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1
Mijaylova-Nacheva, P., E. Ramírez-Camperos, and S. Cuevas-Velasco. "Treatment of organic synthesis wastewater using anaerobic packed bed and aerobic suspended growth bioreactors." Water Science and Technology 55, no. 7 (April 1, 2007): 235–43. http://dx.doi.org/10.2166/wst.2007.150.
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The performance of an anaerobic mesophilic packed bed reactor, with a mixture of GAC and tezontle, followed by an aerobic suspended growth system was studied for the treatment of organic chemical wastewater with a high COD concentration (22–29 g/L). The testing of the anaerobic–aerobic system was conducted in an experimental set-up for almost 2.5 years. Different operational conditions were evaluated. The anaerobic reactor showed performance stability and COD removals higher than 80% were obtained with loads up to 16.6 kg.m−3.d−1. The acclimation of the aerobic biomass to the substrate in the anaerobic effluent was very quick and COD removals higher than 94% were obtained even at high organic loads. The combined anaerobic–aerobic system allowed total COD removals higher than 99.5% and the accomplishment of the discharge requirements of 200 mgCOD/L when the anaerobic reactor was operated with loads of 8–11 kg.m−3.d−1 and the aerobic reactor with 0.33 kg.kg−1.d−1, being the total HRT of 4.4. The average TKN removal in the anaerobic–aerobic system was 97%, the average for the anaerobic reactor being 52% and that one for the aerobic system being 94%.
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Fahmy, M., E. Heinzle, and O. M. Kut. "Treatment of Bleaching Effluents in Aerobic/Anaerobic Fluidized Biofilm Systems." Water Science and Technology 24, no. 3-4 (August 1, 1991): 179–87. http://dx.doi.org/10.2166/wst.1991.0474.
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Biodegradation of chloroorganic compounds in real industrial bleaching effluents (chlorination and extraction), with adapted biofilm in fluidized sand bed reactors, was studied under aerobic and anaerobic conditions. The effluents were only diluted and supplied with mineral nutrients. Two reactor combinations were compared with a single stage aerobic digestor (AFB). In the anaerobic-aerobic reactors in series (AAS), the effluents were first treated anaerobically followed by an aerobic reactor in a single pass. In the anaerobic-aerobic recycle reactor (AAR), the reactor content was periodically moving back from aerobic to anaerobic fluidized beds. The reactors were running continuously for one year. The most significant differences observed were between aerobic and anaerobic single reactors. Generally anaerobiosis reduced performance in terms of global parameters (COD, NPOC, AOX). With a residence time of 18 h for each reactor, COD and AOX typically decreased by 15-32 % for each aerobic reactor system (AFB, AAS, AAR), whereas a decrease of typically 4-15 % was observed in the purely anaerobic system. From GC and GC/MS analysis it was evident that in the anaerobic reactors, 2,4,6-trichlorophenol was first converted to 2,4-dichlorophenol. In all three systems 2,4,6-trichlorophenol and dichlorophenols were almost completely removed.
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Haberl, R., K. Atanasoff, and R. Braun. "Anaerobic-Aerobic Treatment of Organic High-Strength Industrial Waste Water." Water Science and Technology 23, no. 10-12 (May 1, 1991): 1909–18. http://dx.doi.org/10.2166/wst.1991.0647.
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Within this research project a number of high strength organic waste waters was treated in anaerobic-aerobic working bench scale units and in small scale pilot plants. By this study problems with the anaerobic-aerobic technology should be solved, dimensioning parameters should be worked out, and the economy should be focused. For most of the sewages the anaerobic-aerobic treatment turned out to be possible although sometimes technical problems could be observed. Such problems occurred in the final aerobic stage in connection with wastes with a high content of N. They could be solved by a predenitrification stage. Fibreboard sewage was taken as an example for wastes containing persistent substances; different anaerobic processes were tested, it turned out that a twostage anaerobic treatment is necessary to stabilize the process. The economic calculations proved the anaerobic-aerobic treatment to be preferable if some conditions are considered.
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Jahren, Sigrun J., and Hallvard Ødegaard. "Treatment of Thermomechanical Pulping (TMP) Whitewater in Thermophilic (55°C) Anaerobic-Aerobic Moving Bed Biofilm Reactors." Water Science and Technology 40, no. 8 (October 1, 1999): 81–89. http://dx.doi.org/10.2166/wst.1999.0391.
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Thermomechanical pulping whitewater was treated in an anaerobic followed by an aerobic Kaldnes moving bed biofilm reactor at 55°C. The anaerobic reactor was mixed by gas circulation and the aerobic reactor was mixed by aeration. The anaerobic reactor was started with mesophilic inoculum, while the aerobic reactor was started without inoculation. The reactors were operated on molasses water for one and a half years before the experiment was started. Total biomass concentrations (suspended and attached) were 3.3 g VSS/L in the anaerobic reactor and 1.6 g VSS/L in the aerobic reactor when starting feeding the reactors with TMP whitewater. After 7 months of operation the biomass concentrations had reached 5.5 and 6.5 g VSS/L in the anaerobic and aerobic reactors, respectively. The CODsol removals in the anaerobic reactor were around 30 % at loading rates up to 7 kg CODsol/m3d, and over-all CODsol removals of about 60 % were achieved. The results show that the anaerobic-aerobic moving bed biofilm process could be feasible for the thermophilic treatment of thermomechanical pulping whitewater.
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Gerards, R., W. Gils, and L. Vriens. "Upgrading of existing aerobic plants with the LUCAS anaerobic system based on full-scale experiences." Water Science and Technology 52, no. 4 (August 1, 2005): 39–46. http://dx.doi.org/10.2166/wst.2005.0085.
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It has been demonstrated that the combination of anaerobic–aerobic treatment is the best technological and economical solution for the treatment of high loaded wastewater. Where in the past aerobic treatment systems were still very acceptable due to the very good treatment efficiency, simplicity and robustness of the technology, this has, in most cases, been changed due to very stringent sludge disposal legislation. The anaerobic pretreatment takes care of approximately 80–90% of the overall treatment efficiency at high loading rates and low sludge production and low energy costs. The aerobic posttreatment takes care of the absolute high removal efficiency and nitrogen and phosphorus removal. Because of the low organic loading rate of the aerobic posttreatment also in this stage the sludge production is low. The combination of anaerobic–aerobic treatment results in a compact system capable of reaching high treatment efficiency at low sludge production and lower energy consumption. Waterleau Global Water Technology has developed LUCAS® anaerobic–aerobic system that combines an Upflow Anaerobic Sludge Blanket (UASB) reactor with an aerobic, constant-level cyclic activated sludge system, which is very suitable for the treatment of high loaded wastewaters in general and brewery waste water in particular. It has been proven from several full scale upgrading projects that the UASB system is best suitable for implementation in the aerobic plants that have to be extended in capacity.
