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Sample records for activated sludge nitrification

  1. Bioaugmentation to improve nitrification in activated sludge treatment.

    PubMed

    Leu, Shao-Yuan; Stenstrom, Michael K

    2010-06-01

    Bioaugmentation is a proposed technique to improve nutrient removal in municipal wastewater treatment. Compared with commonly used nitrification/denitrification (NDN) processes, bioaugmentation may be able to reduce tankage or land requirements. Many approaches for bioaugmentation have been developed, but few studies have compared the benefits among different approaches. This paper quantifies the effectiveness of bioaugmentation processes and investigates three major "onsite" bioaugmentation alternatives: 1) the parallel-plants approach, which uses acclimated biomass grown in a nitrifying "long-SRT" (sludge retention time) plant to augment a low-SRT treatment plant; 2) the enricher-reactor approach, which uses an offline reactor to produce the augmentation cultures; and 3) the enricher-reactor/return activated sludge (ER-RAS) approach, which grows enrichment culture in a reaeration reactor that receives a portion of the recycle activated sludge. Kinetic models were developed to simulate each approach, and the benefits of various approaches are presented on the same basis with controllable parameters, such as bioaugmentation levels, aeration tank volume, and temperatures. Examples were given to illustrate the potential benefits of bioaugmentation by upgrading a "carbon-only" wastewater treatment plant to nitrification. Simulation results suggested that all bioaugmentation approaches can decrease the minimum SRT for nitrification. The parallel-plants approach creates the highest concentration of biomass but may fail at too low temperature. The ER-RAS approach likely would be more useful at lower temperature and required less reactor volume; enricher-reactor approach would likely be more advantageous in the presence of inhibitory compound(s). PMID:20572460

  2. An Operations Manual for Achieving Nitrification in an Activated Sludge Plant.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    In Ontario, the attainment of nitrification (oxidation of ammonia) in activated sludge plants is receiving increased attention. Nitrification of waste water is a necessary requirement because it reduces plant discharge of nitrogenous oxygen demand and/or toxic ammonia. However, this new requirement will result in added responsibility for…

  3. Evaluation of the persistence of micropollutants through pure-oxygen activated sludge nitrification and denitrification

    USGS Publications Warehouse

    Levine, A.D.; Meyer, M.T.; Kish, G.

    2006-01-01

    The persistence of pharmaceuticals, hormones, and household and industrial chemicals through a pure-oxygen activated sludge, nitrification, denitrification wastewater treatment facility was evaluated. Of the 125 micropollutants that were tested in this study, 55 compounds were detected in the untreated wastewater, and 27 compounds were detected in the disinfected effluent. The persistent compounds included surfactants, fire-retardant chemicals, pesticides, fragrance compounds, hormones, and one pharmaceutical. Physical-chemical properties of micropollutants that affected partitioning onto wastewater solids included vapor pressure and octanol-water partition coefficients.

  4. Recovery of nitrification in cadmium-inhibited activated sludge system by bio-accelerators.

    PubMed

    Wang, Yue; Ji, Min; Zhao, Yingxin; Zhai, Hongyan

    2016-01-01

    Cadmium (Cd) is toxic to nitrifying bacteria, but current studies on recovery process in Cd-inhibited activated sludge system are limited, especially on intensify-recovery processes with developing and optimizing nontoxic bio-accelerators. In this study, bioactivity recovery effects were demonstrated with respect to effluent NH4(+)-N, NO2(-)-N, NO3(-)-N concentrations, specific oxygen uptake rates and cadmium distribution in five parallel SBRs. Results indicated that bioactivity of nitrifying bacteria was mainly inhibited by surface-bound Cd. Dosing biotin, l-aspartic acid and cytokinin simultaneously was the most effective. Linear chain, together with amide (NH) and carboxyl (COOH) groups, may be important factors in fast nitrification recovery process. In terms of dosage and dosing mode, six-multiple dosage of optimal mixture with dosing at each cycle evenly was the most effective and bioactivities of nitrifying bacteria could 100% recovered within 7days. The bio-accelerators and optimum usage can be potentially applied to cope with heavy metal shock-loading emergency situations. PMID:26587790

  5. Inhibition of the nitrification process in activated sludge by trivalent and hexavalent chromium, and partitioning of hexavalent chromium between sludge compartments.

    PubMed

    Novotnik, Breda; Zuliani, Tea; Ščančar, Janez; Milačič, Radmila

    2014-06-01

    The input of wastewater treatment plants (WWTPs) may contain high concentrations of Cr(III) and Cr(VI), which can affect nitrogen removal. In the present study the influence of different Cr(III) and Cr(VI) concentrations towards activated sludge nitrification was studied. To better understand the mechanisms of Cr(VI) toxicity, its reduction, adsorption and uptake in activated sludge was investigated in a batch growth system. Quantification of Cr(VI) was performed by speciated isotope dilution inductively coupled plasma mass spectrometry. It was found that Cr(VI) concentrations above 1.0 mg L(-1) and Cr(III) concentrations higher than 50 mg L(-1) negatively affected nitrification. Speciation studies indicated almost complete reduction of Cr(VI) after 24h of incubation when Cr(VI) concentrations were lower than 2.5 mg L(-1), whereas for Cr(VI) added to 5 mg L(-1) around 40% remained unreduced. The study of the partitioning of Cr in the activated sludge was performed by the addition of Cr(VI) in concentrations of 2.5 and 5.0 mg L(-1). Results revealed that Cr was allocated mainly within the intercellular compartments, whereas intracellular and adsorbed Cr represented less than 0.1% of the Cr sludge concentrations. Cr(VI) was reduced in all compartments, the most efficiently (about 94%) within the intracellular and intercellular fractions. The extent of reduction of adsorbed Cr was 92% and 80% for 2.5 and 5.0mg of Cr(VI) L(-1), respectively. The results of present investigation provide a new insight into the toxicity of Cr species towards activated sludge nitrification, which is of significant importance for the management of WWTPs in order to prevent them from inflows containing harmful Cr(VI) concentrations. PMID:24462082

  6. Activated Sludge.

    ERIC Educational Resources Information Center

    Saunders, F. Michael

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. This review covers: (1) activated sludge process; (2) process control; (3) oxygen uptake and transfer; (4) phosphorus removal; (5) nitrification; (6) industrial wastewater; and (7) aerobic digestion. A list of 136 references is also presented. (HM)

  7. Characteristics of pellets with immobilized activated sludge and its performance in increasing nitrification in sequencing batch reactors at low temperatures.

    PubMed

    Dong, Wenjie; Lu, Guang; Yan, Li; Zhang, Zhenjia; Zhang, Yalei

    2016-04-01

    Immobilized pellets obtained by means of entrapping activated sludge in waterborne polyurethane were successfully adapted in ammonium (NH4(+)-N) synthetic wastewater. Its physicochemical characteristics were determined using scanning electron microscope, pyrosequencing, and microelectrodes, and its influence on the nitrification process in sequencing batch reactors (SBRs) at low temperatures was evaluated. A large number of rod-shaped bacteria were observed on the surface of the immobilized pellet, in which Rudaea spp. (Xanthomonadaceae family) was an important bacterial component (23.44% of the total bacteria). The oxygen uptake rate of immobilized pellets reached 240.83±15.59mgO2/(L·hr), and the oxygen was primarily consumed by the bacteria on the pellet surfaces (0-600μm). The dosing of the pellets (30mL/L) into an SBR significantly improved the nitrification efficiency at low temperatures of 7-11°C, achieving an average NH4(+)-N removal of 84.09%, which is higher than the removal of 67.46% observed for the control group. PMID:27090712

  8. Artificial Intelligence for the Evaluation of Operational Parameters Influencing Nitrification and Nitrifiers in an Activated Sludge Process.

    PubMed

    Awolusi, Oluyemi Olatunji; Nasr, Mahmoud; Kumari, Sheena; Bux, Faizal

    2016-07-01

    Nitrification at a full-scale activated sludge plant treating municipal wastewater was monitored over a period of 237 days. A combination of fluorescent in situ hybridization (FISH) and quantitative real-time polymerase chain reaction (qPCR) were used for identifying and quantifying the dominant nitrifiers in the plant. Adaptive neuro-fuzzy inference system (ANFIS), Pearson's correlation coefficient, and quadratic models were employed in evaluating the plant operational conditions that influence the nitrification performance. The ammonia-oxidizing bacteria (AOB) abundance was within the range of 1.55 × 10(8)-1.65 × 10(10) copies L(-1), while Nitrobacter spp. and Nitrospira spp. were 9.32 × 10(9)-1.40 × 10(11) copies L(-1) and 2.39 × 10(9)-3.76 × 10(10) copies L(-1), respectively. Specific nitrification rate (qN) was significantly affected by temperature (r 0.726, p 0.002), hydraulic retention time (HRT) (r -0.651, p 0.009), and ammonia loading rate (ALR) (r 0.571, p 0.026). Additionally, AOB was considerably influenced by HRT (r -0.741, p 0.002) and temperature (r 0.517, p 0.048), while HRT negatively impacted Nitrospira spp. (r -0.627, p 0.012). A quadratic combination of HRT and food-to-microorganism (F/M) ratio also impacted qN (r (2) 0.50), AOB (r (2) 0.61), and Nitrospira spp. (r (2) 0.72), while Nitrobacter spp. was considerably influenced by a polynomial function of F/M ratio and temperature (r (2) 0.49). The study demonstrated that ANFIS could be used as a tool to describe the factors influencing nitrification process at full-scale wastewater treatment plants. PMID:26906468

  9. Enhancing nitrogen removal efficiency and reducing nitrate liquor recirculation ratio by improving simultaneous nitrification and denitrification in integrated fixed-film activated sludge (IFAS) process.

    PubMed

    Bai, Yang; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2016-01-01

    An integrated fixed-film activated sludge (IFAS) process (G1) and an activated sludge anoxic-oxic process (G2) were operated at nitrate liquor recirculation ratio (R) of 100, 200 and 300% to investigate the feasibility of enhancing nitrogen removal efficiency (RTN) and reducing R by improving simultaneous nitrification and denitrification (SND) in the IFAS process. The results showed that the effluent NH4(+)-N and total nitrogen (TN) of G1 at R of 200% were less than 1.5 and 14.5 mg/L, satisfying the Chinese discharge standard (NH4(+)-N < 5 mg/L; TN < 15 mg/L). However, the effluent NH4(+)-N and TN of G2 at R of 300% were higher than 8.5 and 15.3 mg/L. It indicated that better RTN could be achieved at a lower R in the IFAS process. The polymerase chain reaction-denaturing gradient gel electrophoresis results implied that nitrifiers and denitrifiers co-existed in one microbial community, facilitating the occurrence of SND in the aerobic reactor of G1, and the contribution of SND to TN removal efficiency ranged 15-19%, which was the main reason that the RTN was improved in the IFAS process. Therefore, the IFAS process was an effective method for improving RTN and reducing R. In practical application, this advantage of the IFAS process can decrease the electricity consumption for nitrate liquor recirculation flow, thereby saving operational costs. PMID:26901725

  10. Effect of sludge age on simultaneous nitrification and denitrification in membrane bioreactor.

    PubMed

    Hocaoglu, S Murat; Insel, G; Cokgor, E Ubay; Orhon, D

    2011-06-01

    This study evaluated the effect of sludge age on simultaneous nitrification and denitrification in a membrane bioreactor treating black water. A membrane bioreactor with no separate anoxic volume was operated at a sludge age of 20 days under low dissolved oxygen concentration of 0.1-0.2mg/L. Its performance was compared with the period when the sludge age was adjusted to 60 days. Floc size distribution, apparent viscosity, and nitrogen removal differed significantly, together with different biomass concentrations: nitrification was reduced to 40% while denitrification was almost complete. Modelling indicated that both nitrification and denitrification kinetics varied as a function of the sludge age. Calibrated values of half saturation coefficients were reduced when the sludge age was lowered to 20 days. Model simulation confirmed the validity of variable process kinetics for nitrogen removal, specifically set by the selected sludge age. PMID:21507621

  11. A new photo-activated sludge system for nitrification by an algal-bacterial consortium in a photo-bioreactor with biomass recycle.

    PubMed

    van der Steen, Peter; Rahsilawati, Kuntarini; Rada-Ariza, Angélica M; Lopez-Vazquez, Carlos M; Lens, Piet N L

    2015-01-01

    Wastewater treatment technologies requiring large areas may be less feasible in urbanizing regions of developing countries. Therefore, a new technology, named photo-activated sludge (PAS), was investigated to combine the advantages of regular activated sludge systems with those of algae ponds for the removal of ammonium. The PAS consisted of a mixed photo-bioreactor, continuously fed with BG-11 medium, adjusted to 66 mgN-NH4⁺/l. The reactor volume was 2 l, hydraulic retention time was 24 hours, with a depth of 8 cm, and continuous illumination at the water surface was 66 μmol PAR/m²/s (photosynthetically active radiation). Reactor effluent passed through a settler and settled biomass was returned to the reactor. A well settling biomass developed, that contained both algae and nitrifiers. Effluent contained 10 mgN-NH4⁺/L and 51 mgN-NOx⁻/L. Using a simplified model, the specific algae growth rate was estimated at about 0.62 day⁻¹, which was within the expected range. For nitrifiers (ammonia oxidizers), the specific growth rate was 0.11 day⁻¹, which was lower than reported for regular activated sludge. The in-situ photo-oxygenation process by algae contributed 82% of the oxygen input, whereas oxygen diffusion through the mixed surface provided the remaining 18%. The foreseen energy savings that a PAS system could achieve warrant further investigations with real wastewater. PMID:26204077

  12. Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

    PubMed

    Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

    2016-01-01

    Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--natural zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance. PMID:26358216

  13. Efficient COD removal and nitrification in an upflow microaerobic sludge blanket reactor for domestic wastewater.

    PubMed

    Zheng, Shaokui; Cui, Cancan

    2012-03-01

    The treatment performance of an upflow microaerobic sludge blanket reactor (UMSB) for synthetic domestic wastewater was investigated at two dissolved oxygen (DO) levels, 0.3-0.5 and 0.7-0.9 mg l(-1), focusing on nitrification performance. The higher DO level induced complete nitrification of ammonia nitrogen (NH(3)-N), achieving chemical oxygen demand and NH(3)-N removals of 97 and 92%, respectively. There were consistently significantly higher nitrate nitrogen (NO(3)-N) and nitrite nitrogen (NO(2)-N) levels in the effluent, with ~66% of newly-produced oxidised nitrogen as NO(2)-N. Despite the high nitrification efficiency, only about 23% of the removed NH(3)-N amount from the influent was ultimately transformed into oxidised nitrogen due to the simultaneous nitrification-denitrification. Sludge blanket development and granulation occurred simultaneously in the UMSB. PMID:22105554

  14. Using sludge fermentation liquid to improve wastewater short-cut nitrification-denitrification and denitrifying phosphorus removal via nitrite.

    PubMed

    Ji, Zhouying; Chen, Yinguang

    2010-12-01

    Wastewater biological nutrient removal (BNR) by short-cut nitrification-denitrification (SCND) and denitrifying phosphorus removal via nitrite (DPRN) has several advantages, such as organic carbon source saving. In this paper, a new method, i.e., by using waste activated sludge alkaline fermentation liquid as BNR carbon source, for simultaneously improving SCND and DPRN was reported. First, the performance of SCND and DPRN with sludge fermentation liquid as carbon source was compared with acetic acid, which was commonly used in literatures. Sludge fermentation liquid showed much higher nitrite accumulation during aerobic nitrification than acetic acid (81.8% versus 40.9%), and the former had significant anoxic denitrification and phosphorus uptake. The soluble phosphorus and total nitrogen removal efficiencies with sludge fermentation liquid were much higher than with acetic acid (97.6% against 73.4% and 98.7% versus 79.2%). Then the mechanisms for sludge fermentation liquid showed higher SCND and DPRN than acetic acid were investigated from the aspects of wastewater composition, microorganisms assayed by 16S rRNA gene clone library, and fluorescence in situ hybridization. More NO(2)(-)-N accumulated by the use of sludge fermentation liquid was attributed to be more humic acids in the influent, which inhibited nitrite oxidizing bacteria (NOB) more serious than ammonia oxidizing bacteria (AOB), and more AOB but less NOB were observed in the BNR system. The reasons for sludge fermentation liquid BNR system exhibiting greater short-cut denitrifying phosphorus removal were that there were less glycogen accumulating organisms and more phosphorus accumulating organisms and anoxic denitrifying phosphorus removal bacteria with higher nitrite reductase activity. PMID:21053972

  15. WASTE ACTIVATED SLUDGE PROCESSING

    EPA Science Inventory

    A study was made at pilot scale of a variety of processes for dewatering and stabilization of waste activated sludge from a pure oxygen activated sludge system. Processes evaluated included gravity thickening, dissolved air flotation thickening, basket centrifugation, scroll cent...

  16. Partial nitrification and denitrification of mature landfill leachate using a pilot-scale continuous activated sludge process at low dissolved oxygen.

    PubMed

    Chen, Zhenguo; Wang, Xiaojun; Yang, YongYuan; Mirino, Markus W; Yuan, Yanlei

    2016-10-01

    Controlling of low dissolved oxygen (DO) levels (0.1-0.5mg/L), a cost-effective strategy, was applied to a pilot-scale anoxic-oxic-oxic-anoxic process for partial nitrification and denitrification of mature landfill leachate. High ammonium removal efficiency, stable nitrite accumulation rate and total nitrogen removal efficiency was higher than 95.0%, 90.0% and 66.4%, respectively, implying potential application of this process for nitrogen removal of mature landfill leachate. Efficient nitrite accumulation in the first oxic reactor depended on low DO conditions and sufficient alkalinity. However, operational limit was mainly decided by actual hydraulic retention time (AHRT) of the first oxic reactor and appeared with AHRT less than 13.9h under DO of 0.3-0.5mg/L. High-throughput sequencing analysis demonstrated significant change of bacterial diversity in the first oxic reactor after a long-term operation and dominant bacteria genus Nitrosomonas was shown to be responsible for NH4(+)-N removal and nitrite accumulation under low DO levels. PMID:27403860

  17. Design of nutrient removal activated sludge systems.

    PubMed

    Manga, J; Ferrer, J; Seco, A; Garcia-Usach, F

    2003-01-01

    A mechanistic mathematical model for nutrient and organic matter removal was used to describe the behavior of a nitrification denitrification enhanced biological phosphorus removal (NDEBPR) system. This model was implemented in a user-friendly software DESASS (design and simulation of activated sludge systems). A 484-L pilot plant was operated to verify the model results. The pilot plant was operated for three years over three different sludge ages. The validity of the model was confirmed with data from the pilot plant. Also, the utility of DESASS as a valuable tool for designing NDEBPR systems was confirmed. PMID:12906279

  18. Nitrification treatment of swine wastewater with acclimated nitrifying sludge immobilized in polymer pellets

    SciTech Connect

    Vanotti, M.B.; Hunt, P.G.

    2000-04-01

    Nitrification of ammonia (NH{sub 4}{sup +}) is a critical component for improved systems of animal wastewater treatment. One of the most effective processes uses nitrifying microorganisms encapsulated in polymer resins. It is used in Japan in municipal wastewater treatment plants for higher nitrification rates, shorter hydraulic retention times (HRT), and lower aeration treatment cost. The authors evaluated whether this technology could be adapted for treatment of higher-strength lagoon swine wastewaters containing {approximately}230 mg NH{sub 4}-N/L and 195 mg BOD{sub 5}/L. A culture of acclimated lagoon nitrifying sludge (ALNS) was prepared from a nitrifying biofilm developed in an overland flow soil using fill-and-draw cultivation. The ALNS was successfully immobilized in 3- to 5-mm polyvinyl alcohol (PVA) polymer pellets by a PVA-freezing method. Swine wastewater was treated in aerated, suspended bioreactors with a 15% (w/v) pellet concentration using batch and continuous flow treatment. Alkalinity was supplemented with inorganic carbon to maintain the liquid pH within an optimum range (7.7--8.4). In batch treatment, only 14 h were needed for nitrification of NH{sub 4}{sup +}. Ammonia was nitrified readily, decreasing at a rate of 16.1 mg NH{sub 4}-N/L h. In contrast, it took 10 d for a control (no-pellets) aerated reactor to start nitrification; furthermore, 70% of the N was lost by air stripping. Without alkalinity supplements, the pH of the liquid fell to 6.0--6.2, and NH{sub 4}{sup +} oxidation stopped. In continuous flow treatment, nitrification efficiencies of 95% were obtained with NH{sub 4}{sup +} loading rates of 418 mg-N/L-reactor d (2.73 g-N/g-pellet d) and an HRT of 12 h. The rate of nitrification obtained with HRT of 4 h was 567 mg-N/L d. In all cases, the NH{sub 4}-N removed was entirely recovered in oxidized N forms. Nitrification rates obtained in this work were not greatly affected by high NH{sub 4}{sup +} or BOD concentration of swine

  19. Partial nitrification of sludge reject water by means of aerobic granulation.

    PubMed

    López-Palau, S; Pericas, A; Dosta, J; Mata-Álvarez, J

    2011-01-01

    Granular sludge formation was performed in a laboratory scale Sequencing Batch Reactor (SBR) fed with supernatant of anaerobic digestion of sewage sludge. This effluent was concentrated progressively in order to enhance biomass capacity without inhibiting it. During the first part of the study, ammonium nitrogen was converted to nitrate, so conventional nitrification took place. When a nitrogen load of 0.8 g N L(-1) d(-1) was treated, the effluent concentration of nitrite started to increase while the nitrate concentration decreased until it disappeared. So, partial nitrification was achieved. At the end of this study, a nitrogen load of 1.1 g N L(-1) d(-1) was treated obtaining an effluent with 50% ammonium and 50% nitrite. The volatile suspended solids concentration in the reactor reached 10 g VSS L(-1). At this point the granule morphology was quite round and no filamentous bacteria was observed. The Feret's diameter was in the range between 1 and 6 mm with an average value of 4.5 mm. Roundness value was all the time higher than 0.7. Granule density increased during the experimental period, obtaining a final value of 7.0 g L(-1). PMID:22020486

  20. Chronic impact of tetracycline on nitrification kinetics and the activity of enriched nitrifying microbial culture.

    PubMed

    Katipoglu-Yazan, Tugce; Merlin, Christophe; Pons, Marie-Noëlle; Ubay-Cokgor, Emine; Orhon, Derin

    2015-04-01

    This study evaluated the chronic impact of tetracycline on biomass with enriched nitrifying community sustained in a lab-scale activated sludge system. For this purpose, a fill and draw reactor fed with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia was sustained at a sludge age of 15 days. At steady-state, the reactor operation was continued with a daily tetracycline dosing of 50 mg/L for more than 40 days, with periodic monitoring of the microbial composition, the nitrifying bacteria abundance, as well as the amoA and 16S rRNA gene activity, using molecular techniques. Changes in the kinetics of nitrification were quantified by modelling concentration profiles of major nitrogen fractions and oxygen uptake rate profiles derived from parallel batch experiments. Activated sludge modeling results indicated inhibitory impact of tetracycline on the growth of nitrifiers with a significant increase of the half saturation coefficients in corresponding rate equations. Tetracycline also inactivated biomass components of the enriched culture at a gradually increasing rate with time of exposure, leading to total collapse of nitrification. Molecular analyses revealed significant changes in the composition of the microbial community throughout the observation period. They also showed that continuous exposure to tetracycline inflicted significant reduction in amoA mRNA and 16S rRNA levels directly affecting nitrification. The chronic impact was much more pronounced on the ammonia oxidizing bacteria (AOB) community. These observations explained the basis of numerical changes identified in the growth kinetics of nitrifiers under stress conditions. PMID:25616640

  1. Ammonium adsorption in aerobic granular sludge, activated sludge and anammox granules.

    PubMed

    Bassin, J P; Pronk, M; Kraan, R; Kleerebezem, R; van Loosdrecht, M C M

    2011-10-15

    The ammonium adsorption properties of aerobic granular sludge, activated sludge and anammox granules have been investigated. During operation of a pilot-scale aerobic granular sludge reactor, a positive relation between the influent ammonium concentration and the ammonium adsorbed was observed. Aerobic granular sludge exhibited much higher adsorption capacity compared to activated sludge and anammox granules. At an equilibrium ammonium concentration of 30 mg N/L, adsorption obtained with activated sludge and anammox granules was around 0.2 mg NH4-N/g VSS, while aerobic granular sludge from lab- and pilot-scale exhibited an adsorption of 1.7 and 0.9 mg NH4-N/g VSS, respectively. No difference in the ammonium adsorption was observed in lab-scale reactors operated at different temperatures (20 and 30 °C). In a lab-scale reactor fed with saline wastewater, we observed that the amount of ammonium adsorbed considerably decreased when the salt concentration increased. The results indicate that adsorption or better ion exchange of ammonium should be incorporated into models for nitrification/denitrification, certainly when aerobic granular sludge is used. PMID:21840028

  2. [Effects of salinity on N2O production during nitrification using aerobic granular sludge].

    PubMed

    Wang, Shan-Shan; iang, Hong; Gao, Da-Wen

    2014-11-01

    An aerobic SBR biological wastewater treatment system was adopted to measure the N2O production and nitrogen removal using aerobic granular sludge nitrification process under 0, 5, 10 g x L(-1) salinity conditions. The results showed that the N2O production increased with the increase of salinity concentration. At three salinity levels (0, 5, 10 g x L(-1)), the dissolved N2O production was 1.21, 8.99, 24.81 mg x m(-3), respectively, and the released N2O was 0.95, 3.46, 16.45 mg x m(-3), respectively. The N2O release rates at the 5 g x L(-1) and 10 g x L(-1) salinity levels were 3.6 and 17.4 times as high as that at the 0 g x L(-1) salinity level. Under various salinity conditions both the dissolved and releasing state N2O production first increased and then decreased, and the dissolved N2O production was greater than that in the releasing state. In addition, when the salinity was low (less than 5 g x L(-1)), the NH4(+)-N removal rate was less affected and almost the same with the condition of 0 g x L(-1), both over 98%. When the salinity was increased to 10 g x L(-1), the NH4(+)-N removal rate dropped to 70%. Thus, increasing the salinity of wastewater not only affected the system nitrogen removal rate but also increased the amount of N2O production. PMID:25639101

  3. Heterotrophic nitrification and aerobic denitrification of high-strength ammonium in anaerobically digested sludge by Alcaligenes faecalis strain No. 4.

    PubMed

    Shoda, Makoto; Ishikawa, Yoichi

    2014-06-01

    Alcaligenes faecalis strain No. 4 which is capable of heterogeneous nitrification and aerobic denitrification, was used to remove high-strength ammonium (approximately 1 g NH4(+)-N/l) from digested sludge, the product of an anaerobic digestion reactor, in which methane was produced from excess municipal sewage sludge. Repeated batch operations were conducted at 20°C and 30°C for 550 h, using a jar fermentor. The removal ratios of high-strength ammonium reached 90-100% within 24 h, and the average ammonium removal rate was 2.9 kg-N/m(3)/day, more than 200 times higher than that in conventional nitrification-denitrification processes. During these operations, the cell density was maintained at 10(8)-10(9) cells of A. faecalis strain No. 4/ml. At 3% NaCl in the digested sludge, strain No. 4 exhibited an ammonium removal rate of 3 kg-N/m(3)/day. PMID:24411668

  4. Simultaneous nitrification and denitrification by EPSs in aerobic granular sludge enhanced nitrogen removal of ammonium-nitrogen-rich wastewater.

    PubMed

    Yan, Lilong; Zhang, Shaoliang; Hao, Guoxin; Zhang, Xiaolei; Ren, Yuan; Wen, Yan; Guo, Yihan; Zhang, Ying

    2016-02-01

    In this study, role of extracellular polymeric substances (EPSs) in enhancing nitrogen-removal from ammonium-nitrogen-rich wastewater using aerobic granular sludge (AGS) technology were analyzed. AGS enabled ammonium oxidation and denitrification to occur simultaneously. Air stripping and simultaneous nitrification-denitrification contributed to total-nitrogen removal. Clone-library analysis revealed that close relatives of Nitrosomonas eutropha and heterotrophic denitrifiers were dominant in the AGS, whereas anammox bacteria were not detected. EPSs adsorption of ammonium, nitrite, and nitrate nitrogen results in improved removal of nitrogen in batch experiments. PMID:26706722

  5. Advanced phosphorus recovery using a novel SBR system with granular sludge in simultaneous nitrification, denitrification and phosphorus removal process.

    PubMed

    Lu, Yong-Ze; Wang, Hou-Feng; Kotsopoulos, Thomas A; Zeng, Raymond J

    2016-05-01

    In this study, a novel process for phosphorus (P) recovery without excess sludge production from granular sludge in simultaneous nitrification-denitrification and P removal (SNDPR) system is presented. Aerobic microbial granules were successfully cultivated in an alternating aerobic-anaerobic sequencing batch reactor (SBR) for removing P and nitrogen (N). Dense and stable granular sludge was created, and the SBR system showed good performance in terms of P and N removal. The removal efficiency was approximately 65.22 % for N, and P was completely removed under stable operating conditions. Afterward, new operating conditions were applied in order to enhance P recovering without excess sludge production. The initial SBR system was equipped with a batch reactor and a non-woven cloth filter, and 1.37 g of CH3COONa·3H2O was added to the batch reactor after mixing it with 1 L of sludge derived from the SBR reactor to enhance P release in the liquid fraction, this comprises the new system configuration. Under the new operating conditions, 93.19 % of the P contained in wastewater was released in the liquid fraction as concentrated orthophosphate from part of granular sludge. This amount of P could be efficiently recovered in the form of struvite. Meanwhile, a deterioration of the denitrification efficiency was observed and the granules were disintegrated into smaller particles. The biomass concentration in the system increased firstly and then maintained at 4.0 ± 0.15 gVSS/L afterward. These results indicate that this P recovery operating (PRO) mode is a promising method to recover P in a SNDPR system with granular sludge. In addition, new insights into the granule transformation when confronted with high chemical oxygen demand (COD) load were provided. PMID:26728017

  6. Biomass characteristics and simultaneous nitrification-denitrification under long sludge retention time in an integrated reactor treating rural domestic sewage.

    PubMed

    Gong, Lingxiao; Jun, Li; Yang, Qing; Wang, Shuying; Ma, Bin; Peng, Yongzhen

    2012-09-01

    In this work, a novel integrated reactor incorporating anoxic fixed bed biofilm reactor (FBBR), oxic moving bed biofilm reactor (MBBR) and settler sequentially was proposed for nitrogen removal from rural domestic sewage. For purposes of achieving high efficiency, low costs and easy maintenance, biomass characteristics and simultaneous nitrification-denitrification (SND) were investigated under long sludge retention time during a 149-day period. The results showed that enhanced SND with proportions of 37.7-42.2% tapped the reactor potentials of efficiency and economy both, despite of C/N ratio of 2.5-4.0 in influent. TN was removed averagely by 69.3% at least, even under internal recycling ratio of 200% and less proportions of biomass assimilation (<3%). Consequently, lower internal recycle and intermittent wasted sludge discharge were feasible to save costs, together with cancellations of sludge return and anoxic stir. Furthermore, biomass with low observed heterotrophic yields (0.053 ± 0.035 g VSS/g COD) and VSS/TSS ratio (<0.55) in MBBR, simplified wasted sludge disposal. PMID:22750493

  7. Characteristics of extracellular polymeric substances from sludge and biofilm in a simultaneous nitrification and denitrification system under high salinity stress.

    PubMed

    Zhao, Linting; She, Zonglian; Jin, Chunji; Yang, Shiying; Guo, Liang; Zhao, Yangguo; Gao, Mengchun

    2016-09-01

    The composition and distribution of extracellular polymeric substance (EPS) both from suspended sludge and attached biofilm were investigated in a simultaneous nitrification and denitrification (SND) system with the increase of the salinity from 1.0 to 3.0 %. Fourier-transform infrared (FTIR) spectroscopy and three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy were used to examine proteins (PN), polysaccharides (PS) and humic substances (HS) present in EPS. High total nitrogen removal (above 83.9 %) via SND was obtained in the salinity range of 1.0-2.5 %. Total EPS in the sludge increased from 150.2 to 200.6 mg/gVSS with the increase of salinity from 1.0 to 3.0 %, whereas the corresponding values in the biofilm achieved the maximum of 288.6 mg/g VSS at 2.0 % salinity. Dominant composition of EPS was detected as HS in both sludge and biofilm, having the percentages of 50.6-68.6 and 41.1-69.9 % in total EPS, respectively. Both PN and PS contents in soluble EPS (S-EPS), loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) of sludge and biofilm increased with the increased salinity. The FTIR spectrum and 3D-EEM fluorescence spectroscopy of S-EPS, LB-EPS and TB-EPS in the sludge and biofilm showed the changes of functional groups and conformations of the compositions in EPS with the increase of salinity. The results demonstrated that the characteristics of EPS varied from sludge to biofilm. The obtained results could provide a better understanding of the salinity effect on the EPS characteristics in a SND system. PMID:27126502

  8. Impacts of addition of natural zeolite or a nitrification inhibitor on antibiotic resistance genes during sludge composting.

    PubMed

    Zhang, Junya; Chen, Meixue; Sui, Qianwen; Tong, Juan; Jiang, Chao; Lu, Xueting; Zhang, Yuxiu; Wei, Yuansong

    2016-03-15

    Composting is commonly used for the treatment and resource utilization of sewage sludge, and natural zeolite and nitrification inhibitors can be used for nitrogen conservation during sludge composting, while their impacts on ARGs control are still unclear. Therefore, three lab-scale composting reactors, A (the control), B (natural zeolite addition) and C (nitrification inhibitor addition of 3,4-dimethylpyrazole phosphate, DMPP), were established. The impacts of natural zeolite and DMPP on the levels of ARGs were investigated, as were the roles that heavy metals, mobile genetic elements (MGEs) and the bacterial community play in ARGs evolution. The results showed that total ARGs copies were enriched 2.04 and 1.95 times in reactors A and C, respectively, but were reduced by 1.5% in reactor B due to the reduction of conjugation and co-selection of heavy metals caused by natural zeolite. Although some ARGs (blaCTX-M, blaTEM, ermB, ereA and tetW) were reduced by 0.3-2 logs, others (ermF, sulI, sulII, tetG, tetX, mefA and aac(6')-Ib-cr) increased by 0.3-1.3 logs after sludge composting. Although the contributors for the ARGs profiles in different stages were quite different, the results of a partial redundancy analysis, Mantel test and Procrustes analysis showed that the bacterial community was the main contributor to the changes in ARGs compared to MGEs and heavy metals. Network analysis determined the potential host bacteria for various ARGs and further confirmed our results. PMID:26808292

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

    SciTech Connect

    Maranon, E. . E-mail: emara@uniovi.es; Castrillon, L.; Fernandez, Y.; Fernandez, E.

    2006-07-01

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

  10. [Biodiversity and Function Analyses of BIOLAK Activated Sludge Metagenome].

    PubMed

    Tian, Mei; Liu, Han-hu; Shen, Xin; Zhao, Fang-qing; Chen, Shuai; Yao, Yong-jia

    2015-05-01

    The BIOLAK is a multi-stage activated sludge process, which has been successfully promoted worldwide. However, the biological community and function of the BIOLAK activated sludge ( the core component in the process) have not been reported so far. In this study, taking Lianyungang Dapu Industrial Zone WWTP as an example, a large-scale metagenomic data (428 588 high-quality DNA sequences) of the BIOLAK activated sludge were obtained by means of a new generation of high-throughput sequencing technology. Amazing biodiversity was revealed in the BIOLAK activated sludge, which included 47 phyla, 872 genera and 1351 species. There were 33 phyla identified in the Bacteria domain (289 933 sequences). Proteohacteria was the most abundant phylum (62.54%), followed by Bacteroidetes (11.29%), Nitrospirae ( 5. 65%) and Planctomycetes (4.79%), suggesting that these groups played a key role in the BIOLAK wastewater treatment system. Among the 748 bacterial genera, Nitrospira (5.60%) was the most prevalent genus, which was a key group in the nitrogen cycle. Followed by Gemmatimonas (2.45%), which was an important genus in the biological phosphorus removal process. In Archaea domain (1019 sequences), three phyla and 39 genera were detected. In Eukaryota domain (1055 sequences), 60 genera and 10 phyla were identified, among which Ciliophora was the largest phylum (257 sequences). Meanwhile, 448 viral sequences were detected in the BIOLAK sludge metagenome, which were dominated by bacteriophages. The proportions of nitrogen, aromatic compounds and phosphorus metabolism in the BIOLAK sludge were 2.50%, 2.28% and 1.56%, respectively, which were higher than those in the sludge of United States and Australia. Among four processes of nitrogen metabolism, denitrification-related genes were most abundant (80.81%), followed by ammonification (12.78%), nitrification,(4.38%) and nitrogen fixation (2.04%). In conclusion, the BIOLAK activated sludge had amazing biodiversity, meanwhile

  11. Rapid start-up and microbial characteristics of partial nitrification granular sludge treating domestic sewage at room temperature.

    PubMed

    Liang, Yuhai; Li, Dong; Zeng, Huiping; Zhang, Cuidan; Zhang, Jie

    2015-11-01

    The successful suppression of nitrite-oxidizing bacteria in the partial nitrification (PN) stage was the main challenge for the application of autotrophic nitrogen removal process treating mainstream sewage. In this study, two identical PN granular reactors (P1 and P2) were rapid started-up using the simultaneous PN and granulation strategy, for treating the domestic sewage. P1 was seeded with 30% PN granular sludge to induce nucleation, in which the granule size achieved to more than 400μm in 12d, with ammonia oxidation rate and nitrite accumulation rate of 80% and 95%, respectively, while P2 realized granulation in 42d. The presence of organic matters and specific structure of granules were profitable for the stability of PN for treating sewage with low ammonia. High-throughput pyrosequencing results indicated the biodiversity of both reactors decreased after start-up, and Nitrosomonas was the predominant specie of aerobic ammonia-oxidizing bacteria in PN granular sludge. PMID:26271439

  12. Protein extraction from activated sludge.

    PubMed

    Denecke, M

    2006-01-01

    Two methods for the separation of protein originating from activated sludge were compared. In one method, the total protein was isolated out of the activated sludge (crude extract). These samples included all dissolved proteins originating from the bacterial cells and biofilm made up of extracellular polymeric substances (EPS). Every time polyacrylamide gel electrophoresis (PAGE) was done, the protein bands from samples of crude extract were covered by polymeric substances including carbohydrates, uronic acids or humic compounds. Using the immunoblot technique it was possible to demonstrate the presence of the heat shock protein HSP70 in crude extracts of activated sludge. The comparison of protein fingerprints required that clear and distinct bands appear on the PAGE analysis. To this end, a procedure to separates bacterial cells from the EPS was developed. Bacterial cells were separated by incubation with EDTA and subsequent filtration. The isolated cells were directly incubated in a sample buffer. PMID:16898150

  13. Biodegradability of wastewater and activated sludge organics in anaerobic digestion.

    PubMed

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

    2014-06-01

    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

  14. FRUIT CANNERY WASTE ACTIVATED SLUDGE AS A CATTLE FEED INGREDIENT

    EPA Science Inventory

    The feasibility of sludge disposal, from a fruit processing waste activated sludge treatment system, by dewatering and using the dewatered biological sludge solids as cattle feed was evaluated by Snokist Growers at Yakima, Washington. Dewatering of the biological sludge utilizing...

  15. Ammonia-oxidising bacteria not archaea dominate nitrification activity in semi-arid agricultural soil

    NASA Astrophysics Data System (ADS)

    Banning, Natasha C.; Maccarone, Linda D.; Fisk, Louise M.; Murphy, Daniel V.

    2015-06-01

    Ammonia-oxidising archaea (AOA) and bacteria (AOB) are responsible for the rate limiting step in nitrification; a key nitrogen (N) loss pathway in agricultural systems. Dominance of AOA relative to AOB in the amoA gene pool has been reported in many ecosystems, although their relative contributions to nitrification activity are less clear. Here we examined the distribution of AOA and AOB with depth in semi-arid agricultural soils in which soil organic matter content or pH had been altered, and related their distribution to gross nitrification rates. Soil depth had a significant effect on gene abundances, irrespective of management history. Contrary to reports of AOA dominance in soils elsewhere, AOA gene copy numbers were four-fold lower than AOB in the surface (0-10 cm). AOA gene abundance increased with depth while AOB decreased, and sub-soil abundances were approximately equal (10-90 cm). The depth profile of total archaea did not mirror that of AOA, indicating the likely presence of archaea without nitrification capacity in the surface. Gross nitrification rates declined significantly with depth and were positively correlated to AOB but negatively correlated to AOA gene abundances. We conclude that AOB are most likely responsible for regulating nitrification in these semi-arid soils.

  16. Ammonia-oxidising bacteria not archaea dominate nitrification activity in semi-arid agricultural soil

    PubMed Central

    Banning, Natasha C.; Maccarone, Linda D.; Fisk, Louise M.; Murphy, Daniel V.

    2015-01-01

    Ammonia-oxidising archaea (AOA) and bacteria (AOB) are responsible for the rate limiting step in nitrification; a key nitrogen (N) loss pathway in agricultural systems. Dominance of AOA relative to AOB in the amoA gene pool has been reported in many ecosystems, although their relative contributions to nitrification activity are less clear. Here we examined the distribution of AOA and AOB with depth in semi-arid agricultural soils in which soil organic matter content or pH had been altered, and related their distribution to gross nitrification rates. Soil depth had a significant effect on gene abundances, irrespective of management history. Contrary to reports of AOA dominance in soils elsewhere, AOA gene copy numbers were four-fold lower than AOB in the surface (0–10 cm). AOA gene abundance increased with depth while AOB decreased, and sub-soil abundances were approximately equal (10–90 cm). The depth profile of total archaea did not mirror that of AOA, indicating the likely presence of archaea without nitrification capacity in the surface. Gross nitrification rates declined significantly with depth and were positively correlated to AOB but negatively correlated to AOA gene abundances. We conclude that AOB are most likely responsible for regulating nitrification in these semi-arid soils. PMID:26053257

  17. Disturbance and temporal partitioning of the activated sludge metacommunity.

    PubMed

    Vuono, David C; Benecke, Jan; Henkel, Jochen; Navidi, William C; Cath, Tzahi Y; Munakata-Marr, Junko; Spear, John R; Drewes, Jörg E

    2015-02-01

    The resilience of microbial communities to press disturbances and whether ecosystem function is governed by microbial composition or by the environment have not been empirically tested. To address these issues, a whole-ecosystem manipulation was performed in a full-scale activated sludge wastewater treatment plant. The parameter solids retention time (SRT) was used to manipulate microbial composition, which started at 30 days, then decreased to 12 and 3 days, before operation was restored to starting conditions (30-day SRT). Activated sludge samples were collected throughout the 313-day time series in parallel with bioreactor performance ('ecosystem function'). Bacterial small subunit (SSU) rRNA genes were surveyed from sludge samples resulting in a sequence library of >417,000 SSU rRNA genes. A shift in community composition was observed for 12- and 3-day SRTs. The composition was altered such that r-strategists were enriched in the system during the 3-day SRT, whereas K-strategists were only present at SRTs⩾12 days. This shift corresponded to loss of ecosystem functions (nitrification, denitrification and biological phosphorus removal) for SRTs⩽12 days. Upon return to a 30-day SRT, complete recovery of the bioreactor performance was observed after 54 days despite an incomplete recovery of bacterial diversity. In addition, a different, yet phylogenetically related, community with fewer of its original rare members displaced the pre-disturbance community. Our results support the hypothesis that microbial ecosystems harbor functionally redundant phylotypes with regard to general ecosystem functions (carbon oxidation, nitrification, denitrification and phosphorus accumulation). However, the impacts of decreased rare phylotype membership on ecosystem stability and micropollutant removal remain unknown. PMID:25126758

  18. Disturbance and temporal partitioning of the activated sludge metacommunity

    PubMed Central

    Vuono, David C; Benecke, Jan; Henkel, Jochen; Navidi, William C; Cath, Tzahi Y; Munakata-Marr, Junko; Spear, John R; Drewes, Jörg E

    2015-01-01

    The resilience of microbial communities to press disturbances and whether ecosystem function is governed by microbial composition or by the environment have not been empirically tested. To address these issues, a whole-ecosystem manipulation was performed in a full-scale activated sludge wastewater treatment plant. The parameter solids retention time (SRT) was used to manipulate microbial composition, which started at 30 days, then decreased to 12 and 3 days, before operation was restored to starting conditions (30-day SRT). Activated sludge samples were collected throughout the 313-day time series in parallel with bioreactor performance (‘ecosystem function'). Bacterial small subunit (SSU) rRNA genes were surveyed from sludge samples resulting in a sequence library of >417 000 SSU rRNA genes. A shift in community composition was observed for 12- and 3-day SRTs. The composition was altered such that r-strategists were enriched in the system during the 3-day SRT, whereas K-strategists were only present at SRTs⩾12 days. This shift corresponded to loss of ecosystem functions (nitrification, denitrification and biological phosphorus removal) for SRTs⩽12 days. Upon return to a 30-day SRT, complete recovery of the bioreactor performance was observed after 54 days despite an incomplete recovery of bacterial diversity. In addition, a different, yet phylogenetically related, community with fewer of its original rare members displaced the pre-disturbance community. Our results support the hypothesis that microbial ecosystems harbor functionally redundant phylotypes with regard to general ecosystem functions (carbon oxidation, nitrification, denitrification and phosphorus accumulation). However, the impacts of decreased rare phylotype membership on ecosystem stability and micropollutant removal remain unknown. PMID:25126758

  19. Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, Part I: Semi-empirical model development.

    PubMed

    Sen, Dipankar; Randall, Clifford W

    2008-05-01

    Research was undertaken to develop a model for activated sludge, integrated fixed-film activated sludge (IFAS), and moving-bed biofilm reactor (MBBR) systems. The model can operate with up to 12 cells (reactors) in series, with biofilm media incorporated to one or more cells, except the anaerobic cells. The process configuration can be any combination of anaerobic, anoxic, aerobic, post-anoxic with or without supplemental carbon, and reaeration; it can also include any combination of step feed and recycles, including recycles for mixed liquor, return activated sludge, nitrates, and membrane bioreactors. This paper presents the structure of the model. The model embeds a biofilm model into a multicell activated sludge model. The biofilm flux rates for organics, nutrients, and biomass can be computed by two methods--a semi-empirical model of the biofilm that is relatively simpler, or a diffusional model that is computationally intensive. The values of the kinetic parameters for the model were measured using pilot-scale activated sludge, IFAS, and MBBR systems. For the semiempirical version, a series of Monod equations were developed for chemical oxygen demand, ammonium-nitrogen, and oxidized-nitrogen fluxes to the biofilm. Within the equations, a second Monod expression is used to simulate the effect of changes in biofilm thickness and fraction nitrifiers in the biofilm. The biofilm flux model is then linked to the activated sludge model. The diffusional model and the verification of the models are presented in subsequent papers (Sen and Randall, 2008a, 2008b). The model can be used to quantify the amount of media and surface area required to achieve nitrification, identify the best locations for the media, and optimize the dissolved oxygen levels and nitrate recycle rates. Some of the advanced features include the ability to apply different media types and fill fractions in cells; quantify nitrification, denitrification, and biomass production in the biofilm and

  20. Effects of oxygen concentration on the nitrifying activity of an aerobic hybrid granular sludge reactor.

    PubMed

    Filali, Ahlem; Bessiere, Yolaine; Sperandio, Mathieu

    2012-01-01

    The aim of the work was to quantify the influence of the simultaneous presence of flocs and granules in the nitrifying activity in a sequencing batch airlift reactor (SBAR). The nitrification rate and oxygen limitation of flocs, granules and hybrid sludge was investigated using respirometric assays at different dissolved oxygen concentrations. The spatial distribution of Ammonium Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB) was investigated using fluorescence in situ hybridization (FISH). Results showed that the nitrification rate was much less sensitive to oxygen limitation in systems containing a fraction of flocs than in pure granular sludge. Ammonium Oxidizing Bacteria (AOB) were found to be distributed in similar quantities in flocs and granules whereas the Nitrite Oxidizing Bacteria (NOB) were located preferentially in granules. This study showed that the presence of flocs with granules could increase the robustness of the process to transitory reductions of aeration. PMID:22233907

  1. Effect of arsenic on nitrification of simulated mining water.

    PubMed

    Papirio, S; Zou, G; Ylinen, A; Di Capua, F; Pirozzi, F; Puhakka, J A

    2014-07-01

    Mining and mineral processing of gold-bearing ores often release arsenic to the environment. Ammonium is released when N-based explosives or cyanide are used. Nitrification of simulated As-rich mining waters was investigated in batch bioassays using nitrifying cultures enriched in a fluidized-bed reactor (FBR). Nitrification was maintained at 100mg AsTOT/L. In batch assays, ammonium was totally oxidized by the FBR enrichment in 48 h. As(III) oxidation to As(V) occurred during the first 3h attenuating arsenic toxicity to nitrification. At 150 and 200mg AsTOT/L, nitrification was inhibited by 25%. Candidatus Nitrospira defluvii and other nitrifying species mainly colonized the FBR. In conclusion, the FBR enriched cultures of municipal activated sludge origins tolerated high As concentrations making nitrification a potent process for mining water treatment. PMID:24852647

  2. Evaluation of activated sludge for biodegradation of propylene glycol as an aircraft deicing fluid.

    PubMed

    Delorit, Justin D; Racz, LeeAnn

    2014-04-01

    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. PMID:24851333

  3. Denitrification kinetics in anoxic/aerobic activated sludge systems

    SciTech Connect

    Horne, G.M.

    1998-12-11

    Nitrogen removal needs at municipal wastewater treatment plants (WWTPs) have increased due to greater concerns about eutrophication and increased interest in reuse of treated municipal effluents. Biological processes are the most cost-effective method for nitrogen removal. Biological nitrogen removal is accomplished in two distinctly different processes by the conversion of nitrogen in the wastewater from organic nitrogen and ammonia to nitrate, followed by reduction of the nitrate to nitrogen gas. Nitrate production occurs in an aerobic activated sludge treatment zone during a process called nitrification. The nitrate is then converted through a series of intermediate steps to nitrogen gas in an anoxic zone (an anaerobic condition with nitrate present) during a process called denitrification, effectively removing the nitrogen from the wastewater. Many different WWTP designs have been developed to incorporate these two conditions for nitrogen removal.

  4. Co-conditioning and dewatering of alum sludge and waste activated sludge.

    PubMed

    Lai, J Y; Liu, J C

    2004-01-01

    Co-conditioning and dewatering behaviors of alum sludge and waste activated sludge were investigated. Two different sludges were mixed at various ratios (2:1; 1:1; 1:2; 1:4) for study. Capillary suction time (CST) and specific resistance to filtration (SRF) were utilized to assess sludge dewaterability. Relatively speaking, waste activated sludge, though of higher solid content, was more difficult to be dewatered than alum sludge. It was found that sludge dewaterability and settlability became better with increasing fraction of alum sludge in the mixed sludge. Dosage required of the cationic polyelectrolyte (KP-201C) for dewatering was reduced as well. It is proposed that alum sludge acts as skeleton builder in the mixed sludge, and renders the mixed sludge more incompressible which is beneficial for sludge dewatering. Implications of the results of the study to the sludge management plan for Taipei City that generates both alum sludge and waste activated sludge at significant amount are also discussed. The current sludge treatment and disposal plan in Metropolitan Taipei could be made more cost-effective. PMID:15580993

  5. Nitrification in brackish water recirculating aquaculture system integrated with activated packed bed bioreactor.

    PubMed

    Rejish Kumar, V J; Joseph, Valsamma; Philip, Rosamma; Bright Singh, I S

    2010-01-01

    Recirculation aquaculture systems (RAS) depend on nitrifying biofilters for the maintenance of water quality, increased biosecurity and environmental sustainability. To satisfy these requirements a packed bed bioreactor (PBBR) activated with indigenous nitrifying bacterial consortia has been developed and commercialized for operation under different salinities for instant nitrification in shrimp and prawn hatchery systems. In the present study the nitrification efficiency of the bioreactor was tested in a laboratory level recirculating aquaculture system for the rearing of Penaeus monodon for a period of two months under higher feeding rates and no water exchange. Rapid setting up of nitrification was observed during the operation, as the volumetric total ammonia nitrogen removal rates (VTR) increased with total ammonia nitrogen (TAN) production in the system. The average Volumetric TAN Removal Rates (VTR) at the feeding rate of 160 g/day from 54-60th days of culture was 0.1533+/-0.0045 kg TAN/m(3)/day. The regression between VTR and TAN explained 86% variability in VTR (P<0.001). The laboratory level RAS demonstrated here showed high performance both in terms of shrimp biomass yield and nitrification and environmental quality maintenance. Fluorescent in-situ Hybridization analysis of the reactor biofilm ensured the presence of autotrophic nitrifier groups such as Nitrosococcus mobilis lineage, Nitrobacter spp and phylum Nitrospira, the constituent members present in the original consortia used for activating the reactors. This showed the stability of the consortia on long term operation. PMID:20150717

  6. ACTIVELY CONTROLLED VORTEX DISPOSAL SYSTEM FOR SLUDGE WASTES

    EPA Science Inventory

    The development of an advanced sludge treatment concept is under way for applications to sludge wastes. The concept integrates primary treatment of sludge in an advanced vortex containment combustor (VCC) with subsequent post treatment in an actively controlled acoustic afterburn...

  7. ACTIVELY CONTROLLED VORTEX DISPOSAL SYSTEM FOR SLUDGE WASTES

    EPA Science Inventory

    The development of an advanced sludge treatment concept is underway for applications to sludge wastes. The concept integrates primary treatment of sludge in an advanced vortex containment combustor (VCC) with subsequent post treatment in an actively controlled acoustic afterburne...

  8. Screening wastewater for toxicity to activated sludge

    SciTech Connect

    Schneider, C.G.

    1987-01-01

    Several toxicity tests were compared to define their utility for prediction of toxicity to activated sludge. The tests included: (1) oxygen uptake rates in batch tests with activated sludge, (2) adenosine triphosphate (ATP) measurements in the same batch tests, (3) Warburg respirometer studies with activated sludge, and (4) a luminescent bacteria test (Microtox/sup TM/). An evaluation of the toxicity tests was made with several toxicants; nickel (II), mercury (II), 2,4-dichlorophenol (DCP) and 4,6-dinitro-o-cresol (DNOC). Because of differences in toxic mechanism, some of the toxicants produced greater toxic effects in some tests than in other tests. The ATP levels decreased significant when uncouplers of oxidative phosphorylation were studied (DCP and DNOC). Several procedures for measuring ATP were investigated and were found to be unsatisfactory when applied to activated sludge. A new method for extraction of ATP, which incorporated a sonic bath and trichloroacetic acid, was developed. The improved ATP method was used in the toxicity tests and for the additional studies. Current practice in environmental engineering relies on volatile suspended solids (VSS) as a measure of active biomass in activated sludge. After an improved ATP procedure was developed, ATP was investigated for estimation of active biomass. The fate of DCP in the toxicity tests was studied and an adsorptive mechanism was proposed that was based on membrane solubility. This mechanism explained the fate of DCP in the toxicity tests and is useful for understanding the fate of DCP in activated sludge.

  9. HYDRAULIC CHARACTERISTICS OF ACTIVATED SLUDGE SECONDARY CLARIFIERS

    EPA Science Inventory

    This study documented the hydraulic characteristics of typical activated sludge clarifiers. Modifications to the clarifier structures were made in an attempt to improve clarifier hydraulic characteristics and performance. Innovative fluorometric dye tracer studies were used to ob...

  10. Activated Sludge. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Boe, Owen K.; Klopping, Paul H.

    This student manual contains the textual material for a seven-lesson unit on activated sludge. Topic areas addressed in the lessons include: (1) activated sludge concepts and components (including aeration tanks, aeration systems, clarifiers, and sludge pumping systems); (2) activated sludge variations and modes; (3) biological nature of activated…

  11. Activated Sludge and other Aerobic Suspended Culture Processes.

    PubMed

    Li, Chunying; Wei, Li; Chang, Chein-Chi; Zhang, Yuhua; Wei, Dong

    2016-10-01

    This is a literature review for the year 2015 and contains information specifically associated with suspended growth processes including activated sludge, upflow anaerobic sludge blanket, and sequencing batch reactors. The review encompasses modeling and kinetics, nutrient removal, system design and operation. Compared to past reviews, many topics show increase in activity in 2015. These include, fate and effect of xenobiotics, industrial wastes treatment with sludge, and pretreatment for the activated sludge. These topics are referred to the degradation of constituents in activated sludge. Other sections include population dynamics, process microbiology give an insight into the activated sludge. The subsection in industrial wastes: converting sewage sludge into biogases was also mentioned. PMID:27620082

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

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

    PubMed Central

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

    2015-01-01

    Oxic-settling-anaerobic process (OSA) was known as a cost-effective way to reduce the excess sludge production with simple upgrade of conventional activated sludge process (CAS). A low oxidation-reduction potential (ORP) level was the key factor to sludge decay and lysis in the sludge holding tank of the OSA process. However, the ORP control with nitrogen purge or chemical dosing in the OSA process would induce extra expense and complicate the operation. Hence, in this study, a sludge holding tank using gravity thickening was applied to OSA process to reduce the excess sludge production without any ORP control. Results showed that the modified OSA process not only reduced the excess sludge production effectively but also improved the sludge settleability without affected the treatment capacity. The reduction of the excess sludge production in the modified OSA process resulted from interactions among lots of factors. The key element of the process was the gravity thickening sludge holding tank. PMID:26350761

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

    PubMed

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

    2001-08-01

    The impact of temperature on nitrification in biological granular activated carbon (GAC) filters was evaluated in order to improve the understanding of the nitrification process in drinking water treatment. The study was conducted in a northern climate where very cold water temperatures (below 2 degrees C) prevail for extended periods and rapid shifts of temperature are frequent in the spring and fall. Ammonia removals were monitored and the fixed nitrifying biomass was measured using a method of potential nitrifying activity. The impact of temperature was evaluated on two different filter media: an opened superstructure wood-based activated carbon and a closed superstructure activated carbon-based on bituminous coal. The study was conducted at two levels: pilot scale (first-stage filters) and full-scale (second-stage filters) and the results indicate a strong temperature impact on nitrification activity. Ammonia removal capacities ranged from 40 to 90% in pilot filters, at temperatures above 10 degrees C, while more than 90% ammonia was removed in the full-scale filters for the same temperature range. At moderate temperatures (4-10 degrees C), the first stage pilot filters removed 10-40% of incoming ammonia for both media (opened and closed superstructure). In the full-scale filters, a difference between the two media in nitrification performances was observed at moderate temperatures: the ammonia removal rate in the opened superstructure support (more than 90%) was higher than in the closed superstructure support (45%). At low temperatures (below 4 degrees C) both media performed poorly. Ammonia removal capacities were below 30% in both pilot- and full-scale filters. PMID:11471692

  15. Effects of drying on nitrification activity in zeoponic medium used for long-term space missions

    NASA Technical Reports Server (NTRS)

    McGilloway, R. L.; Weaver, R. W.

    2004-01-01

    One component of a proposed life support system is the use of zeoponic substrates, which slowly release NH4+ into "soil" solution, for the production of plants. Nitrifying bacteria that convert NH4+ to NO3- are among the important microbial components of these systems. Survival of nitrifying bacteria in dry zeoponic substrates is needed, because the substrate would likely be stored in an air-dry state between croppings. Substrate was enriched for nitrifying bacteria and allowed to air-dry in a laminar flow hood. Stored substrate was analyzed for nitrifier survivability by measuring nitrifier activity at the beginning, 3 days, 1, 2, and 3 weeks. After rewetting, activity was approximately 9 micrograms N g-1 h-1 regardless of storage time. Nitrification rates did not decrease during storage. It seems unlikely that drying between plantings would result in practical reductions in nitrification, and reinoculation with nitrifying bacteria would not be necessary.

  16. Measurement of glutathione in activated sludges.

    PubMed

    Dziurla, M A; Leroy, P; Strünkmann, G W; Salhi, M; Lee, D U; Camacho, P; Heinz, V; Müller, J A; Paul, E; Ginestet, Ph; Audic, J M; Block, J C

    2004-01-01

    Thermal, electric, mechanical or oxidative stress seem a promising way to reduce the production of excess activated sludge during biological wastewater treatment. However, the adaptation and the resistance of the sludge microbial ecosystem to stress conditions is a major question as it may definitively limit the effect of some treatments. Defence mechanisms developed by aerobic organisms, in particular, in response to oxidative stress involve various antioxidant activities and compounds such as glutathione. An HPLC method was developed for measuring reduced and total glutathione (GSH and GSHt) in perchloric acid sludge extracts. The method was sensitive, highly specific and validated for linearity, precision and recovery. Considering the extraction yield and the oxidation of GSH during extract storage, the measured GSH concentration was estimated to represent 60% of the GSH content from activated sludges. GSHt ranged from 0.32 to 3.34micromolg(-1) volatile solids and the GSH/GSHt ratio ranged from 32% to 91%. Measurements performed on sludges stressed in precise conditions selected to reach a reduction of sludge production showed a decrease of GSH and GSHt concentrations with thermal, mechanical, electric and ozone stress. PMID:14630122

  17. Complete solids retention activated sludge process.

    PubMed

    Amanatidou, E; Samiotis, G; Trikoilidou, E; Pekridis, G; Tsikritzis, L

    2016-01-01

    In a slaughterhouse's full-scale extended aeration activated sludge wastewater treatment plant (WWTP), operating under complete solids retention time, the evolution of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentration, food to micro-organisms ratio (F/M) and substrate utilization rate (SUR) were studied for over a year. Biomass growth phases in correlation to sludge biological and morphological characteristics were studied. Three distinguished growth phases were observed during the 425 days of monitoring. The imposed operational conditions led the process to extended biomass starvation conditions, minimum F/M, minimum SUR and predator species growth. MLSS and MLVSS reached a stabilization phase (plateau phase) where almost zero sludge accumulation was observed. The concept of degradation of the considered non-biodegradable particulate compounds in influent and in biomass (cell debris) was also studied. Comparison of evolution of observed sludge yields (Yobs) in the WWTP with Yobs predictions by activated sludge models verified the degradation concept for the considered non-biodegradable compounds. Control of the sedimentation process was achieved, by predicting the solids loading rate critical point using state point analysis and stirred/unstirred settling velocity tests and by applying a high return activated sludge rate. The nitrogen gas related sedimentation problems were taken into consideration. PMID:27003077

  18. [Effect of osmotic pressure on nitrification].

