-scale Danish wastewater treatment plants...... that would be otherwise excluded from analyses. The MiDAS database importantly provides a common taxonomy for the field that gives a solid foundation for the study of microbial ecology of the activated sludge process and related wastewater treatment processes, such as biofilms and granular sludge. Each genus...... are provided. The MiDAS Field Guide is a continuously developing resource where all working in the field are invited to contribute....

  9. Relationship between protozoan and metazoan communities and operation and performance parameters in a textile sewage activated sludge system. (United States)

    Araújo dos Santos, Liliana; Ferreira, Vânia; Pereira, Maria Olívia; Nicolau, Ana


    The present study aims at investigating the possibility of assessing performance and depuration conditions of an activated sludge wastewater treatment plant through an exploration of the microfauna. The plant, receiving textile industrial (70%) and domestic (30%) sewage, consists of a two-step biological depurating plant, with activated sludge followed by a percolating system. A total of 35 samples were analyzed during five months, and 30 taxa of protozoa and small metazoa were found. Epistylis rotans, Vorticella microstoma, Aspidisca cicada and Arcella sp. were the most frequent protozoa identified. Several significant correlations between biological, physical-chemical and operational parameters were determined, but no significant correlations could be established between biological parameters and removal efficiencies. The Sludge Biotic Index (SBI) reflected the overall state of the community but only presented statistically significant correlations with the influent total suspended solids (TSS), total suspended solids in mixed-liquor (MLTSS) and dissolved oxygen (DO). The determination of key groups and taxa along with general community parameters showed to have potential value as indicators of the depuration conditions. Despite the impossibility of correlating biological parameters and the removal efficiencies, the present study attests the value of the microfauna to assess the operation of the activated sludge systems even in the case of non-conventional plants and/or plants receiving industrial sewage.

  10. Enhanced Lipid and Biodiesel Production from Glucose-Fed Activated Sludge: Kinetics an Microbial Community Analysis (United States)

    An innovative approach to increase biofuel feedstock lipid yields from municipal sewage sludge via manipulation of carbon:nitrogen (C:N) ratio and glucose loading in activated sludge bioreactors was investigated. Sludge lipid and fatty acid methyl ester (biodiesel) yields (% cel...

  11. Characterization of the fate of lipids in activated sludge

    Institute of Scientific and Technical Information of China (English)

    Kangala B.Chipasa; Krystyna Medrzycka


    Experiments were carried out to characterize the transformation of lipids in activated sludge under aerobic conditions. Results showed that the overall lipid content in the effluent could not be reduced to values below 300 mg/L from an initial content of 2, 000 mg/L. However, the contents of individual fatty acids underwent drastic decreases and increases during all microbial growth phases. These changes in contents of individual fatty acids showed that fatty acids were used as substrates by microorganisms as well as released into the wastewater as by-products. We have therefore suggested a novel model of transformation of lipids in activated sludge, showing that utilization of microbial activity for complete removal of lipids from wastewater is limited.

  12. Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants? (United States)

    Cristale, Joyce; Ramos, Dayana D; Dantas, Renato F; Machulek Junior, Amilcar; Lacorte, Silvia; Sans, Carme; Esplugas, Santiago


    This study aims to determine the occurrence of 10 OPFRs (including chlorinated, nonchlorinated alkyl and aryl compounds) in influent, effluent wastewaters and partitioning into sludge of 5 wastewater treatment plants (WWTP) in Catalonia (Spain). All target OPFRs were detected in the WWTPs influents, and the total concentration ranged from 3.67 µg L(-1) to 150 µg L(-1). During activated sludge treatment, most OPFRs were accumulated in the sludge at concentrations from 35.3 to 9980 ng g(-1) dw. Chlorinated compounds tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2,3-dichloropropyl) phosphate (TDCPP) were not removed by the conventional activated sludge treatment and they were released by the effluents at approximately the same inlet concentration. On the contrary, aryl compounds tris(methylphenyl) phosphate (TMPP) and 2-ethylhexyl diphenyl phosphate (EHDP) together with alkyl tris(2-ethylhexyl) phosphate (TEHP) were not detected in any of the effluents. Advanced oxidation processes (UV/H2O2 and O3) were applied to investigate the degradability of recalcitrant OPFRs in WWTP effluents. Those detected in the effluent sample (TCEP, TCIPP, TDCPP, tributyl phosphate (TNBP), tri-iso-butyl phosphate (TIBP) and tris(2-butoxyethyl) phosphate (TBOEP)) had very low direct UV-C photolysis rates. TBOEP, TNBP and TIBP were degraded by UV/H2O2 and O3. Chlorinated compounds TCEP, TDCPP and TCIPP were the most recalcitrant OPFR to the advanced oxidation processes applied. The study provides information on the partitioning and degradability pathways of OPFR within conventional activated sludge WWTPs.

  13. Impact of membrane solid-liquid separation on design of biological nutrient removal activated sludge systems. (United States)

    Ramphao, M; Wentzel, M C; Merritt, R; Ekama, G A; Young, T; Buckley, C A


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

  14. Microbiology of the active sludge as a system to improve the effluents quality in the wastewater treatment plants; La microbiologia del fango activo como sistema para mejorar la calidad de los efluentes en las depuradoras de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, E.; Reina, E.; Fernandez, N.


    Grupo Bioindicacion Sevilla (GBS) is a Spanish group of professionals interested in microbiology. GBS celebrates an annual activity about transfer of technology on microbiology of the active sludge, which fifth edition was celebrated in 2008 with the participation of different universities (Complutense de Madrid, Politecnica de Valencia y Barcelona, etc.) and public and private water companies (DAM, Aguas de Valencia, Aqualia, Emasesa, Emacsa...), and will celebrate again in Seville the next October. During this conference, the GBS group informs about the inter-laboratories exercises too, which last results are showed in this article. (Author) 9 refs.

  15. Limitation of sludge biotic index application for control of a wastewater treatment plant working with shock organic and ammonium loadings. (United States)

    Drzewicki, Adam; Kulikowska, Dorota


    This study aimed to determine the relationship between activated sludge microfauna, the sludge biotic index (SBI) and the effluent quality of a full-scale municipal wastewater treatment plant (WWTP) working with shock organic and ammonium loadings caused by periodic wastewater delivery from septic tanks. Irrespective of high/low effluent quality in terms of COD, BOD5, ammonium and suspended solids, high SBI values (8-10), which correspond to the first quality class of sludge, were observed. High SBI values were connected with abundant taxonomic composition and the domination of crawling ciliates with shelled amoebae and attached ciliates. High SBI values, even at a low effluent quality, limit the usefulness of the index for monitoring the status of an activated sludge system and the effluent quality in municipal WWTP-treated wastewater from septic tanks. It was shown that a more sensitive indicator of effluent quality was a change in the abundance of attached ciliates with a narrow peristome (Vorticella infusionum and Opercularia coarctata), small flagellates and crawling ciliates (Acineria uncinata) feeding on flagellates.

  16. Influence of flocculation and settling properties of activated sludge in relation to secondary settler performance. (United States)

    Wilén, B M; Onuki, M; Hermansson, M; Lumley, D; Mino, T


    Floc characteristics were studied at a full scale activated sludge treatment plant with a unique process solution incorporating pre-denitrification with post-nitrification in nitrifying trickling filters. Since greater nitrogen removal is achieved when more secondary settled wastewater is recirculated to the trickling filters, the secondary settlers are always operated close to their maximal capacity. The flocculation and settling properties are therefore crucial and have an effect on the overall plant performance. Since the plant is operated at a short sludge age, these properties change quickly, resulting in variable maximal secondary settler capacity. The dynamics in floc structure and microbial community composition were studied and correlated to the secondary settler performance. Fluorescence in situ hybridisation was used to investigate the microbial community structure and their spatial distribution. The floc structure could to some extent be related to the flocculation and settling properties of the sludge. Even small differences had an influence suggesting that colloidal properties also play a significant role in determining the floc properties. No correlation between microbial community composition and settling properties could be established with the group-specific probes investigated.

  17. Activated sludge models ASM1, ASM2, ASM2d and ASM3

    DEFF Research Database (Denmark)

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

    This book has been produced to give a total overview of the Activated Sludge Model (ASM) family at the start of 2000 and to give the reader easy access to the different models in their original versions. It thus presents ASM1, ASM2, ASM2d and ASM3 together for the first time.Modelling of activated...... sludge processes has become a common part of the design and operation of wastewater treatment plants. Today models are being used in design, control, teaching and research.ContentsASM3: Introduction, Comparison of ASM1 and ASM3, ASM3: Definition of compounds in the model, ASM3: Definition of processes...... in the Model, ASM3: Stoichiometry, ASM3: Kinetics, Limitations of ASM3, Aspects of application of ASM3, ASM3C: A Carbon based model, Conclusion ASM 2d: Introduction, Conceptual Approach, ASM 2d, Typical Wastewater Characteristics and Kinetic and Stoichiometric Constants, Limitations, Conclusion ASM 2...

  18. Application of BP NN and RBF NN in Modeling Activated Sludge System

    Institute of Scientific and Technical Information of China (English)

    王维斌; 郑丕谔; 李金勇


    Based on the operation data from a certain wastewater treatment plant(WWTP) in northeast China, the models of back propagation neural network(BP NN) and radial basis function neural network(RBF NN) have been designed respectively and the ability of convergence and generalization has been analyzed separately. As for BP NN, the effects of numbers of layers and nodes have been studied; as for RBF NN, the influences of the number of nodes and the RBF′s width have been studied. It is concluded that BP NN has converged much slowly in comparison with RBF NN. The conclusion that the RBF NN is suitable for modeling activated sludge system has been drawn. An automatically optimum design program for RBF NN has been developed, through which the RBF NN model of traditional activated sludge system has been established.

  19. Electrochemical pretreatment of waste activated sludge: effect of process conditions on sludge disintegration degree and methane production. (United States)

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


    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.

  20. The fate of linear alcohol ethoxylates during activated sludge sewage treatment. (United States)

    Battersby, N S; Sherren, A J; Bumpus, R N; Eagle, R; Molade, I K


    Model continuous activated sludge (CAS) plants (Husmann units) were used to study the fate of two commercial, alcohol ethoxylate (AE) surfactants during aerobic sewage treatment. The surfactants were produced by the ethoxylation of an essentially linear C(12-15) alcohol (NEODOL 25) with an average of 7 (C(12-15)EO7) or 3 (C(12-15)EO3) moles of ethylene oxide (EO). Recent analytical developments made it possible to measure levels of AE that included the free alcohol and EO1 oligomers across the CAS system, from the influent feed, on the activated sludge, through to the effluent. Measured concentrations of AE (as C(12-15)EO(0-20)) in the synthetic sewage feeds to the test CAS plants lay in the range 11-13 mg/l. During stable operation at 20 degrees C, an average of 5 microg/l AE were present in the C(12-15)EO7 CAS plant effluent, giving a removal (bioelimination) of >99.9%. When levels of AE on the sludge, and polyethylene glycols (PEGs--an expected biodegradation intermediate) in the effluent and on the sludge were also taken into account, biodegradation was considered to be responsible for >98.7% of the observed removal. During operation at a winter temperature (10 degrees C), an average of 26 microg/l AE were present in the C(12-15)EO7 CAS plant effluent, giving a removal of 99.8%. Biodegradation was estimated to be responsible for >97.2% of the observed removal. During operation at 20 degrees C, an average of 7 microg/l AE were present in the C(12-15)EO3 CAS plant effluent, giving a removal of >99.9%. No analysis for PEG was performed in this case but the low level of AE on the sludge (0.2 mg/g dry solids) suggested that biodegradation was responsible for most of the observed removal. Neither surfactant had any adverse effect on the sewage treatment efficiencies of the CAS plants in terms of dissolved organic carbon (DOC) removal, nitrification or biomass levels.


    Directory of Open Access Journals (Sweden)

    Keeren Sundara Rajoo


    Full Text Available Increase in human population has resulted in an enormous growth in the volume of wastewater. The conventional methods of sewage sludge disposal, that is the by-product of wastewater treatment, are costly and not environment-friendly. An ideal way for sewage sludge management is by using it as a soil amendment in agricultural land due to sewage sludge’s high organic matter content. However, sewage sludge contains high levels of heavy metals that can be harmful to both plants and the environment. Hence, these metals need to be removed before the sewage sludge is to be used as a soil amendment. The objective of this study was to assess the potential of Aquilaria malaccensis to uptake and translocate heavy metals found in sewage sludge. A.malaccensis seedlings were planted on six different planting media: T0/Control (100% soil, T1 (80% soil and 20% sewage sludge, T2 (60% soil and 40% sewage sludge, T3 (40% soil and 60% sewage sludge, T4 (20% soil and 80% sewage sludge and T5 (100% sewage sludge for the duration of 16 weeks. The growth performance of height and basal diameter was measured using diameter tape and venier caliper every two weeks, respectively. The average dry weight biomass of A.malaccensis was measured using destructive sampling at 16 weeks after planting. Plant samples were collected after harvest and soil samples were collected before planting and after harvesting. Atomic Absorbtion Spectrophotometer (AAS was used to determine the concentration of heavy metals in the planting media and the plant parts (leaves, stem and roots. The highest growth of A.malaccensis was recorded for the T5 growth media. The highest concentration of Fe in the roots of the A.malaccensis plant was in the T5 growth media (2770.75 ppm. The highest accumulation of Zn (95.62 ppm was recorded in the roots of A.malaccensis in the T5 growth media, whereas the stem of the A.malaccensis in T5 recorded the highest Cd accumulation (3.75 ppm. The highest Pb uptake

  2. Metaproteomics: Evaluation of protein extraction from activated sludge. (United States)

    Hansen, Susan Hove; Stensballe, Allan; Nielsen, Per Halkjaer; Herbst, Florian-Alexander


    Metaproteomic studies of full-scale activated sludge systems require reproducible protein extraction methods. A systematic evaluation of three different extractions protocols, each in combination with three different methods of cell lysis, and a commercial kit were evaluated. Criteria used for comparison of each method included the extracted protein concentration and the number of identified proteins and peptides as well as their phylogenetic, cell localization and functional distribution and quantitative reproducibility. Furthermore, the advantage of using specific metagenomes and a 2-step database approach was illustrated. The results recommend a protocol for protein extraction from activated sludge based on the protein extraction reagent B-Per and bead beating. The data have been deposited to the ProteomeXchange with identifier PXD000862 (

  3. "The Effects of Temperature and PH on Settlability of Activated Sludge Flocs"

    Directory of Open Access Journals (Sweden)

    Gh Ghanizadeh


    Full Text Available The effluent quality of a sewage treatment plant using activated sludge process and finally secondary treatment depends on the flocculation efficiency and settling of the flocs. The survey of various treatment processes in water and wastewater treatment shows that temperature and pH are the important factors affecting efficiency of flocculation and settling properties. This study was performed to determine the effects of pH and temperature on settling of the flocs in activated sludge process. It was carried out for three months in two phases, using mixed liquor suspended solids (MLSS, obtained from aeration tank from one of wastewater treatment plants in Tehran. In the primary phase, the temperature of samples was increased from 15°C to 35°C. As a result, the sludge volume index (SVI and effluent suspended solids increased and consequently, COD removal percent decreased. In the second phase, the pH was increased from 5.7 to 9. As a result, SVI and effluent suspended solids decreased and COD removal percent increased.

  4. Activated sludge process based on artificial neural network

    Institute of Scientific and Technical Information of China (English)

    张文艺; 蔡建安


    Considering the difficulty of creating water quality model for activated sludge system, a typical BP artificial neural network model has been established to simulate the operation of a waste water treatment facilities. The comparison of prediction results with the on-spot measurements shows the model, the model is accurate and this model can also be used to realize intelligentized on-line control of the wastewater processing process.

  5. Wet oxidation of activated sludge: transformations and mechanisms. (United States)

    Urrea, José Luis; Collado, Sergio; Laca, Amanda; Díaz, Mario


    Wet oxidation (WO) is an interesting alternative for the solubilization and mineralization of activated sludge. The effects of different temperatures (160-200 °C) and pressures (4-8 MPa), on the evolution of chemical composition and rheological characteristics of a thickened activated sludge during WO are analyzed in this work. Soluble COD increases initially to a maximum and then diminishes, while the apparent viscosity of the mixture falls continuously throughout the experiment. Based on the experimental evolution of the compositions and rheological characteristics of the sludge, a mechanism consisting of two stages in series is proposed. Initially, the solid organic compounds are solubilized following a pseudo-second order kinetic model with respect to solid COD. After that, the solubilized COD was oxidized, showing a pseudofirst kinetic order, by two parallel pathways: the complete mineralization of the organic matter and the formation of highly refractory COD. Kinetic parameters of the model, including the activation energies are mentioned, with good global fitting to the experiments described.

  6. Preparation of activated carbon from wet sludge by electrochemical-NaClO activation. (United States)

    Miao, Chen; Ye, Caihong; Zhu, Tianxing; Lou, Ziyang; Yuan, Haiping; Zhu, Nanwen


    Activated carbon (AC) from sludge is one potential solution for sewage sludge disposal, while the drying sludge is cost and time consuming for preparation. AC preparation from the wet sludge with electrochemical-NaClO activation was studied in this work. Three pretreatment processes, i.e. chemical activation, electrolysis and electrochemical-reagent reaction, were introduced to improve the sludge-derived AC properties, and the optimum dosage of reagent was tested from the 0.1:1 to 1:1 (mass rate, reagent:dried sludge). It was shown that the electrochemical-NaClO preparation is the best method under the test conditions, in which AC has the maximum Brunauer, Emmett and Teller area of 436 m²/g at a mass ratio of 0.7. Extracellular polymeric substances in sludge can be disintegrated by electrochemical-NaClO pretreatment, with a disintegration degree of more than 45%. The percentage of carbon decreased from 34.16 to 8.81 after treated by electrochemical-NaClO activation. Fourier transform infrared spectra showed that a strong C-Cl stretching was formed in electrochemical-NaClO prepared AC. The maximum adsorption capacity of AC reaches 109 mg/g on MB adsorption experiment at pH 10 and can be repeated for three times with high removal efficiency after regeneration.

  7. Estimation of Viable Biomass In Wastewater And Activated Sludge By Determination of ATP, Oxygen Utilization Rate And FDA Hydrolysis

    DEFF Research Database (Denmark)

    Jørgensen, Poul-Erik; Eriksen, T.; Jensen, B.K.


    ATP content, oxygen utilization rate (OUR) and fluorescein diacetate (FDA) hydrolysis were tested for the ability to express the amount of viable biomass in wastewater and activated sludge. The relationship between biomass and these activity parameters was established in growth cultures made...... with biomass, while FDA hydrolysis in the sludge failed to show any such correlation. Conversion factors of 3 mg ATP/g dw, 300 mg O2/h g dw and 0.4 A/h (mg dw/ml) for ATP, OUR and FDA methods, respectively, were calculated. When the methods were applied for in situ determinations in four different wastewater...... plants, it was found that ATP content and respiration rate estimated viable biomass to range from 81 to 293 mg dw/g SS for raw wastewater and from 67 to 187 mg dw/g SS for activated sludge with a rather weak correlation between ATP and respiration measurements. The FDA hydrolysis estimated viable biomass...


    Directory of Open Access Journals (Sweden)

    Małgorzata Koncewicz-Baran


    Full Text Available A great variety of sewage sludge treatment methods, due to the agent (chemical, biological, thermal leads to the formation of varying ‘products’ properties, including the content of heavy metals forms. The aim of the study was to determine the effects of biologically and thermally transformed sewage sludge on the manganese content in plants and form of this element in the soil. The study was based on a two-year pot experiment. In this study was used stabilized sewage sludge collected from Wastewater Treatment Plant Krakow – ”Płaszów” and its mixtures with wheat straw in the gravimetric ratio 1:1 in conversion to material dry matter, transformed biologically (composting by 117 days in a bioreactor and thermally (in the furnace chamber with no air access by the following procedure exposed to temperatures of 130 °C for 40 min → 200 °C for 30 min. In both years of the study biologically and thermally transformed mixtures of sewage sludge with wheat straw demonstrated similar impact on the amount of biomass plants to the pig manure. Bigger amounts of manganese were assessed in oat biomass than in spring rape biomass. The applied sewage sludge and its biologically and thermally converted mixtures did not significantly affect manganese content in plant biomass in comparison with the farmyard manure. The applied fertilization did not modify the values of translocation and bioaccumulation ratios of manganese in the above-ground parts and roots of spring rape and oat. No increase in the content of the available to plants forms of manganese in the soil after applying biologically and thermally transformed sewage sludge mixtures with straw was detected. In the second year, lower contents of these manganese forms were noted in the soil of all objects compared with the first year of the experiment.

  9. Bioproducts for Sludge Reduction in Activated Sludge Systems Treating Oil Refinery Wastewater

    Directory of Open Access Journals (Sweden)

    Alexandre V.M.F.


    Full Text Available The use of bioproducts that change the cellular metabolism and reduce microbial growth without affecting the organic matter removal is very promising for reducing the amount of sludge in wastewater treatment systems. In this study, two bioproducts were evaluated and compared with a well-known chemical (2,4-DiNitroPhenol – DNP in activated sludge treating petroleum refinery wastewater. In batch experiments, 10 mg/L of DNP, 0.8 mg/L of a bioproduct based on Folic Acid (FA and 10 mg/L of a bioproduct based on Stress Proteins (SP led to 30.6%, 43.2% and 29.8% lower disposal of total solids, respectively. Operating on a continuous regimen, the addition of 10 mg/L of the bioproduct based on SP led to 45.7% lower disposal for 50 days. In all cases, no loss of efficiency in the Chemical Oxygen Demand (COD removal was observed.

  10. A comparison of BNR activated sludge systems with membrane and settling tank solid-liquid separation. (United States)

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


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

  11. Treatability Studies of Tributyltin in Activated Sludge (United States)


    vessels were incubated at 250C in the dark, enclosed in the temperature-controlled waterbath, and stirred continu- ously throughout the run. The microbiota ...stirred continuously throughout the run. The microbiota used for these runs were acclimated to 100 ug/L of TBT. Anaerobic Screening Using fast TBT will degrade in a municipal sewage treatment plant because kinetic studies requiring techniques other than electrolytic respirom- etry

  12. Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge. (United States)

    Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M


    The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

  13. Sludge settling processes in SBR-related sewage treatment plants according to the Biocos method. (United States)

    Meusel, S; Englert, R


    This paper describes the investigations in a sedimentation and circulation reactor (SU-reactor) of a three-phase Biocos plant. The aim of these investigations was the determination of the temporal and depth-dependent distribution of suspended solid contents, as well as describing the sludge sedimentation curves. The calculated results reveal peculiarities of the Biocos method with regard to sedimentation processes. In the hydraulically uninterrupted (pre-)settling phase, a sludge level depth was observed, which remained constant over the reactor surface and increased linearly according to the sludge volume. The settling and the thickening processes of this phase corresponded to a large extent to the well-known settling test in a one-litre measuring cylinder. During the discharge phase, the investigated settling rate was overlaid by the surface loading rate and the sludge level changed depending on the difference between those two parameters. The solid distribution of the A-phase indicated a formation of functional zones, which were influenced by the surface loading. The formation was comparable to the formation of layers in secondary settling tanks with vertical flow. The concentration equalisation between the biological reactor and the SU-reactor proved to be problematic during the circulation phase, because a type of internal sludge circulation occurred in the SU-reactor. A permanent sludge recirculation seems to be highly recommendable.

  14. PBDEs versus NBFR in wastewater treatment plants: occurrence and partitioning in water and sludge

    Directory of Open Access Journals (Sweden)

    Joyce Cristale


    Full Text Available This study evaluates the occurrence of flame retardants (FR in five wastewater treatment plants (WWTPs located close to Barcelona (NE Spain, an area with high urban and industrial pressures. Compounds studied include eight polybromodiphenyl ethers (PBDEs and eight New Brominated Flame Retardants (NBFRs, for which little information regarding their presence, partitioning and fate within the WWTPs is available. In unfiltered influent samples, PBDEs were not detected and bis(2-ethyl-1-hexyltetrabromophthalate was the only NBFR detected, and all WWTPs were efficient in eliminating this compound as no residues were found in the effluents. However, primary sludge contained from 279 to 2299 ng/g dry weight of ΣFR and the concentration increased in secondary (biological sludge. NBFRs accounted for the main FR detected in sludge, representing a 63-97% of the total load, and among PBDEs, BDE-209 was the most ubiquitous congener. Considering the amount of sludge generated in each WWTP, it was estimated that 0.34-17.2 kg of FR are released annually through the sludge, which can have negative environmental and health implications if sludge is used as biosolid in agriculture. Overall, this study provides a sampling design and analytical protocol to be used to determine the evolution of FR in WWTPs and compares the levels detected, considering that PBDEs are being phased out to be substituted by other compounds which also have high accumulative and recalcitrant properties.

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

    Directory of Open Access Journals (Sweden)

    Gouveia R.


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

  16. Presence of Naturally Occurring Radioactive Materials in sludge samples from several Spanish water treatment plants

    Energy Technology Data Exchange (ETDEWEB)

    Palomo, M.; Penalver, A.; Aguilar, C. [Unitat de Radioquimica Ambiental i Sanitaria, Universitat Rovira i Virgili, Consorci d' Aigues de Tarragona (CAT), Ctra. Nacional 340 Km. 1094, Ap. correus n.7, 43895 L' Ampolla, Tarragona (Spain); Borrull, F., E-mail: [Unitat de Radioquimica Ambiental i Sanitaria, Universitat Rovira i Virgili, Consorci d' Aigues de Tarragona (CAT), Ctra. Nacional 340 Km. 1094, Ap. correus n.7, 43895 L' Ampolla, Tarragona (Spain)


    Sludge samples from eleven potable water treatment plants (PWTP), three waste water treatment plants (WWTP) and an industrial water treatment plant (IWTP), located in different areas of Spain, mainly in Catalonia, were analyzed for their radiological content in order to determine whether they could be considered as industries affected by naturally occurring radioactive material (NORM). In general, samples from the PWTPs showed higher activity values for the alpha and gamma emitting isotopes than the WWTPs and the IWTP. For example, samples from the area located in the north of Catalonia show values of {sup 234}U, {sup 235}U and {sup 238}U in the range of 84.4-792.1 Bq/kg, 3.3-26.8 Bq/kg and 63.8-585.9 Bq/kg, respectively. In general, for PWTP, the values obtained for the gamma emitter and alpha emitter isotopes showed that both the geology and the industrial activities correlate with the values measured. The magnitude of these results demonstrates the need to measure the radionuclide content of these samples before reaching a decision about their final disposal.

  17. Evaluation of aeration energy saving in two modified activated sludge processes. (United States)

    Lee, Ingyu; Lim, Honglae; Jung, Byunghun; Colosimo, Mark F; Kim, Hyunook


    A variety of modified activated sludge processes are widely used in wastewater treatment plants (WWTPs) for removing organics and nutrients (N and P). Since energy consumption in aeration basin accounts for the major part of the overall energy usage in WWTPs, efforts have been made to find ways to reduce aeration energy. In this study, two modified activated sludge processes in a pilot scale designed for nutrient removal were evaluated for the extent of energy saving: (1) ABA(2) process - adjusting air on/off period (i.e., with a temporal change); and (2) MB-A(2)O process - changing volume ratio of aerobic tank to anoxic tank (i.e., with a spatial change). For the 1st process, the air on/off period was fixed at 60min/45min with aerobic fraction being 0.57, while for the 2nd process, the aerobic/anoxic volume ratio was reduced from 0.58 to 0.42. The results demonstrate that the effluent COD, TN, NH4(+) and TP concentrations are acceptable while reduced aeration time/volume certainly saves significant energy consumption. To the best of our knowledge, this is 1st attempt to reduce the aeration period or aeration volume to save the aeration energy in these two modified activated sludge processes. The implication of these observations is further discussed.

  18. Comparison of heavy metal removal efficiencies in four activated sludge processes

    Institute of Scientific and Technical Information of China (English)

    杨军; 高定; 陈同斌; 雷梅; 郑国砥; 周小勇


    The removal efficiencies of heavy metals (As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants (WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As (75.5%) in the oxidation ditch (OD) process is significantly higher than that in the conventional activated sludge (CAS) process (38.6%) or sequencing batch reactor (SBR) process (51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu (69.9%) and Ni (16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic (A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.

  19. Treatment of biomass gasification wastewater using a combined wet air oxidation/activated sludge process

    Energy Technology Data Exchange (ETDEWEB)

    English, C.J.; Petty, S.E.; Sklarew, D.S.


    A lab-scale treatability study for using thermal and biological oxidation to treat a biomass gasification wastewater (BGW) having a chemical oxygen demand (COD) of 46,000 mg/l is described. Wet air oxidation (WA0) at 300/sup 0/C and 13.8 MPa (2000 psi) was used to initially treat the BGW and resulted in a COD reduction of 74%. This was followed by conventional activated sludge treatment using operating conditions typical of municipal sewage treatment plants. This resulted in an additional 95% COD removal. Overall COD reduction for the combined process was 99%. A detailed chemical analysis of the raw BGW and thermal and biological effluents was performed using gas chromatography/mass spectrometry (GC/MS). These results showed a 97% decrease in total extractable organics with WA0 and a 99.6% decrease for combined WA0 and activated sludge treatment. Components of the treated waters tended to be fewer in number and more highly oxidized. An experiment was conducted to determine the amount of COD reduction caused by volatilization during biological treatment. Unfortunately, this did not yield conclusive results. Treatment of BGW using WA0 followed by activated sludge appears to be very effective and investigations at a larger scale are recommended.

  20. Biofilms Versus Activated Sludge: Considerations in Metal and Metal Oxide Nanoparticle Removal from Wastewater. (United States)

    Walden, Connie; Zhang, Wen


    The increasing application of metal and metal oxide nanoparticles [Me(O)NPs] in consumer products has led to a growth in concentration of these nanoparticles in wastewater as emerging contaminants. This may pose a threat to ecological communities (e.g., biological nutrient removal units) within treatment plants and those subject to wastewater effluents. Here, the toxicity, fate, and process implications of Me(O)NPs within wastewater treatment, specifically during activated sludge processing and biofilm systems are reviewed and compared. Research showed activated sludge achieves high removal rate of Me(O)NPs by the formation of aggregates through adsorption. However, recent literature reveals evidence that inhibition is likely for nutrient removal capabilities such as nitrification. Biofilm systems were much less studied, but show potential to resist Me(O)NP inhibition and achieve removal through possible retention by sorption. Implicating factors during bacteria-Me(O)NP interactions such as aggregation, surface functionalization, and the presence of organics are summarized. At current modeled levels, neither activated sludge nor biofilm systems can achieve complete removal of Me(O)NPs, thus allowing for long-term environmental exposure of diverse biological communities to Me(O)NPs in streams receiving wastewater effluents. Future research directions are identified throughout in order to minimize the impact of these nanoparticles released.

  1. Self-heating co-pyrolysis of excessive activated sludge with waste biomass: energy balance and sludge reduction. (United States)

    Ding, Hong-Sheng; Jiang, Hong


    In this work, co-pyrolysis of sludge with sawdust or rice husk was investigated. The results showed that the co-pyrolysis technology could be used to dispose of the excessive activated sludge without external energy input. The results also demonstrated that no obvious synergistic effect occurred except for heat transfer in the co-pyrolysis if the co-feeding biomass and sludge had similar thermogravimetric characteristics. The experimental results combined with calculation showed that adding sawdust accounting for 49.6% of the total feedstock or rice husk accounting for 74.7% could produce bio-oil to keep the energy balance of the co-pyrolysis system and self-heat it. The sludge from solar drying bed can be further reduced by 38.6% and 35.1% by weight when co-pyrolyzed with rice husk and sawdust, respectively. This study indicates that sludge reduction without external heat supply through co-pyrolysis of sludge with waste biomass is practically feasible.

  2. Genomic and in situ investigations of the novel uncultured Chloroflexi associated with 0092 morphotype filamentous bulking in activated sludge. (United States)

    McIlroy, Simon Jon; Karst, Søren Michael; Nierychlo, Marta; Dueholm, Morten Simonsen; Albertsen, Mads; Kirkegaard, Rasmus Hansen; Seviour, Robert James; Nielsen, Per Halkjær


    Overgrowth of filamentous bacteria in activated sludge wastewater treatment plants (WWTPs) leads to impaired sludge settleability, a condition known as bulking, which is a common operational problem worldwide. Filaments with the Eikelboom 0092 morphotype are commonly associated with such bulking episodes. Members of the uncultured B45 phylotype, which is embraced within the phylum Chloroflexi, were recently shown to exhibit this morphology. Although these organisms are among the most abundant populations recorded in activated sludge processes, nothing is known about their metabolic characteristics. In this study, a genome sequence, representing the B45 phylotype, was retrieved from a metagenome generated from an activated sludge WWTP. The genome consisted of two chromosomes and one plasmid, which were 4.0, 1.0 and 0.04 Mbps in size, respectively. A metabolic model was constructed for this organism, based on annotation of its genome, showing its ability to generate energy by respiration, utilizing oxygen, nitrite or nitrous oxide as electron acceptors, or by fermentation of sugars. The ability of B45 members to ferment sugars under anaerobic conditions was validated in situ with microautoradiography-fluorescence in situ hybridization. The provisional name of 'Candidatus Promineofilum breve' is proposed for this species. This study represents the first detailed information on an uncultured genus of filamentous organisms from activated sludge.

  3. Composting plant of vegetables wastes and sewage sludges in Castesdefells. Plant de compostaje de restos de poda y lodos de depuradora en Castelldefells

    Energy Technology Data Exchange (ETDEWEB)


    Castelldefells Municipality (Catalonia, Spain) has set up a recycling plant for vegetable wastes mixed with sewage sludge to obtain compost. The plant treats 48.000 m''3/y. of vegetable wastes, and receive 8.000 m''3/y. of sewage sludge. (Author)

  4. First discovery of acetone extract from cottonseed oil sludge as a novel antiviral agent against plant viruses. (United States)

    Zhao, Lei; Feng, Chaohong; Hou, Caiting; Hu, Lingyun; Wang, Qiaochun; Wu, Yunfeng


    A novel acetone extract from cottonseed oil sludge was firstly discovered against plant viruses including Tobacco mosaic virus (TMV), Rice stripe virus (RSV) and Southern rice black streaked dwarf virus (SRBSDV). Gossypol and β-sitosterol separated from the acetone extract were tested for their effects on anti-TMV and analysed by nuclear magnetic resonance (NMR) assay. In vivo and field trials in different geographic distributions and different host varieties declared that this extract mixture was more efficient than the commercial agent Ningnanmycin with a broad spectrum of anti-plant-viruses activity. No phytotoxic activity was observed in the treated plants and environmental toxicology showed that this new acetone extract was environmentally friendly, indicating that this acetone extract has potential application in the control of plant virus in the future.