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Satoh, H., Y. Iwamoto, T. Mino, and T. Matsuo. "Activated sludge as a possible source of biodegradable plastic." Water Science and Technology 38, no. 2 (July 1, 1998): 103–9. http://dx.doi.org/10.2166/wst.1998.0115.
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Polyhydroxyalkanaote (PHA) is known to be temporarily stored by microorganisms in activated sludge especially in the anaerobic-aerobic processes. When PHA is extracted from activated sludge, it is a thermoplastic with the remarkable characteristics of biodegradability. We investigated the possibility of using activated sludge for the production of PHA, focusing on increasing the PHA content of activated sludge. Activated sludge from laboratory scale anaerobic-aerobic reactors accumulated PHA of around 20% under anaerobic conditions and up to 33% under aerobic conditions. In order to further increase the PHA content of activated sludge, we introduced the “microaerophilic-aerobic” process, where a limited amount of oxygen is supplied into the anaerobic zone of the anaerobic-aerobic process. Activated sludge acclimatized in the microaerophilic-aerobic process accumulated PHA of as much as 62% of sludge dry weight. The “microaerophilic-aerobic” process was demonstrated to be an effective process for the enrichment of PHA-accumulating microorganisms.
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Bi, Li Jun, Jing Yang, and Shi Quan Sun. "Study on Phosphorus Release from Sediment Control by In Situ Control Technology." Advanced Materials Research 374-377 (October 2011): 899–904. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.899.
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This paper test to processing lakes sediment by three kinds of in-situ control technology which including aeration, zeolite capping and calcium nitrate in situ treatments, and it study the influence of phosphorus release from sediment. The test results showed: (1) under anaerobic conditions, the phosphorus release content is as 4.26 times as it under aerobic conditions. Under aerobic condition (dissolved oxygen saturation ≥ 20%), the Dissolved oxygen is not important for phosphorus release in sediments.（2）zeolite capping can effectively control the phosphorus release from sediment, but Dissolved oxygen is important for that. Under dynamic condition, the phosphorus release content is stability.（3）Under aerobic conditions or anaerobic conditions, calcium nitrate in situ treatments can effectively control the phosphorus release from sediment. Under aerobic conditions, the phosphorus release content reduce by 53.6%.Under anaerobic conditions, it reduce by 83.4%.(4) The control effects of the phosphorus release content by three kinds of in-situ control technology was followed: under anaerobic condition, calcium nitrate in-situ treatment > zeolite capping> untreated; and under aerobic condition, calcium nitrate in-situ treatment > zeolite capping > aeration ≥ untreated; and under hydrodynamic condition, calcium nitrate in-situ treatment >zeolite coverage>zeolite capping> aeration >untreated.
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Rosadi, Maulana Yusup, Toshiro Yamada, Hudori Hudori, Hiroto Tamaoki, and Fusheng Li. "Characterization of dissolved organic matter extracted from water treatment sludge." Water Supply 20, no. 6 (June 9, 2020): 2194–205. http://dx.doi.org/10.2166/ws.2020.120.
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Abstract The characteristics of dissolved organic matter (DOM) that formed during the aerobic and anaerobic incubation of drinking water treatment sludge stored at different temperatures (5 °C, 20 °C, 40 °C) for long periods (7, 14, and 21 days) were investigated. Anaerobic incubation at high temperatures with prolonged storage was found to result in higher organic content than aerobic incubation (3.6–6.8 times at 40 °C). The high temperatures caused changes in the DOM fractions, with humic-like substances mainly formed in aerobic incubation and protein-like substances in anaerobic incubation. Results showed that the fluorescence intensity of humic-like and protein-like substances increased by 45% and 22%, respectively, at the end of the anaerobic incubation period. The UV-absorbing DOM constituents in aerobic incubation had lower molecular weights and were more heterogeneous than those in anaerobic incubation.
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Ferguson, John F. "Anaerobic and Aerobic Treatment for AOX Removal." Water Science and Technology 29, no. 5-6 (March 1, 1994): 149–62. http://dx.doi.org/10.2166/wst.1994.0710.
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A two-year study has focused on AOX removal from bleaching wastewaters in anaerobic and aerobic biological treatment, using bench scale bioreactors operated in parallel and in series. Significantly higher removals have been found in anaerobic than in aerobic treatment. Earlier work with dilute kraft bleaching wastes has been extended in additional laboratory tests and at a nearby kraft mill. 50-75% fractions of bleaching wastes were treated. Toxicity in the anaerobic process was encountered at 85% bleach waste fractions. Total AOX removal experienced in aerobic treatment is 30-35%, in anaerobic treatment 40-45%, and in an anaerobic/aerobic sequence 50-55%. Percentage removals were not sensitive to the fraction of bleaching wastewater. Several process modifications were attempted to try to obtain higher removals with only marginal success. Studies at a kraft mill confirmed the AOX removals that had been found in lab studies. AOX removal occurs by several mechanisms. There is a very significant chemical or abiotic degradation that occurs after neutralization, perhaps enhanced by reductants or other inorganic salts. Biological processes are much more significant in anaerobic than in aerobic treatment. Anaerobic reductive dehalogenation affects specific chlorinated compounds and catalyzed AOX degradation is facilitated by reduced coenzymes that are produced by bacteria. Removal by sorption or insolubilization is relatively minor in aerobic and anaerobic processes.
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Frigon, J. C., R. Cimpoia, and S. R. Guiot. "Sequential anaerobic/aerobic biotreatment of bark leachate." Water Science and Technology 48, no. 6 (September 1, 2003): 203–9. http://dx.doi.org/10.2166/wst.2003.0398.
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Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96Ð98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols.
11
You, H. S., C. C. Tseng, M. J. Peng, S. H. Chang, Y. C. Chen, and S. H. Peng. "A novel application of an anaerobic membrane process in wastewater treatment." Water Science and Technology 51, no. 6-7 (March 1, 2005): 45–50. http://dx.doi.org/10.2166/wst.2005.0620.