    PubMed

    Zheng, Ping; Wu, Ming-Sheng

    2006-01-01

    The effect of osmotic pressure on nitrification was investigated in the internal-loop air-lift nitrifying reactor. When influent ammonia concentration is kept at 420mg x L(-1) and influent osmotic pressure is increased from 4.3 to 18.8 x 10(5) Pa, the ammonia conversion of the nitrifying bioreactor is maintained between 93% and 100%. After influent osmotic pressure is further increased to 19.2 x 10(5)Pa, the ammonia conversion goes down to 69.2%. The influence of osmotic pressure on nitrification takes place without any alarm and the critical osmotic pressure is between 18.8 x 10(5) and 19.2 x 10(5) Pa. During osmotic stress, the nitrifying bacterial populations in the activated sludge become simplified, the cell size becomes smaller, the inner membrane becomes less and some unknown inclusion particles are formed. The cell structure is restored as soon as the osmotic pressure is removed. Addition of potassium is able to relieve the effect of osmotic pressure on nitrification. The nitrifying activity of the activated sludge is stimulated by the osmotic stress, and the specific ammonia conversion is increased from 0.083 kg x kg(-1) x d(-1) to 0.509 kg x kg(-1) x d(-1) and 2.569 kg x kg(-1) x d(-1), respectively. PMID:16572857

  19. Effects of SRT and DO on N2O reductase activity in an anoxic-oxic activated sludge system.

    PubMed

    Noda, N; Kaneko, N; Mikami, M; Kimochi, Y; Tsuneda, S; Hirata, A; Mizuochi, M; Inamori, Y

    2003-01-01

    Nitrous oxide (N2O) is emitted from wastewater treatment processes, and is known to be a green house gas contributing to global warming. It is thus important to develop technology that can suppress N2O emission. The effects of sludge retention time (SRT) and dissolved oxygen (DO) on N2O emission in an anoxic-oxic activated sludge system were estimated. Moreover, the microbial community structure in the sludge, which plays an important role in N2O suppression, was clarified based on nitrous oxide reductase (nosZ) gene analysis by molecular biological techniques. The results showed that under low SRT conditions, nitrification efficiency was reduced and the N2O emission rate in the oxic reactors was increased. It was also observed that N2O emission was enhanced under low DO conditions, where the available oxygen is insufficient for nitrification. Moreover, molecular analysis revealed that the clones identified in this study were closely related to Ralstonia eutropha and Paracoccus denitrificans. The fact that the identified sequences are not closely related to known culturable denitrifier nosZ sequences indicates a substantial in situ diversity of denitrifiers contributing to N2O suppression, which are not reflected in the cultivatable fraction of the population. The further application of these new molecular techniques should serve to enhance our knowledge of the microbial community of denitrifying bacteria contributing to N2O suppression in wastewater treatment systems. PMID:14753557

  20. Enhancement of polyether biodegradation in activated sludge

    SciTech Connect

    Christopher, L.J.

    1993-01-01

    Previous studies in this laboratory showed that pretreatment with Petroleum Chemical Extinguisher[reg sign] (PCE), a C[sub 18] unsaturated fatty acid diester of polyethylene glycol (PEG), enhanced the biodegradation of PEG 1,000 and PEG 1,450 in soil. In this study the ability of PCE and other PEG-fatty acid diesters to enhance biodegradation of PEGs in activated sludge was investigated. Additionally, polyether-fatty acid esters similar to PCE were synthesized and tested to determine how they affected biodegradation of PEGs and other polyethers. Attempts were made to understand the mechanism for enhancement of biodegradation. Carbon-dioxide evolution and thin-layer chromatographic analysis indicated degradation of PEG 1,000, PEG 1,450, and PEG 3,350 in sludge samples which were previously exposed to PCE. Those samples which were not pre-treated with PCE showed no detectable PEG degradation during the two-week study. Preexposure to PCE did not enhance subsequent degradation of PEG 8,000, nor polypropylene glycol (PPG) 1,025. However, pretreatment of sludge with a PPG 1,025-di oleic acid ester promoted PPG 1,205 degradation. Interestingly, microbial populations do not seem to be gaining much biomass or energy from the degradation of PEG-di fatty acid esters or PEGs. When PCE-pretreated sludge samples were given [sup 14]C-PEG 3,350 as substrate, evolution of [sup 14]CO[sub 2] occurred and little (<5%) of the [sup 14]C was assimilated by the microorganisms in the sludge. Futhermore, determinations of ATP content and esterase activity of sludge samples suggested that there was not a substantial increase in biomass as a result of degradation of either PCE or PEGs. PCE preexposure effected an increase in PEG dehydrogenase activity. This increase may be due to induction of enzymes responsible for PEG biodegradation or selection for organisms in the microbial population which are PEG degraders.

  1. DOWNFLOW GRANULAR FILTRATION OF ACTIVATED SLUDGE EFFLUENTS

    EPA Science Inventory

    The performance of downflow granular filters subjected to effluents from activated sludge processes was investigated at the EPA-DC Pilot Plant in Washington, D.C. Several media combinations were investigated, including both single anthracite and dual anthracite-sand configuration...

  2. DENSITY CURRENTS IN ACTIVATED SLUDGE SECONDARY CLARIFIERS

    EPA Science Inventory

    Density currents form in activated sludge secondary clarifiers because the mixed liquor has a density greater than the treated wastewater in the clarifier. This causes the mixed liquor to plunge to the bottom of the clarifier establishing relatively high velocity currents within ...

  3. METALS DISTRIBUTIONS IN ACTIVATED SLUDGE SYSTEMS

    EPA Science Inventory

    This project developed models to predict the distribution of metals in activated sludge system process streams. The data used to develop the models were obtained through extended pilot studies from a previous project. The objectives of the study were to evaluate the effects of wa...

  4. Biodegradability of activated sludge organics under anaerobic conditions.

    PubMed

    Ekama, G A; Sötemann, S W; Wentzel, M C

    2007-01-01

    From an experimental and theoretical investigation of the continuity of activated sludge organic (COD) compounds along the link between the fully aerobic or N removal activated sludge and anaerobic digestion unit operations, it was found that the unbiodegradable particulate organics (i) originating from the influent wastewater and (ii) generated by the activated sludge endogenous process, as determined from response of the activated sludge system, are also unbiodegradable under anaerobic digestion conditions. This means that the activated sludge biodegradable organics that can be anaerobically digested can be calculated from the active fraction of the waste activated sludge based on the widely accepted ordinary heterotrophic organism (OHO) endogenous respiration/death regeneration rates and unbiodegradable fraction. This research shows that the mass balances based steady state and dynamic simulation activated sludge, aerobic digestion and anaerobic digestion models provide internally consistent and externally compatible elements that can be coupled to produce plant wide steady state and dynamic simulation WWTP models. PMID:17045327

  5. Fate of alkylphenolic compounds during activated sludge treatment: impact of loading and organic composition.

    PubMed

    McAdam, Ewan J; Bagnall, John P; Soares, Ana; Koh, Yoong K K; Chiu, Tze Y; Scrimshaw, Mark D; Lester, John N; Cartmell, Elise

    2011-01-01

    The impact of loading and organic composition on the fate of alkylphenolic compounds in the activated sludge plant (ASP) has been studied. Three ASP designs comprising carbonaceous, carbonaceous/nitrification, and carbonaceous/nitrification/denitrification treatment were examined to demonstrate the impact of increasing levels of process complexity and to incorporate a spectrum of loading conditions. Based on mass balance, overall biodegradation efficiencies for nonylphenol ethoxylates (NPEOs), short chain carboxylates (NP(1-3)EC) and nonylphenol (NP) were 37%, 59%, and 27% for the carbonaceous, carbonaceous/nitrification, and carbonaceous/nitrification/denitrification ASP, respectively. The presence of a rich community of ammonia oxidizing bacteria does not necessarily facilitate effective alkylphenolic compound degradation. However, a clear correlation between alkylphenolic compound loading and long chain ethoxylate compound biodegradation was determined at the three ASPs, indicating that at higher initial alkylphenolic compound concentrations (or load), greater ethoxylate biotransformation can occur. In addition, the impact of settled sewage organic composition on alkylphenolic compound removal was evaluated. A correlation between the ratio of chemical oxygen demand (COD) to alkylphenolic compound concentration and biomass activity was determined, demonstrating the inhibiting effect of bulk organic matter on alkylphenol polyethoxylate transformation activity. At all three ASPs the biodegradation pathway proposed involves the preferential biodegradation of the amphiphilic ethoxylated compounds, after which the preferential attack of the lipophilic akylphenol moiety occurs. The extent of ethoxylate biodegradation is driven by the initial alkylphenolic compound concentration and the proportion of COD constituted by the alkylphenol polyethoxylates (APEOs) and their metabolites relative to the bulk organic concentration of the sewage composed of proteins, acids, fats

  6. Activated packed bed bioreactor for rapid nitrification in brackish water hatchery systems.

    PubMed

    Kumar, V J Rejish; Achuthan, Cini; Manju, N J; Philip, Rosamma; Singh, I S Bright

    2009-03-01

    A packed bed bioreactor (PBBR) was developed for rapid establishment of nitrification in brackish water hatchery systems in the tropics. The reactors were activated by immobilizing ammonia-oxidizing (AMONPCU-1) and nitrite-oxidizing (NIONPCU-1) bacterial consortia on polystyrene and low-density polyethylene beads, respectively. Fluorescence in situ hybridization demonstrated the presence of autotrophic nitrifiers belong to Nitrosococcus mobilis, lineage of beta ammonia oxidizers and nitrite oxidizer Nitrobacter sp. in the consortia. The activated reactors upon integration to the hatchery system resulted in significant ammonia removal (P < 0.01) culminating to its undetectable levels. Consequently, a significantly higher percent survival of larvae was observed in the larval production systems. With spent water the reactors could establish nitrification with high percentage removal of ammonia (78%), nitrite (79%) and BOD (56%) within 7 days of initiation of the process. PBBR is configured in such a way to minimize the energy requirements for continuous operation by limiting the energy inputs to a single stage pumping of water and aeration to the aeration cells. The PBBR shall enable hatchery systems to operate under closed recirculating mode and pave the way for better water management in the aquaculture industry. PMID:19039611

  7. Activated Sludge and other Aerobic Suspended Culture Processes.

    PubMed

    Wei, Li; Wei, Chao; Chang, Chein-Chi; You, Shao-Hong

    2015-10-01

    This is a literature review for the year 2014 and contains information specifically associated with suspended growth processes including activated sludge and sequencing batch reactors. This review is a subsection of the treatment systems section of the annual literature review. The review encompasses modeling and kinetics, nutrient removal, system design and operation. Compared to past reviews, many topics show increase in activity in 2014. These include, nitrogen and phosphorus control, fate and effect of xenobiotics, industrial wastes treatment, and some new method for the determination of activated sludge. These topics are referred to the degradation of constituents in activated sludge. Other sections include population dynamics, process microbiology of activated sludge, modeling and kinetics. Many of the subsections in the industrial wastes: converting sewage sludge into fuel gases, thermos-alkali hydrolysis of Waste Activated Sludge (WAS), sludge used as H2 S adsorbents were also mentioned in this review. PMID:26420077

  8. Degradation of corticosteroids during activated sludge processing.

    PubMed

    Miyamoto, Aoi; Kitaichi, Yuko; Uchikura, Kazuo

    2014-01-01

    Laboratory tests of the decomposition of corticosteroids during activated sludge processing were investigated. Corticosteroid standards were added to activated sludge, and aliquots were regularly taken for analysis. The corticosteroids were extracted from the samples using a solid-phase extraction method and analyzed LC-MS. Ten types of corticosteroids were measured and roughly classified into three groups: 1) prednisolone, triamcinolone, betamethasone, prednisolone acetate, and hydrocortisone acetate, which decomposed within 4 h; 2) flunisolide, betamethasone valerate, and budesonide of which more than 50% remained after 4 h, but almost all of which decomposed within 24 h; and 3) triamcinolone acetonide, and fluocinolone acetonide of which more than 50% remained after 24 h. The decomposed ratio was correlated with each corticosteroid's Log P, especially groups 2) and 3). PMID:24390495

  9. Activated sludge degradation of adipic acid esters.

    PubMed Central

    Saeger, V W; Kalley, R G; Hicks, O; Tucker, E S; Mieure, J P

    1976-01-01

    The biodegradability of three aliphatic adipic acid diesters and a 1,3-butylene glycol adipic acid polyester was determined in acclimated, activated sludge systems. Rapid primary biodegradation from 67 to 99+% was observed at 3- and 13-mg/liter feed levels for di-n-hexyl adipate, di(2-ethylhexyl) adipate, and di(heptyl, nonyl) adipate in 24 h. When acclimated, activated sludge microorganisms were employed as the seed for two carbon dioxide evolution procedures, greater than 75% of the theoretical carbon dioxide was evolved for the three diesters and the polyester in a 35-day test period. The essentially complete biodegradation observed in these studies suggests that these esters would not persist when exposed to similar mixed microbial populations in the environment. PMID:1275494

  10. Preparation of ferric-activated sludge-based adsorbent from biological sludge for tetracycline removal.

    PubMed

    Yang, Xin; Xu, Guoren; Yu, Huarong; Zhang, Zhao

    2016-07-01

    Ferric activation was novelly used to produce sludge-based adsorbent (SBA) from biological sludge through pyrolysis, and the adsorbents were applied to remove tetracycline from aqueous solution. The pyrolysis temperature and mass ratio (activator/dried sludge) greatly influenced the surface area and pore characteristics of SBA. Ferric activation could promote the porous structure development of adsorbents, and the optimum preparation conditions were pyrolysis temperature 750°C and mass ratio (activator/dried sludge) 0.5. In batch experiments, ferric-activated SBA showed a higher adsorption capacity for tetracycline than non-activated SBA, because the enhanced mesoporous structure favored the diffusion of tetracycline into the pores, the iron oxides and oxygen-containing functional groups in the adsorbents captured tetracycline by surface complexation. The results indicate that ferric activation is an effective approach for preparing adsorbents from biological sludge to remove tetracycline, providing a potential option for waste resource recovery. PMID:27038265

  11. Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, part III: analysis and verification.

    PubMed

    Sen, Dipankar; Randall, Clifford W

    2008-07-01

    Research was undertaken to analyze and verify a model that can be applied to activated sludge, integrated fixed-film activated sludge (IFAS), and moving-bed biofilm reactor (MBBR) systems. The model embeds a biofilm model into a multicell activated sludge model. The advantage of such a model is that it eliminates the need to run separate computations for a plant being retrofitted from activated sludge to IFAS or MBBR. The biofilm flux rates for organics, nutrients, and biomass can be computed by two methods-a semi-empirical model of the biofilm that is relatively simpler, or a diffusional model of the biofilm that is computationally intensive. Biofilm support media can be incorporated to the anoxic and aerobic cells, but not the anaerobic cells. The model can be run for steady-state and dynamic simulations. The model was able to predict the changes in nitrification and denitrification at both pilot- and full-scale facilities. The semi-empirical and diffusional models of the biofilm were both used to evaluate the biofilm flux rates for media at different locations. The biofilm diffusional model was used to compute the biofilm thickness and growth, substrate concentrations, volatile suspended solids (VSS) concentration, and fraction of nitrifiers in each layer inside the biofilm. Following calibration, both models provided similar effluent results for reactor mixed liquor VSS and mixed liquor suspended solids and for the effluent organics, nitrogen forms, and phosphorus concentrations. While the semi-empirical model was quicker to run, the diffusional model provided additional information on biofilm thickness, quantity of growth in the biofilm, and substrate profiles inside the biofilm. PMID:18710147

  12. High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation.

    PubMed

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

    2016-10-01

    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. PMID:27453288

  13. Role of Nocardia in Activated Sludge

    PubMed Central

    Bafghi, Mehdi Fatahi; Yousefi, Nader

    2016-01-01

    Activated sludge process is a biological process that is widely used in the domestic and industrial wastewater treatment in over the world. The foam formation is often reported in wastewater treatment plants which are related to this process. Some operational problems can be created by foaming, such as effluent quality deteriorates, the creation of malodorous, increased time requirements in order to plant maintenance, and in extreme cases, hazardous working conditions resulting from foam spilling out of the aeration basin and as well as increased in operational costs. There are different ways to overcome this problem, such as reduce air flows into the aeration basin, reduction in the grease and oil content of the wastewater, surface and return activated sludge (RAS) chlorination, anoxic and anaerobic selectors, solid retention time (SRT) control and antifoams and organic polymer addition. On the other hand, rapid and accurate identification of the foam causes is in the first step to control bulking and foaming. Foam problem is often created by filamentous bacteria, such as Nocardia and Gordonia species. This bacterium has a role important in activated sludge. PMID:27418874

  14. Role of Nocardia in Activated Sludge.

    PubMed

    Bafghi, Mehdi Fatahi; Yousefi, Nader

    2016-05-01

    Activated sludge process is a biological process that is widely used in the domestic and industrial wastewater treatment in over the world. The foam formation is often reported in wastewater treatment plants which are related to this process. Some operational problems can be created by foaming, such as effluent quality deteriorates, the creation of malodorous, increased time requirements in order to plant maintenance, and in extreme cases, hazardous working conditions resulting from foam spilling out of the aeration basin and as well as increased in operational costs. There are different ways to overcome this problem, such as reduce air flows into the aeration basin, reduction in the grease and oil content of the wastewater, surface and return activated sludge (RAS) chlorination, anoxic and anaerobic selectors, solid retention time (SRT) control and antifoams and organic polymer addition. On the other hand, rapid and accurate identification of the foam causes is in the first step to control bulking and foaming. Foam problem is often created by filamentous bacteria, such as Nocardia and Gordonia species. This bacterium has a role important in activated sludge. PMID:27418874

  15. Updated activated sludge model number 1 parameter values for improved prediction of nitrogen removal in activated sludge processes: validation at 13 full-scale plants.

    PubMed

    Choubert, Jean-Marc; Stricker, Anne-Emmanuelle; Marquot, Aurélien; Racault, Yvan; Gillot, Sylvie; Héduit, Alain

    2009-01-01

    The Activated Sludge Model number 1 (ASM1) is the main model used in simulation projects focusing on nitrogen removal. Recent laboratory-scale studies have found that the default values given 20 years ago for the decay rate of nitrifiers and for the heterotrophic biomass yield in anoxic conditions were inadequate. To verify the relevance of the revised parameter values at full scale, a series of simulations were carried out with ASM1 using the original and updated set of parameters at 20 degrees C and 10 degrees C. The simulation results were compared with data collected at 13 full-scale nitrifying-denitrifying municipal treatment plants. This work shows that simulations using the original ASM1 default parameters tend to overpredict the nitrification rate and underpredict the denitrification rate. The updated set of parameters allows more realistic predictions over a wide range of operating conditions. PMID:19860142

  16. Evaluating sedimentation problems in activated sludge treatment plants operating at complete sludge retention time.

    PubMed

    Amanatidou, Elisavet; Samiotis, Georgios; Trikoilidou, Eleni; Pekridis, George; Taousanidis, Nikolaos

    2015-02-01

    Zero net sludge growth can be achieved by complete retention of solids in activated sludge wastewater treatment, especially in high strength and biodegradable wastewaters. When increasing the solids retention time, MLSS and MLVSS concentrations reach a plateau phase and observed growth yields values tend to zero (Yobs ≈ 0). In this work, in order to evaluate sedimentation problems arised due to high MLSS concentrations and complete sludge retention operational conditions, two identical innovative slaughterhouse wastewater treatment plants were studied. Measurements of wastewaters' quality characteristics, treatment plant's operational conditions, sludge microscopic analysis and state point analysis were conducted. Results have shown that low COD/Nitrogen ratios increase sludge bulking and flotation phenomena due to accidental denitrification in clarifiers. High return activated sludge rate is essential in complete retention systems as it reduces sludge condensation and hydraulic retention time in the clarifiers. Under certain operational conditions sludge loading rates can greatly exceed literature limit values. The presented methodology is a useful tool for estimation of sedimentation problems encountered in activated sludge wastewater treatment plants with complete retention time. PMID:25463928

  17. Biofilms Versus Activated Sludge: Considerations in Metal and Metal Oxide Nanoparticle Removal from Wastewater.

    PubMed

    Walden, Connie; Zhang, Wen

    2016-08-16

    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. PMID:27437755

  18. Neem (Azadirachta indica) seed kernel powder retards urease and nitrification activities in different soils at contrasting moisture and temperature regimes.

    PubMed

    Mohanty, Sangita; Patra, Ashok K; Chhonkar, Pramod K

    2008-03-01

    A laboratory experiment was conducted to examine the potentiality of a natural resource neem (Azadirachta indica) seed kernel powder (NSKP) to reduce the urease and nitrification activities in different soils (viz., normal, acid, and sodic) at contrasting moisture (1:1 soil to water and field capacity) and temperature regimes (10 degrees C and 37 degrees C). Results have revealed that application of NSKP with urea did not exhibit any urease inhibitory property in normal and sodic soils, but in acid soil it had maintained higher concentration of urea than the urea alone treated samples for two weeks after application. At 37 degrees C and under field capacity moisture level, urea hydrolysis was more rapid than at 10 degrees C and under waterlogged (1:1) conditions. The NSKP has showed variable effects (4-28%) to inhibit nitrification during 7-21 days after application, depending upon the soil types, temperature and moisture regimes. The nitrification activity was significantly low in acid soil followed by normal and sodic soils. The present study suggests that NSKP has the potential to retard the urease activity in acid soil, and nitrification in all the soils, and thus it may be used along with urea for the better use of applied -N. PMID:17360179

  19. Purifying capability, enzyme activity, and nitrification potentials in December in integrated vertical flow constructed wetland with earthworms and different substrates.

    PubMed

    Xu, Defu; Gu, Jiaru; Li, Yingxue; Zhang, Yu; Howard, Alan; Guan, Yidong; Li, Jiuhai; Xu, Hui

    2016-01-01

    The response of purifying capability, enzyme activity, nitrification potentials, and total number of bacteria in the rhizosphere in December to wetland plants, substrates, and earthworms was investigated in integrated vertical flow constructed wetlands (IVFCW). The removal efficiency of total nitrogen (TN), NH4-N, chemical oxygen demand (COD), and total phosphorus (TP) was increased when earthworms were added into IVFCW. A significantly average removal efficiency of N in IVFCW that employed river sand as substrate and in IVFCW that employed a mixture of river sand and Qing sand as substrate was not found. However, the average removal efficiency of P was higher in IVFCW with a mixture of river sand and Qing sand as substrate than in IVFCW with river sand as substrate. Invertase activity in December was higher in IVFCW that used a mixture of river sand and Qing sand as substrate than in IVFCW which used only river sand as substrate. However, urease activity, nitrification potential, and total number of bacteria in December was higher in IVFCW that employed river sand as substrate than in IVFCW with a mixture of river sand and Qing sand as substrate. The addition of earthworms into the integrated vertical flow constructed wetland increased the above-ground biomass, enzyme activity (catalase, urease, and invertase), nitrification potentials, and total number of bacteria in December. The above-ground biomass of wetland plants was significantly positively correlated with urease and nitrification potentials (p < 0.01). The addition of earthworms into IVFCW increased enzyme activity and nitrification potentials in December, which resulted in improving purifying capability. PMID:26573309

  20. Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions.

    PubMed

    Fernandez-Fontaina, E; Gomes, I B; Aga, D S; Omil, F; Lema, J M; Carballa, M

    2016-01-15

    The effect of nitrification, nitratation and heterotrophic conditions on the biotransformation of several pharmaceuticals in a highly enriched nitrifying activated sludge was evaluated in this study by selective activation of ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and heterotrophic bacteria. Nitrifiers displayed a noticeable capacity to process ibuprofen due to hydroxylation by ammonia monooxygenase (AMO) to produce 2-hydroxy-ibuprofen. Naproxen was also biotransformed under nitrifying conditions. On the other hand, heterotrophic bacteria present in the nitrifying activated sludge (NAS) biotransformed sulfamethoxazole. In contrast, both nitrifying and heterotrophic activities were ineffective against diclofenac, diazepam, carbamazepine and trimethoprim. Similar biotransformation rates of erythromycin, roxithromycin and fluoxetine were observed under all conditions tested. Overall, results from this study give more evidence on the role of the different microbial communities present in activated sludge reactors on the biological removal of pharmaceuticals. PMID:26479917

  1. Nitrogen Removal in a Full-Scale Domestic Wastewater Treatment Plant with Activated Sludge and Trickling Filter

    PubMed Central

    Nourmohammadi, Davood; Esmaeeli, Mir-Bager; Akbarian, Hossein; Ghasemian, Mohammad

    2013-01-01

    During the last decade, more stringent effluent requirements concerning the nutrients effluent values have been imposed by legislation and social concern. In this study, efficiency of total nitrogen removal in activated sludge and trickling filter processes (AS/TF) was investigated in Tehran North wastewater treatment plant. Biological system in this site was included, anoxic selector tank, aeration tank, final sedimentation, and trickling filter. A part of treated wastewater before chlorination was mixed with supernatant of dewatered sludge and fed to the trickling filter. Supernatant of dewatered sludge with high concentration of NH4-N was diluted by treated wastewater to provide complete nitrification in trickling filter Produced nitrate in trickling filter was arrived to the anoxic tank and converted to nitrogen gas by denitrification. According to the study result, low concentration of organic carbone and high concentration of NH4-N led to nitrification in TF, then nitrate denitrification to nitrogen gas occurred in selector area. NH4-N concentration decreased from 26.8 mg/L to 0.29 mg/L in TF, and NO3-N concentration increased from 8.8 mg/L to 27 mg/L in TF. Consequently, the total nitrogen decreased approximately to 50% in biological process. This efficiency has been observed in returned flow around 24% from final sedimentation into TF. It was concluded that, in comparison with biological nutrient removal processes, this process is very efficient and simple. PMID:23710197

  2. Nitrogen removal in a full-scale domestic wastewater treatment plant with activated sludge and trickling filter.

    PubMed

    Nourmohammadi, Davood; Esmaeeli, Mir-Bager; Akbarian, Hossein; Ghasemian, Mohammad

    2013-01-01

    During the last decade, more stringent effluent requirements concerning the nutrients effluent values have been imposed by legislation and social concern. In this study, efficiency of total nitrogen removal in activated sludge and trickling filter processes (AS/TF) was investigated in Tehran North wastewater treatment plant. Biological system in this site was included, anoxic selector tank, aeration tank, final sedimentation, and trickling filter. A part of treated wastewater before chlorination was mixed with supernatant of dewatered sludge and fed to the trickling filter. Supernatant of dewatered sludge with high concentration of NH4-N was diluted by treated wastewater to provide complete nitrification in trickling filter Produced nitrate in trickling filter was arrived to the anoxic tank and converted to nitrogen gas by denitrification. According to the study result, low concentration of organic carbone and high concentration of NH4-N led to nitrification in TF, then nitrate denitrification to nitrogen gas occurred in selector area. NH4-N concentration decreased from 26.8 mg/L to 0.29 mg/L in TF, and NO3-N concentration increased from 8.8 mg/L to 27 mg/L in TF. Consequently, the total nitrogen decreased approximately to 50% in biological process. This efficiency has been observed in returned flow around 24% from final sedimentation into TF. It was concluded that, in comparison with biological nutrient removal processes, this process is very efficient and simple. PMID:23710197

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

    PubMed

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

    2014-08-01

    The performance of a new pilot-scale six tanks activated sludge process has been evaluated for 303 d, receiving real domestic wastewater with a flow rate of 15-24.4 L/h. Partial nitrification via nitrite and microbial community structure were investigated in this system. The result shows that the nitrite accumulation rate was achieved successfully over 94% in the last aerobic compartment through a combination of short hydraulic retention time and low dissolved oxygen (DO) level. Fluorescence in situ hybridization analysis was used to correlate ammonia-oxidizing bacteria (AOB) numbers with nutrient removal via nitrite. It was shown that in response to complete and partial nitrification modes, the numbers of AOB population were 7.7 x 10(7) cells/g mixed liquor suspended solids (MLSS) and 5.31 x 10(8) cells/g MLSS, respectively. The morphology of the sludge indicated that there is a small rod-shaped and spherical cluster which was mainly dominantly bacterial according to scanning electron microscope. Higher pollutant removal efficiencies of 86.2%, 98%, and 96.1%, for total nitrogen, NH4+ - N, and total phosphorus, respectively, were achieved by a long-term operation of the six tanks activated sludge process at a low DO concentration and low chemical oxygen demand to nitrogen ratio which were approximately equal to the complete nitrification-ldenitrification with the addition of an external carbon source at a concentration of 1.5-2.5 mg/L. PMID:24956781

  4. Relating the Diversity, Abundance, and Activity of Ammonia-Oxidizing Archaeal Communities to Nitrification Rates in the Coastal Ocean

    NASA Astrophysics Data System (ADS)

    Tolar, B. B.; Smith, J. M.; Chavez, F.; Francis, C.

    2015-12-01

    Ammonia oxidation, the rate-limiting first step of nitrification, is an important link between reduced (ammonia) and oxidized (nitrate) nitrogen, and controls the relative distribution of these forms of inorganic nitrogen. This process is catalyzed via the ammonia monooxygenase enzyme of both ammonia-oxidizing Bacteria (AOB) and Archaea (AOA); the α subunit of this enzyme is encoded by the amoA gene and has been used as the molecular marker to detect this process. In the ocean, AOA are typically 10-1000 times more and are likely more active than AOB, and thus are key players in the marine nitrogen cycle. Monterey Bay is a dynamic site to study nitrification, as seasonal upwelling brings deep water and nutrients into surface waters, which can promote phytoplankton blooms and impact biogeochemical processes such as the nitrogen cycle. We have sampled two sites within Monterey Bay bimonthly for two years as part of the ongoing Monterey Bay Time Series (MBTS) to quantify AOA genes, transcripts, and nitrification rates. Two ecotypes of AOA are routinely found in Monterey Bay - the 'shallow' water column A (WCA) and 'deep' water column B (WCB) clades, which are thought to have distinct physiological properties and can be distinguished based on the amoA gene sequence. Previous work has shown a strong relationship between nitrification rates in Monterey Bay with the abundance of WCA amoA genes and transcripts. Additionally, we found a correlation between the relative abundance of Marine Group I (MGI) Thaumarchaeota 16S rRNA reads (as % of total) and the absolute abundance of AOA amoA genes (determined via qPCR) in Monterey Bay and the California Current System. AOA 16S rRNA gene abundances in turn correlated significantly with changes in nitrification rate with depth, while the relative abundance of genes and transcripts binned to a single AOA (Nitrosopumilus maritimus) was not significantly correlated to nitrification rate. Further analysis of the sequenced AOA

  5. Microbial diversity differences within aerobic granular sludge and activated sludge flocs.

    PubMed

    Winkler, M-K H; Kleerebezem, R; de Bruin, L M M; Verheijen, P J T; Abbas, B; Habermacher, J; van Loosdrecht, M C M

    2013-08-01

    In this study, we investigated during 400 days the microbial community variations as observed from 16S DNA gene DGGE banding patterns from an aerobic granular sludge pilot plant as well as the from a full-scale activated sludge treatment plant in Epe, the Netherlands. Both plants obtained the same wastewater and had the same relative hydraulic variations and run stable over time. For the total bacterial population, a similarity analysis was conducted showing that the community composition of both sludge types was very dissimilar. Despite this difference, general bacterial population of both systems had on average comparable species richness, entropy, and evenness, suggesting that different bacteria were sharing the same functionality. Moreover, multi-dimensional scaling analysis revealed that the microbial populations of the flocculent sludge system moved closely around the initial population, whereas the bacterial population in the aerobic granular sludge moved away from its initial population representing a permanent change. In addition, the ammonium-oxidizing community of both sludge systems was studied in detail showing more unevenness than the general bacterial community. Nitrosomonas was the dominant AOB in flocculent sludge, whereas in granular sludge, Nitrosomonas and Nitrosospira were present in equal amounts. A correlation analysis of process data and microbial data from DGGE gels showed that the microbial diversity shift in ammonium-oxidizing bacteria clearly correlated with fluctuations in temperature. PMID:23064482

  6. Application of forward osmosis (FO) under ultrasonication on sludge thickening of waste activated sludge.

    PubMed

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

    2015-01-01

    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. PMID:26465299

  7. Adsorption of heavy metals on sonicated activated sludge.

    PubMed

    Commenges-Bernole, N; Marguerie, J

    2009-01-01

    The objective of this work is to assess heavy metals fixation capacity on sonicated activated sludge. Ultrasonic treatment of sludge has lead to its desintegration and changes physico-chemical characteristics such as soluble chemical oxygen demand, proteins or particle size distribution. This study has shown that these modifications have improved significantly the capacity of sludge to fix heavy metals. Indeed, after a sonication of 15 min and storage of three days after irradiation, the equilibrium capacity is increased about 45%. The restructuration of sludge during the storage seems to increase the accessibility to active binding sites. PMID:18599337

  8. Microbiology of coke-plant activated sludge

    SciTech Connect

    Owens, J.R.

    1983-01-01

    The biological treatment of coke-plant wastewater represents the most economical means of detoxification and contaminant removal, but little is known about the microbial ecology of this system. Research was therefore undertaken to determine the kinds of microorganisms that survive and function in this environment and to examine the growth patterns that influence treatment efficiency. The microbial flora of coke-plant activated sludge is predominated by populations of aerobic gram negative rods. The principle genera identified were Pseudomonas, Alcaligenes, Flavobacterium and Acinetobacter. The genera Bacillus, Nocardia and Micrococcus were also present at low levels. A single type of rotifer was present along with various protozoans. The ability of microorganisms in coke wastewater to grow on various organic compounds as their sole source of carbon and energy is more restrictive when compared with that of isolates obtained from activated sludge processes treating municipal wastes. The phenol degrading bacteria can be maintained in a continuous culture system with a hydraulic retention time (HRT) of as long as 14 days. Under conditions of increasing HRT the average cell size decreased and the number of cells per milliter increased. As the HRT increased cell yields decreased. At long HRT's (7 to 14 days) cell yields remained constant.

  9. OXYGEN UTILIZATION IN ACTIVATED SLUDGE PLANTS: SIMULATION AND MODEL CALIBRATION

    EPA Science Inventory

    The objective of the research described in the report is to apply recent advances in activated sludge process modeling to the simulation of oxygen utilization rates in full scale activated sludge treatment plants. This is accomplished by calibrating the International Association ...

  10. PARALLEL EVALUATION OF AIR- AND OXYGEN-ACTIVATED SLUDGE

    EPA Science Inventory

    To provide data on the relative merits of air and oxygen in the activated sludge process, two 1900-cu m/day (0.5-mgd) activated sludge pilot plant, one air and one oxygen system, were operated side-by-side at the Joint Water Pollution Control Plant, Carson, California. Both of th...

  11. Filamentous sludge bulking control by nano zero-valent iron in activated sludge treatment systems.

    PubMed

    Xu, Shengnan; Sun, Minghao; Zhang, Chiqian; Surampalli, Rao; Hu, Zhiqiang

    2014-12-01

    Sludge bulking causes loss of biomass in the effluent and deterioration of effluent water quality. This study explored the use of nano zero-valent iron (NZVI with an average particle size of 55 ± 11 nm) for sludge bulking control. In two Modified Ludzack-Ettinger (MLE) activated sludge treatment systems, a single dose of NZVI at the final concentration of 100 mg Fe per L in the mixed liquor reduced the number of filamentous bacteria Type 021N by 2-3 log units (a reduction of 99.9 and 96.7% in MLE tank #1 and #2, respectively). The side effect of the use of NZVI depended on sludge bulking conditions and biomass concentration. In the system with sludge bulking and significant sludge loss (average biomass concentration of 1022 ± 159 COD mg per L or at the ratio of 0.098 g Fe per g biomass COD), the use of NZVI increased effluent COD, NH4(+)-N and NO2(-)-N concentrations, as also evident with the loss of nitrifying populations and nitrifying activities resulting in more than 40 days to have the full recovery of the activated sludge system. In contrast, in the system with the early stages of bulking and the biomass concentration of 1799 ± 113 COD mg per L (at the ratio of 0.056 g Fe per g biomass COD), the effluent water quality and overall bioreactor performance were only slightly affected for a few days. PMID:25386669

  12. Sludge.

    ERIC Educational Resources Information Center

    Tenenbaum, David

    1992-01-01

    Cites a recycling success story involving sludge production from wastewater and transformation into an effective plant fertilizer. Discusses related concerns such as dealing with pollutants like heavy metals and PCBs often found in sludge. Provides an example of an application of sludge produced in Chicago to an area reclamation site. (MCO)

  13. Advanced sludge treatment affects extracellular polymeric substances to improve activated sludge dewatering.

    PubMed

    Neyens, Elisabeth; Baeyens, Jan; Dewil, Raf; De heyder, Bart

    2004-01-30

    The management of wastewater sludge, now often referred to as biosolids, accounts for a major portion of the cost of the wastewater treatment process and represents significant technical challenges. In many wastewater treatment facilities, the bottleneck of the sludge handling system is the dewatering operation. Advanced sludge treatment (AST) processes have been developed in order to improve sludge dewatering and to facilitate handling and ultimate disposal. The authors have extensively reported lab-scale, semi-pilot and pilot investigations on either thermal and thermochemical processes, or chemical oxidation using hydrogen peroxide. To understand the action of these advanced sludge technologies, the essential role played by extracellular polymeric substances (EPS) needs to be understood. EPS form a highly hydrated biofilm matrix, in which the micro-organisms are embedded. Hence they are of considerable importance in the removal of pollutants from wastewater, in bioflocculation, in settling and in dewatering of activated sludge. The present paper reviews the characteristics of EPS and the influence of thermochemical and oxidation mechanisms on degradation and flocculation of EPS. Experimental investigations on waste activated sludge are conducted by the authors to evaluate the various literature findings. From the experiments, it is concluded that AST methods enhance cake dewaterability in two ways: (i) they degrade EPS proteins and polysaccharides reducing the EPS water retention properties; and (ii) they promote flocculation which reduces the amount of fine flocs. PMID:15177096

  14. Production of carboxylates from high rate activated sludge through fermentation.

    PubMed

    Cagnetta, C; Coma, M; Vlaeminck, S E; Rabaey, K

    2016-10-01

    The aim of this work was to study the key parameters affecting fermentation of high rate activated A-sludge to carboxylates, including pH, temperature, inoculum, sludge composition and iron content. The maximum volatile fatty acids production was 141mgCg(-1) VSSfed, at pH 7. Subsequently the potential for carboxylate and methane production for A-sludge from four different plants at pH 7 and 35°C were compared. Initial BOD of the sludge appeared to be key determining carboxylate yield from A-sludge. Whereas methanogenesis could be correlated linearly to the quantity of ferric used for coagulation, fermentation did not show a dependency on iron presence. This difference may enable a strategy whereby A-stage sludge is separated to achieve fermentation, and iron dosing for phosphate removal is only implemented at the B-stage. PMID:27020399

  15. The effect of different aeration conditions in activated sludge--Side-stream system on sludge production, sludge degradation rates, active biomass and extracellular polymeric substances.

    PubMed

    Habermacher, Jonathan; Benetti, Antonio Domingues; Derlon, Nicolas; Morgenroth, Eberhard

    2015-11-15

    On-site minimization of excess sludge production is a relevant strategy for the operation of small-scale and decentralized wastewater treatment plants. In the study, we evaluated the potential of activated sludge systems equipped with side-stream reactors (SSRs). This study especially focused on how the sequential exposure of sludge to different aeration conditions in the side-stream reactors influences the overall degradation of sludge and of its specific fractions (active biomass, extracellular polymeric substances (EPS), EPS proteins, EPS carbohydrates). We found that increasing the solid retention time from 25 to 40 and 80 days enhanced sludge degradation for all aeration conditions tested in the side-stream reactor. Also, the highest specific degradation rate and in turn the lowest sludge production were achieved when maintaining aerobic conditions in the side-stream reactors. The different sludge fractions in terms of active biomass (quantified based on adenosine tri-phosphate (ATP) measurements), EPS proteins and EPS carbohydrates were quantified before and after passage through the SSR. The relative amounts of active biomass and EPS to volatile suspended solids (VSS) did not changed when exposed to different aeration conditions in the SSRs, which indicates that long SRT and starvation in the SSRs did not promote the degradation of a specific sludge fraction. Overall, our study helps to better understand mechanisms of enhanced sludge degradation in systems operated at long SRTs. PMID:26295938

  16. Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization.

    PubMed

    Tiehm, A; Nickel, K; Zellhorn, M; Neis, U

    2001-06-01

    The pretreatment of waste activated sludge by ultrasonic disintegration was studied in order to improve the anaerobic sludge stabilization. The ultrasound frequency was varied within a range from 41 to 3217 kHz. The impact of different ultrasound intensities and treatment times was examined. Sludge disintegration was most significant at low frequencies. Low-frequency ultrasound creates large cavitation bubbles which upon collapse initiate powerful jet streams exerting strong shear forces in the liquid. The decreasing sludge disintegration efficiency observed at higher frequencies was attributed to smaller cavitation bubbles which do not allow the initiation of such strong shear forces. Short sonication times resulted in sludge floc deagglomeration without the destruction of bacteria cells. Longer sonication brought about the break-up of cell walls, the sludge solids were distintegrated and dissolved organic compounds were released. The anaerobic digestion of waste activated sludge following ultrasonic pretreatment causing microbial cell lysis was significantly improved. There was an increase in the volatile solids degradation as well as an increase in the biogas production. The increase in digestion efficiency was proportional to the degree of sludge disintegration. To a lesser degree the deagglomeration of sludge flocs also augmented the anaerobic volatile solids degradation. PMID:11337847

  17. A STUDY OF NITRATE RESPIRATION IN THE ACTIVATED SLUDGE PROCESS

    EPA Science Inventory

    In an experimental, 570-cum/day (0.15-mgd) activated sludge plant treating domestic wastewater from a correctional facility, 76 to 87 percent nitrogen removal was obtained via sludge synthesis and biological denitrification using endogenous H-donors in a compartmentalized reactor...

  18. Can aquatic worms enhance methane production from waste activated sludge?

    PubMed

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

    2016-07-01

    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. PMID:26998797

  19. Enhancement of activated sludge disintegration and dewaterability by Fenton process

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the activated sludge process. In this study, the waste activated sludge was obtained from the campus wastewater treatment plant at Universiti Teknologi PETRONAS (UTP), Malaysia. Fenton pretreatment was optimized by using the response surface methodology (RSM) to study the effects of three operating conditions including the dosage of H2O2 (g H2O2/kg TS), the molar ratio of H2O2/Fe2+ and reaction time. The optimum operating variables to achieve MLVSS removal 65%, CST reduction 28%, sCOD 11000 mg/L and EPS 500 mg/L were: 1000 g H2O2/kg TS, H2O2/Fe2+ molar ratio 70 and reaction time 45 min. Fenton process was proved to be able to enhance the sludge disintegration and dewaterability.

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

    PubMed

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

    2014-12-01

    The management of waste activated sludge (WAS) recycling is a concern that affects the development of the future low-carbon society, particularly sludge reduction and biomass utilization. In this study, we investigated the effect of removing extracellular polymeric substances (EPS), which play important roles in the adhesion and flocculation of WAS, on increased sludge disintegration, thereby enhancing sludge reduction and methane production by anaerobic digestion. EPS removal from WAS by ethylenediaminetetraacetic acid (EDTA) significantly enhanced sludge reduction, i.e., 49 ± 5% compared with 27 ± 1% of the control at the end the digestion process. Methane production was also improved in WAS without EPS by 8881 ± 109 CH4 μmol g(-1) dry-weight of sludge. Microbial activity was determined by denaturing gradient gel electrophoresis and real-time polymerase chain reaction, which showed that the hydrolysis and acetogenesis stages were enhanced by pretreatment with 2% EDTA, with a larger methanogenic community and better methane production. PMID:25277968

  1. Efficiency of the Activated Sludge Model no. 3 for German wastewater on six different WWTPs.

    PubMed

    Wichern, M; Lübken, M; Blömer, R; Rosenwinkel, K H

    2003-01-01

    In 1999, the Activated Sludge Model No. 3 by the IWA Task Group on Mathematical Modelling for the Design and Operation of Biological Wastewater Treatment was presented. The model is used for the simulation of nitrogen removal. The simulations in this paper were done on the basis of a new calibration of the ASM 3 by Koch et al., with the easily degradable COD measured by respiration. For modelling of EBPR the BioP-Module of Rieger et al., was used. Six German wastewater treatment plants were simulated during this research to test the existing set of parameters of the models on various large scale plants. It was shown that changes for nitrification and enhanced biological phosphorus removal in the set of biological parameters were necessary. Sensible parameters and recommended values are presented in this article. Apart from the values of the changed biological parameters, we will in our examination discuss the modelling of the different activated sludge systems and the influent fractioning of the COD. Two plants with simultaneous denitrification in the recirculation ditch (EBPR) are simulated, one with preliminary dentrification, one with intermittent denitrification (EBPR), one with cascade denitrification (EBPR), and one pilot plant according to the Johannesburg-process (EBPR) which was simulated over a period of three months. PMID:12906292

  2. NITRIFICATION AND ARSENIC REMOVAL IN BIOLOGICALLY ACTIVE FILTERS: A CASE STUDY

    EPA Science Inventory

    Ammonia in source waters can cause water treatment and distribution system problems, many of which are associated with biological nitrification. Therefore, in some cases, the removal of ammonia from water is desirable. Biological oxidation of ammonia to nitrate and nitrate (nitr...

  3. NITRIFICATION AND IRON AND ARSENIC REMOVAL IN BIOLOGICALLY ACTIVE FILTERS: A CASE STUDY

    EPA Science Inventory

    Ammonia in source waters can cause water treatment and distribution system problems, many of which are associated with biological nitrification. Therefore, in some cases, the removal of ammonia from water is desirable. Biological oxidation of ammonia to nitrate and nitrate (nitr...

  4. Active heterotrophic biomass and sludge retention time (SRT) as determining factors for biodegradation kinetics of pharmaceuticals in activated sludge.

    PubMed

    Majewsky, Marius; Gallé, Tom; Yargeau, Viviane; Fischer, Klaus

    2011-08-01

    The present study investigates the biodegradation of pharmaceutically active compounds (PhACs) by active biomass in activated sludge. Active heterotrophs (X(bh)) which are known to govern COD removal are suggested as a determining factor for biological PhAC removal as well. Biodegradation kinetics of five polar PhACs were determined in activated sludge of two wastewater treatment plants which differed in size, layout and sludge retention time (SRT). Results showed that active fractions of the total suspended solids (TSS) differed significantly between the two sludges, indicating that TSS does not reveal information about heterotrophic activity. Furthermore, PhAC removal was significantly faster in the presence of high numbers of heterotrophs and a low SRT. Pseudo first-order kinetics were modified to include X(bh) and used to describe decreasing PhAC elimination with increasing SRT. PMID:21652206

  5. Activated sludge process performance using a multistage tower aeration tank

    SciTech Connect

    Shimizu, Tatsuo; Kudo, Kenzo; Nasu, Yoshikazu )

    1993-07-01

    This study's objective was to clarify both experimentally and theoretically whether a vertical multistage tower aeration tank system is advantageous as compared with a completely mixed system, particularly with respect to purification efficiency, sludge settleability, and excess sludge production. In comparing the two systems: (1) purification efficiency in the multistage tower aeration system with partial fluid mixing with a large Peclet number was higher than in a corresponding completely mixed system for all applied organic loadings; (2) the multistage tower aeration system had some definite advantages with respect to sludge settleability and excess sludge production; and (3) the activated sludge system's higher performance with partial fluid mixing was shown quantitatively with the axial dispersion model in conjunction with growth kinetics which involved rapid uptake such as biosorption and subsequent oxidative biodegradation processes of organic substances.

  6. Assessment of denitrifying bacterial composition in activated sludge.

    PubMed

    Srinandan, C S; Shah, Mrinal; Patel, Bhavita; Nerurkar, Anuradha S

    2011-10-01

    The abundance and structure of denitrifying bacterial community in different activated sludge samples were assessed, where the abundance of denitrifying functional genes showed nirS in the range of 10(4)-10(5), nosZ with 10(4)-10(6) and 16S rRNA gene in the range 10(9)-10(10) copy number per ml of sludge. The culturable approach revealed Pseudomonas sp. and Alcaligenes sp. to be numerically high, whereas culture independent method showed betaproteobacteria to dominate the sludge samples. Comamonas sp. and Pseudomonas fluorescens isolates showed efficient denitrification, while Pseudomonas mendocina, Pseudomonas stutzeri and Brevundimonas diminuta accumulated nitrite during denitrification. Numerically dominant RFLP OTUs of the nosZ gene from the fertilizer factory sludge samples clustered with the known isolates of betaproteobacteria. The data also suggests the presence of different truncated denitrifiers with high numbers in sludge habitat. PMID:21868215

  7. Retrofitting activated sludge systems to intermittent aeration for nitrogen removal.

    PubMed

    Hanhan, O; Artan, N; Orhon, D

    2002-01-01

    The paper provides the basis and the conceptual approach of applying process kinetics and modelling to the design of alternating activated sludge systems for retrofitting existing activated sludge plants to intermittent aeration for nitrogen removal. It shows the significant role of the two specific parameters, namely, the aerated fraction and the cycle time ratio on process performance through model simulations and proposes a way to incorporate them into a design procedure using process stoichiometry and mass balance. It illustrates the effect of these parameters, together with the sludge age, in establishing the balance between the denitrification potential and the available nitrogen created in the anoxic/aerobic sequences of system operation. PMID:12420968

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

    PubMed

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

    2016-01-01

    The aim of this study was to investigate the ability of the oxic-settling-anaerobic (OSA)-process and the folic acid addition applied in the activated sludge process to reduce the excess sludge production. The study was monitored during two distinct periods: activated sludge system with OSA-process, and activated sludge system with folic acid addition. The observed sludge yields (Yobs) were 0.30 and 0.08 kgTSS kg(-1) chemical oxygen demand (COD), control phase and OSA-process (period 1); 0.33 and 0.18 kgTSS kg(-1) COD, control phase and folic acid addition (period 2). The Yobs decreased by 73 and 45% in phases with the OSA-process and folic acid addition, respectively, compared with the control phases. The sludge minimization alternatives result in a decrease in excess sludge production, without negatively affecting the performance of the effluent treatment. PMID:26901714

  9. The impact of titanium dioxide nanoparticles on biological nitrogen removal from wastewater and bacterial community shifts in activated sludge.

    PubMed

    Li, Dapeng; Cui, Fuyi; Zhao, Zhiwei; Liu, Dongmei; Xu, Yongpeng; Li, Huiting; Yang, Xiaonan

    2014-04-01

    The potential impact of titanium dioxide nanoparticles (TiO2 NPs) on nitrogen removal from wastewater in activated sludge was investigated using a sequencing batch reactor. The addition of 2-50 mg L(-1) of TiO2 NPs did not adversely affect nitrogen removal. However, when the activated sludge was exposed to 100-200 mg L(-1) of TiO2 NPs, the effluent total nitrogen removal efficiencies were 36.5 % and 20.3 %, respectively, which are markedly lower than the values observed in the control test (80 %). Further studies showed that the decrease in biological nitrogen removal induced by higher concentrations of TiO2 NPs was due to an inhibitory effect on the de-nitrification process. Denaturing gradient gel electrophoresis profiles showed that 200 mg L(-1) of TiO2 NPs significantly reduced microbial diversity in the activated sludge. The effect of light on the antibacterial activity of TiO2 NPs was also investigated, and the results showed that the levels of TiO2-dependent inhibition of biological nitrogen removal were similar under both dark and light conditions. Additional studies revealed that different TiO2 concentrations had a significant effect on dehydrogenase activity, and this effect was most likely the result of decreased microbial activity. PMID:23660752

  10. SLUDGE COMBUSTOR USING SWIRL AND ACTIVE COMBUSTION CONTROL

    EPA Science Inventory

    A research program directed at developing technology for compact shipboard incinerators for sludges is described. The concept utilizes previously developed Vortex Containment Combustor (VCC) as a primary unit with an active combustion control afterburner (AB). The overall power s...

  11. DESIGN HANDBOOK FOR AUTOMATION OF ACTIVATED SLUDGE WASTEWATER TREATMENT PLANTS

    EPA Science Inventory

    This report is a systems engineering handbook for the automation of activated sludge wastewater treatment processes. Process control theory and application are discussed to acquaint the reader with terminology and fundamentals. Successful unit process control strategies currently...

  12. DESIGN PROCEDURES FOR DISSOLVED OXYGEN CONTROL OF ACTIVATED SLUDGE PROCESSES

    EPA Science Inventory

    This report presents design procedures and guidelines for the selection of aeration equipment and dissolved (DO) control systems for activated sludge treatment plants. Aeration methods, equipment and application techniques are examined and selection procedures offered. Various DO...

  13. ENHANCED BIODEGRADATION OF IOPROMIDE AND TRIMETHOPRIM IN NITRIFYING ACTIVATED SLUDGE

    EPA Science Inventory

    Iopromide and trimethoprim are frequently detected pharmaceuticals in effluents of wastewater treatment plants and in surface waters due to their persistence and high usage. Laboratory scale experiments showed that a significantly higher removal rate in nutrifying activated sludg...

  14. Mechanism and design of intermittent aeration activated sludge process for nitrogen removal.

    PubMed

    Hanhan, Oytun; Insel, Güçlü; Yagci, Nevin Ozgur; Artan, Nazik; Orhon, Derin

    2011-01-01

    The paper provided a comprehensive evaluation of the mechanism and design of intermittent aeration activated sludge process for nitrogen removal. Based on the specific character of the process the total cycle time, (T(C)), the aerated fraction, (AF), and the cycle time ratio, (CTR) were defined as major design parameters, aside from the sludge age of the system. Their impact on system performance was evaluated by means of process simulation. A rational design procedure was developed on the basis of basic stochiometry and mass balance related to the oxidation and removal of nitrogen under aerobic and anoxic conditions, which enabled selected of operation parameters of optimum performance. The simulation results indicated that the total nitrogen level could be reduced to a minimum level by appropriate manipulation of the aerated fraction and cycle time ratio. They also showed that the effluent total nitrogen could be lowered to around 4.0 mgN/L by adjusting the dissolved oxygen set-point to 0.5 mg/L, a level which promotes simultaneous nitrification and denitrification. PMID:21104491

  15. Enhanced transformation of tetrabromobisphenol a by nitrifiers in nitrifying activated sludge.

    PubMed

    Li, Fangjie; Jiang, Bingqi; Nastold, Peter; Kolvenbach, Boris Alexander; Chen, Jianqiu; Wang, Lianhong; Guo, Hongyan; Corvini, Philippe François-Xavier; Ji, Rong

    2015-04-01

    The fate of the most commonly used brominated flame retardant, tetrabromobisphenol A (TBBPA), in wastewater treatment plants is obscure. Using a (14)C-tracer, we studied TBBPA transformation in nitrifying activated sludge (NAS). During the 31-day incubation, TBBPA transformation (half-life 10.3 days) was accompanied by mineralization (17% of initial TBBPA). Twelve metabolites, including those with single benzene ring, O-methyl TBBPA ether, and nitro compounds, were identified. When allylthiourea was added to the sludge to completely inhibit nitrification, TBBPA transformation was significantly reduced (half-life 28.9 days), formation of the polar and single-ring metabolites stopped, but O-methylation was not significantly affected. Abiotic experiments confirmed the generation of mono- and dinitro-brominated forms of bisphenol A in NAS by the abiotic nitration of TBBPA by nitrite, a product of ammonia-oxidizing microorganisms (AOMs). Three biotic (type II ipso-substitution, oxidative skeletal cleavage, and O-methylation) and one abiotic (nitro-debromination) pathways were proposed for TBBPA transformation in NAS. Apart from O-methylation, AOMs were involved in three other pathways. Our results are the first to provide information about the complex metabolism of TBBPA in NAS, and they are consistent with a determining role for nitrifiers in TBBPA degradation by initiating its cleavage into single-ring metabolites that are substrates for the growth of heterotrophic bacteria. PMID:25754048

  16. Enhanced aerobic granulation, stabilization, and nitrification in a continuous-flow bioreactor by inoculating biofilms.

    PubMed

    Yang, Yang; Zhou, Dandan; Xu, Zhengxue; Li, Aijun; Gao, Hang; Hou, Dianxun

    2014-06-01

    In this study, the possibility of using backwashed biofilm as seed in an aerobic granular sludge continuous-flow airlift fluidized bed (CAFB) reactor was investigated. After the addition of the inoculated backwashed biofilm, the start-up period of this reactor fed with municipal wastewater was reduced to 25 days, and aerobic granulation and stabilization were enhanced. At steady state, the chemical oxygen demand (COD) removal efficiency and nitrification efficiency were as high as 80-90 and 60 %, respectively. The CAFB was operated continuously and totally for 90 days, and its performance was much more stable when compared with system inoculated with activated sludge. Microbial distribution analyzed by fluorescence in situ hybridization (FISH) showed that the nitrite-oxidizing bacteria (NOB) and ammonium-oxidizing bacteria (AOB) were compatible with heterotrophic bacteria and distributed evenly throughout the granules. Such unique population distribution might be attributed to the low COD level and abundant dissolved oxygen in the entire granule as simulated by the mathematic models. Moreover, scanning electron microscopy revealed broad holes in the granules, which might promote the mass transfer of the nutrients from the surface to the center and enable simultaneous COD removal and nitrification. In conclusion, backwashed biofilm is an alternative seed of the conventional flocculent activated sludge in the aerobic granular sludge system to enhance carbonaceous oxidization and nitrification. PMID:24643735

  17. The digestibility of waste activated sludges.

    PubMed

    Park, Chul; Abu-Orf, Mohammad M; Novak, John T

    2006-01-01

    Laboratory digestion studies using waste activated sludges (WAS) were conducted to compare the digestion performance between anaerobic and aerobic processes. Nine samples of WAS from seven wastewater treatment plants were collected and batch-digested under both anaerobic and aerobic conditions for 30 days at 25 degrees C. The cation content of wastewater (both floc and solution phases) and solution biopolymer (protein and polysaccharide) was measured before and after digestion and compared with volatile solids destruction data. The study revealed that each digestion process was associated with a distinct biopolymer fraction, which accounted for differences in volatile solids reduction under anaerobic and aerobic conditions. The anaerobic digestion data showed strong correlations between soluble protein generation, ammonium production, percent volatile solids reduction, and floc iron (Fe). These data suggest that the amount of volatile solids destroyed by anaerobic digestion depends on the Fe content of floc. In aerobic digestion, polysaccharide accumulated in solution along with calcium and magnesium. For aerobic digestion, correlations between divalent cation release and the production of inorganic nitrogen were found. This implies that divalent cation-bound biopolymer, thought to be lectin-like protein, was the primary organic fraction degraded under aerobic conditions. The results of the study show that the cation content in wastewater is an important indicator of the material that will digest under anaerobic or aerobic conditions and that some of the volatile solids will digest only under either anaerobic or aerobic conditions. PMID:16553167

  18. Effects of metabolic uncouplers on excess sludge reduction and microbial products of activated sludge.

    PubMed

    Fang, Fang; Hu, Hai-Lan; Qin, Min-Min; Xue, Zhao-Xia; Cao, Jia-Shun; Hu, Zhi-Rong

    2015-06-01

    The present study investigated the influences of three metabolic uncouplers (pCP, oCP and oNP) on excess activated sludge reduction and microbial products of extracellular polymeric substances (EPS) and intracellular storage product (polyhydroxybutyrate, PHB) in short-term tests. Results showed sludge was reduced 58.2%, 59.8% and 80.8%, respectively, at pCP, oCP and oNP concentrations of 20mg/L. The dosage of three uncouplers had no obviously influences on COD removal and sludge settleability, but had significant inhibition effect on ammonia removal, especially for oNP. Low concentration of pCP and oNP (5mg/L) dosing resulted in protein and polysaccharide content increased in EPS, however, they were decreased at high pCP and oNP concentrations (>5mg/L). To oCP, the protein content in EPS was increased linearly with oCP concentration. Furthermore, metabolic uncouplers addition stimulated the production of PHB. Among three uncouplers, oCP could be an alternative uncoupler for sludge reduction in activated sludge process. PMID:25746471

  19. Nitrifying bacterial biomass and nitrification activity evaluated by FISH and an automatic on-line instrument at full-scale Fusina (Venice, Italy) WWTP.

    PubMed

    Badoer, S; Miana, P; Della Sala, S; Marchiori, G; Tandoi, V; Di Pippo, F

    2015-12-01

    In this study, monthly variations in biomass of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were analysed over a 1-year period by fluorescence in situ hybridization (FISH) at the full-scale Fusina WWTP. The nitrification capacity of the plant was also monitored using periodic respirometric batch tests and by an automated on-line titrimetric instrument (TITrimetric Automated ANalyser). The percentage of nitrifying bacteria in the plant was the highest in summer and was in the range of 10-15 % of the active biomass. The maximum nitrosation rate varied in the range 2.0-4.0 mg NH4 g(-1) VSS h(-1) (0.048-0.096 kg TKN kg(-1) VSS day(-1)): values obtained by laboratory measurements and the on-line instrument were similar and significantly correlated. The activity measurements provided a valuable tool for estimating the maximum total Kjeldahl nitrogen (TKN) loading possible at the plant and provided an early warning of whether the TKN was approaching its limiting value. The FISH analysis permitted determination of the nitrifying biomass present. The main operational parameter affecting both the population dynamics and the maximum nitrosation activity was mixed liquor volatile suspended solids (MLVSS) concentration and was negatively correlated with ammonia-oxidizing bacteria (AOB) (p = 0.029) and (NOB) (p = 0.01) abundances and positively correlated with maximum nitrosation rates (p = 0.035). Increases in concentrations led to decreases in nitrifying bacteria abundance, but their nitrosation activity was higher. These results demonstrate the importance of MLVSS concentration as key factor in the development and activity of nitrifying communities in wastewater treatment plants (WWTPs). Operational data on VSS and sludge volume index (SVI) values are also presented on 11-year basis observations. PMID:26282437

  20. Biodegradation of plastics in soil and effects on nitrification activity. A laboratory approach

    PubMed Central

    Bettas Ardisson, Giulia; Tosin, Maurizio; Barbale, Marco; Degli-Innocenti, Francesco

    2014-01-01

    The progressive application of new biodegradable plastics in agriculture calls for improved testing approaches to assure their environmental safety. Full biodegradation (≥90%) prevents accumulation in soil, which is the first tier of testing. The application of specific ecotoxicity tests is the second tier of testing needed to show safety for the soil ecosystem. Soil microbial nitrification is widely used as a bioindicator for evaluating the impact of chemicals on soil but it is not applied for evaluating the impact of biodegradable plastics. In this work the International Standard test for biodegradation of plastics in soil (ISO 17556, 2012) was applied both to measure biodegradation and to prepare soil samples needed for a subsequent nitrification test based on another International Standard (ISO 14238, 2012). The plastic mulch film tested in this work showed full biodegradability and no inhibition of the nitrification potential of the soil in comparison with the controls. The laboratory approach suggested in this Technology Report enables (i) to follow the course of biodegradation, (ii) a strict control of variables and environmental conditions, (iii) the application of very high concentrations of test material (to maximize the possible effects). This testing approach could be taken into consideration in improved testing schemes aimed at defining the biodegradability of plastics in soil. PMID:25566223

  1. Sorption and degradation of bisphenol A by aerobic activated sludge.

    PubMed

    Zhao, Junming; Li, Yongmei; Zhang, Chaojie; Zeng, Qingling; Zhou, Qi

    2008-06-30

    Laboratory-scale batch experiments were conducted to investigate the sorption and degradation of bisphenol A (BPA) at microg/L range in an aerobic activated sludge system. The sorption isotherms and thermodynamics indicated that the sorption of BPA on sludge was mainly a physical process in which partitioning played a dominating role. The values of sorption coefficient Koc were between 621 and 736 L/kg in the temperature range of 10-30 degrees C. Both mixed liquor suspended solid (MLSS) and temperature influenced BPA sorption on sludge. The degradation of BPA by acclimated activated sludge could be described by first-order reaction equation with the first-order degradation rate constant of 0.80 h(-1) at 20 degrees C. The decrease of initial COD concentration and the increase of MLSS concentration and temperature enhanced BPA degradation rate. The removal of BPA in the activated sludge system was characterized by a quick sorption on the activated sludge and subsequent biodegradation. PMID:18179868

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

    PubMed

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

    2015-12-01

    A pilot-scale activated sludge bioreactor was filled with immobile carrier to treat high ammonium wastewater. Autotrophic nitrogen elimination occurred rapidly by inoculating nitrifying activated sludge and anammox biofilm. As the ammonium loading rate increased, nitrogen removal rate of 1.2kgNm(-3)d(-1) was obtained with the removal efficiency of 80%. Activated sludge diameter distribution profiles presented two peak values, indicating simultaneous existence of flocculent and granular sludge. Red granular sludge was observed in the reactor. Furthermore, the results of morphological and molecular analysis showed that the characteristics of granular sludge were similar to that of biofilm, while much different from the flocculent sludge. It was assumed granular sludge was formed through the continuous growth and detachment of anammox biofilm. The mechanism of granular sludge formation was discussed and the procedure model was proposed. According to the experimental results, the integrated fixed-biofilm activated sludge reactor provided an alternative to nitrogen removal based on anammox. PMID:25842299

  3. Application of a Novel Functional Gene Microarray to Probe the Functional Ecology of Ammonia Oxidation in Nitrifying Activated Sludge

    PubMed Central

    Short, Michael D.; Abell, Guy C. J.; Bodrossy, Levente; van den Akker, Ben

    2013-01-01

    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. PMID:24155925

  4. Cometabolic degradation of organic wastewater micropollutants by activated sludge and sludge-inherent microorganisms.

    PubMed

    Fischer, Klaus; Majewsky, Marius

    2014-08-01

    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. PMID:24866947

  5. Treatment of coke-oven wastewater with the powdered activated carbon-contact stabilization activated sludge process. Final report

    SciTech Connect

    Suidan, M.T.; Deady, M.A.; Gee, C.S.