  5. Activated sewage sludge, a potential animal foodstuff. Part I. Nutritional characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Tacon, A.G.J.


    The nutritive value of activated sewage sludge is discussed in terms of its amino acid N, non-amino acid N, carbohydrate, fat, mineral, vitamin and microbial content. Processed activated sewage sludge is described as a stable dark brown material of relatively uniform quality, having a nutritive value broadly equivalent to brewers yeast or a protein-rich cereal. The potential hazards associated with the use of activated sewage sludge as a feed ingredient are discussed. 29 references

  6. [Characterisation of excess sludge reduction in an anoxic + oxic-settling-anaerobic activated sludge process]. (United States)

    Gao, Xu; Lu, Yan-Hua; Guo, Jin-Song


    An energy balance analysis method with auto calorimeter being adopted was introduced to determine calorific values of sludge samples in influent and effluent of uncoupling tank in an anoxic (A) + oxic-settling-anaerobic (OSA) process and a reference system. The affiliation of sludge amount change and its energy content were studied, as well as potential of excess sludge reduction was evaluated through modifying performance of uncoupling tank. The characteristi s and causes of sludge reduction in OSA system were deduced according to energy and matter balance analysis. Results show that when the hydraulic retention time (HRT) of uncoupling tank are 5.56 h, 7.14 h and 9 h, the excess sludge reduction of whole A + OS Asystem are 1.236 g/d, 0.771 g/d and 0.599 g/d respectively. Energy content of sludge flows into and out of the uncoupling tank changes, the specific calorific value of sludge in effluent is inclined to be higher than that in influent with the HRT of the tank increasing: there isn't any significant difference of sludge calorific values between influent and effluent at 5.56 h, while the differences are in 99-113 J/g at 7.14 h, and 191-329 J/g at 9 h. Sludge in uncoupling tank would decay and longer HRT will result in more attenuation. It could be concluded that excess sludge reduction of A + OSA system is caused by both of sludge decay in uncoupling tank and sludge proliferation in AO reaction zone.

  7. Steady-state analysis of activated sludge processes with a settler model including sludge compression. (United States)

    Diehl, S; Zambrano, J; Carlsson, B


    A reduced model of a completely stirred-tank bioreactor coupled to a settling tank with recycle is analyzed in its steady states. In the reactor, the concentrations of one dominant particulate biomass and one soluble substrate component are modelled. While the biomass decay rate is assumed to be constant, growth kinetics can depend on both substrate and biomass concentrations, and optionally model substrate inhibition. Compressive and hindered settling phenomena are included using the Bürger-Diehl settler model, which consists of a partial differential equation. Steady-state solutions of this partial differential equation are obtained from an ordinary differential equation, making steady-state analysis of the entire plant difficult. A key result showing that the ordinary differential equation can be replaced with an approximate algebraic equation simplifies model analysis. This algebraic equation takes the location of the sludge-blanket during normal operation into account, allowing for the limiting flux capacity caused by compressive settling to easily be included in the steady-state mass balance equations for the entire plant system. This novel approach grants the possibility of more realistic solutions than other previously published reduced models, comprised of yet simpler settler assumptions. The steady-state concentrations, solids residence time, and the wastage flow ratio are functions of the recycle ratio. Solutions are shown for various growth kinetics; with different values of biomass decay rate, influent volumetric flow, and substrate concentration.

  8. Increasing the sludge energy potential of wastewater treatment plants by introducing fine mesh sieves for primary treatment. (United States)

    Paulsrud, Bjarne; Rusten, Bjørn; Aas, Bjørn


    The objective of this study was to compare some basic characteristics of sludge from fine mesh sieves (sieve sludge) with sludge from primary clarifiers (primary sludge) regarding their energy potential with a focus on anaerobic digestion and/or incineration. Nineteen samples of sludge from fine mesh sieve plants (most of them without fine screens and grit chambers as pre-treatment) and 10 samples of primary sludge were analysed for the content of dry solids (DS), volatile solids (VS), chemical oxygen demand (COD), calorific value and methane potential. The results demonstrated that the sieve sludges have significantly higher VS content and higher methane potential than primary sludges, clearly indicating an increased sludge energy potential if fine mesh sieves are used for primary treatment instead of primary clarifiers at wastewater treatment plants with anaerobic digesters. If the sludges from primary treatment are to be incinerated or used as fuel in cement kilns, there is no significant difference in energy potential (given as calorific values) for the two types of primary treatment.

  9. A Comprehensive Insight into Tetracycline Resistant Bacteria and Antibiotic Resistance Genes in Activated Sludge Using Next-Generation Sequencing

    Directory of Open Access Journals (Sweden)

    Kailong Huang


    Full Text Available In order to comprehensively investigate tetracycline resistance in activated sludge of sewage treatment plants, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential tetracycline resistant bacteria (TRB and antibiotic resistance genes (ARGs in sludge cultured with different concentrations of tetracycline. Pyrosequencing of 16S rRNA gene revealed that tetracycline treatment greatly affected the bacterial community structure of the sludge. Nine genera consisting of Sulfuritalea, Armatimonas, Prosthecobacter, Hyphomicrobium, Azonexus, Longilinea, Paracoccus, Novosphingobium and Rhodobacter were identified as potential TRB in the sludge. Results of qPCR, molecular cloning and metagenomic analysis consistently indicated that tetracycline treatment could increase both the abundance and diversity of the tet genes, but decreased the occurrence and diversity of non-tetracycline ARG, especially sulfonamide resistance gene sul2. Cluster analysis showed that tetracycline treatment at subinhibitory concentrations (5 mg/L was found to pose greater effects on the bacterial community composition, which may be responsible for the variations of the ARGs abundance. This study indicated that joint use of 454 pyrosequencing and Illumina high-throughput sequencing can be effectively used to explore ARB and ARGs in the environment, and future studies should include an in-depth investigation of the relationship between microbial community, ARGs and antibiotics in sewage treatment plant (STP sludge.

  10. The effect of electron acceptors on biogas production from tannery sludge of a Mexican wastewater plant (United States)

    Effluents from the leather processing plants generally are discharged into rivers or are used to irrigate farmland. The biogas production from the digestion of sludge produced could be used as alternative sources for energy and power generation. A study was carried out to examine the effects of vari...

  11. Effect of gamma-ray irradiation on the dewaterability of waste activated sludge (United States)

    Wu, Yuqi; Jiang, Yinghe; Ke, Guojun; Liu, Yingjiu


    The effect of gamma-ray irradiation on waste activated sludge (WAS) dewaterability was investigated with irradiation doses of 0-15 kGy. Time to filter (TTF50), specific resistance of filtration (SRF) and water content of sludge cake were measured to evaluate sludge dewaterability. Soluble chemical oxygen demand (SCOD), soluble extracellular polymeric substances (EPS) concentration and sludge particle size were determined to explain changes in sludge dewaterability. The optimal irradiation dose to obtain the maximum dewaterability characteristics was 1-4 kGy, which generated sludge with optimal disintegration (1.5-4.0%), soluble EPS concentration (590-750 mg/L) and particle size distribution (100-115 μm diameter). The combination of irradiation and cationic polyacrylamide (CPAM) addition exhibited minimal synergistic effect on increasing sludge dewatering rate compared with CPAM conditioning alone.

  12. Principles and potential of the anaerobic digestion of waste-activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Appels, Lise; Degreve, Jan [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. De Croylaan 46, B-3001 Heverlee (Belgium); Baeyens, Jan [Department of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Dewil, Raf [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. De Croylaan 46, B-3001 Heverlee (Belgium); Department of Chemical Engineering, Associated Faculty of Technology and Biosciences, Campus De Nayer, Katholieke Universiteit Leuven, Jan De Nayerlaan 5, B-2860 Sint-Katelijne-Waver (Belgium)


    When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into biogas (60-70 vol% of methane, CH{sub 4}), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of anaerobic digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include

  13. Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor. (United States)

    Ge, Huoqing; Batstone, Damien; Keller, Jurg


    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.

  14. Functions and behaviors of activated sludge extracellular polymeric substances (EPS): a promising environmental interest

    Institute of Scientific and Technical Information of China (English)

    TIAN Yu; ZHENG Lei; SUN De-zhi


    Extracellular polymeric substances (EPS) are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore,EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed.Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.


    Institute of Scientific and Technical Information of China (English)

    阮慧娟; 徐高田; 尚飞宵; 许莉


    The biological treatment of Zhuyuan No.2 WWTP is a new closed two-sludge treatment process.Activated Sludge Model No.l was used as a base for modelling of the activated sludge system.The component concentrations in wastewater、the heterotrophic yield coefficient(YH) and heterotrophic decay coefficient(bH) parameters of the activated sludge system had been measured in Zhuyuan NO.2 WWTP and these data provide the essential data for model establishment and model correction.The results showed that: the ratios of readily biodegradable substrate(Ss),slowly biodegradable substrate(Xs),soluble inert substrate(SI),heterotrophic biomass(XBH) and particulate inert substrate(XI) to total COD are 20.0%,32.1%,17.4%,9.6% and 20.9%,respectively.The ratios of ammonium(SNH),soluble biodegradable organic nitrogen(SND)、particulate biodegradable organic nitrogen(XND) to TN are 71.5%,10.0% and 18.5%,respectively.The heterotrophic yield coefficient(YH) of the traditional activated sludge process branch and the A/O process branch of the closed two-sludge treatment process are 0.68 and 0.78,respectively;heterotrophic decay coefficient(bH) is 0.501 d-1and 0.621 d-1,respectively.%竹园第二污水厂采用一种闭式双泥龄新型工艺。以活性污泥1号模型(ASM1)为基础,测定污水厂的进水水质特性参数、异养菌产率系数(YH)和异养菌衰减系数(bH),为后续工艺模型的建立和校正提供基础数据。结果表明:竹园第二污水厂进水易生物降解有机物(Ss)、慢速生物降解有机物(Xs)、溶解态惰性有机物(SI)、异养菌(XBH)、颗粒态惰性有机物(XI)占总COD的平均比值分别为20.0%、32.1%、17.4%、9.6%、20.9%。进水氨氮(SNH)、溶解态可生物降解有机氮(SND)、颗粒态可生物降解有机氮(XND)占TN的平均比值分别为71.5%、10.0%、18.5%。闭式双泥龄工艺平行组合中的传统活性污泥


    Directory of Open Access Journals (Sweden)

    Anna Iżewska


    Full Text Available Pomorzany Sewage Treatment Plant in Szczecin ensures the required parameters of treated sewage. However, due to higher efficiency of sewage treatment, more sludge is produced after the treatment process. In the examined sludge treatment plant, primary sludge is gravitationally thickened to the content of about 5% of dry matter, and the excessive is thickened in mechanical compactors up to 6% of dry matter. Settlements preliminary and excessive after compaction is discharged to the sludge tank where a pump is forced into two closed digesters. Each digester has the capacity of 5069 m3. At a temperature of about 37 °C a mesophilic digestion is performed. Biogas, that is produced in the chamber, is stored in two-coat tanks with the capacity of 1500 m3 each and after desulphurization with the biosulfex method (which results with obtaining elemental sulphur it is used as fuel in cogeneration units. The aim of this study was to determine amount of energy given by sewage sludge in the form of heat during the process of methane digestion (primary and excessive. These amounts were determined on the basis of chemical energy balance of sewage carried into and out of Separate Sludge Digesters and produced biogas within 24h. The study determined that the percentage value of average chemical energy amount turned into heat and discharged with produced methane in relation to chemical energy of sewage carried into the first digester in Pomorzany Treatment Plant in Szczecin was in the range of 47.86 ± 9.73% for a confidence level of 0.95. On average 80.86 ± 33.65% was emitted with methane and 19.14 ± 33.65% of energy was changed into heat.

  17. Effects Of Various Parameters On The Thickening Of Softening Plant Sludges

    DEFF Research Database (Denmark)

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


    photomicrographs indicated that only the calcium carbonate precipitate has a well-defined crystal structure. The shift of the crystal size distribution (CSD) to greater sizes, observed by comparing the different sludges, may be due to bigger calcite crystals rather than to crystal size changes caused......Spectroscopic and thermal data for sludges from full-scale softening plants showed calcium and magnesium precipitated as calcite and an amorphous hydrated hydroxide, respectively. Magnesium ions were not incorporated into the calcium lattice to form a magnesian calcite. Scanning electron...

  18. The activated sludge bulking filament Eikelboom morphotype 0914 is a member of the Chloroflexi. (United States)

    Speirs, Lachlan B M; McIlroy, Simon J; Petrovski, Steve; Seviour, Robert J


    The filamentous bacterium Eikelboom morphotype type 0914 responsible for bulking in activated sludge plants is identified here for the first time as a member of the phylum Chloroflexi subgroup 1. Two FISH probes, CFX67a and CFX67b, targeting the 16S rRNA sequences of this filament morphotype were designed, validated and used successfully for its in situ identification. A survey of plants in eastern Australia with the CFX67a probe showed it targeted only the type 0914 morphotype that was common especially in long sludge age plants designed to remove phosphorus and nitrogen microbiologically, although being in very low abundance in many samples. Filaments responding to the CFX67b probe also exhibited the type 0914 morphology but were less frequent, although again occurring in similarly configured plants. All these filaments showed an uneven FISH signal suggesting their ribosomes are localized at the ends of their cells. Furthermore, some generated distinctive FISH signals in all biomass samples containing them, where only certain cells within any single trichome fluoresced with probes designed against different target sites. Helper probes for each of these were required before all cells fluoresced above the visual detection limits of FISH.

  19. Removal of heavy metals from sewage sludge by extraction with organic acids

    NARCIS (Netherlands)

    Veeken, A.H.M.; Hamelers, H.V.M.


    Waste water treatment in activated sludge plants results in the production of large amounts of surplus sludge. After composting the sludge can be reused as fertiliser and soil conditioner in agriculture. Compared to landfilling and incineration, utilisation of sludge-compost is a more sustainable tr

  20. Study of the thermal decomposition of petrochemical sludge in a pilot plant reactor


    Conesa Ferrer, Juan Antonio; Moltó Berenguer, Julia; Ariza, José; Ariza, María; García Barneto, Agustín


    The pyrolysis of a sludge produced in the waste water treatment plant of an oil refinery was studied in a pilot plant reactor provided with a system for condensation of semivolatile matter. The study comprises experiments at 350, 400, 470 and 530 °C in nitrogen atmosphere. Analysis of all the products obtained (gases, liquids and chars) are presented, with a thermogravimetric study of the char produced and analysis of main components of the liquid. In the temperature range studied, the compos...

  1. The agricultural use of water treatment plant sludge: pathogens and antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Ignacio Nadal Rocamora


    Full Text Available The use of water treatment plant sludge to restore degraded soils is customary agricultural practice, but it could be dangerous from the point of view of both health and the environment. A transient increase of either pathogenic or indicator microbial populations, whose persistence in time is variable and attributed to the characteristics of the soil (types of materials in the soil, any amendments (origin and treatments it has undergone or the weather (humidity and temperature mainly, has often been detected in soils treated with this kind of waste. Given their origin, water treatment plant sludges could lead to the transmission of a pathogens and b antibiotic-resistant microorganisms to human beings through the food chain and cause the spreading of antibiotic resistances as a result of their increase and persistence in the soil for variable periods of time. However, Spanish legislation regulating the use of sludges in the farming industry is based on a very restricted microbiological criterion. Thus, we believe better parameters should be established to appropriately inform of the state of health of soils treated with water treatment plant sludge, including aspects which are not presently assessed such as antibiotic resistance.

  2. Anoxic Activated Sludge Monitoring with Combined Nitrate and Titrimetric Measurements

    DEFF Research Database (Denmark)

    Petersen, B.; Gernaey, Krist; Vanrolleghem, P.A.


    An experimental procedure for anoxic activated sludge monitoring with combined nitrate and titrimetric measurements is proposed and evaluated successfully with two known carbon sources, (-)acetate and dextrose. For nitrate measurements an ion-selective nitrate electrode is applied to allow...... was with the carbon source in excess, since excess nitrate provoked nitrite build-up thereby complicating the data interpretation. A conceptual model could quantitatively describe the experimental observations and thus link the experimentally measured proton production with the consumption of electron acceptor...... and carbon source during denitrification....

  3. Ecotoxicity Assessment of Stabilized Sewage Sludge from Municipal Sewage Treatment Plant

    Directory of Open Access Journals (Sweden)

    Włodarczyk Elżbieta


    Full Text Available Aim of this study was to evaluate the ecotoxicity of municipal sewage sludge conditioned with polyelectrolytes, taken from selected sewage treatment plant. Using the bioindication analysis overall toxicity was assessed, which allows to know the total toxicity of all the harmful substances contained in sewage sludge, in many cases acting synergistically. To prepare a sample of sludge for the basic test, all analyses were performed with a ratio of liquid to solid of 10:1 (water extract. Daphnia pulex biological screening test was used. A dilution series of an water extract of sludge were prepared to include within its scope the lowest concentration that causes 100% effect and the highest producing less than 10% of the effect within a specified range of the assay. The results of the test were read after 24 and 48 hours. Based on the research and analysis of test results it proved that the sewage sludge conditioned with polyelectrolytes exhibit the characteristics of eco-toxic.

  4. Preparation of sludge-based activated carbon and its application in dye wastewater treatment. (United States)

    Wang, Xiaoning; Zhu, Nanwen; Yin, Bingkui


    A novel activation process was adopted to produce highly porous activated carbon from cyclic activated sludge in secondary precipitator in municipal wastewater treatment plant for dye removal from colored wastewater. The physical properties of activated carbon produced with the activation of 3M KOH solution in the atmosphere of steam were investigated. Adsorption removal of a dye, Acid Brilliant Scarlet GR, from aqueous solution onto the sludge-based activated carbon was studied under varying conditions of adsorption time, initial concentration, carbon dosage and pH. Adsorption equilibrium was obtained in 15 min for the dye initial concentration of 300 mg/L. Initial pH of solution had an insignificant impact on the dye removal. Results indicated that 99.7% coloration and 99.6% total organic carbon (TOC) were removed after 15 min adsorption in the synthetic solution of Acid Brilliant Scarlet GR with initial concentration of 300 mg/L of the dye and 20 g/L activated carbon. The Langmuir and Freundlich equilibrium isotherm models fitted the adsorption data well with R(2)=0.996 and 0.912, respectively. Accordingly, it is concluded that the procedure of developing activated carbon used in this study could be effective and practical for utilizing in dye wastewater treatment.

  5. Studies of ultrasound disintegration of residual sludge and its energy consumption in water treatment of petrochemical plant

    Institute of Scientific and Technical Information of China (English)

    SHEN Jinfeng; YIN Xuan; GU Heping; L(U) Xiaoping


    To investigate the influence of ultrasound pretreatment on sludge anaerobic digestion,the ultrasound disintegration of residual sludge in water treatment of petrochemical plant was studied,and the mechanisms of ultrasound and medium were introduced.Experimental results indicate that ultrasound cavitation induces the rise of sludge temperature,which improves ultrasound disintegration on sludge.Ultrasound pretreatment can advance observably the quantity of chemical oxygen demand in sludge supernatant fluid (SCOD),which increases with ultrasound intensity and sonication time.The degree of ultrasound disintegration increases with the specific energy input.When the specific energy input is 10 000 kJ/kg of total dry solids,the degree of ultrasonic sludge disintegration reaches 40%.

  6. Energy potential and alternative usages of biogas and sludge from UASB reactors: case study of the Laboreaux wastewater treatment plant. (United States)

    Rosa, A P; Conesa, J A; Fullana, A; Melo, G C B; Borges, J M; Chernicharo, C A L


    This work assessed the energy potential and alternative usages of biogas and sludge generated in upflow anaerobic sludge blanket reactors at the Laboreaux sewage treatment plant (STP), Brazil. Two scenarios were considered: (i) priority use of biogas for the thermal drying of dehydrated sludge and the use of the excess biogas for electricity generation in an ICE (internal combustion engine); and (ii) priority use of biogas for electricity generation and the use of the heat of the engine exhaust gases for the thermal drying of the sludge. Scenario 1 showed that the electricity generated is able to supply 22.2% of the STP power demand, but the thermal drying process enables a greater reduction or even elimination of the final volume of sludge to be disposed. In Scenario 2, the electricity generated is able to supply 57.6% of the STP power demand; however, the heat in the exhaust gases is not enough to dry the total amount of dehydrated sludge.

  7. "Recovery of Iron Coagulants From Tehran Water-Treatment-Plant Sludge for Reusing in Textile Wastewater Treatment"

    Directory of Open Access Journals (Sweden)

    F Vaezi


    Full Text Available Most of the water treatment plants in Iran discharge their sludge to the environment whithout consideration of possible side effects. Since this kind of sludge is generally considered pollutant, the sludge treatment of water industry seems to be an essential task. Obviously theweight and volume of solids produced during the coagulation process are much more than other wastes of water treatment operations, and their treatment is much more difficult as well. Besides, this sludge contains metal hydroxide so disposing of it would waste considerable amounts of valuable metal salts. To face the mentioned problems, reclamation of coagulatns from waste sludges for reuse has been investigated in this research. Among different chemicals used in the experiments of recovery, sulfuric-acid showed better results from both practical and cost viewpoints. Three important phenomena were observed by sludge acidificantion: dissolution of metal hydroxide, reduction of sludge volume and finally faster settleability and dryness of remainder sludge. The salt recovered by sulfuric acid from the sludges of Tehran Water-Treatment Plant was ferric sulfate which showed good results in the treatment of two different types of wastewaters from textile industry.

  8. Hydrolytic activity of alpha-amylase in anaerobic digested sludge. (United States)

    Higuchi, Y; Ohashi, A; Imachi, H; Harada, H


    Hydrolysis is usually considered to be a rate-limiting step in anaerobic digestion. For improving anaerobic solid waste treatments, it is essential to elucidate the mechanism of hydrolysis. In this study, alpha-amylase, one of the hydrolytic enzymes, was investigated for the elucidation of more precise mechanism of hydrolysis. Alpha-amylase activity of solid starch-degrading bacteria (SDB) was estimated through batch experiments with several different substrates and with distinction between cell-bound and cell-free alpha-amylase. Monitoring of newly isolated strains of SDB was done by fluorescence in situ hybridization. Results indicated that cell-bound alpha-amylase is chiefly responsible for the hydrolysis in the digested sludge, providing very useful information that the contact between microbial cells and solids is significantly important. The activity of alpha-amylase of the digested sludge remained quite low when not required, but increased as they recognized appropriate substrates. Several-fold higher activity was obtained for starch or maltose as compared to glucose only.

  9. Foaming Scum Index (FSI)--a new tool for the assessment and characterisation of biological mediated activated sludge foams. (United States)

    Fryer, Martin; Gray, N F


    The formation of thick stable brown foams within the activated sludge process has become a familiar operational problem. Despite much research having already been carried out into establishing the causes of activated sludge foaming there is still no general consensus on the mechanisms involved. Historically investigation into activated sludge foaming has involved either measuring, under aeration conditions, the propensity of mixed liquor samples to foam, or evaluating different physico-chemical properties of the sludge which have previously been linked to activated sludge foaming. Both approaches do not present a means to quantify the risk posed to the treatment plants once foams have started to develop on the surface of aeration basins and final clarifiers. The Foaming Scum Index (FSI) is designed to offer a means to quantify risk on the basis of different foam characteristics which can easily be measured. For example, foam stability, foam coverage, foam suspended solids content and biological composition. The FSI was developed by measuring foam samples taken from several different domestic and municipal wastewater treatment sites located in Greater Dublin area (South-East Ireland). Path analysis was used to predict co-dependencies among the different sets of variables following a number of separate hypotheses. The standardized beta coefficients (β) produced from the multivariate correlation analysis (providing a measure of the contribution of each variable in the structural equation model) was used to finalise the weighting of each parameter in the index accordingly. According to this principal, foam coverage exerted the greatest influence on the overall FSI (β = 0.33), whilst the filamentous bacterial composition in terms of the filament index of foam, provided the least (β = 0.03). From this work it is proposed that the index can be readily applied as a standard tool in the coordination of research into the phenomenon of activated sludge foaming.

  10. Effects of waste activated sludge and surfactant addition on primary sludge hydrolysis and short-chain fatty acids accumulation. (United States)

    Ji, Zhouying; Chen, Guanlan; Chen, Yinguang


    This paper focused on the effects of waste activated sludge (WAS) and surfactant sodium dodecylbenzene sulfonate (SDBS) addition on primary sludge (PS) hydrolysis and short-chain fatty acids (SCFA) accumulation in fermentation. The results showed that sludge hydrolysis, SCFA accumulation, NH(4)(+)-N and PO(4)(3-)-P release, and volatile suspended solids (VSS) reduction were increased by WAS addition to PS, which were further increased by the addition of SDBS to the mixture of PS and WAS. Acetic, propionic and valeric acids were the top three SCFA in all experiments. Also, the fermentation liquids of PS, PS+WAS, and PS+WAS+SDBS were added, respectively, to municipal wastewater to examine their effects on biological municipal wastewater treatment, and the enhancement of both wastewater nitrogen and phosphorus removals was observed compared with no fermentation liquid addition.

  11. Improving Settling Dynamics of Activated Sludge by Adding Fine Talc Powder

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Larsen, Torben; Clauss, F.


    . The settling velocity was measured with a recirculated settling column under different concentrations and turbulence levels. Numerical simulation of a secondary settling tank indicates that adding fine powder will improve the overall performance considerably.......The effect of adding varying mixtures of talc and chlorite powder to activated sludge in order to improve the settling characteristic has been studied. The powder is found to improve the settling velocity of the sludge, strictly by increasing the average density of the sludge floc aggregate...

  12. Comparison of the Modeling Approach between Membrane Bioreactor and Conventional Activated Sludge Processes

    DEFF Research Database (Denmark)

    Jiang, Tao; Sin, Gürkan; Spanjers, Henri;


    Activated sludge models (ASM) have been developed and largely applied in conventional activated sludge (CAS) systems. The applicability of ASM to model membrane bioreactors (MBR) and the differences in modeling approaches have not been studied in detail. A laboratory-scale MBR was modeled using ASM...

  13. Presence of radionuclides in sludge from conventional drinking water treatment plants. A review. (United States)

    Fonollosa, E; Nieto, A; Peñalver, A; Aguilar, C; Borrull, F


    The analysis of sludge samples generated during water treatment processes show that different radioisotopes of uranium, thorium and radium, among others can accumulate in that kind of samples, even the good removal rates obtained in the aqueous phase (by comparison of influent and effluent water concentrations). Inconsequence, drinking water treatment plants are included in the group of Naturally Occurring Radioactive Material (NORM) industries. The accumulation of radionuclides can be a serious problem especially when this sludge is going to be reused, so more exhaustive information is required to prevent the possible radiological impact of these samples in the environment and also on the people. The main aim of this review is to outline the current situation regarding the different studies reported in the literature up to date focused on the analysis of the radiological content of these sludge samples from drinking water treatment plants. In this sense, special attention is given to the recent approaches for their determination. Another important aim is to discuss about the final disposal of these samples and in this regard, sludge reuse (including for example direct agricultural application or also as building materials) are together with landfilling the main reported strategies.

  14. Purification of total DNA extracted from activated sludge

    Institute of Scientific and Technical Information of China (English)


    Purification of the total DNA extracted from activated sludge samples was studied. The effects of extraction buffers and lysis treatments (lysozyme, sodium dodecyl sulfate (SDS), sonication, mechanical mill and thermal shock) on yield and purity of the total DNA extracted from activated sludge were investigated. It was found that SDS and mechanical mill were the most effective ways for cell lysis, and both gave the highest DNA yields, while by SDS and thermal shock, the purest DNA extract could be obtained. The combination of SDS with other lysis treatment, such as sonication and thermal shock, could apparently increase the DNA yields but also result in severe shearing. For the purification of the crude DNA extract, polyvinyl polypyrrolidone was used for the removal of humic contaminants. Cetyltrimethyl ammonium bromide, potassium acetate and phenol/chloroform were used to remove proteins and polysaccharides from crude DNA. Crude DNA was further purified by isopropanol precipitation. Thus, a suitable protocol was proposed for DNA extraction, yielding about 49.9 mg (DNA)/g volatile suspended solids, and the DNA extracts were successfully used in PCR amplifications for 16S rDNA and 16S rDNA V3 region. The PCR products of 16S rDNA V3 region allowed the DGGE analysis (denatured gradient gel electrophoresis) to be possible.

  15. Influences of influent carbon source on extracellular polymeric substances (EPS) and physicochemical properties of activated sludge. (United States)

    Ye, Fenxia; Peng, Ge; Li, Ying


    It is necessary to understand the bioflocculation, settling and dewatering characteristics in the activated sludge process in order to establish more efficient operational strategies. The influences of carbon source on the extracellular polymeric substances (EPS) and flocculation, settling and dewatering properties of the activated sludge were investigated. Laboratory-scale completely mixed activated sludge processes were used to grow the activated sludge with different carbon sources of starch, glucose and sodium acetate. The sludge fed with acetate had highest loosely bound EPS (LB-EPS) and that fed with starch lowest. The amount of tightly bound EPS (TB-EPS), protein content in LB-EPS, polysaccharide content and protein contents in TB-EPS, were independent of the influent carbon source. The polysaccharide content in LB-EPS of the activated sludge fed with sodium acetate was lower slightly than those of starch and glucose. The sludge also had a nearly consistent flocs size and the sludge volume index (SVI) value. ESS content of the sludge fed with sodium acetate was higher initially, although it was similar to those fed with glucose and starch finally. However, the specific resistance to filtration and normalized capillary suction time fluctuated first, but finally were stable at around 5.0×10(8)mkg(-1) and 3.5 s Lg(-1) SS, respectively. Only the protein content in LB-EPS weakly correlated with the flocs size and SVI of the activated sludge. But there was no correlation between any other EPS contents or components and the physicochemical properties of the activated sludge.

  16. Exploring the relationship between viscous bulking and ammonia-oxidiser abundance in activated sludge: A comparison of conventional and IFAS systems. (United States)

    van den Akker, Ben; Beard, Helen; Kaeding, Uwe; Giglio, Steven; Short, Michael D


    This study investigated the nature of viscous sludge bulking within a molasses-fed integrated fixed-film activated sludge (IFAS) and conventional activated sludge (AS) plant by routinely measuring the total carbohydrate and protein fractions of the mixed liquor (ML). The impacts of sludge settleability and plant performance on the relative abundance of ammonia-oxidising bacteria (AOB) (Nitrosomonas oligotropha-cluster) were also investigated using quantitative polymerase chain reaction (qPCR). Results showed that sludge volume index (SVI) correlated positively with the amount of ML total carbohydrate in both the IFAS and traditional AS plants, highlighting the influential role that ML polysaccharide concentration plays on sludge settleability in these reactors. Results also revealed a negative relationship between the AOB/total Bacteria ratio and SVI, demonstrating that a poor settling sludge generally coincided with periods of relatively low AOB abundance. The existence of these relationships suggests that readily available organic carbon (molasses) was likely to have been present in excess in these systems. Our qPCR results also showed that concentrations of both AOB and total Bacteria genomic copies detected within the ML of the IFAS and conventional AS plants were remarkably similar. For the IFAS system, results showed that the ML supported an equivalent number of AOB (per gram of biomass) to that detected on the plastic IFAS media carriers, suggesting that the suspended biomass fraction plays an equally important role in the overall nitrification performance of these systems. Interestingly, large observed variations in AOB and AOB/total Bacteria ratio measured within both the ML and IFAS media carriers had no measurable impact on the apparent nitrification performance of these systems; indicating the presence of some excess or 'reserve' nitrifying capacity above that which is required for effective plant performance. Results presented here also constitute the

  17. Stabilization and dewatering of wastewater treatment plants sludge using the Fenton process

    Directory of Open Access Journals (Sweden)

    Abolfazl Azhdarpoor


    Full Text Available Wastewater sludge typically contains large amounts of water and organic materials; therefore, its stabilization and dewatering is of particular importance. In this study, Fenton oxidation process is used for stabilization and dewatering of sludge in the output of a wastewater treatment plant. To evaluate the sludge stabilization and dewatering, specific resistance to filtration (SRF, volatile organic compounds (VSS, total suspended solids (TSS, soluble chemical oxygen demand (SCOD and heterotrophic bacteria were measured. During the experiment, the optimal values of various parameters such as pH (2-9, hydrogen peroxide (0.015- 0.18mol/L, Fe2+ (0.008- 0.1mol/L and time (5 - 60 minutes for optimum sludge dewatering and stabilization were investigated. The results showed that the highest percentages of SRF reduction and removal rates of SCOD, VSS and TSS were 99.48, 61, 42, and 41 percent respectively. These results were obtained in optimum pH 5, 0.05 mol/l Fe2+, 0.12 mol/l hydrogen peroxide, and the retention time of 15 minutes. The removal rate of heterotrophic bacteria increased with increasing dose of hydrogen peroxide, so that a removal rate of 84 percent was observed at a dose of 0.18 mol/l. In general, Fenton process can reduce volatile organic materials and chemical oxygen demand of the sludge resulting in its significant stabilization and dewatering. In general, Fenton process can reduce volatile organic materials and chemical oxygen demand of the sludge resulting in its significant stabilization and dewatering.

  18. Simulation and optimization of a coking wastewater biological treatment process by activated sludge models (ASM). (United States)

    Wu, Xiaohui; Yang, Yang; Wu, Gaoming; Mao, Juan; Zhou, Tao


    Applications of activated sludge models (ASM) in simulating industrial biological wastewater treatment plants (WWTPs) are still difficult due to refractory and complex components in influents as well as diversity in activated sludges. In this study, an ASM3 modeling study was conducted to simulate and optimize a practical coking wastewater treatment plant (CWTP). First, respirometric characterizations of the coking wastewater and CWTP biomasses were conducted to determine the specific kinetic and stoichiometric model parameters for the consecutive aeration-anoxic-aeration (O-A/O) biological process. All ASM3 parameters have been further estimated and calibrated, through cross validation by the model dynamic simulation procedure. Consequently, an ASM3 model was successfully established to accurately simulate the CWTP performances in removing COD and NH4-N. An optimized CWTP operation condition could be proposed reducing the operation cost from 6.2 to 5.5 €/m(3) wastewater. This study is expected to provide a useful reference for mathematic simulations of practical industrial WWTPs.