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The applications of membrane processes in anaerobic biological wastewater treatment still have some limitations due to severe membrane scaling and fouling, although they have been proven to achieve superior COD removal and biomass retention. An innovative anaerobic membrane process for wastewater treatment was conducted to control the membrane scaling problems. The process comprises an anaerobic reactor, an aerobic reactor, and a membrane separation tank. Anaerobic sludge from a full-scale UASB reactor treating food wastewater was inoculated to anaerobic and aerobic reactor to purify synthetic wastewater consisting of glucose and sodium acetate. The anaerobic reactor was operated in a sludge bed type without three-phase separator. The aerobic reactor can eliminate residual organics from the anaerobic reactor effluent using facultative microorganisms. To provide solid-liquid separation, hollow fiber ultrafiltration module was submerged in the separation tank. The results clearly show that the anaerobic membrane process combined methanogenic and aerobic COD reduction is a stable system. No fatal scaling was found after two months of operation even without chemical cleaning for the membrane. It was also found that inorganic precipitates formed in the aerobic reactor were reduced due to CO2 stripping in aerobic reactor. Another important finding was that the inorganic precipitates were entrapped into facultative aerobes floc. The ash/SS ratio of aerobes floc increased from 0.17 to 0.55 after 50 days of operation, which confirms this phenomenon. Based on our investigation, the new process can control scaling effectively to extend the membrane application in anaerobic treatment.
12
Bode, H. "Anaerobic-Aerobic Treatment of Industrial Wastewater." Water Science and Technology 20, no. 4-5 (April 1, 1988): 189–98. http://dx.doi.org/10.2166/wst.1988.0166.
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The paper evaluates the question of whether a combined anaerobic-aerobic or a solely aerobic treatment of some particular industrial wastewaters leads to better results. Therefore three different industrial wastewaters were treated in two different process lines: one line consisted of anaerobic treatment prior to aerobic treatment and in the other, only aerobic treatment was applied. The experiments were run with wastewater from:–the pectin industry–the sugar industry (beet sugar)–the animal pulp industry. The data presented in this paper were gained from experimental work which was conducted over a period of two years. Different scales of treatment plants were used. The anaerobic treatment was done in full- and semitechnical scale reactors, while the aerobic treatment took place in labscale and semitechnical scale plants. Surprisingly in all three cases the solely aerobic treatment led to slightly better results in terms of residual pollution. Finally the paper presents data gained from a recently built, full-scale anaerobic-aerobic process which treats pectin waste. The aerobic stage of the process was designed on the basis of the results from the experimental work which was mentioned above. The results from the former experimental work and from the full-scale operation are compared.
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Bernet, N., N. Delgenès, J. P. Delgenès, and R. Moletta. "SBR as a relevant technology to combine anaerobic digestion and denitrification in a single reactor." Water Science and Technology 43, no. 3 (February 1, 2001): 209–14. http://dx.doi.org/10.2166/wst.2001.0139.
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Two laboratory-scale sequencing batch reactors were used to study biological treatment of carbon and nitrogen in a new combined anaerobic-aerobic system. Piggery wastewater was used as a model effluent. The anaerobic reactor, fed with raw wastewater and nitrite/nitrate recycling from the aerobic reactor, carried out denitrification and anaerobic digestion of organic carbon. In the aerobic reactor, organic carbon removal and nitrification of ammonia to mainly nitrite occurred. Three recycle-to-influent ratios from1 to 3 were tested. The higher the recycle-to-influent ratio, the lower the concentrations of nitrogen oxides in the final effluent. Carbon removal efficiency was quite stable, whatever the ratio. However, the effect of this ratio was attenuated because of denitrification in the aerobic reactor, which increased the performances of the process. The use of sequencing batch reactors was essential to apply the configuration proposed, in order to combine denitrification and methanogenesis that require antagonistic conditions.
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Tanaka, Naoya, and Thorkild Hvitved-Jacobsen. "Transformations of wastewater organic matter in sewers under changing aerobic/anaerobic conditions." Water Science and Technology 37, no. 1 (January 1, 1998): 105–13. http://dx.doi.org/10.2166/wst.1998.0026.
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Transformations of organic matter in domestic wastewater under changing aerobic/anaerobic conditions were studied in laboratory scale reactors and in a real pressure sewer emphasizing measurements of oxygen utilization rate (OUR). During 3-10 hours of anaerobic conditions, the aerobic, heterotrophic biomass was maintained and a net production of readily biodegradable substrate originating from hydrolyzable substrate was observed. A process model description which includes aerobic and anaerobic processes in the bulk water phase as well as in the biofilm was presented and model parameters were determined from OUR measurements. Based on experimental findings, it was possible to simulate wastewater quality changes in terms of organic matter under transient aerobic/anaerobic conditions in sewer systems.
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Mihopoulos, P. G., M. T. Suidan, and G. D. Sayles. "Complete remediation of PCE contaminated unsaturated soils by sequential anaerobic-aerobic bioventing." Water Science and Technology 43, no. 5 (March 1, 2001): 365–72. http://dx.doi.org/10.2166/wst.2001.0325.
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Bioventing principles have been applied to completely dechlorinate tetrachloroethylene vapors in the unsaturated zone in a sequential anaerobic-aerobic pattern. The aerobic step yields trans-DCE and VC as PCE reductive dechlorination byproducts, while TCE and cis-DCE are observed as intermediates. The aerobic step results in rapid oxidation of the VC and trans-DCE to carbon dioxide. Hydrogen was delivered in the gas phase as a reducing agent for the anaerobic step at levels of 1%, and oxygen at 4.2% was used as an electron acceptor in the aerobic step. PCE and VC half lives in the anaerobic and aerobic steps respectively, where less than 10 min.
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Rintala, J., and R. Lepistö. "Thermophilic Anaerobic–Aerobic and Aerobic Treatment of Kraft Bleaching Effluents." Water Science and Technology 28, no. 2 (July 1, 1993): 11–16. http://dx.doi.org/10.2166/wst.1993.0067.
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Thermophilic anaerobic-aerobic treatment of bleach kraft mill effluent (BKME) at 55°C was studied using reactors partially packed with polyurethane carrier material. The wastewater was a mixture of chlorination stage and alkaline extraction stage effluents from softwood pulping. Both the thermophilic anaerobic and aerobic treatments provided about 40-45% COD and AOX removals at loading rates of about 13-2.5 kg COD m−3 d−1, which corresponded with hydraulic retention times of 17.6-30 h. The aerobic post-treatment removed less than 10% of the COD and AOX present in the anaerobically treated BKME.
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Panswad, T., A. Techovanich, and J. Anotai. "Comparison of dye wastewater treatment by normal and anoxic+anaerobic/aerobic SBR activated sludge processes." Water Science and Technology 43, no. 2 (January 1, 2001): 355–62. http://dx.doi.org/10.2166/wst.2001.0111.