    1983-11-01

    The objective of the study was to determine optimum parameters for the operation of an innovative process train used in the treatment of coke-over wastewater. The treatment process train consisted of a contact-stabilization activated sludge system with powdered activated carbon (PAC) addition, followed by activated sludge nitrification, followed by denitrification in an anoxic filter. The control and operating parameters evaluated during the study were: (a) the average mixed-liquor PAC concentration maintained in the contact-stabilization system, (b) the solids retention time practiced in the contact-stabilization system, and (c) the hydraulic detention time maintained in the contact aeration tank. Three identical treatement process trains were constructed and employed in this study. The coke-oven wastewater used for this investigation was fed to the treatment units at 30% strength. The first part of the study was devoted to determining the interactions between the mixed liquor PAC concentration and the solids retention time in the contact-stabilization tanks. Results showed that optimum overall system performance is attainable when the highest sludge age (30 day) and highest mixed liquor PAC concentration were practiced. During the second phase of the study, all three systems were operated at a 30 day solids retention time while different detention times of 1, 2/3 and 1/3 day were evaluated in the contact tank. PAC addition rates were maintained at the former levels and, consequently, reduced contact times entailed higher mixed liquor carbon concentrations. Once again, the system receiving the highest PAC addition rate of PAC exhibited the best overall performance. This system exhibited no deterioration in process performance as a result of decreased contact detention time. 72 references, 41 figures, 24 tables.

  6. Role of nitrification in the biodegradation of selected artificial sweetening agents in biological wastewater treatment process.

    PubMed

    Tran, N H; Nguyen, V T; Urase, T; Ngo, H H

    2014-06-01

    The biodegradation of the six artificial sweetening agents including acesulfame (ACE), aspartame (ASP), cyclamate (CYC), neohesperidindihydrochalcone (NHDC), saccharin (SAC), and sucralose (SUC) by nitrifying activated sludge was first examined. Experimental results showed that ASP and NHDC were the most easily degradable compounds even in the control tests. CYC and SAC were efficiently biodegraded by the nitrifying activated sludge, whereas ACE and SUC were poorly removed. However, the biodegradation efficiencies of the ASs were increased with the increase in initial ammonium concentrations in the bioreactors. The association between nitrification and co-metabolic degradation was investigated and a linear relationship between nitrification rate and co-metabolic biodegradation rate was observed for the target artificial sweeteners (ASs). The contribution of heterotrophic microorganisms and autotrophic ammonia oxidizers in biodegradation of the ASs was elucidated, of which autotrophic ammonia oxidizers played an important role in the biodegradation of the ASs, particularly with regards to ACE and SUC. PMID:24681682

  7. Fate of malathion and a phosphonic acid in activated sludge with varying solids retention times.

    PubMed

    Janeczko, Allen K; Walters, Edward B; Schuldt, Steven J; Magnuson, Matthew L; Willison, Stuart A; Brown, Lisa M; Ruiz, Oscar N; Felker, Daniel L; Racz, LeeAnn

    2014-06-15

    This study examined the ability of activated sludge (AS) to sorb and biodegrade ethylmethylphosphonic acid (EMPA) and malathion, a degradation product and surrogate, respectively, for an organophosphate chemical warfare agent. Sorption equilibrium isotherm experiments indicate that sorption of EMPA and malathion to AS is negligible. EMPA at a concentration of 1 mg L(-1) degraded by approximately 30% with apparent first-order kinetics, possibly via co-metabolism from nitrification. Heterotrophic bacteria and abiotic mechanisms, however, are largely responsible for malathion degradation also with apparent first-order kinetics. EMPA did not inhibit chemical oxygen demand (COD) oxidation or nitrification activity, although malathion did appear to induce a stress response resulting in inhibition of COD oxidation. The study also included a 30-day experiment in which malathion, at a concentration of 5 mg L(-1), was repeatedly fed to AS in bench-scale sequencing batch reactors (SBRs) operating at different solids retention times (SRTs). Peak malathion concentrations occurred at day 4.5, with the longer SRTs yielding greater peak malathion concentrations. The AS reduced the malathion concentrations to nearly zero by day 10 for all SRTs, even when the malathion concentration in the influent increased to 20.8 mg L(-1). The data suggest a biodegradation pathway for malathion involving an oxygenase. Phylogenetic analyses revealed that all samples had an abundance of Zoogloea, though there was greater bacterial diversity in the SBR with the SRT of 50 days. The SBR with an SRT of 9.5 days had an apparent reduction in the diversity of the bacterial community. PMID:24709533

  8. Restoring nitrification and COD removal at a refinery in the Southwest

    SciTech Connect

    Dyke, P.M.; Lucas, G.F.; Christiansen, J.A.; Smith, C.R.

    1995-12-31

    During the month of April 1993, a Southwest Texas refinery experienced a loss of nitrification and Chemical Oxygen Demand (COD) removal capacity in their activated sludge system following several consecutive days of high COD loadings. This resulted in excessive effluent ammonia (NH{sup 3}) and COD levels approaching permit levels. International Biochemical Group-Microbe Masters (Microbe Masters) was brought into the plant at the end of April to assess the situation and provide recommendations to quickly restore nitrification and COD removal. The bioaugmentation program employed at this refinery achieved the following results: (1) restoration of complete nitrification in thirteen days; (2) a 17% increase in COD removal efficiency; and (3) improved plant/operator knowledge of biological system health and performance critical to maintaining optimum BOD, COD and NH{sub 3} removal.

  9. Polyhydroxyalkanoate production potential of heterotrophic bacteria in activated sludge.

    PubMed

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

    2016-01-01

    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. PMID:26071670

  10. Anaerobic bioleaching of metals from waste activated sludge.

    PubMed

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

    2015-05-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g(-1) of copper, 487 μg g(-1) of lead, 793 μg g(-1) of zinc, 27 μg g(-1) of nickel and 2.3 μg g(-1) of cadmium. During the anaerobic acidification of 3 gdry weight L(-1) waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. PMID:25659306

  11. The first metagenome of activated sludge from full-scale anaerobic/anoxic/oxic (A2O) nitrogen and phosphorus removal reactor using Illumina sequencing.

    PubMed

    Tian, Mei; Zhao, Fangqing; Shen, Xin; Chu, Kahou; Wang, Jinfeng; Chen, Shuai; Guo, Yan; Liu, Hanhu

    2015-09-01

    The anaerobic/anoxic/oxic (A2O) process is globally one of the widely used biological sewage treatment processes. This is the first report of a metagenomic analysis using Illumina sequencing of full-scale A2O sludge from a municipal sewage treatment plant. With more than 530,000 clean reads from different taxa and metabolic categories, the metagenome results allow us to gain insight into the functioning of the biological community of the A2O sludge. There are 51 phyla and nearly 900 genera identified from the A2O activated sludge ecosystem. Proteobacteria, Bacteroidetes, Nitrospirae and Chloroflexi are predominant phyla in the activated sludge, suggesting that these organisms play key roles in the biodegradation processes in the A2O sewage treatment system. Nitrospira, Thauera, Dechloromonas and Ignavibacterium, which have abilities to metabolize nitrogen and aromatic compounds, are most prevalent genera. The percent of nitrogen and phosphorus metabolism in the A2O sludge is 2.72% and 1.48%, respectively. In the current A2O sludge, the proportion of Candidatus Accumulibacter is 1.37%, which is several times more than that reported in a recent study of A2O sludge. Among the four processes of nitrogen metabolism, denitrification related genes had the highest number of sequences (76.74%), followed by ammonification (15.77%), nitrogen fixation (3.88%) and nitrification (3.61%). In phylum Planctomycetes, four genera (Planctomyces, Pirellula, Gemmata and Singulisphaera) are included in the top 30 abundant genera, suggesting the key role of ANAMMOX in nitrogen metabolism in the A2O sludge. PMID:26354707

  12. Fate and toxicity of melamine in activated sludge treatment systems after a long-term sludge adaptation.

    PubMed

    Xu, Shengnan; Zhang, Yanyan; Sims, Atreyee; Bernards, Matthew; Hu, Zhiqiang

    2013-05-01

    Melamine is a nitrogen-rich (67% nitrogen by mass) heterocyclic aromatic compound that could significantly increase effluent total nitrogen concentrations. In this study, we investigated the degradation of melamine and its impact on activated sludge operations by employing two common activated sludge processes, namely the Modified Ludzack-Ettinger (MLE) process and the continuous stirred tank reactor (CSTR) process. Melamine was dosed continuously from day 125 in both activated sludge treatment systems at an influent concentration of 3 mg/L for about 100 days. Even after such a long period of sludge adaptation, melamine appeared not to be easily biodegradable. The average melamine removal efficiencies in the CSTR and MLE systems were 14 ± 10% and 20 ± 15%, respectively. There was no significant difference in melamine removal between the two different activated sludge processes. The long-term input of melamine resulted in a decrease in the nitrifying bacterial activities (by 82 ± 8%) and population in both systems. Short-term microtiter assay results also showed that melamine reduced activated sludge growth by 80% when supplied at a concentration of 75.6 mg/L. These results suggest that sludge adaptation plays a minimal role in melamine degradation, as the enzymes responsible for hydrolytic deamination of melamine in activated sludge are not easily induced. The insignificant biodegradation of melamine is also attributed to bacterial growth inhibition under long-term dosing conditions with melamine, resulting in a significant decrease in effluent water quality. PMID:23466035

  13. Nonoxidative removal of organics in the activated sludge process

    PubMed Central

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

    2016-01-01

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

  14. Degradation of mono-fluorophenols by an acclimated activated sludge.

    PubMed

    Chaojie, Zhang; Qi, Zhou; Ling, Chen; Yuan, Yuan; Hui, Yu

    2007-02-01

    Acclimated activated sludge was examined for its ability to degrade mono-fluorophenols as the sole carbon source in aerobic batch cultures. The acclimated activated sludge degraded fluorophenol efficiently. It degraded 100 mg/l 3-fluoropheno and 4-fluorophenol in 16 h with, respectively, 99.85% and 99.91% fluoride anion release and it degraded 50 mg/l 2-fluorophenol in 15 h with 99.26% fluoride anion release. The aerobic biodegradability of the mono-fluorophenols decreased in the order: 4-fluorophenol > 3-fluorophenol > 2-fluorophenol, resulting mainly from a different octanol/water partition coefficient and different steric parameter of the fluorophenols. The mechanism study revealed that the initial step in the aerobic biodegradation of mono-fluorophenols by the activated sludge was their transformation to fluorocatechol. Following transformation of the fluorophenol to fluorocatechol, ring cleavage by catechol 1, 2-dioxygenases proceeded via an ortho-cleavage pathway, then defluorination occurred. PMID:16819592

  15. Increased salinity improves the thermotolerance of mesophilic nitrification.

    PubMed

    Courtens, Emilie N P; Boon, Nico; De Schryver, Peter; Vlaeminck, Siegfried E

    2014-05-01

    Nitrification is a well-studied and established process to treat ammonia in wastewater. Although thermophilic nitrification could avoid cooling costs for the treatment of warm wastewaters, applications above 40 °C remain a significant challenge. This study tested the effect of salinity on the thermotolerance of mesophilic nitrifying sludge (34 °C). In batch tests, 5 g NaCl L(-1) increased the activity of aerobic ammonia-oxidizing bacteria (AerAOB) by 20-21 % at 40 and 45 °C. For nitrite-oxidizing bacteria (NOB), the activity remained unaltered at 40 °C, yet decreased by 83 % at 45 °C. In a subsequent long-term continuous reactor test, temperature was increased from 34 to 40, 42.5, 45, 47.5 and 50 °C. The AerAOB activity showed 65 and 37 % higher immediate resilience in the salt reactor (7.5 g NaCl L(-1)) for the first two temperature transitions and lost activity from 45 °C onwards. NOB activity, in contrast to the batch tests, was 37 and 21 % more resilient in the salt reactor for the first two transitions, while no difference was observed for the third temperature transition. The control reactor lost NOB activity at 47.5 °C, while the salt reactor only lost activity at 50 °C. Overall, this study demonstrates salt amendment as a tool for a more efficient temperature transition for mesophilic sludge (34 °C) and eventually higher nitrification temperatures. PMID:24526362

  16. Photo-oxygenation to support nitrification in an algal-bacterial consortium treating artificial wastewater.

    PubMed

    Karya, N G A I; van der Steen, N P; Lens, P N L

    2013-04-01

    Oxygenation by photosynthesis in a mixed culture of algae and nitrifiers was investigated for its potential to support nitrification. An open photo-bioreactor (1L fermentor; 30°C) was inoculated with an enriched culture of nitrifiers obtained from activated sludge and a pure culture of Scenedesmus sp. The reactor was illuminated (60 μmol/m2 s) and operated as a sequencing batch reactor with 50% discharge per cycle and sludge retention time of 15 or 30 days. Full nitrification of synthetic wastewater (50 mgNH4+-N/L) without mechanical aeration was achieved after less than 14 cycles (18.5 h React per 24h cycle) and the biomass steadily increased until a concentration of 1.9 g VSS/L with 29 mg chl-a/L. The maximum observed nitrification rate was 7.7 mgNH4+-N/Lh. A mass balance showed that ammonium removal was primarily by nitrification (81-85%) rather than by ammonium uptake by algae. PMID:23500581

  17. Activated sludge acclimatisation kinetics to non-ionic surfactants.

    PubMed

    Carvalho, G; Novais, J M; Pinheiro, H M

    2003-01-01

    The biodegradation of surfactants is a frequent and complex problem in domestic and industrial wastewater treatment processes. In addition to the resulting metabolites being sometimes refractory, the complete biodegradation of many of the most employed non-ionic surfactants requires long hydraulic retention times and the presence of specialised bacterial consortia. Preliminary acclimatisation tests highlighted the importance of the sludge acclimatisation state to a specific surfactant substrate for biotreatment efficiency. This paper reports on studies aimed at quantifying activated sludge acclimatisation and memory retention levels when subjected to changes in the type of surfactant included in the feed. Several transitions were tested, namely from an alkylphenol ethoxylate to a linear alkyl ethoxylate and the reverse, and between alkyl ethoxylates with different hydrophobic and hydrophilic molecular chain lengths. The kinetic results showed that sludge activation and memory loss were more dynamic for primary biodegradation It was found that the sludge was harder to adapt to alkylphenol ethoxylate than to alkyl ethoxylate. The former also apparently introduced an inhibitory effect, resulting in very slow degradation kinetics when imposed to alkyl ethoxylate acclimatised sludge. When replacing an alkyl ethoxylate with another surfactant of the same family, a longer ethoxylate chain reduced the degradation rates. This effect was further enhanced by simultaneously increasing the hydrophobic chain length of the substrate. The acclimatisation kinetic after the replacement of an alkyl ethoxylate by a longer counterpart was slower than the reverse case, and memory was also more easily lost. PMID:12641258

  18. Landfill leachate characterization for simulation of biological treatment with Activated Sludge Model No. 1 and Activated Sludge Model No. 3.

    PubMed

    Galleguillos, Marcelo; Vasel, Jean-Luc

    2011-01-01

    Landfill leachates can be characterized correctly in terms of Activated Sludge Model No. 1 (ASM1) and Activated Sludge Model No. 3 (ASM3) variables. The wastewater characterization of leachate from a Luxembourg landfill was based on a physical-chemical method combined with a BOD analysis for the COD fractions and on standard analysis for forms of nitrogen. The results show important differences compared with municipal wastewater. High amounts of organic matter with low biodegradability were found, as well as a high concentration of ammonium nitrogen. Based on average values, a generic ASM characterization is proposed for landfill leachates. It can be directly employed in the early stages of the simulation of landfill leachate treatment with activated sludge models. PMID:21970168

  19. Bioaugmentation as a Tool To Protect the Structure and Function of an Activated-Sludge Microbial Community against a 3-Chloroaniline Shock Load

    PubMed Central

    Boon, Nico; Top, Eva M.; Verstraete, Willy; Siciliano, Steven D.

    2003-01-01

    Bioaugmentation of bioreactors focuses on the removal of xenobiotics, with little attention typically paid to the recovery of disrupted reactor functions such as ammonium-nitrogen removal. Chloroanilines are widely used in industry as a precursor to a variety of products and are occasionally released into wastewater streams. This work evaluated the effects on activated-sludge reactor functions of a 3-chloroaniline (3-CA) pulse and bioaugmentation by inoculation with the 3-CA-degrading strain Comamonas testosteroni I2 gfp. Changes in functions such as nitrification, carbon removal, and sludge compaction were studied in relation to the sludge community structure, in particular the nitrifying populations. Denaturing gradient gel electrophoresis (DGGE), real-time PCR, and fluorescent in situ hybridization (FISH) were used to characterize and enumerate the ammonia-oxidizing microbial community immediately after a 3-CA shock load. Two days after the 3-CA shock, ammonium accumulated, and the nitrification activity did not recover over a 12-day period in the nonbioaugmented reactors. In contrast, nitrification in the bioaugmented reactor started to recover on day 4. The DGGE patterns and the FISH and real-time PCR data showed that the ammonia-oxidizing microbial community of the bioaugmented reactor recovered in structure, activity, and abundance, while the number of ribosomes of the ammonia oxidizers in the nonbioaugmented reactor decreased drastically and the community composition changed and did not recover. The settleability of the activated sludge was negatively influenced by the 3-CA addition, with the sludge volume index increasing by a factor of 2.3. Two days after the 3-CA shock in the nonbioaugmented reactor, chemical oxygen demand (COD) removal efficiency decreased by 36% but recovered fully by day 4. In contrast, in the bioaugmented reactor, no decrease of the COD removal efficiency was observed. This study demonstrates that bioaugmentation of wastewater

  20. Nitrification of industrial and domestic saline wastewaters in moving bed biofilm reactor and sequencing batch reactor.

    PubMed

    Bassin, João P; Dezotti, Marcia; Sant'anna, Geraldo L

    2011-01-15

    Nitrification of saline wastewaters was investigated in bench-scale moving-bed biofilm reactors (MBBR). Wastewater from a chemical industry and domestic sewage, both treated by the activated sludge process, were fed to moving-bed reactors. The industrial wastewater contained 8000 mg Cl(-)/L and the salinity of the treated sewage was gradually increased until that level. Residual substances present in the treated industrial wastewater had a strong inhibitory effect on the nitrification process. Assays to determine inhibitory effects were performed with the industrial wastewater, which was submitted to ozonation and carbon adsorption pretreatments. The latter treatment was effective for dissolved organic carbon (DOC) removal and improved nitrification efficiency. Nitrification percentage of the treated domestic sewage was higher than 90% for all tested chloride concentrations up to 8000 mg/L. Results obtained in a sequencing batch reactor (SBR) were consistent with those attained in the MBBR systems, allowing tertiary nitrification and providing adequate conditions for adaptation of nitrifying microorganisms even under stressing and inhibitory conditions. PMID:20933327

  1. THE EFFECT OF POWERED ACTIVATED CARBON IN A PETROLEUM REFINERY ACTIVATED SLUDGE TREATMENT SYSTEM

    EPA Science Inventory

    The purpose of this research program was to determine the effect of the addition of powdered activated carbon (PAC) to refinery activated sludge systems. Bench-scale and full-scale tests were performed. A wide range of PAC concentrations and sludge ages were evaluated. Bench-scal...

  2. EVALUATION OF FULL SCALE ACTIVATED SLUDGE SYSTEMS UTILIZING POWDERED ACTIVATED CARBON ADDITION WITH WET AIR REGENERATION

    EPA Science Inventory

    The addition of powdered activated carbon (PAC) to activated sludge systems is a proven method of wastewater treatment. Of eleven POTWs in the U.S. that were designed for PAC use, ten included wet air regeneration (WAR) for the destruction of secondary sludge solids and recovery ...

  3. Microscopic Analysis of Plankton, Periphyton, and Activated Sludge. Training Manual.

    ERIC Educational Resources Information Center

    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…

  4. Basic Activated Sludge. Training Module 2.115.2.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts, and transparency masters. This is the first of a three module series and considers definition of terms, design…

  5. Intermediate Activated Sludge. Training Module 2.116.3.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts and transparency masters. This is the second level of a three module series and considers aeration devices,…

  6. TOP-FEED VACUUM FILTRATION OF WASTE-ACTIVATED SLUDGE

    EPA Science Inventory

    A side-by-side comparison of a conventional bottom-feed vacuum filter and a prototype top-feed vacuum filter was conducted. Thickened, waste-activated sludge at approximately 1.8 percent feed solids concentration and conditioned with ferric chloride was dewatered on two filters 1...

  7. SAFETY ASPECTS OF OXYGEN AERATION ACTIVATED SLUDGE SYSTEMS

    EPA Science Inventory

    This project was carried out to assess the impact of the use of oxygen and oxygen-enriched air for aeration of activated sludge systems on the safety of municipal waste-water treatment plants and their personnel. The tasks included (1) determination of oxygen combustion hazards f...

  8. ACTIVATED SLUDGE CLARIFIERS: DESIGN REQUIREMENTS AND RESEARCH PRIORITIES

    EPA Science Inventory

    The literature review of 320 references was conducted in an EPA-funded project to identify the needs for further research on activated sludge clarifier design and performance. The findings were summarized in a report and used as a basis of a 3-day research needs symposium. The pr...

  9. EVALUATION OF AN ACTIVATED SLUDGE SECONDARY CLARIFIER DISTRIBUTED INLET

    EPA Science Inventory

    Secondary clarifiers are crucial to the overall performance of the activated sludge process. Research over the last 40 years indicates that density currents are factors which degrade clarifier performance when not considered in design. However, present designs of most center-feed...

  10. FEASIBILITY OF TREATING SEPTIC TANK WASTE BY ACTIVATED SLUDGE

    EPA Science Inventory

    The objective of the study reported herein was to evaluate the impact of household septic tank wastes on municipal activated sludge treatment plants. Septage addition was evaluated on a continuous basis over a four-month period in a 7500 l/day (1980 gpd) pilot plant. The septage ...

  11. Fate and effects of methylene chloride in activated sludge.

    PubMed

    Klecka, G M

    1982-09-01

    Activated sludge obtained from a municipal wastewater treatment plant was acclimated to methylene chloride at concentrations between 1 and 100 mg/liter by continuous exposure to the compound for 9 to 11 days. Acclimated cultures were shown to mineralize methylene chloride to carbon dioxide and chloride. Rates of methylene chloride degradation were 0.14, 2.3, and 7.4 mg of CH2Cl2 consumed per h per g of mixed-liquor suspended solids for cultures incubated in the presence of 1, 10, and 100 mg/liter, respectively. Concentrations of methylene chloride between 10 and 1,000 mg/liter had no significant effect on O2 consumption or glucose metabolism by activated sludge. A hypothetical model was developed to examine the significance of volatilization and biodegradation for the removal of methylene chloride from an activated sludge reactor. Application of the model indicated that the rate of biodegradation was approximately 12 times greater than the rate of volatilization. Thus, biodegradation may be the predominant process determining the fate of methylene chloride in activated sludge systems continuously exposed to the compound. PMID:7138008

  12. Operational Control Procedures for the Activated Sludge Process: Appendix.

    ERIC Educational Resources Information Center

    West, Alfred W.

    This document is the appendix for a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. Categories discussed include: control test data, trend charts, moving averages, semi-logarithmic plots, probability…

  13. Advanced Activated Sludge. Training Module 2.117.4.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts and transparency masters. This is the third level of a three module series and considers design and operation…

  14. Activated Sludge. Instructor's Guide. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Boe, Owen K.

    This instructor's guide contains the materials needed to teach a seven-lesson unit on activated sludge. These materials include an overview of the unit, lesson plans, lecture outlines (keyed to slides designed for use with the lessons), student worksheets for each of the seven lessons (with answers), and two copies of a final quiz (with and…

  15. Fate and effects of methylene chloride in activated sludge.

    PubMed Central

    Klecka, G M

    1982-01-01

    Activated sludge obtained from a municipal wastewater treatment plant was acclimated to methylene chloride at concentrations between 1 and 100 mg/liter by continuous exposure to the compound for 9 to 11 days. Acclimated cultures were shown to mineralize methylene chloride to carbon dioxide and chloride. Rates of methylene chloride degradation were 0.14, 2.3, and 7.4 mg of CH2Cl2 consumed per h per g of mixed-liquor suspended solids for cultures incubated in the presence of 1, 10, and 100 mg/liter, respectively. Concentrations of methylene chloride between 10 and 1,000 mg/liter had no significant effect on O2 consumption or glucose metabolism by activated sludge. A hypothetical model was developed to examine the significance of volatilization and biodegradation for the removal of methylene chloride from an activated sludge reactor. Application of the model indicated that the rate of biodegradation was approximately 12 times greater than the rate of volatilization. Thus, biodegradation may be the predominant process determining the fate of methylene chloride in activated sludge systems continuously exposed to the compound. PMID:7138008

  16. PILOT PLANT EVALUATION OF ALTERNATIVE ACTIVATED SLUDGE SYSTEMS

    EPA Science Inventory

    Step feed, plug flow and complete mix activated sludge systems were compared on a pilot plant scale under similar operating conditions with the same municipal wastewater. The process loading to each system was varied over a wide range during the course of the investigation. Exten...

  17. BIOLOGICALLY ENHANCED OXYGEN TRANSFER IN THE ACTIVATED SLUDGE PROCESS (JOURNAL)

    EPA Science Inventory

    Biologically enhanced oxgyen transfer has been a hypothesis to explain observed oxygen transfer rates in activated sludge systems that were well above that predicted from aerator clean-water testing. The enhanced oxygen transfer rates were based on tests using BOD bottle oxygen ...

  18. Heavy metals and adsorbents effects on activated sludge microorganisms.

    PubMed

    Ong, S A; Lim, P E; Seng, C E

    2004-01-01

    The sorption of Cu(II) and Cd(II) from synthetic solution by powdered activated carbon (PAC), biomass, rice husk (RH) and activated rice husk (ARH) were investigate under batch conditions. After activated by concentrated nitric acid for 15 hours at 60-65 degrees C, the adsorption capacity for RH was increased. The adsorbents arranged in the increasing order of adsorption capacities to the Langmuir Q degree parameter were biomass > PAC > ARH > RH. The addition of adsorbents in base mix solution had increased the specific oxygen uptake rate (SOUR) activated sludge microorganisms with and without the presence of metals. The increased of SOUR were due to the ability of PAC and RH in reducing the inhibitory effect of metals on microorganisms and provide a reaction site between activated sludge microorganisms and substrates. PMID:15141467

  19. Molecular characterization of activated sludge from a seawater‐processing wastewater treatment plant

    PubMed Central

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

    2011-01-01

    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

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

    PubMed

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

    2015-10-15

    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

  1. The shift of the microbial community in activated sludge with calcium treatment and its implication to sludge settleability.

    PubMed

    Ye, Chengchen; Yang, Xinping; Zhao, Fang-Jie; Ren, Lifei

    2016-05-01

    The sludge settleability is of prime importance for the activated sludge process. The effect of calcium ion on the biological performance of sludge was investigated in a lab-scale activated sludge system with varying Ca(2+) concentration. Results indicated that addition of 150mg/L Ca(2+) to the influent significantly improved the settling characteristics and metabolic reactivity of activated sludge in the bioreactors. Analyses using denaturing gradient gel electrophoresis (DGGE) and 16S rRNA sequencing showed that a significant difference in the presence of certain bacterial groups between the sludge systems with 150mg/L Ca(2+) and those with 0-100mg/L Ca(2+) addition. Ca(2+) also increased the production of the extracellular polymeric substance (EPS) and facilitated the development of microbial cluster in the bioreactor. Study showed that an addition of 150mg/L Ca(2+) to the influent provides a simple approach to improve the settling properties of activated sludge and maintain high pollutant removal efficiency. PMID:26868150

  2. Treatment of a submerged anaerobic membrane bioreactor (SAnMBR) effluent by an activated sludge system: the role of sulphide and thiosulphate in the process.

    PubMed

    Sánchez-Ramírez, J E; Seco, A; Ferrer, J; Bouzas, A; García-Usach, F

    2015-01-01

    This work studies the use of a well-known and spread activated sludge system (UCT configuration) to treat the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) treating domestic wastewater. Ammonia, phosphate, dissolved methane and sulphide concentrations in the SAnMBR effluent were around 55 mg NH4-N L(-1), 7 mg PO4-P L(-1), 30 mg non-methane biodegradable COD L(-1), and 105 mg S(2-) L(-1) respectively. The results showed a nitrification inhibition caused by the presence of sulphur compounds at any of the solids retention time (SRT) studied (15, 20 and 25 days). This inhibition could be overcome increasing the hydraulic retention time (HRT) from 13 to 26 h. Among the sulphur compounds, sulphide was identified as the substance which caused the nitrification inhibition. When the nitrification was well established, removal rates of nitrogen and phosphorus of 56% and 45% were reached respectively. The sulphide present in the influent was completely oxidised to sulphate, contributing this oxidation to the denitrification process. Moreover, the presence of methanotrophic bacteria, detected by FISH technique, could also contribute to the denitrification. PMID:25239686

  3. EVALUATION OF ACTIVATED BIOFILTRATION AND ACTIVATED BIOFILTRATION/ACTIVATED SLUDGE TECHNOLOGIES

    EPA Science Inventory

    The paper presents the results of a review and investigation of the activated biofilter (ABF) and activated biofilter/activated sludge (ABF/AS) technologies and a review of operating records of several municipal plants in the U.S. using these technologies. The overall objective o...

  4. Improve bio-activity of anaerobic sludge by low energy ultrasound.

    PubMed

    Zhu, Yichun; Li, Xin; Du, Maoan; Liu, Zuwen; Luo, Hui; Zhang, Tao

    2015-01-01

    This research focused on ultrasound-enhanced bio-activity of anaerobic sludge. Low energy ultrasound irradiation can increase the bio-activity of anaerobic sludge. Ultrasonic parameter, characteristics of anaerobic sludge and experimental conditions are important parameters which affect the enhancement effect on anaerobic sludge. In order to assess the effects of characteristics of anaerobic sludge and experimental conditions on ultrasonic irradiation of anaerobic sludge, experiments with different characteristics of anaerobic sludge were carried out and analyzed with the content of coenzyme F420 and dehydrogenase activity (DHA). The results showed that anaerobic sludge bio-activity was impacted by the initial temperature, initial chemical oxygen demand (COD), sludge concentration, and stirring during the ultrasonic process. Optimal performance was achieved when sound frequency, power density, and ultrasonic irradiation period was 20 kHz, 0.1 W/mL, and 10 min, respectively, under which the wastewater COD removal efficiency was increased by 12.9 percentage points. The results indicated that low temperature could affect the anaerobic sludge irradiation effect, while intermittent stirring could enhance the bio-activity of anaerobic sludge irradiation effect and low substrate concentration improved anaerobic sludge activity by ultrasound. PMID:26676010

  5. Complete nitrification by Nitrospira bacteria.

    PubMed

    Daims, Holger; Lebedeva, Elena V; Pjevac, Petra; Han, Ping; Herbold, Craig; Albertsen, Mads; Jehmlich, Nico; Palatinszky, Marton; Vierheilig, Julia; Bulaev, Alexandr; Kirkegaard, Rasmus H; von Bergen, Martin; Rattei, Thomas; Bendinger, Bernd; Nielsen, Per H; Wagner, Michael

    2015-12-24

    Nitrification, the oxidation of ammonia via nitrite to nitrate, has always been considered to be a two-step process catalysed by chemolithoautotrophic microorganisms oxidizing either ammonia or nitrite. No known nitrifier carries out both steps, although complete nitrification should be energetically advantageous. This functional separation has puzzled microbiologists for a century. Here we report on the discovery and cultivation of a completely nitrifying bacterium from the genus Nitrospira, a globally distributed group of nitrite oxidizers. The genome of this chemolithoautotrophic organism encodes the pathways both for ammonia and nitrite oxidation, which are concomitantly activated during growth by ammonia oxidation to nitrate. Genes affiliated with the phylogenetically distinct ammonia monooxygenase and hydroxylamine dehydrogenase genes of Nitrospira are present in many environments and were retrieved on Nitrospira-contigs in new metagenomes from engineered systems. These findings fundamentally change our picture of nitrification and point to completely nitrifying Nitrospira as key components of nitrogen-cycling microbial communities. PMID:26610024

  6. Suitability of Sludge Biotic Index (SBI), Sludge Index (SI) and filamentous bacteria analysis for assessing activated sludge process performance: the case of piggery slaughterhouse wastewater.

    PubMed

    Pedrazzani, Roberta; Menoni, Laura; Nembrini, Stefano; Manili, Livia; Bertanza, Giorgio

    2016-07-01

    Piggery slaughterhouse wastewater poses serious issues in terms of disposal feasibility and environmental impact, due to its huge organic load and variability. It is commonly treated by means of activated sludge processes, whose performance, in case of municipal wastewater, can be monitored by means of specific analyses, such as Sludge Biotic Index (SBI), Sludge Index (SI) and floc and filamentous bacteria observation. Therefore, this paper was aimed at assessing the applicability of these techniques to piggery slaughterhouse sewage. A plant located in Northern Italy was monitored for 1 year. Physical, chemical and operation parameters were measured; the activated sludge community (ciliates, flagellates, amoebae and small metazoa) was analysed for calculating SBI and SI. Floc and filamentous bacteria were examined and described accordingly with internationally adopted criteria. The results showed the full applicability of the studied techniques for optimizing the operation of a piggery slaughterhouse wastewater treatment plant. PMID:27072565

  7. Activated sludge optimization using ATP in pulp and paper industry.

    PubMed

    Bäckman, Göran; Gytel, Ulla

    2015-01-01

    The activated sludge process is an old technology, but still the most commonly used one for treatment of wastewater. Despite the wide spread usage the technology still suffers from instability (Tandoi et al. 2006) and high operating cost. Activated sludge processes often carry a large solids inventory. Managing the total inventory without interference is the key component of the optimization process described in this paper. Use of nutrients is common in pulp and paper effluent treatment. Feeding enough nutrients to support the biomass growth is a delicate balance. Overfeeding or underfeeding of nutrients can result in higher costs. Detrimental substances and toxic components in effluents entering a biological treatment system can cause severe, long lasting disturbances (Hynninen & Ingman 1998; Bergeron & Pelletier 2004). A LumiKem test kit is used to measure biological activity with adenosine triphosphate (ATP) in a pulp and paper mill. ATP data are integrated with other standardized mill parameters. Measurements of active volatile suspended solids based on ATP can be used to quantify the living biomass in the activated sludge process and to ensure that sufficient biomass is present in order to degrade the wastewater constituents entering the process. Information about active biomass will assist in optimizing sludge inventories and feeding of nutrients allowing the living biomass to re-populate to create optimal efficiency. ATP measurements can also be used to alert operators if any components toxic to bacteria are present in wastewater. The bio stress index represents the stress level experienced by the microbiological population. This parameter is very useful in monitoring toxicity in and around bioreactors. Results from the wastewater process optimization and ATP measurements showed that treatment cost could be reduced by approximately 20-30% with fewer disturbances and sustained biological activity compared to the reference period. This was mainly achieved by

  8. Model predictive control of two-step nitrification and its validation via short-cut nitrification tests.

    PubMed

    Sui, Jun; Luo, Fan; Li, Jie

    2016-10-01

    Short-cut nitrification (SCN) is shown to be an attractive technology due to its savings in aeration and external carbon source addition cost. However, the shortage of excluding nitrite nitrogen as a model state in an Activated Sludge Model limits the model predictive control of biological nitrogen removal via SCN. In this paper, a two-step kinetic model was developed based on the introduction of pH and temperature as process controller, and it was implemented in an SBR reactor. The simulation results for optimizing operating conditions showed that with increasing of dissolved oxygen (DO) the rate of ammonia oxidation and nitrite accumulation firstly increased in order to achieve a SCN process. By further increasing DO, the SCN process can be transformed into a complete nitrification process. In addition, within a certain range, increasing sludge retention time and aeration time are beneficial to the accumulation of nitrite. The implementation results in the SBR reactor showed that the data predicted by the kinetic model are in agreement with the data obtained, which indicate that the two-step kinetic model is appropriate to simulate the ammonia removal and nitrite production kinetics. PMID:26901147

  9. Evaluation-of soil enzyme activities as soil quality indicators in sludge-amended soils.

    PubMed

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

    2015-07-01

    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. PMID:26364470

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

    EPA Science Inventory

    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. Method for Adenosine 5′-Triphosphate Measurement on Coke Waste Activated Sludge

    PubMed Central

    Russell, James; Gauthier, Joseph J.

    1978-01-01

    Measurement of adenosine 5′-triphosphate (ATP) in coke waste activated sludge can provide a simple method for estimating the levels of viable microbes in the sludge. However, the presence of inhibitors such as phenol in the sludge interferes when the luciferin-luciferase method is used to measure ATP. These inhibiting substances can be removed from the sludge before extraction of ATP by washing the cells with dilute sodium dodecyl sulfate. PMID:16345281

  12. Proteomics reliability for micropollutants degradation insight into activated sludge systems.

    PubMed

    Buttiglieri, Gianluigi; Collado, Neus; Casas, Nuria; Comas, Joaquim; Rodriguez-Roda, Ignasi

    2015-01-01

    Little information is available on pharmaceutical trace compounds degradation pathways in wastewater. The potential of the proteomics approach has been evaluated to extract information on activated sludge microbial metabolism in degrading a trace concentration of a pharmaceutical compound (ibuprofen). Ibuprofen is one of the most consumed pharmaceuticals, measured in wastewater at very high concentrations and, despite its high removal rates, found in different environmental compartments. Aerated and completely mixed activated sludge batch tests were spiked with ibuprofen at 10 and 1,000 μg L(-1). Ibuprofen concentrations were determined in the liquid phase: 100% removal was observed and the kinetics were estimated. The solid phase was sampled for proteomics purposes. The first objective was to apply proteomics to evaluate protein profile variations in a complex matrix such as activated sludge. The second objective was to determine, at different ibuprofen concentrations, which proteins followed pre-defined trends. No newly expressed proteins were found. Nonetheless, the obtained results suggest that proteomics itself is a promising methodology to be applied in this field. Statistical and comparative studies analyses provided, in fact, useful information on biological reproducibility and permitted us to detect 62 proteins following coherent and plausible expected trends in terms of presence and intensity change. PMID:26360747

  13. Micropollutant degradation via extracted native enzymes from activated sludge.

    PubMed

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

    2016-05-15

    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

  14. Preparation of activated carbon from wet sludge by electrochemical-NaClO activation.

    PubMed

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

    2014-01-01

    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. PMID:25176302

  15. Substrate consumption and excess sludge reduction of activated sludge in the presence of uncouplers: a modeling approach.

    PubMed

    Xie, Wen-Ming; Ni, Bing-Jie; Sheng, Guo-Ping; Yu, Han-Qing; Yang, Min

    2010-02-01

    A mathematical model with a consideration of energy spilling is developed to describe the activated sludge in the presence of different levels of metabolic uncouplers. The consumption of substrate and oxygen via energy spilling process is modeled with a Monod term, which is dependent on substrate and inhibitor. The sensitivity of the developed model is analyzed. Three parameters, maximum specific growth rate (micro(max)), energy spilling coefficient (q(max)), and sludge yield coefficient (Y(H)) are estimated with experimental data of different studies. The values of micro(max), q(max), and Y(H) are found to be 6.72 day(-1), 5.52 day(-1), and 0.60 mg COD mg(-1) COD for 2, 4-dinitrophenol and 7.20 day(-1), 1.58 day(-1), and 0.62 mg COD mg(-1) COD for 2, 4-dichlorophenol. Substrate degradation and sludge yield could be predicted with this model. The activated sludge process in the presence of uncouplers that is described more reasonably by the new model with a consideration of energy spilling. The effects of uncouplers on substrate consumption inhibition and excess sludge reduction in activated sludge are quantified with this model. PMID:19898844

  16. Investigating the fate of activated sludge extracellular proteins in sludge digestion using sodium dodecyl sulfate polyacrylamide gel electrophoresis.

    PubMed

    Park, Chul; Helm, Richard F; Novak, John T

    2008-12-01

    The fate of activated sludge extracellular proteins in sludge digestion was investigated using three different cation-associated extraction methods and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Extraction methods used were the cation exchange resin (CER) method for extracting calcium (Ca2+) and magnesium (Mg2+), sulfide extraction for removing iron, and base treatment (pH 10.5) for dissolving aluminum. Extracellular polymeric substances extracted were then subjected to SDS-PAGE, and the resultant protein profiles were examined before and after sludge digestion. The SDS-PAGE results showed that three methods led to different SDS-PAGE profiles for both undigested and digested sludges. The results further revealed that CER-extracted proteins remained mainly undegraded in anaerobic digestion, but were degraded in aerobic digestion. While the fate of sulfide- and base-extracted proteins was not clear for aerobic digestion, their changes in anaerobic digestion were elucidated. Most sulfide-extracted proteins were removed by anaerobic digestion, while the increase in protein band intensity and diversity was observed for base-extracted proteins. These results suggest that activated sludge flocs contain different fractions of proteins that are distinguishable by their association with certain cations and that each fraction undergoes different fates in anaerobic and aerobic digestion. The proteins that were resistant to degradation and generated during anaerobic digestion were identified by liquid chromatography tandem mass spectrometry. Protein identification results and their putative roles in activated sludge and anaerobic digestion are discussed in this study. PMID:19146099

  17. Effects of total solids content on waste activated sludge thermophilic anaerobic digestion and its sludge dewaterability.

    PubMed

    Wang, Tianfeng; Chen, Jie; Shen, Honglang; An, Dong

    2016-10-01

    The role of total solids content on sludge thermophilic anaerobic digestion was investigated in batch reactors. A range of total solids content from 2% to 10% was evaluated with two replicates. The lowest inhibitory concentration for free ammonia and total ammonia of sludge thermophilic anaerobic digestion was 110.9-171.4mg/L and 1313.1-1806.7mg/L, respectively. The volumetric biogas production rate increased with increasing of total solids content, but the corresponding biogas yield per gram volatile solid decreased. The result of normalized capillary suction time indicated that the dewaterability of digested sludge at high total solids content was poor, while solid content of sediment obtained by centrifuging sludge at 2000g for 10min increased with increasing of total solids content of sludge. The results suggest that thickened sludge mixed with dewatered sludge at an appropriate ratio could get high organic loading rate, high biogas yield and adequate dewatering effort. PMID:26897469

  18. Enhancement of As(V) adsorption onto activated sludge by methylation treatment.

    PubMed

    Kang, So-Young; Kim, Dong-Wook; Kim, Kyoung-Woong

    2007-08-01

    Biosorption properties of arsenate [As(V)] onto activated sludge were investigated in batch systems. The adsorption of As(V) onto sludge increased from 23 to 266 microg/g dry weight through the methylation of the activated sludge. This increase resulted from neutralization of carboxylic groups via the methylation process. The pH effect of As(V) uptake was also investigated and As(V) adsorption by methylated sludge decreased significantly at high pH (pH > 11) due to competition between As(V) and OH(-) ions for binding sites distributed on sludge surfaces. In contrast, low pH favored As(V) adsorption by methylated sludge because of the elevated quantities of positively charged functional groups. The results suggest that methylated activated sludge may provide promising applications for the simultaneous removal and separation of As(V) from aqueous effluents. PMID:17505894

  19. Effect of dissolved organic material and cations on freeze-thaw conditioning of activated and alum sludges.

    PubMed

    Ormeci, B; Vesilind, P A

    2001-12-01

    Freeze-thaw conditioning effectively dewaters alum and activated sludges, but it works better on alum sludge than it does on activated sludge. The main difference between alum sludge and activated sludge is that activated sludge has high concentrations of both dissolved organic material and ions. Dissolved organic material and ions may possibly alter the freezing process and decrease the effectiveness of freeze-thaw conditioning on activated sludge. The objective of this study is to investigate the effect of dissolved organic material and cations on freeze-thaw conditioning of sludges, and to improve the effectiveness of freeze-thaw conditioning on activated sludge. The results of this study show that although protein, carbohydrate and cation concentrations in activated sludge supernatant are initially high, they dramatically increase after freeze-thaw conditioning. The increase is likely to come from the release of extracellular and intracellular material to sludge supernatant. The observed increase in the DNA concentration in activated sludge supernatant after freeze-thaw conditioning indicates that freeze-thaw causes cell disruption. Alum sludge supernatant, on the other hand, initially contains low concentrations of proteins, carbohydrates and cations which do not noticeably change after freeze-thaw conditioning. When ECPs (extracellular polymers) and cations are extracted from activated sludge before freeze-thaw conditioning. the sludge settles and dewaters better after the freeze-thaw. The resulting aggregates are smaller and denser resembling the "coffee ground" aggregates of alum sludge. PMID:11763031

  20. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    PubMed Central

    Linchangco, Richard

    2014-01-01

    Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH)–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus) known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1) was examined for its ability to perform heterotrophic nitrification in the presence of Cu2+ and Ni2+ and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1 mM Cu2+ or 0.5 mM Ni2+ was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1 mM Cu2+ or 0.5 mM Ni2+. The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed. PMID:25580463

  1. An activated sludge model based on activated sludge model number 3 for full-scale wastewater treatment plant simulation.

    PubMed

    Fan, Ji; Lu, Shu-Guang; Qiu, Zhao-fu; Wang, Xiao-Xia; Li, Wen-Zhen

    2009-06-01

    A modified model based on the activated sludge model no. 3 was established to simulate a full-scale municipal wastewater treatment plant in Shanghai, China. The activated sludge model no. 3 was modified to describe the simultaneous storage and growth processes occurring in activated sludge systems under aerobic and anoxic conditions. The mechanism of soluble microbial product formation and degradation by microorganisms was considered in this proposed model. Three months simulation was conducted including soluble chemical oxygen demand, NH4(+)-N, NO(X)(-)-N and T-N parameters, and compared with measured data from the Quyang wastewater treatment plant. Results indicated that the calculated effluent chemical oxygen demand and NH4(+)-N using this proposed model were in good agreement with the measured data. Results also showed that besides inert soluble organic matter contributing to the effluent chemical oxygen demand, soluble microbial products played an important part in the effluent chemical oxygen demand and, therefore, demonstrated that these products composed an important portion of effluent soluble chemical oxygen demand in wastewater treatment plants and should not be neglected. PMID:19705601

  2. Enhanced dewaterability of waste activated sludge by Fe(II)-activated peroxymonosulfate oxidation.

    PubMed

    Liu, Jun; Yang, Qi; Wang, Dongbo; Li, Xiaoming; Zhong, Yu; Li, Xin; Deng, Yongchao; Wang, Liqun; Yi, Kaixin; Zeng, Guangming

    2016-04-01

    The effect of Fe(II)-activated peroxymonosulfate (Fe(II)-PMS) oxidation on the waste activated sludge (WAS) dewatering and its mechanisms were investigated in this study. The capillary suction time (CST), specific resistance to filterability (SRF) of sludge and water content (WC) of dewatered sludge cake were chosen as the main parameters to evaluate the sludge dewaterability. Experimental results showed that Fe(II)-PMS effectively disintegrated sludge and improved sludge dewaterability. High CST and SRF reduction (90% and 97%) was achieved at the optimal conditions of PMS (HSO5(-)) 0.9mmol/gVSS, Fe(II) 0.81mmol/gVSS, and pH 6.8. Extracellular polymeric substances (EPS) and three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy before and after Fe(II)-PMS oxidation were determined to explain the enhanced dewatering mechanism. The release of EPS-bound water induced by the destruction of EPS was the primary reason for the improvement of sludge dewaterability during Fe(II)-PMS oxidation. PMID:26851897

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

    PubMed

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

    2007-03-01

    The properties of sludges from a pilot-scale submerged membrane bioreactor (SMBR) and two bench-scale complete-mix, activated sludge (CMAS) reactors treating municipal primary effluent were determined. Compared with the CMAS sludges, the SMBR sludge contained a higher amount of soluble microbial products (SMP) and colloidal material attributed to the use of a membrane for solid-liquid separation; a higher amount nocardioform bacteria, resulting from efficient foam trapping; and a lower amount of extracellular polymeric substances (EPS), possibly because there was no selective pressure for the sludge to settle. High aeration rates in both the CMAS and SMBR reactors produced sludges with higher numbers of smaller particles. Normalized capillary suction time values for the SMBR sludge were lower than for the CMAS sludges, possibly because of its lower EPS content. PMID:17469664

  4. Effect of recycling thermophilic sludge on the activated-sludge process. Report for October 1984-June 1989

    SciTech Connect

    Prakasam, T.B.S.; Soszynski, S.; Zenz, D.R.; Lue-Hing, C.; Blyth, L.

    1990-01-01

    A full-scale investigation was undertaken at Chicago's Hanover Park Water Reclamation Plant (WRP) to study whether the net sludge production from the WRP could be reduced by implementing a scheme developed by W. Torpey et al. (1984). In this process, sludge is withdrawn from a thermophilic digester operated in series with a mesophilic digester and partially recycled into the aeration tanks of the activated sludge system. The Hanover Park WRP, which has a design flow capacity of 45,420 million cu m per day (12 mgd), was split into a control section and an experimental section. The two sections were operated similarly except the thermophilic drawoff was recycled into the aeration tanks of the experimental section from a digester system consisting of mesophilic and thermophilic digesters operated in series. A reduction in net sludge production of about 10 percent was achieved at 40 percent recycle of thermophilic sludge into the aeration tanks at the Hanover Park WRP. This was a much smaller reduction than obtained by Torpey et al. Sludge dewatering properties were not improved. The recycling produced no adverse effects on quality of the treated wastewater.

  5. Cocurrent biological nitrification and denitrification in wastewater treatment

    SciTech Connect

    Spector, M.

    1998-11-01

    Repetitive conditioning of recycle activated sludge (RAS) under strict anaerobic conditions gradually changes the products of ammonia oxidation from nitrite and nitrate to nitrous oxide (N{sub 2}O) and nitrogen (N{sub 2}). Nitrite inhibits oxygen respiration of anaerobically conditioned sludge; biochemical oxygen demand (BOD) is then oxidized by nitrite, which is reduce to N{sub 2}O and N{sub 2}. When anaerobic RAS conditioning is initially imposed on a nitrifying system, Nitrobacter species continue to oxidize nitrite to nitrate and thus reduce the nitrite available to oxidize BOD. However, Nitrobacter in the mixed liquor gradually tend to wash out because the sole source of Nictrobacter energy, the oxidation of nitrite to nitrate, is diminished to the extent that nitrite is reduced. Incorporation of an RAS conditioning zone to the activate-sludge process results in evolution of a nonfilamentous biomass, which affects both cocurrent biological nitrification and denitrification (CBND) and biological phosphorus removal (BPR). The initial feed zone may be either aerobic or anaerobic. A final anoxic denitrification zone is desirable for removal of residual nitrite plus nitrate (NO{sub x}) from aeration effluent. Nitrous oxide, the main reaction product of CBND, promotes both global warming and destruction of the stratospheric ozone layer.

  6. Detection of nitrifiers and evaluation of partial nitrification for wastewater treatment: A review.

    PubMed

    Ge, Shijian; Wang, Shanyun; Yang, Xiong; Qiu, Shuang; Li, Baikun; Peng, Yongzhen

    2015-12-01

    Partial nitrification has gained broad interests in the biological nitrogen removal (BNR) from wastewater, since it alleviates carbon limitation issues and acts as a shortcut nitrogen removal system combined with anaerobic ammonium oxidation (Anammox) process. The occurrence and maintenance of partial nitrification relies on various conditions, which favor ammonium oxidizing bacteria (AOB) but inhibit or limit nitrite oxidizing bacteria (NOB). The studies of the AOB and NOB activities have been conducted by state-of-the-art molecular techniques, such as Polymerase Chain Reaction (PCR), Quantitative PCR, denaturing gradient gel electrophoresis (DGGE), Fluorescence in situ hybridization (FISH) technique, Terminal Restriction Fragment Length Polymorphism (T-RFLP), Live/Dead BacLight, and quinone profile. Furthermore, control strategies for obtaining partial nitrification are mainly focused on the pH, temperature, dissolved oxygen concentration, real-time aeration control, sludge retention time, substrate concentration, alternating anoxic and aerobic operation, inhibitor and ultrasonic treatment. Existing problems and further perspectives for the scale-up of partial nitrification are also proposed and suggested. PMID:25796420

  7. Influence of operating conditions on nitrous oxide formation during nitritation and nitrification.

    PubMed

    Schneider, Y; Beier, M; Rosenwinkel, K-H

    2014-10-01

    Nitrous oxide (N2O), a strong greenhouse gas, can be produced by ammonium-oxidizing bacteria (AOB) as a by-product of ammonium oxidation and can potentially be formed in all types of nitrification processes. However, partial nitritation has been reported to cause significantly higher N2O emissions than complete nitrification. In the study presented here, the mechanisms and factors that drive N2O formation by AOB were investigated with respect to different operational strategies to achieve nitrite accumulation base on combined evaluation of oxygen uptake rate (OUR) and N2O formation rate. On the one hand, N2O formation during partial nitritation and nitrification in a continuously stirred tank reactor (CSTR) with continuous aerobic conditions was observed. On the other hand, the effect of intermittent aeration on N2O formation during nitrification was investigated. The presence of nitrite, the extend of sludge-specific ammonium loading, low oxygen concentration, and transition from aerobic to anoxic conditions significantly increased N2O formation in this reactor independently from each other, indicating that different formation pathways, supposedly via nitrite or hydroxylamine, were active. PMID:24928380

  8. The presence and role of bacterial quorum sensing in activated sludge

    PubMed Central

    Chong, Grace; Kimyon, Onder; Rice, Scott A.; Kjelleberg, Staffan; Manefield, Mike

    2012-01-01

    Summary Activated sludge used for wastewater treatment globally is composed of a high‐density microbial community of great biotechnological significance. In this study the presence and purpose of quorum sensing via N‐acylated‐l‐homoserine lactones (AHLs) in activated sludge was explored. The presence of N‐heptanoyl‐l‐homoserine lactone in organic extracts of sludge was demonstrated along with activation of a LuxR‐based AHL monitor strain deployed in sludge, indicating AHL‐mediated gene expression is active in sludge flocculates but not in the bulk aqueous phase. Bacterial isolates from activated sludge were screened for AHL production and expression of phenotypes commonly but not exclusively regulated by AHL‐mediated gene transcription. N‐acylated‐l‐homoserine lactone and exoenzyme production were frequently observed among the isolates. N‐acylated‐l‐homoserine lactone addition to sludge upregulated chitinase activity and an AHL‐ and chitinase‐producing isolate closely related to Aeromonas hydrophila was shown to respond to AHL addition with upregulation of chitinase activity. N‐acylated‐l‐homoserine lactones produced by this strain were identified and genes ahyI/R and chiA, encoding AHL production and response and chitinase activity respectively, were sequenced. These experiments provide insight into the relationship between AHL‐mediated gene expression and exoenzyme activity in activated sludge and may ultimately create opportunities to improve sludge performance. PMID:22583685

  9. [Synergistic effects of nano-sized magnetic particles and uncoupler to the characteristics of activated sludge].

    PubMed

    Gao, Li-ying; Tang, Bing; Liang, Ling-yan; Huang, Shao-song; Fu, Feng-lian; Luo, Jian-zhong

    2012-08-01

    For improving the performance and sludge settling property of an activated sludge reduction process with uncoupler, in this investigation, uncoupler and nano-sized magnetic particles were added simultaneously to a sequencing batch reactor for exploring their synergistic effects to the characteristics of activated sludge. The results showed that the volume reduction of sludge reached 41% with single 2,4,5-Trichlorophenol (TCP) Comparing with the control experiment, the biodegradability and settling properties of the activated sludge decreased. Under the actions of TCP combined with nano-sized magnetic particles, the volume reduction of sludge reached 34%, the removal efficiencies of COD, nitrogen, and phosphorus as well as the sludge settling property were not significantly influenced. After 31 d's operation, the dehydrogenase activity was improved by 10%-18% and exhibited an accumulative effect over time. It was observed with an optical microscope that the species and amounts of protozoon and metazoan increased and a compact structure of sludge floc was formed. The results also indicated that using nano-sized magnetic particles and uncoupler could restrict the yield of excess sludge and improve the performance of an activated sludge system. PMID:23213903

  10. Variations of respiratory activity and glutathione in activated sludges exposed to low ozone doses.

    PubMed

    Dziurla, M A; Salhi, M; Leroy, P; Paul, E; Ginestet, Ph; Block, J C

    2005-07-01

    Ozonation is one of the most effective treatments for reducing the production of activated sludges in wastewater treatment plants. However, because microorganisms are present in the form of microcolonies, some bacteria may be exposed to sub-lethal ozone doses that could lead to adaptation and resistance to further exposition to oxidative treatment. This represents a major question as it may limit the effect of the treatment, especially when low ozone doses are applied. The critical ozone dosage, defined as the lowest specific transferred ozone concentration leading to a decrease in the maximum oxygen uptake rate was estimated to range between 0.9 and 13.6mg O(3)g(-1) COD(sludges), according to the sludges tested. The lowest ozone dosage leading to the decrease of GSH and GSHt concentrations could be estimated to be lower than 10mg O(3)g(-1) COD(sludges) for GSH, and close to 10mg O(3)g(-1) COD(sludges) for GSHt. After sludge exposure to low ozone doses, no higher amounts of glutathione were synthesized, suggesting that no development of resistance to ozonation occurred after sludge treatment with low ozone doses. PMID:15972223

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

    PubMed

    Ge, Huoqing; Batstone, Damien; Keller, Jurg

    2016-01-01

    The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity. PMID:26942526

  12. Trade-off between carbon emission and effluent quality of activated sludge processes under seasonal variations of wastewater temperature and mean cell retention time.

    PubMed

    Guo, Jingbo; Fu, Xin; Andrés Baquero, G; Sobhani, Reza; Nolasco, Daniel A; Rosso, Diego

    2016-03-15

    Over the seasonal cycles, the mean cell retention time (MCRT) of the activated sludge process is varied to compensate the wastewater temperature variations. The effects of these variations on the carbon footprint (CFP) and effluent quality index (EQI) of a conventional activated sludge (CAS) process and a nitrification/denitrification (NDN) process were quantified. The carbon emission included both biogenic and non-biogenic carbon. Carbon emissions of wasted biosolids management were also addressed. Our results confirmed that the effluent quality indicated by EQI was not necessarily improved by increasing MCRT. Higher MCRT increased the carbon emission and reduced excess sludge production, which decreased the potential for biogas energy recovery. The NDN process was preferable to the CAS process from the perspective of effluent quality. This consideration extended to the whole plant CFP if the N2O emitted during NDN was limited ([N2O]<1% [NH4(+)]removed) as the carbon emission per unit effluent quality achieved by NDN process is less than that of the CAS process. By putting forward carbon emission intensity (γ) derived from CFP and EQI, our work provides a quantitative tool for decision makers evaluating process alternatives when there is a trade-off between carbon emission and effluent quality. PMID:26789371

  13. Pharmaceutically active compounds in sludge stabilization treatments: anaerobic and aerobic digestion, wastewater stabilization ponds and composting.

    PubMed

    Martín, Julia; Santos, Juan Luis; Aparicio, Irene; Alonso, Esteban

    2015-01-15

    Sewage sludge disposal onto lands has been stabilized previously but still many pollutants are not efficiently removed. Special interest has been focused on pharmaceutical compounds due to their potential ecotoxicological effects. Nowadays, there is scarce information about their occurrence in different sludge stabilization treatments. In this work, the occurrence of twenty-two pharmaceutically active compounds has been studied in sludge from four sludge stabilization treatments: anaerobic digestion, aerobic digestion, composting and lagooning. The types of sludge evaluated were primary, secondary, anaerobically-digested and dehydrated, composted, mixed, aerobically-digested and dehydrated and lagoon sludge. Nineteen of the twenty-two pharmaceutically active compounds monitored were detected in sewage sludge. The most contaminated samples were primary sludge, secondary sludge and mixed sludge (the average concentrations of studied compounds in these sludges were 179, 310 and 142 μg/kg dm, respectively) while the mean concentrations found in the other types of sewage sludge were 70 μg/kg dm (aerobically-digested sludge), 63 μg/kg dm (lagoon sludge), 12 μg/kg dm (composted sludge) and 8 μg/kg dm (anaerobically-digested sludge). The antibiotics ciprofloxacin and norfloxacin were found at the highest concentration levels in most of the analyzed sludge samples (up to 2660 and 4328 μg/kg dm, respectively). Anaerobic-digestion treatment reduced more considerably the concentration of most of the studied compounds than aerobic-digestion (especially in the case of bezafibrate and fluoroquinolones) and more than anaerobic stabilization ponds (in the case of acetaminophen, atenolol, bezafibrate, carbamazepine, 17α-ethinylestradiol, naproxen and salicylic acid). Ecotoxicological risk assessment, of sludge application onto soils, has also been evaluated. Risk quotients, expressed as the ratio between the predicted environmental concentration and the predicted non

  14. EFFECT OF RECYCLING THERMOPHILICALLY DIGESTED SLUDGE ON THE ACTIVATED SLUDGE PROCESS

    EPA Science Inventory

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

  15. Diversity and dynamics of Archaea in an activated sludge wastewater treatment plant

    PubMed Central

    2012-01-01

    Background The activated sludge process is one of the most widely used methods for treatment of wastewater and the microbial community composition in the sludge is important for the process operation. While the bacterial communities have been characterized in various activated sludge systems little is known about archaeal communities in activated sludge. The diversity and dynamics of the Archaea community in a full-scale activated sludge wastewater treatment plant were investigated by fluorescence in situ hybridization, terminal restriction fragment length polymorphism analysis and cloning and sequencing of 16S rRNA genes. Results The Archaea community was dominated by Methanosaeta-like species. During a 15 month period major changes in the community composition were only observed twice despite seasonal variations in environmental and operating conditions. Water temperature appeared to be the process parameter that affected the community composition the most. Several terminal restriction fragments also showed strong correlations with sludge properties and effluent water properties. The Archaea were estimated to make up 1.6% of total cell numbers in the activated sludge and were present both as single cells and colonies of varying sizes. Conclusions The results presented here show that Archaea can constitute a constant and integral part of the activated sludge and that it can therefore be useful to include Archaea in future studies of microbial communities in activated sludge. PMID:22784022

  16. Effect of heavy metals on nitrification activity as measured by RNA- and DNA-based function-specific assays

    EPA Science Inventory

    Heavy metals can inhibit nitrification, a key process for nitrogen removal in wastewater treatment. The transcriptional responses of functional genes (amoA, hao, nirK and norB) were measured in conjunction with specific oxygen uptake rate (sOUR) for nitrifying enrichment cultures...