  19. Continuous thermal hydrolysis and energy integration in sludge anaerobic digestion plants. (United States)

    Fdz-Polanco, F; Velazquez, R; Perez-Elvira, S I; Casas, C; del Barrio, D; Cantero, F J; Fdz-Polanco, M; Rodriguez, P; Panizo, L; Serrat, J; Rouge, P


    A thermal hydrolysis pilot plant with direct steam injection heating was designed and constructed. In a first period the equipment was operated in batch to verify the effect of sludge type, pressure and temperature, residence time and solids concentration. Optimal operation conditions were reached for secondary sludge at 170 degrees C, 7 bar and 30 minutes residence time, obtaining a disintegration factor higher than 10, methane production increase by 50% and easy centrifugation In a second period the pilot plant was operated working with continuous feed, testing the efficiency by using two continuous anaerobic digester operating in the mesophilic and thermophilic range. Working at 12 days residence time, biogas production increases by 40-50%. Integrating the energy transfer it is possible to design a self-sufficient system that takes advantage of this methane increase to produce 40% more electric energy.

  20. Effects of Metal Nanoparticles on Methane Production from Waste-Activated Sludge and Microorganism Community Shift in Anaerobic Granular Sludge (United States)

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


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

  1. Basic Data Report -- Defense Waste Processing Facility Sludge Plant, Savannah River Plant 200-S Area

    Energy Technology Data Exchange (ETDEWEB)

    Amerine, D.B.


    This Basic Data Report for the Defense Waste Processing Facility (DWPF)--Sludge Plant was prepared to supplement the Technical Data Summary. Jointly, the two reports were intended to form the basis for the design and construction of the DWPF. To the extent that conflicting information may appear, the Basic Data Report takes precedence over the Technical Data Summary. It describes project objectives and design requirements. Pertinent data on the geology, hydrology, and climate of the site are included. Functions and requirements of the major structures are described to provide guidance in the design of the facilities. Revision 9 of the Basic Data Report was prepared to eliminate inconsistencies between the Technical Data Summary, Basic Data Report and Scopes of Work which were used to prepare the September, 1982 updated CAB. Concurrently, pertinent data (material balance, curie balance, etc.) have also been placed in the Basic Data Report. It is intended that these balances be used as a basis for the continuing design of the DWPF even though minor revisions may be made in these balances in future revisions to the Technical Data Summary.

  2. Kinetics of continuous biodegradation of pesticide organic wastewater by activated carbon-activated sludge

    Institute of Scientific and Technical Information of China (English)


    Organic triazophos wastewater was continuously treated with Rhodopseudomonas capsulatus and activated carbon and activated sludge system(PACT-AS) in a plug bioreactor. A kinetic model of PACT-AS wastewater treatment system was established to provide an useful basis for further simulate scale-up treatment of toxic organic wastewater.

  3. Two proposals for pumping calculations of non–newtonian fluids, water treatment plants disposal sludges case


    H. Gardea–Villegas


    This paper presents two ways to calculate the pumping power of non Newtonian fluids and especially yield pseudoplastics which are the kind of disposal fluids from Water Treatment Plants. Fluids called sludges. The proposals included here, are based in methods suggested by Levenspiel (1986) applicable to determine the performance of Bingham plastics and pseudoplastic fluids using a graphical approximation of the rheological behavior of these materials. This approach has the advantage that is a...

  4. Adsorption of reactive brilliant red K-2BP on activated carbon developed from sewage sludge

    Institute of Scientific and Technical Information of China (English)

    Jiankun XIE; Qinyan YUE; Hui YU; Wenwen YUE; Renbo LI; Shengxiao ZHANG; Xiaona WANG


    Activated carbon was prepared from the sewage sludge of municipal wastewater treatment plant by chemical activation (activation reagent is ZnCl2) and was used for the adsorption of dye (reactive brilliant red K-2BP). The impact of adsorbent amount, adsorption time and pH value on adsorption effect, the adsorption kinetics, and the adsorption thermodynamics were dis-cussed according to batch adsorption tests. The results indicated that the activated carbon developed from sewage sludge (ACSS), which was mesoporous, possessed opened porous structures. The iodine number of the ACSS was heavy metals in the leachate didn't exceed the contents limit. The adsorption kinetics of reactive brilliant red K-2BP on the ACSS was accorded with the two-step kinetics rate equation and pseudo-second-order kinetics equation. Compared to the Freundlich isotherm equation, the Langmuir isotherm equation showed better applicability for the adsorption. The adsorption which was favorable was an endothermic (enthalpy △H > 0) and spontaneous (flee energy △G 0).

  5. Identification and quantification of nitrogen nutrient deficiency in the activated sludge process using respirometry

    NARCIS (Netherlands)

    Ning, Z.; Patry, G.G.; Spanjers, H.


    Experimental protocols to identify and quantify nitrogen nutrient deficiency in the activated sludge process were developed and tested using respirometry. Respirometric experiments showed that when a nitrogen nutrient deficient sludge is exposed to ammonia nitrogen, the oxygen uptake rate (OUR) of t

  6. New insight into the biological treatment by activated sludge: the role of adsorption process. (United States)

    Zhang, Xiaochun; Li, Xinrun; Zhang, Qingrui; Peng, Qiuming; Zhang, Wen; Gao, Faming


    The objective of this study was to evaluate the effect of adsorption on the biological treatment process of wastewater. In the absence of substrate in the water, activated sludge developed well in the first hour, indicating that the growth of microorganism was not directly related to substrate concentration and the dissolved organic matter in the water assays were performed, no organic matter was detected out, revealing that there was no desorption in the activated sludge adsorption process. Activated sludge batch growth experiments in the presence of different adsorption capacities indicated that specific growth rate increased as specific adsorption capacity increased. The experiment on the relationship of adsorption capacity and substrate concentration or sludge concentration was also carried out. Specific adsorption capacity increased as sludge load increased, presenting linear correlation. The experiment results showed that adsorption should be taken into account in the study of the biological treatment process of wastewater.

  7. Development of a model describing virus removal process in an activated sludge basin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T.; Shiragami, N. Unno, H. [Tokyo Institute of Technology, Tokyo (Japan)


    The virus removal process from the liquid phase in an activated sludge basin possibly consists of physicochemical processes, such as adsorption onto sludge flocs, biological processes such as microbial predating and inactivation by virucidal components excreted by microbes. To describe properly the virus behavior in an activated sludge basin, a simple model is proposed based on the experimental data obtained using a poliovirus type 1. A three-compartments model, which include the virus in the liquid phase and in the peripheral and inner regions of sludge flocs is employed. By using the model, the Virus removal process was successfully simulated to highlight the implication of its distribution in the activated sludge basin. 17 refs., 8 figs.

  8. Dynamic fouling behaviors of submerged nonwoven bioreactor for filtration of activated sludge with different SRT. (United States)

    Chuang, Shun-Hsing; Lin, Po-Kuen; Chang, Wei-Chin


    The flux variations and resistances accumulated during filtration of activated sludge with sludge retention time (SRT) of 15, 30, and 60 days were analyzed to investigate the dynamic fouling behavior in a submerged nonwoven bioreactor. Different SRT values varied sludge condition and particle size distribution in the supernatants, which caused dissimilar fouling characteristics. Short-term fouling of the nonwoven bioreactor during filtration of activated sludge with SRT of 15 days was fully reversible, and the resistance percentages of solutes, colloids, and suspended solids were 6%, 27%, and 67%, respectively. On the other hand, significant increases of colloid resistance, such as with the filtration of activated sludge with SRT of 30 and 60 days, were related to the occurrence of irreversible fouling. The phenomenon of pore blocking by particles or colloids with size analogous to the pore of nonwoven fabric was a decisive factor leading to irreversible fouling in the large-pore materials.

  9. Levels and distributions of polychlorinated biphenyls in sewage sludge of urban wastewater treatment plants

    Institute of Scientific and Technical Information of China (English)

    GUO Li; ZHANG Bing; XIAO Ke; ZHANG Qinghua; ZHENG Minghui


    Concentrations of polychlorinated biphenyls (PCBs) have been measured in sewage sludge samples from 8 urban wastewater treatment plants in Beijing, China. The PCB congeners were analyzed by isotope dilution high resolution gas chromatography/high resolution mass spectrometry method. The concentration of PCBs ranged from 65.6 to 157 ng/g dry weight (dw), with a mean value of 101 ng/g dw. The dioxin-like PCB WHO-TEQs (World Health Organization-Toxic Equivalents) of the sludge were lower than 1 pg /g dw. Consequently, all the concentrations of PCBs in sludge samples were below the upper limit for land application according to the Chinese legislation law for agriculture use. The PCB homologue profiles in sludge samples were dominated by tri-CBs and tetra-CBs. Similar distributions have been found in one of the Chinese PCB commercial products. The patterns of dioxin-like and indicator congeners observed in this study were quite similar in all samples. The predominant congener for dioxin-like and indicator PCBs were PCB-118 and PCB-28, respectively, while PCB-126 had the highest TEQ value.

  10. Dynamics of the microfauna community in a full-scale municipal wastewater treatment plant experiencing sludge bulking. (United States)

    Hu, Bo; Qi, Rong; An, Wei; Xu, Muqi; Zhang, Yu; Bai, Xue; Bao, Haipeng; Wen, Yang; Gu, Jian; Yang, Min


    We investigated the dynamics of the microfauna community in activated sludge, with special reference to sludge bulking, in two parallel municipal wastewater treatment systems in Beijing, China over a period of 14 months. Annual cyclic changes in microfauna community structures occurred in both systems. RELATE analysis based on Spearman's Rank correlation indicated that microfauna community structures were highly correlated with the sludge volume index (SVI) (pVorticella striata increased significantly with an increase in SVI (p<0.001) and decrease in water temperature (p<0.001), suggesting that sludge bulking may have created favorable conditions for the two species, even under unfavorable temperature conditions. Sludge de-flocculation primarily due to the excessive growth of Microthrix parvicella-like filaments could be an important driving force for the microfauna community changes. The release of flocculated non-filamentous bacteria may represent a suitable food source for these species. The two species may be considered as potential bioindicators for sludge bulking.

  11. Sludge stabilization at the Plutonium Finishing Plant, Hanford Site, Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)


    This Environmental Assessment evaluates the proposed action to operate two laboratory-size muffle furnaces in glovebox HC-21C, located in the Plutonium Finishing Plant (PFP), Hanford Site, Richland, Washington. The muffle furnaces would be used to stabilize chemically reactive sludges that contain approximately 25 kilograms (55 pounds) of plutonium by heating to approximately 500 to 1000{degrees}C (900 to 1800{degrees}F). The resulting stable powder, mostly plutonium oxide with impurities, would be stored in the PFP vaults. The presence of chemically reactive plutonium-bearing sludges in the process gloveboxes poses a risk to workers from radiation exposure and limits the availability of storage space for future plant cleanup. Therefore, there is a need to stabilize the material into a form suitable for long-term storage. This proposed action would be an interim action, which would take place prior to completion of an Environmental Impact Statement for the PFP which would evaluate stabilization of all plutonium-bearing materials and cleanout of the facility. However, only 10 percent of the total quantity of plutonium in reactive materials is in the sludges, so this action will not limit the choice of reasonable alternatives or prejudice the Record of Decision of the Plutonium Finishing Plant Environmental Impact Statement.

  12. Quantitative evaluation on the characteristics of activated sludge granules and flocs using a fuzzy entropy-based approach (United States)

    Fang, Fang; Qiao, Li-Li; Ni, Bing-Jie; Cao, Jia-Shun; Yu, Han-Qing


    Activated sludge granules and flocs have their inherent advantages and disadvantages for wastewater treatment due to their different characteristics. So far quantitative information on their evaluation is still lacking. This work provides a quantitative and comparative evaluation on the characteristics and pollutant removal capacity of granules and flocs by using a new methodology through integrating fuzzy analytic hierarchy process, accelerating genetic algorithm and entropy weight method. Evaluation results show a higher overall score of granules, indicating that granules had more favorable characteristics than flocs. Although large sized granules might suffer from more mass transfer limitation and is prone to operating instability, they also enable a higher level of biomass retention, greater settling velocity and lower sludge volume index compared to flocs. Thus, optimized control of granule size is essential for achieving good pollutant removal performance and simultaneously sustaining long-term stable operation of granule-based reactors. This new integrated approach is effective to quantify and differentiate the characteristics of activated sludge granules and flocs. The evaluation results also provide useful information for the application of activated sludge granules in full-scale wastewater treatment plants.

  13. Quantitative evaluation on the characteristics of activated sludge granules and flocs using a fuzzy entropy-based approach (United States)

    Fang, Fang; Qiao, Li-Li; Ni, Bing-Jie; Cao, Jia-Shun; Yu, Han-Qing


    Activated sludge granules and flocs have their inherent advantages and disadvantages for wastewater treatment due to their different characteristics. So far quantitative information on their evaluation is still lacking. This work provides a quantitative and comparative evaluation on the characteristics and pollutant removal capacity of granules and flocs by using a new methodology through integrating fuzzy analytic hierarchy process, accelerating genetic algorithm and entropy weight method. Evaluation results show a higher overall score of granules, indicating that granules had more favorable characteristics than flocs. Although large sized granules might suffer from more mass transfer limitation and is prone to operating instability, they also enable a higher level of biomass retention, greater settling velocity and lower sludge volume index compared to flocs. Thus, optimized control of granule size is essential for achieving good pollutant removal performance and simultaneously sustaining long-term stable operation of granule-based reactors. This new integrated approach is effective to quantify and differentiate the characteristics of activated sludge granules and flocs. The evaluation results also provide useful information for the application of activated sludge granules in full-scale wastewater treatment plants. PMID:28211540

  14. Anaerobic co-digestion of waste activated sludge and greasy sludge from flotation process: batch versus CSTR experiments to investigate optimal design. (United States)

    Girault, R; Bridoux, G; Nauleau, F; Poullain, C; Buffet, J; Peu, P; Sadowski, A G; Béline, F


    In this study, the maximum ratio of greasy sludge to incorporate with waste activated sludge was investigated in batch and CSTR experiments. In batch experiments, inhibition occurred with a greasy sludge ratio of more than 20-30% of the feed COD. In CSTR experiments, the optimal greasy sludge ratio was 60% of the feed COD and inhibition occurred above a ratio of 80%. Hence, batch experiments can predict the CSTR yield when the degradation phenomenon are additive but cannot be used to determine the maximum ratio to be used in a CSTR configuration. Additionally, when the ratio of greasy sludge increased from 0% to 60% of the feed COD, CSTR methane production increased by more than 60%. When the greasy sludge ratio increased from 60% to 90% of the feed COD, the reactor yield decreased by 75%.


    Directory of Open Access Journals (Sweden)

    Agnieszka Godlewska


    Full Text Available The study aimed at determining changes in the contents of selected metals in the biomass of test plants due to fertilisation with fresh and composted sewage sludge, hard coal ash, and sludge-ash mixture, as well as liming at a background of mineral nutrition. The experimental design was a completely randomised arrangement with three replicates. The following factors were examined: fertilisation with organic and mineral materials (fresh sewage sludge; composted sewage sludge; hard coal ash; calcium carbonate and mineral fertilisation (no fertilisation; NPK fertilisation. An application of sewage sludge, hard coal ash, and sludge-ash mixture significantly increased maize content of barium. Addition of hard coal ash into sewage sludge contributed to an increase in lead content determined in cocksfoot biomass harvested from the first and second cut, and barium in maize biomass. Soil liming significantly affected barium content the biomass of plants harvested from the first and second cut, as well as in maize biomass. NPK nutrition significantly increased barium concentrations in the biomass of test plants and maize.

  16. Biodegradation of pharmaceuticals in hospital wastewater by a hybrid biofilm and activated sludge system (Hybas). (United States)

    Escolà Casas, Mònica; Chhetri, Ravi Kumar; Ooi, Gordon; Hansen, Kamilla M S; Litty, Klaus; Christensson, Magnus; Kragelund, Caroline; Andersen, Henrik R; Bester, Kai


    Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process (hybrid biofilm and activated sludge system (Hybas™)) has been suggested as a possible solution for hospital wastewater treatment. To investigate the potential of such a hybrid system for the removal of pharmaceuticals in hospital wastewater a pilot plant consisting of a series of one activated sludge reactor, two Hybas™ reactors and one moving bed biofilm reactor (MBBR) has been established and adapted during 10 months of continuous operation. After this adaption phase batch and continuous experiments were performed for the determination of degradation of pharmaceuticals. Removal of organic matter and nitrification mainly occurred in the first reactor. Most pharmaceuticals were removed significantly. The removal of pharmaceuticals (including X-ray contrast media, β-blockers, analgesics and antibiotics) was fitted to a single first-order kinetics degradation function, giving degradation rate constants from 0 to 1.49 h(-1), from 0 to 7.78 × 10(-1)h(-1), from 0 to 7.86 × 10(-1)h(-1) and from 0 to 1.07 × 10(-1)h(-1) for first, second, third and fourth reactors respectively. Generally, the highest removal rate constants were found in the first and third reactors while the lowest were found in the second one. When the removal rate constants were normalized to biomass amount, the last reactor (biofilm only) appeared to have the most effective biomass in respect to removing pharmaceuticals. In the batch experiment, out of 26 compounds, 16 were assessed to degrade more than 20% of the respective pharmaceutical within the Hybas™ train. In the continuous flow experiments, the measured removals were similar to those estimated from the batch experiments, but the concentrations of a few pharmaceuticals appeared to increase during the first treatment step. Such increase

  17. Nitrogen removal from wastewater and external waste activated sludge reutilization/reduction by simultaneous sludge fermentation, denitrification and anammox (SFDA). (United States)

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


    This work demonstrates the feasibility of simultaneous nitrogen removal and external waste activated sludge (WAS) reutilization/reduction by using the synergy of sludge fermentation, denitrification and anammox processes in up-flow reactors (SFDA). Pre-treated domestic wastewater and synthetic wastewater (containing nitrite ∼20mg/L, ammonium ∼10mg/L in both) were fed to 1# and 2# SFDA, respectively. Long-term operation of 1# SFDA was investigated with achieving the peak ammonium removal rate of 0.021 and nitrite removal rate of 0.081kgN/(m(3)d) as nitrogen loading rate elevated from 0.075 to 0.106kgN/(m(3)d). Negative effect of dissolved oxygen on anammox or fermentation in the 2# SFDA was demonstrated negligible due to rapid depletion by microorganisms. Furthermore, a "net" sludge reduction of 38.8% was obtained due to sludge decay and organics consumption by denitrification. The SFDA process was expected to potentially be used for nitrogen removal and WAS reutilization/reduction in full-scale application.


    Directory of Open Access Journals (Sweden)



    Full Text Available An activated sludge aeration tank and a sedimentation basin were used to treat Amol’s industrial park effluents originating from all industrial units. A continuous system was implemented and the kinetic parameters were measured.The parameters such as rate constant, substrate utilization rate constant, yield and decay coefficient were 2.12 d-1, 232.4 mg l-1, 0.33 g/g of substrate and 0.096 d−1, respectively. The hydraulic retention times (HRT were in the range of 9 to 27 h. The sludge recycle ratios in the range from 0.3 to 1 were considered. The COD removal, SVI and DO were determined and the optimal values were obtained. It was observed that at HRT of 16 h and the sludge recycle ratio of 0.85, the COD removal and SVI were 95 and 85 %, respectively. The sludge recycle ratio greater than 0.85 had no significant effect on the COD removal.

  19. [Comparative Metagenomics of BIOLAK and A2O Activated Sludge Based on Next-generation Sequencing Technology]. (United States)

    Tian, Mei; Liu, Han-hu; Shen, Xin


    This is the first report of comparative metagenomic analyses of BIOLAK sludge and anaerobic/anoxic/oxic (A2O) sludge. In the BIOLAK and A2O sludge metagenomes, 47 and 51 phyla were identified respectively, more than the numbers of phyla identified in Australia EBPR (enhanced biological phosphorus removal), USA EBPR and Bibby sludge. All phyla found in the BIOLAK sludge were detected in the A2O sludge, but four phyla were exclusively found in the A20 sludge. The proportion of the phylum Ignavibacteriae in the A2O sludge was 2.0440%, which was 3.2 times as much as that in the BIOLAK sludge (0.6376%). Meanwhile, the proportion of the bacterial phylum Gemmatimonadetes in the BIOLAK sludge was 2.4673%, which was >17 times as much as that in the A2O sludge (0.1404%). The proportion of the bacterial phylum Chlamydiae in the BIOLAK metagenome (0.2192%) was >6 times higher than that in the A2O (0.0360%). Furthermore, 167 genera found in the A20 sludge were not detected in the BIOLAK sludge. And 50 genera found in the BIOLAK sludge were not detected in the A20 sludge. From the analyses of both the phylum and genus levels, there were huge differences between the two biological communities of A2O and BIOLAK sludge. However, the proportions of each group of functional genes associated with metabolism of nitrogen, phosphor, sulfur and aromatic compounds in BIOLAK were very similar to those in A2O sludge. Moreover, the rankings of all six KEGG (Kyoto Encyclopedia for Genes and Genomes) categories were identical in the two sludges. In addition, the analyses of functional classification and pathway related nitrogen metabolism showed that the abundant enzymes had identical ranking in the BIOLAK and A2O metagenomes. Therefore, comparative metagenomics of BIOLAK and A2O activated sludge indicated similar function assignments from the two different biological communities.


    Energy Technology Data Exchange (ETDEWEB)

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


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

  1. The influence of amendment material on biosolid composting of sludge from a waste-water treatment plant

    Directory of Open Access Journals (Sweden)

    Patricia Torres Lozada


    Full Text Available Aerobic composting employing manual turning was evaluated by using the sludge produced by EMCALI EICE ESP's Cañaverlejo wastewater treatment plant (PTAR-C. Compost (in 1,0 ton piles consisted of sludge, a fixed proportion of bulking agent (10% and amendment material. Sugarcane waste and solid organic (marketplace waste were evaluated as amendment material using 20/80 and 40/60 weight/weight (amendment/sludge ratios. Incorporating the amendment material improved the compost, being reflected in a faster start for the thermophilic phase, higher temperatures beign maintained (>55°C and better C/N ratio obtained in the compost in all treatments compared to the pile which had no amendment added to it. Incorporating the bulking agent improved sludge manageability during composting; the best combination was 54% sludge + 10% sugacane bagasse + 36% liquid sugarcane waste.


    Directory of Open Access Journals (Sweden)



    Full Text Available In this study, the planing of the Activated Sludge Method used on Environmental Engineering, was done by MS Excel 8.0, which very commonly used for spread sheet design. The program contained five sections. They are; the "DATA" section to enter the available data for calculations, the "RESULTS" section to show the outcomes of calculations, the "DETERMINATION of DIMENSIONS" section to determine the dimensions of the reactor, the "CALCULATION of AIR DIFFUSER" section to calculate the dimensions and capacity of air diffuser and the "EVALUATION" section to evaluate the results of calculations according to the criteria. The aim of this study was, to demonstrate that every engineer ca do easily needed programs related to her or his field using Excel's functions although can not know about any program language.

  3. Selenite bioremediation potential of indigenous microorganisms from industrial activated sludge. (United States)

    Garbisu, C; Alkorta, I; Carlson, D E; Leighton, T; Buchanan, B B


    Ten bacterial strains were isolated from the activated sludge waste treatment system (BIOX) at the Exxon refinery in Benicia, California. Half of these isolates could be grown in minimal medium. When tested for selenite detoxification capability, these five isolates (members of the genera Bacillus, Pseudomonas, Enterobacter and Aeromonas), were capable of detoxifying selenite with kinetics similar to those of a well characterized Bacillus subtilis strain (168 Trp+) studied previously. The selenite detoxification phenotype of the Exxon isolates was stable to repeated transfer on culture media which did not contain selenium. Microorganisms isolated from the Exxon BIOX reactor were capable of detoxifying selenite. Treatability studies using the whole BIOX microbial community were also carried out to evaluate substrates for their ability to support growth and selenite bioremediation. Under the appropriate conditions, indigenous microbial communities are capable of remediating selenite in situ.

  4. Optimization of detecting hydrogenase activity for acidogenic fermentation of activated sludge

    Institute of Scientific and Technical Information of China (English)

    ZHENG Guo-chen; HE Jun-guo; LI Jian-zheng; AJAY Kumar Jha; ZHANG Li-guo


    In order to evaluate the hydrogen-producing efficiency of anaerobic activated sludge in Anaerobic Baffled Reactor(ABR)fermentation processes,the optimal conditions for hydrogen producing hydrogenase method on methyl viologen(MV)assay was used to detect the hydrogen production activity of the activated sludge.The most favorable parameters such as 0.6 mL sodium acetate buffer(pH 5.0),100 μL lysozyme,0.2 mL sodium di bromoethane(9.0 mmol/L)and 0.7 mmol/L iron added into 1 mL activated sludge(2.66~26.64 gMLVSS/L)were found.Furthermore,reaction temperature and culture time were detected as 40 ℃ and 30 min respectively.Sodium thiosulfate and sodium sulfides were taken as the reducing agent while trichloroacetic acid as terminator.Under the MV optimal conditions,micro-texic Dimethyl sulfoxide(DMSO)get higher security and better accuracy.The sensitivity of the detection methods(DMSO as electron carrier)was increased by more than30%.The results show that the optimal conditions can be applied to measure hydrogenase activity correlating with its specific hydrogen production rate in a hydrogen-producing anaerobic activated sludge system.

  5. Influence of plant growth on degradation of linear alkylbenzene sulfonate in sludge-amended soil. (United States)

    Mortensen, G K; Egsgaard, H; Ambus, P; Jensen, E S; Grøn, C


    Widespread application of sewage sludge to agricultural soils in Denmark has led to concern about the possible accumulation and effects of linear alkylbenzene sulfonate (LAS) in the soil ecosystem. Therefore, we have studied the uptake and degradation of LAS in greenhouse pot experiments. Sewage sludge was incorporated into a sandy soil to give a range from very low to very high applications (0.4 to 90 Mg dry wt. ha(-1)). In addition, LAS was added as water solutions. The soil was transferred to pots and sown with barley (Hordeum vulgare L. cv. Apex), rape (Brassica napus L. cv. Hyola 401), or carrot (Daucus carota L.). Also, plant-free controls were established. For all additions there was no plant uptake above the detection limit at 0.5 mg LAS kg(-1) d.w, but plant growth stimulated the degradation. With a growth period of 30 d, LAS concentrations in soil from pots with rape had dropped from 27 to 1.4 mg kg(-1) dry wt., but in plant-free pots the concentration decreased only to 2.4 mg kg(-1) dry wt. When LAS was added as a spike, the final concentration in soil from planted pots was 0.7 mg kg(-1) dry wt., but in pots without plants the final concentration was much higher (2.5 mg kg(-1) dry wt.). During degradation, the relative fraction of homologues C10, C11, and C12 decreased, while C13 increased.

  6. [Pilot study of thermal treatment/thermophilic anaerobic digestion process treating waste activated sludge of high solid content]. (United States)

    Wu, Jing; Wang, Guang-qi; Cao, Zhi-ping; Li, Zhong-hua; Hu, Yu-ying; Wang, Kai-jun; Zu, Jian-e


    A pilot-scale experiment about the process of "thermal pretreatment at 70°C/thermophilic anaerobic digestion" of waste activated sludge of high solid content (8% -9% ) was conducted. The process employed thermal treatment of 3 days to accelerate the hydrolysis and thermophilic digestion to enhance anaerobic reaction. Thus it was good at organic removal and stabilization. When the solid retention time (SRT) was longer than 20 days, the VSS removal rate was greater than 42. 22% and it was linearly correlated to the SRT of the aerobic digestion with the R2 of 0. 915 3. It was suggested that SRT of anaerobic digestion was 25 days in practice. VSS removal rate and biogas production rate of the pilot experiment were similar to those of the run-well traditional full-scale sludge anaerobic digestion plants (solid content 3% -5% ) and the plant of high solid content using German technique.

  7. Removal of Organic Micropollutants by Aerobic Activated Sludge

    KAUST Repository

    Wang, Nan


    The study examined the removal mechanism of non-acclimated and acclimated aerobic activated sludge for 29 target organic micropollutants (OMPs) at low concentration. The selection of the target OMPs represents a wide range of physical-chemical properties such as hydrophobicity, charge state as well as a diverse range of classes, including pharmaceuticals, personal care products and household chemicals. The removal mechanisms of OMPs include adsorption, biodegradation, hydrolysis, and vaporization. Adsorption and biodegradation were found to be the main routes for OMPs removal for all target OMPs. Target OMPs responded to the two dominant removal routes in different ways: (1) complete adsorption, (2) strong biodegradation and weak adsorption, (3) medium biodegradation and adsorption, and (4) weak sorption and weak biodegradatio. Kinetic study showed that adsorption of atenolol, mathylparaben and propylparaben well followed first-order model (R2: 0.939 to 0.999) with the rate constants ranging from 0.519-7.092 h-1. For biodegradation kinetics, it was found that benzafibrate, bisphenol A, diclofenac, gemfibrozil, ibuprofen, caffeine and DEET followed zero-order model (K0:1.15E-4 to 0.0142 μg/Lh-1, R2: 0.991 to 0.999), while TCEP, naproxen, dipehydramine, oxybenzone and sulfamethoxazole followed first-order model (K1:1.96E-4 to 0.101 h-1, R2: 0.912 to 0.996). 4 Inhibition by sodium azide (NaN3)and high temperature sterilization was compared, and it was found that high temperature sterilization will damage cells and change the sludge charge state. For the OMPs adaptation removal study, it was found that some of OMPs effluent concentration decreased, which may be due to the slow adaptation of the sludge or the increase of certain bacteria culture; some increased due to chromic toxicity of the chemicals; most of the OMPs had stable effluent concentration trend, it was explained that some of the OMPs were too difficutl to remove while other showed strong quick adaptation

  8. Hydrothermal Liquefaction and Upgrading of Municipal Wastewater Treatment Plant Sludge: A Preliminary Techno-Economic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Snowden-Swan, Lesley J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhu, Yunhua [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Susanne B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elliott, Douglas C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schmidt, Andrew J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hallen, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Billing, Justin M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hart, Todd R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fox, Samuel P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Maupin, Gary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    A preliminary process model and techno-economic analysis (TEA) was completed for fuel produced from hydrothermal liquefaction (HTL) of sludge waste from a municipal wastewater treatment plant (WWTP) and subsequent biocrude upgrading. The model is adapted from previous work by Jones et al. (2014) for algae HTL, using experimental data generated in fiscal year 2015 (FY15) bench-scale HTL testing of sludge waste streams. Testing was performed on sludge samples received from MetroVancouver’s Annacis Island WWTP (Vancouver, B.C.) as part of a collaborative project with the Water Environment and Reuse Foundation (WERF). The full set of sludge HTL testing data from this effort will be documented in a separate report to be issued by WERF. This analysis is based on limited testing data and therefore should be considered preliminary. Future refinements are necessary to improve the robustness of the model, including a cross-check of modeled biocrude components with the experimental GCMS data and investigation of equipment costs most appropriate at the smaller scales used here. Environmental sustainability metrics analysis is also needed to understand the broader impact of this technology pathway. The base case scenario for the analysis consists of 10 HTL plants, each processing 100 dry U.S. ton/day (92.4 ton/day on a dry, ash-free basis) of sludge waste and producing 234 barrel per stream day (BPSD) biocrude, feeding into a centralized biocrude upgrading facility that produces 2,020 barrel per standard day of final fuel. This scale was chosen based upon initial wastewater treatment plant data collected by the resource assessment team from the EPA’s Clean Watersheds Needs Survey database (EPA 2015a) and a rough estimate of what the potential sludge availability might be within a 100-mile radius. In addition, we received valuable feedback from the wastewater treatment industry as part of the WERF collaboration that helped form the basis for the selected HTL and upgrading

  9. Impact of gas injection on the apparent viscosity and viscoelastic property of waste activated sewage sludge. (United States)

    Bobade, Veena; Baudez, Jean Christophe; Evans, Geoffery; Eshtiaghi, Nicky


    Gas injection is known to play a major role on the particle size of the sludge, the oxygen transfer rate, as well as the mixing efficiency of membrane bioreactors and aeration basins in the waste water treatment plants. The rheological characteristics of sludge are closely related to the particle size of the sludge floc. However, particle size of sludge floc depends partly on the shear induced in the sludge and partly on physico-chemical nature of the sludge. The objective of this work is to determine the impact of gas injection on both the apparent viscosity and viscoelastic property of sludge. The apparent viscosity of sludge was investigated by two methods: in-situ and after sparging. Viscosity curves obtained by in-situ measurement showed that the apparent viscosity decreases significantly from 4000 Pa s to 10 Pa s at low shear rate range (below 10 s(-1)) with an increase in gas flow rate (0.5LPM to 3LPM); however the after sparging flow curve analysis showed that the reduction in apparent viscosity throughout the shear rate range is negligible to be displayed. Torque and displacement data at low shear rate range revealed that the obtained lower apparent viscosity in the in-situ method is not the material characteristics, but the slippage effect due to a preferred location of the bubbles close to the bob, causing an inconsistent decrease of torque and increase of displacement at low shear rate range. In linear viscoelastic regime, the elastic and viscous modulus of sludge was reduced by 33% & 25%, respectively, due to gas injection because of induced shear. The amount of induced shear measured through two different tests (creep and time sweep) were the same. The impact of this induced shear on sludge structure was also verified by microscopic images.

  10. Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system. (United States)

    Hu, Zhi-Rong; Sötemann, S; Moodley, R; Wentzel, M C; Ekama, G A


    A systematic lab-scale experimental investigation is reported for the external nitrification (EN) biological nutrient removal (BNR) activated sludge (ENBNRAS) system, which is a combined fixed and suspended medium system. The ENBNRAS system was proposed to intensify the treatment capacity of BNR-activated sludge (BNRAS) systems by addressing two difficulties often encountered in practice: (a) the long sludge age for nitrification requirement; and (b) sludge bulking. In the ENBNRAS system, nitrification is transferred from the aerobic reactor in the suspended medium activated sludge system to a fixed medium nitrification system. Thus, the sludge age of the suspended medium activated sludge system can be reduced from 20 to 25 days to 8 to 10 days, resulting in a decrease in reactor volume per ML wastewater treated of about 30%. Furthermore, the aerobic mass fraction can also be reduced from 50% to 60% to 55% (if the anaerobic mass fraction is 15%), and thus complete denitrification in the anoxic reactors becomes possible. Research indicates that both the short sludge age and complete denitrification could ameliorate anoxic aerobic (AA) or low food/microorganism (F/M) ratio filamentous bulking, and hence reduce the surface area of secondary settling tanks or increase the treatment capacity of existing systems. The lab-scale experimental investigations indicate that the ENBNRAS system can obtain: (i) very good chemical oxygen demand (COD) removal, even with an aerobic mass fraction as low as 20%; (ii) high nitrogen removal, even for a wastewater with a high total kjeldahl nitrogen (TKN)/COD ratio, up to 0.14; (iii) adequate settling sludge (diluted sludge volume index [DSVI] <100 mL/g); and (iv) a significant reduction in oxygen demand.