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In this research, the effects of different color intensities, anoxic+anaerobic times and types of substrate on color removal effectiveness were studied using 16-litre bench scale sequencing batch reactor (SBR) anoxic+anaerobic/aerobic models. The systems were fed with a synthetic wastewater containing 500 mg/l of COD, 50 mg/l of N, 15 mg/l of P along with 10, 40 and 80 mg/l of reactive diazo Remazol Black B dye. The anoxic+anaerobic/aerobic periods were 0/11 (normal aerobic SBR), 2/9, 4/7 and 8/3 hours, respectively. The color removal occurred mainly under the anaerobic environment, while a slight attenuation was noticed under the aerobic condition. A better decolorization could be achieved with a longer anoxic+anaerobic period. The sodium acetate was a slightly better co-substrate for the color removal than glucose. The decolorization efficiency dwindled as the fed dye concentration increased, but the overall color removal leaned in the opposite direction. The phosphorus removal of the anoxic+anaerobic/aerobic systems was outstanding, whereas only 50% removal was achieved for the aerobic process. A dye concentration of up to 80 mg/l did not have any significant impact on the performance of the polyphosphate accumulating organisms (PAOs). The removal of organic carbon and TKN was comparable among all experiments regardless of system configurations, color intensities and types of substrate.
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Kortekaas, S., H. S. Doma, S. A. Potapenko, J. A. Field, and G. Lettinga. "Sequenced Anaerobic-Aerobic Treatment of Hemp Black Liquors." Water Science and Technology 29, no. 5-6 (March 1, 1994): 409–19. http://dx.doi.org/10.2166/wst.1994.0734.
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This study evaluates the sequenced anaerobic-aerobic treatment of hemp bark and hemp stem wood black liquors with respect to COD removal efficiency and detoxification. Anaerobic toxicity assays revealed that soda pulping liquors derived from hemp are just as toxic as those derived from wood. Hemp bark and stem wood black liquors caused 50% inhibition at concentrations of 5.9 and 4.5 g COD/l, respectively. Long term experiments were conducted in lab-scale upflow anaerobic sludge blanket (UASB) reactors at 30°C. Black liquor was fed at sub-toxic concentrations (< 4 g COD/l). In the bark column loadings were applied up to 17.5 g COD/l*d with COD and BOD5 efficiencies of 56.0 and 87.9%, respectively. In the stem wood column loadings up to 18.4 g COD/l*d were reached with COD and BOD5 efficiencies of 42.3 and 81.0%, respectively. Aerobic post-treatment displayed only minor extra COD removal and a strong increase of color levels. After sequenced anaerobic-aerobic treatment, the COD removal was 70.9 and 58.4% for bark and stem wood liquor, respectively, whereas the BOD5 removal exceeded 98%. Strong detoxification was accomplished after anaerobic-aerobic treatment, as was demonstrated by anaerobic toxicity assays. After anaerobic-aerobic treatment bemp bark and stem wood black liquors caused 50% inhibition at concentrations of 135 and 21.5 g COD/l, respectively.
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Wang, X., T. H. Mize, F. M. Saunders, and S. A. Baker. "Biotreatability test of bleach wastewaters from pulp and paper mills." Water Science and Technology 35, no. 2-3 (February 1, 1997): 101–8. http://dx.doi.org/10.2166/wst.1997.0492.
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Research is focused on an integrated way to simultaneously optimize the bleaching operations and subsequent wastewater treatment for pulp and paper mills. Bleach wastewaters from ClO2-bleached pulping studies at Institute of Paper Science and Technology (IPST) were used as the feed for batch reactors to test and rank the treatability and kinetics. The key aspect of the system is the use of sequential anaerobic/aerobic phases to enhance reductive dehalogenation of chloro-organic materials. Two continuous reactor systems, one operated in an anaerobic-aerobic mode and a second in an aerobic-aerobic mode, received bleaching wastewater obtained from a full-scale plant. Acclimated cultures from both continuous reactors were used to quantify the AOX (Adsorbable Organic Halide) and COD removal from various bleaching wastewaters. In general, the sequential anaerobic/aerobic treatment of bleach wastewater can improve both biotreatability and degradation rates.
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Keller, J., and K. Hartley. "Greenhouse gas production in wastewater treatment: process selection is the major factor." Water Science and Technology 47, no. 12 (June 1, 2003): 43–48. http://dx.doi.org/10.2166/wst.2003.0626.
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Many practical design and operating decisions on wastewater treatment plants can have significant impacts on the overall environmental performance, in particular the greenhouse gas (GHG) emissions. The main factor in this regard is the use of aerobic or anaerobic treatment technology. This paper compares the GHG production of a number of case studies with aerobic or anaerobic main and sludge treatment of domestic wastewater and also looks at the energy balances and economics. This comparison demonstrates that major advantages can be gained by using primarily anaerobic processes as it is possible to largely eliminate any net energy input to the process, and therefore the production of GHG from fossil fuels. This is achieved by converting the energy of the incoming wastewater pollutants to methane which is then used to generate electricity. This is sufficient to power the aerobic processes as well as the mixing etc. of the anaerobic stages. In terms of GHG production, the total output (in CO2 equivalents) can be reduced from 2.4 kg CO2/kg CODremoved for fully aerobic treatment to 1.0 kg CO2/kg CODremoved for primarily anaerobic processes. All of the CO2 produced in the anaerobic processes comes from the wastewater pollutants and is therefore greenhouse gas neutral, whereas up to 1.4 kg CO2/kg CODremoved originates from power generation for the fully aerobic process. This means that considerably more CO2 is produced in power generation than in the actual treatment process, and all of this is typically from fossil fuels, whereas the energy from the wastewater pollutants comes primarily from renewable energy sources, namely agricultural products. Even a change from anaerobic to aerobic sludge treatment processes (for the same aerobic main process) has a massive impact on the CO2 production from fossil fuels. An additional 0.8 kg CO2/kg CODremoved is produced by changing to aerobic sludge digestion, which equates for a typical 100,000 EP plant to an additional production of over 10 t CO2 per day. Preliminary cost estimates confirm that the largely anaerobic process option is a fully competitive alternative to the mainly aerobic processes used, while achieving the same effluent quality.
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Lu, Mang, Li-Peng Gu, and Wen-Hao Xu. "Treatment of petroleum refinery wastewater using a sequential anaerobic–aerobic moving-bed biofilm reactor system based on suspended ceramsite." Water Science and Technology 67, no. 9 (May 1, 2013): 1976–83. http://dx.doi.org/10.2166/wst.2013.077.