  17. Bifurcation and chaotic in a model for activated sludge reactors

    NASA Astrophysics Data System (ADS)

    El-Marouf, S. A. A.; Bahaa, G. M.

    2015-04-01

    A dynamical model of an activated sludge process system is considered and analyzed. Numerical techniques are used to show when the system exhibits chaos. Three choices of bifurcation parameters produce different pictures of solution behavior in the form of limit cycles, two-torus and chaotic behavior. For some range of the reactor residence time the model exhibits chaotic behavior as well. Practical criteria are also derived for the effects of feed conditions and purge fraction on the dynamic characteristics of the bioreactor model.

  18. Physicochemical changes effected in activated sludge by the earthworm Eisenia foetida. [Concentration of heavy metals during sludge catabolism

    SciTech Connect

    Hartenstein, R.; Hartenstein, F.

    1981-09-01

    Measurements were made of some physicochemical changes effected in activated sludge by the earthworm Eisenia foetida following conversion of the sludge into wormcasts. Mineralization was accelerated 1.3-fold and 2% of the minerals were assimilated. The rate at which heavy metals were concentrated during sludge catabolism was also accelerated. Castings stabilized within 2 weeks, as indexed by respirometry. Nucleic acids, which can be used as an index of microbial biomass, were present at a greater concentration in the wormcasts than in the sludge, while the phenolic content, which may potentially serve as an index of humification, was less concentrated. Other changes included a reduction in pH and an increase in oxidation-reduction potential and cation exchange capacity. The major general effect of E. foetida on the physicochemical properties of activated sludge is to convert a material which has a relatively small surface/volume ratio into numerous particles with an overall large S/V ratio, thus accelerating decomposition, mineralization, drying, and preclusion of malodor.

  19. Gamma irradiation induced disintegration of waste activated sludge for biological hydrogen production

    NASA Astrophysics Data System (ADS)

    Yin, Yanan; Wang, Jianlong

    2016-04-01

    In this paper, gamma irradiation was applied for the disintegration and dissolution of waste activated sludge produced during the biological wastewater treatment, and the solubilized sludge was used as substrate for bio-hydrogen production. The experimental results showed that the solubilization of waste activated sludge was 53.7% at 20 kGy and pH=12, and the SCOD, polysaccharides, protein, TN and TP contents in the irradiated sludge solutions was 3789.6 mg/L, 268.3 mg/L, 1881.5 mg/L, 132.3 mg/L and 80.4 mg/L, respectively. The irradiated sludge was used for fermentative hydrogen production, and the hydrogen yield was 10.5±0.7 mL/g SCODconsumed. It can be concluded that the irradiated waste activated sludge could be used as a low-cost substrate for fermentative hydrogen production.

  20. [Influence of the Application of Activated Persulfate on Municipal Sludge Conditioning].

    PubMed

    Xu, Xin; Pu, Wen-hong; Shi, Ya-fei; Yu, Wen-bo; Zhang, Shi-nan; Song, Jian; Zhang, Hao; He, Shu; Yang, Chang-zhu; Yang, Jia-kuan

    2015-11-01

    The water content of dewatered sewage sludge can decrease at about 80% by traditional sludge dewatering technologies. High water content has negative impacts on the sequent sludge disposal with a stricter standard. The sulfate free radical SO4(*-), generated by activated persulfate, is a powerful oxidant. This article found that it could improve sludge dewatering properties by using the Fe2+ activated sodium persulfate (SPS). The results showed that when using Fe2+ 25.88 mg x g(-1) (based on dry sludge solid) and S2 O8(2-) 80 mg x g(-1) (the mole ratio of Fe2+ to S2 O8(2-) was 1.1 : 1) for sludge conditioning, it could reduce the capillary suction time (CST) and specific resistance to filtration (RSF) of sludge, increased the protein and ploysaccharide as well as the COD concentration in the filtrate. The further research showed that this method could change the zeta potential of sludge, increased the sludge particle specific surface area, and made flocs become a loose layered structure from dense clusters, which was beneficial to improve the sludge dewaterability. PMID:26911010

  1. Suppression of soil nitrification by plants.

    PubMed

    Subbarao, Guntur Venkata; Yoshihashi, Tadashi; Worthington, Margaret; Nakahara, Kazuhiko; Ando, Yasuo; Sahrawat, Kanwar Lal; Rao, Idupulapati Madhusudhana; Lata, Jean-Christophe; Kishii, Masahiro; Braun, Hans-Joachim

    2015-04-01

    Nitrification, the biological oxidation of ammonium to nitrate, weakens the soil's ability to retain N and facilitates N-losses from production agriculture through nitrate-leaching and denitrification. This process has a profound influence on what form of mineral-N is absorbed, used by plants, and retained in the soil, or lost to the environment, which in turn affects N-cycling, N-use efficiency (NUE) and ecosystem health and services. As reactive-N is often the most limiting in natural ecosystems, plants have acquired a range of mechanisms that suppress soil-nitrifier activity to limit N-losses via N-leaching and denitrification. Plants' ability to produce and release nitrification inhibitors from roots and suppress soil-nitrifier activity is termed 'biological nitrification inhibition' (BNI). With recent developments in methodology for in-situ measurement of nitrification inhibition, it is now possible to characterize BNI function in plants. This review assesses the current status of our understanding of the production and release of biological nitrification inhibitors (BNIs) and their potential in improving NUE in agriculture. A suite of genetic, soil and environmental factors regulate BNI activity in plants. BNI-function can be genetically exploited to improve the BNI-capacity of major food- and feed-crops to develop next-generation production systems with reduced nitrification and N2O emission rates to benefit both agriculture and the environment. The feasibility of such an approach is discussed based on the progresses made. PMID:25711823

  2. Purification of total DNA extracted from activated sludge.

    PubMed

    Shan, Guobin; Jin, Wenbiao; Lam, Edward K H; Xing, Xinhui

    2008-01-01

    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 (total 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. PMID:18572527

  3. Grazing by protozoa as selection factor for activated sludge bacteria.

    PubMed

    Güde, H

    1979-09-01

    In continuous culture enrichments that were inoculated with activated sludge and were fed with polymeric substrates, freely dispersed single-celled bacteria belonging to theCytophaga group dominated among the initial populations, irrespective of the activated sludge source. These populations were grazed by flagellated protozoa which after several days reached high cell densities. Other morphologic bacterial groups such as spiral-shaped or filamentous bacteria then became dominant. In defined mixed culture experiments with bacterial isolates from the enrichment cultures, it was shown that a "grazing-resistant"Microcyclus strain outgrew aCytophaga strain in the presence of grazing protozoa. In contrast, theCytophaga strain competed successfully with theMicrocyclus strain and with other "grazing-resistant" strains under protozoa-free conditions. Furthermore, it was demonstrated that assumed grazing resistance factors such as floccing or filamentous growth were lost by some of the strains when they were grown for several generations in continuous culture under the same conditions, but in the absence of protozoa. PMID:24232496

  4. Pyrolysis of activated sludge: energy analysis and its technical feasibility.

    PubMed

    Agarwal, Manu; Tardio, James; Venkata Mohan, S

    2015-02-01

    A comprehensive study on the potential of pyrolysis of activated sludge to generate substances that can be used to produce energy was evaluated for its technical and environmental viability. The products of the process viz., pyrolysis gas, pyrolysis oil and char can readily be used by the major energy consumers viz., electricity and transportation. Based on the results obtained it is estimated that a 1 ton capacity process for pyrolysis of activated sludge can serve the electrical needs of a maximum of 239, 95 and 47 Indian houses per day, considering lower middle class, middle class and upper middle class, respectively. In addition the process would also produce the daily methane (CNG) requirement of 128 public transport buses. The process was determined to be technically feasible at low and medium temperatures for both, pyrolysis gas and electrical energy. The gas generated could be utilized as fuel directly while the oil generated would require pretreatment before its potential application. The process is potentially sustainable when commercialized and can self-sustain in continuous mode of operation in biorefinery context. PMID:25451771

  5. Effects of waste activated sludge and surfactant addition on primary sludge hydrolysis and short-chain fatty acids accumulation.

    PubMed

    Ji, Zhouying; Chen, Guanlan; Chen, Yinguang

    2010-05-01

    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. PMID:20096564

  6. Effect of low temperature on highly unsaturated fatty acid biosynthesis in activated sludge.

    PubMed

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

    2016-07-01

    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. PMID:27035483

  7. Toxic influence of silver and uranium salts on activated sludge of wastewater treatment plants and synthetic activated sludge associates modeled on its pure cultures.

    PubMed

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

    2015-01-01

    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. PMID:25027236

  8. Influence of influent wastewater communities on temporal variation of activated sludge communities.

    PubMed

    Lee, Sang-Hoon; Kang, Hyun-Jin; Park, Hee-Deung

    2015-04-15

    Continuously feeding influent wastewater containing diverse bacterial species to a wastewater treatment activated sludge bioreactor may influence the activated sludge bacterial community temporal dynamics. To explore this possibility, this study tracked influent wastewater and activated sludge bacterial communities by pyrosequencing 16S rRNA genes from four full-scale wastewater treatment plants over a 9-month period. The activated sludge communities showed significantly higher richness and evenness than the influent wastewater communities. Furthermore, the two communities were different in composition and temporal dynamics. These results demonstrate that the impact of the influent wastewater communities on the activated sludge communities was weak. Nevertheless, 4.3-9.3% of the operational taxonomic units (OTUs) detected in the activated sludge were shared with the influent wastewater, implying contribution from influent wastewater communities to some extent. However, the relative OTU abundance of the influent wastewater was not maintained in the activated sludge communities (i.e., weak neutral assembly). In addition, the variability of the communities of the shared OTUs was moderately correlated with abiotic factors imposed to the bioreactors. Taken together, temporal dynamics of activated sludge communities appear to be predominantly explained by species sorting processes in response to influent wastewater communities. PMID:25655320

  9. NITRIFICATION INHIBITION BIOKINETICS

    EPA Science Inventory

    The report gives results of studies of the causes of instability of the nitrification process as observed in steel industry wastewaters. Theoretical calculations, based on laboratory defined parameters, suggest allowable concentrations of trace inhibitors and operational strategi...

  10. An ecosystem analysis of the activated sludge microbial community.

    PubMed

    Yiannakopoulou, Trissevyene V

    2010-01-01

    This study was undertaken (i) to investigate the interactions of the activated sludge microbial community in a chemostat with the "environment", such as the substrate composition and variations, (ii) to investigate how these interactions affect the quality of the treated effluent and (iii) to determine the limits or applicability conditions to the indicators and to the prediction potential of the treated effluent quality. This work presents (a) the experimental results obtained from a reactor fed municipal wastewater (Data Set2-DS2) concerning the reactor's operating conditions and the microbial community of the sludge (b) comparisons between DS2 and an older Data Set (DS1) obtained when the reactor was fed synthetic substrate, all other experimental conditions being identical, and (c) simulation results and sensitivity analyses of two model runs (R1 and R2, corresponding to DS1 and DS2). The first trophic level (P(1)) of the DS2 microbial community consisted of bacteria, the second trophic level (P(2)) of bacteria-eating protozoa, rotifers and nematodes and the third trophic level (P(3)) of carnivorous protozoa and arthropods. Rotifers were an important constituent of the DS2 microbial community. The DS1 and DS1 communities differed in total size, trophic level sizes and species composition. Correlations between the major microbial groups of DS2 community and either loading rates or effluent quality attributes were generally low, but the correlation of bacteria with SVI and ammonia in the effluent was better. Also, the ratio of rotifers to protozoa in P(2) was correlated to BOD in the effluent. The results of this work indicate that predictions of the treated effluent quality based only on protozoa may not be safe. Sensitivity analysis of R2 run indicate that, when variation in Y and K(d) biokinetic coefficients of the sludge are combined with fluctuations in composition and quality of municipal wastewater entering the reactor, then sufficient significant

  11. Effect of petrochemical sludge concentrations of changes in mutagenic activity during soil bioremediation process.

    PubMed

    Morelli, I S; Vecchioli, G I; Del Panno, M T; Painceira, M T

    2001-10-01

    The present study was performed to assess the effect of the petrochemical sludge application rate on the mutagenic activity (Ames test) of soil and the persistence of mutagenic activity during laboratory soil bioremediation process. Sludge-soil systems were prepared at four different sludge application rates (1.25, 2.5, 5, and 10% w/w). Unamended soil was used as a control. Immediately following sludge application, in the absence or presence of S9, a linear correlation between sludge application rates and mutagenicity was found but differed significantly (p < 0.05) from the control system only at higher application rates (5 and 10% w/w). The direct mutagenicity of all systems decreases during the bioremediation process, and after a year of treatment only the 10% system induced a mutagenic response that was significantly different from the control system. On the other hand, an initial increase of the indirect mutagenicity was observed at all application rates. The time required for observing this increase was inversely proportional to the initial sludge concentration. After a year of treatment, the indirect mutagenicity of all sludge-amended soils was not significantly different but was significantly different from the unamended soils. The persistence of the direct mutagenic activity of the sludge-amended soils was related to the sludge concentration, whereas the indirect mutagenic persistence was related to the relationship between easily degradable hydrocarbons and polynuclear aromatic hydrocarbons concentration and independent from the initial application rate. PMID:11596747

  12. Thermal hydrolysis of waste activated sludge at Hengelo Wastewater Treatment Plant, the Netherlands.

    PubMed

    Oosterhuis, Mathijs; Ringoot, Davy; Hendriks, Alexander; Roeleveld, Paul

    2014-01-01

    The thermal hydrolysis process (THP) is a sludge treatment technique which affects anaerobic biodegradability, viscosity and dewaterability of waste activated sludge (WAS). In 2011 a THP-pilot plant was operated, connected to laboratory-scale digesters, at the water board Regge en Dinkel and in cooperation with Cambi A.S. and MWH Global. Thermal hydrolysis of WAS resulted in a 62% greater volatile solids (VS) reduction compared to non-hydrolysed sludge. Furthermore, the pilot digesters could be operated at a 2.3 times higher solids loading rate compared to conventional sludge digesters. By application of thermal sludge hydrolysis, the overall efficiency of the sludge treatment process can be improved. PMID:25026572

  13. Activity, life time and effect of hydrolytic enzymes for enhanced biogas production from sludge anaerobic digestion.

    PubMed

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

    2016-10-15

    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 (<24 h) in both waste activated sludge and anaerobic digester sludge environments and that this was, for the majority of 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. PMID:27498254

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

    PubMed

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

    2016-01-01

    Extensive use of nanoparticles (NPs) in consumer and industrial products has led to concerns about their potential environmental impacts; however, the influences of different NPs (e.g., nZVI (nano zero-valent iron), Ag NPs, Fe2O3 NPs and MgO NPs) on the anaerobic digestion of sludge have not yet been studied in depth. Additionally, a new guideline or the use of different NPs in the anaerobic digestion of sludge should be established to improve the anaerobic digestion of sludge and avoid inhibitory effects. This study investigated the effects of four representative NPs (i.e., nZVI, Ag NPs, Fe2O3 NPs and MgO NPs) on methane production during the anaerobic digestion of waste activated sludge (WAS). The presence of 10 mg/g total suspended solids (TSS) nZVI and 100 mg/g TSS Fe2O3 NPs increased methane production to 120% and 117% of the control, respectively, whereas 500 mg/g TSS Ag NPs and 500 mg/g TSS MgO NPs generated lower levels of methane production (73.52% and 1.08% that of the control, respectively). These results showed that low concentrations of nZVI and Fe2O3 NPs promoted the amount of microbes (Bacteria and Archaea) and activities of key enzymes but that higher concentrations of Ag NPs and MgO NPs inhibited them. PMID:27166174

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    PubMed Central

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

    2016-01-01

    Extensive use of nanoparticles (NPs) in consumer and industrial products has led to concerns about their potential environmental impacts; however, the influences of different NPs (e.g., nZVI (nano zero-valent iron), Ag NPs, Fe2O3 NPs and MgO NPs) on the anaerobic digestion of sludge have not yet been studied in depth. Additionally, a new guideline or the use of different NPs in the anaerobic digestion of sludge should be established to improve the anaerobic digestion of sludge and avoid inhibitory effects. This study investigated the effects of four representative NPs (i.e., nZVI, Ag NPs, Fe2O3 NPs and MgO NPs) on methane production during the anaerobic digestion of waste activated sludge (WAS). The presence of 10 mg/g total suspended solids (TSS) nZVI and 100 mg/g TSS Fe2O3 NPs increased methane production to 120% and 117% of the control, respectively, whereas 500 mg/g TSS Ag NPs and 500 mg/g TSS MgO NPs generated lower levels of methane production (73.52% and 1.08% that of the control, respectively). These results showed that low concentrations of nZVI and Fe2O3 NPs promoted the amount of microbes (Bacteria and Archaea) and activities of key enzymes but that higher concentrations of Ag NPs and MgO NPs inhibited them. PMID:27166174

  17. Reduction of sludge generation by the addition of support material in a cyclic activated sludge system for municipal wastewater treatment.

    PubMed

    Araujo, Moacir Messias de; Lermontov, André; Araujo, Philippe Lopes da Silva; Zaiat, Marcelo

    2013-09-01

    An innovative biomass carrier (Biobob®) was tested for municipal wastewater treatment in an activated sludge system to evaluate the pollutant removal performance and the sludge generation for different carrier volumes. The experiment was carried out in a pilot-scale cyclic activated sludge system (CASS®) built with three cylindrical tanks in a series: an anoxic selector (2.1 m(3)), an aerobic selector (2.5 m(3)) and the main aerobic reactor (25.1 m(3)). The results showed that by adding the Biobob® carrier decreased the MLVSS concentration, which consequently reduced the waste sludge production of the system. Having 7% and 18% (v/v) support material in the aerobic reactor, the observed biomass yield decreased 18% and 36%, respectively, relative to the reactor operated with suspended biomass. The addition of media did not affect the system's performance for COD and TSS removal. However, TKN and TN removal were improved by 24% and 14%, respectively, using 18% (v/v) carrier. PMID:23831747

  18. Enrichment and activity of methanotrophic microorganisms from municipal wastewater sludge.

    PubMed

    Siniscalchi, Luciene Alves Batista; Vale, Isabel Campante; Dell'Isola, Jéssica; Chernicharo, Carlos Augusto; Calabria Araujo, Juliana

    2015-01-01

    In this study, methanotrophic microorganisms were enriched from a municipal wastewater sludge taken from an Upflow Anaerobic Sludge Blanket reactor. The enrichment was performed in a sequencing batch reactor (SBR) with an autotrophic medium containing nitrite and nitrate. The microbial community composition of the inoculum and of the enrichment culture after 100 days of SBR operation was investigated and compared with the help of data obtained from 454 pyrosequencing analyses. The nitrite and nitrate removal efficiencies were 68% and 53%, respectively, probably due to heterotrophic denitrification. Archaeal cells of the anaerobic methanotrophic Archaic (ANME)-I and ANME-II groups were detected by polymerase chain reaction throughout the whole cultivation period. Pyrosequencing analysis showed that community composition was different among the two samples analysed. The dominant phyla found in the inoculum were Synergistestes, Firmicutes and Euryarchaeota, while Planctomycetes, Verrucomicrobia, Chloroflexi and Proteobacteria prevailed in the enriched biomass. The cultivation conditions decreased Methanobacterium abundance from 8% to 1%, and enriched for methanotrophic bacteria such as Methylocaldum, Methylocistis and Methylosinus. Sequences of Methylocaldum sp. accounted for 2.5% of the total reads. The presence and high predominance of Verrucomicrobia in the enriched biomass suggested that other unknown methanotrophic species related to that phylum might also have occurred in the reactor. Anaerobic methane oxidation activity was measured for both samples, and showed that the activity of the enrichment culture was nearly three times higher than the activity of the inoculum. Taken together, these results showed that the inoculum type and cultivation conditions were properly suited for methanotrophic enrichment. PMID:25495866

  19. Fenton peroxidation improves the drying performance of waste activated sludge.

    PubMed

    Dewil, Raf; Baeyens, Jan; Neyens, Elisabeth

    2005-01-31

    Advanced sludge treatment processes (AST) reduce the amount of sludge produced and improve the dewaterability, thus probably also affecting the heat transfer properties and the drying characteristics of the sludge. This paper studies the influence of the Fenton peroxidation on the thermal conductivity of the sludge. Results demonstrate that the Fenton's peroxidation positively influences the sludge cake consistency and hence enhances the mechanical dewaterability and the drying characteristics of the dewatered sludge. For the two sludges used in this study, i.e. obtained from the wastewater treatment plants (WWTP) of Tienen and Sint-Niklaas--the dry solids content of the mechanically dewatered sludge increased from 22.5% to 40.3% and from 18.7% to 35.2%, respectively. The effective thermal conductivity k(e) of the untreated and the peroxidized sludges is measured and used to determine the heat transfer coefficient h(s). An average improvement for k(e) of 16.7% (Tienen) and 5.8% (Sint-Niklaas) was observed. Consequently the value of h(s) increased with 15.6% (Tienen) and 5.0% (Sint-Niklaas). This increased heat transfer coefficient in combination with the increased dewaterability has direct implications on the design of sludge dryers. A plate-to-plate calculation of a multiple hearth dryer illustrates that the number of plates required to dry the peroxidized sludge to 90% DS is less than half the number of plates needed to dry untreated sludge. This results in reduced dryer dimensions or a higher capacity for an existing dryer of given dimensions. PMID:15629575

  20. SUMMARY REPORT: THE CAUSES AND CONTROL OF ACTIVATED SLUDGE BULKING AND FOAMING

    EPA Science Inventory

    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 ...

  1. Assessing the Nonbiodegradable Fraction of the Thickened Waste Activated Sludge.

    PubMed

    Elbeshbishy, Elsayed; Dhar, Bipro Ranjan; Nakhla, George

    2015-08-01

    In this study, the feasibility of using three methods to estimate the nonbiodegradable fraction of five thickened waste activated sludge (TWAS) samples was evaluated using long-term biochemical methane potential tests at four substrate to biomass ratios. The nonbiodegradable fraction was calculated based on the remaining volatile suspended solids (VSS), remaining total chemical oxygen demand (TCOD), and remaining total organic carbon (TOC). It was evident that the nonbiodegradable fraction of TWAS ranged from 12 to 27%. The average nonbiodegradable fractions of TWAS were 21, 18, and 23% based on remaining VSS, TCOD, and TOC, respectively. The proposed method can be potentially used to characterize biosolids for design and modeling anaerobic treatment processes. PMID:26237686

  2. [First sequencing then connecting cultivation of the organisms and fast start-up of A2N two-sludge system].

    PubMed

    Yang, Qing-juan; Wang, Shu-ying; Liu, Ying; Yuan, Zhi-guo; Ge, Chong

    2008-08-01

    Using domestic sewage, the cultivation of denitrifying phosphorus removing bacteria (DPB) and start-up of A2N two-sludge system were investigated in a laboratory. The A2N system started up fast by using the method that first bringing up DPB and nitrification biofilm separately then connecting them in the A2N system. The enrichment of DPB used activated sludge from the sedimentation tank of a wastewater treatment plant that working about phosphorus removal. In a sequencing batch reactor (SBR), the sludge mixture was operated under anaerobic-aerobic (A/O) condition firstly. Then, the activated sludge was conducted under anaerobic-anoxic (A/A) condition. During the experiment period of 32 d, DPB was successfully enriched. At the same time, utilizing the activated sludge that enriched of nitrifying bacteria, nitrification biofilm was grown up in another SBR. After 30 d, the average ammonia removal efficiency steadily stayed above 99%. Later, using the nitrification biofilm and the activated sludge that enriched of DPB, the A2 N system was connected for dealing with domestic sewage. After 11 d, the treatment effect of A2 N system attained steady. The total nitrogen and phosphorus concentration of effluent are 0, the nitrate concentration is 10.26 mg/L, and COD is 19.56 mg/L. The removal efficiency of COD, ammonia, total nitrogen and phosphorus are 91%, 100%, 77% and 100%, respectively. Each result shows that the A2N system is started up successfully. PMID:18839580

  3. SLUDGE BATCH 7B QUALIFICATION ACTIVITIES WITH SRS TANK FARM SLUDGE

    SciTech Connect

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

    2011-11-16

    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

  4. [Microbial composition of the activated sludges of the Moscow wastewater treatment plants].

    PubMed

    Kallistova, A Iu; Pimenov, N V; Kozlov, M N; Nikolaev, Iu A; Dorofeev, A G; Aseeva, V G; Grachev, V A; Men'ko, E V; Berestovskaia, Iu Iu; Nozhevnikova, A N; Kevbrina, M V

    2014-01-01

    The contribution of the major technologically important microbial groups (ammonium- and nitrite-oxidizing, phosphate-accumulating, foam-inducing, and anammox bacteria, as well as planctomycetes and methanogenic archaea) was characterized for the aeration tanks of the Moscow wastewater treatment facilities. FISH investigation revealed that aerobic sludges were eubacterial communities; the metabolically active archaea contributed insignificantly. Stage II nitrifying microorganisms and planctomycetes were significant constituents of the bacterial component of activated sludge, with Nitrobacter spp. being the dominant nitrifier. No metabolically active anammox bacteria were revealed in the sludge from aeration tanks. The sludge from the aeration tanks using different wastewater treatment technologies were found to differ in characteristics. Abundance of the nitrifying and phosphate-accumulating bacteria in the sludges generally correlated with microbial activity, in microcosms and with efficiency of nitrogen and phosphorus removal from wastewater. The highest microbial numbers and activity were found in the sludges of the tanks operating according to the technologies developed in the universities of Hanover and Cape Town. The activated sludge from the Novokur yanovo facilities, where abundant growth of filamentous bacteria resulted in foam formation, exhibited the lowest activity The group of foaming bacteria included Gordonia spp. and Acinetobacter spp., utilizing petroleum and motor oils, Sphaerotilus spp. utilizing unsaturated fatty acids, and Candidatus 'Microthrix parvicella'. Thus, the data on abundance and composition of metabolically active microorganisms obtained by FISH may be used for the technological control of wastewater treatment. PMID:25844473

  5. Novel nitrifiers and comammox in a full-scale hybrid biofilm and activated sludge reactor revealed by metagenomic approach.

    PubMed

    Chao, Yuanqing; Mao, Yanping; Yu, Ke; Zhang, Tong

    2016-09-01

    Biofilms are widely used in wastewater treatment for their particular enhancement of nitrogen removal and other significant advantages. In this study, the diversity and potential functions of nitrogen removal bacteria in suspended activated sludge (AS) and biofilm of a full-scale hybrid reactor were uncovered by metagenomes (∼34 Gb), coupled with PCR-based 454 reads (>33 K reads). The results indicated that the diversity and abundance of nitrifiers and denitrifiers in biofilm did not surpass that in AS, while more nitrification and denitrification genes were indeed found in biofilm than AS, suggesting that the increased nitrogen removal ability by applying biofilm might be attributed to the enhancement of removal efficiency, rather than the biomass accumulation of nitrogen removal bacteria. The gene annotation and phylogenetic analysis results revealed that AS and biofilm samples consisted of 6.0 % and 9.4 % of novel functional genes for nitrogen removal and 18 % and 30 % of new Nitrospira species for nitrite-oxidizing bacteria, respectively. Moreover, the identification of Nitrospira-like amoA genes provided metagenomic evidence for the presence of complete ammonia oxidizer (comammox) with the functional potential to perform the complete oxidation of ammonia to nitrate. These findings have significant implications in expanding our knowledge of the biological nitrogen transformations in wastewater treatment. PMID:27287850

  6. Nitrogen removal from wastewater and bacterial diversity in activated sludge at different COD/N ratios and dissolved oxygen concentrations.

    PubMed

    Zielińska, Magdalena; Bernat, Katarzyna; Cydzik-Kwiatkowska, Agnieszka; Sobolewska, Joanna; Wojnowska-Baryła, Irena

    2012-01-01

    The impact of the organic carbon to nitrogen ratio (chemical oxygen demand (COD)/N) in wastewater and dissolved oxygen (DO) concentration on carbon and nitrogen removal efficiency, and total bacteria and ammonia-oxidizing bacteria (AOB) communities in activated sludge in constantly aerated sequencing batch reactors (SBRs) was determined. At DO of 0.5 and 1.5 mg O2/L during the aeration phase, the efficiency of ammonia oxidation exceeded 90%, with nitrates as the main product. Nitrification and denitrification achieved under the same operating conditions suggested the simultaneous course of these processes. The most effective nitrogen elimination (above 50%) was obtained at the COD/N ratio of 6.8 and DO of 0.5 mg O2/L. Total bacterial diversity was similar in all experimental series, however, for both COD/N ratios of 6.8 and 0.7, higher values were observed at DO of 0.5 mg O2/L. The diversity and abundance of AOB were higher in the reactors with the COD/N ratio of 0.7 in comparison with the reactors with the COD/N of 6.8. For both COD/N ratios applied, the AOB population was not affected by oxygen concentration. Amplicons with sequences indicating membership of the genus Nitrosospira were the determinants of variable technological conditions. PMID:23505865

  7. Biodegradability enhancement of a leachate after biological lagooning using a solar driven photo-Fenton reaction, and further combination with an activated sludge biological process, at pre-industrial scale.

    PubMed

    Silva, Tânia F C V; Fonseca, Amélia; Saraiva, Isabel; Vilar, Vítor J P; Boaventura, Rui A R

    2013-06-15

    This work proposes an integrated leachate treatment strategy, combining a solar photo-Fenton reaction, to enhance the biodegradability of the leachate from an aerated lagoon, with an activated sludge process, under aerobic and anoxic conditions, to achieve COD target values and nitrogen content according to the legislation. The efficiency and performance of the photo-Fenton reaction, concerning a sludge removal step after acidification, defining the optimum phototreatment time to reach a biodegradable wastewater that can be further oxidized in a biological reactor and, activation sludge biological process, defining the nitrification and denitrification reaction rates, alkalinity balance and methanol dose necessary as external carbon source, was evaluated in the integrated system at a scale close to industrial. The pre-industrial plant presents a photocatalytic system with 39.52 m(2) of compound parabolic collectors (CPCs) and 2 m(3) recirculation tank and, an activated sludge biological reactor with 3 m(3) capacity. Leachate biodegradability enhancement by means of a solar driven photo-Fenton process was evaluated using direct biodegradability tests, as Zahn-Wellens method, and indirect measure according to average oxidation state (AOS), low molecular carboxylic acids content (fast biodegradable character) and humic substances (recalcitrant character) concentration. Due to high variability of leachate composition, UV absorbance on-line measurement was established as a useful parameter for photo-Fenton reaction control. PMID:23642652

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

    PubMed

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

    2016-08-01

    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. PMID:27140818

  9. Activated sludge process: Waste treatment. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    1996-01-01

    The bibliography contains citations concerning the use of the activated sludge process in waste and wastewater treatment. Topics include biochemistry of the activated sludge process, effects of various pollutants on process activity, effects of environmental variables such as oxygen and water levels, and nutrient requirements of microorganisms employed in activated sludge processes. The citations also explore use of the process to treat specific wastes, such as halocarbons, metallic wastes, and petrochemical effluents; and wastes from pharmaceutical and dairy processes. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  10. Activated sludge process: Waste treatment. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    Not Available

    1993-10-01

    The bibliography contains citations concerning the use of the activated sludge process in waste and wastewater treatment. Topics include biochemistry of the activated sludge process, effects of various pollutants on process activity, effects of environmental variables such as oxygen and water levels, and nutrient requirements of microorganisms employed in activated sludge processes. The citations also explore use of the process to treat specific wastes, such as halocarbons, metallic wastes, and petrochemical effluents; and wastes from pharmaceutical and dairy processes. (Contains 250 citations and includes a subject term index and title list.)

  11. Activated sludge process: Waste treatment. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning the use of the activated sludge process in waste and wastewater treatment. Topics include biochemistry of the activated sludge process, effects of various pollutants on process activity, effects of environmental variables such as oxygen and water levels, and nutrient requirements of microorganisms employed in activated sludge processes. The citations also explore use of the process to treat specific wastes, such as halocarbons, metallic wastes, and petrochemical effluents; and wastes from pharmaceutical and dairy processes. (Contains 250 citations and includes a subject term index and title list.)

  12. Nitrification and denitrifying phosphorus removal in an upright continuous flow reactor.

    PubMed

    Reza, Maryam; Alvarez Cuenca, Manuel

    2016-01-01

    Simultaneous nitrification and denitrifying phosphorus removal was achieved in a single-sludge continuous flow bioreactor. The upright bioreactor was aligned with a biomass fermenter (BF) and operated continuously for over 350 days. This study revealed that unknown bacteria of the Saprospiraceae class may have been responsible for the successful nutrient removal in this bioreactor. The successive anoxic-aerobic stages of the bioreactor with upright alignment along with a 60 L BF created a unique ecosystem for the growth of nitrifier, denitrifiers, phosphorus accumulating organisms and denitrifying phosphorus accumulating organisms. Furthermore, total nitrogen to chemical oxygen demand (COD) ratio and total phosphorus to COD ratio of 0.6 and 0.034, respectively, confirmed the comparative advantages of this advanced nutrient removal process relative to both sequencing batch reactors and activated sludge processes. The process yielded 95% nitrogen removal and over 90% phosphorus removal efficiencies. PMID:27148710

  13. EVALUATION OF WASTE CITRUS ACTIVATED SLUDGE IN POULTRY FEEDS

    EPA Science Inventory

    Experiments were conducted on chick broilers and hens to determine the metabolizable energy of citrus sludge. A determination of metabolizable energy values showed that the values decreased as the level of citrus sludge in the diet increased. A series of protein levels were fed t...

  14. Modelling a full scale membrane bioreactor using Activated Sludge Model No.1: challenges and solutions.

    PubMed

    Delrue, F; Choubert, J M; Stricker, A E; Spérandio, M; Mietton-Peuchot, M; Racault, Y

    2010-01-01

    A full-scale membrane bioreactor (1,600 m(3) d(-1)) was monitored for modelling purposes during the summer of 2006. A complete calibration of the ASM1 model is presented, in which the key points were the wastewater characterisation, the oxygen transfer and the biomass kinetics. Total BOD tests were not able to correctly estimate the biodegradable fraction of the wastewater. Therefore the wastewater fractionation was identified by adjusting the simulated sludge production rate to the measured value. MLVSS and MLSS were accurately predicted during both calibration and validation periods (20 and 30 days). Because the membranes were immerged in the aeration tank, the coarse bubble and fine bubble diffusion systems coexisted in the same tank. This allowed five different aeration combinations, depending whether the 2 systems were operating separately or simultaneously, and at low speed or high speed. The aeration control maintained low DO concentrations, allowing simultaneous nitrification and denitrification. This made it difficult to calibrate the oxygen transfer. The nitrogen removal kinetics were determined using maximum nitrification rate tests and an 8-hour intensive sampling campaign. Despite the challenges encountered, a calibrated set of parameters was identified for ASM1 that gave very satisfactory results for the calibration period. Matching simulated and measured data became more difficult during the validation period, mainly because the dominant aeration configuration had changed. However, the merit of this study is to be the first effort to simulate a full-scale MBR plant. PMID:21076205

  15. Activated Sludge. Selected Instructional Activities and References. Instructional Resources Monograph Series.

    ERIC Educational Resources Information Center

    Shepard, Clinton L.; Walasek, James B.

    This monograph contains a variety of selected materials related to wastewater treatment and water quality education and instruction. Part I presents a brief discussion of the activated sludge process in wastewater treatment operations. Part II, Instructional Units, contains selected portions of existing programs which may be utilized in…

  16. Effect of low dissolved oxygen on simultaneous nitrification and denitrification in a membrane bioreactor treating black water.

    PubMed

    Hocaoglu, S Murat; Insel, G; Cokgor, E Ubay; Orhon, D

    2011-03-01

    Effect of low dissolved oxygen on simultaneous nitrification and denitrification was evaluated in a membrane bioreactor treating black water. A fully aerobic membrane bioreactor was operated at a sludge age of 60 days under three low dissolved oxygen (DO) levels below 0.5mg/L. It sustained effective simultaneous nitrification/denitrification for the entire observation period. Nitrification was incomplete due to adverse effects of a number of factors such as low DO level, SMPs inhibition, alkalinity limitation, etc. DO impact was more significant on denitrification: Nitrate was fully removed at low DO level but the removal was gradually reduced as DO was increased to 0.5mg/L. Nitrogen removal remained optimal within the DO range of 0.15-0.35 mg/L. Experimental results were calibrated and simulated by model evaluation with the same model coefficients. The model defined improved mass transfer with lower affinity coefficients for oxygen and nitrate as compared to conventional activated sludge. PMID:21239168

  17. On the occurrence of anoxic microniches, denitrification, and sulfate reduction in aerated activated sludge

    SciTech Connect

    Schramm, A.; Santegoeds, C.M.; Nielsen, H.K.; Ploug, H.; Wagner, M.; Pribyl, M.; Wanner, J.; Amann, R.; De Beer, D.

    1999-09-01

    A combination of different methods was applied to investigate the occurrence of anaerobic processes in aerated activated sludge. Microsensor measurements (O{sub 2}, NO{sub 2}{sup {minus}}, NO{sub 3}{sup {minus}}, and H{sub 2}S) were performed on single sludge flocs to detect anoxic niches, nitrate reduction, or sulfate reduction on a microscale. Incubations of activated sludge with {sup 15}NO{sub 3}{sup {minus}} and {sup 35}SO{sub 4}{sup 2{minus}} were used to determine denitrification and sulfate reduction rates on a batch scale. In four of six investigated sludges, no anoxic zones developed during aeration, and consequently denitrification rates were very low. However, in two sludges anoxia in flocs coincided with significant denitrification rates. Sulfate reduction could not be detected in any sludge in either the microsensor or the batch investigation, not even under short-term anoxic conditions. In contrast, the presence of sulfate-reducing bacteria was shown by fluorescence in situ hybridization with 16S rRNA-targeted oligonucleotide probes and by PCR-based detection of genes coding for the dissimilatory sulfite reductase. A possible explanation for the absence of advection, i.e., facilitated by flow through pores and channels. This possibility is suggested by the irregularity of some oxygen profiles and by confocal laser scanning microscopy of the three-dimensional floc structures, which showed that flocs from the two sludges in which anoxic zones were found were apparently denser than flocs from the other sludges.

  18. A comparative evaluation of dried activated sludge and mixed dried activated sludge with rice husk silica to remove hydrogen sulfide

    PubMed Central

    2013-01-01

    The aim of this study was to investigate the effectiveness of dried activated sludge (DAS) and mixed dried activated sludge with rice husk silica (DAS & RHS) for removal of hydrogen sulfide (H2S). Two laboratory-scale filter columns (packed one litter) were operated. Both systems were operated under different conditions of two parameters, namely different inlet gas concentrations and different inlet flow rates. The DAS & RHS packed filter showed more than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 45 to 90 s and 300 mg/L inlet concentration of H2S. However, the RE decreased to 96.87% with the EBRT of 30 s. In the same condition, the DAS packed filter showed 99.37% RE. Nonetheless, the RE was shown to have dropped to 82.09% with the EBRT of 30 s. The maximum elimination capacity (EC) was obtained in the DAS & RHS packed filter up to 52.32 g/m3h, with the RE of 96.87% and H2S mass loading rate of 54 g/m3h. The maximum EC in the DAS packed filter was obtained up to 44.33 g/m3h with the RE of 82.09% and the H2S mass loading rate of 54 g/m3h. After 53 days of operating time and 54 g/m3h of loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O) for the DAS & RHS packed and DAS packed filters, respectively. Based on the findings of this study, the DAS & RHS could be considered as a more suitable packing material to remove H2S. PMID:23497048

  19. Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic–Anoxic–Aerobic Activated Sludge System

    PubMed Central

    Zeng, Qingling; Li, Yongmei; Yang, Shijia

    2013-01-01

    Abstract Estrogen in wastewater are responsible for a significant part of the endocrine-disrupting effects observed in the aquatic environment. The effect of sludge retention time (SRT) on the removal and fate of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in an anaerobic–anoxic–oxic activated sludge system designed for nutrient removal was investigated by laboratory-scale experiments using synthetic wastewater. With a hydraulic retention time of 8 h, when SRT ranged 10–25 days, E2 was almost completely removed from water, and EE2 removal efficiency was 65%–81%. Both estrogens were easily sorbed onto activated sludge. Distribution coefficients (Kd) of estrogens on anaerobic sludge were greater than those on anoxic and aerobic sludges. Mass balance calculation indicated that 99% of influent E2 was degraded by the activated sludge process, and 1% remained in excess sludge; of influent EE2, 62.0%–80.1% was biodegraded; 18.9%–34.7% was released in effluent; and 0.88%–3.31% remained in excess sludge. Optimal SRT was 20 days for both estrogen and nutrient removal. E2 was almost completely degraded, and EE2 was only partly degraded in the activated sludge process. Residual estrogen on excess sludge must be considered in the sludge treatment and disposal processes. The originality of the work is that removal of nutrients and estrogens were linked, and optimal SRT for both estrogen and nutrient removal in an enhanced biological phosphorus removal system was determined. This has an important implication for the design and operation of full-scale wastewater treatment plants. PMID:23633892

  20. Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic-Anoxic-Aerobic Activated Sludge System.

    PubMed

    Zeng, Qingling; Li, Yongmei; Yang, Shijia

    2013-04-01

    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 (K d) of estrogens on anaerobic sludge were greater than those on anoxic and aerobic sludges. Mass balance calculation indicated that 99% of influent E2 was degraded by the activated sludge process, and 1% remained in excess sludge; of influent EE2, 62.0%-80.1% was biodegraded; 18.9%-34.7% was released in effluent; and 0.88%-3.31% remained in excess sludge. Optimal SRT was 20 days for both estrogen and nutrient removal. E2 was almost completely degraded, and EE2 was only partly degraded in the activated sludge process. Residual estrogen on excess sludge must be considered in the sludge treatment and disposal processes. The originality of the work is that removal of nutrients and estrogens were linked, and optimal SRT for both estrogen and nutrient removal in an enhanced biological phosphorus removal system was determined. This has an important implication for the design and operation of full-scale wastewater treatment plants. PMID:23633892

  1. [Detection of anaerobic processes and microorganisms in immobilized activated sludge of a wastewater treatment plant with intense aeration].

    PubMed

    Litti, Iu V; Nekrasova, V K; Kulikov, N I; Siman'kova, M V; Nozhevnikova, A N

    2013-01-01

    Attached activated sludge from the Krasnaya Polyana (Sochi) wastewater treatment plant was studied after the reconstruction by increased aeration and water recycle, as well as by the installation of a bristle carrier for activated sludge immobilization. The activated sludge biofilms developing under conditions of intense aeration were shown to contain both aerobic and anaerobic microorganisms. Activity of a strictly anaerobic methanogenic community was revealed, which degraded organic compounds to methane, further oxidized by aerobic methanotrophs. Volatile fatty acids, the intermediates of anaerobic degradation of complex organic compounds, were used by both aerobic and anaerobic microorganisms. Anaerobic oxidation of ammonium with nitrite (anammox) and the presence of obligate anammox bacteria were revealed in attached activated sludge biofilms. Simultaneous aerobic and anaerobic degradation of organic contaminants by attached activated sludge provides for high rates of water treatment, stability of the activated sludge under variable environmental conditions, and decreased excess sludge formation. PMID:25509405

  2. Development of an ATP measurement method suitable for xenobiotic treatment activated sludge biomass.

    PubMed

    Nguyen, Lan Huong; Chong, Nyuk-Min

    2015-09-01

    Activated sludge consumes a large amount of energy to degrade a xenobiotic organic compound. By tracking the energy inventory of activated sludge biomass during the sludge's degradation of a xenobiotic, any disadvantageous effect on the sludge's performance caused by energy deficiency can be observed. The purpose of this study was to develop a reliable and accurate method for measuring the ATP contents of activated sludge cells that were to degrade a xenobiotic organic. Cell disruption and cellular ATP extraction were performed by a protocol with which xenobiotic degrading activated sludge biomass was washed with SDS, treated by Tris and TCA, and followed by bead blasting. The suspension of disrupted cells was filtered before the filtrate was injected into HPLC that was set at optimal conditions to measure the ATP concentration therein. This extraction protocol and HPLC measurement of ATP was evaluated for its linearity, limits of detection, and reproducibility. Evaluation test results reported a R(2) of 0.999 of linear fit of ATP concentration versus activated sludge concentration, a LOD=0.00045mg/L, a LOQ=0.0015mg/L for HPLC measurement of ATP, a MDL=0.46mg/g SS for ATP extraction protocol, and a recovery efficiency of 96.4±2%. This method of ATP measurement was simple, rapid, reliable, and was unburdened of some limitations other methods may have. PMID:26210584

  3. Sequential anaerobic/aerobic digestion for enhanced sludge stabilization: comparison of the process performance for mixed and waste sludge [corrected].

    PubMed

    Tomei, M Concetta; Carozza, Nicola Antonello

    2015-05-01

    Sequential anaerobic-aerobic digestion has been demonstrated as a promising alternative for enhanced sludge stabilization. In this paper, a feasibility study of the sequential digestion applied to real waste activated sludge (WAS) and mixed sludge is presented. Process performance is evaluated in terms of total solid (TS) and volatile solid (VS) removal, biogas production, and dewaterability trend in the anaerobic and double-stage digested sludge. In the proposed digestion lay out, the aerobic stage was operated with intermittent aeration to reduce the nitrogen load recycled to the wastewater treatment plant (WWTP). Experimental results showed a very good performance of the sequential digestion process for both waste and mixed sludge, even if, given its better digestibility, higher efficiencies are observed for mixed sludge. VS removal efficiencies in the anaerobic stage were 48 and 50% for waste and mixed sludge, respectively, while a significant additional improvement of the VS removal of 25% for WAS and 45% for mixed sludge has been obtained in the aerobic stage. The post-aerobic stage, operated with intermittent aeration, was also efficient in nitrogen removal, providing a significant decrease of the nitrogen content in the supernatant: nitrification efficiencies of 90 and 97% and denitrification efficiencies of 62 and 70% have been obtained for secondary and mixed sludges, respectively. A positive effect due to the aerobic stage was also observed on the sludge dewaterability in both cases. Biogas production, expressed as Nm(3)/(kgVSdestroyed), was 0.54 for waste and 0.82 for mixed sludge and is in the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. PMID:25028317

  4. Bioproduction of volatile fatty acid from the fermentation of waste activated sludge for in situ denitritation.

    PubMed

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

    2016-04-01

    Waste activated sludge (WAS) fermentation integrated with denitritation (the reduction of nitrite to dinitrogen gas) at different pHs was investigated in batch-mode reactors over a 24-day period. The results showed that in comparison with controlled pHs, the volatile fatty acid (VFA) bioproduction for in situ denitritation was significantly improved at uncontrolled pH. VFA fermented from WAS was quickly consumed by denitritation at uncontrolled pH, which accelerated sludge degradation. On the other hand, sludge digestion was benefited from the alkalinity produced from denitritation, while methanogenesis was prohibited by alkalinity and nitrite. The integrated sludge fermentation and denitritation can be cost-effectively applied to wastewater treatment plants, so that organic substrates (e.g., VFAs) are produced for denitritation via simultaneous sludge fermentation, which enables WAS reutilization and enhances nitrogen removal efficiency without the need of external carbon sources. PMID:26475401

  5. Influence of Copper Nanoparticles on the Physical-Chemical Properties of Activated Sludge

    PubMed Central

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

    2014-01-01

    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. PMID:24663333

  6. Molecularly imprinted polymer microspheres enhanced biodegradation of bisphenol A by acclimated activated sludge.

    PubMed

    Xie, Ya-ting; Li, Hai-bin; Wang, Ling; Liu, Qian; Shi, Yun; Zheng, Hai-yan; Zhang, Meng; Wu, Ya-ting; Lu, Bin

    2011-01-01

    The impacts of bisphenol A- imprinted polymeric microspheres (MIPMs) on the biodegradation of bisphenol A by acclimated activated sludge were studied. Due to the selective adsorption of MIPMs to bisphenol A (BPA) and its analogues, addition of MIPMs to activated sludge increased levels of BPA and its metabolites, which were also the substrates of biodegradation. Higher substrates (BPA and its metabolites) level promoted biodegradation efficiencies of activated sludge via accelerating removal speed of BPA and its metabolites, increasing degradation rate and decreasing half-lives of biodegradation. The enhancement of MIPMs in degradation efficiencies was more significant in environmental water containing low-level of pollutants, and water containing interferences such as heavy metals and humic acid. Furthermore, MIPMs were more suitable than non-selective sorbents such as active carbon to be used as enhancer for BPA biodegradation. MIPMs combined with activated sludge are simple, effective, environmental-friendly processes to biodegrade low-level pollutants in environmental water. PMID:21131017

  7. [Using Excess Activated Sludge Treated 4-Chlorophenol Contained Waste Water to Cultivate Chlorella vulgaris].

    PubMed

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

    2015-04-01

    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. PMID:26164919

  8. Performance of calcium peroxide for removal of endocrine-disrupting compounds in waste activated sludge and promotion of sludge solubilization.

    PubMed

    Zhang, Ai; Wang, Jie; Li, Yongmei

    2015-03-15

    Removal of six phenolic endocrine disrupting compounds (EDCs) (estrone, 17β-estradiol, 17α-ethinylestradiol, estriol, bisphenol A, and 4-nonylphenols) from waste activated sludge (WAS) was investigated using calcium peroxide (CaO2) oxidation. Effects of initial pH and CaO2 dosage were investigated. The impacts of CaO2 treatment on sludge solubilization and anaerobic digestion were also evaluated. Specifically, the role of reactive oxygen species (ROS) in EDC degradation during CaO2 oxidation was tested. Effects of 6 metal ions contained in the sludge matrix on EDC degradation were also evaluated. The results showed that CaO2 treatment can be a promising technology for EDC removal and facilitating sludge reuse. The EDC removal efficiencies increased with the increase in CaO2 dosage. At CaO2 doses of more than 0.34 g per gram of total solid (g g(-1) TS), more than 50% of EDCs were removed in a wide pH range of 2-12. Higher removal efficiencies were achieved at initial pH values of 12 and 2. The products of EDCs during CaO2 oxidation had less estrogenic activity than the originals. Under the conditions of neutral pH and CaO2 dosage = 0.34 g g(-1) TS, the sludge solubilization can be improved by increasing the soluble total organic carbon (STOC) and volatile suspended solids (VSS) reduction by 25% and 27% in 7 d, respectively; the volatile fatty acid (VFA) production was enhanced by 96% in the 15 d following anaerobic digestion. The ROS released by CaO2 are the main factors contributing to EDC removal, among which, hydroxyl radicals (OH) play the most important role. Metal ions contained in the sludge matrix also affected EDC removal. For most cases, Fe, Cu, and Zn had positive effects; Mn and Ag had negative effects; and Mg had an insignificant effect on EDC removal. PMID:25613412

  9. Nitrification and microalgae cultivation for two-stage biological nutrient valorization from source separated urine.

    PubMed

    Coppens, Joeri; Lindeboom, Ralph; Muys, Maarten; Coessens, Wout; Alloul, Abbas; Meerbergen, Ken; Lievens, Bart; Clauwaert, Peter; Boon, Nico; Vlaeminck, Siegfried E

    2016-07-01

    Urine contains the majority of nutrients in urban wastewaters and is an ideal nutrient recovery target. In this study, stabilization of real undiluted urine through nitrification and subsequent microalgae cultivation were explored as strategy for biological nutrient recovery. A nitrifying inoculum screening revealed a commercial aquaculture inoculum to have the highest halotolerance. This inoculum was compared with municipal activated sludge for the start-up of two nitrification membrane bioreactors. Complete nitrification of undiluted urine was achieved in both systems at a conductivity of 75mScm(-1) and loading rate above 450mgNL(-1)d(-1). The halotolerant inoculum shortened the start-up time with 54%. Nitrite oxidizers showed faster salt adaptation and Nitrobacter spp. became the dominant nitrite oxidizers. Nitrified urine as growth medium for Arthrospira platensis demonstrated superior growth compared to untreated urine and resulted in a high protein content of 62%. This two-stage strategy is therefore a promising approach for biological nutrient recovery. PMID:26998796

  10. Incorporation of hydrophobized mineral particles in activated sludge flocs: a way to assess ballasting efficiency.

    PubMed

    Defontaine, G; Thormann, J; Lartiges, B S; El Samrani, A G; Barrs, O

    2005-01-01

    The role of mineral surface hydrophobicity in attachment to activated sludge flocs was investigated. Fluorite and quartz particles of similar granulometry were hydrophobized by adsorbing sodium oleate and dodecylamine chloride, respectively. Mineral hydrophobicity was assessed by flotation expriments. The attachment of particles to microbial flocs was determined by optical microscopy. The results indicate that hydrophobized particles are always better incorporated within activated sludge flocs than non-coated particles. A comparison with Aquatal particles used as sludge ballast reveals that hydrophobized minerals are associated with microbial flocs to the same extent. PMID:16459790

  11. [Activated Sludge Bacteria Transforming Cyanopyridines and Amides of Pyridinecarboxylic Acids].

    PubMed

    Demakov, V A; Vasil'ev, D M; Maksimova, Yu G; Pavlova, Yu A; Ovechkina, G V; Maksimov, A Yu

    2015-01-01

    Species diversity of bacteria from the activated sludge of Perm biological waste treatment facilities capable of transformation of cyanopyridines and amides of pyridinecarboxylic acids was investigated. Enrichment cultures in mineral media with 3-cyanopyridine as the sole carbon and nitrogen source were used to obtain 32 clones of gram-negative heterotrophic bacteria exhibiting moderate growth on solid and liquid media with 3- and 4-cyanopyridine. Sequencing of the 16S rRNA gene fragments revealed that the clones with homology of at least 99% belonged to the genera Acinetobacte, Alcaligenes, Delftia, Ochrobactrum, Pseudomonas, Stenotrophomonas, and Xanthobacter. PCR analysis showed that 13 out of 32 isolates contained the sequences (-1070 bp) homologous to the nitrilase genes reported previously in Alcaligenes faecalis JM3 (GenBank, D13419.1). Nine clones were capable of nitrile and amide transformation in minimal salt medium. Acinetobacter sp. 11 h and Alcaligenes sp. osv transformed 3-cyanopyridine to nicotinamide, while most of the clones possessed amidase activity (0.5 to 46.3 mmol/(g h) for acetamide and 0.1 to 5.6 mmol/(g h) for nicotinamide). Nicotinamide utilization by strain A. faecalis 2 was shown to result in excretion of a secondary metabolite, which was identified as dodecyl acrylate at 91% probability. PMID:26263697

  12. Activated sludge studies of selected contaminants of PFH wastewater

    SciTech Connect

    Dudley, S.K.; Bustamante, R.B.; Bonner, W.P.

    1991-12-31

    Acetone, propionitrile, pyrrole, and thiocyanate were selected as representative compounds of wastewater expected from pressurized, fluidized-bed hydroretorting (PFH) of Eastern oil shales. The PFH process has been the subject of investigation by the Institute of Gas Technology, under contract with the United States Department of Energy, for the purpose of obtaining higher oil yields from Eastern shales than has been possible using conventional retorting methods. Preliminary batch experiments illustrated that acetone, propionitrile, pyrrole, and thiocyanate are aerobically biodegradable by heterogeneous microbiological cultures. Three continuous flow activated sludge reactors were used to further evaluate the biological treatability of the synthetic waste. The studies revealed that the compounds could be removed at hydraulic residence times of as low as one day. Three one-day experiments demonstrated that biological system`s capability to accept organic shock loadings without a change in effluent quality. A no-recycle reactor illustrated that the flocculent microbiological population had a high resistance to solids washout. Because a supplementary nitrogen source was not included in synthetic waste treated by the no-recycle unit, it was shown that propionitrile, pyrrole, and/or thiocyanate supplied the nitrogen necessary for biological activity.

  13. Activated sludge studies of selected contaminants of PFH wastewater

    SciTech Connect

    Dudley, S.K. ); Bustamante, R.B.; Bonner, W.P. )

    1991-01-01

    Acetone, propionitrile, pyrrole, and thiocyanate were selected as representative compounds of wastewater expected from pressurized, fluidized-bed hydroretorting (PFH) of Eastern oil shales. The PFH process has been the subject of investigation by the Institute of Gas Technology, under contract with the United States Department of Energy, for the purpose of obtaining higher oil yields from Eastern shales than has been possible using conventional retorting methods. Preliminary batch experiments illustrated that acetone, propionitrile, pyrrole, and thiocyanate are aerobically biodegradable by heterogeneous microbiological cultures. Three continuous flow activated sludge reactors were used to further evaluate the biological treatability of the synthetic waste. The studies revealed that the compounds could be removed at hydraulic residence times of as low as one day. Three one-day experiments demonstrated that biological system's capability to accept organic shock loadings without a change in effluent quality. A no-recycle reactor illustrated that the flocculent microbiological population had a high resistance to solids washout. Because a supplementary nitrogen source was not included in synthetic waste treated by the no-recycle unit, it was shown that propionitrile, pyrrole, and/or thiocyanate supplied the nitrogen necessary for biological activity.

  14. Combined System of Activated Sludge and Ozonation for the Treatment of Kraft E1 Effluent

    PubMed Central

    Assalin, Marcia Regina; dos Santos Almeida, Edna; Durán, Nelson

    2009-01-01

    The treatment of paper mill effluent for COD, TOC, total phenols and color removal was investigated using combined activated sludge-ozonation processes and single processes. The combined activated sludge-O3/pH 10 treatment was able to remove around 80% of COD, TOC and color from Kraft E1 effluent. For the total phenols, the efficiency removal was around 70%. The ozonation post treatment carried out at pH 8.3 also showed better results than the single process. The COD, TOC, color and total phenols removal efficiency obtained were 75.5, 59.1, 77 and 52.3%, respectively. The difference in the concentrations of free radical produced by activated sludge-O3/pH 10 and activated sludge-O3/pH 8.3 affected mainly the TOC and total phenol removal values. PMID:19440438

  15. EVIDENCE THAT MICROORGANISMS CAUSE INACTIVATION OF VIRUSES IN ACTIVATED SLUDGE (JOURNAL VERSION)

    EPA Science Inventory

    Virus loss in activated sludge appeared to be caused by microorganisms. This conclusion is supported by the finding that poliovirus infectivity decreased during incubation in mixed-liquor suspended solids, primarily because of a sedimentable, heat-sensitive component. Furthermore...

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

    PubMed

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

    2015-01-01

    In order to find out the effects of humic acid (HA) in anaerobic-treated landfill leachate on granular sludge, the anaerobic biodegradability of HA as well as the influences of HA on the total cumulative methane production, the anaerobic methanization process and the specific methanogenic activity (SMA) of granular sludge are studied in this paper. Experimental results show that as a non-biodegradable organic pollutant, HA is also difficult to be decomposed by microbes in the anaerobic reaction process. Presence of HA and changes in the concentration have no significant influences on the total cumulative methane production and the anaerobic methanization process of granular sludge. Besides, the total cumulative methane production cannot reflect the inhibition of toxics on the methanogenic activity of granular sludge on the premise of sufficient reaction time. Results also show that HA plays a promoting role on SMA of granular sludge. Without buffering agent the SMA value increased by 19.2% on average due to the buffering and regulating ability of HA, while with buffering agent the SMA value increased by 5.4% on average due to the retaining effect of HA on the morphology of the sludge particles. However, in the presence of leachate the SMA value decreased by 27.6% on average, because the toxic effect of the toxics in the leachate on granular sludge is much larger than the promoting effect of HA. PMID:25915186

  17. Comparison of extracellular polymeric substances (EPS) extraction from two different activated sludges.

    PubMed

    Zhang, Leiyan; Ren, Hongqiang; Ding, Lili

    2012-01-01

    The characteristics of extracellular polymeric substances (EPS) extracted with five different extraction protocols from two different activated sludges were studied. The results showed that the major EPS constituent extracted by centrifugation was protein for the sludge in sequencing batch reactor treating chemical wastewater, and nucleic acid for the sludge in moving bed biofilm reactor treating synthetic urban wastewater. The order of EPS extraction amounting from the two sludges was formaldehyde + NaOH > formaldehyde + heating > EDTA > heating > centrifugation. The different extraction methods, the wastewater type, and activated sludge source greatly affected the amount and composition of EPS. The chemical extracted methods were more effective than the physical methods in extracting EPS for the two sludges. Moreover, formaldehyde combined NaOH was most effective in extracting EPS for the two sludges. However, chemical extraction could contaminate the EPS solution, which was pointed out by infra-red analysis and was also proved by cell lyses during EPS extraction and carrying over of the chemical extractant. Therefore, this study highlights that the choice of EPS extraction method should consider both the extraction yield and content and the contamination of extracting reagents to the EPS solution. The extraction procedures should be optimized and most effective. PMID:22864444

  18. Biotransformation and adsorption of pharmaceutical and personal care products by activated sludge after correcting matrix effects.