  11. Recovery and stabilization of heavy metal sludge (Cu and Ni) from etching and electroplating plants by electrolysis and sintering

    Institute of Scientific and Technical Information of China (English)

    TSAI LungChang; FANG HungYuan; LIN JianHung; CHEN ChingLiang; TSAI FangChang


    This work dealt with the recovery and stabilization of the sludge with heavy metals (Cu and Ni) pro-duced from etching and electroplating plants. The heavy metals in the sludge were deprived of by acid leaching, followed by precipitation with 28% NH4OH, and finally by electrolysis. In the electrolysis, the recovery percentage and purity were investigated at different electronic currency and temperature. The metal-deprived sludge was stabilized by mixing with glass powder and clay, followed by sintering at high temperature. How the ratio of glass powder to metal-deprived sludge affected final products (sludge bricks) was explored, in terms of specific gravity, absorption capacity, unconfined compressive strength, morphology, the volume shrinkage ratio and burn-up ratio. The volume shrinkage ratio and burn-up ratio of sludge bricks increased with metal-deprived sludge contents. The heavy metal re-maining in sludge bricks was assessed through TCLP (toxicity characteristic leaching procedure) and by the analysis of SEM and EDX. The results from TCLP showed that the contents of leached metals were all below the regulatory criteria. This fact approved the feasibility of our method.

  12. Recovery and stabilization of heavy metal sludge (Cu and Ni) from etching and electroplating plants by electrolysis and sintering

    Institute of Scientific and Technical Information of China (English)

    TSAI; LungChang; TSAI; FangChang


    This work dealt with the recovery and stabilization of the sludge with heavy metals (Cu and Ni) produced from etching and electroplating plants. The heavy metals in the sludge were deprived of by acid leaching, followed by precipitation with 28% NH4OH, and finally by electrolysis. In the electrolysis, the recovery percentage and purity were investigated at different electronic currency and temperature. The metal-deprived sludge was stabilized by mixing with glass powder and clay, followed by sintering at high temperature. How the ratio of glass powder to metal-deprived sludge affected final products (sludge bricks) was explored, in terms of specific gravity, absorption capacity, unconfined compressive strength, morphology, the volume shrinkage ratio and burn-up ratio. The volume shrinkage ratio and burn-up ratio of sludge bricks increased with metal-deprived sludge contents. The heavy metal remaining in sludge bricks was assessed through TCLP (toxicity characteristic leaching procedure) and by the analysis of SEM and EDX. The results from TCLP showed that the contents of leached metals were all below the regulatory criteria. This fact approved the feasibility of our method.

  13. Use of dry sludge from waste water treatment plants as an additive in prefabricated concrete brick

    Directory of Open Access Journals (Sweden)

    Yagüe, A.


    Full Text Available Dry sludge from the Sabadell Water Treatment Plant was used to prepare prefabricated concrete bricks. After characterising the sludge and the manufacturing process used to make the bricks, we define the conditions of addition of the sludges in the manufacture. Reference samples not containing sludge and samples containing 2 % of dry sludge by cement weight were prepared. The variation in density, porosity, absorption coefficient and compressive strength of the bricks with the presence of sludge was determined over time. Leaching of the bricks was determined according to the NEN 7345 standard. In most cases the addition of sludge produces a decrease in porosity and absorption coefficients and an increase in compressive strength, so one could expect these bricks to have greater durability. As regards leaching pollutants in the bricks, they are below the limit of the Dutch NEN standard for construction materials and thus can be classified as inert material.

    El estudio ha consistido en la utilización de lodo seco de origen biológico de la depuradora de aguas residuales de Sabadell (Riu Sec, como adición en la preparación de adoquines de hormigón prefabricado. Después de caracterizar los lodos y el proceso de fabricación de los adoquines que utilizaremos, definimos las condiciones de adición de los lodos en esta fabricación. Se prepararon muestras de referencia, sin adición, y muestras con el 2 % de lodo seco sobrepeso de cemento. Se determinaron cómo variaban en el tiempo, con la presencia de lodos: la densidad, la porosidad y el coeficiente de absorción, y la resistencia mecánica a compresión de los adoquines. También se determinó la lixiviación que estas piezas presentaban de acuerdo a la norma NEN 7345. La adición de lodos produce, en la mayoría de los casos, una disminución de las porosidades y de los coeficientes de absorción y un aumento en las resistencias mecánicas, por lo que cabe esperar una mayor

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

    Directory of Open Access Journals (Sweden)

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


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

  15. Removal performance and mechanism of ibuprofen from water by catalytic ozonation using sludge-corncob activated carbon as catalyst. (United States)

    Wang, Hongjuan; Zhang, Liqiu; Qi, Fei; Wang, Xue; Li, Lu; Feng, Li


    To discover the catalytic activity of sludge-corncob activated carbon in catalytic ozonation of Ibuprofen, the performance of sludge-corncob activated carbon and three selected commercial activated carbons as catalysts in catalytic ozonation was investigated. The observation indicates the degradation rate of Ibuprofen increases significantly in the presence of sludge-corncob activated carbon and the catalytic activity of sludge-corncob activated carbon is much higher than that of the other three commercial activated carbons. Ibuprofen's removal rate follows pseudo-first order kinetics model well. It is also found that the adsorption removal of Ibuprofen by sludge-corncob activated carbon is less than 30% after 40 min. And the removal efficiency of Ibuprofen in the hybrid ozone/sludge-corncob activated carbon system is higher than the sum of sludge-corncob activated carbon adsorption and ozonation alone, which is a supportive evidence for catalytic reaction. In addition, the results of radical scavenger experiments demonstrate that catalytic ozonation of Ibuprofen by sludge-corncob activated carbon follows a hydroxyl radical reaction pathway. During ozonation of Ibuprofen in the presence of activated carbon, ozone could be catalytically decomposed to form hydrogen peroxide, which can promote the formation of hydroxyl radical. The maximum amount of hydrogen peroxide occurs in the presence of sludge-corncob activated carbon, which can explain why sludge-corncob activated carbon has the best catalytic activity among four different activated carbons.

  16. Biodegradation of pharmaceuticals in hospital wastewater by a hybrid biofilm and activated sludge system (Hybas)

    Energy Technology Data Exchange (ETDEWEB)

    Escolà Casas, Mònica [Environmental Science, Aarhus University, Frederiksborgsvej 399, 4000 Roskilde (Denmark); Chhetri, Ravi Kumar [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark); Ooi, Gordon [Environmental Science, Aarhus University, Frederiksborgsvej 399, 4000 Roskilde (Denmark); Hansen, Kamilla M.S. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark); Litty, Klaus [Department of Chemistry and Biotechnology, Danish Technological Institute, Kongsvang Allé 29, 8000 Aarhus C (Denmark); Christensson, Magnus [AnoxKaldnes, Klosterängsvägen 11A, 226 47 Lund (Sweden); Kragelund, Caroline [Department of Chemistry and Biotechnology, Danish Technological Institute, Kongsvang Allé 29, 8000 Aarhus C (Denmark); Andersen, Henrik R. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark); Bester, Kai, E-mail: [Environmental Science, Aarhus University, Frederiksborgsvej 399, 4000 Roskilde (Denmark)


    Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process (hybrid biofilm and activated sludge system (Hybas™)) has been suggested as a possible solution for hospital wastewater treatment. To investigate the potential of such a hybrid system for the removal of pharmaceuticals in hospital wastewater a pilot plant consisting of a series of one activated sludge reactor, two Hybas™ reactors and one moving bed biofilm reactor (MBBR) has been established and adapted during 10 months of continuous operation. After this adaption phase batch and continuous experiments were performed for the determination of degradation of pharmaceuticals. Removal of organic matter and nitrification mainly occurred in the first reactor. Most pharmaceuticals were removed significantly. The removal of pharmaceuticals (including X-ray contrast media, β-blockers, analgesics and antibiotics) was fitted to a single first-order kinetics degradation function, giving degradation rate constants from 0 to 1.49 h{sup −1}, from 0 to 7.78 × 10{sup −1} h{sup −1}, from 0 to 7.86 × 10{sup −1} h{sup −1} and from 0 to 1.07 × 10{sup −1} h{sup −1} for first, second, third and fourth reactors respectively. Generally, the highest removal rate constants were found in the first and third reactors while the lowest were found in the second one. When the removal rate constants were normalized to biomass amount, the last reactor (biofilm only) appeared to have the most effective biomass in respect to removing pharmaceuticals. In the batch experiment, out of 26 compounds, 16 were assessed to degrade more than 20% of the respective pharmaceutical within the Hybas™ train. In the continuous flow experiments, the measured removals were similar to those estimated from the batch experiments, but the concentrations of a few pharmaceuticals appeared to increase

  17. Aerobic degradation of sulfanilic acid using activated sludge. (United States)

    Chen, Gang; Cheng, Ka Yu; Ginige, Maneesha P; Kaksonen, Anna H


    This paper evaluates the aerobic degradation of sulfanilic acid (SA) by an acclimatized activated sludge. The sludge was enriched for over three months with SA (>500 mg/L) as the sole carbon and energy source and dissolved oxygen (DO, >5mg/L) as the primary electron acceptor. Effects of aeration rate (0-1.74 L/min), DO concentration (0-7 mg/L) and initial SA concentration (104-1085 mg/L) on SA biodegradation were quantified. A modified Haldane substrate inhibition model was used to obtain kinetic parameters of SA biodegradation and oxygen uptake rate (OUR). Positive linear correlations were obtained between OUR and SA degradation rate (R(2)≥ 0.91). Over time, the culture consumed more oxygen per SA degraded, signifying a gradual improvement in SA mineralization (mass ratio of O(2): SA at day 30, 60 and 120 were 0.44, 0.51 and 0.78, respectively). The concomitant release of near stoichiometric quantity of sulphate (3.2 mmol SO(4)(2-) released from 3.3 mmol SA) and the high chemical oxygen demand (COD) removal efficacy (97.1%) indicated that the enriched microbial consortia could drive the overall SA oxidation close to a complete mineralization. In contrast to other pure-culture systems, the ammonium released from the SA oxidation was predominately converted into nitrate, revealing the presence of ammonium-oxidizing bacteria (AOB) in the mixed culture. No apparent inhibitory effect of SA on the nitrification was noted. This work also indicates that aerobic SA biodegradation could be monitored by real-time DO measurement.

  18. Carbide sludge management in acetylene producing plants by using vacuum filtration. (United States)

    Ramasamy, Palanisamy; Periathamby, Agamuthu; Ibrahim, Shaliza


    Carbide sludge (10.4-11.5 tonnes day(-1)) is generated from the reaction of calcium carbide (900 kg) and water (6,000 L) in the production of acetylene (2,400 m3), in three selected acetylene manufacturing plants. The sludge (of pH 12.2 and containing Cu, Pb, Fe, Mn, Ni and Zn ions whose concentrations exceed the Department of Environment limits for industrial wastewater) was treated by vacuum filtration as a substitute for the ponding system, which is environmentally less acceptable. A similar system by flocculation was also developed. The filtration system represents an improvement over the ponding method, as shown by a pH of 7 for the clear filtrate; the solid cake, which contains 98% of the metals, can be conveniently disposed at an integrated scheduled waste treatment centre.

  19. Metabolic analysis of the removal of formic acid by unacclimated activated sludge. (United States)

    Viggi, Carolina Cruz; Dionisi, Davide; Miccheli, Alfredo; Valerio, Mariacristina; Majone, Mauro


    This paper investigates the removal of formic acid by unacclimated biomass from a municipal activated sludge wastewater treatment plant. The biomass was initially able to remove formic acid, but its removal rate and Oxygen Uptake Rate (OUR) decreased with time, until formic acid removal stopped before the formic acid had been exhausted. Formaldehyde was removed in a similar way, whereas the same biomass was simultaneously able to grow and store PHAs when acetic acid was used as substrate. Batch tests with glycine and (13)C NMR analysis were performed, showing that unacclimated biomass was not able to synthesize all the metabolic intermediates from formic acid alone. At least glycine needed to be externally supplemented, in order to activate the serine synthesis pathway. A small amount of formic acid removal in the absence of growth was also possible through formaldehyde formation and its further conversion to formalin (1,2-formaldehyde dimer), whereas no PHAs were formed.

  20. [Using Excess Activated Sludge Treated 4-Chlorophenol Contained Waste Water to Cultivate Chlorella vulgaris]. (United States)

    Wang, Lu; Chen, Xiu-rong; Yan, Long; He, Yi-xuan; Shi, Zhen-dong


    Using different rations of sludge extracts and supernate from 4-Chlorophenol (4-CP) simulated wastewater's excess sludge after centrifugation to cultivate the Chlorella vulgaris to achieve the goal of excess sludge utilization together with chlorella cultivating. The experiments were performed in 500 mL flasks with different rations of sludge extracts & BG-11 and supernate & BG-11 in a light growth chamber respectively. Number of algal cells, Chlorophyll, enzyme activity, oil and water total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), toxicity index were investigated. Result showed that the nutrition supplies and toxicity in the excess sludge were removed efficiently via Chlorella vulgaris, the removal rates of TN and TP were at least 40% and 90% respectively; After 10 days cultivation, the density growth of 50% sludge extracts was 20 times higher of the beginning while its chlorophyll content was lower than that of the blank group. Sludge extracts could promote the proliferation of algae, but were not conducive to the synthesis of chlorophyll. The quantity of SOD in per cell showed Chlorella vulgaris gave a positive response via stimulation from toxicant in sludge extracts and supernate. The best time for collecting chlorella vulgaris was the fifth day of cultivation, taking neutral oil accumulation as the evaluating indicator for its utilization combined with the removal of supplies and toxicity.

  1. A new process for efficiently producing methane from waste activated sludge: alkaline pretreatment of sludge followed by treatment of fermentation liquid in an EGSB reactor. (United States)

    Zhang, Dong; Chen, Yinguang; Zhao, Yuxiao; Ye, Zhengxiang


    In the literature the production of methane from waste activated sludge (WAS) was usually conducted in a continuous stirred tank reactor (CSTR) after sludge was pretreated. It was reported in our previous publication that compared with other pretreatment methods the methane production in CSTR could be significantly enhanced when sludge was pretreated by NaOH at pH 10 for 8 days. In order to further improve methane production, this study reported a new process for efficiently producing methane from sludge, that is, sludge was fermented at pH 10 for 8 days, which was adjusted by Ca(OH)(2), and then the fermentation liquid was treated in an expanded granular sludge bed (EGSB) for methane generation. First, for comparing the methane production observed in this study with that reported in the literature, the conventional operational model was applied to produce methane from the pH 10 pretreated sludge, that is, directly using the pH 10 pretreated sludge to produce methane in a CSTR. It was observed that the maximal methane production was only 0.61 m(3)CH(4)/m(3)-reactor/day. Then, the use of fermentation liquid of pH 10 pretreated sludge to produce methane in the reactors of up-flow anaerobic sludge bed (UASB), anaerobic sequencing batch reactor (ASBR) and EGSB was compared. The maximal methane production in UASB, ASBR, and EGSB reached 1.41, 3.01, and 12.43 m(3)CH(4)/m(3)-reactor/day, respectively. Finally, the mechanisms for EGSB exhibiting remarkably higher methane production were investigated by enzyme, adenosine-triphosphate (ATP), scanning electron microscope (SEM) and fluorescence in situ hybridization (FISH) analyses. It was found that the granular sludge in EGSB had the highest conversion efficiency of acetic acid to methane, and the greatest activity of hydrolysis and acidification enzymes and general physiology with much more Methanosarcinaceae.


    Directory of Open Access Journals (Sweden)

    Olena Semenova


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

  3. Utilization of spent activated carbon to enhance the combustion efficiency of organic sludge derived fuel. (United States)

    Chen, Wei-Sheng; Lin, Chang-Wen; Chang, Fang-Chih; Lee, Wen-Jhy; Wu, Jhong-Lin


    This study examines the heating value and combustion efficiency of organic sludge derived fuel, spent activated carbon derived fuel, and derived fuel from a mixture of organic sludge and spent activated carbon. Spent activated carbon was sampled from an air pollution control device of an incinerator and characterized by XRD, XRF, TG/DTA, and SEM. The spent activated carbon was washed with deionized water and solvent (1N sulfuric acid) and then processed by the organic sludge derived fuel manufacturing process. After washing, the salt (chloride) and sulfide content could be reduced to 99% and 97%, respectively; in addition the carbon content and heating value were increased. Different ratios of spent activated carbon have been applied to the organic sludge derived fuel to reduce the NO(x) emission of the combustion.

  4. Structural characterization of metabolites of the X-ray contrast agent iopromide in activated sludge using ion trap mass spectrometry. (United States)

    Pérez, Sandra; Eichhorn, Peter; Celiz, Mary Dawn; Aga, Diana S


    Identification of degradation products of environmental contaminants is a challenging task because not only are they present in very low concentrations but they are also mixed with complex matrixes that interfere with detection. This work illustrates a simple approach using ion trap mass spectrometry combined with H/D-exchange experiments to elucidate the structures of iopromide metabolites formed during biodegradation in activated sludge. Iopromide is an X-ray contrast agent that has been detected frequently in effluents of wastewater treatment plants and in surface waters due to its persistence and high usage. Three metabolites produced by oxidation of the primary alcohols (forming carboxylates) on the side chains of iopromide were identified in a batch reactor with mixed liquor from a conventional activated sludge. Derivatization of the carboxylic acid to form a methyl ester and interpretation of the MS2 data of this derivative aided in the confirmation of the identities of these metabolites. Furthermore, one metabolite formed by dehydroxylation at the two side chains was identified in a batch reactor with mixed liquor from a nitrifying activated sludge. The MS2 fragmentation pattern of iopromide and its metabolites revealed that the iodinated ring remains intact and that minor transformations in the structure occur during biodegradation of iopromide in biological wastewater treatment plants.

  5. Phthalic acid and benzo[a]pyrene in soil-plant-water systems amended with contaminated sewage sludge

    DEFF Research Database (Denmark)

    Mougin, C.; Dappozze, F.; Brault, A.


    We studied the fate of C-14-labelled phthalic acid and benzo[a]pyrene applied to the soil by the way of contaminated sewage sludge in model ecosystems allowing the simultaneous assessment of physicochemical and biological descriptors. Here we show that the mineralisation of phthalic acid is highe......[a]pyrene is recalcitrant to biodegradation whatever the type of soil contamination. We show also that the chemicals present in the sludge are poorly transferred to soil leachates and plant seedlings....

  6. Modelling of the temperature-phased batch anaerobic digestion of raw sludge from an urban wastewater treatment plant


    Riau, Víctor; Rubia, M. Ángeles de la; Pérez, Montserrat; Martín, Antonio; Borja Padilla, Rafael


    The disposal of excess sludge from wastewater treatment plants is a serious problem that needs to be addressed. Temperature-phased anaerobic digestion (TPAD) which combines thermophilic and mesophilic processes in one, brings together the advantages of both systems. The aim of the present work was to develop a simple kinetic model to describe the TPAD of sewage sludge in batch completely stirred tank reactors (CSTRs) and to determine the kinetic parameters of both thermophilic and mesophilic ...

  7. Coagulant recovery from water treatment plant sludge and reuse in post-treatment of UASB reactor effluent treating municipal wastewater. (United States)

    Nair, Abhilash T; Ahammed, M Mansoor


    In the present study, feasibility of recovering the coagulant from water treatment plant sludge with sulphuric acid and reusing it in post-treatment of upflow anaerobic sludge blanket (UASB) reactor effluent treating municipal wastewater were studied. The optimum conditions for coagulant recovery from water treatment plant sludge were investigated using response surface methodology (RSM). Sludge obtained from plants that use polyaluminium chloride (PACl) and alum coagulant was utilised for the study. Effect of three variables, pH, solid content and mixing time was studied using a Box-Behnken statistical experimental design. RSM model was developed based on the experimental aluminium recovery, and the response plots were developed. Results of the study showed significant effects of all the three variables and their interactions in the recovery process. The optimum aluminium recovery of 73.26 and 62.73 % from PACl sludge and alum sludge, respectively, was obtained at pH of 2.0, solid content of 0.5 % and mixing time of 30 min. The recovered coagulant solution had elevated concentrations of certain metals and chemical oxygen demand (COD) which raised concern about its reuse potential in water treatment. Hence, the coagulant recovered from PACl sludge was reused as coagulant for post-treatment of UASB reactor effluent treating municipal wastewater. The recovered coagulant gave 71 % COD, 80 % turbidity, 89 % phosphate, 77 % suspended solids and 99.5 % total coliform removal at 25 mg Al/L. Fresh PACl also gave similar performance but at higher dose of 40 mg Al/L. The results suggest that coagulant can be recovered from water treatment plant sludge and can be used to treat UASB reactor effluent treating municipal wastewater which can reduce the consumption of fresh coagulant in wastewater treatment.

  8. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate (United States)

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo


    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d‑1) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery.



    Agnieszka Tomska


    Due to the increasing consumption of pharmaceuticals for the treatment of humans and animals as well as inadequate procedures for the disposal of pharmaceuticals into environmental, pollution caused by them is increasing. Generally these substances are introduced to the wastewater treatment plant with municipal wastewater. They are often resistant to biodegradation and can cause to the disruption in biological wastewater treatment processes. Traditional water treatment plants are not designed...

  10. Bioremediation of petroleum hydrocarbons in soil: Activated sludge treatability study

    Energy Technology Data Exchange (ETDEWEB)

    Rue-Van Es, J.E. La.


    Batch activated sludge treatability studies utilizing petroleum hydrocarbon contaminated soils (diesel oil and leaded gasoline) were conducted to determine: initial indigenous biological activity in hydrocarbon-contaminated soils; limiting factors of microbiological growth by investigating nutrient addition, chemical emulsifiers, and co-substrate; acclimation of indigenous population of microorganisms to utilize hydrocarbons as sole carbon source; and temperature effects. Soil samples were taken from three different contaminated sites and sequencing batch reactors were run. Substrate (diesel fuel) and nutrient were added as determined by laboratory analysis of orthophosphate, ammonia nitrogen, chemical oxygen demand, and total organic carbon. Substrate was made available to the bacterial mass by experimenting with four different chemical emulsifiers. Indigenous microorganisms capable of biotransforming hydrocarbons seem to be present in all the contaminated soil samples received from all sites. Microscopic analysis revealed no visible activity at the beginning of the study and presence of flagellated protozoa, paramecium, rotifers, and nematodes at the end of the year. Nutrient requirements and the limiting factors in microorganism growth were determined for each site. An emulsifier was initially necessary to make the substrate available to the microbial population. Decreases in removal were found with lowered temperature. Removal efficiencies ranged from 50-90%. 95 refs., 11 figs., 13 tabs.

  11. Chemistry of flyash scrubber sludge components in plant-soil-water systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.


    Flyash scrubber sludge (FASS) is a by-product from coal combustion at power plants. Land application and burial beneath wetlands have been suggested as more cost efficient disposal methods than burial in old mines. The FASS from the Associated Electric Power Plant at Thomas Hill, MO was added, 2.5 or 5.0% FASS by weight, to an acidic topsoil. FASS increased soil pH and salt level, and increased growth of alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.) and tall fescue (Festuca aroundinacea L.). Concentrations of Al, Ba, Ca, Cd, Cu, Fe, K, Mg, Ni, P, Si, Sr, Ti, and Zn in plant tissues were either unaffected or reduced due to FASS addition. The concentrations of B, Cl, Mo, Mn, and S were higher in tissues of plants grown on FASS treated than untreated soil. Boron content limited the amount of FASS that could be applied to soil.

  12. Inhibitory effect of ammonia nitrogen on specific methanogenic activity of anaerobic granular sludge

    Institute of Scientific and Technical Information of China (English)


    A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed(UASB) and expanded granular sludge bed(EGSB) reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50% inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia nitrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.

  13. Removal of Cu(II from Aqueous Solutions using Dried Activated Sludge and Dried Activated Nano-Sludge: Adsorption on a Fixed-Bed Column

    Directory of Open Access Journals (Sweden)

    Zahra Ahmari


    Full Text Available In the present time study,dried activated sludge(DAS and dried activated nano sludge(DANS was used for the removal of Cu(II from aqueous solution in a fixed-bed reactor. The effect of important parameters including the flow rate and bed height were examined. Dried activated nano sludge column regeneration using 1 M concentration of HNO3 has been studied.The Thomas model was used for the mathematical description of the adsorption of Copper at different flow rate and various bed height to determine parameters of the column suitable for process design. Both exhaustion time and breakthrough time increased with increasing bed height, while the adsorption bed capacity decreased as the flow rate increased.

  14. Inhibition of total oxygen uptake by silica nanoparticles in activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Sibag, Mark [Department of Environment and Energy, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Choi, Byeong-Gyu [School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-ro, Sungbuk-ku, Seoul 136-701 (Korea, Republic of); Suh, Changwon [Energy Lab, Environment Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Lee, Kwan Hyung; Lee, Jae Woo [Department of Environmental Engineering and Program in Environmental Technology and Policy, Korea University, Sejong 339-700 (Korea, Republic of); Maeng, Sung Kyu [Department of Civil and Environmental Engineering, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Cho, Jinwoo, E-mail: [Department of Environment and Energy, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of)


    Highlights: • Silica nanoparticles (SNP) inhibit total oxygen uptake in activated sludge. • Relatively smaller SNP are inhibitorier than larger SNP. • SNP alters C15:0, C16:0 and C18:0 in activated sludge fatty acid methyl ester profile. - Abstract: Nanoparticle toxicity to biological activities in activated sludge is largely unknown. Among the widely used nanoparticles, silica nanoparticles (SNP) have a limited number of studies associated with inhibition to the activated sludge process (ASP). We demonstrated SNP inhibition of activated sludge respiration through oxygen uptake rate (OUR) measurement. Based on the percentage inhibition of total oxygen consumption (I{sub T}), we observed that smaller SNPs (12 nm, I{sub T} = 33 ± 3%; 151 nm, I{sub T} = 23 ± 2%) were stronger inhibitors than larger SNPs (442 and 683 nm, I{sub T} = 5 ± 1%). Transmission electron micrographs showed that some of the SNPs were adsorbed on and/or apparently embedded somewhere in the microbial cell membrane. Whether SNPs are directly associated with the inhibition of total oxygen uptake warrants further studies. However, it is clear that SNPs statistically significantly altered the composition of microbial membrane lipids, which was more clearly described by principal component analysis and weighted Euclidian distance (PCA-ED) of the fatty acid methyl ester (FAME) data. This study suggests that SNPs potentially affect the biological activity in activated sludge through the inhibition of total oxygen uptake.

  15. Batch system for study of Cr(VI) Bio sorption by dried waste activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Farzadkia, M.; Gholami, M.; Darvishi Cheshmeh Soltani, R.; Yaghmaeian, K.; Shams Khorramabadi, G.


    Activated sludge from wastewater treatment systems contains both bacteria and protozoa. The cell wall of bacteria essentially consists of various compounds, such as carboxyl, acidic polysaccharides,lipids, amino acids and other components. (Author)

  16. Effects of activated sludge flocs and pellets seeds on aerobic granule properties

    Institute of Scientific and Technical Information of China (English)

    Huacheng Xu; Pinjing He; Guanzhao Wang; Liming Shao


    Aerobic granules seeded with activated sludge fiocs and pellets (obtained from activated sludge flocs) were cultivated in two sequencing batch reactors and their characteristics were compared.Compared with granules seeded with activated sludge flocs, those seeded with pellets had shorter start-up time, larger diameter, better chemical oxygen demand removal efficiency, and higher hydrophobicity, suspended solid concentration, and Mg2+ content.The different inocula led the granule surface with different microbial morphologies, but did not result in different distribution patterns of extracellular polymeric substances and cells.The anaerobic bacterium Anoxybacillus sp.was detected in the granules seeded with pellets.These results highlighted the advantage of pellet over activated sludge floc as the seed for aerobic granulation and wastewater treatment.

  17. Comparison of bacterial communities of conventional and A-stage activated sludge systems

    NARCIS (Netherlands)

    Gonzalez-Martinez, A.; Rodriguez-Sanchez, A.; Lotti, T.; Garcia-Ruiz, M.J.; Gonzalez-Lopez, J.; Van Loosdrecht, M.C.M.


    The bacterial community structure of 10 different wastewater treatment systems and their influents has been investigated through pyrosequencing, yielding a total of 283486 reads. These bioreactors had different technological configurations: conventional activated sludge (CAS) systems and very highly

  18. Factors influencing sorption of ciprofloxacin onto activated sludge: Experimental assessment and modelling implications

    DEFF Research Database (Denmark)

    Polesel, Fabio; Lehnberg, Kai; Dott, Wolfgang;


    Many of the pharmaceuticals and personal care products occurring in municipal sewage are ionizing substances, and their partitioning behaviour is affected by ionic interactions with solid matrices. In activated sludge systems, such interactions have currently not been adequately understood...

  19. The impact of zinc oxide nanoparticles on the bacterial microbiome of activated sludge systems (United States)

    Meli, K.; Kamika, I.; Keshri, J.; Momba, M. N. B.


    The expected growth in nanomaterial applications could result in increased amounts of nanoparticles entering municipal sewer systems, eventually ending up in wastewater treatment plants and therefore negatively affecting microbial populations and biological nutrient removal. The aim of this study was to ascertain the impact of zinc oxide nanoparticles (nZnO) on the bacterial microbiome of an activated sludge system. A metagenomic approach combined with the latest generation Illumina MiSeq platform and RDP pipeline tools were used to identify and classify the bacterial microbiome of the sludge. Results revealed a drastic decrease in the number of operational taxonomic units (OTUs) from 27 737 recovered in the nZnO-free sample to 23 743, 17 733, and 13 324 OTUs in wastewater samples exposed to various concentrations of nZnO (5, 10 and 100 mg/L nZnO, respectively). These represented 12 phyla, 21 classes, 30 orders, 54 families and 51 genera, completely identified at each taxonomic level in the control samples; 7-15-25-28-20 for wastewater samples exposed to 5 mg/L nZnO; 9-15-24-31-23 for those exposed to 10 mg/L and 7-11-19-26-17 for those exposed 100 mg/L nZnO. A large number of sequences could not be assigned to specific taxa, suggesting a possibility of novel species to be discovered.

  20. Wastewater treatment--adsorption of organic micropollutants on activated HTC-carbon derived from sewage sludge. (United States)

    Kirschhöfer, Frank; Sahin, Olga; Becker, Gero C; Meffert, Florian; Nusser, Michael; Anderer, Gilbert; Kusche, Stepan; Klaeusli, Thomas; Kruse, Andrea; Brenner-Weiss, Gerald


    Organic micropollutants (MPs), in particular xenobiotics and their transformation products, have been detected in the aquatic environment and the main sources of these MPs are wastewater treatment plants. Therefore, an additional cleaning step is necessary. The use of activated carbon (AC) is one approach to providing this additional cleaning. Industrial AC derived from different carbonaceous materials is predominantly produced in low-income countries by polluting processes. In contrast, AC derived from sewage sludge by hydrothermal carbonization (HTC) is a regional and sustainable alternative, based on waste material. Our experiments demonstrate that the HTC-AC from sewage sludge was able to remove most of the applied MPs. In fact more than 50% of sulfamethoxazole, diclofenac and bezafibrate were removed from artificial water samples. With the same approach carbamazepine was eliminated to nearly 70% and atrazine more than 80%. In addition a pre-treated (phosphorus-reduced) HTC-AC was able to eliminate 80% of carbamazepine and diclofenac. Atrazine, sulfamethoxazole and bezafibrate were removed to more than 90%. Experiments using real wastewater samples with high organic content (11.1 g m(-3)) succeeded in proving the adsorption capability of phosphorus-reduced HTC-AC.

  1. Activated sludge is a potential source for production of biodegradable plastics from wastewater. (United States)

    Khardenavis, A; Guha, P K; Kumar, M S; Mudliar, S N; Chakrabarti, T


    Increased utilization of synthetic plastics caused severe environmental pollution due to their non-biodegradable nature. In the search for environmentally friendly materials to substitute for conventional plastics, different biodegradable plastics have been developed by microbial fermentations. However, limitations of these materials still exist due to high cost. This study aims at minimization of cost for the production of biodegradable plastics P(3HB) and minimization of environmental pollution. The waste biological sludge generated at wastewater treatment plants is used for the production of P(3HB) and wastewater is used as carbon source. Activated sludge was induced by controlling the carbon: nitrogen ratio to accumulate storage polymer. Initially polymer accumulation was studied by using different carbon and nitrogen sources. Maximum accumulation of polymer was observed with carbon source acetic acid and diammonium hydrogen phosphate (DAHP) as nitrogen source. Further studies were carried out to optimize the carbon: nitrogen ratios using acetic acid and DAHP. A maximum of 65.84% (w/w) P(3HB) production was obtained at C/N ratio of 50 within 96 hours of incubation.

  2. Lab-scale experimental strategy for determining micropollutant partition coefficient and biodegradation constants in activated sludge. (United States)

    Pomiès, M; Choubert, J M; Wisniewski, C; Miège, C; Budzinski, H; Coquery, M


    The nitrifying/denitrifying activated sludge process removes several micropollutants from wastewater by sorption onto sludge and/or biodegradation. The objective of this paper is to propose and evaluate a lab-scale experimental strategy for the determination of partition coefficient and biodegradation constant for micropollutant with an objective of modelling their removal. Four pharmaceutical compounds (ibuprofen, atenolol, diclofenac and fluoxetine) covering a wide hydrophobicity range (log Kow from 0.16 to 4.51) were chosen. Dissolved and particulate concentrations were monitored for 4 days, inside two reactors working under aerobic and anoxic conditions, and under different substrate feed conditions (biodegradable carbon and nitrogen). We determined the mechanisms responsible for the removal of the target compounds: (i) ibuprofen was biodegraded, mainly under aerobic conditions by cometabolism with biodegradable carbon, whereas anoxic conditions suppressed biodegradation; (ii) atenolol was biodegraded under both aerobic and anoxic conditions (with a higher biodegradation rate under aerobic conditions), and cometabolism with biodegradable carbon was the main mechanism; (iii) diclofenac and fluoxetine were removed by sorption only. Finally, the abilities of our strategy were evaluated by testing the suitability of the parameters for simulating effluent concentrations and removal efficiency at a full-scale plant.