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In this study, a novel suspended ceramsite was prepared, which has high strength, optimum density (close to water), and high porosity. The ceramsite was used to feed a moving-bed biofilm reactor (MBBR) system with an anaerobic–aerobic (A/O) arrangement to treat petroleum refinery wastewater for simultaneous removal of chemical oxygen demand (COD) and ammonium. The hydraulic retention time (HRT) of the anaerobic–aerobic MBBR system was varied from 72 to 18 h. The anaerobic–aerobic system had a strong tolerance to shock loading. Compared with the professional emission standard of China, the effluent concentrations of COD and NH3-N in the system could satisfy grade I at HRTs of 72 and 36 h, and grade II at HRT of 18 h. The average sludge yield of the anaerobic reactor was estimated to be 0.0575 g suspended solid/g CODremoved. This work demonstrated that the anaerobic–aerobic MBBR system using the suspended ceramsite as bio-carrier could be applied to achieving high wastewater treatment efficiency.
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Thirumurthi, Dhandapani, Thomas P. Austin, Ramalingaiah, and Sudhir Khakhria. "Anaerobic/Aerobic Treatment of Municipal Landfill Leachate." Water Quality Research Journal 21, no. 1 (February 1, 1986): 8–20. http://dx.doi.org/10.2166/wqrj.1986.002.
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Abstract Laboratory-model studies were conducted to develop design guidelines for treatment of high-strength leachate (23,000 mg COD/L, 17,500 mg BOD/L, 8,000 mg TOC/L, 1,000 mg Fe/L and 80 mg Zn/L) generated from a landfill site that serves the metropolitan area of Halifax, Canada. The selected processes included two treatment systems, I and II. System I consisted of an anaerobic fixed film reactor (AFFR1), the effluent from which was further treated by an aerated lagoon and a settling lagoon in parallel. System II consisted of a second AFFR, but was not followed by any other treatment. The AFFR’s were upflow cylindrical tanks with plastic "Tellerette" rings which provided the fixed surface. This is the first known investigation which utilized the rings (patented by Pennwalt Corporation) that are manufactured as packing material in air pollution control devices. The pH-adjusted, settled and nutrient-supplemented leachate (pre-treatment step) was added to AFFR1, and AFFR2 to maintain organic loads of about 2 and 1.6 kg COD/day.m3, respectively. The two fixed film reactors were kept at 32 ± 1°C and the two lagoons at 20 ± 2°C. The 12-week study showed that system Ia, consisting of pre-treatment, AFFR1, and aerated lagoon, resulted in the best performance; system Ib, (pre-treatment, AFFR1 and settling lagoon) generated the second best effluent, followed by System II, which produced an inferior effluent. System la resulted in greater than 99% removal of COD, BOD, TOC, Fe and Zn. System Ib removed between 98% and 99% of COD and TOC and more than 99% of BOD, Fe and Zn. System II (pre-treatment and AFFR2), however, could remove between 97% and 98% of COD and TOC, and in excess of 99% of BOD, Fe and Zn. Similar data for the remaining 36 parameters are also included. Biogas generated by the two AFFR’s ranged from about 0.4 to 0.57 m3 per kg of COD destroyed. Comparisons have been made between the performance potentials, capital and operating costs and energy requirements, of the Systems Ia, Ib and II.
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Tanaka, Toshihiro, Masayoshi Kitagawa, and Eiichi Ohkubo. "Energy Saving, High Biological Phosphorus Removal and Improvement of Sludge Settleability on Full-Scale Anaerobic–Aerobic Activated Sludge Process." Water Science and Technology 23, no. 4-6 (February 1, 1991): 801–10. http://dx.doi.org/10.2166/wst.1991.0531.
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An anaerobic-aerobic process was modified from a conventional process used in municipal sewage works to enable phosphorus removal and improving sludge settleability. Research was conducted in three sewage works in comparison with the conventional process. The phosphorus removal efficiency by the anaerobic-aerobic process was higher. The T-P removal ratio ranged 80 - 90% and T-P concentration of the effluent was almost below 1 mg/l, when the average T-P/BOD ratio was 0.04. The removal efficiency of other water quality and excess sludge generation ratio were almost equal in both processes. The anaerobic-aerobic process is not only effective for improving the sludge settleability but also enables wastewater treatment with less quantity of air (approx. 20% reduction). Even including the power consumed for mixing, the anaerobic-aerobic process used up less power (approx. 12%).
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Franca, R. D. G., J. Ortigueira, H. M. Pinheiro, and N. D. Lourenço. "Effect of SBR feeding strategy and feed composition on the stability of aerobic granular sludge in the treatment of a simulated textile wastewater." Water Science and Technology 76, no. 5 (May 20, 2017): 1188–95. http://dx.doi.org/10.2166/wst.2017.300.
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Treatment of the highly polluting and variable textile industry wastewater using aerobic granular sludge (AGS) sequencing batch reactors (SBRs) has been recently suggested. Aiming to develop this technology application, two feeding strategies were compared regarding the capacity of anaerobic–aerobic SBRs to deal with disturbances in the composition of the simulated textile wastewater feed. Both a statically fed, anaerobic–aerobic SBR and an anaerobic plug-flow fed, anaerobic–aerobic SBR could cope with shocks of high azo dye concentration and organic load, the overall chemical oxygen demand and color removal yields being rapidly restored to 80%. Yet, subsequent azo dye metabolite bioconversion was not observed, along the 315-day run. Moreover, switching from a starch-based substrate to acetate in the feed composition deteriorated AGS stability. Overall, the plug-flow fed SBR recovered more rapidly from the imposed disturbances. Further research is needed towards guaranteeing long-term AGS stability during the treatment of textile wastewater.
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Dohányos, Michal, Jana Zábranská, and Pavel Jenícek. "Innovative technology for the improvement of the anaerobic methane fermentation." Water Science and Technology 36, no. 6-7 (September 1, 1997): 333–40. http://dx.doi.org/10.2166/wst.1997.0608.