    PubMed

    Deng, Yu; Li, Bing; Yu, Ke; Zhang, Tong

    2016-02-15

    This study reported significant suppressive matrix effects in analyses of six pharmaceutical and personal care products (PPCPs) in activated sludge, sterilized activated sludge and untreated sewage by ultra-performance liquid chromatography-tandem mass spectrometry. Quantitative matrix evaluation on selected PPCPs supplemented the limited quantification data of matrix effects on mass spectrometric determination of PPCPs in complex environment samples. The observed matrix effects were chemical-specific and matrix-dependent, with the most pronounced average effect (-55%) was found on sulfadiazine in sterilized activated sludge. After correcting the matrix effects by post-spiking known amount of PPCPs, the removal mechanisms and biotransformation kinetics of selected PPCPs in activated sludge system were revealed by batch experiment. Experimental data elucidated that the removal of target PPCPs in the activated sludge process was mainly by biotransformation while contributions of adsorption, hydrolysis and volatilization could be neglected. High biotransformation efficiency (52%) was observed on diclofenac while other three compounds (sulfadiazine, sulfamethoxazole and roxithromycin) were partially biotransformed by ~40%. The other two compounds, trimethoprim and carbamazepine, showed recalcitrant to biotransformation of the activated sludge. PMID:26706769

  19. Disturbance opens recruitment sites for bacterial colonization in activated sludge.

    PubMed

    Vuono, David C; Munakata-Marr, Junko; Spear, John R; Drewes, Jörg E

    2016-01-01

    Little is known about the role of immigration in shaping bacterial communities or the factors that may dictate success or failure of colonization by bacteria from regional species pools. To address these knowledge gaps, the influence of bacterial colonization into an ecosystem (activated sludge bioreactor) was measured through a disturbance gradient (successive decreases in the parameter solids retention time) relative to stable operational conditions. Through a DNA sequencing approach, we show that the most abundant bacteria within the immigrant community have a greater probability of colonizing the receiving ecosystem, but mostly as low abundance community members. Only during the disturbance do some of these bacterial populations significantly increase in abundance beyond background levels and in few cases become dominant community members post-disturbance. Two mechanisms facilitate the enhanced enrichment of immigrant populations during disturbance: (i) the availability of resources left unconsumed by established species and (ii) the increased availability of niche space for colonizers to establish and displace resident populations. Thus, as a disturbance decreases local diversity, recruitment sites become available to promote colonization. This work advances our understanding of microbial resource management and diversity maintenance in complex ecosystems. PMID:25727891

  20. Biodegradation of imidazolium ionic liquids by activated sludge microorganisms.

    PubMed

    Liwarska-Bizukojc, Ewa; Maton, Cedric; Stevens, Christian V

    2015-11-01

    Biological properties of ionic liquids (ILs) have been usually tested with the help of standard biodegradation or ecotoxicity tests. So far, several articles on the identification of intermediate metabolites of microbiological decay of ILs have been published. Simultaneously, the number of novel ILs with unrecognized characteristics regarding biodegradability and effect on organisms and environment is still increasing. In this work, seven imidazolium ionic liquids of different chemical structure were studied. Three of them are 1-alkyl-3-methyl-imidazolium bromides, while the other four are tetra- or completely substituted imidazolium iodides. This study focused on the identification of intermediate metabolites of the aforementioned ionic liquids subjected to biodegradation in a laboratory activated sludge system. Both fully substituted ionic liquids and 1-ethyl-3-methyl-imidazolium bromide were barely biodegradable. In the case of two of them, no biotransformation products were detected. The elongation of the alkyl side chain made the IL more susceptible for microbiological decomposition. 1-Decyl-3-methyl-imidazolium bromide was biotransformed most easily. Its primary biodegradation up to 100 % could be achieved. Nevertheless, the cleavage of the imidazolium ring has not been observed. PMID:26463469

  1. Aerobic activated sludge transformation of methotrexate: identification of biotransformation products.

    PubMed

    Kosjek, Tina; Negreira, Noelia; de Alda, Miren López; Barceló, Damià

    2015-01-01

    This study describes the biotransformation of cytostatic and immunosuppressive pharmaceutical methotrexate. Its susceptibility to microbiological breakdown was studied in a batch biotransformation system, in presence or absence of carbon source and at two activated sludge concentrations. The primary focus of the present study are methotrexate biotransformation products, which were tentatively identified by the ultra-high performance liquid chromatography-quadrupole--Orbitrap-MS. Data-dependent experiments, combining full-scan MS data with product ion spectra were acquired, in order to identify the molecular ions of methotrexate transformation products, to propose the molecular formulae and to elucidate their chemical structures. Among the identified transformation products 2,4-diamino-N10-methyl-pteroic acid is most abundant and persistent. Other biotransformation reactions involve demethylation, oxidative cleavage of amine, cleavage of C-N bond, aldehyde to carboxylate transformation and hydroxylation. Finally, a breakdown pathway is proposed, which shows that most of methotrexate breakdown products retain the diaminopteridine structural segment. In total we propose nine transformation products, among them eight are described as methotrexate transformation products for the first time. PMID:24835159

  2. A hundred years of activated sludge: time for a rethink

    PubMed Central

    Sheik, Abdul R.; Muller, Emilie E. L.; Wilmes, Paul

    2014-01-01

    Biological wastewater treatment plants (BWWTPs) based on the activated sludge (AS) process have dramatically improved worldwide water sanitation despite increased urbanization and industrialization. However, current AS-based operations are considered economically and environmentally unsustainable. In this Perspective, we discuss our current understanding of microbial populations and their metabolic transformations in AS-based BWWTPs in view of developing more sustainable processes in the future. In particular, much has been learned over the course of the past 25 years about specialized microorganisms, which could be more comprehensively leveraged to recover energy and/or nutrients from wastewater streams. To achieve this, we propose a bottom-up design approach, focused around the concept of a “wastewater biorefinery column”, which would rely on the engineering of distinct ecological niches into a BWWTP in order to guarantee the targeted enrichment of specific organismal groups which in turn will allow the harvest of high-value resources from wastewater. This concept could be seen as a possible grand challenge to microbial ecologists and engineers alike at the centenary of the discovery of the AS process. PMID:24624120

  3. Integration of microbial fuel cell techniques into activated sludge wastewater treatment processes to improve nitrogen removal and reduce sludge production.

    PubMed

    Gajaraj, Shashikanth; Hu, Zhiqiang

    2014-12-01

    Bioelectrochemical systems are emerging for wastewater treatment, yet little is known about how well they can be integrated with current wastewater treatment processes. In this bench-scale study, the microbial fuel cell (MFC) technique was incorporated into the Modified Ludzack-Ettinger (MLE) process (phase I) and later with the membrane bioreactor (MBR) process (phase II) to evaluate the performance of MFC assisted wastewater treatment systems (i.e., MLE-MFC and MBR-MFC). There was no significant difference in the effluent NH4(+)-N concentration between the systems integrating MFC and the open circuit controls. The average effluent COD concentration was significantly lower in the MLE-MFC, but it did not change much in the MBR-MFC because of the already low COD concentrations in MBR operation. The MLE-MFC and MBR-MFC systems increased the NO3(-)-N removal efficiencies by 31% (±12%) and 20% (±12%), respectively, and reduced sludge production by 11% and 6%, respectively, while generating an average voltage of 0.13 (±0.03) V in both systems. Analysis of the bacterial specific oxygen uptake rate, the sludge volume index, and ammonia-oxidizing bacterial population (dominated by Nitrosomonas through terminal restriction fragment length polymorphism analysis) indicated that there was no significant difference in sludge activity, settling property, and nitrifying community structure between the MFC assisted systems and the open circuit controls. The results suggest that the wastewater treatment systems could achieve higher effluent water quality and lower sludge production if it is integrated well with MFC techniques. PMID:25014565

  4. Ultrasonic waste activated sludge disintegration for recovering multiple nutrients for biofuel production.

    PubMed

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Qilin; Ding, Jie; Ren, Nan-Qi

    2016-04-15

    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. PMID:26896823

  5. [Effect of microbial aggregation state on nitrous oxide emission in simultaneous nitrification and denitrification nitrogen removal process].

    PubMed

    Yin, Qian-Ting; Li, Ping; Wu, Jin-Hua; Wang, Xiang-De

    2011-07-01

    In order to realize efficient nitrogen removal and N2O emission reduction, air lift circulation bioreactors were applied to study the relationship between activated sludge aggregation state and N2O emission characters on the basis of high nitrogen removal performance. The nitrification/denitrification activity of different microbial aggregates was evaluated by key enzyme action ratio method. Combined with correlative theoretical analysis, the optimal aggregation state with efficient nitrogen removal and N2O emission reduction was selected. According to the results, different activated sludge aggregation state in SND would lead to significant difference of N2O emission amount (> or = 40%). The smaller aggregates (< or = 0.9 mm) with moderate compactness could keep high SND efficiency (> or = 70%) and achieved N2O emission reduction. In experimental defined system, the optimal diameter of aggregates was in the range of 0.45-0.9 mm, which could obtain higher nitrification activity [ammonia-oxidizing bacteria activity was 0.17 mg x (g x min) (-1), nitrite-oxidizing bacteria activity was 0.74 mg x (g x min) (-1)] and denitrification activity [NO3(-) -N consumption rate was 0.47 mg x (g x min) (-1), NO2(-) -N consumption rate was 0.22 mg x (g x min) (-1)]. Compared to the control group, N2O accumulated emission amount in the reactor with aggregates of 0.45-0.9 mm could be realized reduction more than 32.55%. PMID:21922830

  6. Is anaerobic digestion effective for the removal of organic micropollutants and biological activities from sewage sludge?

    PubMed

    Gonzalez-Gil, L; Papa, M; Feretti, D; Ceretti, E; Mazzoleni, G; Steimberg, N; Pedrazzani, R; Bertanza, G; Lema, J M; Carballa, M

    2016-10-01

    The occurrence of emerging organic micropollutants (OMPs) in sewage sludge has been widely reported; nevertheless, their fate during sludge treatment remains unclear. The objective of this work was to study the fate of OMPs during mesophilic and thermophilic anaerobic digestion (AD), the most common processes used for sludge stabilization, by using raw sewage sludge without spiking OMPs. Moreover, the results of analytical chemistry were complemented with biological assays in order to verify the possible adverse effects (estrogenic and genotoxic) on the environment and human health in view of an agricultural (re)use of digested sludge. Musk fragrances (AHTN, HHCB), ibuprofen (IBP) and triclosan (TCS) were the most abundant compounds detected in sewage sludge. In general, the efficiency of the AD process was not dependent on operational parameters but compound-specific: some OMPs were highly biotransformed (e.g. sulfamethoxazole and naproxen), while others were only slightly affected (e.g. IBP and TCS) or even unaltered (e.g. AHTN and HHCB). The MCF-7 assay evidenced that estrogenicity removal was driven by temperature. The Ames test did not show point mutation in Salmonella typhimurium while the Comet test exhibited a genotoxic effect on human leukocytes attenuated by AD. This study highlights the importance of combining chemical analysis and biological activities in order to establish appropriate operational strategies for a safer disposal of sewage sludge. Actually, it was demonstrated that temperature has an insignificant effect on the disappearance of the parent compounds while it is crucial to decrease estrogenicity. PMID:27344252

  7. Effect of sole nitrogen sources and temperature on activated sludge

    SciTech Connect

    Mines, R.O. Jr.; Sherrard, J.H.

    1999-07-01

    The effects of temperature on biokinetic coefficients used to design aerobic biological systems treating nitrogen deficient wastewaters at a COD: TKN ratio of 13.7:1 are presented. The impact of temperature on substrate removal, waste biosolids production, and oxygen requirements with the effects of nitrification is delineated at temperatures of 5 C, 10 C, 20 C, and 30 C for two nitrogen sources; ammonia and nitrate. Temperature correction coefficients ({theta}) are presented and the implications for the design and operation of suspended growth biological systems are discussed.

  8. Parameter identification and modeling of the biochemical methane potential of waste activated sludge.

    PubMed

    Appels, Lise; Lauwers, Joost; Gins, Geert; Degrève, Jan; Van Impe, Jan; Dewil, Raf

    2011-05-01

    Anaerobic digestion is widely used in waste activated sludge treatment. In this paper, partial least-squares (PLS) is employed to identify the parameters that are determining the biochemical methane potential (BMP) of waste activated sludge. Moreover, a model is developed for the prediction of the BMP. A strong positive correlation is observed between the BMP and volatile fatty acids and carbohydrate concentrations in the sludge. A somewhat weaker correlation with COD is also present. Soluble organics (sCOD, soluble carbohydrates and soluble proteins) were shown not to influence the BMP in the observed region. This finding could be most-valuable in the context of application of sludge pretreatment methods. The obtained model was able to satisfactory predict the BMP. PMID:21476497

  9. NITRIFICATION BY ASPERGILLUS FLAVUS1

    PubMed Central

    Marshall, K. C.; Alexander, M.

    1962-01-01

    Marshall, K. C. (Cornell University, Ithaca, N. Y.) and M. Alexander. Nitrification by Aspergillus flavus. J. Bacteriol. 83:572–578. 1962.—Aspergillus flavus has been shown to produce bound hydroxylamine, nitrite, and nitrate when grown in peptone, amino acid, or buffered ammonium media. Free hydroxylamine was not detected in these cultures, but it was found in an unbuffered ammonium medium in which neither nitrite nor nitrate was formed. Evidence was obtained for the presence of β-nitropropionic acid in the filtrate of an actively nitrifying culture. Alumina treatment of an ammonium medium prevented the formation by growing cultures of nitrite and nitrate but not bound hydroxylamine. The effect of alumina treatment was reversed by the addition of 10−3m CeCl3 to the medium. Extracts of the fungus contained peroxidase and an enzyme capable of catalyzing the production of nitrite from β-nitropropionic acid. The nitrite-forming enzyme is apparently specific for β-nitropropionate; no activity was found with nitromethane, nitroethane, and nitropropane as substrates. Nitrate was not reduced to nitrite nor was nitrite oxidized to nitrate by the hyphal extracts. The significance of these observations in nitrification by A. flavus is discussed. PMID:14470254

  10. Comparison of imidazolium ionic liquids and traditional organic solvents: effect on activated sludge processes.

    PubMed

    Gendaszewska, Dorota; Liwarska-Bizukojc, Ewa

    2013-01-01

    Data concerning the biodegradability and ecotoxicity of ionic liquids (ILs) obtained so far are insufficient in the context of IL removal from wastewater in activated sludge systems. Thus, in this work the selected imidazolium ionic liquids and two organic solvents (methanol and acetone) were tested with respect to their influence on activated sludge processes, particularly on the morphology of sludge flocs. The presence of ionic liquids with the chemical structure of 1-alkyl-3-methyl imidazolium bromide in wastewater did not deteriorate biological wastewater treatment processes if their concentration was not higher than 5 mg l(-1). Regarding the structure of the ILs studied, the longer the alkyl substituent was, the stronger the effect on sludge flocs. The highest decrease in activated sludge floc area and biomass concentration was exerted by the ionic liquid with the longest alkyl chain, i.e. 1-decyl-3-methylimidazolium bromide. The action of both methanol and acetone on floc size, activated sludge concentration and efficiency of organic pollutants removal was weaker compared to all tested 1-alkyl-3-methyl imidazolium bromides. PMID:24355854

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

    PubMed

    Foissner, Wilhelm

    2016-08-01

    When the activated sludge process was developed, operators and scientists soon recognized protists as valuable indicators. However, only when Curds et al. (1968) showed with a few photographs the need of ciliates for a clear plant effluent, sewage protistology began to bloom but was limited by the need of species identification. Still, this is a major problem although several good guides are available. Thus, molecular kits should be developed for identification. Protists are indicators in two stages of wastewater treatment, viz., in the activated sludge and in the environmental water receiving the plant effluent. Continuous control of the protist and bacterial communities can prevent biological sludge foaming and bulking and may greatly save money for sludge oxygenation because several protist species are excellent indicators for the amount of oxygen present. The investigation of the effluent-receiving rivers gives a solid indication about the long term function of sewage works. The literature on protist bioindication in activated sludge is widely distributed. Thus, I compiled the data in a simple Table, showing which communities and species indicate good, mediocre, or poor plant performance. Further, many details on indication are provided, such as sludge loading and nitrifying conditions. Such specific features should be improved by appropriate statistics and more reliable identification of species. Then, protistologists have a fair chance to become important in wastewater works. Activated sludge is a unique habitat for particular species, often poorly or even undescribed. As an example, I present two new species. The first is a minute (∼30μm) Metacystis that makes an up to 300μm-sized mucous envelope mimicking a sludge floc. The second is a Phialina that is unique in having the contractile vacuole slightly posterior to mid-body. Finally, I provide a list of species which have the type locality in sewage plants. PMID:27062305

  12. The influence of hydrolysis induced biopolymers from recycled aerobic sludge on specific methanogenic activity and sludge filterability in an anaerobic membrane bioreactor.

    PubMed

    Buntner, D; Spanjers, H; van Lier, J B

    2014-03-15

    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. PMID:24284260

  13. Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, part II: multilayer biofilm diffusional model.

    PubMed

    Sen, Dipankar; Randall, Clifford W

    2008-07-01

    Research was undertaken to develop a diffusional model of the biofilm that can be applied in lieu of a semi-empirical model to upgrade an activated sludge system to an integrated fixed-film activated sludge (IFAS) or moving-bed biofilm reactor (MBBR) system. The model has been developed to operate with up to 12 cells (reactors) in series, with biofilm media incorporated to one or more of the zone cells, except the anaerobic zone cells. The values of the kinetic parameters for the model were measured using pilot-scale activated sludge, IFAS, and MBBR systems. The biofilm is divided into 12 layers and has a stagnant liquid layer. Diffusion and substrate utilization are calculated for each layer. The equations are solved simultaneously using a finite difference technique. The biofilm flux model is then linked to the activated sludge model. Advanced features include the ability to compute the biofilm thickness and the effect of biofilm thickness on performance. The biofilm diffusional model is also used to provide information and create a table of biofilm yields at different substrate concentrations that can be used in the semi-empirical model. PMID:18710146

  14. Influence of bulking agents and microbial activator on thermophilic aerobic transformation of sewage sludge.

    PubMed

    Pasda, N; Limtong, P; Oliver, R; Montange, D; Panichsakpatana, S

    2005-10-01

    Bangkok, while improving the wastewater treatment in order to alleviate the river pollution, faces important amounts of sewage sludge. The sewage sludge contains organic matter, nitrogen and phosphorus available for plant growth. However, it may contain pathogenic microorganisms. To be used for agricultural purposes, these pathogens should be destroyed, which can be achieved with the thermophilic phase of composting. As the sewage sludge is dense and unable to compost alone (low C/N ratio), it should be mixed with an organic by-product. Two by-products available in large quantities in Thailand (wood chips and rice husk) have been tested for mixture with sewage sludge. As these products are not easy to decompose (presence of silica in rice husk and lignin/tannins in wood chips), the addition of a microbial activator for composting has been tested in controlled conditions (small quantities of organic mixtures, 55 degrees C, moisture maintained at 60-70% of water holding capacity). The monitoring of the decomposition has been made by measuring the carbon dioxide respiration, pH, organic matter and nitrogen contents and the evolution of enzymatic activities. When mixed with sewage sludge, wood chips and rice husk do not show significant differences concerning decomposition after 63 days. The use of an activator within the experimental conditions does not improve the decomposition of organic matter contained in the mixture of sewage sludge and rice husk or wood chips. PMID:16342535

  15. Nitrification in Beef Cattle Feedlot Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background and Aims: Ammonia volatilization is the primary route for nitrogen loss from cattle feedlots. An additional, but poorly studied mechanism in feedlots is aerobic nitrification. The aim of this study is to characterize nitrifier activity, abundance, and diversity for a cattle production ...

  16. Identical full-scale biogas-lift reactors (Blrs) with anaerobic granular sludge and residual activated sludge for brewery wastewater treatment and kinetic modeling.

    PubMed

    Xu, Fu; Huang, Zhenxing; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing; Ruan, Wenquan

    2013-10-01

    Two identical full-scale biogas-lift reactors treating brewery wastewater were inoculated with different types of sludge to compare their operational conditions, sludge characteristics, and kinetic models at a mesophilic temperature. One reactor (R1) started up with anaerobic granular sludge in 12 weeks and obtained a continuously average organic loading rate (OLR) of 7.4 kg chemical oxygen demand (COD)/(m3 x day), COD removal efficiency of 80%, and effluent COD of 450 mg/L. The other reactor (R2) started up with residual activated sludge in 30 weeks and granulation accomplished when the reactor reached an average OLR of 8.3 kg COD/(m3 x day), COD removal efficiency of 90%, and effluent COD of 240 mg/L. Differences in sludge characteristics, biogas compositions, and biogas-lift processes may be accounted for the superior efficiency of the treatment performance of R2 over R1. Grau second-order and modified StoverKincannon models based on influent and effluent concentrations as well as hydraulic retention time were successfully used to develop kinetic parameters of the experimental data with high correlation coefficients (R2 > 0.95), which further showed that R2 had higher treatment performance than R1. These results demonstrated that residual activated sludge could be used effectively instead of anaerobic granular sludge despite the need for a longer time. PMID:24494489

  17. Kinetic evaluation of nitrification performance in an immobilized cell membrane bioreactor.

    PubMed

    Güven, D; Ubay Çokgör, E; Sözen, S; Orhon, D

    2016-01-01

    High rate membrane bioreactor (MBR) systems operated at extremely low sludge ages (superfast membrane bioreactors (SFMBRs)) are inefficient to achieve nitrogen removal, due to insufficient retention time for nitrifiers. Moreover, frequent chemical cleaning is required due to high biomass flux. This study aims to satisfy the nitrification in SFMBRs by using sponge as carriers, leading to the extension of the residence time of microorganisms. In order to test the limits of nitrification, bioreactor was run under 52, 5 and 2 days of carrier residence time (CRT), with a hydraulic retention time of 6 h. Different degrees of nitrification were obtained for different CRTs. Sponge immobilized SFMBR operation with short CRT resulted in partial nitrification indicating selective dominancy of ammonia oxidizers. At higher CRT, simultaneous nitrification-denitrification was achieved when accompanying with oxygen limitation. Process kinetics was determined through evaluation of the results by a modeling study. Nitrifier partition in the reactor was also identified by model calibration. PMID:27332835

  18. Short- and long-term effects of temperature on partial nitrification in a sequencing batch reactor treating domestic wastewater.

    PubMed

    Guo, Jianhua; Peng, Yongzhen; Huang, Huijun; Wang, Shuying; Ge, Shijian; Zhang, Jingrong; Wang, Zhongwei

    2010-07-15

    Partial nitrification to nitrite has been frequently obtained at high temperatures, but has proved difficult to achieve at low temperatures when treating low strength domestic wastewater. In this study, the long-term effects of temperature on partial nitrification were investigated by operating a sequencing bath reactor with the use of aeration duration control. The specific ammonia oxidation rate decreased by 1.5 times with the temperature decreasing from 25 to 15 degrees C. However, low temperature did not deteriorate the stable partial nitrification performance. Nitrite accumulation ratio was always above 90%, even slightly higher (above 95%) at low temperatures. The nitrifying sludge accumulated with ammonia-oxidizing bacteria (AOB), but washout of nitrite-oxidizing bacteria (NOB) was used to determine the short-term effects of temperature on ammonia oxidation process. The ammonia oxidation rate depended more sensitively on lower temperatures; correspondingly the temperature coefficient theta was 1.172 from 5 to 20 degrees C, while theta was 1.062 from 20 to 35 degrees C. Moreover, the larger activation energy (111.5 kJ mol(-1)) was found at lower temperatures of 5-20 degrees C, whereas the smaller value (42.0 kJ mol(-1)) was observed at higher temperatures of 20-35 degrees C. These findings might be contributed to extend the applicability of the partial nitrification process in wastewater treatment plants operated under cold weather conditions. It is suggested that the selective enrichment of AOB as well as the washout of NOB be obtained by process control before making the biomass slowly adapt to low temperatures for achieving partial nitrification to nitrite at low temperatures. PMID:20381239

  19. [Research on the treatment of wastewater containing PVA by ozonation-activated sludge process].

    PubMed

    Xing, Xiao-Qiong; Huang, Cheng-Lan; Liu, Min; Chen, Ying

    2012-11-01

    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. PMID:23323416

  20. Roseomonas eburnea sp. nov., isolated from activated sludge.

    PubMed

    Wang, Chenghong; Deng, Shikai; Liu, Xin; Yao, Li; Shi, Chao; Jiang, Jin; Kwon, Soon-Wo; He, Jian; Li, Jiayou

    2016-01-01

    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). PMID:26530339

  1. Ornithinimicrobium pekingense sp. nov., isolated from activated sludge.

    PubMed

    Liu, Xing-Yu; Wang, Bao-Jun; Jiang, Cheng-Ying; Liu, Shuang-Jiang

    2008-01-01

    The bacterial strain LW6(T) was isolated from activated sludge of a wastewater treatment bioreactor. Cells of strain LW6(T) are Gram-positive, irregular, short rods and cocci, 0.5-0.8x1.0-1.6 microm. Colonies are light-yellow, smooth, circular and 0.2-1.0 mm in diameter after 3 days incubation. Strain LW6(T) is aerobic and heterotrophic. It grows at a temperature range of 26-38 degrees C and pH range of 6-9, with optimal growth at 33-37 degrees C and pH 7.8-8.2. The predominant cellular fatty acids of strain LW6(T) are iso-C(15:0) (38.9%) and iso-C(17:1)omega9c (18.8%). Strain LW6(T) has the major respiratory menaquinones MK-8(H(4)) and MK-8(H(2)) and polar lipids phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol and unknown glycolipid/phospholipids. The cell wall peptidoglycan of strain LW6(T) contained the amino acids ornithine, lysine, glutamic acid, alanine, glycine and aspartic acid. Its molar DNA G+C content is 69 mol% (T(m)). Analysis of 16S rRNA gene sequences indicated that strain LW6(T) was related phylogenetically to members of the genus Ornithinimicrobium, with similarities ranging from 98.3 to 98.7%. The DNA-DNA relatedness of strain LW6(T) to Ornithinimicrobium humiphilum DSM 12362(T) and Ornithinimicrobium kibberense K22-20(T) was respectively 31.5 and 15.2%. Based on these results, it is concluded that strain LW6(T) represents a novel species of the genus Ornithinimicrobium, for which the name Ornithinimicrobium pekingense sp. nov. is proposed. The type strain is strain LW6(T) (=CGMCC 1.5362(T) =JCM 14001(T)). PMID:18175694

  2. Chryseomicrobium aureum sp. nov., a bacterium isolated from activated sludge.

    PubMed

    Deng, Shi-Kai; Ye, Xiao-Mei; Chu, Cui-Wei; Jiang, Jin; He, Jian; Zhang, Jun; Li, Shun-Peng

    2014-08-01

    A Gram-stain-positive, rod-shaped, non-motile, non-spore-forming, aerobic bacterial strain, designated BUT-2(T), was isolated from activated sludge of one herbicide-manufacturing wastewater-treatment facility in Kunshan, Jiangsu province, China, and subjected to polyphasic taxonomic studies. Analysis of the 16S rRNA gene sequence indicated that strain BUT-2(T) shared the highest similarity with Chryseomicrobium amylolyticum (98.98%), followed by Chryseomicrobium imtechense (98.88%), with less than 96% similarlity to members of the genera Paenisporosarcina, Planococcus, Sporosarcina and Planomicrobium. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain BUT-2(T) clustered with C. amylolyticum JC16(T) and C. imtechense MW10(T), occupying a distinct phylogenetic position. The major fatty acid (>10% of total fatty acids) type of strain BUT-2(T) was iso-C(15 : 0). The quinone system comprised menaquinone MK-7 (77.8%), MK-6 (11.9%) and MK-8 (10.3%). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and some unidentified phospholipids. The cell-wall peptidoglycan type of strain BUT-2(T) was L-Orn-D-Glu. The genomic DNA G+C content of strain BUT-2(T) was 48.5 mol%. Furthermore, the DNA-DNA relatedness in hybridization experiments against the reference strain was lower than 70%, confirming that strain BUT-2(T) did not belong to previously described species of the genus Chryseomicrobium. On the basis of its morphological, physiological and chemotaxonomic characteristics as well as phylogenetic analysis, strain BUT-2(T) is considered to represent a novel species of the genus Chryseomicrobium, for which the name Chryseomicrobium aureum sp. nov. is proposed. The type strain is BUT-2(T) ( = CCTCC AB2013082(T) = KACC 17219(T)). PMID:24827708

  3. Nitrification in a zeoponic substrate

    NASA Technical Reports Server (NTRS)

    McGilloway, R. L.; Weaver, R. W.; Ming, D. W.; Gruener, J. E.

    2003-01-01

    Clinoptilolite is a zeolite mineral with high cation exchange capacity used in zeoponic substrates that have been proposed as a solid medium for growing plants or as a fertilizer material. The kinetics of nitrification has not been measured for NH4+ saturated zeoponic substrate. Experiments were conducted to evaluate the production of NO2- and NO3-, and nitrifier populations in zeoponic substrates. Small columns were filled with zeoponic substrate inoculated with a commercial inoculum or soil enrichment culture of nitrifying bacteria. In addition to column studies, a growth chamber study was conducted to evaluate the kinetics of nitrification in zeoponic substrates used to grow radishes (Raphanus sativus L.). The zeoponic substrate provided a readily available source of NH4+, and nitrifying bacteria were active in the substrate. Ammonium oxidation rates in column studies ranged from 5 to 10 micrograms N g-1 substrate h-1, and NO2- oxidation rates were 2 to 9.5 micrograms N g-1 substrate h-1. Rates determined from the growth chamber study were approximately 1.2 micrograms N g-1 substrate h-1. Quantities of NH4+ oxidized to NO2- and NO3- in inoculated zeoponic substrate were in excess of plant up-take. Acidification as a result of NH4+ oxidation resulted in a pH decline, and the zeoponic substrate showed limited buffering capacity.

  4. Enhancing denitrification using a carbon supplement generated from the wet oxidation of waste activated sludge.

    PubMed

    Strong, P J; McDonald, B; Gapes, D J

    2011-05-01

    This study compared the effect of four pure carbon supplements on biological denitrification to a liquor derived as a by-product from the wet oxidation (WO) of waste activated sludge. Sequencing batch reactors were used to acclimate sludge biomass, which was used in batch assays. Acetate, WO liquor and ethanol-supplementation generated the fastest denitrification rates. Acetate and WO liquor were efficiently utilised by all acclimated biomass types, while poor rates were achieved with methanol and formate. When comparing an inoculum from an ethanol-supplemented and non-supplemented wastewater treatment plant (WWTP), the ethanol-acclimated sludge obtained superior denitrification rates when supplemented with ethanol. Similarly high nitrate removal rates were achieved with both sludge types with acetate and WO liquor supplementation, indicating that WO liquors could achieve excellent rates of nitrate removal. The performance of the WO liquor was attributed to the variety of organic carbon substrates (particularly acetic acid) present within the liquor. PMID:21196117

  5. Microbial lipids and stable foam formation in the activated sludge process.

    PubMed

    Goddard, A J; Forster, C F

    1991-01-01

    The presence of fats and oils in sewage has been related to the formation of stable foams in activated sludge treatment systems. Foam forming microbes can utilise and, in some cases, store lipid substrates. Since surface lipids would confer the hydrophobicity necessary for flotation on the sludge biomass, the extractable lipids in foaming and non-foaming biomass samples were examined. Both pure mono-cultures and sludge samples were used. The results showed that, whilst there were some differences in the lipid profiles of the mono-cultures, the different sludge types did not show any significant pattern or variation which could be used as a lipid-based explanation for foam formation. PMID:1907713

  6. Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge.

    PubMed

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

    2016-01-01

    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. PMID:27508364

  7. Mechanistic model for interpreting the toxic effects of sulfonamides on nitrification.

    PubMed

    Huang, Xiangfeng; Feng, Yi; Hu, Cui; Xiao, Xiaoyu; Yu, Daliang; Zou, Xiaoming

    2016-03-15

    Antibiotics are categorized as pseudopersistent compounds because of their widespread use and continuous emission into the environment. Biological systems such as active sludge and biofilms are still the principal tools used to remove antibiotics in wastewater treatment plants (WWTPs). Consequently, it is important to determine the relationship between toxic effects in biological WWTPs and the structural characteristics of antibiotics. In the present study, toxic effects of 10 sulfonamides (SAs) on nitrification in an active sludge system were studied. The toxicity results (half-effective concentrations, EC50) indicated that the toxicity of sulfadimethoxine (SDM) is approximately 4 times as large as that of sulfadiazine (SD). Based on the toxicity mechanism and the partial least squares regression (PLS) method, an optimum quantitative structure-activity relationship (QSAR) model was developed for the test system. The mechanistic model showed that the pKa, the binding energies between SAs with dihydropteroate synthetase ( [Formula: see text] ) and the binding energies between SAs with ammonia monooxygenase ( [Formula: see text] ) are the key factors affecting the toxic effects of SAs on nitration process in active sludge system, following an order of importance of [Formula: see text] > [Formula: see text] >pKa. PMID:26651069

  8. Effect of pH on phosphorus, copper, and zinc elution from swine wastewater activated sludge.

    PubMed

    Waki, Miyoko; Yasuda, Tomoko; Fukumoto, Yasuyuki; Suzuki, Kazuyoshi

    2014-01-01

    With the goal of reducing the amounts of phosphorus (P), copper (Cu), and zinc (Zn) discharged from swine wastewater activated sludge treatment facilities, we studied the elution of these elements from activated sludge at various pH values. Sludge samples with neutral pH collected from three farms were incubated at pH values ranging from 3 to 10. The soluble concentrations of these elements changed dramatically with pH and were highest at pH 3. We assumed that P present in the sludge under neutral and alkaline conditions was in insoluble form bound up with magnesium (Mg) and calcium (Ca), because Ca and Mg also eluted from the sludge at low pH. To clarify forms of Zn and Cu in the sludge, we performed a sequential extraction analysis. Zinc in adsorbed, organically bound, and sulfide fractions made up a large proportion of the total Zn. Copper in organically bound, carbonate, and sulfide fractions made up a large proportion of the total Cu. The soluble P concentrations were lowest at pH 9 or 10 (11-36 mg/L), the soluble Zn concentrations were lowest at pH 8 or 9 (0.07-0.15 mg/L), and the soluble Cu concentrations were lowest at pH 6-9 (0.2 mg/L, the detection limit). PMID:25116486

  9. Detection of enteric viruses in activated sludge by feasible concentration methods

    PubMed Central

    Prado, Tatiana; Gaspar, Ana Maria Coimbra; Miagostovich, Marize Pereira

    2014-01-01

    Human enteric viruses are responsible to cause several diseases, including gastroenteritis and hepatitis, and can be present in high amounts in sewage sludge. This study compared virus recovery efficiency of two feasible concentration methods used for detecting human adenovirus (HAdV), rotavirus species A (RV-A), norovirus genogroup II (NoV GII) and hepatitis A virus (HAV) in sewage sludge from an activated sludge process. Twelve sewage sludge samples were collected bi-monthly from January to July, 2011. Ultracentrifugation was compared with a simplified protocol based on beef extract elution for recovering enteric viruses. Viruses were quantified by quantitative real-time PCR assays and virus recovery efficiency and limits of detection were determined. Methods showed mean recovery rates lower than 7.5%, presenting critical limits of detection (higher than 102 – 103 genome copies - GC L−1 for all viruses analyzed). Nevertheless, HAdV were detected in 90% of the analyzed sewage sludge samples (range: 1.8 × 104 to 1.1 × 105 GC L−1), followed by RV-A and NoV (both in 50%) and HAV (8%). Results suggesting that activated sludge is contaminated with high viral loads and HAdV are widely disseminated in these samples. The low virus recovery rates achieved, especially for HAV, indicate that other feasible concentration methods could be developed to improve virus recovery efficiency in these environmental matrices. PMID:24948954

  10. A comparative adsorption study: 17β-estradiol onto aerobic granular sludge and activated sludge.

    PubMed

    Zheng, Xiao-ying; He, Yu-jie; Chen, Wei; Wang, Ming-yang; Cao, Su-lan; Ni, Ming; Chen, Yu

    2016-01-01

    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. PMID:26209151

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

    SciTech Connect

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

    2012-01-01

    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.

  12. MiDAS: the field guide to the microbes of activated sludge

    PubMed Central

    McIlroy, Simon Jon; Saunders, Aaron Marc; Albertsen, Mads; Nierychlo, Marta; McIlroy, Bianca; Hansen, Aviaja Anna; Karst, Søren Michael; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2015-01-01

    The Microbial Database for Activated Sludge (MiDAS) field guide is a freely available online resource linking the identity of abundant and process critical microorganisms in activated sludge wastewater treatment systems to available data related to their functional importance. Phenotypic properties of some of these genera are described, but most are known only from sequence data. The MiDAS taxonomy is a manual curation of the SILVA taxonomy that proposes a name for all genus-level taxa observed to be abundant by large-scale 16 S rRNA gene amplicon sequencing of full-scale activated sludge communities. The taxonomy can be used to classify unknown sequences, and the online MiDAS field guide links the identity to the available information about their morphology, diversity, physiology and distribution. The use of a common taxonomy across the field will provide a solid foundation for the study of microbial ecology of the activated sludge process and related treatment processes. The online MiDAS field guide is a collaborative workspace intended to facilitate a better understanding of the ecology of activated sludge and related treatment processes—knowledge that will be an invaluable resource for the optimal design and operation of these systems. Database URL: http://www.midasfieldguide.org PMID:26120139

  13. [Rapid method to extract high-quality RNA from activated sludge].

    PubMed

    Jin, Min; Zhao, Zu-Guo; Qiu, Zhi-Gang; Wang, Jing-Feng; Chen, Zhao-Li; Shen, Zhi-Qiang; Li, Chao; Wang, Xin-Wei; Dong, Yan; Li, Jun-Wen

    2010-01-01

    An effective and fast RNA isolation method of activated sludge was established and five different methods were compared based on RNA yield, purity, integrity, RT-PCR amplification of 16S rRNA genes and subsequent terminal restriction fragment length polymorphism (T-RFLP) analysis. That is, the precipitated activated sludge was washed with TENP and PBS buffer, followed by using lysozyme and TRIzol to direct lysis of microbial cells, chloroform to remove protein and most of the DNA from bacterial lysate, isopropanol to precipitate nucleic acid and DNase I to hydrolyze residual DNA. To further purify RNA, RNA purifying column was utilized. The results demonstrated that the extraction method, with the aid of TRIzol and RNA purification kit, can effectively extract high-quality RNA. It not only means low degradability and high quantity, purity and diversity, but also the genes of 16S rRNA and amoA can be amplified by RT-PCR. Compared with other methods, it showed great advantage of low cost and high efficiency and can be applied to RNA extraction of activated sludge in a large number. Furthermore, T-RFLP results indicated that the community composition as well as the abundance of individual members was affected by the kind of RNA extraction methods. This work established a rapid and effective method to extract high-quality RNA from activated sludge and would show great potential for monitoring microbial changes and studying metabolism and community array of activated sludge. PMID:20329549

  14. MiDAS: the field guide to the microbes of activated sludge.

    PubMed

    McIlroy, Simon Jon; Saunders, Aaron Marc; Albertsen, Mads; Nierychlo, Marta; McIlroy, Bianca; Hansen, Aviaja Anna; Karst, Søren Michael; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2015-01-01

    The Microbial Database for Activated Sludge (MiDAS) field guide is a freely available online resource linking the identity of abundant and process critical microorganisms in activated sludge wastewater treatment systems to available data related to their functional importance. Phenotypic properties of some of these genera are described, but most are known only from sequence data. The MiDAS taxonomy is a manual curation of the SILVA taxonomy that proposes a name for all genus-level taxa observed to be abundant by large-scale 16 S rRNA gene amplicon sequencing of full-scale activated sludge communities. The taxonomy can be used to classify unknown sequences, and the online MiDAS field guide links the identity to the available information about their morphology, diversity, physiology and distribution. The use of a common taxonomy across the field will provide a solid foundation for the study of microbial ecology of the activated sludge process and related treatment processes. The online MiDAS field guide is a collaborative workspace intended to facilitate a better understanding of the ecology of activated sludge and related treatment processes--knowledge that will be an invaluable resource for the optimal design and operation of these systems. PMID:26120139

  15. Removal of endocrine-disrupting chemicals in activated sludge treatment works.

    PubMed

    Johnson, A C; Sumpter, J P

    2001-12-15

    The release of endocrine-disrupting chemicals into the aquatic environment has raised the awareness of the central role played by sewage treatment in lowland water quality. This review focuses on the activated sludge process, which is commonly used to treat sewage in large towns and cities and which successfully removes the bulk of the organic compounds that enter the works. However, not all compounds are completely broken down or converted to biomass. For example, the estrogenic alkylphenols and steroid estrogens found in effluent are the breakdown products of incomplete breakdown of their respective parent compounds. Batch microcosm studies have indicated that estrone, ethinylestradiol, and alkylphenols will not be completely eliminated in activated sludge over typical treatment times. Field data suggest that the activated sludge treatment process can consistently remove over 85% of estradiol, estriol, and ethinylestradiol. The removal performance for estrone appears to be less and is more variable. Because of its relatively high hydrophobicity, the accumulation of alkylphenol in sludge has been observed. Although it has not been examined, accumulation of ethinylestradiol in sludge is a possibility due to its recalcitrance and hydrophobicity. A comparison between the concentrations of some of the major endocrine-active chemicals in effluents and their biological potencies has been made, to direct attention to the chemicals of most concern. While water purification techniques such as UV or activated charcoal could significantly remove these microorganic contaminants, the high costs involved suggest that research into the potential for treatment optimization should receive more attention. PMID:11775141

  16. Study of kinetics of degradation of cyclohexane carboxylic acid by acclimated activated sludge.

    PubMed

    Wang, Chunhua; Shi, Shuian; Chen, Hongyan

    2016-01-01

    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. PMID:27191578

  17. Aerobic composting of waste activated sludge: Kinetic analysis for microbiological reaction and oxygen consumption

    SciTech Connect

    Yamada, Y.; Kawase, Y. . E-mail: bckawase@mail.eng.toyo.ac.jp

    2006-07-01

    In order to examine the optimal design and operating parameters, kinetics for microbiological reaction and oxygen consumption in composting of waste activated sludge were quantitatively examined. A series of experiments was conducted to discuss the optimal operating parameters for aerobic composting of waste activated sludge obtained from Kawagoe City Wastewater Treatment Plant (Saitama, Japan) using 4 and 20 L laboratory scale bioreactors. Aeration rate, compositions of compost mixture and height of compost pile were investigated as main design and operating parameters. The optimal aerobic composting of waste activated sludge was found at the aeration rate of 2.0 L/min/kg (initial composting mixture dry weight). A compost pile up to 0.5 m could be operated effectively. A simple model for composting of waste activated sludge in a composting reactor was developed by assuming that a solid phase of compost mixture is well mixed and the kinetics for microbiological reaction is represented by a Monod-type equation. The model predictions could fit the experimental data for decomposition of waste activated sludge with an average deviation of 2.14%. Oxygen consumption during composting was also examined using a simplified model in which the oxygen consumption was represented by a Monod-type equation and the axial distribution of oxygen concentration in the composting pile was described by a plug-flow model. The predictions could satisfactorily simulate the experiment results for the average maximum oxygen consumption rate during aerobic composting with an average deviation of 7.4%.

  18. Biocrude production by activated sludge microbial cultures using pulp and paper wastewaters as fermentation substrate.

    PubMed

    Upadhyaya, Kamal Lamichhane; Mondala, Andro; Hernandez, Rafael; French, Todd; Green, Magan; McFarland, Linda; Holmes, William

    2013-01-01

    Municipal wastewater activated sludge contains a mixed microbial community, which can be manipulated to produce biocrude, a lipid feedstock for biodiesel production. In this study, the potential of biocrude production by activated sludge microorganisms grown in three different types of pulp and paper mill wastewaters was investigated. A 20% (v/v) activated sludge was inoculated into pulp and paper wastewater, supplemented with glucose (60 g/L) and nutrients (nitrogen and phosphorus) to obtain a high carbon to nitrogen ratio (70:1). The culture was incubated aerobically for seven days. The results showed that the activated sludge microorganisms were able to grow and accumulate lipids when cultivated in amended wastewaters. Microorganisms growing in anaerobic settling pond effluent water showed the highest lipid accumulation of up to 40.6% cell dry weight (CDW) after five days of cultivation compared with pulp wash wastewater (PuWW) (11.7% CDW) and mixed wastewater (MWW) (8.2% CDW) after seven days of cultivation. The lipids mostly contained C16-C18 fatty acids groups with oleic acid and palmitic acid being the dominant fatty acids. The maximum biodiesel yield was about 6-8% CDW for all the wastewaters. The results showed the potential of utilizing pulp and paper mill effluents and other waste streams, such as activated sludge for the sustainable production of lipids for biofuel production. PMID:24350471

  19. Effect of polyhydroxyalkanoates on dark fermentative hydrogen production from waste activated sludge.

    PubMed

    Wang, Dongbo; Zeng, Guangming; Chen, Yinguang; Li, Xiaoming

    2015-04-15

    Polyhydroxyalkanoates (PHA), an intracellular energy and carbon storage polymer, can be accumulated in activated sludge in substantial quantities under wastewater dynamic treatment (i.e., substrate feast-famine) conditions. However, its influence on hydrogen production has never been investigated before. This study therefore evaluated the influences of PHA level and composition in waste activated sludge (WAS) on hydrogen production. The results showed that with the increase of sludge PHA content from 25 to 178 mg per gram volatile suspended solids (VSS) hydrogen production from WAS alkaline anaerobic fermentation increased from 26.5 to 58.7 mL/g VSS. The composition of PHA was also found to affect hydrogen production. When the dominant composition shifted from polyhydroxybutyrate (PHB) to polyhydroxyvalerate (PHV), the amount of generated hydrogen decreased from 51.2 to 41.1 mL/g VSS even under the same PHA level (around 130 mg/g VSS). The mechanism studies exhibited that the increased PHA content accelerated both the cell solubilization and the hydrolysis process of solubilized substrates. Compared with the PHB-dominant sludge, the increased PHV fraction not only slowed the hydrolysis process but also caused more propionic acid production, with less theoretical hydrogen generation in this fermentation type. It was also found that the increased PHA content enhanced the soluble protein conversion of non-PHA biomass. Further investigations with enzyme analyses showed that both the key hydrolytic enzyme activities and hydrogen-forming enzyme activities were in the sequence of the PHB-dominant sludge > the PHV-dominant sludge > the low PHA sludge, which was in accord with the observed order of hydrogen yield. PMID:25697693

  20. Organic matter extracted from activated sludge with ammonium hydroxide and its characterization.

    PubMed

    Wei, Liangliang; Wang, Kun; Zhao, Qingliang; Jiang, Junqiu; Xie, Chunmei; Qiu, Wei

    2010-01-01

    In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant, organic matter within sludge was extracted with NH3.H20 preferentially, and subsequently fractionated into five fractions using XAD-8/XAD-4 resins. Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH3.H2O. Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter (accounting for 32.2% and 48.0% of the bulk organic matter, respectively), whereas transphilic acid, hydrophobic neutral and transphilic neutral were quite low (accounting for 9.2%, 5.8% and 4.8%, respectively). Despite that the extractant of NH3.H2O showed a relatively higher extraction efficiency of the aromatic components, the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted, especially for neutral and hydrophilic fractions. In addition, acidic fractions contained more aromatic humic-like components, whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components. Extraction of sludge organics with NH3.H2O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics. PMID:20608497

  1. Chitosan use in chemical conditioning for dewatering municipal-activated sludge.

    PubMed

    Zemmouri, H; Mameri, N; Lounici, H

    2015-01-01

    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. PMID:25812088

  2. The Impact of Oxone on Disintegration and Dewaterability of Waste Activated Sludge.

    PubMed

    Wacławek, Stanisław; Grübel, Klaudiusz; Chłąd, Zuzanna; Dudziak, Mariusz; Černík, Miroslav

    2016-02-01

    Biochemical parameters such as soluble chemical oxygen demand (SCOD), phosphate, ammonium nitrogen and proteins are often used to characterize the efficiency of disintegration of waste activated sludge (WAS) flocs and microorganism cells. In this study, the chemical disintegration using peroxymonosulfate (MPS, Oxone) and thermally activated MPS, were evaluated for the destruction of WAS. Our study was conducted for chemical disintegration of WAS by MPS in doses between 84.7 - 847.5 mg/g(TS) activated by temperatures of 50, 70 and 90 °C over 30 minutes. The application of these methods causes an increase in the soluble COD value and protein concentration in the supernatant. Also, they positively influence the sludge volume index (SVI) which decreased from 89.8 to 17.2 ml/g. Our research work confirmed that the application of thermally activated MPS may become a new effective way of improving sewage treatment and sewage sludge processing. PMID:26803102

  3. Simulated Distribution Nitrification: Nitrification Index Evaluation and Viable AOB

    EPA Science Inventory

    Lab-scale reactors evaluated the impact of increasing temporal influent monochloramine (NH2Cl) concentrations (0.0 to 3.2 mg Cl2 L-1) and chlorine to nitrogen mass ratios (0:1 to 3.2:1) on nitrification, allowing evaluation of the recently proposed nitrification index (NI) for ch...

  4. Rhodoligotrophos jinshengii sp. nov., isolated from activated sludge.

    PubMed

    Deng, Shi-Kai; Chen, Guo-Qiang; Chen, Qing; Cai, Shu; Yao, Li; He, Jian; Li, Shun-Peng

    2014-09-01

    A Gram-stain-negative, non-spore-forming, non-motile, ovoid, aerobic bacterial strain, designated BUT-3(T), was isolated from activated sludge from the wastewater treatment facility of a herbicide-manufacturing plant in Kunshan city, Jiangsu province, PR China. Strain BUT-3(T) grew between 15 and 40 °C, with optimum growth at 30 °C. The pH range for growth was between 5.0 and 10.0 (optimum pH 7.0). The range of NaCl concentrations for growth of strain BUT-3(T) was 0-7.0 % (w/v), with an optimum of 1.5-3.0 % (w/v). A phylogenetic tree based on 16S rRNA gene sequence analysis showed that strain BUT-3(T) clustered closely with Rhodoligotrophos appendicifer 120-1(T) (98.32 % similarity), with a bootstrap confidence level of 100 %. The major fatty acids (>5 % of total fatty acids) were C19 : 0 cyclo ω8c, C18 : 1ω7c, C16 : 0, anteiso-C15 : 0 and iso-C15 : 0. Strain BUT-3(T) contained ubiquinone Q-10 as the predominant respiratory quinone. The polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, three unidentified aminolipids (AL1-3), two unknown phospholipids (PL1, 5), four unidentified glycolipids (GL1-4) and two unknown lipids (L1, 2). The G+C content of the genomic DNA was 67.7 mol%. The DNA-DNA relatedness between BUT-3(T) and R. appendicifer 120-1(T) was 44.1±0.6 %. Based on the polyphasic taxonomic data, strain BUT-3(T) should be classified as a representative of a novel species of the genus Rhodoligotrophos, for which the name Rhodoligotrophos jinshengii sp. nov. is proposed. The type strain is BUT-3(T) ( = CCTCC AB2013083(T) = KACC 17220(T)). PMID:25002364

  5. Steady-state analysis of activated sludge processes with a settler model including sludge compression.

    PubMed

    Diehl, S; Zambrano, J; Carlsson, B

    2016-01-01

    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. PMID:26476681

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

    PubMed Central

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

    2016-01-01

    Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology. PMID:26830464

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

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

    PubMed

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

    2016-01-01

    Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology. PMID:26830464

  9. Effect of magnetic nanoparticles on the performance of activated sludge treatment system.

    PubMed

    Ni, Shou-Qing; Ni, Jianyuan; Yang, Ning; Wang, Juan

    2013-09-01

    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. PMID:23835260

  10. Use of metagenomic approaches to isolate lipolytic genes from activated sludge.

    PubMed

    Liaw, Ren-Bao; Cheng, Mei-Ping; Wu, Ming-Che; Lee, Chia-Yin

    2010-11-01

    The aims of this study were to access the bacterial diversity and isolate lipolytic genes using the metagenomic approach in activated sludge of a swine wastewater treatment facility. On the basis of BLASTN analysis of 16S rRNA gene clones, most of these communities (90%) were of uncultivated bacteria. The metagenomic library was constructed using a plasmid vector and DNA extracted directly from activated sludge samples. The average insert size was approximately 5.1 kb. A total of 12 unique and lipolytic clones were obtained using the tributyrin plate assay. The rate of discovering a lipolytic clone in this study was as high as 0.31%. Molecular analysis revealed that most of the 16 putative lipolytic enzymes showed 28-55% identity with non-redundant protein sequences in the database. Briefly, this study demonstrates that activated sludge is an ideal bioresource for isolating new lipolytic enzymes. PMID:20639117

  11. Prediction of the effect of fine grit on the MLVSS/MLSS ratio of activated sludge.

    PubMed

    Fan, Jianping; Ji, Fangying; Xu, Xiaoyi; Wang, Ying; Yan, Dachao; Xu, Xuan; Chen, Qingkong; Xiong, Jingzhong; He, Qiang

    2015-08-01

    This paper investigated the suspension properties of fine grit with different particle sizes in a bioreactor and developed a model to predict its effect on the ratio of mixed liquor volatile suspended solids to the mixed liquor suspended solids (MLVSS/MLSS) of activated sludge. The experimental results revealed that a smaller particle size corresponds to a larger suspension ratio, defined as the proportion of fine grit brought in by influent that is suspended in the activated sludge, and a smaller MLVSS/MLSS ratio. The model demonstrated that the effect of fine grit on the MLVSS/MLSS ratio is related to the fine grit concentration and chemical oxygen demand in influent and the observed sludge yield. However, fine grit has no influence on the activity of microorganisms. Wastewater treatment plants (WWTPs) can adjust MLSS based on the MLVSS/MLSS ratio to ensure the stability of MLVSS, which can achieve the stable operation of WWTPs. PMID:25919937

  12. Effect of a static magnetic field on formaldehyde biodegradation in wastewater by activated sludge.

    PubMed

    Łebkowska, Maria; Rutkowska-Narożniak, Anna; Pajor, Elżbieta; Pochanke, Zbigniew

    2011-10-01

    The aim of this study was to determine the impact of a static magnetic field (MF) of 7 mT on formaldehyde (FA) biodegradation by activated sludge in synthetic wastewater. The MF had a positive effect on activated sludge biomass growth and dehydrogenase activity. The influence of the MF on the degradation process was observed with a FA concentration of 2400-2880 mg/l. Decreases in FA concentration and chemical oxygen demand (COD) were greater, by 30% and 26% respectively, than those in the control sample. At initial FA concentrations in raw wastewater of 2400 and 2880 mg/l, a decrease in the wastewater biodegradation efficiency was observed. This resulted in an increase of the ecotoxicity of the effluent to Daphnia magna. The value of the sludge biotic index (SBI) was dependent on the FA concentration in raw wastewater and the induction of the MF. PMID:21824771

  13. Effect of membrane bioreactor configurations on sludge structure and microbial activity.

    PubMed

    Clouzot, L; Roche, N; Marrot, B

    2011-01-01

    The aim of this paper was to determine the effect of two different membrane bioreactor (MBR) configurations (external/immersed) on sludge structure and microbial activity. Sludge structure was deduced from rheological measurements. The high shear stress induced by the recirculation pump in the external MBR was shown to result in decreasing viscosity due to activated sludge (AS) deflocculation. Besides, soluble microbial products (SMP) release was higher in the external MBR (5 mgCOD gMLVSS(-1)) than in the immersed configuration (2 mgCOD gMLVSS(-1)). Microbial activity was followed from respirometry tests by focusing on the distinction between heterotrophs and autotrophs. An easier autotrophic microbe development was then observed in the immersed MBR compared to the external one. However, the external MBR was shown to allow better heterotrophic microbe development. PMID:20947340

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

    PubMed

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

    2014-01-01

    A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus concentration in batch tests and in a municipal full-scale WWTP under steady-state and dynamic conditions. The experimental and modeling results suggest that both adsorption and inactivation processes, modeled as reversible first-order reactions, contribute to virus elimination in activated sludge systems. The model should be a useful tool to estimate the number of viruses entering water bodies from the discharge of treated effluents. PMID:25259502

  15. Fatty acids of lipid fractions in extracellular polymeric substances of activated sludge flocs.

    PubMed

    Conrad, Arnaud; Suutari, Merja Kontro; Keinänen, Minna M; Cadoret, Aurore; Faure, Pierre; Mansuy-Huault, Laurence; Block, Jean-Claude

    2003-10-01

    Phospholipid (PL), glycolipid (GL), and neutral lipid (NL) FA, and the lipopolysaccharide 2- and 3-hydroxy (LPS 2-OH and 3-OH) FA of activated sludges and extracted extracellular polymeric substances (EPS) were determined on samples collected from two wastewater treatment plants. EPS extracted from sludges by means of sonication and cation exchange contained proteins (43.4%), humic-like substances (11.5%), nucleic acids (10.9%), carbohydrates (9.9%), and lipid-bound FA (1.8%). The lipids associated with EPS were composed of GL, PL, NL, and LPS acids in proportions of 61, 21, 16, and 2%, respectively. The profiles of lipid-bound FA in activated sludges and EPS were similar (around 85 separate FA were identified). The FA signatures observed can be attributed to the likely presence of yeasts, fungi, sulfate-reducing bacteria, gram-positive and gram-negative bacteria, and, in lesser quantities, mycobacteria. Comparison of data from the dates of sampling (January and September) showed that there were more unsaturated PLFA in the EPS extracted from the activated sludges sampled in January. This observation could be partly related to microorganism adaptation to temperature variations. The comparison between two wastewater treatment plants showed that the FA profiles were similar, although differences in microbial community structure were also seen. Most of the FA in sludges had an even number of carbons. PMID:14669975

  16. Micropollutant removal by attached and suspended growth in a hybrid biofilm-activated sludge process.

    PubMed

    Falås, P; Longrée, P; la Cour Jansen, J; Siegrist, H; Hollender, J; Joss, A

    2013-09-01

    Removal of organic micropollutants in a hybrid biofilm-activated sludge process was investigated through batch experiments, modeling, and full-scale measurements. Batch experiments with carriers and activated sludge from the same full-scale reactor were performed to assess the micropollutant removal rates of the carrier biofilm under oxic conditions and the sludge under oxic and anoxic conditions. Clear differences in the micropollutant removal kinetics of the attached and suspended growth were demonstrated, often with considerably higher removal rates for the biofilm compared to the sludge. For several micropollutants, the removal rates were also affected by the redox conditions, i.e. oxic and anoxic. Removal rates obtained from the batch experiments were used to model the micropollutant removal in the full-scale process. The results from the model and plant measurements showed that the removal efficiency of the process can be predicted with acceptable accuracy (± 25%) for most of the modeled micropollutants. Furthermore, the model estimations indicate that the attached growth in hybrid biofilm-activated sludge processes can contribute significantly to the removal of individual compounds, such as diclofenac. PMID:23764599

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

    PubMed

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

    2016-06-01

    In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production. PMID:26698921

  18. [Comparative Metagenomics of BIOLAK and A2O Activated Sludge Based on Next-generation Sequencing Technology].

    PubMed

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

    2016-02-15

    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. PMID:27363155

  19. Comparison of microbial communities of activated sludge and membrane biofilm in 10 full-scale membrane bioreactors.

    PubMed

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

    2016-09-15

    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). Between the biofilm and activated sludge, community composition made significant difference, but its diversity measures (i.e., alpha diversity, e.g., richness, diversity and evenness) did not (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. PMID:27262549

  20. Effects of black liquor shocks on activated sludge treatment of bleached kraft pulp mill wastewater.

    PubMed

    Morales, Gabriela; Pesante, Silvana; Vidal, Gladys

    2015-01-01

    Kraft pulp mills use activated sludge systems to remove organic matter from effluents. Process streams may appear as toxic spills in treatment plant effluents, such as black liquor, which is toxic to microorganisms of the activated sludge. The present study evaluates the effects of black liquor shocks in activated sludge systems. Four black liquor shocks from 883 to 3,225 mg chemical oxygen demand-COD L(-1) were applied during 24 hours in a continuously operating lab-scale activated sludge system. Removal efficiencies of COD, color and specific compounds were determined. Moreover, specific oxygen uptake rate (SOUR), sludge volumetric index (SVI) and indicator microorganisms were evaluated. Results show that the addition of black liquor caused an increase in COD removal (76-67%) immediately post shock; followed two days later by a decrease (-19-50%). On the other hand, SOUR ranged between 0.152 and 0.336 mgO2 g(-1) volatile suspended solids-VSS• min(-1) during shocks, but the initial value was reestablished at hour 24. When the COD concentration of the shock was higher than 1,014 mg/L, the abundance of stalked ciliates and rotifers dropped. Finally, no changes in SVI were observed, with values remaining in the range 65.8-40.2 mL g(-1) total suspended solids-TSS during the entire operating process. Based on the results, the principal conclusion is that the activated sludge system with the biomass adapted to the kraft pulp effluent could resist a black liquor shock with 3,225 mgCOD L(-1) of concentration during 24 h, under this study's conditions. PMID:25837566

  1. Relationship of species-specific filament levels to filamentous bulking in activated sludge.

    PubMed

    Liao, Jiangying; Lou, Inchio; de los Reyes, Francis L

    2004-04-01

    To examine the relationship between activated-sludge bulking and levels of specific filamentous bacteria, we developed a statistics-based quantification method for estimating the biomass levels of specific filaments using 16S rRNA-targeted fluorescent in situ hybridization (FISH) probes. The results of quantitative FISH for the filament Sphaerotilus natans were similar to the results of quantitative membrane hybridization in a sample from a full-scale wastewater treatment plant. Laboratory-scale reactors were operated under different flow conditions to develop bulking and nonbulking sludge and were bioaugmented with S. natans cells to stimulate bulking. Instead of S. natans, the filament Eikelboom type 1851 became dominant in the reactors. Levels of type 1851 filaments extending out of the flocs correlated strongly with the sludge volume index, and extended filament lengths of approximately 6 x 10(8) micro m ml(-1) resulted in bulking in laboratory-scale and full-scale activated-sludge samples. Quantitative FISH showed that high levels of filaments occurred inside the flocs in nonbulking sludge, supporting the "substrate diffusion limitation" hypothesis for bulking. The approach will allow the monitoring of incremental improvements in bulking control methods and the delineation of the operational conditions that lead to bulking due to specific filaments. PMID:15066840

  2. Degradation of PPCPs in activated sludge from different WWTPs in Denmark.

    PubMed

    Chen, Xijuan; Vollertsen, Jes; Nielsen, Jeppe Lund; Dall, Agnieszka Gieraltowska; Bester, Kai

    2015-12-01

    Pharmaceuticals and Personal care products (PPCPs) are often found in effluents from wastewater treatment plants (WWTPs) due to insufficient removal during wastewater treatment processes. To understand the factors affecting the removal of PPCPs in classical activated sludge WWTPs, the present study 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 and Carbamazepine were found to be persistent in the systems. Degradation rate constants were calculated as 0.0026-0.0407 for NSAID pharmaceuticals and 0.0022-0.0065 for triclosan. No relationships were observed between degradation rates and biomass concentrations in the diverse sludges. However, for the investigated PPCPs, the optimal SRT was within 14-20 days (for these values degradation of these PPCPs was the most efficient). Though all of these parameters influence the degradation rate, none of them seems to be overall decisive. These observations indicate that the biological composition of the sludge is more important than the design parameters of the respective treatment plant. PMID:26407712

  3. The abundance and diversity of ammonia-oxidizing bacteria in activated sludge under autotrophic domestication.

    PubMed

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

    2013-04-01

    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. PMID:24620598

  4. Proposal for a screening test to evaluate the fate of organic micropollutants in activated sludge.

    PubMed

    Salvetti, Roberta; Vismara, Renato; Dal Ben, Ilaria; Gorla, Elena; Romele, Laura

    2011-04-01

    The concentrations of organic micropollutants are usually low in wastewaters (order of magnitude of mg L(-1)). However, their emission standards, especially in the case of carcinogenic and bioaccumulating substances, are often much lower (order of magnitude of microg L(-1)). Since these substances, in some cases, can be adsorbable or volatile, their removal via volatilization, biodegradation or sludge adsorption in a wastewater treatment plant (WWTP) becomes a significant feature to include in the usual design process, in order to verify the emission standards in gas and sludge too. In this study a simple screening batch test for the evaluation of the fate of organic micropollutants in water, air and sludge is presented. The test is set up by means of simple laboratory instruments and simulates an activated sludge tank process. In this study the results obtained for four substances with different chemical properties (i.e. toluene, benz(a)anthracene, phenol and benzene) are presented. The screening test proposed can be a useful tool to assess in about one month the fate of organic micropollutants in an activated sludge tank of a WWTP. Moreover, the test can constitute a useful support in the use of mathematical models, since it allows the verification of model results and the calibration of the reactions involved in the removal process. PMID:21877546

  5. Comparison of Simultaneous Nitrification and Denitrification for Three Different Reactors

    PubMed Central

    Khanitchaidecha, W.; Nakaruk, A.; Koshy, P.; Futaba, K.