  3. Interference sources in ATP bioluminescence assay of silica nanoparticle toxicity to activated sludge. (United States)

    Sibag, Mark; Kim, Seung Hwan; Kim, Choah; Kim, Hee Jun; Cho, Jinwoo


    ATP measurement provides an overview of the general state of microbial activity, and thus it has proven useful for the evaluation of nanoparticle toxicity in activated sludge. ATP bioluminescence assay, however, is susceptible to interference by the components of activated sludge other than biomass. This paper presents the interference identified specific to the use of this assay after activated sludge respiration inhibition test of silica nanoparticles (OECD 209). We observed a high degree of interference (90%) in the presence of 100 mg/L silica nanoparticles and a low level of ATP being measured (0.01 μM); and 30% interference by the synthetic medium regardless of silica nanoparticle concentration and ATP level in the samples. ATP measurement in activated sludge with different MLSS concentrations revealed interference of high biomass content. In conclusion, silica nanoparticles, synthetic medium and activated sludge samples themselves interfere with ATP bioluminescence; this will need to be considered in the evaluation of silica nanoparticle toxicity to activated sludge when this type of assay is used.

  4. 焦化废水处理厂活性污泥对硫氰化物的降解机制%Biodegradation mechanism of thiocyanate by activated sludge from coking wastewater treatment plant

    Institute of Scientific and Technical Information of China (English)

    张玉秀; 尹莉; 李海波; 蒙小俊; 盛宇星; 曹宏斌


    The influent and effluent qualities of A/A/O in coking wastewater biological treatment system and degradation mechanism of thiocyanate ( SCN-) by aerobic sludge were studied using the spectrophotometry and ion chromatography. The results showed that SCN-was mainly removed in the aerobic unit of A/A/O process. The degradation kinetics of SCN-in the activated sludge followed the Michaelis-Menten equation at room temperature ( 25 ℃) , and the kinetic parameters Vm ax and Km were 11.15 mg SCN-·( g-1 MLSS)·h-1 and 44.96 mg·L-1 , respectively. The degradation rate of SCN-was reduced significantly at 15 ℃. SCN- of 92.62 mg·L-1 was degraded completely within 24 h at 15 ℃. Intermediate products of NH3-N, NO-2 and S2- were produced with SCN- degradation, and were ultimately transformed to NO-3 and SO2-4 , respectively. The transformation rates of N and S element were 94.32% and 99.08%, respectively, which were in line with the law of mass balance, indicating N and S elements of SCN-could be completely transformed to NO-3 and SO2-4 in the aerobic tank. These results provide useful information for understanding the function of aerobic tank and improving removal of SCN- in coking wastewater.%用分光光度法和离子色谱法,研究了A/A/O工艺焦化废水处理厂的进出水质和活性污泥对硫氰化物( SCN-)的降解机制.研究结果表明,SCN-主要在A/A/O工艺的好氧单元中降解去除;在常温( 25 ℃)下活性污泥对SCN-降解的动力学过程符合米氏方程,Vmax为11.15 mg SCN-·(g-1 MLSS)·h-1,Km为44.96 mg·L-1;15 ℃低温显著降低SCN-的降解速率;在15 ℃下,92.62 mg·L-1 SCN-能在24 h内完全降解,其中的N和S元素相应地生成了NH3、NO-2 和S2-等中间代谢产物,并最终转化为产物NO-3 和SO2-4 ;N和S元素的转化率分别为94.32%和99.08%,基本符合物料守恒定律,说明SCN-中N和S元素在好氧池中可以彻底降解转化NO-3 和SO2-4 .这些结果对于了解好氧池的功能和提高焦

  5. Activated-sludge nitrification in the presence of linear and branched-chain alkyl benzene sulfonates. (United States)

    Baillod, C R; Boyle, W C


    The effects of biodegradable linear alkyl benzene sulfonate and branched-chain alkyl benzene sulfonate detergents on activated-sludge nitrification were investigated by administering a synthetic waste containing up to 23 mg of each detergent per liter to eight bench-scale, batch, activated-sludge units. It was found that both detergents tended to promote complete oxidation of ammonia to nitrate, whereas control units produced approximately equal amounts of nitrite and nitrate. Various hypotheses are offered to explain the phenomenon.

  6. Aerobic thermophilic treatment of sewage sludge at pilot plant scale. 2. Technical solutions and process design. (United States)

    Ponti, C; Sonnleitner, B; Fiechter, A


    The performance of the ATS process depends essentially on the oxygen transfer efficiency. Improvement of the mass transfer capacity of a bioreactor allowed to reduce the incubation time necessary to attain sludge stabilization. It is important to use equipment with a high aeration efficiency such as an injector aeration system. The ratio between the total oxygen consumption and the organic matter degradation (delta COD) ranged between 0.4 and 0.8 in the pilot plant, whereas 1.23 was found in completely mixed bioreactors (Bomio, 1990). No significant improvement of the bacterial degradation efficiency was attained with a specific power input exceeding 6-8 kW m-3. A mean residence time of less than 1 d allowed organic matter removals up to 40% with specific power consumption of 10 kWh kg-1 COD oxidized. The sludge hygienization is one of the objectives and benefits of the thermophilic treatment: not only temperature but also the total solids content were important factors affecting inactivation of pathogens. The inactivation rate was promoted by the increase of temperature, while the residual colony forming units decreased with reducing the total solids content of sewage sludge. It is concluded that continuous operation mode would not affect the quality of the hygienization but could display the high degradation potential of the aerobic system.


    Institute of Scientific and Technical Information of China (English)

    山丹; 王金生; 李云生; 王晨; 吴悦颖


    Standardization and technical innovation is the basis for scientific reduction of total emission. This paper deals with the case of a sewage processing plant, to examine water composition, processing technology, treatment principles at different stages of the production line, main equipments, key operating parameters, for the entire processing procedure. The paper summarizes major accounting and auditing points for an urban sewage processing plant using activated sludge processing. Theoretical foundation and basic data support for the realization of scientific urban sewage treatment plants and total emission reduction were provided.%以某污水处理厂为例,在对来水构成、处理工艺以及各个工段的处理原理、主体设备、关键运行参数进行全过程分析的基础上,总结提炼了城镇污水处理厂活性污泥处理工艺的核查要点,为实现科学化城镇污水处理厂总量减排核查工作提供了理论依据和基本数据支持.

  8. High-rate activated sludge system for carbon management--Evaluation of crucial process mechanisms and design parameters. (United States)

    Jimenez, Jose; Miller, Mark; Bott, Charles; Murthy, Sudhir; De Clippeleir, Haydee; Wett, Bernhard


    The high-rate activated sludge (HRAS) process is a technology suitable for the removal and redirection of organics from wastewater to energy generating processes in an efficient manner. A HRAS pilot plant was operated under controlled conditions resulting in concentrating the influent particulate, colloidal, and soluble COD to a waste solids stream with minimal energy input by maximizing sludge production, bacterial storage, and bioflocculation. The impact of important process parameters such as solids retention time (SRT), hydraulic residence time (HRT) and dissolved oxygen (DO) levels on the performance of a HRAS system was demonstrated in a pilot study. The results showed that maximum removal efficiencies of soluble COD were reached at a DO > 0.3 mg O2/L, SRT > 0.5 days and HRT > 15 min which indicates that minimizing the oxidation of the soluble COD in the high-rate activated sludge process is difficult. The study of DO, SRT and HRT exhibited high degree of impact on the colloidal and particulate COD removal. Thus, more attention should be focused on controlling the removal of these COD fractions. Colloidal COD removal plateaued at a DO > 0.7 mg O2/L, SRT > 1.5 days and HRT > 30 min, similar to particulate COD removal. Concurrent increase in extracellular polymers (EPS) production in the reactor and the association of particulate and colloidal material into sludge flocs (bioflocculation) indicated carbon capture by biomass. The SRT impacted the overall mass and energy balance of the high-rate process indicating that at low SRT conditions, lower COD mineralization or loss of COD content occurred. In addition, the lower SRT conditions resulted in higher sludge yields and higher COD content in the WAS.

  9. Effect of humic acid in leachate on specific methanogenic activity of anaerobic granular sludge. (United States)

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


    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.

  10. 谈污水处理厂污泥处理系统%Discussion on sludge treatment system of sewage treatment plant

    Institute of Scientific and Technical Information of China (English)



    This article mainly discusses sludge treatment system of sewage treatment plant,describes sludge discharge,sludge thickening,sludge conditioning,sludge mechanical dewatering,and sludge treatment and other aspects,so as to control sludge production and to guarantee the water quality of sewage treatment plant.%主要论述了污水处理厂的污泥处理系统,从污泥处理的各个环节,包括排泥、污泥浓缩、污泥调理、污泥机械脱水和污泥处置等几方面进行了阐述,行之有效的控制污泥生产,以保证污水处理厂水质合格达标。

  11. Biofac, a microbiological multimedia tool to perform the analysis of activated sludge; Biofac, una herramienta de autoformacion microbiologica para el analisis del fango activo

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer Torregrosa, C.; Llopis Nicolau, A.; Claramonte Santarrufina, J.; Alonso Hernandez, S.


    The composition and structure of the macrobiotic that is part of the active sludge, its temporal evolution, and the analysis of the macroscopic and microscopic characteristics of it are a source of information of great help in making decisions for plant operators. Lack of training and access to specific information linked to the missing standardization of analysis processes hinder the implementation and interpretation of them. Using a multimedia tool in DVD, Facsa has developed the Biofac, an application in which it is documented and illustrated the most relevant aspects that allow the user to perform the analysis of activated sludge. (Author)

  12. Fate of Triclosan in activated sludge treatment - bridging the missing gap

    DEFF Research Database (Denmark)

    Bester, Kai; Chen, Xijuan; Furgal, Karolina;

    Triclosan is a bactericide used in increasing shelflife of cosmetics, improving hygenics in sportswear as well as in toothpaste and in mouth wash. More than 350 tons Triclosan is annually produced in Europe, and most of it finally is emitted into wastewater at the end of its life cycle. Therefore......, the fate of this compound in wastewater treatment is of high interest, especially as triclosan has detrimental effects on, e.g., micro-algae at very low concentrations.  It has been demonstrated, that the elimination of triclosan is very effective in wastewater treatment with eliminination rates > 90......%. However, a persistent transformation product (triclosan-methyl) is beeing formed in the activated sludge treatment process. In contrast to other studies, mass balances on wastewater treatment plants show that the fate of more than 50% of the incoming triclosan remains unknown. In this study we...

  13. An activated sludge model for xenobiotic organic micro-pollutants (ASM-X)

    DEFF Research Database (Denmark)

    Plósz, Benedek; Lehnberg, K.; Dott, W.


    deteriorate; thereby hindering the effluent quality of secondary treatment step, and thereby increasing the XOM mass load on the tertiary treatment step. Besides the impact of different redox conditions, divalent iron-salt dosing used for enhanced phosphorus removal and pH have been identified as potential...... the XOMs content of pre-clarified municipal sewage. Evaluation of the model structure is carried out in dynamic simulations using data obtained in samples taken in a measuring campaign in a full-scale activated sludge wastewater treatment plant (WWTP). Our results suggest that the sorption....... We additionally show that the impact of Fe-salt added can vary under aerobic, anoxic and anaerobic conditions, and that the presence of nitrate can significantly influence CIP partitioning under aerobic conditions. The possible depletion of nitrate in the pre-anoxic effluent can additionally...

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

    DEFF Research Database (Denmark)

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


    Removal of five acidic pharmaceuticals (ibuprofen, ketoprofen, naproxen, diclofenac and clofibric acid) by activated sludge from five municipal activated sludge treatment processes, with various sludge ages and nitrification capacities, was assessed through batch experiments. The increase...... in aerobic sludge age from 1-3 to 7 days seemed to be critical for the removal of naproxen and ketoprofen, with markedly higher rates of removal at sludge ages of 7 days or more. No removal was shown for diclofenac and clofibric acid, while high rates were observed for ibuprofen in all investigated sludges....... Parallel examinations of activated sludge batches with and without allylthiourea (12 mg/L), an inhibitor of ammonia monooxygenase, showed minor to moderate influence on the removal rates of ketoprofen and naproxen. These results suggest that the removal rates of biodegradable pharmaceuticals in municipal...

  15. Digestion of high rate activated sludge coupled to biochar formation for soil improvement in the tropics. (United States)

    Nansubuga, Irene; Banadda, Noble; Ronsse, Frederik; Verstraete, Willy; Rabaey, Korneel


    High rate activated sludge (HRAS) is well-biodegradable sludge enabling energy neutrality of wastewater treatment plants via anaerobic digestion. However, even through successful digestion a notable residue still remains. Here we investigated whether this residue can be converted to biochar, for its use as a fertilizer or as a solid fuel, and assessed its characteristics and overall process efficiency. In a first phase, HRAS was anaerobicaly digested under mesophilic conditions at a sludge retention time of 20 days. HRAS digested well (57.9 ± 6.2% VS degradation) producing on average 0.23 ± 0.04 L CH4 per gram VS fed. The digestate particulates were partially air-dried to mimic conditions used in developing countries, and subsequently converted to biochar by fixed-bed slow pyrolysis at a residence time of 15 min and at highest heating temperatures (HHT) of 300 °C, 400 °C and 600 °C. Subsequently, the produced chars were characterized by proximate analysis, CHN-elemental analysis, pH in solution and bomb calorimetry for higher heating value. The yield and volatile matter decreased with increasing HHT while ash content and fixed carbon increased with increasing HHT. The produced biochar showed properties optimal towards soil amendment when produced at a temperature of 600 °C with values of 5.91 wt%, 23.75 wt%, 70.35% on dry basis (db) and 0.44 for volatile matter, fixed carbon, ash content and H/C ratio, respectively. With regard to its use for energy purposes, the biochar represented a lower calorific value than the dried HRAS digestate likely due to high ash content. Based on these findings, it can be concluded that anaerobic digestion of HRAS and its subsequent biochar formation at HHT of 600 °C represents an attractive route for sludge management in tropic settings like in Uganda, coupling carbon capture to energy generation, carbon sequestration and nutrient recovery.

  16. Ultrasonic waste activated sludge disintegration for recovering multiple nutrients for biofuel production. (United States)

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Qilin; Ding, Jie; Ren, Nan-Qi


    Waste activated sludge is a valuable resource containing multiple nutrients, but is currently treated and disposed of as an important source of pollution. In this work, waste activated sludge after ultrasound pretreatment was reused as multiple nutrients for biofuel production. The nutrients trapped in sludge floc were transferred into liquid medium by ultrasonic disintegration during first 30 min, while further increase of pretreatment time only resulted in slight increase of nutrients release. Hydrogen production by Ethanoligenens harbinense B49 from glucose significantly increased with the concentration of ultrasonic sludge, and reached maximum yield of 1.97 mol H2/mol glucose at sludge concentration of 7.75 g volatile suspended solids/l. Without addition of any other chemicals, waste molasses rich in carbohydrate was efficiently turned into hydrogen with yield of 189.34 ml H2/g total sugar by E. harbinense B49 using ultrasonic sludge as nutrients. The results also showed that hydrogen production using pretreated sludge as multiple nutrients was higher than those using standard nutrients. Acetic acid produced by E. harbinense B49 together with the residual nutrients in the liquid medium were further converted into hydrogen (271.36 ml H2/g total sugar) by Rhodopseudomonas faecalis RLD-53 through photo fermentation, while ethanol was the sole end product with yield of 220.26 mg/g total sugar. Thus, pretreated sludge was an efficient nutrients source for biofuel production, which could replace the standard nutrients. This research provided a novel strategy to achieve environmental friendly sludge disposal and simultaneous efficient biofuel recovery from organic waste.

  17. [Study on dewatering of activated sludge under applied electric field]. (United States)

    Ji, Xue-Yuan; Wang, Yi-Li; Feng, Jing


    For an electro-dewatering process of activated sludge (AS), the effect of pH and conductivity of AS, flocculation conditioning and operation factors of horizontal electric field (voltage magnitude, method of applying electric field and distance between plates) were investigated, and the corresponding optimum electro-dewatering conditions were also obtained. The results showed that the best electro-dewatering effect was achieved for AS without change of its pH value (6.93) and conductivity (1.46 mS x cm(-1)). CPAM conditioning could lead to the increase of 30%-40% in the dewatering rate and accelerate the dewatering process, whereas a slight increase in the electro-dewatering rate. The electro-dewatering rate for conditioned AS reached 83.12% during an electric field applied period of 60 minutes, while this rate for original AS could be 75.31% even the electric field applied period extended to 120 minutes. The delay of applying the electric field had an inhibition effect on the AS electro-dewatering rate. Moreover, the optimum conditions for AS electro-dewatering were followed: CPAM dose of 9 g x kg(-1), electric field strength of 600 V x m(-1), distance between the two plates of 40 mm, dehydration time of 60 minutes. Under above optimum conditions the AS electro-dewatering rate could approach to 85.33% and the moisture content in AS decreased from 99.30% to 95.15% accordingly.

  18. Modeling organic nitrogen conversions in activated sludge bioreactors. (United States)

    Makinia, Jacek; Pagilla, Krishna; Czerwionka, Krzysztof; Stensel, H David


    For biological nutrient removal (BNR) systems designed to maximize nitrogen removal, the effluent total nitrogen (TN) concentration may range from 2.0 to 4.0 g N/m(3) with about 25-50% in the form of organic nitrogen (ON). In this study, current approaches to modeling organic N conversions (separate processes vs. constant contents of organic fractions) were compared. A new conceptual model of ON conversions was developed and combined with Activated Sludge Model No. 2d (ASM2d). The model addresses a new insight into the processes of ammonification, biomass decay and hydrolysis of particulate and colloidal ON (PON and CON, respectively). Three major ON fractions incorporated are defined as dissolved (DON) (model parameter set, the behaviors of both inorganic N forms (NH4-N, NOX-N) and ON forms (DON, CON) in the batch experiments were predicted. The challenges to accurately simulate and predict effluent ON levels from BNR systems are due to analytical methods of direct ON measurement (replacing TKN) and lack of large enough database (in-process measurements, dynamic variations of the ON concentrations) which can be used to determine parameter value ranges.

  19. Drivers of Plant-Availability of Phosphorus from Thermally Conditioned Sewage Sludge as Assessed by Isotopic Labeling (United States)

    Andriamananjara, Andry; Rabeharisoa, Lilia; Prud’homme, Loïc; Morel, Christian


    Urban sewage sludge is a potential source of phosphorus (P) for agriculture and represents an alternative way to recycle P as fertilizer. However, the use of thermally conditioned sewage sludge (TCSS) required an accurate assessment of its value as P-fertilizer. This work aimed at assessing the plant-availability of P from TCSS. Uptake of P by a mixture of ryegrass and fescue from TCSS and triple super phosphate (TSP) fertilizers was studied using 32P-labeling technique in a greenhouse experiment. Phosphorus was applied at the rate of 50 mg P kg−1.We also conducted incubation experiments considering the same treatments to assess soil microbial respiration. Applications of TCSS and TSP increased plant P uptake that is related to the root P acquisition. The P taken up by plant from soil plant-available P was lower for control compared to TSP or TCSS that was attributed to the increase of root interception of soil P. The contribution of TSP to ryegrass nutrition (Pdff%) was 55% with 22% of the applied P which was taken up by plants (CPU%). The Pdff value for TCSS was 56% with 14% of fertilizer P recovery (CPU%). Shoot biomass and total P uptake from TCSS were lower than those from TSP. As a result, the agronomic effectiveness of TCSS calculated from Pdff value (in comparison with TSP treatment) was 102%, while the AE of TCSS estimated from CPU value (in % TSP) was 64%, which is attributed to microbial activity stimulation inducing P immobilization onto soil constituents and microbial biomass during plant growth. The high C/N ratio of TCSS stimulated soil microbial biomass that competes with plant roots to acquire nutrients, such as P. As a consequence, the P taken up from either native soil or TCSS decreased in similar proportions. The AE value calculated with Pdff% took into account these interactions between soil, plant, and microbial biomass, and is less dependent on operational conditions than the AE value calculated with %Precovery. PMID:27379240

  20. The influence of hydrolysis induced biopolymers from recycled aerobic sludge on specific methanogenic activity and sludge filterability in an anaerobic membrane bioreactor. (United States)

    Buntner, D; Spanjers, H; van Lier, J B


    The objective of the present study was to evaluate the impact of excess aerobic sludge on the specific methanogenic activity (SMA), in order to establish the maximum allowable aerobic sludge loading. In batch tests, different ratios of aerobic sludge to anaerobic inoculum were used, i.e. 0.03, 0.05, 0.10 and 0.15, showing that low ratios led to an increased SMA. However, the ratio 0.15 caused more than 20% SMA decrease. In addition to the SMA tests, the potential influence of biopolymers and extracellular substances, that are generated as a result of excess aerobic sludge hydrolysis, on membrane performance was determined by assessing the fouling potential of the liquid broth, taking into account parameters such as specific resistance to filtration (SRF) and supernatant filterability (SF). Addition of aerobic sludge to the anaerobic biomass resulted in a high membrane fouling potential. The increase in biopolymers could be ascribed to aerobic sludge hydrolysis. A clear positive correlation between the concentration of the colloidal fraction of biopolymer clusters (cBPC) and the SRF was observed and a negative correlation between the cBPC and the SF measured at the end of the above described SMA tests. The latter implies that sludge filtration resistance increases when more aerobic sludge is hydrolyzed, and thus more cBPC is released. During AnMBR operation, proteins significantly contributed to sludge filterability decrease expressed as SRF and SF, whereas the carbohydrate fraction of SMP was of less importance due to low concentrations. On the contrary, carbohydrates seemed to improve filterability and diminish SRF of the sludge. Albeit, cBPC increase caused an increase in mean TMP during the AnMBR operation, confirming that cBPC is positively correlated to membrane fouling.

  1. Modelling Cr(VI) removal by a combined carbon-activated sludge system

    Energy Technology Data Exchange (ETDEWEB)

    Orozco, A. Micaela Ferro [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata (Argentina); Contreras, Edgardo M. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata (Argentina)], E-mail:; Zaritzky, Noemi E. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata (Argentina); Fac. de Ingenieria, UNLP. 47 y 1 (B1900AJJ), La Plata (Argentina)


    The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2.

  2. Optimum operation conditions of nitrogen and phosphorus removal by a biofilm-activated-sludge system

    Institute of Scientific and Technical Information of China (English)


    In the biofilm and activated sludge combined system, denitrifying bacteria attached on the fibrous carriers in the anoxic tank, while the sludge containing nitrifying and phosphorus removal bacteria was only recirculated between the aerobic and anaerobic tanks. Therefore, the factors affected and restricted nitrification, denitrification and phosphorus removal in a traditional A/A/O process were resolved. This paper describes the optimum operation conditions for nitrogen and phosphorus removal using this system.

  3. Key factors governing alkaline pretreatment of waste activated sludge

    Institute of Scientific and Technical Information of China (English)

    Xianli Shi; Li Deng; Fangfang Sun; Jieyu Liang; Xu Deng


    Alkaline pretreatment is an effective technology to disintegrate sewage sludge, where alkali dosage and sludge concentration are two important factors. pH value or alkali concentration is usually adjusted in order to deter-mine a proper dosage of alkali. Our work has found that this is not a good strategy. A new parameter, the ratio of alkali to sludge (Ra/s), is more sensitive in controlling the alkali dosage. The sludge concentration Cs and reten-tion time t are two other important factors to consider. The validity of these arguments is confirmed with model-ing and experiments. The individual effect of Ra/s, Cs and t was studied separately. Then the combined effect of these three factors was evaluated. The sludge disintegration degree of 44.7%was achieved with the optimized factors. Furthermore, an alkaline-microwave combined pretreatment process was carried out under these optimized conditions. A high disintegration degree of 62.3%was achieved while the energy consumption of microwave was much lower than previously reported.

  4. Source Sludge Reduction by Conventional Activated Sludge Process Combined with Microwave Pretreatment%基于微波预处理的源头污泥减量研究

    Institute of Scientific and Technical Information of China (English)

    王亚炜; 肖庆聪; 阎鸿; 魏源送


    Excess sludge treatment and disposal are a great challenge to the operation and management of municipal wastewater treatment plants (WWTPs).Sludge source reduction based on the lysiscryptic growth principle by returning pretreated sludge into the aeration tank of conventional activated sludge (CAS) process is regarded as an effective method.Microwave pretreatment is a promising technology,yet there are no reports on its use in engineering-scale sludge reduction.A full scale test of sludge reduction was carried out in a CAS system coupled with microwave pretreatment for treating 300 m3/d of wastewater.The results showed that the sludge yield was reduced from 32.20-54.12 kg/d to 21.96 kg/d by combining microwave pretreatment.The sludge reduction rate was 29.1% to 40.9%.Significant amounts of carbon,nitrogen and phosphorus were released from the sludge pretreated by microwave,but it had little impact on the effluent quality of the CAS system.%剩余污泥的处理与处置已成为影响污水厂正常运行的重要挑战之一.基于溶胞—隐性生长原理,将经过预处理的污泥回流至好氧单元实现源头污泥减量被认为是一个有效的方法.微波预处理技术被认为是具有良好前景的技术之一,但目前尚未有工程规模的微波预处理—污泥回流减量的报道.基于微波预处理的源头污泥减量工程(污水设计处理规模为300 m3/d)运行结果表明,活性污泥系统引入微波预处理单元后,污泥产生量由32.20 ~ 54.12 kg/d减少至21.96kg/d,污泥减量率达29.1% ~40.9%.浓缩污泥经微波预处理后,污泥中碳、氮、磷的释放效果显著,但预处理的污泥回流后对活性污泥系统的出水水质没有影响.

  5. Application of a novel functional gene microarray to probe the functional ecology of ammonia oxidation in nitrifying activated sludge.

    Directory of Open Access Journals (Sweden)

    Michael D Short

    Full Text Available We report on the first study trialling a newly-developed, functional gene microarray (FGA for characterising bacterial and archaeal ammonia oxidisers in activated sludge. Mixed liquor (ML and media biofilm samples from a full-scale integrated fixed-film activated sludge (IFAS plant were analysed with the FGA to profile the diversity and relative abundance of ammonia-oxidising archaea and bacteria (AOA and AOB respectively. FGA analyses of AOA and AOB communities revealed ubiquitous distribution of AOA across all samples - an important finding for these newly-discovered and poorly characterised organisms. Results also revealed striking differences in the functional ecology of attached versus suspended communities within the IFAS reactor. Quantitative assessment of AOB and AOA functional gene abundance revealed a dominance of AOB in the ML and approximately equal distribution of AOA and AOB in the media-attached biofilm. Subsequent correlations of functional gene abundance data with key water quality parameters suggested an important functional role for media-attached AOB in particular for IFAS reactor nitrification performance and indicate possible functional redundancy in some IFAS ammonia oxidiser communities. Results from this investigation demonstrate the capacity of the FGA to resolve subtle ecological shifts in key microbial communities in nitrifying activated sludge and indicate its value as a tool for better understanding the linkages between the ecology and performance of these engineered systems.

  6. Anaerobic co-digestion of waste activated sludge and greasy sludge from flotation process: Batch versus CSTR experiments to investigate optimal design


    Girault, R.; Bridoux, G.; Nauleau, F.; Poullain, C.; Buffet, J.; Peu, P.; Sadowski, A.G.; Béline, F.


    In this study, the maximum ratio of greasy sluvdge to incorporate with waste activated sludge was investigated in batch and CSTR experiments. In batch experiments, inhibition occurred with a greasy sludge ratio of more than 20-30% of the feed COD. In CSTR experiments, the optimal greasy sludge ratio was 60% of the feed COD and inhibition occurred above a ratio of 80%. Hence, batch experiments can predict the CSTR yield when the degradation phenomenon are additive but cannot be used to determi...

  7. Design and simulation of an activated sludge unit associated to a continuous reactor to remove heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    D`Avila, J.S.; Nascimento, R.R. [Ambientec Consultoria Ltda., Aracaju, SE (Brazil)


    A software was developed to design and simulate an activated sludge unit associated to a new technology to remove heavy metals from wastewater. In this process, a continuous high efficiency biphasic reactor operates by using particles of activated peat in conjugation with the sludge unit. The results obtained may be useful to increase the efficiency or to reduce the design and operational costs involved in a activated sludge unit. (author). 5 refs., 2 tabs.

  8. Metagenomic and metatranscriptomic analysis of microbial community structure and gene expression of activated sludge.

    Directory of Open Access Journals (Sweden)

    Ke Yu

    Full Text Available The present study applied both metagenomic and metatranscriptomic approaches to characterize microbial structure and gene expression of an activated sludge community from a municipal wastewater treatment plant in Hong Kong. DNA and cDNA were sequenced by Illumina Hi-seq2000 at a depth of 2.4 Gbp. Taxonomic analysis by MG-RAST showed bacteria were dominant in both DNA and cDNA datasets. The taxonomic profile obtained by BLAST against SILVA SSUref database and annotation by MEGAN showed that activated sludge was dominated by Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Verrucomicrobia phyla in both DNA and cDNA datasets. Global gene expression annotation based on KEGG metabolism pathway displayed slight disagreement between the DNA and cDNA datasets. Further gene expression annotation focusing on nitrogen removal revealed that denitrification-related genes sequences dominated in both DNA and cDNA datasets, while nitrifying genes were also expressed in relative high levels. Specially, ammonia monooxygenase and hydroxylamine oxidase demonstrated the high cDNA/DNA ratios in the present study, indicating strong nitrification activity. Enzyme subunits gene sequences annotation discovered that subunits of ammonia monooxygenase (amoA, amoB, amoC and hydroxylamine oxygenase had higher expression levels compared with subunits of the other enzymes genes. Taxonomic profiles of selected enzymes (ammonia monooxygenase and hydroxylamine oxygenase showed that ammonia-oxidizing bacteria present mainly belonged to Nitrosomonas and Nitrosospira species and no ammonia-oxidizing Archaea sequences were detected in both DNA and cDNA datasets.

  9. [Research on the treatment of wastewater containing PVA by ozonation-activated sludge process]. (United States)

    Xing, Xiao-Qiong; Huang, Cheng-Lan; Liu, Min; Chen, Ying


    The wastewater containing polyvinyl alcohol (PVA) was characterized with poor biodegradability, and was difficult to remove. In order to find an economically reasonable and practical technology, the research on the removal efficiency of different concentration wastewater containing PVA by ozonation-activated sludge process was studied, and the result was compared with the traditional activated sludge process. The results showed that the ozonation-activated sludge process was not suitable for treating influent with COD below 500 mg x L(-1) and the wastewater PVA concentration was 10-30 mg x L(-1). When the influent COD was between 500-800 mg x L(-1) and the PVA concentration was 15-60 mg x L(-1), the system had advantages on dealing with this kind of wastewater, and the average removal efficiency of COD and PVA were 92.8% and 57.4%, which were better than the traditional activated sludge process 4.1% and 15.2% respectively. In addition, the effluent concentrations of COD could keep between 30-60 mg x L(-1). When the influent COD was 1 000-1 200 mg x L(-1) and the PVA concentration was 20-70 mg x L(-1), the average removal efficiencies of COD and PVA were 90.9% and 45.3%, which were better than the traditional activated sludge process 12.8% and 12.1% respectively, but the effluent should to be further treated. Compared with the traditional activated sludge process, ozonation-activated sludge process had high treatment efficiency, stable running effect, and effectively in dealing with industrial wastewater containing PVA.

  10. Extracellular polymeric substances and dewaterability of waste activated sludge during anaerobic digestion. (United States)

    Ye, Fenxia; Liu, Xinwen; Li, Ying


    Anaerobic digestion of waste activated sludge was conducted to gain insight into the mechanisms underlying change in sludge dewaterability during its anaerobic digestion. Unexpectedly, the results indicated that sludge dewatering properties measured by capillary suction time only deteriorated after 10 days of anaerobic digestion, after which dewaterability recovered and remained stable. The loosely bound extracellular polymeric substance (LB-EPS) content increased three-fold after 20 days of anaerobic digestion, and did not change significantly during the remaining 30 days. The tightly bound EPS (TB-EPS) content reduced slightly after 20 days of anaerobic digestion, and stabilized during the last 30 days. Polysaccharides (PS) and proteins (PN) content in LB-EPS increased after 10 days of anaerobic digestion. However, PS and PN contents in TB-EPS decreased slightly. The relationship analysis showed that only LB-EPS correlated with dewaterability of the sludge during anaerobic digestion.

  11. Vermicomposting of sludge from animal wastewater treatment plant mixed with cow dung or swine manure using Eisenia fetida. (United States)

    Xie, Dan; Wu, Weibing; Hao, Xiaoxia; Jiang, Dongmei; Li, Xuewei; Bai, Lin


    Vermicomposting of animal wastewater treatment plant sludge (S) mixed with cow dung (CD) or swine manure (SM) employing Eisenia fetida was tested. The numbers, weights, clitellum development, and cocoon production were monitored for 60 days at a detecting interval of 15 days. The results indicated that 100 % of the sludge can be the suitable food for growth and fecundity of E. fetida, while addition of CD or SM in sludge significantly (P < 0.05) increased the worm biomass and reproduction. The sludge amended with 40 % SM can be a great medium for the growth of E. fetida, and the sludge amended with 40 % CD can be a suitable medium for the fecundity of E. fetida. The addition of CD in sludge provided a better environment for the fecundity of earthworm than SM did. Moreover, vermicomposts obtained in the study had lower pH value, lower total organic carbon (TOC), lower NH4 (+)-N, lower C/N ratio, higher total available phosphorous (TAP) contents, optimal stability, and maturity. NH4 (+)-N, pH and TAP of the initial mixtures explained high earthworm growth. The results provided the theory basic both for management of animal wastes and the production of earthworm proteins using E. fetida.

  12. Roseomonas eburnea sp. nov., isolated from activated sludge. (United States)

    Wang, Chenghong; Deng, Shikai; Liu, Xin; Yao, Li; Shi, Chao; Jiang, Jin; Kwon, Soon-Wo; He, Jian; Li, Jiayou


    A Gram-stain-negative, aerobic, short rod-shaped, non-endospore-forming, ivory-pigmented and non-motile bacterium, designated strain BUT-5T, was isolated from activated sludge of an herbicides-manufacturing wastewater treatment facility in Jiangsu Province, China. The major fatty acids (>5 % of total fatty acids) were C16 : 0, C18 : 1 2-OH and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The predominant respiratory quinone was ubiquinone Q-10. The polar lipids profile of strain BUT-5T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unknown aminolipids. The DNA G+C content was 67.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BUT-5T showed the highest sequence similarities to Roseomonas soli 5N26T (97.5 % 16S rRNA gene sequence similarity), followed by Roseomonas lacus TH-G33T (97.3 %) and Roseomonas terrae DS-48T (97.1 %). Strain BUT-5T showed low DNA-DNA relatedness with Roseomonas soli KACC 16376T (41 %), Roseomonas lacus KACC 11678T (46 %) and Roseomonas terrae KACC 12677T (42 %), respectively. On the basis of phenotypic and genotypic properties, as well as chemotaxonomic data, strain BUT-5T represents a novel species of the genus Roseomonas, for which the name Roseomonas eburnea sp. nov. is proposed. The type strain is BUT-5T ( = CCTCC AB2013276T = KACC 17166T).