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The intensification method of anaerobic methane fermentation of sludges, based on the stimulation activity of cell lysate, was studied. The effect of lysate is caused by the still remaining activity of released enzymes and by the stimulating properties of other compounds that are present inside the cells. The anaerobic cell lysate was prepared by a thermal treatment of anaerobic sludge and the aerobic cell lysate by a partial mechanical destruction of cells of the excess activated sludge by a special adapted thickening centrifuge. The use of cell lysate as a stimulating agent was examined in the laboratory experiments of anaerobic degradation of simple organic compounds (glucose, acetate, formate and propionate) and of complex substrates as municipal raw sludge, excess activated sludge and some pharmaceutical organic wastes. The results show a significant improvement of the removal rates of substrates and the enhancement of methane production in all cases of lysate addition. In the fermentation of raw sludges and pharmaceutical wastes with anaerobic lysate, the increment of the methane yield ranges from 38.2–61.8% and 20.2–36.7% respectively. The aerobic lysate increased the methane yield of excess activated sludge and of its mixture with primary sludge at the range of 17.1–86.4% and 24% respectively.
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Abiri, Fardin, Narges Fallah, and Babak Bonakdarpour. "Sequential anaerobic–aerobic biological treatment of colored wastewaters: case study of a textile dyeing factory wastewater." Water Science and Technology 75, no. 6 (November 22, 2016): 1261–69. http://dx.doi.org/10.2166/wst.2016.531.
Full textAbstract:
In the present study the feasibility of the use of a bacterial batch sequential anaerobic–aerobic process, in which activated sludge was used in both parts of the process, for pretreatment of wastewater generated by a textile dyeing factory has been considered. Activated sludge used in the process was obtained from a municipal wastewater treatment plant and adapted to real dyeing wastewater using either an anaerobic-only or an anaerobic–aerobic process over a period of 90 days. The use of activated sludge adapted using the anaerobic–aerobic process resulted in a higher overall decolorization efficiency compared to that achieved with activated sludge adapted using the anaerobic-only cycles. Anaerobic and aerobic periods of around 34 and 22 hours respectively resulted in an effluent with chemical oxygen demand (COD) and color content which met the standards for discharge into the centralized wastewater treatment plant of the industrial estate in which the dyeing factory was situated. Neutralization of the real dyeing wastewater and addition of carbon source to it, both of which results in significant increase in the cost of the bacterial treatment process, was not found to be necessary to achieve the required discharge standards.
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Mulder, R., T. L. F. M. Vereijken, C. M. T. J. Frijters, and S. H. J. Vellinga. "Future perspectives in bioreactor development." Water Science and Technology 44, no. 8 (October 1, 2001): 27–32. http://dx.doi.org/10.2166/wst.2001.0457.
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The paper discusses conversion capacities of both anaerobic and aerobic wastewater treatment systems in relation to growth kinetics, hydrodynamics and biomass concentration. In the current modern anaerobic high-rate reactors the conversion potentials are optimally exploited. This is not yet true for aerobic systems since operation of aerobic systems under conditions of low biomass growth reduces the maximum applicable loading rates significantly. Both the concept of granulation and the introduction of fluidised bed systems have increased conversion capacities for both anaerobic and aerobic systems significantly. One of the latest development concerns the SBR with granular biomass. The grazing concept, in which ciliates convert aerobically grown dispersed cells, offers a possibility for significant improvement of aerobic systems. In the fields of psychrophilic and thermophilic anaerobic treatment, specific reactor development may contribute to further enhance volumetric conversion capacities. Due to reduced water usage, both COD and salt concentrations tend to increase for industrial effluents. As a consequence, there is a need for the development of anaerobic reactors retaining flocculant biomass. The membrane bioreactors offer a solution for certain niches in wastewater treatment. However the oxygen transfer economy is poor. There is a need for fundamental knowledge development to obtain a realistic image of this technology.
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Tan, N. C., A. Borger, P. Slenders, A. Svitelskaya, G. Lettinga, and J. A. Field. "Degradation of azo dye Mordant Yellow 10 in a sequential anaerobic and bioaugmented aerobic bioreactor." Water Science and Technology 42, no. 5-6 (September 1, 2000): 337–44. http://dx.doi.org/10.2166/wst.2000.0533.
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Complete biodegradation of azo dyes requires an anaerobic and aerobic step, in the anaerobic step sulfonated azo dyes (SADs) are reduced, yielding (sulfonated) aromatic amines ((S)AAs) which can be degraded aerobically. The complete biodegradation of the SAD Mordant Yellow 10 (MY10) was studied in a sequential anaerobic and aerobic bioreactor. Anaerobically, MY10 was reductively cleaved and the resulting aromatic amines, 5-aminosalicylic acid (5-ASA) and sulfanilic acid (SA), were both recovered in high stoichiometric yields. One of the AAs, 5-ASA, was readily degraded under aerobic conditions. However, SA was not degraded aerobically in the continuous experiment because no SA-degrading bacterial activity was present in the system. Therefore, a SA-degrading enrichment culture derived from Rhine sediment was used as an inoculum source. This enrichment culture was bioaugmented into the aerobic reactor by increasing the hydraulic retention time (HRT), thus enabling SA-degrading activity to develop and maintain in the aerobic reactor. After decreasing the HRT, the SA-degrading activity remained in the bioreactor and the stoichiometric recovery of sulfate (a SA biodegradation product) indicated the mineralization of SA after bioaugmentation. Batch experiments with aerobic reactor sludge confirmed the biodegradation of SA and 5-ASA. The sequential anaerobic and aerobic bioreactor was able to completely remove the sulfonated azo dye MY10 at a maximum loading rate of 210 mg MY10 (lreactor d)-1 after the appropriate microorganisms for aerobic degradation of SA were bioaugmented into the aerobic bioreactor.
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Salkinoja-Salonen, M. S., R. Hakulinen, L. Silakoski, J. Apajalahti, V. Backström, and E. L. Nurmiaho-Lassila. "Fluidized Bed Technology in the Anaerobic Treatment of Forest Industry Wastewaters." Water Science and Technology 17, no. 1 (January 1, 1985): 77–88. http://dx.doi.org/10.2166/wst.1985.0006.
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The reasons for studying anaerobic fluidised bed technology for the treatment of forest industry wastewaters are twofold: the very large volume enforcing hydraulic loading beyond the limits tolerated by conventional anaerobic techniques and the low nutrient need compared with aerobic methods. In this paper we describe the results obtained for four different pulp mill waste streams: sulfite bleaching and evaporator condensate wastewaters , wastewater from displacement bleaching of kraft pulp and from thermomechanical pulping. We found that all four could be purified anaerobically within a hydraulic detention time of ≤12h and with a treatment efficiency of 3 to 4 kg of CODCr removed m−3 d−1. 80 to 90% of the CODCr of the thermomechanical pulp mill wastewater and evaporator condensate could be removed during anaerobic treatment, yielding ≥0.5m3 of biogas kg−1 CODCr removed. The bleaching wastewaters needed aerobic post-treatment and yielded little or no biogas.