    2015-01-01

    Discharge of high NH4-N containing wastewater into water bodies has become a critical and serious issue due to its negative impact on water and environmental quality. In this research, the performance of three different reactors was assessed and compared with regard to the removal of NH4-N from wastewater. The highest nitrogen removal efficiency of 98.3% was found when the entrapped sludge reactor (ESR), in which the sludge was entrapped in polyethylene glycol polymer, was used. Under intermittent aeration, nitrification and denitrification occurred simultaneously in the aerobic and anaerobic periods. Moreover, internal carbon was consumed efficiently for denitrification. On the other hand, internal carbon consumption was not found to occur in the suspended sludge reactor (SSR) and the mixed sludge reactor (MSR) and this resulted in nitrogen removal efficiencies of SSR and MSR being 64.7 and 45.1%, respectively. Nitrification and denitrification were the main nitrogen removal processes in the aerobic and anaerobic periods, respectively. However, due to the absence of sufficient organic carbon, denitrification was uncompleted resulting in high NO3-N contents in the effluent. PMID:26380304

  6. A laboratory-scale test of anaerobic digestion and methane production after phosphorus recovery from waste activated sludge.

    PubMed

    Takiguchi, Noboru; Kishino, Machiko; Kuroda, Akio; Kato, Junichi; Ohtake, Hisao

    2004-01-01

    In enhanced biological phosphorus removal (EBPR) processes, activated sludge microorganisms accumulate large quantities of polyphosphate (polyP) intracellularly. We previously discovered that nearly all of polyP could be released from waste activated sludge simply by heating it at 70 degrees C for about 1 h. We also demonstrated that this simple method was applicable to phosphorus (P) recovery from waste activated sludge in a pilot plant-scale EBPR process. In the present study, we evaluated the effect of this sludge processing (heat treatment followed by calcium phosphate precipitation) on anaerobic digestion in laboratory-scale experiments. The results suggested that the sludge processing for P recovery could improve digestive efficiency and methane productivity at both mesophilic (37 degrees C) and thermophilic (53 degrees C) temperatures. In addition, heat-treated waste sludge released far less P into the digested sludge liquor than did untreated waste sludge. It is likely that the P recovery step prior to anaerobic digestion has a potential advantage for controlling struvite (magnesium ammonium phosphate) deposit problems in sludge handling processes. PMID:16233643

  7. A New Developed Airlift Reactor Integrated Settling Process and Its Application for Simultaneous Nitrification and Denitrification Nitrogen Removal

    PubMed Central

    Zhang, Tao; Wei, Chaohai

    2013-01-01

    This study presented the performance of simultaneous nitrification and denitrification (SND) process using a new developed hybrid airlift reactor which integrated the activated sludge reaction process in the airlift reactor and the sludge settling separation process in the clarifier. The proposed reactor was started up successfully after 76 days within which the COD and total nitrogen removal rate can reach over 90% and 76.3%, respectively. The effects of different COD/N and DO concentrations on the performance of reactor were investigated. It was found that the influent COD/N maintained at 10 was sufficient for SND and the optimum DO concentration for SND was in the range of 0.5 to 0.8 mg L−1. Batch test demonstrated that both macroscopic environment caused by the spatial DO concentration difference and microscopic environment caused by the stratification of activated sludge may be responsible for the SND process in the reactor. The hybrid airlift reactor can accomplish SND process in a single reactor and in situ automatic separation of sludge; therefore, it may serve as a promising reactor in COD and nitrogen removal fields. PMID:23935415

  8. A new developed airlift reactor integrated settling process and its application for simultaneous nitrification and denitrification nitrogen removal.

    PubMed

    Zhang, Tao; Wei, Chaohai

    2013-01-01

    This study presented the performance of simultaneous nitrification and denitrification (SND) process using a new developed hybrid airlift reactor which integrated the activated sludge reaction process in the airlift reactor and the sludge settling separation process in the clarifier. The proposed reactor was started up successfully after 76 days within which the COD and total nitrogen removal rate can reach over 90% and 76.3%, respectively. The effects of different COD/N and DO concentrations on the performance of reactor were investigated. It was found that the influent COD/N maintained at 10 was sufficient for SND and the optimum DO concentration for SND was in the range of 0.5 to 0.8 mg L(-1). Batch test demonstrated that both macroscopic environment caused by the spatial DO concentration difference and microscopic environment caused by the stratification of activated sludge may be responsible for the SND process in the reactor. The hybrid airlift reactor can accomplish SND process in a single reactor and in situ automatic separation of sludge; therefore, it may serve as a promising reactor in COD and nitrogen removal fields. PMID:23935415

  9. Response of activated sludge to the treatment of oxytetracycline production waste stream.

    PubMed

    Liu, Miaomiao; Zhang, Yu; Ding, Ran; Gao, Yingxin; Yang, Min

    2013-10-01

    To investigate how the microbial community in activated sludge responded to high antibiotic levels, a bench-scale aerobic wastewater treatment system was used to treat oxytetracycline (OTC) mother liquor (OTC-ML). Removal efficiency of chemical oxygen demand decreased from 64.9 to 51.0 % when the OTC level increased from 191.6 to 620.5 mg/L, respectively. According to the cloning results, Psychrobacter and Cryptophyta were the dominant bacterium and eukaryote in the inoculated sludge, respectively, both of which related to low temperature. After OTC exposure, Alphaproteobacteria and Betaproteobacteria became the dominant bacteria, with a small proportion of Firmicutes, Actinobacteria appeared, and fungi (mainly Saccharomycotina) became the dominant eukaryotes, indicating the possible functions of these microorganisms in the wastewater treatment of OTC-ML. The relative abundance of nine tetracycline resistance genes and four mobile elements (class 1 integron, class 2 integron, transposon Tn916/1545, and pattern 1 insertion sequence common region) significantly increased from undetectable to 2.1 × 10(-3) in the inoculated sludge to 1.7 × 10(-4)-9.8 × 10(-1) in sludge exposed to 620.5 mg/L OTC by using real-time PCR. The variety of gene cassette arrays of class 1 integron in the sludge samples increased with increasing OTC exposure concentration. PMID:23188460

  10. Ammonia-methane two-stage anaerobic digestion of dehydrated waste-activated sludge.

    PubMed

    Nakashimada, Yutaka; Ohshima, Yasutaka; Minami, Hisao; Yabu, Hironori; Namba, Yuzaburo; Nishio, Naomichi

    2008-07-01

    The study investigated methane production from dehydrated waste-activated sludge (DWAS) with approximately 80% water content under thermophilic conditions. The repeated batch-wise treatment of DWAS using methanogenic sludge unacclimated to high concentrations of ammonia, increased the ammonia production up to 7,600 mg N per kilogram total wet sludge of total ammonia concentration, and stopped the methane production. Investigation revealed that the loading ratio of DWAS for methanogenic sludge influences anaerobic digestion. Methane production significantly decreased and ammonia concentration increased with the increase in loading ratio of DWAS. Since the semicontinuous culture revealed that approximately 50% of organic nitrogen in DWAS converted to ammonia at sludge retention time (SRT) after 4 days at 37 degrees C and 1.33 days at 55 degrees C, the previous stripping of the ammonia produced from DWAS was carried out. The stripping of ammonia increased methane production significantly. This ammonia-methane two-stage anaerobic digestion demonstrated a successful methane production at SRT 20 days in the semicontinuous operation using a laboratory-scale reactor system. PMID:18491038

  11. Enhancement of aerobic biodegradability potential of municipal waste activated sludge by ultrasonic aided bacterial disintegration.

    PubMed

    Kavitha, S; Jessin Brindha, G M; Sally Gloriana, A; Rajashankar, K; Yeom, Ick Tae; Rajesh Banu, J

    2016-01-01

    An investigation was performed to study the influence of ultrasonic aided bacterial disintegration on the aerobic degradability of sludge. In first phase of the study, effective floc disruption was achieved at an ultrasonic specific energy input of 2.45kJ/kg TS with 44.5mg/L of Extracellular Polymeric Substance (EPS) release including 0.035U/mL and 0.025U/mL protease and amylase activity respectively. In second phase, experimental outcomes revealed bacterial disintegration of floc disrupted-sludge showing a maximum solubilization of about 23% and was observed to be superior to bacterially disintegrated (11%) and control (6%), respectively. The result of aerobic biodegradability of ultrasonic aided bacterially pretreated sludge showed volatile solids (VS) degradation of about 40.2%. The kinetic study of aerobic biodegradability through non linear regression modelling reveals that floc disrupted sludge showed better biodegradability with decay constant of about 0.19d(-1) relatively higher than the control (0.14d(-1)) and bacterially disintegrated (0.17d(-1)) sludges. PMID:26479431

  12. Identification of Triclosan-O-Sulfate and other transformation products of Triclosan formed by activated sludge.

    PubMed

    Chen, Xijuan; Casas, Mònica Escolà; Nielsen, Jeppe Lund; Wimmer, Reinhard; Bester, Kai

    2015-02-01

    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. PMID:25306094

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

    PubMed

    Mokhtarani, Nader; Ganjidoust, Hossein; Vasheghani Farahani, Ebrahim

    2012-01-01

    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. PMID:23369512

  14. FULL-SCALE DEMONSTRATION OF OPEN TANK OXYGEN ACTIVATED SLUDGE TREATMENT

    EPA Science Inventory

    This report presents an operating summary of a full-scale demonstration of the FMC open tank pure oxygen (FMC O2) activated sludge system, conducted at the facilities of the Metropolitan Denver Sewage Disposal District No. 1 (Metro) in Denver, Colorado. The system was operated ov...

  15. Bioremediation of heavy metal-contaminated effluent using optimized activated sludge bacteria

    NASA Astrophysics Data System (ADS)

    Bestawy, Ebtesam El.; Helmy, Shacker; Hussien, Hany; Fahmy, Mohamed; Amer, Ranya

    2013-03-01

    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.

  16. Local adaptive approach toward segmentation of microscopic images of activated sludge flocs

    NASA Astrophysics Data System (ADS)

    Khan, Muhammad Burhan; Nisar, Humaira; Ng, Choon Aun; Lo, Po Kim; Yap, Vooi Voon

    2015-11-01

    Activated sludge process is a widely used method to treat domestic and industrial effluents. The conditions of activated sludge wastewater treatment plant (AS-WWTP) are related to the morphological properties of flocs (microbial aggregates) and filaments, and are required to be monitored for normal operation of the plant. Image processing and analysis is a potential time-efficient monitoring tool for AS-WWTPs. Local adaptive segmentation algorithms are proposed for bright-field microscopic images of activated sludge flocs. Two basic modules are suggested for Otsu thresholding-based local adaptive algorithms with irregular illumination compensation. The performance of the algorithms has been compared with state-of-the-art local adaptive algorithms of Sauvola, Bradley, Feng, and c-mean. The comparisons are done using a number of region- and nonregion-based metrics at different microscopic magnifications and quantification of flocs. The performance metrics show that the proposed algorithms performed better and, in some cases, were comparable to the state-of the-art algorithms. The performance metrics were also assessed subjectively for their suitability for segmentations of activated sludge images. The region-based metrics such as false negative ratio, sensitivity, and negative predictive value gave inconsistent results as compared to other segmentation assessment metrics.

  17. CRITICAL LITERATURE REVIEW AND RESEARCH NEEDED ON ACTIVATED SLUDGE SECONDARY CLARIFIERS

    EPA Science Inventory

    Secondary clarifiers are key to the successful performance of the activated sludge process. They serve to separate out the biological solids and produce a clear effluent and to concentrate the settled solids for return to the aeration basins. Clarifiers have served the purpose fo...

  18. Operational Control Procedures for the Activated Sludge Process, Part III-A: Calculation Procedures.

    ERIC Educational Resources Information Center

    West, Alfred W.

    This is the second in a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. This document deals exclusively with the calculation procedures, including simplified mixing formulas, aeration tank…

  19. Operational Control Procedures for the Activated Sludge Process, Part I - Observations, Part II - Control Tests.

    ERIC Educational Resources Information Center

    West, Alfred W.

    This is the first in a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. Part I of this document deals with physical observations which should be performed during each routine control test. Part II…

  20. THE COUPLED TRICKLING FILTER-ACTIVATED SLUDGE PROCESS: DESIGN AND PERFORMANCE

    EPA Science Inventory

    A case history report was prepared on the upgrading of the Livermore, California, Water Reclamation Plant from a conventional trickling filter plant with tertiary oxidation ponds to a coupled trickling filter-activated sludge plant producing a nitrified effluent low in BOD5, susp...

  1. Bioavailable and biodegradable dissolved organic nitrogen in activated sludge and trickling filter wastewater treatment plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. OXYGEN-ACTIVATED SLUDGE PLANT COMPLETES TWO YEARS OF SUCCESSFUL OPERATION

    EPA Science Inventory

    A detailed report of the conversion to and operational performance of an oxygen-activated sludge system at the Westgate wastewater treatment plant in Fairfax County, Virginia, is given in this report. It is presented in the form of a case history including the time span leading u...

  3. Two-phased hyperthermophilic anaerobic co-digestion of waste activated sludge with kitchen garbage.

    PubMed

    Lee, Myungyeol; Hidaka, Taira; Tsuno, Hiroshi

    2009-11-01

    For co-digestion of waste activated sludge with kitchen garbage, hyperthermophilic digester systems that consisted of an acidogenic reactor operated at hyperthermophilic (70 degrees C) and a methanogenic reactor operated at mesophilic (35 degrees C), thermophilic (55 degrees C) or hyperthermophilic (65 degrees C) conditions in series were studied by comparing with a thermophilic digester system that consisted of thermophilic (55 degrees C) acidogenic and methanogenic reactors. Laboratory scale reactors were operated continuously fed with a substrate blend composed of concentrated waste activated sludge and artificial kitchen garbage. At the acidogenic reactor, solubilization efficiencies of chemical oxygen demand (COD), carbohydrate and protein at 70 degrees C were about 39%, 42% and 54%, respectively, and they were higher than those at 55 degrees C by around 10%. The system of acidogenesis at 70 degrees C and methanogenesis at 55 degrees C was stable and well-functioned in terms of treatment performances and low ammonium nitrogen concentrations. Microbial community analysis was conducted using a molecular biological method. The key microbe determined at the hyperthermophilic acidogenesis step was Coprothermobacter sp., which was possibly concerned with the degradation of protein in waste activated sludge. The present study proved that the hyperthermophilic system was advantageous for treating substrate blends containing high concentrations of waste activated sludge. PMID:19804865

  4. Effects of TiO2 and Ag nanoparticles on polyhydroxybutyrate biosynthesis by activated sludge bacteria.

    PubMed

    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

    2014-12-16

    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. PMID:25409530

  5. TOC, ATP AND RESPIRATION RATE AS CONTROL PARAMETERS FOR THE ACTIVATED SLUDGE PROCESS

    EPA Science Inventory

    This research was conducted to determine the feasibility of using TOC, ATP and respiration rates as tools for controlling a complete mix activated sludge plant handling a significant amount of industrial waste. Control methodology was centered on using F/M ratio which was determi...

  6. FATE OF WATER SOLUBLE AZO DYES IN THE ACTIVATED SLUDGE PROCESS

    EPA Science Inventory

    The objective of this study was to determine the partitioning of water soluble azo dyes in the activated sludge process (ASP). Azo dyes are of concern because some of the dyes, dye precursors , and/or their degradation products such as aromatic amines (which are also dye precurso...

  7. Functionally relevant diversity of closely related Nitrospira in activated sludge

    PubMed Central

    Gruber-Dorninger, Christiane; Pester, Michael; Kitzinger, Katharina; Savio, Domenico F; Loy, Alexander; Rattei, Thomas; Wagner, Michael; Daims, Holger

    2015-01-01

    Nitrospira are chemolithoautotrophic nitrite-oxidizing bacteria that catalyze the second step of nitrification in most oxic habitats and are important for excess nitrogen removal from sewage in wastewater treatment plants (WWTPs). To date, little is known about their diversity and ecological niche partitioning within complex communities. In this study, the fine-scale community structure and function of Nitrospira was analyzed in two full-scale WWTPs as model ecosystems. In Nitrospira-specific 16S rRNA clone libraries retrieved from each plant, closely related phylogenetic clusters (16S rRNA identities between clusters ranged from 95.8% to 99.6%) within Nitrospira lineages I and II were found. Newly designed probes for fluorescence in situ hybridization (FISH) allowed the specific detection of several of these clusters, whose coexistence in the WWTPs was shown for prolonged periods of several years. In situ ecophysiological analyses based on FISH, relative abundance and spatial arrangement quantification, as well as microautoradiography revealed functional differences of these Nitrospira clusters regarding the preferred nitrite concentration, the utilization of formate as substrate and the spatial coaggregation with ammonia-oxidizing bacteria as symbiotic partners. Amplicon pyrosequencing of the nxrB gene, which encodes subunit beta of nitrite oxidoreductase of Nitrospira, revealed in one of the WWTPs as many as 121 species-level nxrB operational taxonomic units with highly uneven relative abundances in the amplicon library. These results show a previously unrecognized high diversity of Nitrospira in engineered systems, which is at least partially linked to niche differentiation and may have important implications for process stability. PMID:25148481

  8. Fate of organic matter during moderate heat treatment of sludge: kinetics of biopolymer and hydrolytic activity release and impact on sludge reduction by anaerobic digestion.

    PubMed

    Lefebvre, D; Dossat-Létisse, V; Lefebvre, X; Girbal-Neuhauser, E

    2014-01-01

    Temperature-phased anaerobic digestion with a 50-70 °C pre-treatment is widely proposed for sludge. Here, such a sludge pre-treatment (65 °C) was studied against the physical, enzymatic and biodegradation processes. The soluble and particulate fractions were analysed in terms of biochemical composition and hydrolytic enzymatic activities. Two kinetics of organic matter solubilisation were observed: a rapid transfer of the weak-linked biopolymers to the water phase, including sugars, proteins or humic acid-like substances, to the water phase, followed by a slow and long-term solubilisation of proteins and humic acid-like substances. In addition, during the heat treatment a significant pool of thermostable hydrolytic enzymes including proteases, lipases and glucosidases remains active. Consequently, a global impact on organic matter was the transfer of the biodegradable chemical oxygen demand (COD) from the particulate to the soluble fraction as evaluated by the biological methane potential test. However, the total biodegradable COD content of the treated sludge remained constant. The heat process improves the bio-accessibility of the biodegradable molecules but doesn't increase the inherent sludge biodegradability, suggesting that the chemistry of the refractory proteins and humic acids seems to be the real limit to sludge digestion. PMID:24804656

  9. High-rate activated sludge communities have a distinctly different structure compared to low-rate sludge communities, and are less sensitive towards environmental and operational variables.

    PubMed

    Meerburg, Francis A; Vlaeminck, Siegfried E; Roume, Hugo; Seuntjens, Dries; Pieper, Dietmar H; Jauregui, Ruy; Vilchez-Vargas, Ramiro; Boon, Nico

    2016-09-01

    High-rate activated sludge processes allow for the recovery of organics and energy from wastewaters. These systems are operated at a short sludge retention time and high sludge-specific loading rates, which results in a higher sludge yield and better digestibility than conventional, low-rate activated sludge. Little is known about the microbial ecology of high-rate systems. In this work, we address the need for a fundamental understanding of how high-rate microbial communities differ from low-rate communities. We investigated the high-rate and low-rate communities in a sewage treatment plant in relation to environmental and operational variables over a period of ten months. We demonstrated that (1) high-rate and low-rate communities are distinctly different in terms of richness, evenness and composition, (2) high-rate community dynamics are more variable and less shaped by deterministic factors compared to low-rate communities, (3) sub-communities of continuously core and transitional members are more shaped by deterministic factors than the continuously rare members, both in high-rate and low-rate communities, and (4) high-rate community members showed a co-occurrence pattern similar to that of low-rate community members, but were less likely to be correlated to environmental and operational variables. These findings provide a basis for further optimization of high-rate systems, in order to facilitate resource recovery from wastewater. PMID:27183209

  10. Interpreting the effect of increasing COD loading rates on the performance of a pre-anoxic MBBR system: implications on the attached and suspended biomass dynamics and nitrification-denitrification activity.

    PubMed

    Lima, P S; Dezotti, M; Bassin, J P

    2016-06-01

    A pre-anoxic MBBR system was subjected to increasing organic loading rates up to 18 gCOD/(m(2) day). At 3 gCOD/(m(2) day), most of the incoming organic matter was removed via denitrification. However, at higher loads, anoxic COD removal became limited by the nitrite/nitrate supply from the aerobic reactor, which assumed an important role in this conversion. Despite the application of low dissolved oxygen (DO) levels (<2 mg/L) in this tank, nitrification was observed to be nearly complete until 8 gCOD/(m(2) day). As the organic input was increased, the maximum specific nitrifying activity gradually declined. Activity tests suggested that an oxygen-limited environment was established in the biofilm. At lower loads [3-8 gCOD/(m(2) day)], the nitrification product obtained was affected by the DO concentration, whereas from 16 to 21 gCOD/(m(2) day), nitrite/nitrate profiles were likely associated with microbial stratification in the biofilm. The results also indicated that the role of the suspended biomass in the overall nitrification and denitrification can be very significant in high loaded MBBRs and should not be neglected, even at low HRTs. PMID:26941244

  11. Response of biodegradation characteristics of unacclimated activated sludge to moderate pressure in a batch reactor.

    PubMed

    Xu, Rui-Xiao; Li, Bing; Zhang, Yong; Si, Ling; Zhang, Xian-Qiu; Xie, Biao

    2016-04-01

    This study was aimed to investigate the effect of moderate pressure on unacclimated activated sludge. Process of organic degradation, variation of carbon dioxide (CO2) concentration of off-gas and characteristics of extracellular polymeric substances (EPS) of activated sludge were analyzed using pressure-atmospheric comparative experiments in bench-scale batch reactors. It was found that moderate pressure increased the degradation rate more dramatically when the biological process ran under a higher organic load with much more oxygen demand, which illuminated that applications of the pressurized method to high concentration organic wastewaters would be more reasonable and practicable. High oxygen transfer impetus increased utilization of oxygen which not only promoted the biodegradation of organics in wastewater, but also led to more EPS consumption in activated sludge. CO2 concentration of off-gas was lower in the earlier stage due to CO2 being pressed into the liquid phase and converted into inorganic carbon (IC). More CO2 emission was observed during the pressurized aerobic process 160 min later. EPS in pressurized reactor was much lower, which may be an important way of sludge reduction by pressurized technology. PMID:26802261

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

    PubMed Central

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

    2015-01-01

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

  13. Entomotoxicity, protease and chitinase activity of Bacillus thuringiensis fermented wastewater sludge with a high solids content.

    PubMed

    Brar, Satinder K; Verma, M; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2009-10-01

    This study investigated the production of biopesticides, protease and chitinase activity by Bacillus thuringiensis grown in raw wastewater sludge at high solids concentration (30 g/L). The rheology of wastewater sludge was modified with addition of Tween-80 (0.2% v/v). This addition resulted in 1.6 and 1.3-fold increase in cell and spore count, respectively. The maximum specific growth rate (micro(max)) augmented from 0.17 to 0.22 h(-1) and entomotoxicity (Tx) increased by 29.7%. Meanwhile, volumetric mass transfer coefficient (k(L)a) showed marked variations during fermentation, and oxygen uptake rate (OUR) increased 2-fold. The proteolytic activity increased while chitinase decreased for Tween amended wastewater sludge, but the entomotoxicity increased. The specific entomotoxicity followed power law when plotted against spore concentration and the relation between Tx and protease activity was linear. The viscosity varied and volume percent of particles increased in Tween-80 amended wastewater sludge and particle size (D(50)) decreased at the end of fermentation. Thus, there was an increase in entomotoxicity at higher suspended solids (30 g/L) as Tween addition improved rheology (viscosity, particle size, surface tension); enhanced maximum growth rate and OUR. PMID:19447031

  14. Stoichiometry and kinetics of poly-{beta}-hydroxybutyrate metabolism in aerobic, slow growing, activated sludge cultures

    SciTech Connect

    Beun, J.J.; Paletta, F.; Loosdrecht, M.C.M. Van; Heijnen, J.J.

    2000-02-20

    This paper discusses the poly-{beta}-hydroxybutyrate (PHB) metabolism in aerobic, slow growing, activated sludge cultures, based on experimental data and on a metabolic model. The dynamic conditions which occur in activated sludge processes were simulated in a 2-L sequencing batch reactor (SBR) by subjecting a mixed microbial population to successive periods of external substrate availability (feast period) and no external substrate availability (famine period). Under these conditions intracellular storage and consumption of PHB was observed. It appeared that in the feast period, 66% to almost 100% of the substrate consumed is used for storage of PHB, the remainder is used for growth and maintenance processes. Furthermore, it appeared that at high sludge retention time (SRT) the growth rate in the feast and famine periods was the same. With decreasing SRT the growth rate in the feast period increased relative to the growth rate in the famine period. Acetate consumption and PHB production in the feast period both proceeded with a zero-order rate in acetate and PHB concentration respectively. PHB consumption in the famine period could best be described kinetically with a nth order degradation equation in PHB concentration. The obtained results are discussed in the context of the general activated sludge models.

  15. The impact of peroxydisulphate and peroxymonosulphate on disintegration and settleability of activated sludge.

    PubMed

    Wacławek, Stanisław; Grübel, Klaudiusz; Černík, Miroslav

    2016-01-01

    Chemical treatment processes have mostly been considered as an efficient way for biosolid minimization. The improvement of sludge dewatering was more a welcome side-effect of these sequential processes. In this study, heat-activated sodium peroxydisulphate (PDS) and potassium peroxymonosulphate (MPS) were applied in order to disintegrate waste activated sludge (WAS). PDS and MPS treatment of WAS results in the polymer transfer of organic matter from the solid phase to the liquid phase. Our research work was done for chemical disintegration of WAS by PDS and MPS in doses of 0.2%, 0.4%, 0.6%, 0.8% and 1% (169.5, 339.0, 508.5, 678.0 and 847.5 mg [Formula: see text]) activated at temperatures of 60°C and 90°C for 30 min. The application of these methods causes the soluble chemical oxygen demand value to increase in the supernatant. In addition, there was a positive influence on the sludge volume index which decreased for the highest doses of PDS of over 63% and 77% and MPS of over 78% and 82% through heat activation at temperatures of 60°C and 90°C, respectively. Furthermore, MPS was more successful in the floc particle destruction, therefore it caused a higher sludge settlement acceleration (sedimentation/compaction speed) than PDS. The experimental results demonstrated that the application of heat-activated PDS and MPS may become a novel effective way of processing sewage sludge. PMID:26503018

  16. Ammonium Uptake by Phytoplankton Regulates Nitrification in the Sunlit Ocean

    PubMed Central

    Smith, Jason M.; Chavez, Francisco P.; Francis, Christopher A.

    2014-01-01

    Nitrification, the microbial oxidation of ammonium to nitrate, is a central part of the nitrogen cycle. In the ocean’s surface layer, the process alters the distribution of inorganic nitrogen species available to phytoplankton and produces nitrous oxide. A widely held idea among oceanographers is that nitrification is inhibited by light in the ocean. However, recent evidence that the primary organisms involved in nitrification, the ammonia-oxidizing archaea (AOA), are present and active throughout the surface ocean has challenged this idea. Here we show, through field experiments coupling molecular genetic and biogeochemical approaches, that competition for ammonium with phytoplankton is the strongest regulator of nitrification in the photic zone. During multiday experiments at high irradiance a single ecotype of AOA remained active in the presence of rapidly growing phytoplankton. Over the course of this three day experiment, variability in the intensity of competition with phytoplankton caused nitrification rates to decline from those typical of the lower photic zone (60 nmol L−1 d−1) to those in well-lit layers (<1 nmol L−1 d−1). During another set of experiments, nitrification rates exhibited a diel periodicity throughout much of the photic zone, with the highest rates occurring at night when competition with phytoplankton is lowest. Together, the results of our experiments indicate that nitrification rates in the photic zone are more strongly regulated by competition with phytoplankton for ammonium than they are by light itself. This finding advances our ability to model the impact of nitrification on estimates of new primary production, and emphasizes the need to more strongly consider the effects of organismal interactions on nutrient standing stocks and biogeochemical cycling in the surface of the ocean. PMID:25251022

  17. Ammonium uptake by phytoplankton regulates nitrification in the sunlit ocean.

    PubMed

    Smith, Jason M; Chavez, Francisco P; Francis, Christopher A

    2014-01-01

    Nitrification, the microbial oxidation of ammonium to nitrate, is a central part of the nitrogen cycle. In the ocean's surface layer, the process alters the distribution of inorganic nitrogen species available to phytoplankton and produces nitrous oxide. A widely held idea among oceanographers is that nitrification is inhibited by light in the ocean. However, recent evidence that the primary organisms involved in nitrification, the ammonia-oxidizing archaea (AOA), are present and active throughout the surface ocean has challenged this idea. Here we show, through field experiments coupling molecular genetic and biogeochemical approaches, that competition for ammonium with phytoplankton is the strongest regulator of nitrification in the photic zone. During multiday experiments at high irradiance a single ecotype of AOA remained active in the presence of rapidly growing phytoplankton. Over the course of this three day experiment, variability in the intensity of competition with phytoplankton caused nitrification rates to decline from those typical of the lower photic zone (60 nmol L-1 d-1) to those in well-lit layers (<1 nmol L-1 d-1). During another set of experiments, nitrification rates exhibited a diel periodicity throughout much of the photic zone, with the highest rates occurring at night when competition with phytoplankton is lowest. Together, the results of our experiments indicate that nitrification rates in the photic zone are more strongly regulated by competition with phytoplankton for ammonium than they are by light itself. This finding advances our ability to model the impact of nitrification on estimates of new primary production, and emphasizes the need to more strongly consider the effects of organismal interactions on nutrient standing stocks and biogeochemical cycling in the surface of the ocean. PMID:25251022

  18. Effects of long term irrigation with polluted water and sludge amendment on some soil enzyme activities

    SciTech Connect

    Topac, F.O.; Baskaya, H.S.; Alkan, U.; Katkat, A.V.

    2008-01-15

    The objective of this study was to determine the effects of wastewater sludge-fly ash mixtures on urease, dehydrogenase, alkaline phosphatase and beta-glucosidase activities in soils. In order to evaluate the probable effects of previous soil management practices (irrigation with polluted water) on soil enzymes, two different soil samples which were similar in physical properties, but different in irrigation practice were used. The application of wastewater sludges supplemented with varying doses of fly ash increased potential enzyme activities for a short period of time (3 months) in comparison to unamended soils. However, the activity levels generally showed a decreasing trend with increasing ash ratios indicating the inhibitory effect of fly ash. The urease and dehydrogenase activities were particularly lower in soils irrigated from a polluted stream, indicating the negative effects of the previous soil management on soil microbial activity.

  19. Optimization of Ozonation Process for the Reduction of Excess Sludge Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design

    PubMed Central

    Subha, B.; Muthukumar, M.

    2012-01-01

    Sago industries effluent containing large amounts of organic content produced excess sludge which is a serious problem in wastewater treatment. In this study ozonation has been employed for the reduction of excess sludge production in activated sludge process. Central composite design is used to study the effect of ozone treatment for the reduction of excess sludge production in sago effluent and to optimise the variables such as pH, ozonation time, and retention time. ANOVA showed that the coefficient determination value (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. PMID:22593666

  20. Assessment of free nitrous acid pre-treatment on a mixture of primary sludge and waste activated sludge: Effect of exposure time and concentration.

    PubMed

    Zahedi, S; Icaran, P; Yuan, Z; Pijuan, M

    2016-09-01

    Free nitrous acid (FNA) has been shown to enhance the biodegradability of waste activated sludge (WAS) but its effectiveness on the pre-treatment of mixed sludge is not known. This study explores the effectiveness of four different FNA concentrations (0, 2.49, 3.55, 4.62mgN-HNO2/L) and three exposure times (2, 5, 9h) lower than the ones reported in literature (24h) on WAS characteristics and specific methane production (SMP). FNA pre-treatment reduced sludge cell viability below 10% in all cases after an exposure time of 5h, increasing the solubility of the organic matter. The treated mixed sludge was used as substrate for the biochemical methane production tests to assess its SMP. Results showed a significant increase (up to 25%) on SMP when the sludge was pretreated with the lowest FNA concentration (2.49mgN-HNO2/L) during 2 and 5h but did not show any improvement at longer exposure times or higher FNA concentrations. PMID:27318660

  1. pH-dependent biotransformation of ionizable organic micropollutants in activated sludge.

    PubMed

    Gulde, Rebekka; Helbling, Damian E; Scheidegger, Andreas; Fenner, Kathrin

    2014-12-01

    Removal of micropollutants (MPs) during activated sludge treatment can mainly be attributed to biotransformation and sorption to sludge flocs, whereby the latter process is known to be of minor importance for polar organic micropollutants. In this work, we investigated the influence of pH on the biotransformation of MPs with cationic-neutral speciation in an activated sludge microbial community. We performed batch biotransformation, sorption control, and abiotic control experiments for 15 MPs with cationic-neutral speciation, one control MP with neutral-anionic speciation, and two neutral MPs at pHs 6, 7, and 8. Biotransformation rate constants corrected for sorption and abiotic processes were estimated from measured concentration time series with Bayesian inference. We found that biotransformation is pH-dependent and correlates qualitatively with the neutral fraction of the ionizable MPs. However, a simple speciation model based on the assumption that only the neutral species is efficiently taken up and biotransformed by the cells tends to overpredict the effect of speciation. Therefore, additional mechanisms such as uptake of the ionic species and other more complex attenutation mechanisms are discussed. Finally, we observed that the sorption coefficients derived from our control experiments were small and showed no notable pH-dependence. From this we conclude that pH-dependent removal of polar, ionizable organic MPs in activated sludge systems is less likely an effect of pH-dependent sorption but rather of pH-dependent biotransformation. The latter has the potential to cause marked differences in the removal of polar, ionizable MPs at different operational pHs during activated sludge treatment. PMID:25337862

  2. Environmental and resource implications of phosphorus recovery from waste activated sludge.

    PubMed

    Sørensen, Birgitte Lilholt; Dall, Ole Leinikka; Habib, Komal

    2015-11-01

    Phosphorus is an essential mineral resource for the growth of crops and thus necessary to feed the ever increasing global population. The essentiality and irreplaceability of phosphorus in food production has raised the concerns regarding the long-term phosphorus availability and the resulting food supply issues in the future. Hence, the recovery of phosphorus from waste activated sludge and other waste streams is getting huge attention as a viable solution to tackle the potential availability issues of phosphorus in the future. This study explores the environmental implications of phosphorus recovery from waste activated sludge in Denmark and further elaborates on the potential availability or scarcity issue of phosphorus today and 2050. Life cycle assessment is used to assess the possibility of phosphorus recovery with little or no environmental impacts compared to the conventional mining. The phosphorus recovery method assessed in this study consists of drying process, and thermal gasification of the waste activated sludge followed by extraction of phosphorus from the ashes. Our results indicate that the environmental impacts of phosphorus recovery in an energy efficient process are comparable to the environmental effects from the re-use of waste activated sludge applied directly on farmland. Moreover, our findings conclude that the general recommendation according to the waste hierarchy, where re-use of the waste sludge on farmland is preferable to material and energy recovery, is wrong in this case. Especially when phosphorus is a critical resource due to its life threatening necessity, lack of substitution options and potential future supply risk originating due to the high level of global supply concentration. PMID:25792438

  3. Treatment of nitrogen-rich wastewater using partial nitrification and anammox in the CANON process.

    PubMed

    Third, K A; Paxman, J; Schmid, M; Strous, M; Jetten, M S M; Cord-Ruwisch, R

    2005-01-01

    Partial nitrification combined with Anammox in a single reactor (the CANON process) is an energy-efficient N-removal technology that could substantially lower the N-load of a WWTP by separate treatment of nitrogen-rich side streams, preventing the need for extensive expansion and reducing the total energy requirement. This study looks at the enrichment of Anammox from activated sludge and its application in the CANON process on lab-scale. The aim was to identify the critical process control parameters necessary for successful operation of CANON. An Anammox culture capable of removing 0.6 kg N/m3/d was enriched in 14 weeks in a sequencing batch reactor. Nitrifying biomass was inoculated into the Anammox reactor (10% v/v) together with limited oxygen supply (< 8 mL/min) to initiate the CANON process in continuous culture. The small flocs formed by the biomass (< 1000 microm) were sensitive to low O2 concentrations (< 0.1 mg/L) which prevented simultaneous nitrification and Anammox. Operation with 20 min aerobiosis and 30 min anaerobiosis was necessary to achieve sustained, completely autotrophic N-removal for an extended period at a rate of 0.08 kg N/m3/d. Essential process control parameters for stable CANON operation were the nitrite concentration, oxygen concentration, pH and the temperature. PMID:16235745

  4. A hybrid anaerobic membrane bioreactor coupled with online ultrasonic equipment for digestion of waste activated sludge.

    PubMed

    Xu, Meilan; Wen, Xianghua; Yu, Zhiyong; Li, Yushan; Huang, Xia

    2011-05-01

    Anaerobic membrane bioreactor and online ultrasonic equipment used to enhance membrane filtration were coupled to form a hybrid system (US-AnMBR) designed for long-term digestion of waste activated sludge. The US-AnMBR was operated under volatile solids loading rates of 1.1-3.7 gVS/L·d. After comprehensive studies on digestion performance and membrane fouling control in the US-AnMBR, the final loading rate was determined to be 2.7 gVS/L·d with 51.3% volatile solids destruction. In the US-AnMBR, the improved digestion was due to enhanced sludge disintegration, as indicated by soluble matter comparison in the supernatant and particle size distribution in the digested sludge. Maximum specific methanogenic activity revealed that ultrasound application had no negative effect on anaerobic microorganisms. Furthermore, implementing ultrasound effectively controlled membrane fouling and successfully facilitated membrane bioreactor operation. This lab-scale study demonstrates the potential feasibility and effectiveness of setting up a US-AnMBR system for sludge digestion. PMID:21421308

  5. Effects of heavy metal and other elemental additives to activated sludge on growth of Eisenia foetida

    SciTech Connect

    Hartenstein, R.; Neuhauser, E.F.; Narahara, A.

    1981-09-01

    The approximate level at which added concentrations of certain elements would cause an activated sludge to induce a toxic effect upon the growth of Eisenia foetida was determined. During 43 trials on sludge samples obtained throughout 1 year of study, earthworms grew from 3 to 10 mg live wt at hatching to 792 mg +- 18% (mean +- C.V.) in 8 weeks, when sludge was 24/sup 0/C and contained no additives. None of several elements commonly used in microbial growth media enhanced the growth rate of the earthworm. At salt concentrations up to about 6.6% on a dry wt basis, none of six anions tested was in and of itself toxic, while five of 15 cations - Co, Hg, Cu, Ni, and Cd - appeared specifically to inhibit growth rate or cause death. Manganese, Cr, and Pb were innocuous even at the highest levels of application - 22,000, 46,000, and 52,000 mg/kg, respectively. Neither the anionic nor cationic component of certain salts, such as NaCl or NH/sub 4/Cl, could be said to inhibit growth, which occurred only at high concentrations of these salts (about 3.3 and/or 6.6%). Below 7 mmho/cm, toxicity could not be correlated with electrolytic conductance, though higher values may help to explain the nonspecific growth inhibitory effects of salts like NaCl and KCl. Nor could toxicity ever be ascribed to hydrogen ion activity, since sludge pH was not altered even at the highest salt dose. It is concluded that except under very extreme conditions, the levels of heavy metals and salts generally found in activated sludges will not have an adverse affect on the growth of E. foetida.

  6. Characterization of activated sludge exocellular polymers using several cation-associated extraction methods.

    PubMed

    Park, Chul; Novak, John T

    2007-04-01

    Evaluation of prior research and preliminary investigations in our laboratory led to the development of an extraction strategy that can be used to target different cations in activated sludge floc and extract their associated extracellular polymeric substances (EPS). The methods we used were the cation exchange resin (CER) procedure, base extraction, and sulfide addition to extract EPS linked with divalent cations, Al, and Fe, respectively. A comparison of sludge cations before and after CER extraction revealed that most of Ca(2+) and Mg(2+) were removed while Fe and Al remained intact, suggesting that this method is highly selective for Ca(2+) and Mg(2+)-bound EPS. The correlation between sludge Fe and sulfide-extracted EPS was indicative of selectivity of this method for Fe-bound EPS. The base extraction was less specific than the other methods but it was the method releasing the largest amount of Al into the extract, indicating that the method extracted Al-bound EPS. Concomitantly, the composition of extracted EPS and the amino acid composition differed for the three methods, indicating that EPS associated with different metals were not the same. The change in EPS following anaerobic and aerobic digestion was also characterized by the three extraction methods. CER-extracted EPS were reduced after aerobic digestion while they changed little by anaerobic digestion. On the other hand, anaerobic digestion was associated with the decrease in sulfide-extracted EPS. These results suggest that different types of cation-EPS binding mechanisms exist in activated sludge and that each cation-associated EPS fraction imparts unique digestion characteristics to activated sludge. PMID:17346764

  7. Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants?

    PubMed

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

    2016-01-01

    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. PMID:26540311

  8. No nitrification in lakes below pH 3.

    PubMed

    Jeschke, Christina; Falagán, Carmen; Knöller, Kay; Schultze, Martin; Koschorreck, Matthias

    2013-12-17

    Lakes affected by acid mine drainage (AMD) or acid rain often contain elevated concentrations of ammonium, which threatens water quality. It is commonly assumed that this is due to the inhibition of microbial nitrification in acidic water, but nitrification was never directly measured in mine pit lakes. For the first time, we measured nitrification by (15)NH4Cl isotope tracer addition in acidic as well as neutral mine pit lakes in Spain and Germany. Nitrification activity was only detected in neutral lakes. In acidic lakes no conversion of (15)NH4(+) to (15)NO3(-) was observed. This was true both for the water column as well as for biofilms on the surface of macrophytes or dead wood and the oxic surface layer of the sediment. Stable isotope analysis of nitrate showed (18)O values typical for nitrification only in neutral lakes. In a comparison of NH4(+) concentrations in 297 surface waters with different pH, ammonium concentrations higher 10 mg NH4-N L(-1) were only observed in lakes below pH 3. On the basis of the results from stable isotope investigations and the examination of a metadata set we conclude that the lower limit for nitrification in lakes is around pH 3. PMID:24229046

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

    PubMed

    Guo, Junyuan; Yang, Chunping; Zeng, Guangming

    2013-09-01

    Sterilization, alkaline-thermal and acid-thermal treatments were applied to activated sludge and the pre-treated sludge was used as raw material for Rhodococcus R3 to produce polymeric substances. After 60 h of fermentation, bioflocculant of 2.7 and 4.2 g L(-1) were produced in sterilized and alkaline-thermal treated sludge as compared to that of 0.9 g L(-1) in acid-thermal treated sludge. Response surface methodology (RSM) was employed to optimize the treatment process of swine wastewater using the composite of bioflocculant and zeolite modified by calcining with MgO. The optimal flocculating conditions were bioflocculant of 24 mg L(-1), modified zeolite of 12 g L(-1), CaCl2 of 16 mg L(-1), pH of 8.3 and contact time of 55 min, and the corresponding removal rates of COD, ammonium and turbidity were 87.9%, 86.9%, and 94.8%. The use of the composite by RSM provides a feasible way to improve the pollutant removal efficiencies and recycle high-level of ammonium from wastewater. PMID:23810950

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

    PubMed

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

    2015-09-01

    The disintegration of raw sludge is very important for enhancement of the biogas production in anaerobic digestion process as it provides easily degradable substrate for microorganisms to perform maximum sludge treatment efficiency and stable digestion of sludge at lower costs. In the present study the disintegration was studied by using a novel rotation generator of hydrodynamic cavitation (RGHC). At the first stage the analysis of hydrodynamics of the RGHC were made with tap water, where the cavitation extent and aggressiveness was evaluated. At the second stage RGHC was used as a tool for pretreatment of a waste-activated sludge (WAS), collected from wastewater treatment plant (WWTP). In case of WAS the disintegration rate was measured, where the soluble chemical oxygen demand (SCOD) and soluble Kjeldahl nitrogen were monitored and microbiological pictures were taken. The SCOD increased from initial 45 mg/L up to 602 mg/L and 12.7% more biogas has been produced by 20 passes through RGHC. The results were obtained on a pilot bioreactor plant, volume of 400 L. PMID:25596776

  11. [Effect of powdered activated carbon on the sludge mixed liquor characteristics and membrane fouling of MBR].

    PubMed

    Li, Shao-Feng; Gao, Yuan

    2011-02-01

    Effect of dosing powder activated carbon (PAC) on the characteristics of the sludge mixed liquor in membrane bioreactor (MBR) was investigated by parallel tests. And the reason that PAC mitigated membrane fouling was also explored. The results showed that PAC could decrease mixture viscosity and increase sludge particle size, which led to less trans-membrane pressure developing. Extracellular polymer substances (EPS) content, sludge specific resistance and cake layer resistance (R(c)) had a good correlation. Adding PAC could decrease EPS concentration, sludge specific resistance and then slow down the increase of R(c), which mitigated membrane fouling. Membrane pore blocking resistance (R(p)) increased exponentially with increasing of the soluble microbial products (SMP) concentration in the supernatant. Dosing PAC reduced the SMP concentration and slowed down the growth rate of R(p), which was helpful to mitigating membrane fouling. R(c) and R(p) increased along with the operation of MBRs and R(c)/R(f) (26.32% -63.16%) was always greater than R(p)/R(f) (7.89% -35.32%) which suggested the R(c) was the main factor in membrane fouling. Moreover, it was also found that controlling of dosing PAC on R(c) was better than it on R(p). PMID:21528575

  12. Storage and degradation of poly-beta-hydroxybutyrate in activated sludge under aerobic conditions.

    PubMed

    Dircks, K; Henze, M; van Loosdrecht, M C; Mosbaek, H; Aspegren, H

    2001-06-01

    This research analyses the accumulation and degradation of poly-beta-hydroxybutyrate (PHB) in experiments with pulse addition of acetate to samples of activated sludge from pilot-plant and full-scale wastewater treatment plants. The experiments are divided into two periods: a feast period defined as the time when acetate is consumed and a famine period when the added acetate has been exhausted. In the feast period the significant process occurring is the production of PHB from acetate. The produced PHB is utilised in the famine period for production of glycogen and biomass. According to modelling results approximately 90% of the total potential growth occurs in the famine period utilising the stored PHB. The degradation rate for PHB in the famine period is found to be dependent on the level of PHB obtained at the end of the feast period. It was found that multiple order kinetics gives a good description of the rate of PHB degradation. The examined sludge of low SRT origin is found to degrade PHB faster than long SRT sludge at high fractions of PHB. The observed yield of glycogen on PHB in the famine period is in the range of 0.22-0.33 g COD/g COD depending on the SRT. The storage pool of glycogen in the examined sludge is more slowly degraded than PHB (COD/COD/h). PMID:11358308

  13. Addition of Al and Fe salts during treatment of paper mill effluents to improve activated sludge settlement characteristics.

    PubMed

    Agridiotis, V; Forster, C F; Carliell-Marquet, C

    2007-11-01

    Metal salts, ferrous sulphate and aluminium chloride, were added to laboratory-scale activated sludge plant treating paper mill effluents to investigate the effect on settlement characteristics. Before treatment the sludge was filamentous, had stirred sludge volume index (SSVI) values in excess of 300 and was moderately hydrophobic. The use of FeSO4.7H2O took three weeks to reduce the SSVI to 90. Microscopic examination showed that Fe had converted the filamentous flocs into a compact structure. When the iron dosing was stopped, the sludge returned to its bulking state within four weeks. In a subsequent trial, the addition of AlCl3 initially resulted in an improvement of the settlement index but then caused deterioration of the sludge properties. It is possible that aluminium was overdosed and caused charge reversal, increasing the SSVI. PMID:17113285

  14. The effect of iron dosing on reducing waste activated sludge in the oxic-settling-anoxic process.

    PubMed

    Yagci, Nevin; Novak, John T; Randall, Clifford W; Orhon, Derin

    2015-10-01

    This study evaluates the biological solid reduction in a conventional activated sludge system with an anoxic/anaerobic side stream reactor receiving 1/10 of return sludge mass. Influent iron concentrations and feeding modes were changed to explore the consistency between the influent iron concentration and yield values and to assess the impact of feeding pattern. The results indicated that sludge reduction occurs during alternately exposure of sludge to aerobic and anoxic/anaerobic conditions in a range of 38-87%. The sludge reduction values reached a maximum level with the higher iron concentrations. Thus, it is concluded that this configuration is more applicable for plants receiving high iron concentrations in the wastewaters. PMID:26141280

  15. Distribution variation of a metabolic uncoupler, 2,6-dichlorophenol (2,6-DCP) in long-term sludge culture and their effects on sludge reduction and biological inhibition.

    PubMed

    Tian, Yu; Zhang, Jun; Wu, Di; Li, Zhipeng; Cui, Yanni

    2013-01-01

    Distribution variation of a metabolic uncoupler, 2,6-dichlorophenol (2,6-DCP), in long-term sludge culture was studied, and the effects on sludge reduction and biological inhibition of this chemical during the 90-day operation were established. The extracellular polymeric substance (EPS) matrix functioned as a protective barrier for the bacteria inside sludge flocs to 2,6-DCP, resulting in the transfer of 2,6-DCP from the liquid phase to the activated sludge fraction. Significant sludge reduction (about 40%) was observed after the addition of 2,6-DCP in the first 40 days, while the ineffective function of 2,6-DCP in sludge reduction (days 70-90) might be correlated to the EPS protection mechanism. The inhibitory effect of 2,6-DCP on the COD removal was extremely lower than on the nitrification performance due to the fact that 2,6-DCP was much more toxic to autotrophic microorganisms than heterotrophic microorganisms. Moreover, both of them recovered to a higher level again with the transfer potential of 2,6-DCP to sludge. Thus, the application of metabolic uncoupler for excess sludge reduction should be cautious. PMID:23123050

  16. Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation.

    PubMed

    Chen, Zhan; Zhang, Weijun; Wang, Dongsheng; Ma, Teng; Bai, Runying; Yu, Dezhong

    2016-10-15

    The effects of combined calcium peroxide (CaO2) oxidation with chemical re-flocculation on dewatering performance and physicochemical properties of waste activated sludge was investigated in this study. The evolutions of extracellular polymeric substances (EPS) distribution, composition and morphological properties were analyzed to unravel the sludge conditioning mechanism. It was found that sludge filtration performance was enhanced by calcium peroxide oxidation with the optimal dosage of 20 mg/gTSS. However, this enhancement was not observed at lower dosages due to the absence of oxidation and the performance deteriorated at higher dosages because of the release of excess EPS, mainly as protein-like substances. The variation in soluble EPS (SEPS) component can be fitted well with pseudo-zero-order kinetic model under CaO2 treatment. At the same time, extractable EPS content (SEPS and loosely bound EPS (LB-EPS)) were dramatically increased, indicating sludge flocs were effectively broken and their structure became looser after CaO2 addition. The sludge floc structure was reconstructed and sludge dewaterability was significantly enhanced using chemical re-flocculation (polyaluminium chloride (PACl), ferric iron (FeCl3) and polyacrylamide (PAM)). The inorganic coagulants performed better in improving sludge filtration dewatering performance and reducing cake moisture content than organic polymer, since they could act as skeleton builders and decrease the sludge compressibility. PMID:27450355

  17. Occurrence and activity of sulphate reducing bacteria in aerobic activated sludge systems.

    PubMed

    van den Brand, T P H; Roest, K; Chen, G H; Brdjanovic, D; van Loosdrecht, M C M

    2015-03-01

    In the sewage or wastewater treatment plant, biological sulphate reduction can occur spontaneously or be applied beneficially for its treatment. The results of this study can be applied to control SRB in the sewage and WWTP. Therefore, population diversity analyses of SRB for nine activated sludge wastewater treatment plants (WWTP) in the Netherlands and the effect of long-term (months) oxygen exposures on the SRB activity were carried out. T-RFLP and clone sequencing analyses of winter and summer samples revealed that (1) all WWTP have a similar SRB population, (2) there is no seasonal impact (10-20 °C) on the SRB population present in the WWTP and (3) Desulfobacter postgatei, Desulfovibrio desulfuricans and Desulfovibrio intestinalis were the most common and dominant SRB species observed in these samples, and origin from the sewage. Short term activity tests demonstrated that SRB were not active in the aerobic WWTP, but while flushed with N2-gas SRB became slightly active after 3 h. In a laboratory reactor at a dissolved oxygen concentration of <2 %, sulphate reduction occurred and 89 % COD removal was achieved. SRB grew in granules, in order to protect themselves for oxygen exposures. SRB are naturally present in aerobic WWTP, which is due to the formation of granules. PMID:25649202

  18. Effect of textile auxiliaries on the biodegradation of dyehouse effluent in activated sludge.

    PubMed

    Arslan Alaton, Idil; Insel, Güçlü; Eremektar, Gülen; Germirli Babuna, Fatos; Orhon, Derin

    2006-03-01

    The textile industry is confronted with serious environmental problems associated with its immense wastewater discharge, substantial pollution load, extremely high salinity, and alkaline, heavily coloured effluent. Particular sources of recalcitrance and toxicity in dyehouse effluent are two frequently used textile auxiliaries; i.e. dye carriers and biocidal finishing agents. The present experimental work reports the observation of scientific and practical significance related with the effect of two commercially important textile dye carriers and two biocidal finishing agents on biological activated sludge treatment at a textile preparation, dyeing and finishing plant in Istanbul. Respirometric measurements of the dyehouse effluent spiked with the selected textile chemicals were carried out for the assessment of the "readily biodegradable COD fraction" of the wastewater. The respirometric data obtained to visualize the effect of the selected textile auxiliaries on biomass activity was evaluated by an adopted activated sludge model. Results have indicated that the tested biocides did not exert any significant inhibitory effect on the treatment performance of the activated sludge reactor at the concentrations usually encountered in the final, total dyehouse effluent. The situation with the dye carriers was inherently different; one dye carrier appeared to be highly toxic and caused serious inhibition of the microbial respirometric activity, whereas the other dye carrier, also known as the more ecological alternative, i.e. the "Eco-Carrier", appeared to be biodegradable. Finally, the respirometric profile obtained for the Eco-Carrier was described by a simplified respirometric model. PMID:16098558

  19. Ozonation effects for excess sludge reduction on bacterial communities composition in a full-scale activated sludge plant for domestic wastewater treatment.

    PubMed

    Chiellini, C; Gori, R; Tiezzi, A; Brusetti, L; Pucciarelli, S; D'Amato, E; Chiavola, A; Sirini, P; Lubello, C; Petroni, G

    2014-01-01

    Activated sludge process is the most widely diffused system to treat wastewater to control the discharge of pollutants into the environment. Microorganisms are responsible for the removal of organic matter, nitrogen, phosphorous and other emerging contaminants. The environmental conditions of biological reactors significantly affects the ecology of the microbial community and, therefore, the performance of the treatment process. In the last years, ozone has been used to reduce excess sludge production by wastewater treatment plants (WWTPs), whose disposal represents one of the most relevant operational costs. The ozonation process has demonstrated to be a viable method to allow a consistent reduction in excess sludge. This study was carried out in a full-scale plant treating municipal wastewater in two parallel lines, one ozonated in the digestion tank and another used as a control. Bacterial communities of samples collected from both lines of digestion thanks were then compared to assess differences related to the ozonation treatment. Data were then analysed with terminal restriction fragment length polymorphism (T-RFLP) analysis on 16S rRNA gene. Differences between bacterial communities of both treated and untreated line appeared 2 weeks after the beginning of the treatment. Results demonstrated that ozonation treatment significantly affected the activated sludge in WWTP. PMID:24701944

  20. Molecular detection, isolation, and physiological characterization of functionally dominant phenol-degrading bacteria in activated sludge.

    PubMed

    Watanabe, K; Teramoto, M; Futamata, H; Harayama, S

    1998-11-01

    DNA was isolated from phenol-digesting activated sludge, and partial fragments of the 16S ribosomal DNA (rDNA) and the gene encoding the largest subunit of multicomponent phenol hydroxylase (LmPH) were amplified by PCR. An analysis of the amplified fragments by temperature gradient gel electrophoresis (TGGE) demonstrated that two major 16S rDNA bands (bands R2 and R3) and two major LmPH gene bands (bands P2 and P3) appeared after the activated sludge became acclimated to phenol. The nucleotide sequences of these major bands were determined. In parallel, bacteria were isolated from the activated sludge by direct plating or by plating after enrichment either in batch cultures or in a chemostat culture. The bacteria isolated were classified into 27 distinct groups by a repetitive extragenic palindromic sequence PCR analysis. The partial nucleotide sequences of 16S rDNAs and LmPH genes of members of these 27 groups were then determined. A comparison of these nucleotide sequences with the sequences of the major TGGE bands indicated that the major bacterial populations, R2 and R3, possessed major LmPH genes P2 and P3, respectively. The dominant populations could be isolated either by direct plating or by chemostat culture enrichment but not by batch culture enrichment. One of the dominant strains (R3) which contained a novel type of LmPH (P3), was closely related to Valivorax paradoxus, and the result of a kinetic analysis of its phenol-oxygenating activity suggested that this strain was the principal phenol digester in the activated sludge. PMID:9797297

  1. Fate and effect of naphthenic acids on oil refinery activated sludge wastewater treatment systems.

    PubMed

    Misiti, Teresa; Tezel, Ulas; Pavlostathis, Spyros G

    2013-01-01

    Naphthenic acids (NAs) are a complex group of alkyl-substituted acyclic, monocyclic and polycyclic carboxylic acids present in oil sands process waters, crude oil, refinery wastewater and petroleum products. Crude oil, desalter brine, influent, activated sludge mixed liquor and effluent refinery samples were received from six United States refineries. The total acid number (TAN) of the six crudes tested ranged from 0.12 to 1.5 mg KOH/g crude oil and correlated to the total NA concentration in the crudes. The total NA concentration in the desalter brine, influent, activated sludge mixed liquor and effluent samples ranged from 4.2 to 40.4, 4.5 to 16.6, 9.6 to 140.3 and 2.8 to 11.6 mg NA/L, respectively. The NAs in all wastewater streams accounted for less than 16% of the total COD, indicating that many other organic compounds are present and that NAs are a minor component in refinery wastewaters. Susceptibility tests showed that none of the activated sludge heterotrophic microcosms was completely inhibited by NAs up to 400 mg/L. Growth inhibition ranging from 10 to 59% was observed in all microcosms at and above 100 mg NA/L. NAs chronically-sorbed to activated sludge mixed liquor biomass and powdered activated carbon (PAC) were recalcitrant and persistent. More than 80% of the total NAs remained in the solid phase at the end of the 10-day desorption period (five successive desorption steps). Throughout a 90-day incubation period, the total NA concentration decreased by 33 and 51% in PAC-free and PAC-containing mixed liquor microcosms, respectively. The lower molecular weight fraction of NAs was preferentially degraded in both mixed liquors. The persistence of the residual, higher molecular weight NAs is likely a combination of molecular recalcitrance and decreased bioavailability when chronically-sorbed to the biomass and/or PAC. PMID:23141768

  2. Evidence for biological nitrification inhibition in Brachiaria pastures

    PubMed Central

    Subbarao, G. V.; Nakahara, K.; Hurtado, M. P.; Ono, H.; Moreta, D. E.; Salcedo, A. F.; Yoshihashi, A. T.; Ishikawa, T.; Ishitani, M.; Ohnishi-Kameyama, M.; Yoshida, M.; Rondon, M.; Rao, I. M.; Lascano, C. E.; Berry, W. L.; Ito, O.