  13. Wastewater and sewage sludge application to willows and poplars grown in lysimeters-Plant response and treatment efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Dimitriou, I.; Aronsson, P. [Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Ecology building, P.O. Box 7043, SE 750 07 Uppsala (Sweden)


    Adding nutrient-rich residues such as municipal wastewater and sludge to willow and poplar short-rotation coppice gives more cost-effective and sustainable cultivation, but leaching to groundwater and disturbance to plant growth must be avoided. The effects of adding municipal wastewater irrigation to willows and poplars and sewage sludge to willows were compared in a two-year experiment. Wastewater irrigation enhanced plant growth. Near-zero nitrate-N concentrations occurred in drainage water when the root system of both species was well-established. The ability to retain N and P was satisfactory when poplars and willows were irrigated with wastewater. Thus relatively high additions of N and P with wastewater will probably not contaminate groundwater, but potential P leaching should not be underestimated. The same applies for sewage sludge applications to willow. (author)

  14. Radioactivity evaluation of Ebro river water and sludge treated in a potable water treatment plant located in the South of Catalonia (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Palomo, M.; Penalver, A.; Aguilar, C. [Unitat de Radioquimica Ambiental i Sanitaria, Universitat Rovira i Virgili, Consorci d' Aigues de Tarragona (CAT), Ctra. Nacional 340 Km. 1094, Ap. correus n.7, 43895 L' Ampolla Tarragona (Spain); Borrull, F. [Unitat de Radioquimica Ambiental i Sanitaria, Universitat Rovira i Virgili, Consorci d' Aigues de Tarragona (CAT), Ctra. Nacional 340 Km. 1094, Ap. correus n.7, 43895 L' Ampolla Tarragona (Spain)], E-mail:


    A potable water treatment plant with an average production rate of 4.3 m{sup 3}/s, providing several cities in the south of Catalonia (Spain) with drinking water, has been studied for a period of six years (2002-2007) regarding its capacity to remove several natural and anthropogenic radionuclides. First, gross alpha, gross beta and tritium activities were determined in ingoing and outgoing water samples. The values for all these parameters were below the Spanish normative limits established for waters for human consumption. For the sludge samples generated in the plant, we quantified some gamma emitting radioisotopes: natural ({sup 40}K, {sup 214}Pb, etc.) and artificial ({sup 60}Co, {sup 110m}Ag, etc.) which may be related to the geological or/and industrial activities (such as a nuclear power plant) located upstream of the PWTP on the Ebro River. Finally, when the sludge samples were compared with those from other water treatment plants, the influence of the industrial activities on the radioisotopes found in the analysed samples was confirmed since the activity levels for some of the isotopes quantified were 10 times higher.

  15. Emission of artificial sweeteners, select pharmaceuticals, and personal care products through sewage sludge from wastewater treatment plants in Korea. (United States)

    Subedi, Bikram; Lee, Sunggyu; Moon, Hyo-Bang; Kannan, Kurunthachalam


    Concern over the occurrence of artificial sweeteners (ASWs) as well as pharmaceuticals and personal care products (PPCPs) in the environment is growing, due to their high use and potential adverse effects on non-target organisms. The data for this study are drawn from a nationwide survey of ASWs in sewage sludge from 40 representative wastewater treatment plants (WWTPs) that receive domestic (WWTPD), industrial (WWTPI), or mixed (domestic plus industrial; WWTPM) wastewaters in Korea. Five ASWs (concentrations ranged from 7.08 to 5220 ng/g dry weight [dw]) and ten PPCPs (4.95-6930 ng/g dw) were determined in sludge. Aspartame (concentrations ranged from 28.4 to 5220 ng/g dw) was determined for the first time in sewage sludge. The median concentrations of ASWs and PPCPs in sludge from domestic WWTPs were 0.8-2.5 and 1.0-3.4 times, respectively, the concentrations found in WWTPs that receive combined domestic and industrial wastewaters. Among the five ASWs analyzed, the median environmental emission rates of aspartame through domestic WWTPs (both sludge and effluent discharges combined) were calculated to be 417 μg/capita/day, followed by sucralose (117 μg/capita/day), acesulfame (90 μg/capita/day), and saccharin (66μg/capita/day). The per-capita emission rates of select PPCPs, such as antimicrobials (triclocarban: 158 μg/capita/day) and analgesics (acetaminophen: 59 μg/capita/day), were an order of magnitude higher than those calculated for antimycotic (miconazole) and anthelmintic (thiabendazole) drugs analyzed in this study. Multiple linear regression analysis of measured concentrations of ASWs and PPCPs in sludge revealed that several WWTP parameters, such as treatment capacity, population-served, sludge production rate, and hydraulic retention time could influence the concentrations found in sludge.


    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing novel sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether these novel technolog...

  17. Modeling of organic substrate transformation in the high-rate activated sludge process. (United States)

    Nogaj, Thomas; Randall, Andrew; Jimenez, Jose; Takacs, Imre; Bott, Charles; Miller, Mark; Murthy, Sudhir; Wett, Bernhard


    This study describes the development of a modified activated sludge model No.1 framework to describe the organic substrate transformation in the high-rate activated sludge (HRAS) process. New process mechanisms for dual soluble substrate utilization, production of extracellular polymeric substances (EPS), absorption of soluble substrate (storage), and adsorption of colloidal substrate were included in the modified model. Data from two HRAS pilot plants were investigated to calibrate and to validate the proposed model for HRAS systems. A subdivision of readily biodegradable soluble substrate into a slow and fast fraction were included to allow accurate description of effluent soluble chemical oxygen demand (COD) in HRAS versus longer solids retention time (SRT) systems. The modified model incorporates production of EPS and storage polymers as part of the aerobic growth transformation process on the soluble substrate and transformation processes for flocculation of colloidal COD to particulate COD. The adsorbed organics are then converted through hydrolysis to the slowly biodegradable soluble fraction. Two soluble substrate models were evaluated during this study, i.e., the dual substrate and the diauxic models. Both models used two state variables for biodegradable soluble substrate (SBf and SBs) and a single biomass population. The A-stage pilot typically removed 63% of the soluble substrate (SB) at an SRT <0.13 d and 79% at SRT of 0.23 d. In comparison, the dual substrate model predicted 58% removal at the lower SRT and 78% at the higher SRT, with the diauxic model predicting 32% and 70% removals, respectively. Overall, the dual substrate model provided better results than the diauxic model and therefore it was adopted during this study. The dual substrate model successfully described the higher effluent soluble COD observed in the HRAS systems due to the partial removal of SBs, which is almost completely removed in higher SRT systems.

  18. The Assessment of Water Treatment Plant Sludge Properties and the Feasibility of Its Re-use according to Environmental Standards: Shahid Beheshti Water Treatment Plant Case Study, Hamadan

    Directory of Open Access Journals (Sweden)

    H. Pourmand


    Full Text Available Introduction & Objectives: Water treatment leads to produce large volumes of sludges in water treatment plants which are considered as solid waste, and should be managed appropriately and logically to avoid bioenvironmental effects. Materials & Methods: In this cross-sectional study, the required samples were taken from the sludge of Shahid Beheshti water treatment plant to assay physical and chemical characteristics during one year from summer, autumn and winter 93 until spring 94. Sampling and testing procedures were full fit according to standard methods. Results: The average concentration of total solids parameters (TSS, total suspended solids (TSS, and total dissolved solids (TDS were 22346, 21350 and 1005 mg/L, respectively. Among the heavy metals, aluminum, iron, manganese and zinc have the highest concentrations with the values of 1400, 956, 588 and 100 mg per kg of dry solids, respectively. The measured concentrations for cadmium were also higher than the permissible limits for agricultural purposes and discharges into the environment. The average concentrations of nickel were more than the recommended standard for industrial, agricultural and parkland application purposes. The concentrations were also slurry higher than the dry sludge. Conclusion: According to the past studies and results of this study, it could be concluded that contamination of heavy metals in sludge and slurry samples are more than dried sludge, .Therefore, if they are discharged into the environment, it is better to be disposed as dry sludges. Furthermore, because these types of waste sludges are routinely disposed in the environment, it is recommended to take the routine samples in order to measure the heavy metals and other relevant parameters contents of sludge before discharging it. (Sci J Hamadan Univ Med Sci 2016; 23 (1:57-64

  19. Study of kinetics of degradation of cyclohexane carboxylic acid by acclimated activated sludge. (United States)

    Wang, Chunhua; Shi, Shuian; Chen, Hongyan


    Activated sludge contains complex microorganisms, which are highly effective biodegrading agents. In this study, the kinetics of biodegradation of cyclohexane carboxylic acid (CHCA) by an acclimated aerobic activated sludge were investigated. The results showed that after 180 days of acclimation, the activated sludge could steadily degrade >90% of the CHCA in 120 h. The degradation of CHCA by the acclimated activated sludge could be modeled using a first-order kinetics equation. The equations for the degradation kinetics for different initial CHCA concentrations were also obtained. The kinetics constant, kd, decreased with an increase in the CHCA concentration, indicating that, at high concentrations, CHCA had an inhibiting effect on the microorganisms in the activated sludge. The effects of pH on the degradation kinetics of CHCA were also investigated. The results showed that a pH of 10 afforded the highest degradation rate, indicating that basic conditions significantly promoted the degradation of CHCA. Moreover, it was found that the degradation efficiency for CHCA increased with an increase in temperature and concentration of dissolved oxygen under the experimental conditions.

  20. A comparative adsorption study: 17β-estradiol onto aerobic granular sludge and activated sludge. (United States)

    Zheng, Xiao-ying; He, Yu-jie; Chen, Wei; Wang, Ming-yang; Cao, Su-lan; Ni, Ming; Chen, Yu


    Adsorption plays a significant role in removing hydrophobic 17β-estradiol (E2) from wastewater. Batch experiments were conducted to compare the adsorption of E2 onto activated aerobic granular sludge (AGS) and activated sludge (AS), and features evaluated included the adsorption kinetics, thermodynamics, and influence of other environmental factors. By using a non-chemical wet-heat technique, both AGS and AS were treated to inactivated status. Then, after loading E2, the adsorption equilibrium capacity of the AGS was found to be greater than that of the AS at the same initial concentration of E2. Moreover, both the adsorption processes corresponded to a pseudo-second-order kinetic model; the adsorption rate constant of AGS was found to be higher and the half-adsorption time was shorter than that of AS. Next, evaluations of adsorption isotherms and thermodynamics indicated that the adsorption process was mainly a physical process. Lower temperatures facilitated a higher equilibrium adsorption capacity. However, the adsorption binding sites of AGS were distributed more uniformly at higher temperature, in contrast to the distribution found for AS. Finally, acidic conditions and an appropriate ionic strength (0.4 mol/L) were found to be particularly conducive to the adsorption process. Overall, the results showed that AGS has the potential to adsorb E2 with significant efficiency, thereby offering a new and more efficient means of treating E2 and trace oestrogens in wastewater.

  1. Evaluation of activated sludge for biodegradation of propylene glycol as an aircraft deicing fluid. (United States)

    Delorit, Justin D; Racz, LeeAnn


    Aircraft deicing fluid used at airport facilities is often collected for treatment or disposal in order to prevent serious ecological threats to nearby surface waters. This study investigated lab scale degradation of propylene glycol, the active ingredient in a common aircraft deicing fluid, by way of a laboratory-scale sequencing batch reactor containing municipal waste water treatment facility activated sludge performing simultaneous organic carbon oxidation and nitrification. The ability of activated sludge to remove propylene glycol was evaluated by studying the biodegradation and sorption characteristics of propylene glycol in an activated sludge medium. The results indicate sorption may play a role in the fate of propylene glycol in AS, and the heterotrophic bacteria readily degrade this compound. Therefore, a field deployable bioreactor may be appropriate for use in flight line applications.

  2. Dehydrating sewage plant sludge using a mobile centrifuge; Deshidratacion de fangos en las depuradoras mediante una centrifuga movil

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Palou, P.; Arnau Planas de Farnes, A.; Arnau Figuerola, J.


    This study set out to examine various mechanical sludge dehydration systems as alternatives to the drying beds currently in existence in the sewage plants managed by the Costa Brava Consortium at Portbou, Colera, El Port de la Selva and Cadaques by determining their technical and economic feasibility. (Author) 11 refs.

  3. Pilot study of a fluidized-pellet-bed technique for simultaneous solid/liquid separation and sludge thickening in a sewage treatment plant

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.C.; Jin, P.K.; Yuan, H.L.; Wan, E.R.; Tambo, N.


    A fluidized-pellet-bed separator with movable sludge hoppers was applied in pilot scale for the separation and thickening of activated sludge mixture liquid. Under the condition of suspension SS around 4000 mg/L, polymer (CJX103, cationic, MW 5x10{sup 6}) dose at a dry solid ratio of 0.003 and upward flow rate at 5.4 m/hr, the fluidized pellet bed performed solid/liquid separation and sludge thickening well. The SS concentration of the treated water was about 5 mg/L on average and the moisture content of the sludge after screening for 5 mm was less than 94% which is much lower than that after conventional settling and thickening and easy to be finally disposed. At higher upward flow rate of 7.2 m/hr. similar result could also be obtained but higher polymer dose (solid ratio of 0.004) was required. The morphological characteristics and density-size relationship of the granular particles formed in the fluidized pellet bed were also investigated by image analysis and settling velocity measurement of individual particles. The two-dimensional fractal dimension was evaluated to be 1.6-1.8, showing a good quasi-spherical morphology of the granular particles with their density much higher than the conventional flocs. The results of the pilot study indicate a possible way to innovate the conventional secondary settling and gravitational thickening processes for solid/liquid separation and sludge handling, especially for small scale wastewater treatment plants to reach the goal of space saving and higher treatment efficiency. (author)

  4. Energy generation in a Microbial Fuel Cell using anaerobic sludge from a wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    Vinicius Fabiano Passos

    Full Text Available ABSTRACT In microbial fuel cells (MFCs, the oxidation of organic compounds catalyzed by microorganisms (anode generates electricity via electron transfer to an external circuit that acts as an electron acceptor (cathode. Microbial fuel cells differ in terms of the microorganisms employed and the nature of the oxidized organic compound. In this study, a consortium of anaerobic microorganisms helped to treat the secondary sludge obtained from a sewage treatment plant. The microorganisms were grown in a 250 mL bioreactor containing a carbon cloth. The reactor was fed with media containing acetate (as the carbon source for 48 days. Concomitantly, the electrochemical data were measured with the aid of a digital multimeter and data acquisition system. At the beginning of the MFC operation, power density was low, probably due to slow microorganism growth and adhesion. The power density increased from the 15th day of operation, reaching a value of 13.5 μW cm–2 after ca. 24 days of operation, and remained stable until the end of the process. Compared with data in the literature, this power density value is promising; improvements in the MFC design and operation could increase this value even further. The system investigated herein employed excess sludge as a biocatalyst in an MFC. This opens up the possibility of using organic acids and/or carbohydrate-rich effluents to feed MFCs, and thereby provide simultaneous effluent treatment and energy generation.


    Directory of Open Access Journals (Sweden)



    Full Text Available The purpose of this study was to determine the content of metals elements in the sludge of Ibn Ziad sewage treatment plant of Constantine in order to preserve its quality for subsequent use in agriculture. The use of X-ray fluorescence spectroscopy allowed us to identify the following constituents in this mud: Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn Fe, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Ba, Pb. These elements represent 49.82 % of the total mass of the sludge. The elements present with regulated content limit are chromium, copper, nickel, lead and zinc. They occur respectively with the following concentrations: 0.27 mg·g-1, 0.48 mg·g-1, 0.11 mg·g-1, 0.35 mg·g-1 and 2.70 mg·g-1. We have achieved an extraction for evaluating the concentration of the dissolved nitrate ions, the chemical oxygen demand (COD, and pH. The nitrate ions were transformed into sodium paranitrosalicylate to be dosed by ultraviolet-visible (UV-Vis spectroscopy at 420 nm. The concentration measured was 0.12 mg·g-1. The measuring of the COD issued a value of 0.45 mg·g-1. pH was 7.1.

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

    Directory of Open Access Journals (Sweden)

    Chamorro-Trenado, M. A.


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

  7. The content of chromium and copper in plants and soil fertilized with sewage sludge with addition of various amounts of CaO and lignite ash

    Directory of Open Access Journals (Sweden)

    Wysokiński Andrzej


    Full Text Available The influence of fertilization with fresh sewage sludge with the addition of calcium oxide and lignite ash in the proportions dry mass 6:1, 4:1, 3:1 and 2:1 on the content of chromium and copper in plants and soil and uptake of these elements was investigated in pot experiment. Sewage sludge were taken from Siedlce (sludge after methane fermentation and Łuków (sludge stabilized in oxygenic conditions, eastern Poland. The chromium content in the biomass of the test plants (maize, sunflower and oat was higher following the application of mixtures of sewage sludge with ash than of the mixtures with CaO. The copper content in plants most often did not significantly depend on the type of additives to the sludge. Various amounts of additives to the sewage sludge did not have a significant effect on the contents of either of the studied trace elements in plants. The contents of chromium and copper in soil after 3 years of cultivation of plants were higher than before the experiment, but these amounts were not significantly differentiated depending on the type and the amount of the used additive (i.e. CaO vs. ash to sewage sludge.

  8. The response of maize (Zea mays L.) plant assisted with bacterial consortium and fertilizer under oily sludge. (United States)

    Shahzad, Asim; Saddiqui, Samina; Bano, Asghari


    The objective of this study was to evaluate the role of PGPR consortium and fertilizer alone and in combination on the physiology of maize grown under oily sludge stress environment as well on the soil nutrient status. Consortium was prepared from Bacillus cereus (Acc KR232400), Bacillus altitudinis (Acc KF859970), Comamonas (Delftia) belonging to family Comamonadacea (Acc KF859971) and Stenotrophomonasmaltophilia (Acc KF859973). The experiment was conducted in pots with complete randomized design with four replicates and kept in field. Oily sludge was mixed in ml and Ammonium nitrate and Diammonium phosphate (DAP) were added at 70 ug/g and 7 ug/g at sowing. The plant was harvested at 21 d for estimation of protein, proline and antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). To study the degradation, total petroleum hydrocarbon was extracted by soxhelt extraction and extract was analyzed by GC-FID at different period after incubation. Combined application of consortium and fertilizer enhanced the germination %, protein and, proline content by 90,130 and 99% higher than untreated maize plants. Bioavailability of macro and micro nutrient was also enhanced with consortium and fertilizer in oily sludge. The consortium and fertilizer in combined treatment decreased the superoxide dismutase (SOD), peroxidase dismutase (POD) of the maize leaves grown in oily sludge. Degradation of total petroleum hydrocarbon (TPHs) was 59% higher in combined application of consortium and fertilizer than untreated maize at 3 d. The bacterial consortium can enhanced the maize tolerance to oily sludge and enhanced degradation of total petroleum hydrocarbon (TPHs). The maize can be considered as tolerant plant species to remediate oily sludge contaminated soils.

  9. Enhancing the use of waste activated sludge as bio-fuel through selectively reducing its heavy metal content. (United States)

    Dewil, Raf; Baeyens, Jan; Appels, Lise


    Power plant or cement kiln co-incineration are important disposal routes for the large amounts of waste activated sludge (WAS) which are generated annually. The presence of significant amounts of heavy metals in the sludge however poses serious problems since they are partly emitted with the flue gases (and collected in the flue gas dedusting) and partly incorporated in the ashes of the incinerator: in both cases, the disposal or reuse of the fly ash and bottom ashes can be jeopardized since subsequent leaching in landfill disposal can occur, or their "pozzolanic" incorporation in cement cannot be applied. The present paper studies some physicochemical methods for reducing the heavy metal content of WAS. The used techniques include acid and alkaline thermal hydrolysis and Fenton's peroxidation. By degrading the extracellular polymeric substances, binding sites for a large amount of heavy metals, the latter are released into the sludge water. The behaviour of several heavy metals (Cd, Cr, Cu, Hg, Pb, Ni, Zn) was assessed in laboratory tests. Results of these show a significant reduction of most heavy metals.

  10. Enhanced Biological Phosphorus Removal with Pseudomonas putida GM6 from Activated Sludge

    Institute of Scientific and Technical Information of China (English)


    The enhanced biological phosphorus removal (EBPR) method is widely adopted for phosphorus removal from wastewater, yet little is known about its microbiological and molecular mechanisms. Therefore, it is difficult to predict and control the deterioration of the EBPR process in a large-scale municipal sewage treatment plant. This study used a novel strain isolated in the laboratory, Pseudomonas putida GM6, which had a high phosphate accumulating ability and could recover rapidly from the deteriorated system and enhance the capability of phosphorus removal in activated sludge. Strain GM6 marked with gfp gene, which was called GMTR, was delivered into a bench-scale sequencing batch reactor (SBR)of low efficiency, to investigate the colonization of GMTR and removal of phosphorus. After 21 days, the proportion of GMTR in the total bacteria of the sludge reached 9.2%, whereas the phosphorus removal rate was 96%, with an effluent concentration of about 0.2 mg L-1. In the reactor with the addition of GMTR, phosphorus was removed quickly, in 1 h under anaerobic conditions, and in 2 h under aerobic conditions. These evidences were characteristic of EBPR processes.Field testing was conducted at a hospital sewage treatment facility with low phosphorus removal capability. Twentyone days after Pseudononas putida GM6 was added, effluent phosphorus concentration remained around 0.3 mg L-1,corresponding to a removal rate of 96.8%. It was therefore demonstrated that Pseudomonas putida GM6 could be used for a quick startup and enhancement of wastewater biological phosphorus removal, which provided a scientific basis for potential large-scale engineering application.

  11. Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community (United States)

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


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

  12. Hard Sludge Formation in Modern Steam Generators of Nuclear Power Plants Formation, Risks and Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Strohmer, F.


    This article will discuss the physical and chemical reasons for the increased tendency to form hard sludge on the secondary side of modern nuclear steam generators (SG). The mechanism of hard sludge induced denting will be explained. Moreover, advice on operation and maintenance to mitigate hard sludge formation and denting damages will be presented.

  13. Effect of magnetic nanoparticles on the performance of activated sludge treatment system. (United States)

    Ni, Shou-Qing; Ni, Jianyuan; Yang, Ning; Wang, Juan


    Both short-term and long-term exposure experiments were carried out to investigate the influence of magnetic nanoparticles (NPs) on activated sludge. The short-term presence of 50-200 mg/L of NPs decreased total nitrogen (TN) removal efficiencies, resulted from the acute toxicity of a shock load of NPs. However, long-term exposure of 50 mg/L magnetic NPs were observed to significantly improve TN removal efficiency, partially due to the self-repair function of activated sludge and magnetic-induced bio-effect. Sludge properties and extracellular polymer substrates secretion were affected. Additional investigations with enzyme and FISH assays indicated that short-term exposure of 50 mg/L magnetic NPs led to the abatement of nitrifying bacteria. However, the activities of the enzyme nitrite oxidoreductase and key denitrifying enzymes were increased after long-term exposure.

  14. IASON - Intelligent Activated Sludge Operated by Nanotechnology - Hydrogel Microcarriers in Wastewater Treatment (United States)

    Fleit, E.; Melicz, Z.; Sándor, D.; Zrínyi, M.; Filipcsei, G.; László, K.; Dékány, I.; Király, Z.

    Performance of biological wastewater treatment depends to a large extent on mechanical strength, size distribution, permeability and other textural properties of the activated sludge flocs. A novel approach was developed in applying synthetic polymer materials to organize floc architecture instead of spontaneously formed activated sludge floc. Developed microcarrier polymer materials were used in our experiments to mitigate technological goals. Preliminary results suggest that the PVA-PAA (polyvinyl alcohol-polyacrylic acid copolymer) is a feasible choice for skeleton material replacing "traditional" activated sludge floc. Use of PVA-PAA hydrogel material as microreactors and methods for biofilm formation of wastewater bacteria on the carrier material are described. Laboratory scale experimental results with microscopic size bioreactors and their potential application for simultaneous nitrification and denitrification are presented.

  15. How adaptation and mass transfer control the biodegradation of linear alkylbenzene sulfonate by activated sludge. (United States)

    Rittmann, B E; Tularak, P; Lee, K C; Federle, T W; Itrich, N R; Kaiser, S K; Shi, J; McAvoy, D C


    We use a nonsteady-state model to evaluate the effects of community adaptation and sorption kinetics on the fate of linear alkylbenzene sulfonate (LAS) in batch experiments conducted with activated sludge that was continuously fed different concentrations of LAS. We observed a sharp decrease in the biodegradation rate between 30 and 60 minutes and the presence of an LAS residual at the end of the batch experiments. The modeling analysis indicates that these phenomena were caused by relatively slow inter-phase mass transport of LAS. The modeling analyses also showed that the amount of LAS-degrading biomass increased when the continuous activated sludge was fed a higher LAS concentration. Although community adaptation to LAS involved accumulation of more LAS degraders, the increase was not proportional to the feed concentration of LAS, which supports the concept that LAS degraders also utilized portions of the general biochemical oxygen demand (BOD) fed to the continuous activated sludge systems.

  16. Effect of activated sludge properties and membrane operation conditions on fouling characteristics in membrane bioreactors. (United States)

    Choi, Hyeok; Zhang, Kai; Dionysiou, Dionysios D; Oerther, Daniel B; Sorial, George A


    Biofouling control is considered to be a major challenge in operating membrane bioreactors (MBRs) for the treatment of wastewater. This study examined the impact of biological, chemical, and physical properties of activated sludge on membrane filtration performance in laboratory-scale MBRs. Sludges with different microbial communities were produced using pseudo-continuous stirred-tank reactors and pseudo-plug flow reactors treating a synthetic paper mill wastewater. Various filtration resistances were used to investigate membrane fouling characteristics, and molecular biology tools targeting 16S ribosomal DNA gene sequences were used to identify predominant bacterial populations in the sludges or attached to the fouled membranes. Filtration experiments using axenic cultures of Escherichia coli, Acinetobacter calcoaceticus, and Gordonia amarae were also performed to better understand the initiation and development of biofouling. The results showed that the tendency of membranes to biofoul depended upon membrane operating conditions as well as the properties of the activated sludge in the MBR systems. Specific bacterial populations, which were not dominant in the activated sludges, were selectively accumulated on the membrane surface leading to the development of irreversible biofouling.


    Directory of Open Access Journals (Sweden)

    Małgorzata Cimochowicz-Rybicka


    Full Text Available Production of a methane-rich gas (‘biogas’ is contemporary popular sludges processing technology which allows to generate thermal and/or electric energy. Formal requirements issued by the European Union to promote so called renewable energy resources made these process more attractive leading to its application in WWTPs which were designed based on different sludge handling processes. Authors (as active design engineers noted that dimensioning sludge digestion chamber is usually based on SRT assessment without any emphasis on sludge characteristics. Bio-mass characteristics and the estimation of its activity with respect to methane production are of great importance, from both scientific and practical points of view, as anaerobic digestion appears to be one of crucial processes in municipal wastewater handling and disposal. The authors propose respirometric tests to estimate a biomass potential to produce ‘a biogas’ and several years’ laboratory and full scale experience proved its usefulness and reliability both as a measurement and a design tool applicable in sludge handling. Dimensioning method proposed by authors, allows to construct and optimize operation of digestion chambers based on a methanogenic activity.

  18. Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids. (United States)

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


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

  19. Laboratory bioassay for assessing the effects of sludge supernatant on plant growth and vesicular-arbuscular mycorrhiza formation

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, K.S.; Liberta, A.E.


    A laboratory bioassay is described for assessing the effects of sludge supernatant on juvenile corn growth and the ability of vesicular-arbuscular (VA) mycorrhizal fungi, indigenous to coal spoil, to form mycorrhizae. The bioassay demonstrated that application rates can be identified that have the potential to promote increased plant dry weight without suppressing the formation of VA mycorrhizae in a plant's root system.


    Directory of Open Access Journals (Sweden)

    N. Mehrdadi , A. A. Azimi , G. R. Nabi Bidhendi, B. Hooshyari


    Full Text Available Advanced compact wastewater treatment processes are being looked for by cities all over the world as effluent standards are becoming more stringent and land available for treatment plants more scarce. In this investigation, a new biofilm process for this purpose was studied. The design and operational criteria of a full scale extended aeration activated sludge system was compared with an H-IFAS reactor which has been operated at a pilot scale. The objective was to define the feasibility of using the H-IFAS (Hybrid Integrated Fixed Film Activated Sludge reactor for upgrading the existing wastewater treatment plants with conventional processes. The results showed that besides the considerable difference between the organic loading of the two processes, H-IFAS reactor has a very good capability to reduce simultaneously the concentration of nitrogen and phosphorus. Organic degradation rate in extended aeration and H-IFAS systems were 0.3 and 6.22 kgCOD/ at 23.48°C, respectively. Nitrification, denitrification and phosphorus removal rate for the H-IFAS reactor were 343.28 g N/, 338.17 gN/, and 204.78gPO4-P/, respectively. At the same conditions, these criteria for extended aeration activated sludge processes were obtained as 75gN/, 28.5 gN/ and 7 gPO4-P/, respectively.

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

    Directory of Open Access Journals (Sweden)

    Lacatusu Radu


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

  2. Impact of accelerated electrons on activating process and foaming potential of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Cuba, V.; Pospisil, M. E-mail:; Mucka, V.; Jenicek, P.; Silber, R.; Dohanyos, M.; Zabranska, J


    The process of activation is an important part of wastewater treatment technology. It can be affected in many ways, not least by using radiation. The paper describes effects of pre-irradiation of small part of biomass on activated sludge process. It has been shown, that relatively low dose of accelerated electrons can positively affect many parameters of the system.

  3. Theoretical evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process

    Institute of Scientific and Technical Information of China (English)

    ZHU Gui-bing; PENG Yong-zhen


    Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduced based on the mass balance of nitrate in the last stage. The comparison of pre-denitrification process and step feed process in the aspects of nitrogen removal efficiency, volume of reactor and building investment was studied, and the results indicated that step-feed anoxic/oxic activated sludge process was superior to pre-denitrification process in these aspects.

  4. Optimization of the do concentration in activated sludge systems treating petrochemical effluents

    Energy Technology Data Exchange (ETDEWEB)

    Van Haandel, A.; Cavalcanti, P. F.F.; Medeiros, U. T. P.


    Electric energy is normally one the important cost factors of activated sludge systems. If the aeration intensity is reduced, energy consumption will be lower, but the resulting reduction of the dissolved oxygen concentration in the mixed liquor may affect the treatment system in three ways: (1) reduction of the efficiency of organic material removal and nitrification, resulting in higher residual BOD, COD and NH{sub 3} concentrations in the effluent, (2) reduction of the metabolic activity of heterotrophic or auto trophic bacteria and (3) deterioration of the sludge settleability which may reduce the separation efficiency in the final settler. (Author)

  5. Control of the aeration volume in an activated sludge process for nitrogen removal. (United States)

    Samuelsson, P; Carlsson, B


    Biological nitrogen removal in an activated sludge process is obtained by two biological processes; nitrification and denitrification. Nitrifying bacteria need dissolved oxygen and a sufficiently large aeration volume for converting ammonium to nitrate in the wastewater. The objective of this paper is to develop an automatic control strategy for adjusting the aerated volume so that the effluent ammonium level can be kept close to a desired value despite major changes in the influent load. The strategy is based on applying exact linearization of the IAWO Activated Sludge Process Model No 1. Simulation results show that the suggested controller effectively attenuates process disturbances.

  6. Activation of Rejected Fly Ash Using Flue Gas Desulphurization (FGD) Sludge

    Institute of Scientific and Technical Information of China (English)

    QIAO Xiu-chen; POON Chisun; LIN Zong-shou


    Low-grade fly ash ( rejected fly ash, rFA ), a significant portion of the pulverized fuel ash ( PFA ) produced from coal-fired power plauts and rejected from the ash classifying process, remains unused due to its high carbon content and large particle size ( > 45μm ). But it is thonght that the rejected ash may have potential uses in chemical stabilization/solidification ( S/S ) processes which need relatively lower strengths and a lower chemical reactivity. Flue Gas Desulphurisation ( FGD ) sludge is a by-product of air pollution control equipment in coal fired power plants whose chemical composition is mainly gypsum. As there is no effective usage of both of these two ntaterials , it is of interest to research on the possible octtivation of rFA using FGD . This paper presents experimental results of a study on the properties of rFA activated by the FGD in rFA-cement pastes. Different percetages of FGD were added into the mix to study the effects of the FGD on the reaction of the rFA blended cement pastes.The results show that FGD takes effect as an activator only at late curing ages. Adding Ca ( OH)2 enhances the effect of FGD on activating the hytration of rFA. Also, 10% FGD by weight of rFA is the optimal addition in the rFA-cement pastes. The results of the compressive strength measurements correlate well with the porosity results.

  7. Levels, composition profiles and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sludge from ten textile dyeing plants. (United States)

    Ning, Xun-An; Lin, Mei-Qing; Shen, Ling-Zhi; Zhang, Jian-Hao; Wang, Jing-Yu; Wang, Yu-Jie; Yang, Zuo-Yi; Liu, Jing-Yong


    As components of synthetic dyes, polycyclic aromatic hydrocarbons (PAHs) are present as contaminants in textile dyeing sludge due to the recalcitrance in wastewater treatment process, which may pose a threat to environment in the process of sludge disposal. In order to evaluate PAHs in textile dyeing sludge, comprehensive investigation comprising 10 textile dyeing plants was undertaken. Levels, composition profiles and risk assessment of 16 EPA-priority PAHs were analyzed in this study. The total concentrations of 16 PAHs (∑16 PAHs) varied from 1463 ± 177 ng g(-1) to 16,714 ± 1,507 ng g(-1) with a mean value of 6386 ng g(-1). The composition profiles of PAHs were characterized by 3- and 4-ring PAHs, among which phenanthrene, anthracene and fluoranthene were the most dominant components. The mean benzo[a]pyrene equivalent (BaPeq) concentration of ∑16 PAHs in textile dyeing sludge was 423 ng g(-1), which was 2-3 times higher than concentrations reported for urban soil. According to ecological risk assessment, the levels of PAHs in the textile dyeing sludge may cause a significant risk to soil ecosystem after landfill or dumping on soil.