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Mino, T., H. Satoh, and T. Matsuo. "Metabolisms of Different Bacterial Populations in Enhanced Biological Phosphate Removal Processes." Water Science and Technology 29, no. 7 (April 1, 1994): 67–70. http://dx.doi.org/10.2166/wst.1994.0309.
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The characteristics of two major bacterial populations, phosphate accumulating organisms and “G bacterium”, in the anaerobic–aerobic biological phosphate removal process are discussed with an emphasis on their metabolic functions. It is theoretically indicated that the system of the oxidation-reduction balance in the cell enables the anaerobic uptake of organic substrates and that this system is essential for the microorganisms to survive in anaerobic–aerobic processes.
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Jobbágy, A., B. Literáthy, and G. Tardy. "Implementation of glycogen accumulating bacteria in treating nutrient-deficient wastewater." Water Science and Technology 46, no. 1-2 (July 1, 2002): 185–90. http://dx.doi.org/10.2166/wst.2002.0475.
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Activated sludge treatment of nutrient-deficient wastes may lead to severe slime formation and consequent biomass separation difficulties. The purpose of this paper has been to show that bioreactor arrangement essentially influences the manner of biological excess carbon removal. In a comparative lab-scale experiment two differently arranged activated sludge systems were operated simultaneously: an aerated CSTR with an aerobic selector and an aerated CSTR with an anaerobic selector. The seed derived from an anaerobic/aerobic activated sludge plant of a winery. The model wastewater contained wine, sugar and acetic acid as organic carbon sources and lacked nutrients regarding both N and P, similarly to the influent of the full-scale plant. During the 52 days of the experiment the SVI values of the fully aerated system increased up to 600–800 cm3 g−1 whereas those of the anaerobic/aerobic system remained below 250 cm3 g−1. The SVI values showed a strict correlation with the amount of extracellular polysaccharides. In the anaerobic/aerobic experimental system, the high (40% of MLSS) intracellular polysaccharide content of the seed could be maintained. Besides the analytical data, also the microscopic observations of the biomass structure referred to the presence of glycogen accumulating organisms in both the lab- and full-scale anaerobic/aerobic systems.
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Bjerre, H. Løkkegaard, T. Hvitved-Jacobsen, S. Schlegel, and B. Teichgräber. "Biological activity of biofilm and sediment in the Emscher River, Germany." Water Science and Technology 37, no. 1 (January 1, 1998): 9–16. http://dx.doi.org/10.2166/wst.1998.0003.
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Investigations were performed on biofilm and sediment from the river Emscher, Germany, presently acting as a large wastewater collector. Biofilm laboratory batch experiments were performed under aerobic and anaerobic conditions. The aerobic biofilm surface activity in terms of dissolved oxygen (DO) consumption was determined. Under anaerobic conditions the sulfide production was investigated. Laboratory biofilm experiments were compared with full scale studies performed under aerobic and anaerobic conditions to determine the total biofilm and sediment activity at selected reaches of the Emscher. The biofilm and sediment activity determined may be used for modelling of wastewater quality changes in the Emscher.
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Austermann-Haun, U., R. Lange, C. F. Seyfried, and K. H. Rosenwinkel. "Upgrading an anaerobic/aerobic wastewater treatment plant." Water Science and Technology 37, no. 9 (May 1, 1998): 243–50. http://dx.doi.org/10.2166/wst.1998.0363.
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The given example of an anaerobic/aerobic wastewater treatment plant ((WWTP) for a big German brewery shows that it is possible to reduce the discharged values to a very low level, much lower than the minimum requirements of Appendix 11 of the German General Wastewater Administration Rule, which applies to breweries. This means that the present state of technology has been updated. Tests on a semi-technical scale were carried out and found to be necessary to find the most suitable design for the wastewater treatment plant. Running the tests in the brewery, it became obvious that disinfectants had to be substituted until a stable COD elimination was achieved. Full-scale tests in the plant would not have been feasible. Numerous modifications were carried out in the brewery to reduce the amount of cleaning and disinfectant agents as well as the amount of AOX, EDTA, NTA and aluminium used. The following article presents the findings of the investigations about the ammonification of organic nitrogen, bulking sludge and substrates for denitrification. Furthermore it demonstrates the low operating costs of anaerobic pre-treatment, even in combination with an aerobic stage and filtration unit.
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Bartoszewski, K., and A. Bilyk. "Pond Treatment of Rettery Wastewaters." Water Science and Technology 19, no. 12 (December 1, 1987): 79–83. http://dx.doi.org/10.2166/wst.1987.0130.
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Rettery wastewaters were treated in anaerobic and aerobic ponds. Anaerobic treatment yielded efficiencies of BOD5 and COD removal as low as 20%. The treatment process conducted under aerobic conditions in aerated and stabilizing ponds arranged in series took from 18 to 20 days and gave efficiencies of BOD5 and COD removal amounting to 90%. The experimental results were interpreted by virtue of the Eckenfelder equation. Excess activated sludge was subjected to aerobic stabilization in a separate tank. A new technology was suggested for the existing obsolete industrial treatment plant.
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Bolzonella, D., L. Innocenti, and F. Cecchi. "Biological nutrient removal wastewater treatments and sewage sludge anaerobic mesophilic digestion performances." Water Science and Technology 46, no. 10 (November 1, 2002): 199–208. http://dx.doi.org/10.2166/wst.2002.0330.
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The paper deals with the performances of the mesophilic anaerobic digestion treatment of sewage sludge from a full scale BNR process without primary settling (nominally 300,000 PE). A relation between the activated sludge observed yields, Yobs, and the anaerobic digester performance was preliminarily found: for values of Yobs of 0.25 kgVSS/kgCOD the anaerobic digester specific gas production showed the best performances (0.22 m3/kgVSfed). This has to be confirmed with wider future studies. It was also shown the level of sludge pre-thickening to be reached for the self-sustaining warming of the digester also in wintertime. According to the energetic balance and to a comparison with an aerobic stabilisation process, it was pointed out as when a co-generation unit for heat and energy production was introduced about 3.4 kWh/PE y of energy were produced in the anaerobic digestion process. On the other hand, 4.3 kWh/PE y were spent if an aerobic stabilisation process was applied. The economic assessment, carried out on the basis of the energy balances, showed that the anaerobic digestion is always economically advantageous if compared to aerobic stabilisation processes, also for small WWTPs. According to the energetic evaluations an environmental balance was assessed, in terms of CO2 emissions. The difference between anaerobic and aerobic processes was about 5.3 kgCO2/PE y in favour of anaerobic processes application.