    2009-01-01

    Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named “brachialactone,” this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a γ-lactone ring. It contributed 60–90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in Nitrosomonas. Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NH4+) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NH4+. Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment. PMID:19805171

  3. Model development with defined biological mechanisms for xenobiotic treatment activated sludge at steady state.

    PubMed

    Chong, Nyuk-Min

    2015-06-01

    Activated sludge treatment of a xenobiotic organic compound, much different from treatment of biogenic organics, must be modeled with interactions involving a two-part biomass of degrader and nondegrader, which selectively or competitively grow on a two-part substrate of input xenobiotic and its biogenic metabolites. A xenobiotic treatment model was developed which incorporates kinetics of the growth of degrader and nondegrader, the line dividing metabolites into xenobiotic and biogenic, yields of degrader and nondegrader from utilization of their parts of substrates, and kinetics of degrader reversion to nondegrader due to instability of the degradative element degraders carry. Experimental activated sludge operated for treatment of a xenobiotic generated data for calibration of the model. With the input of influent xenobiotic concentration, mean cell and hydraulic residence times, and calibrated parameters, the model readily outputs concentrations of degrader, nondegrader, and effluent biogenic residue that closely match the results obtained from experiments. PMID:25561268

  4. Degradation of norgestrel by bacteria from activated sludge: comparison to progesterone.

    PubMed

    Liu, Shan; Ying, Guang-Guo; Liu, You-Sheng; Peng, Fu-Qiang; He, Liang-Ying

    2013-09-17

    Natural and synthetic progestagens in the environment have become a concern due to their adverse effects on aquatic organisms. Laboratory studies were performed to investigate aerobic biodegradation of norgestrel by bacteria from activated sludge in comparison with progesterone, and to identify their degradation products and biotransformation pathways. The degradation of norgestrel followed first order reaction kinetics (T1/2 = 12.5 d), while progesterone followed zero order reaction kinetics (T1/2 = 4.3 h). Four and eight degradation products were identified for norgestrel and progesterone, respectively. Six norgestrel-degrading bacterial strains (Enterobacter ludwigii, Aeromonas hydrophila subsp. dhakensis, Pseudomonas monteilii, Comamonas testosteroni, Exiguobacterium acetylicum, and Chryseobacterium indologenes) and one progesterone-degrading bacterial strain (Comamonas testosteroni) were successfully isolated from the enrichment culture inoculated with aerobic activated sludge. To our best knowledge, this is the first report on the biodegradation products and degrading bacteria for norgestrel under aerobic conditions. PMID:23952780

  5. Treatment of industrial effluents by a continuous system: electrocoagulation--activated sludge.

    PubMed

    Moisés, Tejocote-Pérez; Patricia, Balderas-Hernández; Barrera-Díaz, C E; Gabriela, Roa-Morales; Natividad-Rangel, Reyna

    2010-10-01

    A continuous system electrocoagulation--active sludge was designed and built for the treatment of industrial wastewater. The system included an electrochemical reactor with aluminum electrodes, a clarifier and a biological reactor. The electrochemical reactor was tested under different flowrates (50, 100 and 200 mL/min). In the biological reactor, the performance of different cultures of active sludge was assessed: coliform bacterial, ciliate and flagellate protozoa and aquatic fungus. Overall treatment efficiencies of color, turbidity and COD removal were 94%, 92% and 80%, respectively, under optimal conditions of 50 mL/min flowrate and using ciliate and flagellate protozoa. It was concluded that the system was efficient for the treatment of industrial wastewater. PMID:20570506

  6. Newly isolated alkalophilic Advenella species bioaugmented in activated sludge for high p-cresol removal.

    PubMed

    Xenofontos, Eleni; Tanase, Ana-Maria; Stoica, Ileana; Vyrides, Ioannis

    2016-03-25

    In this work, an alkalophilic bacterium (LVX-4) capable of using p-cresol as sole source of carbon and energy was screened and isolated from soil polluted by used oil. Phylogenetic (16S rRNA) and phenotypic characterization using Biolog GN microplates and API 20NE strips indicated that LVX-4 strain is a new Advenella species. It showed both the capability to degrade of p-cresol at high concentrations (750 mg/L) and to use p-cresol for growth in a pH from 7 to 10, although the optimum pH was 9. Moreover bioaugmentation of activated sludge with this strain lead to the complete removal of p-cresol in less than 100 h. This is the first study that shows the potential of Advenella sp. to be bioaugmented in activated sludge system for p-cresol biodegradation. PMID:26596887

  7. New mechanistically based model for predicting reduction of biosolids waste by ozonation of return activated sludge.

    PubMed

    Isazadeh, Siavash; Feng, Min; Urbina Rivas, Luis Enrique; Frigon, Dominic

    2014-04-15

    Two pilot-scale activated sludge reactors were operated for 98 days to provide the necessary data to develop and validate a new mathematical model predicting the reduction of biosolids production by ozonation of the return activated sludge (RAS). Three ozone doses were tested during the study. In addition to the pilot-scale study, laboratory-scale experiments were conducted with mixed liquor suspended solids and with pure cultures to parameterize the biomass inactivation process during exposure to ozone. The experiments revealed that biomass inactivation occurred even at the lowest doses, but that it was not associated with extensive COD solubilization. For validation, the model was used to simulate the temporal dynamics of the pilot-scale operational data. Increasing the description accuracy of the inactivation process improved the precision of the model in predicting the operational data. PMID:24572272

  8. Expression and transfer of engineered catabolic pathways harbored by Pseudomonas spp. introuduced into activated sludge microcosms

    SciTech Connect

    Nublein, K.; Maris, D.; Timmis, K.; Dwyer, D.F. )

    1992-10-01

    Two genetically engineered microorganisms (GEMs), Pseudomonas sp. strain B13 FR1(pFRC20P) (FR120) and Pseudomonas putida KT2440(pWWO-EB62) (EB62), were introduced into activated sludge microcosms that had the level of aeration, nutrient makeup, and microbial community structure of activated sludge reactors. FR120 contains an experimentally assembled ortho cleavage route for simultaneous degradation of 3-chlorobenzoate (3CB) and 4-methyl benzoate (4MB); EB62 contains a derivative TOL plasmid-encoded degradative pathway for toluene experimentally evolved so that it additionally processes 4-ethyl benzoate (4EB). Experiments assessed survival of the GEMs, their ability to degrade target substrates, and lateral transfer of plasmid-encoded recombinant DNA.

  9. Study of the sludge reduction in an oxic-settling-anaerobic activated sludge process based on UNITANK.

    PubMed

    Sun, L P; Chen, J F; Guo, W Z; Fu, X P; Tan, J X; Wang, T J

    2015-01-01

    An oxic-settling-anaerobic process (OSA) can effectively reduce sludge production, but most of the research studies on the OSA process have been either under laboratory test conditions or based on synthetic wastewater, which cannot fully reflect the performance and sludge reduction efficiency in existing OSA process. Thus, aiming at examining the sludge reduction efficiency and the stability of the OSA process, UNITANK and UNITANK-OSA processes were performed in a 120 m(3)/d pilot-scale system using actual sewage. The results indicate that UNITANK-OSA achieved a 48% reduction of the sludge compared to the reduction due to UNITANK, not considering the accumulation of the effluent-suspended solids. The effluent quality was not found to change significantly, except that the total phosphorus concentration increased slightly. The extracellular polymeric substances metal floc theory may, to some extent, explain this reduction in this study. The OSA process could be used to reform the classic wastewater treatment process to get lower sludge mass. PMID:25607677

  10. Granulation of simultaneous partial nitrification and anammox biomass in one single SBR system.

    PubMed

    Li, Xiaoming; Xiao, Yang; Liao, Dexiang; Zheng, Wei; Yi, Ting; Yang, Qi; Zeng, Guangming

    2011-04-01

    The granulation of simultaneous partial nitrification and anaerobic ammonium oxidation (Anammox) was investigated in a single, oxygen-limited, sequencing batch reactor. In this research, the reactor was started anaerobically and fed using the synthetic medium described by Van de Graaf et al. to cultivate Anammox biomass after inoculation with methanogenic granular sludge. Subsequently, mixture gas (air and nitrogen gas) was supplied to the reactor and a nitrifying population developed. Research results indicated that autotrophic granules was cultivated successfully by controlling the dissolved oxygen in the reactor between 0.3 and 0.5 mg/L, and a total inorganic nitrogen removal efficiency of 63.7% was obtained with a higher nitrogen load increased by reducing HRT to 3 days. It was also seen that the Ca and P concentrations of the feeding medium are important factors that influence the autotrophic granules from process running. When the Ca and P concentrations were exceeded the necessary quantity, salt precipitation was observed, interfered with microbial activity, and caused a decrease of the nitrogen removal rate of the system. After diminishing adequately the Ca and P concentrations, salt precipitation was avoided and the activity of the system restored quickly. Moreover, visual indication and scanning election microscopy observation revealed the process of sludge evolution and inner structure of the granules. PMID:21038088

  11. Simple method for the measurement of the hydrogenotrophic methanogenic activity of anaerobic sludges

    USGS Publications Warehouse

    Coates, J.D.; Coughlan, M.F.; Colleran, E.

    1996-01-01

    The specific hydrogenotrophic activity of anaerobic sludges is usually assayed by gas chromatographic analysis for methane in the headspace of sealed test vials. Gas is sampled with a pressure lock syringe which allows quantification independent of the pressure prevailing in the vials. An alternative method was developed using pressure transducer monitoring of the decrease in headspace gas pressure as the H2/CO2 substrate is converted to CH4. Application of a simple formula related the decrease at each sample point to millilitres of CH4 produced and gave values for the specific hydrogenotrophic activity of granular anaerobic sludge which were in good agreement with the values obtained by the more labor-intensive gas chromatographic method. The simplicity of the method facilitates multiple replicate analyses and allows more accurate determination of initial rates than is achievable by the gas chromatographic method which is prone to analytical error at the very low concentrations of CH4 present in the headspace during the early stages of the assay. Mass transfer of H2 from headspace to liquid was found to be rate-limiting and to result in significant under-estimation of the specific hydrogenotrophic activity of the granular sludge. A test protocol, which used a vial volatile suspended solids concentration between 1.7 and 8 g l-1; a 1:5 ratio between liquid and headspace; incubation of the vials horizontally with vigorous shaking (180 rev./min) and an initial H2/CO2 (80/20) gas pressure of 100-150 kPa was found to give reproducible and maximal values for the specific hydrogenotrophic activity of the test sludge.

  12. ALUM ADDITION AND STEP-FEED STUDIES IN OXYGEN-ACTIVATED SLUDGE

    EPA Science Inventory

    A plug flow, O2-activated sludge process was operated with alum addition to remove phosphorus and with lime addition to prevent the process pH from decreasing below 6.4. The O2 reactor was operated at F/M ratios between 0.18 to 0.24 gm of BOD5/gm of MLVSS/day in a typical co-curr...

  13. Insights into the amplification of bacterial resistance to erythromycin in activated sludge.

    PubMed

    Guo, Mei-Ting; Yuan, Qing-Bin; Yang, Jian

    2015-10-01

    Wastewater treatment plants are significant reservoirs for antimicrobial resistance. However, little is known about wastewater treatment effects on the variation of antibiotic resistance. The shifts of bacterial resistance to erythromycin, a macrolide widely used in human medicine, on a lab-scale activated sludge system fed with real wastewater was investigated from levels of bacteria, community and genes, in this study. The resistance variation of total heterotrophic bacteria was studied during the biological treatment process, based on culture dependent method. The alterations of bacterial community resistant to erythromycin and nine typical erythromycin resistance genes were explored with molecular approaches, including high-throughput sequencing and quantitative polymerase chain reaction. The results revealed that the total heterotrophs tolerance level to erythromycin concentrations (higher than 32 mg/L) was significantly amplified during the activated sludge treatment, with the prevalence increased from 9.6% to 21.8%. High-throughput sequencing results demonstrated an obvious increase of the total heterotrophic bacterial diversity resistant to erythromycin. Proteobacteria and Bacteroidetes were the two dominant phyla in the influent and effluent of the bioreactor. However, the prevalence of Proteobacteria decreased from 76% to 59% while the total phyla number increased greatly from 18 to 29 through activated sludge treatment. The gene proportions of erm(A), mef(E) and erm(D) were greatly amplified after biological treatment. It is proposed that the transfer of antibiotic resistance genes through the variable mixtures of bacteria in the activated sludge might be the reason for the antibiotic resistance amplification. The amplified risk of antibiotic resistance in wastewater treatment needs to be paid more attention. PMID:25957255

  14. The efficiency of different phenol-degrading bacteria and activated sludges in detoxification of phenolic leachates.

    PubMed

    Kahru, A; Reiman, R; Rätsep, A

    1998-07-01

    Phenolic composition, toxicity and biodegradability of three different phenolic leachates/samples was studied. Samples A and C were the leachates from the oil-shale industry spent shale dumps at Kohtla-Järve, Estonia. Sample B was a laboratory-prepared synthetic mixture of 7 phenolic compounds mimmicking the phenolic composition of the leachate A. Toxicity of these 3 samples was analyzed using two photobacterial test (BioTox and Microtox), Daphnia test (DAPHTOXKIT F pulex) and rotifiers' test (ROTOXKIT F). All the LC50 values were in the range of 1-10%, leachate A being the most toxic. The growth and detoxifying potential (toxicity of the growth medium was measured using photobacterial tests) of 3 different phenol-utilizing bacteria and acclimated activated sludges was studied in shake-flask cultures. 30% leachate A (altogether 0.6 mM total phenolic compounds) was too toxic to rhodococci and they did not grow. Cell number of Kurthia sp. and Pseudomonas sp. in 30% leachate A increased by 2 orders of magnitude but despite of the growth of bacteria the toxicity of the leachate did not decrease even by 7 weeks of cultivation. However, if the activated sludge was used instead of pure bacterial cultures the toxicity of the 30% leachate A was eliminated already after 3 days of incubation. 30% samples B and C were detoxified by activated sludge even more rapidly, within 2 days. As the biodegradable part of samples A and B should be identical, the detoxification of leachate A compared to that of sample B was most probably inhibited by inorganic (e.g. sulphuric) compounds present in the leachate A. Also, the presence of toxic recalcitrant organic compounds in the leachate A (missed by chemical analysis) that were not readily biodegradable even by activated sludge consortium should not be excluded. PMID:9650267

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

    SciTech Connect

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

    1983-02-01

    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.

  16. The activated sludge ecosystem contains a core community of abundant organisms

    PubMed Central

    Saunders, Aaron M; Albertsen, Mads; Vollertsen, Jes; Nielsen, Per H

    2016-01-01

    Understanding the microbial ecology of a system requires that the observed population dynamics can be linked to their metabolic functions. However, functional characterization is laborious and the choice of organisms should be prioritized to those that are frequently abundant (core) or transiently abundant, which are therefore putatively make the greatest contribution to carbon turnover in the system. We analyzed the microbial communities in 13 Danish wastewater treatment plants with nutrient removal in consecutive years and a single plant periodically over 6 years, using Illumina sequencing of 16S ribosomal RNA amplicons of the V4 region. The plants contained a core community of 63 abundant genus-level operational taxonomic units (OTUs) that made up 68% of the total reads. A core community consisting of abundant OTUs was also observed within the incoming wastewater to three plants. The net growth rate for individual OTUs was quantified using mass balance, and it was found that 10% of the total reads in the activated sludge were from slow or non-growing OTUs, and that their measured abundance was primarily because of immigration with the wastewater. Transiently abundant organisms were also identified. Among them the genus Nitrotoga (class Betaproteobacteria) was the most abundant putative nitrite oxidizer in a number of activated sludge plants, which challenges previous assumptions that Nitrospira (phylum Nitrospirae) are the primary nitrite-oxidizers in activated sludge systems with nutrient removal. PMID:26262816

  17. Biodegradation of various molecular weights of linear polyethylene glycol (PEG) in activated sludge

    SciTech Connect

    Hansmann, M.A.; Bookland, E.A.; Keough, T.W.; Larson, R.J.

    1995-12-31

    Linear polyethylene glycols (PEG) of various average molecular weights (PEG 1000, PEG 3400, PEG 8000, PEG 20000) were tested in a semi-continuous activated sludge test (SCAS), followed by a CO{sub 2} production test to determine which MWs are inherently biodegradable. Complete biodegradation was confirmed analytically using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI TOF MS). The SCAS test estimates the removal of the test substance during wastewater treatment in activated sludge. SCAS removal, as measured by soluble organic carbon (SOC) was > 90% for the PEG 1000, PEG 3400, and PEG 8000, while PEG 20000 showed a SCAS removal of 28%. These results indicate that SCAS removal was largely due to degradation. The CO{sub 2} production test measures the mineralization of the test substance using activated sludge from the SCAS units as the inoculum. The CO{sub 2} test results show that PEG 1000, PEG 3400, and PEG 8000 are inherently biodegradable, with an average %TC02 > 80% by day 50 and remaining SOC < 10% as measured at day 50. Complete loss of material was confirmed by MALDI TOF MS. The PEG 20000 showed 40% TCO2 by day 50, with 50% SOC remaining. MALDI TOF MS confirmed the presence of parent material. Based on these results, PEGs of MW 8000 and less appear to be biodegradable.

  18. Factors influencing sorption of ciprofloxacin onto activated sludge: experimental assessment and modelling implications.

    PubMed

    Polesel, Fabio; Lehnberg, Kai; Dott, Wolfgang; Trapp, Stefan; Thomas, Kevin V; Plósz, Benedek Gy

    2015-01-01

    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 and described, particularly for zwitterionic chemicals. Here we present an assessment of the effects of pH and iron salt dosing on the sorption of ciprofloxacin onto activated sludge using laboratory experiments and full-scale fate modelling. Experimental results were described with Freundlich isotherms and showed that non-linear sorption occurred under all the conditions tested. The greatest sorption potential was measured at pH=7.4, at which ciprofloxacin is speciated mostly as zwitterion. Iron salt dosing increased sorption under aerobic and, to a lesser extent, anoxic conditions, whereas no effect was registered under anaerobic conditions. The activated sludge model for xenobiotics (ASM-X) was extended with Freundlich-based sorption kinetics and used to predict the fate of ciprofloxacin in a wastewater treatment plant (WWTP). Scenario simulations, using experimental Freundlich parameters, were used to identify whether the assessed factors caused a significant increase of aqueous ciprofloxacin concentration in full-scale bioreactors. Simulation results suggest that a pH increase, rather than a reduction in iron salt dosing, could be responsible for a systematic deterioration of sorption of ciprofloxacin in the WWTP. PMID:24972177

  19. Performance of phenol-acclimated activated sludge in the presence of various phenolic compounds

    NASA Astrophysics Data System (ADS)

    Lim, Jun-Wei; Tan, Je-Zhen; Seng, Chye-Eng

    2013-06-01

    The objective of this study was to evaluate the performance of phenol-acclimated activated sludge in the presence of various phenolic compounds in the separated batch reactors. The phenol-acclimated activated sludge was observed to be capable of completely removing phenol, o-cresol, m-cresol, and 4-chlorophenol. Nevertheless, in the presence of 2-chlorophenol and 3-chlorophenol merely at 50 mg/L, incomplete removal of these phenolic compounds were noticed. The specific oxygen uptake rate patterns obtained for phenol, o-cresol, m-cresol, and 4-chlorophenol could be used to approximate the end point of these phenolic compounds removal as well as to monitor the growth of biomass. As the 2-chlorophenol and 3-chlorophenol were only partially removed in the mixed liquor, the patterns of specific oxygen uptake rate attained for these phenolic compounds were not feasible for the similar estimation. The calculated toxicity percentages show the toxicity effects of phenolic compounds on the phenol-acclimated activated sludge followed the order of 2-chlorophenol ≈ 3-chlorophenol > 4-chlorophenol > o-cresol ≈ m-cresol > phenol.

  20. ASExpert: an integrated knowledge-based system for activated sludge plants.

    PubMed

    Sorour, M T; Bahgat, L M F; El, Iskandarani M A; Horan, N J

    2002-08-01

    The activated sludge process is commonly used for secondary wastewater treatment worldwide. This process is capable of achieving high quality effluent. However it has the reputation of being difficult to operate because of its poorly understood biological behaviour, variability of input flows and the need to incorporate qualitative data. To augment this incomplete knowledge with experience, knowledge-based systems were introduced in the 1980s however they didn't receive much popularity. This paper presents the Activated Sludge Expert system (ASExpert), which is a rule-based expert system plus a complete database tool proposed for use in activated sludge plants. The paper focuses on presenting the system's main features and capabilities to revive the interest in knowledge-based systems as a reliable means for monitoring plants. Then it presents the methodology adopted for ASExpert validation along with an assessment of testing results. Finally it concludes that expert systems technology has proved its importance for enhancing performance, especially if in the future it is integrated to a modern control system. PMID:12211453

  1. Cultivation of a bacterial consortium with the potential to degrade total petroleum hydrocarbon using waste activated sludge.

    PubMed

    Sivakumar, S; Song, Y C; Kim, S H; Jang, S H

    2015-11-01

    Waste activated sludge was aerobically treated to demonstrate multiple uses such as cultivating an oil degrading bacterial consortium; studying the influence of a bulking agent (peat moss) and total petroleum hydrocarbon concentration on bacterial growth and producing a soil conditioner using waste activated sludge. After 30 days of incubation, the concentration of oil-degrading bacteria was 4.3 x 10(8) CFU g(-1) and 4.5 x 10(8) CFU g(-1) for 5 and 10 g of total petroleum hydrocarbon, respectively, in a mixture of waste activated sludge (1 kg) and peat moss (0.1 kg). This accounts for approximately 88.4 and 91.1%, respectively, of the total heterotrophic bacteria (total-HB). The addition of bulking agent enhanced total-HB population and total petroleum hydrocarbon-degrading bacterial population. Over 90% of total petroleum hydrocarbon degradation was achieved by the mixture of waste activated sludge, bulking agent and total petroleum hydrocarbon. The results of physico-chemical parameters of the compost (waste activated sludge with and without added peat moss compost) and a substantial reduction in E. coli showed that the use of this final product did not exhibit risk when used as soil conditioner. Finally, the present study demonstrated that cultivation of total petroleum hydrocarbon-degrading bacterial consortium and production of compost from waste activated sludge by aerobic treatment was feasible. PMID:26688976

  2. Measuring the activities of higher organisms in activated sludge by means of mechanical shearing pretreatment and oxygen uptake rate.

    PubMed

    Hao, Xiaodi; Wang, Qilin; Cao, Yali; van Loosdrecht, Mark C M

    2010-07-01

    A pretreatment method was developed to assess the activities of higher organisms. The method is based on mechanical shearing to damage the large cells of the protozoan and metazoan community in activated sludge. The procedure was confirmed through experimentation to be effective in determining the activities of higher organisms by comparing oxygen uptake rates (OURs) before and after the higher organisms were eradicated. Shearing led to disintegration of flocs, which could be effectively reconstituted by centrifugation. The reconstitution of the sludge flocs was essential since otherwise the activity of the floc mass would be too high due to lack of diffusion limitation. Mechanical shearing had no influence on the morphology, quantity and specific activity of yeasts, and it was inferred that bacteria smaller than yeasts in size would also not be influenced by the applied shearing procedure. Moreover, the effect of filamentous organisms on the measured activities of higher organisms was experimentally demonstrated and analyzed, and determined to be so weak that it could be ignored. Based on these tests, five typical activated sludge processes were selected to measure the contribution of higher organisms to the original OUR. The measured activities of higher organisms ranged from 9.4 to 25.0% of the original OURs. PMID:20605188

  3. Stepwise calibration of the activated sludge model no. 1 at a partially denitrifying large wastewater treatment plant.

    PubMed

    Fall, C; Espinosa-Rodriguez, M A; Flores-Alamo, N; van Loosdrecht, M C M; Hooijmans, C M

    2011-11-01

    Activated sludge modeling technology is maturing; however, currently, there exists a great need to increase its use in daily engineering practice worldwide. A good way for building the capacities of the practitioners is to promote good modeling practices and standardize the protocols. In this study, a systematic procedure was proposed to calibrate the Activated Sludge Model No. 1 (ASM1) at a large wastewater treatment plant, by which the model adequately predicted the quality of the effluent and the sludge quantities. A hydraulics model was set up and validated through a tracer test. The Vesilind settling constants were measured and combined with the default value of the flocculent zone settling parameter, to calibrate the clarifiers. A virtual anoxic tank was installed in the return activated sludge to mimic the denitrification occurring in the settlers. In ASM1, the calibrated parameters were only two influent chemical oxygen demand fractions and one kinetic constant (oxygen half-saturation coefficient). PMID:22195426

  4. Microbial Community Dynamics and Activity Link to Indigo Production from Indole in Bioaugmented Activated Sludge Systems

    PubMed Central

    Deng, Jie; Deng, Ye; Van Nostrand, Joy D.; Wu, Liyou; He, Zhili; Qin, Yujia; Zhou, Jiti; Zhou, Jizhong

    2015-01-01

    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 < 0.001) but not in later stages (30–132 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

  5. Enhancement of anaerobic biohydrogen/methane production from cellulose using heat-treated activated sludge.

    PubMed

    Lay, C H; Chang, F Y; Chu, C Y; Chen, C C; Chi, Y C; Hsieh, T T; Huang, H H; Lin, C Y

    2011-01-01

    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. PMID:21902022

  6. Sorption and Release of Organics by Primary, Anaerobic, and Aerobic Activated Sludge Mixed with Raw Municipal Wastewater

    PubMed Central

    Modin, Oskar; Saheb Alam, Soroush; Persson, Frank; Wilén, Britt-Marie

    2015-01-01

    New activated sludge processes that utilize sorption as a major mechanism for organics removal are being developed to maximize energy recovery from wastewater organics, or as enhanced primary treatment technologies. To model and optimize sorption-based activated sludge processes, further knowledge about sorption of organics onto sludge is needed. This study compared primary-, anaerobic-, and aerobic activated sludge as sorbents, determined sorption capacity and kinetics, and investigated some characteristics of the organics being sorbed. Batch sorption assays were carried out without aeration at a mixing velocity of 200 rpm. Only aerobic activated sludge showed net sorption of organics. Sorption of dissolved organics occurred by a near-instantaneous sorption event followed by a slower process that obeyed 1st order kinetics. Sorption of particulates also followed 1st order kinetics but there was no instantaneous sorption event; instead there was a release of particles upon mixing. The 5-min sorption capacity of activated sludge was 6.5±10.8 mg total organic carbon (TOC) per g volatile suspend solids (VSS) for particulate organics and 5.0±4.7 mgTOC/gVSS for dissolved organics. The observed instantaneous sorption appeared to be mainly due to organics larger than 20 kDa in size being sorbed, although molecules with a size of about 200 Da with strong UV absorbance at 215–230 nm were also rapidly removed. PMID:25768429

  7. Sorption and release of organics by primary, anaerobic, and aerobic activated sludge mixed with raw municipal wastewater.

    PubMed

    Modin, Oskar; Saheb Alam, Soroush; Persson, Frank; Wilén, Britt-Marie

    2015-01-01

    New activated sludge processes that utilize sorption as a major mechanism for organics removal are being developed to maximize energy recovery from wastewater organics, or as enhanced primary treatment technologies. To model and optimize sorption-based activated sludge processes, further knowledge about sorption of organics onto sludge is needed. This study compared primary-, anaerobic-, and aerobic activated sludge as sorbents, determined sorption capacity and kinetics, and investigated some characteristics of the organics being sorbed. Batch sorption assays were carried out without aeration at a mixing velocity of 200 rpm. Only aerobic activated sludge showed net sorption of organics. Sorption of dissolved organics occurred by a near-instantaneous sorption event followed by a slower process that obeyed 1st order kinetics. Sorption of particulates also followed 1st order kinetics but there was no instantaneous sorption event; instead there was a release of particles upon mixing. The 5-min sorption capacity of activated sludge was 6.5±10.8 mg total organic carbon (TOC) per g volatile suspend solids (VSS) for particulate organics and 5.0±4.7 mgTOC/gVSS for dissolved organics. The observed instantaneous sorption appeared to be mainly due to organics larger than 20 kDa in size being sorbed, although molecules with a size of about 200 Da with strong UV absorbance at 215-230 nm were also rapidly removed. PMID:25768429

  8. Epilithic biofilms as hotspots of in-stream nitrification in a high N loaded urban stream

    NASA Astrophysics Data System (ADS)

    Bernal, S.; Merbt, S. N.; Ribot, M.; Casamayor, E. O.; Martí Roca, E.

    2015-12-01

    Nitrification, the oxidation of ammonia to nitrate, is one of the most important biogeochemical processes in high nitrogen loaded urban streams. The first rate-limiting step of the nitrification process is carried out by ammonia-oxidizing (AO) archaea (AOB) and bacteria (AOB) that live in stream sediments and epilithic biofilms. Yet, the relative contribution of these two stream habitats to whole-reach nitrification is largely unknown. We tested the well-established idea that whole-reach nitrification is mainly driven by AO present in hyporheic sediments because of their relative high active surface area compared to the thin epilithic biofilm interface. To do so, we examined substrata-specific nitrification rates and AO transcripts abundance (amoA gene) in mesocosms and scaled data to whole reach. Further, we compared the scaled data to in situ whole-reach nitrification rates and amoA transcript and gene abundances in a high N loaded urban stream downstream of a waste water treatment plant effluent. Against expectations, whole-reach in-stream nitrification was mainly driven by AOB embedded in biofilms growing on the sediment-facing side (> 60%) and light-exposed side (20%) of stream cobbles. Hyporheic sediments, which were mainly colonized by AOA, accounted for 11% of in situ whole-reach nitrification. Our study points epilithic biofilms as hot spots of nitrification within urban stream ecosystems.

  9. Effect of acclimation and nutrient supply on 5-tolyltriazole biodegradation with activated sludge communities.

    PubMed

    Herzog, Bastian; Yuan, Heyang; Lemmer, Hilde; Horn, Harald; Müller, Elisabeth

    2014-07-01

    The corrosion inhibitor 5-tolyltriazole (5-TTri) can have a detrimental impact on aquatic systems thus implying an acute need to reduce the effluent concentrations of 5-TTri. In this study, 5-TTri biodegradation was enhanced through acclimation and nutrient supply. Activated sludge communities (ASC) were setup in nine subsequent ASC generations. While generation two showed a lag phase of five days without biodegradation, generations four to nine utilized 5-TTri right after inoculation, with biodegradation rates from 3.3 to 5.2 mg L(-1)d(-1). Additionally, centrifuged AS supernatant was used to simulate the nutrient conditions in wastewater. This sludge supernatant (SS) significantly enhanced biodegradation, resulting in removal rates ranging from 3.2 to 5.0 mg L(-1)d(-1) without acclimation while the control groups without SS observed lower rates of ⩽ 2.2 mg L(-1)d(-1). PMID:24841493

  10. Effect of Worm Predation on Changes in Waste Activated Sludge Properties.

    PubMed

    Zhu, Xuefeng; Yuan, Wenyi; Wang, Zhiwei; Zhou, Mingyuan; Guan, Jie

    2016-05-01

    This study explored the effects of worm predation on changes in waste activated sludge properties. Results showed that the rate by which worm predation reduced mixed liquor volatile suspended solids (MLVSS) was approximately 23.7% ± 3.1%. Particle size distribution and extracellular polymeric substance (EPS) analyses indicated that the reduction of fine particles and EPS content in sludge predated by worms mainly increased dewaterability and reduced the ratio of MLVSS/mixed liquor suspended solids. Moreover, both mean particle size and protein/carbohydrate ratio increased. The results of three-dimensional excitation-emission matrix and gel filtration chromatogram analyses demonstrated the varied properties of soluble microbial products and EPS were attributed to the worms' selective predation of low molecular-weight organic matter, which facilitated the hydrolysis of macromolecular organic matter. PMID:27131302

  11. Experimental Assessment of the Degradation of "Unbiodegradable" Organic Solids in Activated Sludge.

    PubMed

    Friedrich, M; Takács, I; Tränckner, Jens

    2016-03-01

    In current process models activated sludge consists of biodegradable and unbiodegradable organic fractions. Recent evidence suggests that this approach may not be accurate because some of this "unbiodegradable" material may indeed be degradable. To improve sludge production predictions, it is important to know to what extent the "unbiodegradable" organic fraction is degradable. Assuming that volatile suspended solids (VSS) is a measure of the sum of biodegradable and unbiodegradable organic solids and the integral of the oxygen uptake rate (OUR) is representative of the biodegradable organics, the combination of these measurements can be used to predict the change of unbiodegradable organic solids within an aerobic digestion batch experiment. This procedure was used to estimate degradation rates of "unbiodegradable" VSS between 0.006 to 0.029 d(-1). The advantage of the proposed method is that the degradation rate can be determined directly based on measurements and relies on a limited number of assumptions. PMID:26931538

  12. Hydraulic characterization of an activated sludge reactor with recycling system by tracer experiment and analytical models.

    PubMed

    Sánchez, F; Viedma, A; Kaiser, A S

    2016-09-15

    Fluid dynamic behaviour plays an important role in wastewater treatment. An efficient treatment requires the inexistence of certain hydraulic problems such as dead zones or short-circuiting flows. Residence time distribution (RTD) analysis is an excellent technique for detecting these inefficiencies. However, many wastewater treatment installations include water or sludge recycling systems, which prevent us from carrying out a conventional tracer pulse experiment to obtain the RTD curve of the installation. This paper develops an RTD analysis of an activated sludge reactor with recycling system. A tracer experiment in the reactor is carried out. Three analytical models, derived from the conventional pulse model, are proposed to obtain the RTD curve of the reactor. An analysis of the results is made, studying which model is the most suitable for each situation. This paper is useful to analyse the hydraulic efficiency of reactors with recycling systems. PMID:27288672

  13. Utilization of molasses spentwash for production of bioplastics by waste activated sludge

    SciTech Connect

    Khardenavis, Anshuman A. Vaidya, Atul N.; Kumar, M. Suresh; Chakrabarti, Tapan

    2009-09-15

    Present study describes the treatment of molasses spentwash and its use as a potential low cost substrate for production of biopolymer polyhydroxybutyrate (PHB) by waste activated sludge. Fluorescence microscopy revealed the presence of PHB granules in sludge biomass which was further confirmed by fourier transform-infra-red spectroscopy (FT-IR) and {sup 13}C nuclear magnetic resonance (NMR). The processing of molasses spentwash was carried out for attaining different ratios of carbon and nitrogen (C:N). Highest chemical oxygen demand (COD) removal and PHB accumulation of 60% and 31% respectively was achieved with raw molasses spentwash containing inorganic nitrogen (C:N ratio = 28) followed by COD removal of 52% and PHB accumulation of 28% for filtered molasses containing inorganic nitrogen (C:N ratio = 29). PHB production yield (Y{sub p/s}) was highest (0.184 g g{sup -1} COD consumed) for deproteinized spentwash supplemented with nitrogen. In contrast, the substrate consumption and product formation were higher in case of raw spentwash. Though COD removal was lowest from deproteinized spentwash, evaluation of kinetic parameters suggested higher rates of conversion of available carbon to biomass and PHB. Thus the process provided dual benefit of conversion of two wastes viz. waste activated sludge and molasses spentwash into value-added product-PHB.

  14. Degradation of estradiol and ethinyl estradiol by activated sludge and by a defined mixed culture.

    PubMed

    Weber, Stefanie; Leuschner, Prisca; Kämpfer, Peter; Dott, Wolfgang; Hollender, Juliane

    2005-04-01

    The aerobic degradation of the natural hormone 17-beta-estradiol (E2) and the synthetic hormone 17-alpha-ethinyl estradiol (EE2) was investigated in batch experiments with activated sludge from a conventional and a membrane sewage treatment plant. E2 was converted to estrone (E1), the well known metabolite, and further completely transformed within 3 days. The turnover rates of E2 did not differ greatly between conventional and membrane activated sludge. EE2 was persistent in both sludges. By several transfers into fresh E2-medium an enrichment culture could be selected that used E2 as growth substrate. Further enrichment and isolation led to a defined mixed culture consisting of two strains, which were identified by a polyphasic approach as Achromobacter xylosoxidans and Ralstonia sp., respectively. The culture used E2 and E1 as growth substrates and transformed estriol (E3) and 16-alpha-hydroxyestrone but not the xenoestrogens bisphenol A, alpha-zearalenol, mestranol or EE2. The turnover rates of E2 were 0.025-0.1 microg h(-1) cfu(-1) and did not depend on the steroid concentration. PMID:15290133

  15. Mechanisms involved in Escherichia coli and Serratia marcescens removal during activated sludge wastewater treatment

    PubMed Central

    Orruño, Maite; Garaizabal, Idoia; Bravo, Zaloa; Parada, Claudia; Barcina, Isabel; Arana, Inés

    2014-01-01

    Wastewater treatment reduces environmental contamination by removing gross solids and mitigating the effects of pollution. Treatment also reduces the number of indicator organisms and pathogens. In this work, the fates of two coliform bacteria, Escherichia coli and Serratia marcescens, were analyzed in an activated sludge process to determine the main mechanisms involved in the reduction of pathogenic microorganisms during wastewater treatment. These bacteria, modified to express green fluorescent protein, were inoculated in an activated sludge unit and in batch systems containing wastewater. The results suggested that, among the different biological factors implied in bacterial removal, bacterivorous protozoa play a key role. Moreover, a representative number of bacteria persisted in the system as free-living or embedded cells, but their distribution into liquid or solid fractions varied depending on the bacterium tested, questioning the real value of bacterial indicators for the control of wastewater treatment process. Additionally, viable but nonculturable cells constituted an important part of the bacterial population adhered to solid fractions, what can be derived from the competition relationships with native bacteria, present in high densities in this environment. These facts, taken together, emphasize the need for reliable quantitative and qualitative analysis tools for the evaluation of pathogenic microbial composition in sludge, which could represent an undefined risk to public health and ecosystem functions when considering its recycling. PMID:25044599

  16. Mechanisms involved in Escherichia coli and Serratia marcescens removal during activated sludge wastewater treatment.

    PubMed

    Orruño, Maite; Garaizabal, Idoia; Bravo, Zaloa; Parada, Claudia; Barcina, Isabel; Arana, Inés

    2014-10-01

    Wastewater treatment reduces environmental contamination by removing gross solids and mitigating the effects of pollution. Treatment also reduces the number of indicator organisms and pathogens. In this work, the fates of two coliform bacteria, Escherichia coli and Serratia marcescens, were analyzed in an activated sludge process to determine the main mechanisms involved in the reduction of pathogenic microorganisms during wastewater treatment. These bacteria, modified to express green fluorescent protein, were inoculated in an activated sludge unit and in batch systems containing wastewater. The results suggested that, among the different biological factors implied in bacterial removal, bacterivorous protozoa play a key role. Moreover, a representative number of bacteria persisted in the system as free-living or embedded cells, but their distribution into liquid or solid fractions varied depending on the bacterium tested, questioning the real value of bacterial indicators for the control of wastewater treatment process. Additionally, viable but nonculturable cells constituted an important part of the bacterial population adhered to solid fractions, what can be derived from the competition relationships with native bacteria, present in high densities in this environment. These facts, taken together, emphasize the need for reliable quantitative and qualitative analysis tools for the evaluation of pathogenic microbial composition in sludge, which could represent an undefined risk to public health and ecosystem functions when considering its recycling. PMID:25044599

  17. Application of activated sludge to purify urban soils of Baku city from oil contamination

    NASA Astrophysics Data System (ADS)

    Babaev, M. P.; Nadzhafova, S. I.; Ibragimov, A. G.

    2015-07-01

    A biopreparation inducing oil destruction and increasing the biological activity of soils was developed on the basis of activated sludge. Its oxidative activity towards hydrocarbons was studied. The application of this biopreparation to oil-contaminated soil increased the population density of microorganisms, including destroyers of hydrocarbons, and accelerated oil decomposition. The degree of destruction of oil and oil products in the case of a single treatment of the soil with this biopreparation comprised 30 to 50% within 60 days. The presence of cellulose-decomposing microorganisms in this biopreparation also favored an accelerated decomposition of plant substances, including plant litter and sawdust applied to the urban soils as an adsorbent.

  18. Bioaugmentation of Activated Sludge by an Indigenous 3-Chloroaniline-Degrading Comamonas testosteroni Strain, I2gfp

    PubMed Central

    Boon, Nico; Goris, Johan; De Vos, Paul; Verstraete, Willy; Top, Eva M.

    2000-01-01

    A strain identified as Comamonas testosteroni I2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-CA). During the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. This strain was tested for its ability to clean wastewater containing 3-CA upon inoculation into activated sludge. To monitor its survival, the strain was chromosomally marked with the gfp gene and designated I2gfp. After inoculation into a lab-scale semicontinuous activated-sludge (SCAS) system, the inoculated strain maintained itself in the sludge for at least 45 days and was present in the sludge flocs. After an initial adaptation period of 6 days, complete degradation of 3-CA was obtained during 2 weeks, while no degradation at all occurred in the noninoculated control reactor. Upon further operation of the SCAS system, only 50% 3-CA removal was observed. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes revealed a dynamic change in the microbial community structure of the activated sludge. The DGGE patterns of the noninoculated and the inoculated reactors evolved after 7 days to different clusters, which suggests an effect of strain inoculation on the microbial community structure. The results indicate that bioaugmentation, even with a strain originating from that ecosystem and able to effectively grow on a selective substrate, is not permanent and will probably require regular resupplementation. PMID:10877785

  19. SIMPLIFIED INJECTION OF OXYGEN GAS INTO AN ACTIVATED SLUDGE PROCESS

    EPA Science Inventory

    The Las Virgenes Municipal Water District conducted a pilot investigation of the Simplox process at their Tapia Water Reclamation Facility in Calabasas, California. The Simplox process, developed by the Cosmodyne Division of Cordon International, involves covering an activated sl...

  20. Systematic investigation and microbial community profile of indole degradation processes in two aerobic activated sludge systems

    PubMed Central

    Ma, Qiao; Qu, Yuanyuan; Zhang, Xuwang; Liu, Ziyan; Li, Huijie; Zhang, Zhaojing; Wang, Jingwei; Shen, Wenli; Zhou, Jiti

    2015-01-01

    Indole is widely spread in various environmental matrices. Indole degradation by bacteria has been reported previously, whereas its degradation processes driven by aerobic microbial community were as-yet unexplored. Herein, eight sequencing batch bioreactors fed with municipal and coking activated sludges were constructed for aerobic treatment of indole. The whole operation processes contained three stages, i.e. stage I, glucose and indole as carbon sources; stage II, indole as carbon source; and stage III, indole as carbon and nitrogen source. Indole could be completely removed in both systems. Illumina sequencing revealed that alpha diversity was reduced after indole treatment and microbial communities were significantly distinct among the three stages. At genus level, Azorcus and Thauera were dominant species in stage I in both systems, while Alcaligenes, Comamonas and Pseudomonas were the core genera in stage II and III in municipal sludge system, Alcaligenes and Burkholderia in coking sludge system. In addition, four strains belonged to genera Comamonas, Burkholderia and Xenophilus were isolated using indole as sole carbon source. Burkholderia sp. IDO3 could remove 100 mg/L indole completely within 14 h, the highest degradation rate to date. These findings provide novel information and enrich our understanding of indole aerobic degradation processes. PMID:26657581

  1. Improving Settling Characteristics of Pure Oxygen Activated Sludge by Stripping of Carbon Dioxide.

    PubMed

    Kundral, Somshekhar; Mudragada, Ratnaji; Coro, Ernesto; Moncholi, Manny; Mora, Nelson; Laha, Shonali; Tansel, Berrin

    2015-06-01

    Increased microbial activity at high ambient temperatures can be problematic for secondary clarifiers and gravity concentrators due to carbon dioxide (CO2) production. Production of CO2 in gravity concentrators leads to septic conditions and poor solids separation. The CO2 production can also be corrosive for the concrete surfaces. Effectiveness of CO2 stripping to improve solids settling was investigated using the sludge volume index (SVI) as the indicator parameter. Carbon dioxide was stripped by aeration from the sludge samples. Results from the study show that aeration also increased the pH values in the mixed liquor while removing CO2 and improving sludge settling. After 10 minutes of aeration at a rate of 0.37 m3 air/m3 water/min, 90% CO2 stripping was achieved. Based on the 30 min settling tests, the SVI increased by 26±1% after CO2 stripping while the pH increased by 0.8±0.1 pH units. PMID:26459818

  2. Comparative study of wastewater treatment and nutrient recycle via activated sludge, microalgae and combination systems.

    PubMed

    Wang, Liang; Liu, Jinli; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2016-07-01

    Algal-bacterial synergistic cultivation could be an optional wastewater treatment technology in temperate areas. In this study, a locally screened vigorous Chlorella strain was characterized and then it was used in a comparative study of wastewater treatment and nutrient recycle assessment via activated sludge (AS), microalgae and their combination systems. Chlorella sp. cultured with AS in light showed the best performance, in which case the removal efficiencies of COD, NH3-N and TP were 87.3%, 99.2% and 83.9%, respectively, within a short period of 1day. Algal-bacterial combination in light had the best settleability. Chlorella sp. contained biomass, could be processed to feed, fertilizer or fuel due to the improved quality (higher C/H/N) compared with sludge. PCR-DGGE analysis shows that two types of rhizobacteria, namely, Pseudomonas putida and Flavobacterium hauense were enriched in sludge when cultured with algae in light, serving as the basics for artificial consortium construction for improved wastewater treatment. PMID:26995615

  3. Effects of microwave irradiation on dewaterability and extracellular polymeric substances of waste activated sludge.

    PubMed

    Peng, Ge; Ye, Fenxia; Ye, Yangfang

    2013-03-01

    The effects of microwave irradiation on filterability and dewaterability of waste activated sludge measured by capillary suction time (CST) and dry solids in sludge cake were investigated. The results showed that the optimum irradiation time improved filterability, but that further increase of the time was detrimental. Dewaterability was enhanced significantly and increased with microwave time. Filterability and dewaterability were improved 25 to 28% and 1.3 times at the optimum times of 30 and 90 seconds for the sludge of 5 g total suspended solids (TSS)/L and 7 g TSS/L, respectively. The floc size decreased slightly. Loosely bound extracellular polymeric substances (LB-EPS) decreased under optimum time, but tightly bound extracellular polymeric substances did not change significantly after short irradiation time. The results implied that LB-EPS played a more important role in the observed changes of filterability and dewaterability and that the double-layered extracellular polymeric substances extraction method showed marked implications to dewaterability. PMID:23581243

  4. Biological short-chain fatty acids (SCFAs) production from waste-activated sludge affected by surfactant.

    PubMed

    Jiang, Su; Chen, Yinguang; Zhou, Qi; Gu, Guowei

    2007-07-01

    Short-chain fatty acids (SCFAs), the preferred carbon sources for biological nutrient removal, are the important intermediate products in sludge anaerobic fermentation. Sodium dodecylbenzene sulfonate (SDBS) is a widespread used surfactant, which can be easily found in waste-activated sludge (WAS). In this investigation, the effect of SDBS on SCFAs production from WAS was investigated, and the potential of using fermentative SCFAs to promote enhanced biological phosphorus removal (EBPR) was tested. Results showed that the total SCFAs production increased significantly in the presence of SDBS at room temperature. At fermentation time of 6 days, the maximum SCFAs was 2599.1mg chemical oxygen demand (COD)/L in the presence of SDBS 0.02g/g, whereas it was only 339.1mg (COD)/L in the absence of SDBS. The SCFAs produced in the case of SDBS 0.02g/g and fermentation time 6 days consisted of acetic acid (27.1%), propionic acid (22.8%), iso-valeric acid (20.1%), iso-butyric acid (11.9%), n-butyric acid (10.4%) and n-valeric acid (7.7%). It was found that during sludge anaerobic fermentation, the solubilization of sludge particulate organic-carbon and hydrolysis of solubilized substrate as well as acidification of hydrolyzed products were all increased in the presence of SDBS, while the methane formation was decreased, the SCFAs production was therefore remarkably improved. Further investigation showed that the production of SCFAs enhanced by SDBS was caused mainly by biological effects, rather than by chemical effects and SDBS decomposition. With the fermentative SCFAs as the main carbon source, the EBPR maintained high phosphorus removal efficiency ( approximately 97%). PMID:17499838

  5. Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature-Size Rule

    PubMed Central

    Kiełbasa, Anna; Walczyńska, Aleksandra; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kozłowski, Jan

    2014-01-01

    Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifers to seasonally change their body size according to TSR, and that oxygen content also induces the size response. The presence of TSR in Lecane inermis rotifer was tested in a laboratory study with two temperature and two food-type treatments. The effect of interaction between temperature and food was significant; L. inermis followed TSR in one food type only. The seasonal variability in the body sizes of the rotifers L. inermis and Cephalodella gracilis was estimated by monthly sampling and analyzed by multiple regression, in relation to the sludge parameters selected as the most influential by multivariate analysis, and predicted to alter rotifer body size (temperature and oxygen). L. inermis varied significantly in size throughout the year, and this variability is explained by temperature as predicted by the TSR, but not by oxygen availability. C. gracilis also varied in size, though this variability was explained by both temperature and oxygen. We suggest that sludge age acts as a mortality factor in activated sludge. It may have a seasonal effect on the body size of L. inermis and modify a possible effect of oxygen. Activated sludge habitat is driven by both biological processes and human regulation, yet its resident organisms follow general evolutionary rule as they do in other biological systems. The interspecific response patterns differ, revealing the importance of taking species-specific properties into account. Our findings are applicable to sludge properties enhancement through optimizing the conditions for its biological component. PMID:25558362

  6. Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature-Size Rule.

    PubMed

    Kiełbasa, Anna; Walczyńska, Aleksandra; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kozłowski, Jan

    2014-12-01

    Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifers to seasonally change their body size according to TSR, and that oxygen content also induces the size response. The presence of TSR in Lecane inermis rotifer was tested in a laboratory study with two temperature and two food-type treatments. The effect of interaction between temperature and food was significant; L. inermis followed TSR in one food type only. The seasonal variability in the body sizes of the rotifers L. inermis and Cephalodella gracilis was estimated by monthly sampling and analyzed by multiple regression, in relation to the sludge parameters selected as the most influential by multivariate analysis, and predicted to alter rotifer body size (temperature and oxygen). L. inermis varied significantly in size throughout the year, and this variability is explained by temperature as predicted by the TSR, but not by oxygen availability. C. gracilis also varied in size, though this variability was explained by both temperature and oxygen. We suggest that sludge age acts as a mortality factor in activated sludge. It may have a seasonal effect on the body size of L. inermis and modify a possible effect of oxygen. Activated sludge habitat is driven by both biological processes and human regulation, yet its resident organisms follow general evolutionary rule as they do in other biological systems. The interspecific response patterns differ, revealing the importance of taking species-specific properties into account. Our findings are applicable to sludge properties enhancement through optimizing the conditions for its biological component. PMID:25558362

  7. Automatic set-point titration for monitoring nitrification in SBRs.

    PubMed

    Fiocchi, N; Ficara, E; Bonelli, S; Canziani, R; Ciappelloni, F; Mariani, S; Pirani, M; Ratini, P; Mazouni, D; Harmand, J

    2008-01-01

    Nitrification is usually the bottleneck of biological nitrogen removal processes. In SBRs systems, it is not often enough to monitor dissolved oxygen, pH and ORP to spot problems which may occur in nitrification processes. Therefore, automated supervision systems should be designed to include the possibility of monitoring the activity of nitrifying populations. Though the applicability of set-point titration for monitoring biological processes has been widely demonstrated in the literature, the possibility of an automated procedure is still at its early stage of industrial development. In this work, the use of an at-line automated titrator named TITAAN (TITrimetric Automated ANalyser) is presented. The completely automated sensor enables us to track nitrification rate trend with time in an SBR, detecting the causes leading to slower specific nitrification rates. It was also possible to perform early detection of toxic compounds in the influent by assessing their effect on the nitrifying biomass. Nitrifications rates were determined with average errors+/-10% (on 26 tests), never exceeding 20% as compared with UV-spectrophotometric determinations. PMID:18701782

  8. Metagenomic analyses reveal phylogenetic diversity of carboxypeptidase gene sequences in activated sludge of a wastewater treatment plant in Shanghai, China.

    PubMed

    Jin, Hao; Li, Bailin; Peng, Xu; Chen, Lanming

    2014-01-01

    Activated sludge of wastewater treatment plants carries a diverse microflora. However, up to 80-90 % of microorganisms in activated sludge cannot be cultured by current laboratory techniques, leaving an enzyme reservoir largely unexplored. In this study, we investigated carboxypeptidase diversity in activated sludge of a wastewater treatment plant in Shanghai, China, by a culture-independent metagenomic approach. Three sets of consensus degenerate hybrid oligonucleotide primers (CODEHOPs) targeting conserved domains of public carboxypeptidases have been designed to amplify carboxypeptidase gene sequences in the metagenomic DNA of activated sludge by PCR. The desired amplicons were evaluated by carboxypeptidase sequence clone libraries and phylogenetic analyses. We uncovered a significant diversity of carboxypeptidases present in the activated sludge. Deduced carboxypeptidase amino acid sequences (127-208 amino acids) were classified into three distinct clusters, α, β, and γ. Sequences belonging to clusters α and β shared 58-97 % identity to known carboxypeptidase sequences from diverse species, whereas sequences in the cluster γ were remarkably less related to public carboxypeptidase homologous in the GenBank database, strongly suggesting that novel carboxypeptidase families or microbial niches exist in the activated sludge. We also observed numerous carboxypeptidase sequences that were much closer to those from representative strains present in industrial and sewage treatment and bioremediation. Thermostable and halotolerant carboxypeptidase sequences were also detected in clusters α and β. Coexistence of various carboxypeptidases is evidence of a diverse microflora in the activated sludge, a feature suggesting a valuable gene resource to be further explored for biotechnology application. PMID:24860282

  9. Contribution of stratified extracellular polymeric substances to the gel-like and fractal structures of activated sludge.

    PubMed

    Yuan, D Q; Wang, Y L; Feng, J

    2014-06-01

    The gel-like and fractal structures of activated sludge (AS) before and after extracellular polymeric substances (EPS) extraction as well as different EPS fractions were investigated. The contributions of individual components in different EPS fractions to the gel-like behavior of sludge samples by enzyme treatment were examined as well. The centrifugation and ultrasound method was employed to stratify the EPS into slime, loosely and tightly bound EPS (LB- and TB-EPS). It was observed that all samples behaved as weak gels with weak-link. TB-EPS and AS after LB-EPS extraction showed the strongest elasticity in higher concentrations and highest mass fractal dimension, which may indicate the key role of TB-EPS in the gel-like and fractal structures of the sludge. Effects of protease or amylase on the gel-like property of sludge samples differed in the presence of different EPS fractions. PMID:24651018

  10. Organics removal from landfill leachate and activated sludge production in SBR reactors

    SciTech Connect

    Klimiuk, Ewa; Kulikowska, Dorota . E-mail: dorotak@uwm.edu.pl

    2006-07-01

    This study is aimed at estimating organic compounds removal and sludge production in SBR during treatment of landfill leachate. Four series were performed. At each series, experiments were carried out at the hydraulic retention time (HRT) of 12, 6, 3 and 2 d. The series varied in SBR filling strategies, duration of the mixing and aeration phases, and the sludge age. In series 1 and 2 (a short filling period, mixing and aeration phases in the operating cycle), the relationship between organics concentration (COD) in the leachate treated and HRT was pseudo-first-order kinetics. In series 3 (with mixing and aeration phases) and series 4 (only aeration phase) with leachate supplied by means of a peristaltic pump for 4 h of the cycle (filling during reaction period) - this relationship was zero-order kinetics. Activated sludge production expressed as the observed coefficient of biomass production (Y {sub obs}) decreased correspondingly with increasing HRT. The smallest differences between reactors were observed in series 3 in which Y {sub obs} was almost stable (0.55-0.6 mg VSS/mg COD). The elimination of the mixing phase in the cycle (series 4) caused the Y {sub obs} to decrease significantly from 0.32 mg VSS/mg COD at HRT 2 d to 0.04 mg VSS/mg COD at HRT 12 d. The theoretical yield coefficient Y accounted for 0.534 mg VSS/mg COD (series 1) and 0.583 mg VSS/mg COD (series 2). In series 3 and 4, it was almost stable (0.628 mg VSS/mg COD and 0.616 mg VSS/mg COD, respectively). After the elimination of the mixing phase in the operating cycle, the specific biomass decay rate increased from 0.006 d{sup -1} (series 3) to 0.032 d{sup -1} (series 4). The operating conditions employing mixing/aeration or only aeration phases enable regulation of the sludge production. The SBRs operated under aerobic conditions are more favourable at a short hydraulic retention time. At long hydraulic retention time, it can lead to a decrease in biomass concentration in the SBR as a result of

  11. Correlation between fouling propensity of soluble extracellular polymeric substances and sludge metabolic activity altered by different starvation conditions.

    PubMed

    Wu, Siang Chen; Lee, Chi Mei

    2011-05-01

    Soluble extracellular polymeric substances (EPSs) cause membrane fouling in membrane bioreactors (MBRs), correlated with MBR sludge characteristics. Effects of F/M ratios on the evolution of soluble EPSs, fouling propensity of supernatants, and sludge metabolic activity were measured in this study in a two-period sequencing batch reactor (SBR). The experimental results show that fouling propensity was directly correlated with soluble-EPS concentration and composition. Sludge that had entirely lost active cells by long-term starvation released 64.4 ± 0.9 mg/L of humic acids, which caused a rapid increase in membrane resistance (40.67 ± 2.24 × 10(11) m(-1)) during fouling tests. During short-term starvation, induced by incubation at a normal to low F/M ratio of 0.05 d(-1), sludge can use previously secreted utilization-associated products (UAPs) to maintain endogenous respiration. Therefore, the strategies of accumulating sludge and prolonging sludge retention time in MBRs may create long-term starvation and promote membrane fouling. PMID:21163646

  12. Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment.

    PubMed

    Yang, Shan-Shan; Guo, Wan-Qian; Chen, Yi-Di; Wu, Qing-Lian; Luo, Hai-Chao; Peng, Si-Mai; Zheng, He-Shan; Feng, Xiao-Chi; Zhou, Xu; Ren, Nan-Qi

    2015-02-01

    An ozone/ultrasound lysis-cryptic growth technology combining a continuous flow anaerobic-anoxic-microaerobic-aerobic (AAMA+O3/US) system was investigated. Techno-economic evaluation and sludge lyses return ratio (r) optimization of this AAMA+O3/US system were systematically and comprehensively discussed. Economic assessment demonstrated that this AAMA+O3/US system with r of 30% (AAMA+O3/US2# system) was more economically feasible that can give a 14.04% saving of costs. In addition to economic benefits, a 55.08% reduction in sludge production, and respective 21.17% and 5.45% increases in TN and TP removal efficiencies were observed in this AAMA+O3/US2# system. Considering the process performances and economic benefits, r of 30% in AAMA+O3/US2# system was recommended. Excitation-emission matrix and Fourier transform infrared spectra analyses also proved that less refractory soluble microbial products were generated from AAMA+O3/US2# system. Improvement in 2,3,5-triphenyltetrazolium chloride electron transport system (TTC-ETS) activity in AAMA+O3/US2# further indicated that a lower sludge lyses return ratio stimulated the microbial activity. PMID:25490102

  13. Chemically coupled microwave and ultrasonic pre-hydrolysis of pulp and paper mill waste-activated sludge: effect on sludge solubilisation and anaerobic digestion.

    PubMed

    Tyagi, Vinay Kumar; Lo, Shang-Lien; Rajpal, Ankur

    2014-05-01

    The effects of alkali-enhanced microwave (MW; 50-175 °C) and ultrasonic (US) (0.75 W/mL, 15-60 min) pretreatments, on solubilisation and subsequent anaerobic digestion efficiency of pulp and paper mill waste-activated sludge, were investigated. Improvements in total chemical oxygen demand and volatile suspended solids (VSS) solubilisation were limited to 33 and 39 % in MW pretreatment only (175 °C). It reached 78 and 66 % in combined MW-alkali pretreatment (pH 12 + 175 °C), respectively. Similarly, chemical oxygen demand and VSS solubilisation were 58 and 37 % in US pretreatment alone (60 min) and it improved by 66 and 49 % after US-alkali pretreatment (pH 12 + 60 min), respectively. The biogas yield for US 60 min-alkali (pH 12)-pretreated sludge was significantly improved by 47 and 20 % over the control and US 60 reactors, respectively. The biogas generation for MW (150 °C)-alkali (pH 12)-pretreated sludge was only 6.3 % higher than control; however, it was 8.3 % lower than the MW (150 °C) reactor, which was due to the inhibition of anaerobic activity under harsh thermal-alkali treatment condition. PMID:24488518

  14. Waste activated sludge treatment based on temperature staged and biologically phased anaerobic digestion system.

    PubMed

    Yu, Jingwen; Zheng, Mingxia; Tao, Tao; Zuo, Jiane; Wang, Kaijun

    2013-10-01

    The concept of temperature staged and biological phased (TSBP) was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the effect of temperature (35 to 70 degrees C) as well as the hydraulic retention time (HRT) (2, 4 and 6 days) on the acidogenic phase. The results showed that the solubilization degree of waste-activated sludge increased from 14.7% to 30.1% with temperature increasing from 35 to 70 degrees C, while the acidification degree was highest at 45 degrees C (17.6%), and this was quite different from the temperature impact on hydrolysis. Compared with HRT of 2 and 6 days, 4 days was chosen as the appropriate HRT because of its relatively high solubilization degree (24.6%) and acidification degree (20.1%) at 45 degrees C. The TSBP system combined the acidogenic reactor (45 degrees C, 4 days) with the methanogenic reactor (35 degrees C, 16 days) and the results showed 84.8% and 11.4% higher methane yield and volatile solid reduction, respectively, compared with that of the single-stage anaerobic digestion system with HRT of 20 days at 35 degrees C. Moreover, different microbial morphologies were observed in the acidogenic- and methanogenic-phase reactors, which resulted from the temperature control and HRT adjustment. All the above results indicated that 45 degrees C was the optimum temperature to inhibit the activity of methanogenic bacteria in the acidogenic phase, and temperature staging and phase separation was thus accomplished. The advantages of the TSBP process were also confirmed by a full-scale waste-activated sludge anaerobic digestion project which was an energy self-sufficient system. PMID:24494492

  15. Composting of bio-waste, aerobic and anaerobic sludges--effect of feedstock on the process and quality of compost.

    PubMed

    Himanen, Marina; Hänninen, Kari

    2011-02-01

    In-vessel composting of three stocks with originally different degree of organic matter degradation was conducted for: (1) kitchen source-separated bio-waste (BW), (2) aerobic (AS) as well as (3) anaerobic sludges (AnS) from municipal wastewater treatment plant. Composting experiment lasted over a year. The highest activity of the process was in the BW compost. It was implied by the highest temperature, CO(2) release, ammonification and nitrification, intensive accumulation and removal of low-weight carboxylic acids (water- and NaOH-extractable). Between the sludges higher mineralization and CO2 release was in AnS, while ammonification and nitrification were higher in AS compost; no significant difference between sludge composts was noticed for dynamics of pH, conductivity, concentrations of LWCA, and some nutrient compounds and heavy metals. Nitrogen content of the final compost increased in BW, but decreased in AS and AnS. Phytotoxicity of Lepidium sativum was eliminated faster in sludge composts compared to BW compost. PMID:21095117

  16. Nitrification and CO2 fixation in hot springs in the presence and absence of a nitrification inhibitor

    NASA Astrophysics Data System (ADS)

    Hungate, B. A.; Dijkstra, P.; Brown, J.; Mau, R. L.; Thomas, S.; Dodsworth, J. A.; Hedlund, B. P.; Boyd, E. S.; de la Torre, J. R.; Jewell, T.

    2012-12-01

    Ammonium oxidation occurs in terrestrial and aquatic ecosystems, and from temperatures approaching freezing to close to 80 °C. This reaction is catalyzed by ammonium oxidase associated with both Bacteria and Archaea, although those associated with Archaea appear dominant at temperatures above ~ 60°C. For bacteria, this process is coupled to active CO2 uptake, although whether Archaea use this reaction in situ to drive C fixation has yet to be definitively established. For some hot spring communities, the Thaumarcheota (specifically close relatives of Nitrosocaldus yellowstonii) represent a substantial proportion of the microbial community. We conducted gross nitrification and CO2 fixation measurements to determine 1- the upper in situ temperature limit for nitrification and 2- the contribution of ammonium oxidizers to the community C fixation by inhibiting nitrification using allylthiourea (ATU). We used 15NO3- pool dilution to determine nitrification in sediment slurries and incubated sediment with 14C-labeled bicarbonate to measure C fixation. Sediment samples were collected from the Great Boiling Spring near Gerlach, Nevada. The water temperature ranged between 83 and 50°C depending on the location in the main pool. We collected samples at 82, 72, 59, and 51 °C. The sediment was homogenized, 15NO3- was added. The nitrification inhibitor ATU was added before adding the 15N label. One sample was immediately stored cold, while another was incubated overnight at the collection temperature. In parallel experiments, 14C bicarbonate was added to the headspace and likewise incubated in situ for several hours in the presence and absence of ATU. We observed significant nitrification at temperatures from 51-72 °C, but not at 82 °C. This nitrification was blocked by ATU. We also observed significant CO2 fixation at 51 and 59 °C, but not at higher temperature. CO2 fixation was not blocked by the nitrification inhibitor. We conclude that 1- ammonium oxidizers are

  17. Rapid detection of Nocardia amarae in the activated sludge process using enzyme-linked immunosorbent assay (ELISA).

    PubMed

    Iwahori, K; Miyata, N; Morisada, S; Suzuki, N

    2000-01-01

    Nocardia amarae, a mycolic acid-containing bacterium, has often been reported to cause foaming of activated sludge in wastewater treatment plants. In this study, the number of N. amarae cells in the activated sludge process was estimated by enzyme-linked immunosorbent assay (ELISA) with anti-N. amarae polyclonal antibody. Use of the antibody enabled N. amarae to be detected at levels of 10(4) to 10(7) colony forming units. On the other hand, the antibody reacted with only a small portion of activated sludge, in which no N. amarae cells were detected by the plate count method. Competitive ELISA was employed to estimate the N. amarae cells in samples taken from a municipal wastewater treatment plant, including raw wastewater and activated sludge foam. The cell numbers estimated by competitive ELISA corresponded well with those obtained by plate counts. Hence, the antibody produced in this study was shown to be effective for the rapid monitoring of N. amarae in the activated sludge process. PMID:16232779

  18. Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system.