  8. Zero-valent iron enhanced methanogenic activity in anaerobic digestion of waste activated sludge after heat and alkali pretreatment. (United States)

    Zhang, Yaobin; Feng, Yinghong; Quan, Xie


    Heat or alkali pretreatment is the effective method to improve hydrolysis of waste sludge and then enhance anaerobic sludge digestion. However the pretreatment may inactivate the methanogens in the sludge. In the present work, zero-valent iron (ZVI) was used to enhance the methanogenic activity in anaerobic sludge digester under two methanogens-suppressing conditions, i.e. heat-pretreatment and alkali condition respectively. With the addition of ZVI, the lag time of methane production was shortened, and the methane yield increased by 91.5% compared to the control group. The consumption of VFA was accelerated by ZVI, especially for acetate, indicating that the acetoclastic methanogenesis was enhanced. In the alkali-condition experiment, the hydrogen produced decreased from 27.6 to 18.8 mL when increasing the ZVI dosage from 0 to 10 g/L. Correspondingly, the methane yield increased from 1.9 to 32.2 mL, which meant that the H2-utilizing methanogenes was enriched. These results suggested that the addition of ZVI into anaerobic digestion of sludge after pretreated by the heat or alkali process could efficiently recover the methanogenic activity and increase the methane production and sludge reduction.

  9. Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition. (United States)

    Zhang, Ying; Zhang, Chaojie; Zhang, Xuan; Feng, Leiyu; Li, Yongmei; Zhou, Qi


    Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA (volatile fatty acid) in a shorter time can be achieved at pH10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supernatant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.

  10. Biodegradation of toluene diamine (TDA) in activated sludge acclimated with aniline and TDA. (United States)

    Asakura, S; Okazaki, S


    The biodegradability of toluene diamine (TDA) which has been regarded as a "recalcitrant compound" was examined in activated sludges. In this study, a microorganic-enzyme system which metabolized TDA was obtained by acclimating the activated sludge with aniline and TDA. In the sludge subject to be 200 days' acclimation, the considerable increase in respiration rate with the addition of TDA, accompanied the sharp decrease in its concentration. This indicated that TDA was metabolized fortuitously. The rate of biodegradation of TDA in the absence of aniline was first order with respect to its concentration when the initial TDA concentration was less than about 5 mg/l. The rate constant in this relation was proportional to mixed liquor suspended solid (MLSS). However, when the initial TDA concentration exceeded 5 mg/l, the plots were deviated from a first order rate equation.

  11. Sludge concentration dynamic distribution and its impact on the performance of UNITANK

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fa-gen; LIU Jun-xin; SUI Jun


    UNITANK is a biological wastewater treatment process that combines the advantages of traditional activated sludge process and sequencing batch reactor, which is divided into Tank A, B and C. In this study, the sludge distribution and its impact on performance of UNITANK were carried out in Liede Wastewater Plant (WWTP) of Guangzhou, China. Results showed that there was a strong affiliation between Tank A and B of the system in sludge concentration distribution. The initial sludge concentration in Tank A could present the sludge distribution of the whole system. The sludge distribution was mainly influenced by hydraulic condition. Unsteady sludge distribution had an impact on variations of substrates in reactors, especially in decisive reactor, and this could lead to failure of system. Settler could partially remove substrates such as COD and NO3-N, but there was adventure of sludge deterioration. The rational initial sludge concentration in Tank A should be 4000-6000 mg/L MLSS.

  12. Enhancement of the performance of activated carbons as municipal odor removal media by addition of a sewage-sludge-derived phase. (United States)

    Sioukri, Evilambia; Bandosz, Teresa J


    Two commercial low-cost activated carbons and wood-based char were mixed with dewatered sludge and pyrolized at 950 degrees C. The sludge content on a dry basis was 23%. The obtained composite adsorbents were characterized from the point of view of surface chemistry (pH) and texture (adsorption of nitrogen at its boiling point: surface area, pore volume, pore size distributions). Then hydrogen sulfide breakthrough capacities were measured using the home-designed dynamic test. The results revealed a significant increase in the capacity of the composite adsorbents compared to the unmodified carbons. Moreover, that increase was a few times greater than the hypothetical one predicted when desulfurization performance would be the sum of the contributions of both the sludge-derived and carbon phases. This is attributed to a synergetic effect related to the dispersion of the catalysts and the presence of small pores. Mixing activated carbon provides the active centers for oxidation (coming from sludge) and the developed pore system (from the activated carbon) where products of oxidation can be stored. Moreover, in the hydrophobic pore space the volatile organic compounds present in effluent air from a municipal waste treatment plant can be adsorbed. The selectivity for H2S oxidation, as in the case of pure activated carbon, depends on the pore sizes. Smaller pores lead to a higher yield of sulfuric acid; larger pores lead to a higher yield of sulfur.

  13. Presence of helminth eggs in sewage sludge from waste water plants; Presencia de huevos de helmintos en lodos procedentes de la depuracion de aguas

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Muro, J. L.; Garcia Orenes, F.; Nieto Asensio, N.; Bonora, I. B.; Morenilla Martinez, J. J.


    Land application of sewage sludge is a usual practice in wide areas of the Comunidad Valencia, due the low organic contents and nutrients of the soils, and the sewage sludge is a suitable material to use os organic amendment of soils. However the use of sewage sludge involves a very detailed characterization of sewage, to avoid sanitary hazards as the presence of helminth eggs and its high resistant to most of the treatment used to stabilize sewage sludge. The aim of this work was determine the parasitic contamination of helminths found in sewage sludge, stabilized by anaerobic digestion, from two waste water plants of Alicante (Alcoy y Benidorm) destined to agricultural land. Also it was studies the evolution of helminth eggs content of a sewage sludge subjected to composting process. (Author) 12 refs.

  14. Biological hydrolysis and acidification of sludge under anaerobic conditions: The effect of sludge type and origin on the production and composition of olatile fatty acids

    DEFF Research Database (Denmark)

    Ucisik, Ahmed Süheyl; Henze, Mogens


    that fermentation of primary sludge produced the highest amount of volatile fatty acids (VFAs) and generated significantly higher COD- and VFA-yields compared to the other sludge types regardless of which WWTP the sludge originated from. Fermentation of activated and primary sludge resulted in 1.9–5.6% and 8....... In this study, the feasibility of implementing biological hydrolysis and acidification process on different types of municipal sludge was investigated by batch and semi-continuous experiments. The municipal sludge originated from six major treatment plants located in Denmark were used. The results showed...... of fermentation for full-scale application was roughly estimated based on the experiments performed in semi-continuous reactors. The results revealed that even though the VFA production of primary sludge was higher compared to activated sludge, substantial amounts of VFA could be produced by fermentation...

  15. Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design

    Directory of Open Access Journals (Sweden)

    B. Subha


    Full Text Available 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 (R2 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.

  16. Nonlinear modeling of activated sludge process using the Hammerstein-Wiener structure

    Directory of Open Access Journals (Sweden)

    Frącz Paweł


    Full Text Available The paper regards to physical model of the Activated Sludge Process, which is a part of the wastewater treatment. The aim of the study was to describe nitrogen transformation process and the demand of chemical fractions, involved in the ASP process. Moreover, the non-linear relationship between the flow of wastewater and the consumed electrical energy, used by the blowers, was determined. Such analyses are important from the economical and environmental point of view. Assuming that the total power does not change the blower is charging during a year an energy amount of approx. 613 MW. This illustrates in particular the scale of the demand for energy consumption in the biological aeration unit. The aim is to minimize the energy consumption through first building a model of ASP and then through optimization of the overall process by modifying chosen parameter in numerical simulations. In this paper example measurement and analysis results of nitrite and ammonium nitrogen concentrations in the aeration reactor and the active power consumed by blowers for the aeration process were presented. Further the ASP modeling procedure, which uses the Hammerstein-Wiener structure and example verification results were presented. Based on the achieved results it was stated that the developed set of methodologies may be used to improve and expand the overriding control system for system for wastewater treatment plant.


    Directory of Open Access Journals (Sweden)

    Magdalena Filkiewicz


    Full Text Available According to the National Waste Management Plan 2014 (NWMP 2014 recommended method of utilization of sewage sludge is using it for agricultural purposes or for land reclamation. The sludge is characterized by a high content of organic substances, microelements and biogenic compounds, through which sewage sludge possess high soil formation and fertilization properties. It is assumed that in 2020 approximately 30% of the sludge production will be used for agricultural purposes, while 15% will be used for land reclamation. We have to remember that prior to the introduction of sludge into the ground, security, health and chemical requirements should be met. In order to use the sludge for agricultural purposes, the process of their disposal should be previously carried out e.g. Autoheated Thermophilic Aerobic Digestion (ATAD. It allows for hygienisation of sewage sludge and reducing the heavy metal content. As a result, processed sewage sludge is characterized by the presence of heavy metals in amounts which do not exceed the standards. It is also deprived of microorganisms. The stabilized sludge is characterized by high phosphorus and calcium content. Therefore there is possibility to use the examined sludge in agriculture.

  18. Degradation of PPCPs in activated sludge from different WWTPs in Denmark

    DEFF Research Database (Denmark)

    Chen, Xijuan; Vollertsen, Jes; Nielsen, Jeppe Lund


    was performed to assess the removal of frequently occurring pharmaceuticals (Naproxen, Fenoprofen, Ketoprofen, Dichlofenac, Carbamazepine) and the biocide Triclosan in activated sludge from four different Danish WWTPs. The respective degradation constants were compared to operational parameters previous shown...... to be of importance for degradation of micropollutants such as biomass concentration, and sludge retention time (SRT). The most rapid degradation, was observed for NSAID pharmaceuticals (55–90 % for Fenoprofen, 77–94 % for Ketoprofen and 46–90 % for Naproxen), followed by Triclosan (61–91 %), while Dichlofenac...


    Directory of Open Access Journals (Sweden)



    Full Text Available Textile industry wastewaters contain high concentrations of organic matter, toxic substances and dyes and pigments, and are harmful to receiving environment. Activated sludge system at pilot scale with continuous feeding, was used for the treatment of a dyeing unit effluent. The results showed that treatment allows a removal rate of 40-56 % of chemical oxygen demand (COD, and 13 to 30 % of color. The adsorption on sludge appears to be the main process responsible for the color removal of wastewater generated by textile industry.

  20. Modeling integrated fixed-film activated sludge and moving-bed biofilm reactor systems II: evaluation. (United States)

    Boltz, Joshua P; Johnson, Bruce R; Daigger, Glen T; Sandino, Julian; Elenter, Deborah


    A steady-state model presented by Boltz, Johnson, Daigger, and Sandino (2009) describing integrated fixed-film activated sludge (IFAS) and moving-bed biofilm reactor (MBBR) systems has been demonstrated to simulate, with reasonable accuracy, four wastewater treatment configurations with published operational data. Conditions simulated include combined carbon oxidation and nitrification (both IFAS and MBBR), tertiary nitrification MBBR, and post denitrification IFAS with methanol addition as the external carbon source. Simulation results illustrate that the IFAS/MBBR model is sufficiently accurate for describing ammonia-nitrogen reduction, nitrate/nitrite-nitrogen reduction and production, biofilm and suspended biomass distribution, and sludge production.

  1. Identification of Triclosan-O-Sulfate and other transformation products of Triclosan formed by activated sludge. (United States)

    Chen, Xijuan; Casas, Mònica Escolà; Nielsen, Jeppe Lund; Wimmer, Reinhard; Bester, Kai


    Aerobic degradation experiments of Triclosan were performed in activated sludge to identify possible transformation products for this compound. During 7 days, the formation of biotransformation products such as 2,4-Dichlorophenol, 4-Chlorocatechol, 5-Hydroxy-Triclosan and other Monohydroxy-Triclosan derivatives as well as Dihydroxy-Triclosan-derivatives were observed. The structure of 5-Hydroxy-Triclosan was elucidated by NMR data for the first time in sludge degradation experiments. Additionally the production of a hitherto unknown transformation product in sludge, i.e., Triclosan-O-Sulfate was detected. During the incubations, the concentrations of this transformation product changed from zero to 330 μg L(-1). Based on the analysis of the biodegradation products, three types of reactions were identified: 1) chemical scission of ether bond to form phenols and catechols, 2) addition of OH moieties to the aromatic ring, and 3) adding of methyl or sulfate groups to the original hydroxyl group.

  2. Gas chromatographic analysis of polyhydroxybutyrate in activated sludge: a round-robin test. (United States)

    Baetens, D; Aurola, A M; Foglia, A; Dionisi, D; van Loosdrecht, M C M


    Polyhydroxyalkanoates (PHA) and poly-beta-hydroxybutyrate (PHB) in particular have become compounds which is routinely investigated in wastewater research. The PHB analysis method has only recently been applied to activated sludge samples where PHA contents might be relatively low. This urges the need to investigate the reproducibility of the gas chromatographic method for PHB analysis. This was evaluated in a round-robin test in 5 European laboratories with samples from lab-scale and full-scale enhanced biological phosphorus removal systems. It was shown that the standard deviation of measurements in each lab and the reproducibility between the labs was very good. Experimental results obtained by different laboratories using this analysis method can be compared. Sludge samples with PHB contents varying between 0.3 and 22.5 mg PHB/mg sludge were analysed. The gas chromatographic method allows for PHV, PH2MB and PH2MV analysis as well.

  3. Reduction in the mutagenicity of synthetic dyes by successive treatment with activated sludge and the ligninolytic fungus, Irpex lacteus. (United States)

    Malachová, Katerina; Pavlícková, Zuzana; Novotný, Cenek; Svobodová, Katerina; Lednická, Denisa; Musílková, Eva


    Synthetic dyes are released in wastewater from textile manufacturing plants, and many of these dyes are genotoxic. In the present study, the mutagenicity of azo, anthraquinone, and triphenyl methane dyes was investigated before and after successive biodegradation with activated sludge and the ligninolytic fungus, Irpex lacteus. Two biodegradation systems were used to reduce the genotoxicity of dyes that were not efficiently inactivated by activated sludge alone. Mutagenicity was monitored with the Salmonella reversion assay conducted with the base-pair substitution detector strains, TA100 and YG1042, and the frame-shift detector strains, TA98 and YG1041, with and without rat liver S9. All dyes except for Congo Red (CR) were mutagenic with S9 activation. Assays conducted with the dyes indicated that only the azo dye Reactive Orange 16 (RO16) was mutagenic in both TA98 and TA100. Methyl Red and Disperse Blue 3 (DB3) were mutagenic in TA98, YG1041 and YG1042, while Reactive Black 5 was mutagenic in YG1041 and YG1042. Remazol Brilliant Blue R (RBBR), Crystal violet (CV) and Bromophenol Blue (BPB) were mutagenic only in TA98, but the toxicity of the latter two dyes complicated the evaluation of their mutagenicity. CR was not mutagenic in any of the tester strains. Biodegradation studies conducted with RO16 and DB3 indicated that the two-step biodegradation process reduced the mutagenic potential of RO16 and DB3 to a greater extent than activated sludge alone; the mutagenicity of the two dyes was reduced by 95.2% and 77.8%, respectively, by the two-step process. These data indicate that the combined biodegradation process may be useful for reducing the mutagenicity associated with wastewater from textile factories that contain recalcitrant dyes.

  4. Effect of Volatile Fatty Acids and Trimethylamine on Nitrification in Activated Sludge

    DEFF Research Database (Denmark)

    Eilersen, Ann Marie; Henze, Mogens; Kløft, Lene


    The effect of volatile fatty acids and trimethylamine on the nitrification activity of activated sludge was studied in laboratory batch experiments. The critical concentration of inhibitor IK at which the activity ceases was determined by modelling. IK values for ammonia oxidation were found...... wastewater stripped of sulphide showed that volatile fatty acids and trimethylamine alone cannot account for the inhibition of the nitrification activity, indicating that other factors are also involved....

  5. Bacterial community analysis of activated sludge: an evaluation of four commonly used DNA extraction methods

    NARCIS (Netherlands)

    Vanysacker, L.; Declerck, S.A.J.; Hellemans, B.; De Meester, L.; Vankelecom, I.; Declerck, P.


    The effectiveness of three commercially available direct DNA isolation kits (Mobio, Fast, Qiagen) and one published direct DNA extraction protocol (Bead) for extracting bacterial DNA from different types of activated sludge was investigated and mutually compared. The DNA quantity and purity were det

  6. Simultaneous biological removal of sulfide and nitrate by autotrophic denitrification in an activated sludge system

    NARCIS (Netherlands)

    Manconi, I.; Carucci, A.; Lens, P.N.L.; Rossetti, S.


    The feasibility of an autotrophic denitrification process in an activated sludge reactor, using sulphide as the electron donor, was tested for simultaneous denitrification and sulphide removal. The reactor was operated at nitrate (N) to sulphide (S) ratios between 0.5 and 0.9 to evaluate their effec

  7. Immobilization study of biosorption of heavy metal ions onto activated sludge

    Institute of Scientific and Technical Information of China (English)

    WU Hai-suo; ZHANG Ai-qiang; WANG Lian-sheng


    Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10-100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH≤ 5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. The adsorption rate of immobilized pretreated activated sludge(PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40℃.Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS.

  8. Wastewater and Biomass Characterization for the Activated Sludge Model No. 2: Biological Phosphorus Removal

    DEFF Research Database (Denmark)

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


    The characterization of wastewater and biomass in relation to the Activated Sludge Model No. 2 is described. A new fraction of organic fermentable matter is needed. Phosphate accumulating organisms and their structural compounds polyphosphate and polyhydroxyalkanoate have to be included in the bi...

  9. Control and identification in activated sludge processes = Regeling en indentifikatie in aktief-slib processen

    NARCIS (Netherlands)

    Lukasse, L.


    This thesis is about control and identification in activated sludge processes (ASP's). The chapters in this thesis are divided in two parts. Part I deals with the development of the best feasible, close-to-optimal adaptive receding horizon optimal controller (RHOC) for N-removal in a continuously mi

  10. Bioremediation of heavy metal-contaminated effluent using optimized activated sludge bacteria (United States)

    Bestawy, Ebtesam El.; Helmy, Shacker; Hussien, Hany; Fahmy, Mohamed; Amer, Ranya


    Removal of heavy metals from contaminated domestic-industrial effluent using eight resistant indigenous bacteria isolated from acclimatized activated sludge was investigated. Molecular identification using 16S rDNA amplification revealed that all strains were Gram-negative among which two were resistant to each of copper, cadmium and cobalt while one was resistant to each of chromium and the heavy metal mixture. They were identified as Enterobacter sp. (Cu1), Enterobacter sp. (Cu2), Stenotrophomonas sp. (Cd1), Providencia sp. (Cd2), Chryseobacterium sp. (Co1), Comamonas sp. (Co2), Ochrobactrum sp. (Cr) and Delftia sp. (M1) according to their resistance pattern. Strains Cu1, Cd1, Co2 and Cr were able to resist 275 mg Cu/l, 320 mg Cd/l, 140 mg Co/l and 29 mg Cr/l respectively. The four resistant strains were used as a mixture to remove heavy metals (elevated concentrations) and reduce the organic load of wastewater effluent. Results revealed that using the proposed activated sludge with the resistant bacterial mixture was more efficient for heavy metal removal compared to the activated sludge alone. It is therefore recommended that the proposed activated sludge system augmented with the acclimatized strains is the best choice to ensure high treatment efficiency and performance under metal stresses especially when industrial effluents are involved.

  11. Mesophilic and thermophilic alkaline fermentation of waste activated sludge for hydrogen production: Focusing on homoacetogenesis

    DEFF Research Database (Denmark)

    Wan, Jingjing; Jing, Yuhang; Zhang, Shicheng;


    The present study compared the mesophilic and thermophilic alkaline fermentation of waste activated sludge (WAS) for hydrogen production with focus on homoacetogenesis, which mediated the consumption of H2 and CO2 for acetate production. Batch experiments showed that hydrogen yield of WAS increased...

  12. External Carbon Source Addition as a Means to Control an Activated Sludge Nutrient Removal Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens; Søeberg, Henrik;


    In alternating type activated sludge nutrient removal processes, the denitrification rate can be limited by the availability of readily-degradable carbon substrate. A control strategy is proposed by which an easily metabolizable COD source is added directly to that point in the process at which...

  13. Combined removal of sulfur compounds and nitrate by autotrophic denitrication in bioaugmented activated sludge system

    NARCIS (Netherlands)

    Manconi, I.; Carucci, A.; Lens, P.N.L.


    An autotrophic denitrification process using reduced sulfur compounds (thiosulfate and sulfide) as electron donor in an activated sludge system is proposed as an efficient and cost effective alternative to conventional heterotrophic denitrification for inorganic (or with low C/N ratio) wastewaters a

  14. Dosing of anaerobic granular sludge bioreactors with cobalt: Impact of cobalt retention on methanogenic activity

    KAUST Repository

    Fermoso, Fernando G.


    The effect of dosing a metal limited anaerobic sludge blanket (UASB) reactor with a metal pulse on the methanogenic activity of granular sludge has thus far not been successfully modeled. The prediction of this effect is crucial in order to optimize the strategy for metal dosage and to prevent unnecessary losses of resources. This paper describes the relation between the initial immobilization of cobalt in anaerobic granular sludge cobalt dosage into the reactor and the evolution of methanogenic activity during the subsequent weeks. An operationally defined parameter (A0· B0) was found to combine the amount of cobalt immobilized instantaneously upon the pulse (B0) and the amount of cobalt immobilized within the subsequent 24. h (A0). In contrast with the individual parameters A0 and B0, the parameter A0· B0 correlated significantly with the methanogenic activity of the sludge during the subsequent 16 or 35. days. This correlation between metal retention and activity evolution is a useful tool to implement trace metal dosing strategies for biofilm-based biotechnological processes. © 2010.

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

    NARCIS (Netherlands)

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


    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

  16. Biodegradation of pharmaceuticals in hospital wastewater by a hybrid biofilm and activated sludge system (Hybas)

    DEFF Research Database (Denmark)

    Escola Casas, Monica; Chhetri, Ravi Kumar; Ooi, Gordon Tze Hoong


    Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process, has been suggested as a possible solution for hospital wastewater treatment. HybasTM is a hyb...

  17. Start-up of anaerobic ammonia oxidation bioreactor with nitrifying activated sludge

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ping; LIN Feng-mei; HU Bao-lan; CHEN Jian-song


    The anaerobic ammonia oxidation(Anammox) bioreactor was successfully started up with the nitrifying activated sludge. After anaerobically operated for 105 d, the bioreactor reached a good performance with removal percentage of both ammonia and nitrite higher high efficiency and stability because it held a large amount of biomass in the bioreactor.

  18. Enhancing methane production from waste activated sludge using a novel indigenous iron activated peroxidation pre-treatment process. (United States)

    Zhou, Xu; Wang, Qilin; Jiang, Guangming


    Methane production from anaerobic digestion of waste activated sludge (WAS) is limited by the slow hydrolysis rate and/or poor methane potential of WAS. This study presents a novel pre-treatment strategy based on indigenous iron (in WAS) activated peroxidation to enhance methane production from WAS. Pre-treatment of WAS for 30 min at 50mg H2O2/g total solids (dry weight) and pH 2.0 (iron concentration in WAS was 7 mg/g TS) substantially enhanced WAS solubilization. Biochemical methane potential tests demonstrated that methane production was improved by 10% at a digestion time of 16d after incorporating the indigenous iron activated peroxidation pre-treatment. Model-based analysis indicated that indigenous iron activated peroxidation pre-treatment improved the methane potential by 13%, whereas the hydrolysis rate was not significantly affected. The economic analysis showed that the proposed pre-treatment method can save the cost by $112,000 per year in a treatment plant with a population equivalent of 300,000.

  19. Isolation and characterization of bacteriophage SPI1, which infects the activated-sludge-foaming bacterium Skermania piniformis. (United States)

    Dyson, Z A; Tucci, J; Seviour, R J; Petrovski, S


    Foaming in activated sludge plants is a worldwide problem commonly caused by proliferation of bacteria of the order Corynebacteriales. These include Skermania piniformis, a filamentous bacterium that has been documented to be a major cause of foaming globally, and particularly in Australian treatment plants. Phage SPI1 is the first phage that was isolated and shown to infect this organism. It targets seven of the nine strains of S. piniformis held in our culture collection, but none of the other 73 mycolata strains of different genera, mostly isolated from wastewater, against which it was tested. Phage SPI1 is a member of the family Siphoviridae and has a circularly permuted dsDNA genome of 55,748 bp with a G+C content of 67.8 mol %. It appears to be obligatorily lytic, with no evidence of genes related to a lysogenic mode of existence.

  20. Use of sewage sludge as secondary fuel in a cement plant: human health risks. (United States)

    Rovira, Joaquim; Mari, Montse; Nadal, Martí; Schuhmacher, Marta; Domingo, José L


    Since 2008, sewage sludge is being used as alternative fuel in a cement plant placed in Vallcarca (Catalonia, Spain). To evaluate the temporal trend of the environmental levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and a number of metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Tl, V, and Zn), as well as the potentially associated human health risks, samples of soil, herbage, and air were collected around the facility, after approximately one year of the permanent partial substitution of fuel. The temporal evolution of the pollutant levels was assessed by comparing the measured concentrations (2009) with those from samples collected in previous surveys (2003 and 2006) at the same sampling sites. The concentrations of PCDD/Fs in herbage and soil were 0.10 and 1.11 ng I-TEQ·kg⁻¹ dw, respectively, values very similar to those found in our previous surveys. For metals, although a clear tendency could not be observed, there were fluctuations through time. In this study, the levels of metals, which had not been analyzed in previous campaigns, were also determined in air, additionally to soil and vegetation. Airborne metal concentrations were similar to those found in other industrial areas worldwide. The human health risks for the population living around the cement plant were comparable to those obtained in previous studies, when petroleum coke was exclusively used as combustible, being in both cases tolerable according to the international standards.

  1. [Utilizing the wastewater treatment plant sludge for the production of eco-cement]. (United States)

    Lin, Yi-Ming; Zhou, Shao-Qi; Zhou, De-Jun; Wu, Yan-Yu


    The aim of this paper was to study the effect on cement property by using of municipal sewage as additive in the process of clinker burning. Based on the standard sample P. 042. 5 from cement plant, the properties of eco-cement samples adding municipal sewage to unit raw material by 0%, 0.50%, 1.00%, 1.50%, 2.00%, 2.50% respectively and the standard sample from the cement plant were compared. According to the analysis of X-ray diffraction, microstructure, the particles size determination material change, the setting time, specific surface area, leaching toxicity and strength of cement mortar of the cement, respectively, it showed that the strength of the productions were similar to the P. 042.5 standard sample. The metal ion concentrations of Al, Fe, Ba, Mn and Ti in clinkers and raw material decreased, the initial and setting time increased, as well as the strength of the paste within the curing time of 3 days decreased with the increase of municipal sewage ratio. However, after the curing of 7 days, the strength was similar to non-sludge-mortar or even higher.

  2. Composting rice straw with sewage sludge and compost effects on the soil-plant system. (United States)

    Roca-Pérez, L; Martínez, C; Marcilla, P; Boluda, R


    Composting organic residue is an interesting alternative to recycling waste as the compost obtained may be used as organic fertilizer. This study aims to assess the composting process of rice straw and sewage sludge on a pilot-scale, to evaluate both the quality of the composts obtained and the effects of applying such compost on soil properties and plant development in pot experiments. Two piles, with shredded and non-shredded rice straw, were composted as static piles with passive aeration. Throughout the composting process, a number of parameters were determined, e.g. colour, temperature, moisture, pH, electrical conductivity, organic matter, C/N ratio, humification index, cation exchange capacity, chemical oxygen demand, and germination index. Moreover, sandy and clayey soils were amended with different doses of mature compost and strewed with barley in pot experiments. The results show that compost made from shredded rice straw reached the temperatures required to maximise product sanitisation, and that the parameters indicating compost maturity were all positive; however, the humification index and NH(4) content were more selective. Therefore, using compost-amended soils at a dose of 34 Mg ha(-1) for sandy soil, and of 11 Mg ha(-1) for clayey soil improves soil properties and the growth of Hordeum vulgare plants. Under there conditions, the only limiting factor of agronomic compost utilisation was the increased soil salinity.

  3. Enhancement of anaerobic biohydrogen/methane production from cellulose using heat-treated activated sludge. (United States)

    Lay, C H; Chang, F Y; Chu, C Y; Chen, C C; Chi, Y C; Hsieh, T T; Huang, H H; Lin, C Y


    Anaerobic digestion is an effective technology to convert cellulosic wastes to methane and hydrogen. Heat-treatment is a well known method to inhibit hydrogen-consuming bacteria in using anaerobic mixed cultures for seeding. This study aims to investigate the effects of heat-treatment temperature and time on activated sludge for fermentative hydrogen production from alpha-cellulose by response surface methodology. Hydrogen and methane production was evaluated based on the production rate and yield (the ability of converting cellulose into hydrogen and methane) with heat-treated sludge as the seed at various temperatures (60-97 degrees C) and times (20-60 min). Batch experiments were conducted at 55 degrees C and initial pH of 8.0. The results indicate that hydrogen and methane production yields peaked at 4.3 mmol H2/g cellulose and 11.6 mmol CH4/g cellulose using the seed activated sludge that was thermally treated at 60 degrees C for 40 min. These parameter values are higher than those of no-treatment seed (HY 3.6 mmol H2/g cellulose and MY 10.4 mmol CH4/g cellulose). The maximum hydrogen production rate of 26.0 mmol H2/L/d and methane production rate of 23.2 mmol CH4/L/d were obtained for the seed activated sludge that was thermally treated at 70 degrees C for 50 min and 60 degrees C for 40 min, respectively.

  4. Bacteriophages of wastewater foaming-associated filamentous Gordonia reduce host levels in raw activated sludge (United States)

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


    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

  5. Activated sludge characterization through microscopy: A review on quantitative image analysis and chemometric techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Daniela P. [IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Amaral, A. Luís [IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Instituto Politécnico de Coimbra, ISEC, DEQB, Rua Pedro Nunes, Quinta da Nora, 3030-199 Coimbra (Portugal); Ferreira, Eugénio C., E-mail: [IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)


    Graphical abstract: -- Highlights: •Quantitative image analysis shows potential to monitor activated sludge systems. •Staining techniques increase the potential for detection of operational problems. •Chemometrics combined with quantitative image analysis is valuable for process monitoring. -- Abstract: In wastewater treatment processes, and particularly in activated sludge systems, efficiency is quite dependent on the operating conditions, and a number of problems may arise due to sludge structure and proliferation of specific microorganisms. In fact, bacterial communities and protozoa identification by microscopy inspection is already routinely employed in a considerable number of cases. Furthermore, quantitative image analysis techniques have been increasingly used throughout the years for the assessment of aggregates and filamentous bacteria properties. These procedures are able to provide an ever growing amount of data for wastewater treatment processes in which chemometric techniques can be a valuable tool. However, the determination of microbial communities’ properties remains a current challenge in spite of the great diversity of microscopy techniques applied. In this review, activated sludge characterization is discussed highlighting the aggregates structure and filamentous bacteria determination by image analysis on bright-field, phase-contrast, and fluorescence microscopy. An in-depth analysis is performed to summarize the many new findings that have been obtained, and future developments for these biological processes are further discussed.

  6. Bacteriophages of wastewater foaming-associated filamentous Gordonia reduce host levels in raw activated sludge. (United States)

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


    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.

  7. Diversity of Dominant Bacterial Taxa in Activated Sludge Promotes Functional Resistance following Toxic Shock Loading

    KAUST Repository

    Saikaly, Pascal


    Examining the relationship between biodiversity and functional stability (resistance and resilience) of activated sludge bacterial communities following disturbance is an important first step towards developing strategies for the design of robust biological wastewater treatment systems. This study investigates the relationship between functional resistance and biodiversity of dominant bacterial taxa by subjecting activated sludge samples, with different levels of biodiversity, to toxic shock loading with cupric sulfate (Cu[II]), 3,5-dichlorophenol (3,5-DCP), or 4-nitrophenol (4-NP). Respirometric batch experiments were performed to determine the functional resistance of activated sludge bacterial community to the three toxicants. Functional resistance was estimated as the 30 min IC50 or the concentration of toxicant that results in a 50% reduction in oxygen utilization rate compared to a referential state represented by a control receiving no toxicant. Biodiversity of dominant bacterial taxa was assessed using polymerase chain reaction-terminal restriction fragment length polymorphism (PCR-T-RFLP) targeting the 16S ribosomal RNA (16S rRNA) gene. Statistical analysis of 30 min IC50 values and PCR-T-RFLP data showed a significant positive correlation (P<0.05) between functional resistance and microbial diversity for each of the three toxicants tested. To our knowledge, this is the first study showing a positive correlation between biodiversity of dominant bacterial taxa in activated sludge and functional resistance. In this system, activated sludge bacterial communities with higher biodiversity are functionally more resistant to disturbance caused by toxic shock loading. © 2010 Springer Science+Business Media, LLC.

  8. Incorporation of inorganic material in anoxic/aerobic-activated sludge system mixed liquor. (United States)

    Wentzel, M C; Ubisi, M F; Lakay, M T; Ekama, G A


    In the bioreactor of the nitrification denitrification (ND)-activated sludge system, the mixed liquor is made up of organic and inorganic materials. In the current design procedures and simulation models, the influent wastewater characteristics and biological processes that influence the bioreactor mixed liquor organic solids (as volatile suspended solids, VSS, or COD) are explicitly included. However, the mixed liquor total suspended solids (TSS, i.e. organic + inorganic solids) are calculated simply from empirical ratios of VSS/TSS. The TSS concentration is fundamental in the design of secondary settling tanks and waste activated sludge disposal. Clearly, the empirical approach to obtaining an estimate for TSS is not satisfactory within the framework of a fundamentally based model. Accordingly, the incorporation of the inorganic material present in the influent wastewater into ND-activated sludge system mixed liquor was investigated. From an experimental investigation into the distribution of inorganics in the influent, mixed liquor and effluent of a laboratory-scale ND-activated sludge system, it was concluded inter alia that (i) of the total inorganic solids in the influent, only a small fraction (2.8-7.5%) is incorporated into the mixed liquor, (ii) most of the inorganics in the influent (mean 88%) and effluent (mean 98.5%) are in the dissolved form, the balance being particulate, and (iii) the influent and effluent inorganic dissolved solids concentrations are closely equal (mean effluent to influent ratio 100%). Further, a number of models were developed to quantify the mixed liquor inorganic, and, hence, total solids. From an evaluation of these models against the experimental data, it would appear that the best approach to model the incorporation of inorganics into the activated sludge mixed liquor is to follow the concepts and principles used to develop the existing models for organic materials. With this approach, reasonably close correlation between

  9. Application of the reliability analysis to the wastewater plant. Activated sludge pure oxygen system; Applicazione dell'analisi di affidabilita' alla depurazione delle acque. Impianto a fanghi attivi ad ossigeno puro

    Energy Technology Data Exchange (ETDEWEB)

    Corti, A. [Florence Univ., Florence (Italy). Dipt. di Energetica Sergio Stecco; Giagnoni, L. [Florence Univ., Florence (Italy). Dipt. di Energetica Sergio Stecco, Sez. Impianti e Tecnologie Industriali; Sirini, P. [Florence Univ., Florence (Italy). Dipt. di Ingegneria Civile


    The application of the reliability analysis to the wastewater plant is a valid and favorable instrument for the location of able managerial and/or structural participation to improve not only the emergency, but also the activity to obtain a product of optimal characteristics to several regimes (in the specific case the quality of effluent, the recovery of energy form the digestion processes, etc.) Moreover, the analysis techniques allow to indicate and to quantify the probability to create a crisis in to the system to the several steps it is subordinate during the own life utility. The wastewater process cannot be sure considered stationary. This variability can be controlled through one corrected appraisal in project and managerial activity equipping the system of great flexibility. In this way, the reliability analysis widens its range and it searches not only the single event able to produce a damage to the structure, but also that one is able to alter the final product. With this attempt, the classic techniques have been applied. Analysis, (Fault tree Analysis) to Bologna's wastewater treatment (pure oxygen system). [Italian] L'applicazione dell'analisi di affidabilita' agli impianti di depurazione si presenta come un valido e vantaggioso strumento per l'individuazione di interventi gestionali e/o strutturali capaci di migliorare non solo la sicurezza, ma anche l'attivita' depurativa al fine di ottenere un prodotto di caratteristiche ottimali ai vari regimi. Questo equiavale a dire, nel caso specifico, poter valutare la costanza dei termini di qualita' dell'effluente in uscita e del recupero di energia dai processi di digestione dei fanghi. Le tecniche di analisi di affidabilita' permettono di indicare e quantificare la probabilita' di eventi capaci di mettere in crisi l'attivita' stessa dell'impianto alle varie sollecitazioni a cui e' sottoposto durante la propria vita utile. Il

  10. Toxicity assessment of inorganic nanoparticles to acetoclastic and hydrogenotrophic methanogenic activity in anaerobic granular sludge. (United States)

    Gonzalez-Estrella, Jorge; Sierra-Alvarez, Reyes; Field, James A


    Release of engineered nanoparticles (NPs) to municipal wastewater from industrial and residential sources could impact biological systems in wastewater treatment plants. Methanogenic inhibition can cause failure of anaerobic waste(water) treatment. This study investigated the inhibitory effect of a wide array of inorganic NPs (Ag(0), Al₂O₃, CeO₂, Cu(0), CuO, Fe(0), Fe₂O₃, Mn₂O₃, SiO₂, TiO₂, and ZnO supplied up to 1500 mgL(-1)) to acetoclastic and hydrogenotrophic methanogenic activity of anaerobic granular sludge. Of all the NPs tested, only Cu(0) and ZnO caused severe methanogenic inhibition. The 50% inhibiting concentrations determined towards acetoclastic and hydrogenotrophic methanogens were 62 and 68 mgL(-1) for Cu(0) NP; and 87 and 250 mgL(-1) for ZnO NP, respectively. CuO NPs also caused inhibition of acetoclastic methanogens. Cu(2+) and Zn(2+) salts caused similar levels of inhibition as Cu(0) and ZnO NPs based on equilibrium soluble metal concentrations measured during the assays, suggesting that the toxicity was due to the release of metal ions by NP-corrosion. A commercial dispersant, Dispex, intended to increase NP stability did not affect the inhibitory impact of the NPs. The results taken as a whole suggest that Zn- and Cu-containing NPs can release metal ions that are inhibitory for methanogenesis.

  11. Activated sludge respirometry to assess solar detoxification of a metal finishing effluent

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Juanes, L.; Amat, A.M. [Departamento de Ingenieria Textil y Papelera, Escuela Politecnica Superior de Alcoy, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell s/n, E-03801 Alcoy (Spain); Arques, A. [Departamento de Ingenieria Textil y Papelera, Escuela Politecnica Superior de Alcoy, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell s/n, E-03801 Alcoy (Spain)], E-mail:; Bernabeu, A.; Silvestre, M.; Vicente, R. [Departamento de Ingenieria Textil y Papelera, Escuela Politecnica Superior de Alcoy, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell s/n, E-03801 Alcoy (Spain); Ano, E. [Departamento de Gestion e Innovacion, Area de producto y desarrollo sostenible, Asociacion de Investigacion de la Industria del Juguete, Conexas y Afines (AIJU), Avda. de la industria, 23, 03440 Ibi (Spain)], E-mail:


    Inhibition of the respiration of activated sludge has been tested as a convenient method to estimate toxicity of aqueous solutions containing copper and cyanide, such as metal finishing effluents; according to this method, an EC{sub 50} of 0.5 mg/l was determined for CN{sup -} and 3.0 mg/l for copper. Solar detoxification of cyanide-containing solutions was studied using TiO{sub 2}, but this process was unfavourable because of the inhibitory role that plays the copper ions present in real effluents on the oxidation of cyanide. On the other hand, the oxidative effect of hydrogen peroxide was greatly enhanced by Cu{sup 2+} and solar irradiation, as complete elimination of free and complexed cyanide could be accomplished, together with precipitation of copper, in experiments carried out at pilot plant scale with real metal finishing effluents. Under these conditions, total detoxification was achieved according to respirometric measurements although some remaining toxicity was determined by more sensitive Vibrio fischeri luminescent assay.

  12. Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works. (United States)

    Besançon, A; Le Corre, K S; Dotro, G; Jefferson, B


    This paper demonstrates that utilising a vertical flow (VF) wetland after a conventional activated sludge (CAS) delivers equivalent or better effluent quality to a membrane bioreactor (MBR) based on a side-by-side pilot trial. The CAS was operated under the solids retention times (SRT) of 6, 12, and 20 days, with the effluent from each pilot plant fed onto a soil aquifer treatment column to better understand their water reuse application potential. Results showed an upgraded CAS + VF system could deliver effluents with median values of 34 mgO2.L((-1)), 7 mg.L(-1) and 1.9 mg.L(-1) for organics, solids and ammonia nitrogen, respectively, which were statistically similar to those from the MBR. Water reuse standards were achieved by the upgraded system for most parameters, with the exception of total coliform removal. The upgraded system delivered superior metal removal when compared to the CAS. An economic analysis showed upgrading a CAS with a VF wetland was more favourable than investing in an MBR system for example works of 5000 and 50,000 population equivalents if the VF system was operated at hydraulic loading rates of 0.03 m.d(-1) and 0.08 m.d(-1), respectively. This was delivered for a tenth of the carbon footprint of the MBR treatment.

  13. Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers. (United States)

    Guo, Feng; Wang, Zhi-Ping; Yu, Ke; Zhang, T


    Foaming of activated sludge (AS) causes adverse impacts on wastewater treatment operation and hygiene. In this study, we investigated the microbial communities of foam, foaming AS and non-foaming AS in a sewage treatment plant via deep-sequencing of the taxonomic marker genes 16S rRNA and mycobacterial rpoB and a metagenomic approach. In addition to Actinobacteria, many genera (e.g., Clostridium XI, Arcobacter, Flavobacterium) were more abundant in the foam than in the AS. On the other hand, deep-sequencing of rpoB did not detect any obligate pathogenic mycobacteria in the foam. We found that unknown factors other than the abundance of Gordonia sp. could determine the foaming process, because abundance of the same species was stable before and after a foaming event over six months. More interestingly, although the dominant Gordonia foam former was the closest with G. amarae, it was identified as an undescribed Gordonia species by referring to the 16S rRNA gene, gyrB and, most convincingly, the reconstructed draft genome from metagenomic reads. Our results, based on metagenomics and deep sequencing, reveal that foams are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the foaming phenomenon in AS.

  14. Monitoring off-gas O2/CO2 to predict nitrification performance in activated sludge processes. (United States)

    Leu, Shao-Yuan; Libra, Judy A; Stenstrom, Michael K


    Nitrification/denitrification (NDN) processes are the most widely used technique to remove nitrogenous pollutants from municipal wastewater. The performance of nitrogen removal in the NDN process depends on the metabolism of nitrifying bacteria, and is dependent on adequate oxygen supply. Off-gas testing is a convenient and popular method for measuring oxygen transfer efficiency (OTE) under process conditions and can be performed in real-time. Since carbon dioxide is produced by carbonaceous oxidizing organism and not by nitrifiers, it should be possible to use the off-gas carbon dioxide mole fraction to estimate nitrification performance independently of the oxygen uptake rate (OUR) or OTE. This paper used off-gas data with a dynamic model to estimate nitrifying efficiency for various activated sludge process conditions. The relationship among nitrification, oxygen transfer, carbon dioxide production, and pH change was investigated. Experimental results of an online off-gas monitoring for a full-scale treatment plant were used to validate the model. The results showed measurable differences in OUR and carbon dioxide transfer rate (CTR) and the simulations successfully predicted the effluent ammonia by using the measured CO(2) and O(2) contents in off-gas as input signal. Carbon dioxide in the off-gas could be a useful technique to control aeration and to monitor nitrification rate.

  15. Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers (United States)

    Guo, Feng; Wang, Zhi-Ping; Yu, Ke; Zhang, T.


    Foaming of activated sludge (AS) causes adverse impacts on wastewater treatment operation and hygiene. In this study, we investigated the microbial communities of foam, foaming AS and non-foaming AS in a sewage treatment plant via deep-sequencing of the taxonomic marker genes 16S rRNA and mycobacterial rpoB and a metagenomic approach. In addition to Actinobacteria, many genera (e.g., Clostridium XI, Arcobacter, Flavobacterium) were more abundant in the foam than in the AS. On the other hand, deep-sequencing of rpoB did not detect any obligate pathogenic mycobacteria in the foam. We found that unknown factors other than the abundance of Gordonia sp. could determine the foaming process, because abundance of the same species was stable before and after a foaming event over six months. More interestingly, although the dominant Gordonia foam former was the closest with G. amarae, it was identified as an undescribed Gordonia species by referring to the 16S rRNA gene, gyrB and, most convincingly, the reconstructed draft genome from metagenomic reads. Our results, based on metagenomics and deep sequencing, reveal that foams are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the foaming phenomenon in AS.

  16. Assembly, start and operation of an activated sludge reactor for the industrial effluents treatment: physico chemical and biological parameters

    Directory of Open Access Journals (Sweden)

    Márcia Regina Assalin


    Full Text Available Although of the immense available bibliography regarding the activated sludge process, little it is found in relation to the basic procedure to be adopted to implant, to activate and to monitor a reactor of activated sludge in laboratory scales. This article describes the assembly, departure and operation of an activated sludge system, operating in continuous process, at a laboratory scale, to study effluents treatments, using as example, Kraft E1 pulp mill effluent. Factors as biodegradability of the effluent to be treated, stationary state of the reactor, conventional operation parameters as physical chemistry and biological parameters are presented.

  17. Optimization of ozonation process for the reduction of excess sludge production from activated sludge process of sago industry wastewater using central composite design. (United States)

    Subha, B; Muthukumar, M


    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.

  18. Paracetamol biodegradation by activated sludge and photocatalysis and its removal by a micelle-clay complex, activated charcoal, and reverse osmosis membranes. (United States)

    Karaman, Rafik; Khamis, Mustafa; Abbadi, Jehad; Amro, Ahmad; Qurie, Mohannad; Ayyad, Ibrahim; Ayyash, Fatima; Hamarsheh, Omar; Yaqmour, Reem; Nir, Shlomo; Bufo, Sabino A; Scrano, Laura; Lerman, Sofia; Gur-Reznik, Shirra; Dosoretz, Carlos G


    Kinetic studies on the stability of the pain killer paracetamol in Al-Quds activated sludge demonstrated that paracetamol underwent biodegradation within less than one month to furnish p-aminophenol in high yields. Characterizations of bacteria contained in Al-Quds sludge were accomplished. It was found that Pseudomonas aeruginosa is the bacterium most responsible for the biodegradation of paracetamol to p-aminophenol and hydroquinone. Batch adsorptions of paracetamol and its biodegradation product (p-aminophenol) by activated charcoal and a composite micelle (octadecyltrimethylammonium)-clay (montmorillonite) were determined at 25°C. Adsorption was adequately described by a Langmuir isotherm, and indicated better efficiency of removal by the micelle-clay complex. The ability of bench top reverse osmosis (RO) plant as well as advanced membrane pilot plant to remove paracetamol was also studied at different water matrixes to test the effect of organic matter composition. The results showed that at least 90% rejection was obtained by both plants. In addition, removal of paracetamol from RO brine was investigated by using photocatalytic processes; optimal conditions were found to be acidic or basic pH, in which paracetamol degraded in less than 5 min. Toxicity studies indicated that the effluent and brine were not toxic except for using extra low energy membrane which displayed a half maximal inhibitory concentration (IC-50) value of 80%.

  19. P-nitrophenol degradation by activated sludge attached on nonwovens. (United States)

    Bhatti, Zafar Iqbal; Toda, Haruko; Furukawa, Kenji


    p-Nitrophenol (PNP) is a toxic compound that enters the environment during manufacturing and processing of a variety of industrial products. This study demonstrates the use of inexpensive and durable nonwovens as a biomass retainer for the biological degradation of p-nitrophenol. An essential aspect of p-nitrophenol degradation was the cultivation of p-nitrophenol degrading biomass prior to its attachment on the nonwovens. Results of continuous flow experiments demonstrated that using the nonwovens could attain consistent high-rate p-nitrophenol degradation. 500 mg-PNP/L was completely degraded at a hydraulic retention time of 11 h. Specific and volumetric p-nitrophenol loading rates were determined to be 165 mg-PNP/g-MLSS/d and 1.6 g-PNP/L/d, respectively. Nitrite released from p-nitrophenol breakdown was not completely nitrified to nitrate. Characteristics of p-nitrophenol degrading sludge were also investigated.

  20. Feasibility study of green wastes composting with digested and dewatering sludge from municipal wastewater treatment plant in Iran


    Neamat Jaafarzadeh Haghighi Fard; Behnam Moradi; Mokhtar Abbasi; Rahman Alivar Babadi; Hossein Bahrani; Azadeh Mirzaie; Ahmad Zare Javid; Maryam Ravanbakhsh


    Background: Composting as a waste management technology is becoming more widespread. The purpose of this study was to assess the feasibility and to find the most effective composting process for the ratio of green waste, digested and dewatered sludge from Chonibieh wastewater treatment plant in the west region of Ahvaz. Methods: The composting time was 23 days and the evaluated parameters in this period of the study were organic carbon, total nitrogen, phosphorus, carbon to nitrogen ratio ...

  1. Composting plant of sewage sludges in Calles, Valencia (Spain); Planta de compostaje de fangos en la localidad de Calles (Valencia)

    Energy Technology Data Exchange (ETDEWEB)

    Morenilla Martinez, J. J.; Bernacer Bonora, I.; Jimenez Sanchez, J.; Zorrilla Soriano, F.; Manuelcandela, V.


    This article explains the operation of the composting plant of muds of residual waters in the location of Calles, in Valencia. Through the composting, the sludge is transformed in wet material. This process is developed by aerobic thermopile fermentation of the organic fraction of the muds. The composting is a biological process aerobic and thermopile by decomposition of organic waste in solid phase and in controlled conditions. (Author)

  2. Effect of Dissolved Oxygen on Microbial Population and Settling of Dairy Activated Sludge

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    T. Subramani


    Full Text Available The study was carried out to identify and study the settling characteristics of the dairy activated sludge. The causes and the control measure for the sludge bulking were studied. The activated sludge was generated by running a batch reactor of capacity of 10 liters for a θC of 10 days. It was operated until steady state conditions were reached. pH, DO, MLSS and COD were taken as the parameters. The settling studies were carried out for different MLSS concentrations ranging from 2g/L to 20g/L. The addition of Chlorine was selected as the control measure and was added for various doses such as 1 ml, 2 ml and 3 ml of Bleaching powder solution (1 ml of Bleaching powder solution contains 0.515 mg of Chlorine. Settling curves between interface height and time were observed before and after the addition of the Chlorine. From the settling curve the limiting solids flux were obtained. After the addition of Chlorine, there was a considerable increase in the settling velocity that improves the settling nature of the sludge. Area of Secondary settling tank was calculated from the modified solids flux method.

  3. Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability. (United States)

    Dwyer, Jason; Starrenburg, Daniel; Tait, Stephan; Barr, Keith; Batstone, Damien J; Lant, Paul


    Activated sludges are becoming more difficult to degrade in anaerobic digesters, due to the implementation of stricter nitrogen limits, longer sludge ages, and removal of primary sedimentation units. Thermal hydrolysis is a popular method to enhance degradability of long-age activated sludge, and involves pressure and heat treatment of the process fluid (150-160 degrees C saturated steam). However, as documented in this study, in a full-scale system, the use of thermal hydrolysis produces coloured, recalcitrant compounds that can have downstream impacts (e.g., failure of UV disinfection, and increased effluent nitrogen). The coloured compound formed during thermal hydrolysis was found to be melanoidins. These are coloured recalcitrant compounds produced by polymerisation of low molecular weight intermediates, such as carbohydrates and amino compounds at elevated temperature (Maillard reaction). By decreasing the THP operating temperature from 165 degrees C to 140 degrees C, THP effluent colour decreased from 12,677 mg-PtCo L(-1) to 3837 mg-PtCo L(-1). The change in THP operating temperature from 165 degrees C to 140 degrees C was shown to have no significant impact on anaerobic biodegradability of the sludge. The rate and extent of COD biodegradation remained largely unaffected by the temperature change with an average first order hydrolysis rate of 0.19 d(-1) and conversion extent of 0.43 g-COD(CH4)g-COD(-1).

  4. Biological treatment of synthetic wastewater containing 2,4 dichlorophenol (DCP) in an activated sludge unit. (United States)

    Kargi, Fikret; Eker, Serkan; Uygur, Ahmet


    Chlorophenol compounds present in many chemical industry wastewaters are resistant to biological degradation because of the toxic effects of such compounds on microorganisms. Synthetic wastewater containing different concentrations of 2,4 dichlorophenol (DCP) was subjected to biological treatment in an activated sludge unit. Effects of feed DCP concentration on COD, DCP, and toxicity removals and on sludge volume index were investigated at a constant sludge age of 10 days and hydraulic residence time (HRT) of 25 h. The Resazurin method based on dehydrogenase activity was used for assessment of toxicity for the feed and effluent wastewater. Percent COD, DCP, and toxicity removals decreased and the effluent COD, DCP, and toxicity levels increased with increasing feed DCP concentrations above 150 mgl(-1) because of inhibitory effects of DCP. Biomass concentration in the aeration tank decreased and the sludge volume index (SVI) increased with feed DCP concentrations above 150 mgl(-1) resulting in lower COD and DCP removal rates. The system should be operated at feed DCP concentrations of less than 150 mgl(-1) in order to obtain high COD, DCP, and toxicity removals.

  5. Association of naturally occurring radionuclides in sludges from Drinking Water Treatment Plants previously optimized for their removal. (United States)

    Baeza, A; Salas, A; Guillén, J; Muñoz-Serrano, A


    The raw water used in Drinking Water Treatment Plants (DWTPs) can present high values of naturally occurring radionuclides. In order to reduce this content, the routine working conditions of DWTPs were successfully modified. This meant that those radionuclides were accumulated in the sludges generated, whose radioactive content was frequently above the exemption levels. It therefore becomes necessary to assess the association of naturally occurring radionuclides in the sludges for their potential use as agricultural fertilizers. Two approaches were studied: (a) the effect of different sequential extraction methods applied to a selected sludge; and (b) the effect of the different contents of inorganic complexes dissolved in the input water on the composition of the sludges generated by two DWTPs with different origins of their input water. Uranium and radium were mainly associated with the carbonated and reducible fractions, while (210)Po and (228)Th were associated with the residual fraction. There were differences between the two speciation methods, but the order of bioavailable radionuclides was roughly the same: (226)Ra≈(234,238)U>(228)Th>(210)Po. The major inorganic complexes content, mainly carbonate, in the raw water affected the radionuclide association. The greater the carbonate content in the raw water, the greater was the association of uranium and radium with the carbonated and easily reducible fractions.

  6. Biodegradation of ibuprofen, diclofenac and carbamazepine in nitrifying activated sludge under 12 °C temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kruglova, Antonina; Ahlgren, Pia; Korhonen, Nasti; Rantanen, Pirjo; Mikola, Anna; Vahala, Riku


    Pharmaceuticals constitute a well-known group of emerging contaminants with an increasing significance in water pollution. This study focuses on three pharmaceuticals extensively used in Finland and which can be found in environmental waters: ibuprofen, diclofenac and carbamazepine. Biodegradation experiments were conducted in a full-scale Wastewater Treatment Plant (WWTP) and in laboratory-scale Sequencing Batch Reactors (SBRs). The SBRs were operated at 12 °C, with a sludge retention time (SRT) 10–12 d and organic loading rates (OLRs) of 0.17, 0.27 and 0.33 kg BOD{sub 7} m{sup -3}d{sup -1}. Ibuprofen was found to biodegrade up to 99%. The biodegradation rate constants (k{sub biol}) for ibuprofen were calculated for full-scale and laboratory processes as well as under different laboratory conditions and found to differ from 0.9 up to 5.0 l g{sub SS}{sup −1} d{sup −1}. Diclofenac demonstrated an unexpected immediate drop of concentration in three SBRs and partial recovery of the initial concentration in one of the reactors. High fluctuating in diclofenac concentration was presumably caused by removal of this compound under different concentrations of nitrites during development of nitrifying activated sludge. Carbamazepine showed no biodegradation in all the experiments. - Highlights: • The biodegradation of three pharmaceuticals examined under 12 °C conditions. • k{sub biol} constants for ibuprofen proposed for full-scale and laboratory-scale processes. • Influence of OLR on ibuprofen biodegradation was studied. • Removal followed by recovery of diclofenac detected in nitrifying activated sludge.

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

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


    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.

  8. Accumulation of Cr by plants in tanning sludge storage sites: opportunities for contamination bioindication and phytoremediation (United States)

    The lack of appropriate disposal strategies of tanning sludge (e.g., uncontrolled landfills and disposing sludge to open areas) has led to severe Cr pollution in waters and soils in many developing countries. Excessive Cr can be highly toxic to many living organisms and may damage the ecosystem. In ...

  9. Influence of secondary settling tank performance on suspended solids mass balance in activated sludge systems. (United States)

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


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

  10. A 1-year study of the activities of seven hydrolases in a communal wastewater treatment plant: trends and correlations. (United States)

    Kreutz, Jennifer Anna; Böckenhüser, Ina; Wacht, Marion; Fischer, Klaus


    The activities of seven hydrolytic enzymes (L-alanine aminopeptidase, esterase, α-and β-glucosidase, phosphomonoesterase, phosphodiesterase, sulfatase) were monitored during 1 year in parallel and serial treatment units of the biological stage of a communal wastewater treatment plant. The spatial homogeneity of enzyme activities was high (coefficients of variation  0.8) and highly significant (p plant effluent, dry matter content of activated sludge, and sludge volume, were found. The esterase activity was least correlated with other enzymes and often showed deviating dependencies on process parameters, raising questions concerning its appropriateness as a sum parameter for enzymatic and heterotrophic activity.

  11. Effect of nitrogen limitation on enrichment of activated sludge for PHA production. (United States)

    Basak, Bertan; Ince, Orhan; Artan, Nazik; Yagci, Nevin; Ince, Bahar Kasapgil


    Polyhydroxyalkanoates (PHA) are good candidates to plastics because of their material properties similar to conventional plastics and complete biodegradability. The use of activated sludge can be a cheaper alternative to pure cultures for PHA production. In this study, effect of nitrogen limitation during acclimatization period of biomass on production of polyhydroxyalkanoate was investigated. Activated sludge was selected in two sequencing batch reactors operated with and without nitrogen limitation. Batch tests were performed to examine polymer productions of activated sludges acclimatized to different nitrogen regimes. Responses of biomass to different organic loading rates, organic acids, and carbon to nitrogen (C/N) ratios were studied by determining specific polymer storage rate, polymer storage yield, and sludge polymer content of biomasses. Results obtained from batch experiments showed that concentrations of polymer accumulated by two different sludges increased directly with initial substrate concentration. Observed highest polymer yields for the biomasses enriched with and without nitrogen deficiency were 0.69 g COD PHA g(-1) COD S and 0.51 g COD PHA g(-1) COD S, and corresponding polymer contents of biomasses were 43.3% (g COD PHA g(-1) COD X) and 38.3% (g COD PHA g(-1) COD X), respectively. Polymer yields for both biomasses decreased with substrate shift however, biomass enriched with nitrogen deficiency adapted well to acetate-propionate mixture. The results presented in this study showed that polymer storage ability of biomass was improved more under dynamic conditions with nitrogen deficiency when compared to that without nitrogen deficiency. Limiting ammonia availability during batch experiments also caused higher polymer production by suppressing growth, as well as during enrichment of biomass.

  12. Behavior of metals, pathogen parasites, and indicator bacteria in sewage effluents during biological treatment by activated sludge. (United States)

    Tonani, K A A; Julião, F C; Trevilato, T M B; Takayanagui, A M M; Bocio, Ana; Domingo, Jose L; Segura-Muñoz, Susana I


    The purpose of this study was to evaluate the behavior of metals, pathogen parasites, and indicator bacteria in sewage effluents during biological treatment by activated sludge in a wastewater treatment plant in Ribeirão Preto (WTP-RP), Sao Paulo, Brazil. The evaluation was done during a period of 1 year. Results showed that metal concentrations in treated effluents decreased, reaching concentrations according to those established by national regulations. The activated sludge process at the WTP-RP promoted a partial removal of parasites considered as possible indicators according to the WHO guidelines. Reduction factors varied between 18.2% and 100% for agents such as Endolimax nana, Entamoeba coli, Entamoeba hystolitica, Giardia sp., Ancylostoma sp., Ascaris sp., Fasciola hepatica, and Strongyloides stercoralis. A removal was also observed in total and fecal coliforms quantification. The present study represents an initial evaluation of the chemical and microbiological removal capacity of the WTP-RP. The results should be of interest for the authorities responsible for the environmental health at municipal, regional, national, and international levels.

  13. Pilot and full scale applications of sulfur-based autotrophic denitrification process for nitrate removal from activated sludge process effluent. (United States)

    Sahinkaya, Erkan; Kilic, Adem; Duygulu, Bahadir


    Sulfur-based autotrophic denitrification of nitrified activated sludge process effluent was studied in pilot and full scale column bioreactors. Three identical pilot scale column bioreactors packed with varying sulfur/lime-stone ratios (1/1-3/1) were setup in a local wastewater treatment plant and the performances were compared under varying loading conditions for long-term operation. Complete denitrification was obtained in all pilot bioreactors even at nitrate loading of 10 mg NO3(-)-N/(L.h). When the temperature decreased to 10 °C during the winter time at loading of 18 mg NO3(-)-N/(L.h), denitrification efficiency decreased to 60-70% and the bioreactor with S/L ratio of 1/1 gave slightly better performance. A full scale sulfur-based autotrophic denitrification process with a S/L ratio of 1/1 was set up for the denitrification of an activated sludge process effluent with a flow rate of 40 m(3)/d. Almost complete denitrification was attained with a nitrate loading rate of 6.25 mg NO3(-)-N/(L.h).

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

    Energy Technology Data Exchange (ETDEWEB)

    Topalova, Y.; Dimkov, R. (Sofia Univ. (Bulgaria). Faculty of Biology); Kozuharov, D. (Bulgarian Academy of Science, Sofia (Bulgaria))


    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 essential 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.

  15. Bioavailability and plant accumulation of heavy metals and phosphorus in agricultural soils amended by long-term application of sewage sludge. (United States)

    Kidd, P S; Domínguez-Rodríguez, M J; Díez, J; Monterroso, C


    Amendment of agricultural soils with municipal sewage sludges provides a valuable source of plant nutrients and organic matter. Nevertheless, addition of heavy metals and risks of eutrophication continue to be of concern. Metal behaviour in soils and plant uptake are dependent on the nature of the metal, sludge/soil physico-chemical properties and plant species. A pot experiment was carried out to evaluate plant production and heavy metal uptake, soil heavy metal pools and bioavailability, and soil P pools and possible leaching losses, in agricultural soils amended with sewage sludge for at least 10 years (F20) compared to non-amended soils (control). Sewage sludge application increased soil pH, N, Olsen-extractable-P, DOC and exchangeable Ca, Mg and K concentrations. Total and EDTA-extractable soil concentrations of Cu and Zn were also significantly greater in F20, and soil metal (Cu, Mn and Zn) and P fractionation altered. Compared to the control, in F20 relative amounts of acid-extractable (Mn, Zn), reducible (Mn, Zn) and oxidisable (Cu, Zn) metal fractions were greater, and a dominance of inorganic P forms was observed. Analyses of F20 soil solutions highlighted risks of PO4 and Cu leaching. However, despite the observed increases in metal bioavailability sewage sludge applications did not lead to an increase in plant shoot concentrations (in wild plants or crop species). On the contrary, depending on the plant species, Mn and Zn tissue concentrations were within the deficiency level for most plants.

  16. Microbial Community Dynamics and Activity Link to Indigo Production from Indole in Bioaugmented Activated Sludge Systems.

    Directory of Open Access Journals (Sweden)

    Yuanyuan Qu

    Full Text Available Biosynthesis of the popular dyestuff indigo from indole has been comprehensively studied using pure cultures, but less has been done to characterize the indigo production by microbial communities. In our previous studies, a wild strain Comamonas sp. MQ was isolated from activated sludge and the recombinant Escherichia coli nagAc carrying the naphthalene dioxygenase gene (nag from strain MQ was constructed, both of which were capable of producing indigo from indole. Herein, three activated sludge systems, G1 (non-augmented control, G2 (augmented with Comamonas sp. MQ, and G3 (augmented with recombinant E. coli nagAc, were constructed to investigate indigo production. After 132-day operation, G3 produced the highest yields of indigo (99.5 ± 3.0 mg/l, followed by G2 (27.3 ± 1.3 mg/l and G1 (19.2 ± 1.2 mg/l. The microbial community dynamics and activities associated with indigo production were analyzed by Illumina Miseq sequencing of 16S rRNA gene amplicons. The inoculated strain MQ survived for at least 30 days, whereas E. coli nagAc was undetectable shortly after inoculation. Quantitative real-time PCR analysis suggested the abundance of naphthalene dioxygenase gene (nagAc from both inoculated strains was strongly correlated with indigo yields in early stages (0-30 days (P 0.10 of operation. Based on detrended correspondence analysis (DCA and dissimilarity test results, the communities underwent a noticeable shift during the operation. Among the four major genera (> 1% on average, the commonly reported indigo-producing populations Comamonas and Pseudomonas showed no positive relationship with indigo yields (P > 0.05 based on Pearson correlation test, while Alcaligenes and Aquamicrobium, rarely reported for indigo production, were positively correlated with indigo yields (P < 0.05. This study should provide new insights into our understanding of indigo bio-production by microbial communities.

  17. Improvement of anaerobic digestion of sludge

    Energy Technology Data Exchange (ETDEWEB)

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


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

  18. Methane production and microbial community structure for alkaline pretreated waste activated sludge. (United States)

    Sun, Rui; Xing, Defeng; Jia, Jianna; Zhou, Aijuan; Zhang, Lu; Ren, Nanqi


    Alkaline pretreatment was studied to analyze the influence on waste activated sludge (WAS) reduction, methane production and microbial community structure during anaerobic digestion. Methane production from alkaline pretreated sludge (A-WAS) (pH = 12) increased from 251.2 mL/Ld to 362.2 mL/Ld with the methane content of 68.7% compared to raw sludge (R-WAS). Sludge reduction had been improved, and volatile suspended solids (VSS) removal rate and protein reduction had increased by ∼ 10% and ∼ 35%, respectively. The bacterial and methanogenic communities were analyzed using 454 pyrosequencing and clone libraries of 16S rRNA gene. Remarkable shifts were observed in microbial community structures after alkaline pretreatment, especially for Archaea. The dominant methanogenic population changed from Methanosaeta for R-WAS to Methanosarcina for A-WAS. In addition to the enhancement of solubilization and hydrolysis of anaerobic digestion of WAS, alkaline pretreatment showed significant impacts on the enrichment and syntrophic interactions between microbial communities.

  19. Enhanced high-solids anaerobic digestion of waste activated sludge by the addition of scrap iron. (United States)

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


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

  20. Two proposals for pumping calculations of non–newtonian fluids, water treatment plants disposal sludges case

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    H. Gardea–Villegas


    Full Text Available This paper presents two ways to calculate the pumping power of non Newtonian fluids and especially yield pseudoplastics which are the kind of disposal fluids from Water Treatment Plants. Fluids called sludges. The proposals included here, are based in methods suggested by Levenspiel (1986 applicable to determine the performance of Bingham plastics and pseudoplastic fluids using a graphical approximation of the rheological behavior of these materials. This approach has the advantage that is appropriate to any kind of regime. Otherwise, Levenspiel underlines, that there is not yet a chart who relates the roughness coefficient with the Reynolds number for general plastics, so it is not possible by now to calculate the yield pseudoplastic fluid. Its calculation is the aim of this study. Levenspiel proposes an approach subject to the assessment of the project manager, and will therefore entail personal observations, with the limitations that this can cause. The results obtained by both propositions, are very similar. This is part of a doctorate study done by the author under the direction of Dr. Rafael B. Carmona in the Faculty of Engineering of the National Autonomous University of Mexico.

  1. Toward better understanding and feasibility of controlling greenhouse gas emissions from treatment of industrial wastewater with activated sludge. (United States)

    Chen, Wei-Hsiang; Yang, Jun-Hong; Yuan, Chung-Shin; Yang, Ying-Hsien


    Wastewater treatment plants (WWTPs) have been recognized as important sources for anthropogenic greenhouse gas (GHG) emission. The objective of the study was to thoroughly investigate a typical industrial WWTP in southern Taiwan in winter and summer which possesses the emission factors close to those reported values, with the analyses of emission factors, mass fluxes, fugacity, lab-scale in situ experiments, and impact assessment. The activated sludge was the important source