    PubMed

    Kheradmand, S; Karimi-Jashni, A; Sartaj, M

    2010-06-01

    The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during 8 months experiment (COD concentrations of 48,552-62,150 mg/L). It was found that the system could reduce the COD of the leachate by 94% at a loading rate of 2.25g COD/L/d and 93% at loading rate of 3.37g COD/L/d. The anaerobic digester treatment was quite effective in removing Fe, Cu, Mn, and Ni. However, in the case of Zn, removal efficiency was about 50%. For the rest of the HMs the removal efficiencies were in the range 88.8-99.9%. Ammonia reduction did not occur in anaerobic digesters. Anaerobic reactors increased alkalinity about 3.2-4.8% in the 1st digester and 1.8-7.9% in the 2nd digester. In activated sludge unit, alkalinity and ammonia removal efficiency were 49-60% and 48.6-64.7%, respectively. Methane production rate was in the range of 0.02-0.04, 0.04-0.07, and 0.02-0.04 L/g COD(rem) for the 1st digester, the 2nd digester, and combination of both digesters, respectively; the methane content of the biogas varied between 60% and 63%. PMID:20194009

  19. Sorption of biodegradation end products of nonylphenol polyethoxylates onto activated sludge.

    PubMed

    Hung, Nguyen Viet; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori; Tsunoi, Shinji; Tanaka, Minoru

    2004-01-01

    Nonylphenol(NP), nonylphenoxy acetic acid (NP1EC), nonylphenol monoethoxy acetic acid (NP2EC), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) are biodegradation end products (BEPs) of nonionic surfactant nonylphenolpolyethoxylates (NPnEO). In this research, sorption of these compounds onto model activated sludge was characterized. Sorption equilibrium experiments showed that NP, NP1EO and NP2EO reached equilibrium in about 12 h, while equilibrium of NP1EC and NP2EC were reached earlier, in about 4 h. In sorption isotherm experiments, obtained equilibrium data at 28 degrees C fitted well to Freundlich sorption model for all investigated compounds. For NP1EC, in addition to Freundlich, equilibrium data also fitted well to Langmuir model. Linear sorption model was also tried, and equilibrium data of all NP, NP1EO, NP2EO and NP2EC except NP1EC fitted well to this model. Calculated Freundlich coefficient (K(F)) and linear sorption coefficient (K(D)) showed that sorption capacity of the investigated compounds were in order NP > NP2EO > NP1EO > NP1EC approximately NP2EC. For NP, NP1EO and NP2EO, high values of calculated K(F) and K(D) indicated an easy uptake of these compounds from aqueous phase onto activated sludge. Whereas, NP1EC and NP2EC with low values of K(F) and K(D) absorbed weakly to activated sludge and tended to preferably remain in aqueous phase. PMID:15495957

  20. Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system

    SciTech Connect

    Kheradmand, S.; Karimi-Jashni, A.; Sartaj, M.

    2010-06-15

    The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during 8 months experiment (COD concentrations of 48,552-62,150 mg/L). It was found that the system could reduce the COD of the leachate by 94% at a loading rate of 2.25 g COD/L/d and 93% at loading rate of 3.37 g COD/L/d. The anaerobic digester treatment was quite effective in removing Fe, Cu, Mn, and Ni. However, in the case of Zn, removal efficiency was about 50%. For the rest of the HMs the removal efficiencies were in the range 88.8-99.9%. Ammonia reduction did not occur in anaerobic digesters. Anaerobic reactors increased alkalinity about 3.2-4.8% in the 1st digester and 1.8-7.9% in the 2nd digester. In activated sludge unit, alkalinity and ammonia removal efficiency were 49-60% and 48.6-64.7%, respectively. Methane production rate was in the range of 0.02-0.04, 0.04-0.07, and 0.02-0.04 L/g COD{sub rem} for the 1st digester, the 2nd digester, and combination of both digesters, respectively; the methane content of the biogas varied between 60% and 63%.

  1. Determination of detoxification to Daphnia magna of four pharmaceuticals and seven surfactants by activated sludge.

    PubMed

    Dave, Göran; Herger, Gabriella

    2012-07-01

    Pharmaceuticals are bioactive compounds generally resistant to biodegradation, which can make them problematic when they are released into nature. The use pattern for pharmaceuticals means that they are discharged into water via sewage treatment plants. Also surfactants are discharged through sewage treatment plants, primarily due to their use in detergents and shampoos and other cleaners. In this study the acute toxicity to Daphnia magna of four pharmaceuticals (ciprofloxacin, ibuprofen, paracetamol and zinc pyrithione) and seven surfactants (C8 alkyl glucoside, C6 alkyl glucoside, sodium caprylimidiopropionate, tallow-trimethyl-ammonium chloride, potassium decylphosphate, propylheptanol ethoxylate and alkylmonoethanolamide ethoxylate) was determined. Abiotic (without activated sludge bacteria) and biotic (with activated sludge bacteria) detoxification was also determined. The 24-h EC50s ranged from 2 μg L(-1) for the most toxic substance (zinc pyrithione) to 2 g L(-1) for the least toxic compound (C6 alkyl glucoside). Detoxification rates determined as the ratio between initial EC50 and EC50 after 1 week in water with activated sludge bacteria ranged from 0.4 (paracetamol) to 13 (zinc pyrithione). For most of these chemicals detoxification rate decreased after 1 week, but for one (alkylmonoethanolamide ethoxylate) it increased from about 2 to 30 times after 2 weeks. Many of these chemicals were "detoxified" also abiotically at about the same rate as biotically. Further studies are needed to determine the degradation products that were precipitated (aggregated) for some of the tested chemicals. Altogether, this study has shown that there are large differences in toxicity among chemicals entering sewage treatment plants, but also that the detoxification of them can differ. Therefore, the detoxification should receive more attention in the hazard and risk assessment of chemicals entering sewage treatment plants. PMID:22480943

  2. Long-term effects of antibiotics on the elimination of chemical oxygen demand, nitrification, and viable bacteria in laboratory-scale wastewater treatment plants.

    PubMed

    Schmidt, Susan; Winter, Josef; Gallert, Claudia

    2012-10-01

    Antibiotics and other pharmaceuticals are contaminants of the environment because of their widespread use and incomplete removal by microorganisms during wastewater treatment. The influence of a mixture of ciprofloxacin (CIP), gentamicin (GM), sulfamethoxazole (SMZ)/trimethoprim (TMP), and vancomycin (VA), up to a final concentration of 40 mg/L, on the elimination of chemical oxygen demand (COD), nitrification, and survival of bacteria, as well as the elimination of the antibiotics, was assessed in a long-term study in laboratory treatment plants (LTPs). In the presence of 30 mg/L antibiotics, nitrification of artificial sewage by activated sludge ended at nitrite. Nitrate formation was almost completely inhibited. No nitrification at all was possible in the presence of 40 mg/L antibiotics. The nitrifiers were more sensitive to antibiotics than heterotrophic bacteria. COD elimination in antibiotic-stressed LTPs was not influenced by ≤20 mg/L antibiotics. Addition of 30 mg/L antibiotic mixture decreased COD removal efficiency for a period, but the LTPs recovered. Similar results were obtained with 40 mg/L antibiotic mixture. The total viable count of bacteria was not affected negatively by the antibiotics. It ranged from 2.2 × 10(6) to 8.2 × 10(6) colony-forming units per milliliter (CFU/mL) compared with the control at 1.4 × 10(6)-6.3 × 10(6) CFU/mL. Elimination of the four antibiotics during phases of 2.4-30 mg/L from the liquid was high for GM (70-90 %), much lower for VA, TMP, and CIP (0-50 %), and highly fluctuating for SMZ (0-95 %). The antibiotics were mainly adsorbed to the sludge and not biodegraded. PMID:22622431

  3. Characterization of the In Situ Ecophysiology of Novel Phylotypes in Nutrient Removal Activated Sludge Treatment Plants

    PubMed Central

    McIlroy, Simon Jon; Awata, Takanori; Nierychlo, Marta; Albertsen, Mads; Kindaichi, Tomonori; Nielsen, Per Halkjær

    2015-01-01

    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 for the majority. This study applied microautoradiography coupled with fluorescence in situ hybridization (MAR-FISH) for the in situ characterization of selected genus-level-phylotypes for which limited physiological information is available. These included Sulfuritalea and A21b, both within the class Betaproteobacteria, as well as Kaga01, within sub-group 10 of the phylum Acidobacteria. While the Sulfuritalea spp. were observed to be metabolically versatile, the A21b and Kaga01 phylotypes appeared to be highly specialized. PMID:26340564

  4. Effect of humic acids with different characteristics on fermentative short-chain fatty acids production from waste activated sludge.

    PubMed

    Liu, Kun; Chen, Yinguang; Xiao, Naidong; Zheng, Xiong; Li, Mu

    2015-04-21

    Recently, the use of waste activated sludge to bioproduce short-chain fatty acids (SCFA) has attracted much attention as the sludge-derived SCFA can be used as a preferred carbon source to drive biological nutrient removal or biopolymer (polyhydroxyalkanoates) synthesis. Although large number of humic acid (HA) has been reported in sludge, the influence of HA on SCFA production has never been documented. This study investigated the effects on sludge-derived SCFA production of two commercially available humic acids (referred to as SHHA and SAHA purchased respectively from Shanghai Reagent Company and Sigma-Aldrich) that differ in chemical structure, hydrophobicity, surfactant properties, and degree of aromaticity. It was found that SHHA remarkably enhanced SCFA production (1.7-3.5 folds), while SAHA had no obvious effect. Mechanisms study revealed that all four steps (solubilization, hydrolysis, acidification, and methanogenesis) involved in sludge fermentation were unaffected by SAHA. However, SHHA remarkably improved the solubilization of sludge protein and carbohydrate and the activity of hydrolysis enzymes (protease and α-glucosidase) owing to its greater hydrophobicity and protection of enzyme activity. SHHA also enhanced the acidification step by accelerating the bioreactions of glyceradehyde-3P → d-glycerate 1,3-diphosphate, and pyruvate → acetyl-CoA due to its abundant quinone groups which served as electron acceptor. Further investigation showed that SHHA negatively influenced the activity of acetoclastic methanogens for its competition for electrons and inhibition on the reaction of acetyl-CoA → 5-methyl-THMPT, which caused less SCFA being consumed. All these observations were in correspondence with SHHA significantly enhancing the production of sludge derived SCFA. PMID:25825920

  5. Influence of activated carbon and biochar on phytotoxicity of air-dried sewage sludges to Lepidium sativum.

    PubMed

    Oleszczuk, Patryk; Rycaj, Marcin; Lehmann, Johannes; Cornelissen, Gerard

    2012-06-01

    The goal of the research was to determine the phytotoxicity (using Lepidium sativum) of two activated carbon/biochar-amended sewage sludges. Apart from the impact of the AC/biochar dose, the influence of biochar particle diameter (<300, 300-500 and >500 μm) and the influence of the contact time (7, 60, 90 days) between AC/biochar and sewage sludges on their phytotoxicity was also assessed. No negative impact of sewage sludges on seed germination was observed (P>0.05). The application of AC or biochar to the sludges positively affected root growth by reducing the harmful effect by 7.8 to 42% depending on the material used. Furthermore, the reduction range clearly depended on the type of sewage sludge. No differences were observed in the inhibition of the toxic effect between both biochar types used and the biochar particle size. The extension of the contact time between AC/biochar and sewage sludges had a negative impact on root growth. PMID:22516757

  6. Anaerobic treatment of activated sludge from Swedish pulp and paper mills--biogas production potential and limitations.

    PubMed

    Karlsson, Anna; Truong, Xu-Bin; Gustavsson, Jenny; Svensson, Bo H; Nilsson, Fredrik; Ejlertsson, Jörgen

    2011-10-01

    The methane potential of activated sludge from six Swedish pulp and paper mills was evaluated. The methane production potential of sludge samples ranged from 100-200 NmL CH4 g(-1) volatile solids (VS) and for four of the six sludge samples the potential exceeded 170 NmL CH4 g(-1) VS. The effects of sludge age and dewatering on the methane production potential were evaluated. The effects of enzymatic and ultrasonic pre-treatment on the digestibility of sludge were also investigated, but energy or enzyme inputs in viable ranges did not exert a detectable, positive effect. Long-term, semi-continuous trials with sludge from two of the mills were also conducted in attempts to develop stable biogas production at loading rates up to 4 g VS L(-1). Cobalt addition (0.5 mg L(-1)) was here found to positively affect the turnover of acetate. High viscosity was a problem in all the experimental reactors and this limited the organic loading rate. PMID:22329147

  7. A laboratory batch reactor test for assessing nonspeciated volatile organic compound biodegradation in activated sludge.

    PubMed

    Cano, M L; Saterbak, A; van Compernolle, R; Williams, M P; Huot, M E; Rhodes, I A; Allen, C C

    2003-01-01

    The relative rates of biodegradation and stripping and volatilization of nonspeciated volatile organic compounds (VOCs) in wastewater treated with aerobic activated-sludge processes can be quantified using a newly developed procedure. This method was adapted from the original aerated draft tube reactor test that was developed to measure biodegradation rate constants for specific volatile pollutants of interest. The original batch test has been modified to include solid-phase microextraction (SPME) fibers for sampling in the gas phase. The experimental procedure using SPME fibers does not require specific identification and quantitation of individual pollutants and can be used to evaluate wastewater with multiple VOCs. To illustrate use of this procedure, laboratory experiments were conducted using biomass and wastewater or effluent from three activated-sludge treatment systems. Each experiment consisted of two trials: a stripping-only trial without biomass and a stripping plus biodegradation trial using biomass from the activated-sludge unit of interest. Data from the two trials were used to quantify the rates of biodegradation by difference. The activated-sludge systems tested were a laboratory diffused-air reactor treating refinery wastewater, a full-scale surface aerated reactor treating a petrochemical wastewater, and a full-scale diffused-air reactor treating a variety of industrial effluents. The biodegradation rate constant data from each laboratory batch experiment were used in model calculations to quantify the fraction emitted (fe) and the fraction biodegraded (fbio) for each system. The fe values ranged from a maximum of 0.01 to a maximum of 0.32, whereas fbio values ranged from a minimum of 0.40 to a minimum 0.95. Two of these systems had been previously tested using a more complicated experimental approach, and the current results were in good agreement with previous results. These results indicate that biodegradation rate constant data from this

  8. Biodegradation of didecyldimethylammonium chloride by Pseudomonas fluorescens TN4 isolated from activated sludge.

    PubMed

    Nishihara, T; Okamoto, T; Nishiyama, N

    2000-04-01

    Bacteria that degrade didecyldimethylammonium chloride (DDAC) were isolated from activated sludge from a municipal sewage treatment plant by enrichment culture with DDAC as a sole carbon source. One of the isolates, Pseudomonas fluorescens TN4, degraded DDAC to produce decyldimethylamine and subsequently, dimethylamine, as the intermediates. The TN4 strain also assimilated the other quaternary ammonium compounds (QACs), alkyltrimethyl- and alkylbenzyldimethyl-ammonium salts, but not alkylpyridinium salts. TN4 was highly resistant to these QACs and degraded them by an N-dealkylation process. These data mean that there are some QAC-resistant and QAC-degrading bacteria such as TN4 in the environment. PMID:10792522

  9. 6:2 fluorotelomer sulfonate aerobic biotransformation in activated sludge of waste water treatment plants.

    PubMed

    Wang, Ning; Liu, Jinxia; Buck, Robert C; Korzeniowski, Stephen H; Wolstenholme, Barry W; Folsom, Patrick W; Sulecki, Lisa M

    2011-02-01

    The aerobic biotransformation of 6:2 FTS salt [F(CF2)6CH2CH2SO3- K+] was determined in closed bottles for 90d in diluted activated sludge from three waste water treatment plants (WWTPs) to compare its biotransformation potential with that of 6:2 FTOH [F(CF2)6CH2CH2OH]. The 6:2 FTS biotransformation was relatively slow, with 63.7% remaining at day 90 and all observed transformation products together accounting for 6.3% of the initial 6:2 FTS applied. The overall mass balance (6:2 FTS plus observed transformation products) at day 90 in live and sterile treatments averaged 70% and 94%, respectively. At day 90, the stable transformation products observed were 5:3 acid [F(CF2)5CH2CH2COOH, 0.12%], PFBA [F(CF2)3COOH, 0.14%], PFPeA [F(CF2)4COOH, 1.5%], and PFHxA [F(CF2)5COOH 1.1%]. In addition, 5:2 ketone [F(CF2)5C(O)CH3] and 5:2 sFTOH [F(CF2)5CH(OH)CH3] together accounted for 3.4% at day 90. The yield of all the stable transformation products noted above (2.9%) was 19 times lower than that of 6:2 FTOH in aerobic soil. Thus 6:2 FTS is not likely to be a major source of PFCAs and polyfluorinated acids in WWTPs. 6:2 FTOH, 6:2 FTA [F(CF2)6CH2COOH], and PFHpA [F(CF2)6COOH] were not observed during the 90-d incubation. 6:2 FTS primary biotransformation bypassed 6:2 FTOH to form 6:2 FTUA [F(CF2)5CF=CHCOOH], which was subsequently degraded via pathways similar to 6:2 FTOH biotransformation. A substantial fraction of initially dosed 6:2 FTS (24%) may be irreversibly bound to diluted activated sludge catalyzed by microbial enzymes. The relatively slow 6:2 FTS degradation in activated sludge may be due to microbial aerobic de-sulfonation of 6:2 FTS, required for 6:2 FTS further biotransformation, being a rate-limiting step in microorganisms of activated sludge in WWTPs. PMID:21112609

  10. Degradation of the unbiodegradable particulate fraction (XU) from different activated sludges during batch digestion tests at ambient temperature.

    PubMed

    Habermacher, Jonathan; Benetti, Antonio Domingues; Derlon, Nicolas; Morgenroth, Eberhard

    2016-07-01

    One strategy for the management of excess sludge in small wastewater treatment plants (WWTPs) consists in minimizing the excess sludge production by operating the WWTP at very long solids retention times (SRTs > 30 days). A number of recent studies have suggested that sludge minimization at very long SRT results from the degradation of the unbiodegradable particulate fraction (XU) (influent unbiodegradable compounds and endogenous decay products). But the biodegradability of the unbiodegradable particulate fraction has only been evaluated during batch digestion test performed at ambient temperature with sludge fed with synthetic wastewaters. It is not clear to what extent observations made for sludge fed with synthetic influents can be transposed to sludge fed with real influent. The current study thus focused on evaluating the biodegradability of the unbiodegradable particulate fraction for sludge fed with real wastewater. Batch digestion tests (400 days, ambient temperature) were conducted with three different sludges fed with either synthetic or real influents and exposed to aerobic or intermittent aeration conditions. Our results indicate that volatile suspended solids (VSS) decreased even after complete decay of the active biomass (i.e., after 30 days of aerobic batch digestion) indicating that the unbiodegradable particulate fraction is biodegradable. However, very low degradation rates of the unbiodegradable particulate fraction were monitored after day 30 of digestion (0.7-1.7·10(-3) d(-1)). These values were in the lower range of previously published values for synthetic wastewaters (1-7.5·10(-3) d(-1)). The low values determined in our study indicate that the rate could decrease over time or that sludge composition influences the degradability of the unbiodegradable particulate fraction. But our results also demonstrate that extracellular polymeric substances (EPS) have a minor impact on the biodegradability of the unbiodegradable particulate

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

    PubMed

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

    2016-09-01

    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. PMID:26905629

  12. Diagnostic investigation of steroid estrogen removal by activated sludge at varying solids retention time.

    PubMed

    Petrie, Bruce; McAdam, Ewan J; Hassard, Francis; Stephenson, Tom; Lester, John N; Cartmell, Elise

    2014-10-01

    The impact of solids retention time (SRT) on estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2) removal in an activated sludge plant (ASP) was examined using a pilot plant to closely control operation. Exsitu analytical methods were simultaneously used to enable discrimination of the dominant mechanisms governing estrogen removal following transitions in SRT from short (3d) to medium (10d) and long (27d) SRTs which broadly represent those encountered at full-scale. Total estrogen (∑EST, i.e., sum of E1, E2, E3 and EE2) removals which account for aqueous and particulate concentrations were 70±8, 95±1 and 93±2% at 3, 10 and 27d SRTs respectively. The improved removal observed following an SRT increase from 3 to 10d was attributable to the augmented biodegradation of the natural estrogens E1 and E2. Interestingly, estrogen biodegradation per bacterial cell increased with SRT. These were 499, 1361 and 1750ng 10(12) viable cells(-1)d(-1). This indicated an improved efficiency of the same group or the development of a more responsive group of bacteria. In this study no improvement in absolute ∑EST removal was observed in the ASP when SRT increased from 10 to 27d. However, batch studies identified an augmented biomass sorption capacity for the more hydrophobic estrogens E2 and EE2 at 27d, equivalent to an order of magnitude. The lack of influence on estrogen removal during pilot plant operation can be ascribed to their distribution within activated sludge being under equilibrium. Consequently, lower wastage of excess sludge inherent of long SRT operation counteracts any improvement in sorption. PMID:25065796

  13. Identification of selected microorganisms from activated sludge capable of benzothiazole and benzotriazole transformation.

    PubMed

    Kowalska, Katarzyna; Felis, Ewa

    2015-01-01

    Benzothiazole (BT) and benzotriazole (BTA) are present in the environment - especially in urban and industrial areas, usually as anthropogenic micropollutants. BT and BTA have been found in the municipal and industrial wastewater, rivers, soil, groundwater, sediments and sludge. The origins of those substances' presence in the environment are various industry branches (food, chemical, metallurgical, electrical), households and surface runoff from industrial areas. Increasingly strict regulations on water quality and the fact that the discussed compounds are poorly biodegradable, make them a serious problem in the environment. Considering this, it is important to look for environmentally friendly and socially acceptable ways to remove BT and BTA. The aim of this study was to identify microorganisms capable of BT and BTA transformation or/and degradation in aquatic environment. Selected microorganisms were isolated from activated sludge. The identification of microorganisms capable of BT and BTA removal was possible using molecular biology techniques (PCR, DNA sequencing). Among isolated microorganisms of activated sludge are bacteria potentially capable of BT and BTA biotransformation and/or removal. The most common bacteria capable of BT and BTA transformation were Rhodococcus sp., Enterobacter sp., Arthrobacter sp. They can grow in a medium with BT and BTA as the only carbon source. Microorganisms previously adapted to the presence of the studied substances at a concentration of 10 mg/l, showed a greater rate of growth of colonies on media than microorganisms unconditioned to the presence of such compounds. Results of the biodegradation test suggest that BT was degraded to a greater extent than BTA, 98-100% and 11-19%, respectively. PMID:26641641

  14. Enhanced digestion of waste activated sludge using microbial electrolysis cells at ambient temperature.

    PubMed

    Asztalos, Joseph R; Kim, Younggy

    2015-12-15

    This study examined the effects of the microbial electrolysis cell (MEC) reactions on anaerobic digestion of waste activated sludge from municipal wastewater treatment under ambient temperature conditions (22-23 °C). Two lab-scale digesters, a control anaerobic digester and an electrically-assisted digester (EAD - equipped with a MEC bioanode and cathode) were operated under three solids retention times (SRT = 7, 10 and 14 days) at 22.5 ± 0.5 °C. A numerical model was also built by including the MEC electrode reactions in Anaerobic Digestion Model No.1. In experiments, the EAD showed reduced concentration of acetic acid, propionic acid, n-butyric acid and iso-butyric acid. This improved performance of the EAD is thought to be achieved by direct oxidation of the short-chain fatty acids at the bioanode as well as indirect contribution of low acetic acid concentration to enhancing beta-oxidation. The VSS and COD removal was consistently higher in the EAD by 5-10% compared to the control digester for all SRT conditions at 22.5 ± 0.5 °C. When compared to mathematical model results, this additional COD removal in the EAD was equivalent to that which would be achieved with conventional digesters at mesophilic temperatures. The magnitude of electric current in the EAD was governed by the organic loading rate while conductivity and acetic acid concentration showed negligible effects on current generation. Very high methane content (∼95%) in the biogas from both the EAD and control digester implies that the waste activated sludge contained large amounts of lipids and other complex polymeric substances compared to primary sludge. PMID:26051356

  15. Ecotoxicity and Biodegradability Assessment of Metalworking Fluids by Activated Sludge Bacteria

    NASA Astrophysics Data System (ADS)

    Gerulová, Kristína; Mihálková, Adriána; Šergovičová, Magdaléna; Guoth, Alexander; Nádašská, Zuzana

    2011-01-01

    The main aim of this study was to evaluate toxicity of metalworking fluids to bacterial consortium of activated sludge according to OECD 209 (STN EN ISO 8192) and a potential of the same sludge to degrade a part of the fluids according to OECD 302B. Toxic impact can affect different responses, particularly the inhibition of respiration measured from the oxygen consumption in a closed bottle. The degradation rate was calculated from COD according to the authors such as van der Gast and Ian Thompson (1, 2) who tested the degradability of some MWFs in bioreactors by measuring the COD. The lowest toxic MWF's were Cimstar 597 and Emulzin H (the highest tested concentration was below EC50), then Zubora TXS (EC50 - 11 349 mg l-1), Aquamet LAK-E (EC50 - 5 228 mg l-1), Adrana D 407 (EC50 - 4 351 mg l-1) followed, and finally, Hocut 3380 (EC50 - 2 339 mg l-1) was assessed as the most toxic. Important in this test (OECD 302B) is that the starting concentration of the tested substance must not decrease below 20% after 3 hours of cultivating. After that, it is impossible to distinguish biological degradation of organic matter from abiotic elimination from the suspension through adsorption. Tested were 8 MWFs of similar concentration and different addition of activated sludge - 0.25 g l-1, 0.50 g l-1 and 1.00 g l-1. The test showed that, after the first 3 hours of cultivating, adsorption grew with the increasing amount of inoculums, except of Akvol B (the decrease of the starting concentration after the first 3 hours of cultivating was the lowest of all and below 20%). It can be stated that, according to the test basic conditions, all the tested MWFs have a potential to ultimate degradation.

  16. Substrate uptake tests and quantitative FISH show differences in kinetic growth of bulking and non-bulking activated sludge.

    PubMed

    Lou, Inchio; de Los Reyes, Francis L

    2005-12-20

    The competition between filaments and floc formers in activated sludge has been historically described using kinetic selection. However, recent studies have suggested that bacterial storage may also be an important factor in microbial selection, since the dynamic nature of substrate flows into wastewater treatment plants elicit transient responses from microorganisms. Respirometry-based kinetic selection should thus be reevaluated by considering cell storage, and a more reliable method should be developed to include bacterial storage in the analysis of growth of filaments and floc formers in activated sludge. In this study, we applied substrate uptake tests combined with metabolic modeling to determine the growth rates, yields and maintenance coefficients of bulking and non-bulking activated sludge developed in lab scale reactors under feast and famine conditions. The results of quantitative fluorescence in situ hybridization (FISH) showed that the filaments Eikelboom Type 1851, Type 021N, and Thiothrix nivea were dominant in bulking sludge, comprising 42.0 % of mixed liquor volatile suspended solids (MLVSS), with 61.6% of the total filament length extending from flocs into bulk solution. Only low levels of Type 1851 filament length (4.9% of MLVSS) occurred in non-bulking sludge, 83.0% of which grew inside the flocs. The kinetic parameters determined from the substrate uptake tests were consistent with those from respirometry and showed that filamentous bulking sludge had lower growth rates and maintenance coefficients than non-bulking sludge. These results provide support for growth kinetic differences in explaining the competitive strategy of filamentous bacteria. PMID:16155949

  17. Ammonium-oxidizing bacteria facilitate aerobic degradation of sulfanilic acid in activated sludge.

    PubMed

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

    2014-01-01

    Sulfanilic acid (SA) is a toxic sulfonated aromatic amine commonly found in anaerobically treated azo dye contaminated effluents. Aerobic acclimatization of SA-degrading mixed microbial culture could lead to co-enrichment of ammonium-oxidizing bacteria (AOB) because of the concomitant release of ammonium from SA oxidation. To what extent the co-enriched AOB would affect SA oxidation at various ammonium concentrations was unclear. Here, a series of batch kinetic experiments were conducted to evaluate the effect of AOB on aerobic SA degradation in an acclimatized activated sludge culture capable of oxidizing SA and ammonium simultaneously. To account for the effect of AOB on SA degradation, allylthiourea was used to inhibit AOB activity in the culture. The results indicated that specific SA degradation rate of the mixed culture was negatively correlated with the initial ammonium concentration (0-93 mM, R²= 0.99). The presence of AOB accelerated SA degradation by reducing the inhibitory effect of ammonium (≥ 10 mM). The Haldane substrate inhibition model was used to correlate substrate concentration (SA and ammonium) and oxygen uptake rate. This study revealed, for the first time, that AOB could facilitate SA degradation at high concentration of ammonium (≥ 10 mM) in an enriched activated sludge culture. PMID:25259503

  18. Impact of activated sludge process configuration on removal of micropollutants and estrogenicity.

    PubMed

    Ogunlaja, O O; Parker, W J

    2015-01-01

    The efficacy of three different wastewater treatment configurations, conventional activated sludge (CAS), nitrifying activated sludge (NAS) and biological nutrient removal (BNR) for removal of selected micropollutants from authentic wastewater was investigated. The processes were also characterized based on their proficiency to reduce the estrogenic activity of the influent wastewater using the in vitro recombinant yeast assay. The removal efficiency of trimethoprim improved with the complexity of the three treatment process configurations. Ibuprofen, androstendione, sulfamethoxazole, nonyl-phenol, estrone and bisphenol-A had moderate to high removals (>65%) while carbamazepine and meprobamate remained recalcitrant in the three treatment process configurations. The removal of gemfibrozil was better in the NAS than in BNR and CAS treatment configurations. The yeast estrogen screen (YES) assay analyses showed an improvement in estrogenicity removal in the BNR and NAS treatment configurations as compared to the CAS treatment configuration. Comparing the estrogenic responses from the three treatment configurations, the removal efficiencies followed the order of BNR=NAS>CAS and all were greater than 81%. PMID:26177411

  19. Ammonia-oxidizing microbial communities in reactors with efficient nitrification at low-dissolved oxygen

    PubMed Central

    Fitzgerald, Colin M.; Camejo, Pamela; Oshlag, J. Zachary; Noguera, Daniel R.

    2015-01-01

    Ammonia-oxidizing microbial communities involved in ammonia oxidation under low dissolved oxygen (DO) conditions (<0.3 mg/L) were investigated using chemostat reactors. One lab-scale reactor (NS_LowDO) was seeded with sludge from a full-scale wastewater treatment plant (WWTP) not adapted to low-DO nitrification, while a second reactor (JP_LowDO) was seeded with sludge from a full-scale WWTP already achieving low-DO nitrifiaction. The experimental evidence from quantitative PCR, rDNA tag pyrosequencing, and fluorescence in situ hybridization (FISH) suggested that ammonia-oxidizing bacteria (AOB) in the Nitrosomonas genus were responsible for low-DO nitrification in the NS_LowDO reactor, whereas in the JP_LowDO reactor nitrification was not associated with any known ammonia-oxidizing prokaryote. Neither reactor had a significant population of ammonia-oxidizing archaea (AOA) or anaerobic ammonium oxidation (anammox) organisms. Organisms isolated from JP_LowDO were capable of autotrophic and heterotrophic ammonia utilization, albeit without stoichiometric accumulation of nitrite or nitrate. Based on the experimental evidence we propose that Pseudomonas, Xanthomonadaceae, Rhodococcus, and Sphingomonas are involved in nitrification under low-DO conditions. PMID:25506762

  20. Activated sludge

    SciTech Connect

    1987-12-31

    This manual is designed to give the operator a framework for decision-making based on an understanding of the biological and chemical principles at work and the past experiencing of the more than 60 individuals who contributed to this manual. Chapters cover: process and equipment descriptions, process control, energy conservation, and trouble-shooting. The manual is intended to be used as both a training tool and a reference book. The easy-to-follow format will make the book useful to the newcomer as well as to the experienced operator.

  1. In situ identification of nocardioform actinomycetes in activated sludge using fluorescent rRNA-targeted oligonucleotide probes.

    PubMed

    Schuppler, M; Wagner, M; Schön, G; Göbel, U B

    1998-01-01

    Hitherto, few environmental samples have been investigated by a 'full cycle rRNA analysis'. Here the results of in situ hybridization experiments with specific rRNA-targeted oligonucleotide probes developed on the basis of new sequences derived from a previously described comparative 16S rRNA analysis of nocardioform actinomycetes in activated sludge are reported. Application of the specific probes enabled identification and discrimination of the distinct populations of nocardioform actinomycetes in activated sludge. One of the specific probes (DLP) detected rod-shaped bacteria which were found in 13 of the 16 investigated sludge samples from various wastewater treatment plants, suggesting their importance in the wastewater treatment process. Another probe (GLP2) hybridized with typically branched filaments of nocardioforms mainly found in samples from enhanced biological phosphorus removal plants, suggesting that these bacteria are involved in sludge foaming. The combination of in situ hybridization with fluorescently labelled rRNA-targeted oligonucleotide probes and confocal laser scanning microscopy improved the detection of nocardioform actinomycetes, which often showed only weak signals inside the activated-sludge flocs. PMID:9467916

  2. Sludge reduction at low ozone doses: predictive effects and full-scale study.

    PubMed

    Romero, P; Coello, M D; Aragón, C A; Eusebi, A L

    2015-01-01

    The activated sludge process is the most widely used wastewater treatment. The main drawback of this technology is the excess sludge production (ESP). The ozonation of sludge of the recirculation line is used to reduce the ESP. In this study, ozonation was applied on a fraction of sludge of the recirculation line in a full-scale plant (50,000 population equivalent) at a lower-specific ozone dose (SOD) compared to previous studies. The results of batch tests to predict the main effect of the technology on the biomass activities are reported. Specifically, tests at 0.7-5 g O₃/kg MLVSS (mixed liquor volatile suspended solids) doses were made to evaluate the changes of the nitrification and denitrification rates, the population of phosphate-accumulating organisms and the gravitational properties. A certain reduction of the impact of ozonation on the kinetic parameters of sludge for values of SOD over 2 g O₃/kg MLVSS was found. The present study highlights also the use of the ratio of ozonated biomass to total biomass as an important operative parameter for ozonation in full-scale plants. Reduction in ESP in the wastewater treatment plant was equal to 10% as dry solids applying a SOD from 1.03 to 1.63 g O₃/kg MLVSS. An analysis of the economic cost of the technique is also reported. PMID:25633941

  3. Identification and quantification of microbial populations in activated sludge and anaerobic digestion processes.

    PubMed

    Reyes, M; Borrás, L; Seco, A; Ferrer, J

    2015-01-01

    Eight different phenotypes were studied in an activated sludge process (AeR) and anaerobic digester (AnD) in a full-scale wastewater treatment plant by means of fluorescent in situ hybridization (FISH) and automated FISH quantification software. The phenotypes were ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, denitrifying bacteria, phosphate-accumulating organisms (PAO), glycogen-accumulating organisms (GAO), sulphate-reducing bacteria (SRB), methanotrophic bacteria and methanogenic archaea. Some findings were unexpected: (a) Presence of PAO, GAO and denitrifiers in the AeR possibly due to unexpected environmental conditions caused by oxygen deficiencies or its ability to survive aerobically; (b) presence of SRB in the AeR due to high sulphate content of wastewater intake and possibly also due to digested sludge being recycled back into the primary clarifier; (c) presence of methanogenic archaea in the AeR, which can be explained by the recirculation of digested sludge and its ability to survive periods of high oxygen levels; (d) presence of denitrifying bacteria in the AnD which cannot be fully explained because the nitrate level in the AnD was not measured. However, other authors reported the existence of denitrifiers in environments where nitrate or oxygen was not present suggesting that denitrifiers can survive in nitrate-free anaerobic environments by carrying out low-level fermentation; (e) the results of this paper are relevant because of the focus on the identification of nearly all the significant bacterial and archaeal groups of microorganisms with a known phenotype involved in the biological wastewater treatment. PMID:25409582

  4. Start-up of the ananmmox process from the conventional activated sludge in a hybrid bioreactor.

    PubMed

    Duan, Xiumei; Zhou, Jiti; Qiao, Sen; Yin, Xin; Tian, Tian; Xu, Fangdi

    2012-01-01

    The anaerobic ammonium oxidation (anammox) process was successfully started up from conventional activated sludge using a hybrid bioreactor within 2 months. The average removal efficiencies of ammonia and nitrite were both over 80%, and the maximum total nitrogen removal rate of 1.85 kg N/(m3 x day) was obtained on day 362 with the initial sludge concentration of 0.7 g mixed liquor suspended solids (MLSS)/L. Scanning electron microscope (SEM) observation of the granular sludge in the hybrid reactor clearly showed a high degree of compactness and cell sphericity, and the cell size was quite uniform. Transmission electron microscope photos showed that cells were round or oval, the cellular diameter was 0.6-1.0 microm, and the percentage of the anammoxosome compartment was 51%-85% of the whole cell volume. Fluorescence in situ hybridization analysis (FISH) indicated that anammox bacteria became the dominant population in the community (accounting for more than 51% of total bacteria on day 250). Seven planctomycete 16S rRNA gene sequences were present in the 16S rRNA gene clone library generated from the biomass and affiliated to Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia sp., a new anammox species. In addition, the average effluent suspended solid (MLSS) concentrations of outlets I (above the non-woven carrier) and II (below the non-woven carrier) were 0.0009 and 0.0035 g/L, respectively. This showed that the non-woven carrier could catch the biomass effectively, which increased biomass and improved the nitrogen removal rate in the reactor. PMID:23505876

  5. Iron and phosphorus speciation in Fe-conditioned membrane bioreactor activated sludge.

    PubMed

    Wu, Hao; Ikeda-Ohno, Atsushi; Wang, Yuan; Waite, T David

    2015-06-01

    Iron dosing of membrane bioreactors (MBRs) is widely used as a means of meeting effluent phosphorus targets but there is limited understanding of the nature of iron and phosphorus-containing solids that are formed within the bioreactor (an important issue in view of the increasing interest in recovering phosphorus from wastewaters). Of particular challenge is the complexity of the MBR system and the variety of reactions that can occur on addition of iron salts to a membrane bioreactor. In this study, the performances of bench scale MBRs with dosing of either ferrous or ferric salts were monitored for a period of four months. The distributions of Fe and P-species in the Fe-conditioned sludges were determined using X-ray absorption spectroscopy (XAS) at the Fe K-edge and the P K-edge. Regardless of whether iron was dosed to the anoxic or aerobic chambers and regardless of whether ferrous (Fe(II)) or ferric (Fe(III)) iron was dosed, iron present in the minerals in the conditioned sludges was consistently in the +III oxidation state. Fitting of the Fe K-edge EXAFS spectra revealed that an Fe(III)-phosphate species was the main Fe species present in all cases with the remaining fraction dominated by lepidocrocite (γ-FeOOH) in the Fe(II)-dosed case and ferrihydrite (am-FeOOH) in the Fe(III)-dosed case. Approximately half the phosphorus in the activated sludge samples was present as a distinct Fe-PO4 mineral (such as strengite or an amorphous ferric hydroxyl phosphate analogue of strengite) and half as phosphorus adsorbed to an iron oxyhydroxide mineral phase indicating that both co-precipitation and adsorption of phosphorus by iron contribute to removal of phosphorus from the MBR supernatant. PMID:25900910

  6. Conditions for supplemental biogenic substrates to enhance activated sludge degradation of xenobiotic.

    PubMed

    Nguyen, Lan Huong; Chong, Nyuk-Min

    2015-10-01

    The effects of biogenic presence on the degradation of xenobiotic organics by natural microbial populations have been reported as either advantageous or disadvantageous. The inconsistency of the reports implies there could be a turning point from disadvantageous to advantageous outcomes so that conditions may exist that could bring an optimum advantage. This study tested the supplementations of varying concentrations of sucrose and peptone, separately and combined, to acclimated activated sludge degradation of xenobiotic 2,4-D, while other operational and microbiological conditions were held constant. Our test results showed that biogenic may indeed enhance or slow down xenobiotic degradation rates. The highest enhancements exist at concentrations of 50 and 80 mg/L, respectively, for sucrose and peptone when supplemented separately, and 20 mg/L sucrose and 40 mg/L peptone combined. Conditions for advantageous biogenic supplementation were identified for activated sludge degradation of a xenobiotic; specifically, the highest degradation rate enhancements occurred when biogenic supplementation was approximately 0.5 to 0.7 the concentration of 2,4-D base on chemical oxygen demand (COD), which brought a biomass yield of approximately double that yielded by 2,4-D. Kinetics analyses provided clues for the possible causes of advantageous and disadvantageous effects due to biogenic supplementation. PMID:26062533

  7. CFD-aided modelling of activated sludge systems - A critical review.

    PubMed

    Karpinska, Anna M; Bridgeman, John

    2016-01-01

    Nowadays, one of the major challenges in the wastewater sector is the successful design and reliable operation of treatment processes, which guarantee high treatment efficiencies to comply with effluent quality criteria, while keeping the investment and operating cost as low as possible. Although conceptual design and process control of activated sludge plants are key to ensuring these goals, they are still based on general empirical guidelines and operators' experience, dominated often by rule of thumb. This review paper discusses the rationale behind the use of Computational Fluid Dynamics (CFD) to model aeration, facilitating enhancement of treatment efficiency and reduction of energy input. Several single- and multiphase approaches commonly used in CFD studies of aeration tank operation, are comprehensively described, whilst the shortcomings of the modelling assumptions imposed to evaluate mixing and mass transfer in AS tanks are identified and discussed. Examples and methods of coupling of CFD data with biokinetics, accounting for the actual flow field and its impact on the oxygen mass transfer and yield of the biological processes occurring in the aeration tanks, are also critically discussed. Finally, modelling issues, which remain unaddressed, (e.g. coupling of the AS tank with secondary clarifier and the use of population balance models to simulate bubbly flow or flocculation of the activated sludge), are also identified and discussed. PMID:26615385

  8. Probabilistic parameter estimation of activated sludge processes using Markov Chain Monte Carlo.

    PubMed

    Sharifi, Soroosh; Murthy, Sudhir; Takács, Imre; Massoudieh, Arash

    2014-03-01

    One of the most important challenges in making activated sludge models (ASMs) applicable to design problems is identifying the values of its many stoichiometric and kinetic parameters. When wastewater characteristics data from full-scale biological treatment systems are used for parameter estimation, several sources of uncertainty, including uncertainty in measured data, external forcing (e.g. influent characteristics), and model structural errors influence the value of the estimated parameters. This paper presents a Bayesian hierarchical modeling framework for the probabilistic estimation of activated sludge process parameters. The method provides the joint probability density functions (JPDFs) of stoichiometric and kinetic parameters by updating prior information regarding the parameters obtained from expert knowledge and literature. The method also provides the posterior correlations between the parameters, as well as a measure of sensitivity of the different constituents with respect to the parameters. This information can be used to design experiments to provide higher information content regarding certain parameters. The method is illustrated using the ASM1 model to describe synthetically generated data from a hypothetical biological treatment system. The results indicate that data from full-scale systems can narrow down the ranges of some parameters substantially whereas the amount of information they provide regarding other parameters is small, due to either large correlations between some of the parameters or a lack of sensitivity with respect to the parameters. PMID:24384542

  9. Predominant bacteria in an activated sludge reactor for the degradation of cutting fluids

    SciTech Connect

    Baker, C.A.; Claus, G.W.; Taylor, P.A.

    1983-01-01

    For the first time, an activated sludge reactor, established for the degradation of cutting fluids, was examined for predominant bacteria. In addition, both total and viable numbers of bacteria in the reactor were determined so that the percentage of each predominant type in the total reactor population could be determined. Three samples were studied, and a total of 15 genera were detected. In each sample, the genus Pseudomonas and the genus Microcyclus were present in high numbers. Three other genera, Acinetobacter, Alcaligenes, and Corynebacterium, were also found in every sample but in lower numbers. In one sample, numerous appendage bacteria were present, and one of these, the genus Seliberia, was the most predominant organism in that sample. However, in the other two samples no appendage bacteria were detected. Six genera were found in this reactor which have not been previously reported in either cutting fluids in use or in other activated sludge systems. These genera were Aeromonas, Hyphomonas, Listeria, Microcyclus, Moraxella, and Spirosoma. None of the predominant bacterial belonged to groups of strict pathogens. 22 references, 6 figures, 3 tables.

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

    PubMed

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

    2016-01-01

    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. PMID:26439861

  11. The application of multi-objective optimization method for activated sludge process: a review.

    PubMed

    Dai, Hongliang; Chen, Wenliang; Lu, Xiwu

    2016-01-01

    The activated sludge process (ASP) is the most generally applied biological wastewater treatment approach. Depending on the design and specific application, activated sludge wastewater treatment plants (WWTPs) can achieve biological nitrogen (N) and phosphorus (P) removal, besides the removal of organic carbon substances. However, the effluent N and P limits are getting tighter because of increased emphasis on environmental protection, and the needs for energy conservation as well as the operational reliability. Therefore, the balance between treatment performance and cost becomes a critical issue for the operations of WWTPs, which necessitates a multi-objective optimization (MOO). Recent studies in this field have shown promise in utilizing MOO to address the multiple conflicting criteria (i.e. effluent quality, operation cost, operation stability), including studying the ASP models that are primarily responsible for the process, and developing the method of MOO in the wastewater treatment process, which facilitates better optimization of process performance. Based on a better understanding of the application of MOO for ASP, a comprehensive review is conducted to offer a clear vision of the advances, and potential areas for future research are also proposed in the field. PMID:26819377

  12. Formation of soluble microbial products (SMP) by activated sludge at various salinities.

    PubMed

    Li, Yan; Li, Ai-Min; Xu, Juan; Li, Wen-Wei; Yu, Han-Qing

    2013-02-01

    Soluble microbial products (SMP) present a significant component of effluent organic matter from biological wastewater treatment reactors, and can affect the membrane fouling and formation of disinfection by-products. Thus, SMP have attracted increasing concerns in wastewater treatment and reclamation. In this work, the formation of SMP by activated sludge at various NaCl concentrations is investigated by using fluorescence excitation-emission matrix (EEM) spectroscopy with parallel factor analysis (PARAFAC) and fluorescence regional integration (FRI). The results show that a high level of salinity decreases substrate removal efficiency and leads to an accumulation of SMP, especially proteins. Three components of SMP, one protein-like and two humic-acid-like components, are identified by PARAFAC, which exhibit different trends with the variation of NaCl concentration. FRI analysis reveals that the majority of protein fluorescence is attributed to tryptophan and tryptophan-like proteins, rather than tyrosine and tyrosine-like proteins. With an increase in NaCl concentration, the normalized volume percentages of tyrosine and tryptophan region increase, while those of humic- and fulvic-acid-like region decrease significantly. This work demonstrates that salinity affects the formation of SMP, and that EEM with PARAFAC in combination with FRI analysis is a useful tool to get insight into the formation of SMP by activated sludge. PMID:22622691

  13. Elucidating further phylogenetic diversity among the Defluviicoccus-related glycogen-accumulating organisms in activated sludge.

    PubMed

    McIlroy, Simon; Seviour, Robert J

    2009-12-01

    Glycogen-accumulating organisms (GAO) are thought to out-compete the polyphosphate-accumulating organisms (PAO) in activated sludge communities removing phosphate (P). Two GAO groups are currently recognized, the gammaproteobacterial Candidatus'Competibacter phosphatis', and the alphaproteobacterial Defluviicoccus vanus-related tetrad forming organisms (TFOs). Both are phylogenetically diverse based on their 16S rRNA sequences, with the latter currently considered to contain members falling into three distinct clusters. This paper identifies members of an additional fourth Defluviicoccus cluster from 16S rRNA gene clone library data obtained from a laboratory-scale activated sludge plant community removing P, and details FISH probes designed against them. Probe DF181A was designed to target a single sequence and DF181B designed against the remaining sequences in the cluster. Cells hybridizing with these probes in the biomass samples tested always appeared as either TFOs or in large clusters of small cocci. Members of the Defluviicoccus-related organisms were commonly found in full-scale wastewater treatments plants, sometimes as a dominant population. PMID:23765935

  14. Selective enrichment and characterization of a phosphorus-removing bacterial consortium from activated sludge.

    PubMed

    Hollender, J; Dreyer, U; Kornberger, L; Kämpfer, P; Dott, W

    2002-01-01

    Under alternating aerobic/anaerobic conditions and without additional carbon sources, a bacterial consortium consisting initially of 18 bacterial strains was obtained in a sequence batch reactor. The phosphorus removal capability could only be maintained using sterile filtrate of activated sludge as medium. The addition of calcium and magnesium salts, as well as vitamins and trace elements, to autoclaved sterile filtrate of activated sludge was not sufficient to achieve stable phosphorus removal. A further enrichment by subcultivation on solid, agar, freezing, and shortening of the aerobic and anaerobic phases led to a defined bacterial consortium consisting of four strains. On the basis of physiological and chemotaxonomic characterization, and partial 16S rRNA sequencing, one of the organisms was identified as Delftia acidovorans. A further isolate belonged to the Bacillus cereus group, and the third isolate was identified as Microbacterium sp.. The remaining strain seems to represent a new genus within the Flavobacteriaceae. Under continuous chemostat conditions, this consortium was able to remove up to 9.6 mg P/l phosphate in the aerobic phase and released up to 8.5 mg/l in the anaerobic phase. Up to 25 mg P-polyphosphate/g dry mass was stored under aerobic conditions. PMID:11831470

  15. Association of coliform bacteria with wastewater particles: impact of operational parameters of the activated sludge process.

    PubMed

    Loge, Frank J; Emerick, Robert W; Ginn, Tim R; Darby, Jeannie L

    2002-01-01

    The fraction of particles with associated coliform bacteria (PAC) in the activated sludge process was evaluated using a 16S rRNA oligonucleotide probe specific to the family Enterobacteriaceae. The PAC was found to decline exponentially with increasing mean cell residence times (MCRTs). The factors influencing the formation of PAC, identified with simplified mass balance relationships. are the concentration of particles, the concentration of dispersed (non-particle associated) coliform bacteria, and the MCRT. The concentration of dispersed coliform bacteria was found to decline with increasing MCRTs. The rate of decline was greater than the typical half-life attributed to endogenous decay, suggesting that other factors (e.g., predation by protozoa) influence the concentration of dispersed coliform bacteria, and subsequently the formation of PAC. Given that the association of targeted organisms with particles adversely impacts the performance of a disinfection system, studies targeted at the fate of organisms other than coliform bacteria in the activated sludge process are of paramount importance in assessing the health risks of post-disinfected effluents. PMID:11766816

  16. Continuous clarification and thickening of activated sludge by electrolytic bubbles under control of scale deposition.

    PubMed

    Cho, Kang Woo; Chung, Chong Min; Kim, Yun Jung; Chung, Tai Hak

    2010-05-01

    Electroflotation (EF) was investigated as a final clarification of an activated sludge process, to intensify its novel clarification and thickening efficiency. During operation of a biological reactor combined with an EF clarifier, deterioration of clarification efficiency was observed. Scale deposition on electrodes caused a coarse electrode surface, significantly increasing the size of the electrolytic bubbles. The average bubble size was initially 34 microm and increased to 80 microm after bulk cell electrolysis for 150 h. X-ray diffractometry and scanning electron microscopy further characterized the scale deposition as a cluster of calcite (CaCO(3)) and brucite (Mg(OH)(2)). Switching the polarity of electrical current clearly alleviated the increase of bubble size, when applied before scale growth. Under the control of scale deposition, excellent clarification was observed, with the effluent turbidity consistently lower than 2 NTU. An efficient thickening, with the concentration of return activated sludge higher than 15 g L(-1), was additional advantage of the EF clarifier. PMID:20071165

  17. Predominant Bacteria in an Activated Sludge Reactor for the Degradation of Cutting Fluids

    PubMed Central

    Baker, C. A.; Claus, G. W.; Taylor, P. A.

    1983-01-01

    For the first time, an activated sludge reactor, established for the degradation of cutting fluids, was examined for predominant bacteria. In addition, both total and viable numbers of bacteria in the reactor were determined so that the percentage of each predominant type in the total reactor population could be determined. Three samples were studied, and a total of 15 genera were detected. In each sample, the genus Pseudomonas and the genus Microcyclus were present in high numbers. Three other genera, Acinetobacter, Alcaligenes, and Corynebacterium, were also found in every sample but in lower numbers. In one sample, numerous appendaged bacteria were present, and one of these, the genus Seliberia, was the most predominant organism in that sample. However, in the other two samples no appendaged bacteria were detected. Six genera were found in this reactor which have not been previously reported in either cutting fluids in use or in other activated sludge systems. These genera were Aeromonas, Hyphomonas, Listeria, Microcyclus, Moraxella, and Spirosoma. None of the predominant bacteria belonged to groups of strict pathogens. Images PMID:16346426

  18. Formation of distinct soluble microbial products by activated sludge: kinetic analysis and quantitative determination.

    PubMed

    Ni, Bing-Jie; Fang, Fang; Xie, Wen-Ming; Xu, Juan; Yu, Han-Qing

    2012-02-01

    Soluble microbial products (SMP) released by microorganisms in bioreactors are classified into two distinct groups according to their different chemical and degradation kinetics: utilization-associated products (UAP) and biomass-associated products (BAP). SMP are responsible for effluent chemical oxygen demand or for membrane fouling of membrane bioreactor. Here an effective and convenient approach, other than the complicated chemical methods or complex models, is developed to quantify the formation of UAP and BAP together with their kinetics in activated sludge process. In this approach, an integrated substrate utilization equation is developed and used to determine UAP and their production kinetics. On the basis of total SMP measurements, BAP formation is determined with an integrated BAP formation equation. The fraction of substrate electrons diverted to UAP, and the content of BAP derived from biomass can then be calculated. Dynamic quantification data are obtained for UAP and BAP separately and conveniently. The obtained kinetic parameters are found to be reasonable as they are generally bounded and comparable to the literature values. The validity of this approach is confirmed by independent SMP production tests in six different activated sludge systems, which demonstrates its applicability in a wide range of engineered system regarding SMP production. This work provides a widely applied approach to determine the formation of UAP and BAP conveniently, which may offer engineers with basis to optimize bioreactor operation to avoid a high effluent soluble organics from SMP or SMP-based membrane fouling in membrane bioreactors. PMID:22185635

  19. Environmental biodegradation of haloarchaea-produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in activated sludge.

    PubMed

    Liu, Xiao-Bin; Wu, Lin-Ping; Hou, Jing; Chen, Jun-Yu; Han, Jing; Xiang, Hua

    2016-08-01

    Novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) copolymers produced by haloarchaea are excellent candidate biomaterials. However, there is no report hitherto focusing on the biodegradation of PHBHV synthesized by haloarchaea. In this study, an environmental biodegradation of haloarchaea-produced PHBHV films, with 10~60 mol% 3-hydroxyvalerate (3HV) composition and different microchemical structures, was studied in nutrition-depleted activated sludge. The changes in mass, molar mass, chemical composition, thermal properties, and surface morphology were monitored. The mass and molar mass of each film decreased significantly, while the PHA monomer composition remained unchanged with time. Interestingly, the sample of random copolymer PHBHV-2 (R-PHBHV-2) (3HV, 30 mol%) had the lowest crystallinity and was degraded faster than R-PHBHV-3 containing the highest 3HV content or the higher-order copolymer PHBHV-1 (O-PHBHV-1) possessing the highest surface roughness. The order of biodegradation rate was in the opposite trend to the degree of crystallizability of the films. Meanwhile, thermal degradation temperature of most films decreased after biodegradation. Additionally, the surface erosion of films was confirmed by scanning electron microscopy. The dominant bacteria probably responsible for the degradation process were identified in the activated sludge. It was inferred that the degradation rate of haloarchaea-produced PHBHV films mainly depended on sample crystallinity, which was determined by monomer composition and microchemical structure and in turn strongly influenced surface morphology. PMID:27098259

  20. Assessment of toxicity and biodegradability on activated sludge of priority and emerging pollutants.

    PubMed

    Tobajas, Montserrat; Verdugo, Verónica; Polo, Alicia M; Rodriguez, Juan J; Mohedano, Angel F

    2016-03-01

    Several methods for evaluating the toxicity and biodegradability of hazardous pollutants (chlorinated compounds, chemical additives and pharmaceuticals) have been studied in this work. Different bioassays using representative bacteria of marine and terrestrial ecosystems such as Vibrio fischeri and Pseudomonas putida have been used to assess the ecotoxicity. Activated sludge was used to analyse the effect of those pollutants in a biological reactor of a sewage treatment plant (STP). The results demonstrate that none of the compounds is toxic to activated sludge, except ofloxacin to P. putida. The additives tested can be considered moderately toxic according to the more sensitive V. fischeri assays, whereas the EC50 values of the pharmaceuticals depend on the specific microorganism used in each test. Regarding the biodegradability, respirometric measurements were carried out for fast biodegradability assessment and the Zahn-Wellens test for inherent biodegradability. The evolution of the specific oxygen uptake rate (SOUR) showed that only diethyl phthalate was easily biodegradable and acetylsalicylic acid was partially biodegradable (98% and 65% degradation, respectively). The persistence of dichloromethane, ofloxacin and hidrochlorothiazide was confirmed along the 28 days of the Zahn-Wellens test whereas 1,1,1-trichloroethane showed inherent biodegradability (74% removal). Most of the chlorinated compounds, pharmaceuticals, bisphenol A and ethylenediaminetetraacetic acid were partially degraded in 28 d with total organic carbon (TOC) reduction ranging from 21% to 51%. Sulphamethoxazole showed certain biodegradation (50% removal) with TOC decrease around 31%, which indicates the formation of non-biodegradable by-products. PMID:26243262

  1. Genomic features of uncultured methylotrophs in activated-sludge microbiomes grown under different enrichment procedures

    PubMed Central

    Fujinawa, Kazuki; Asai, Yusuke; Miyahara, Morio; Kouzuma, Atsushi; Abe, Takashi; Watanabe, Kazuya

    2016-01-01

    Methylotrophs are organisms that are able to grow on C1 compounds as carbon and energy sources. They play important roles in the global carbon cycle and contribute largely to industrial wastewater treatment. To identify and characterize methylotrophs that are involved in methanol degradation in wastewater-treatment plants, methanol-fed activated-sludge (MAS) microbiomes were subjected to phylogenetic and metagenomic analyses, and genomic features of dominant methylotrophs in MAS were compared with those preferentially grown in laboratory enrichment cultures (LECs). These analyses consistently indicate that Hyphomicrobium plays important roles in MAS, while Methylophilus occurred predominantly in LECs. Comparative analyses of bin genomes reconstructed for the Hyphomicrobium and Methylophilus methylotrophs suggest that they have different C1-assimilation pathways. In addition, function-module analyses suggest that their cell-surface structures are different. Comparison of the MAS bin genome with genomes of closely related Hyphomicrobium isolates suggests that genes unnecessary in MAS (for instance, genes for anaerobic respiration) have been lost from the genome of the dominant methylotroph. We suggest that genomic features and coded functions in the MAS bin genome provide us with insights into how this methylotroph adapts to activated-sludge ecosystems. PMID:27221669

  2. Fate of free and linear alcohol-ethoxylate-derived fatty alcohols in activated sludge.

    PubMed

    Federle, Thomas W; Itrich, Nina R

    2006-05-01

    Pure homologues of [1-14C] C12, C14, and C16 alcohols and the linear alcohol ethoxylates, AE [1-14C alkyl] C13E9 and C16E9 were tested in a batch-activated sludge die-away system to assess their biodegradation kinetics and to predict levels of free alcohol derived from AE biodegradation in treated effluent. First-order rates for primary biodegradation were similar for all alcohols (86-113 h(-1)) and were used to predict removal under typical treatment conditions. Predicted removals of fatty alcohols ranged from 99.76% to 99.85%, consistent with published field data. During the biodegradation of the AE homologues, lower than expected levels of fatty alcohol based upon the assumption that biodegradation occurs through central fission were observed. Rather than fatty alcohols, the major metabolites were polar materials resulting from omega oxidation of the alkyl chain prior to or concurrent with central cleavage. The amounts of free fatty alcohols that were formed from AEs in influent and escape into effluent were negligible due both to their rapid degradation and to the finding that formation of free alcohol through central cleavage is only a minor degradation pathway in activated sludge. PMID:16026837

  3. Degradation of cis- and trans-(4-methylcyclohexyl) methanol in activated sludge.

    PubMed

    Yuan, Li; Zhi, Wei; Liu, Yangsheng; Smiley, Elizabeth; Gallagher, Daniel; Chen, Xi; Dietrich, Andrea M; Zhang, Husen

    2016-04-01

    Crude (4-methylcyclohexyl)methanol (MCHM) caused extensive contamination of drinking water, wastewater, and the environment during the 2014 West Virginia Chemical Spill. However, information related to the environmental degradation of cis- and trans-4-MCHM, the main components of the crude 4-MCHM mixture, remains largely unknown. This study is among the first to investigate the degradation kinetics and transformation of 4-MCHM isomers in activated sludge. The 4-MCHM loss was mainly due to biodegradation to form carbon dioxide (CO2), plus acetic, propionic, isobutyric, and isovaleric acids with little contribution from adsorption. The biodegradation of 4-MCHM isomers followed the first-order kinetic model with half-lives higher than 0.50 days. Nitrate augmented the degradation of 4-MCHM isomers, while glucose and acetate decreased their degradation. One 4-MCHM-degrading bacterium isolated from activated sludge was identified as Acinetobacter bouvetii strain EU40 based on 16S rRNA gene sequences. This study will enhance the prediction of the environmental fate of 4-MCHM in water treatment systems. PMID:26745518

  4. Volatile fatty acid impacts on nitrite oxidation and carbon dioxide fixation in activated sludge.

    PubMed

    Oguz, Merve T; Robinson, Kevin G; Layton, Alice C; Sayler, Gary S

    2006-02-01

    Batch test were performed to assess nitrite removal, nitrate formation, CO2 fixation, gaseous nitrogen production and microbial density in activated sludge exposed to volatile fatty acid (VFA) mixtures. Nitrite removal and nitrate formation were both affected by the presence of VFAs, but to different degrees. Nitrate formation rates were reduced to a greater extent (79%) than nitrite removal rates (36%) resulting in an apparent unbalanced nitrite oxidation reaction. Since the total bacterial density and the nitrite oxidizing bacteria (NOB, Nitrospira) concentration remained essentially constant under all test conditions, the reduction in rates was not due to heterotrophic uptake of nitrogen or to a decrease in the NOB population. In contrast to the nitrogen results, VFAs were not found to impact CO2 fixation efficiency. It appeared that nitrite oxidation occurred when VFAs were present since the oxidation of nitrite provides energy for CO2 fixation. However, nitrate produced from the oxidation of nitrite was r