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Ji, Yu Kun, and Hong He. "Application of Anaerobic Fermentation Technology in Prevent and Control Pollution of Livestock and Poultry." Advanced Materials Research 850-851 (December 2013): 1176–79. http://dx.doi.org/10.4028/www.scientific.net/amr.850-851.1176.
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Analysis different kinds of anaerobic fermentation technology using in prevent and control of livestock and poultry. Comparing removal rate of COD, total Nitrogen, total Phosphorus of Mixed anaerobic fermentation technology (CSTR), upflow sludge bed reactor (USR) and simple anaerobic pool. Removal rate of CSTR and USR is obvious better than simple an aerobic pool, and removal rate is proportional to the pollutant concentration. Overall evaluations of investment, occupation of land and rate. Points out the problems exist in the using of anaerobic fermentation technology and put forward reasonable suggestions.
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Hafner, Sasha D., Johan T. Madsen, Johanna M. Pedersen, and Charlotte Rennuit. "Inter-stage thermophilic aerobic digestion may increase organic matter removal from wastewater sludge without decreasing biogas production." Water Science and Technology 77, no. 3 (November 20, 2017): 721–26. http://dx.doi.org/10.2166/wst.2017.590.
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Abstract Combining aerobic and anaerobic digestion in a two-stage system can improve the degradation of wastewater sludge over the use of either technology alone. But use of aerobic digestion as a pre-treatment before anaerobic digestion generally reduces methane production due to loss of substrate through oxidation. An inter-stage configuration may avoid this reduction in methane production. Here, we evaluated the use of thermophilic aerobic digestion (TAD) as an inter-stage treatment for wastewater sludge using laboratory-scale semi-continuous reactors. A single anaerobic digester was compared to an inter-stage system, where a thermophilic aerobic digester (55 °C) was used between two mesophilic anaerobic digesters (37 °C). Both systems had retention times of approximately 30 days, and the comparison was based on measurements made over 97 days. Results showed that the inter-stage system provided better sludge destruction (52% volatile solids (VS) removal vs. 40% for the single-stage system, 44% chemical oxygen demand (COD) removal vs. 34%) without a decrease in total biogas production (methane yield per g VS added was 0.22–0.24 L g−1 for both systems).
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Shrihari, S., and Vinod Tare. "Anaerobic-aerobic treatment of distillery wastes." Water, Air, and Soil Pollution 43, no. 1-2 (January 1989): 95–108. http://dx.doi.org/10.1007/bf00175586.
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Rantala, P., and P. Väänänen. "Cost Comparison of Aerobic and Anaerobic Wastewater Treatment Systems." Water Science and Technology 17, no. 1 (January 1, 1985): 255. http://dx.doi.org/10.2166/wst.1985.0020.
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The costs of different types of aerobic, anaerobic and combined wastewater treatment systems are compared in this study. The assumed BOD or COD-loads from typical forest industry processes form the basis of comparison. General cost curves for various waste treatment processes and some case examples are also presented. In the calculations it is assumed that the wastewater is treated to the same effluent quality by using activated sludge, modified activated sludge and combination of anaerobic-aerobic treatment process. In anaerobic-aerobic systems different types of combinations are analyzed. Investment, running and annual costs have been evaluated for each system. The study shows that selection of the method or combination of methods must always be made case by case. It has been found out that in some cases the anaerobic-aerobic process combination is economically competitive. Competitiveness will increase if biogas can be utilized and a moderate price could be calculated for it. In some cases activated sludge, and especially aerated lagoon processes, has a disadvantage of requiring larger treatment spaces. Poor soil conditions and long distances to lead effluent may significantly increase the cost of these aerobic treatment methods.
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Wett, B., M. Hell, G. Nyhuis, T. Puempel, I. Takacs, and S. Murthy. "Syntrophy of aerobic and anaerobic ammonia oxidisers." Water Science and Technology 61, no. 8 (April 1, 2010): 1915–22. http://dx.doi.org/10.2166/wst.2010.969.
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Deammonification is known as an efficient and resource saving sidestream process option to remove the nitrogen load from sludge liquors. The transfer of the intermediate product nitrite between both syntrophic groups of organisms – aerobic and anaerobic ammonia oxidizers (AOB) – appears very sensitive to process conditions such as temperature, dissolved oxygen (DO) and operating nitrite level. Growth kinetics for aerobic and anaerobic AOBs differ by one order of magnitude and require an adequate selection of sludge retention time. This paper provides measurement- and model-based results on how selected sludge wasting impacts population dynamics in a suspended growth deammonification system. Anammox enrichment up to a doubled portion in mixed liquor solids can substantially improve process stability in difficult conditions. A case-study on low temperature operations outlines two possible strategies to balance syntrophic consumption of ammonium and nitrite.
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Abeling, U., and C. F. Seyfried. "Anaerobic-Aerobic Treatment of Potato-Starch Wastewater." Water Science and Technology 28, no. 2 (July 1, 1993): 165–76. http://dx.doi.org/10.2166/wst.1993.0098.
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Production of potato starch produces wastewaters with high concentrations of COD, nitrogen and phosphorus. The best known and most economical solution for the nearly full elimination of these substances is the two-stage anaerobic-aerobic treatment. The anaerobic pretreatment must only go so far as to maintain enough COD for biological nitrogen and phosphorus elimination in the aerobic stage. To optimize this process, several tests have been carried out on nitrification/denitrification by means of the intermediate product nitrite. The carbon consumption amounts to only 60% in comparison with denitrification via nitrate. The essential parameter for regulating the process is the concentration of free ammonia in the reactor. Concentrations of 1 to 5mg NH3/l inhibit the nitratation but not the nitritation. A separation of both partial steps is possible. The content of ammonia was controlled by means of continuous NH4 and pH measuring. The process is suitable for many wastewaters with low COD/TKN ratios and high nitrogen concentrations. If there are undesired nitrite peaks in an aerobic treatment plant caused by high pH values and temperatures, specific nitrogen elimination by means of nitrite is a reliable treatment system.
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Nielsen, P. H., P. Roslev, T. E. Dueholm, and J. L. Nielsen. "Microthrix parvicella, a specialized lipid consumer in anaerobic–aerobic activated sludge plants." Water Science and Technology 46, no. 1-2 (July 1, 2002): 73–80. http://dx.doi.org/10.2166/wst.2002.0459.
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The in situ physiology of the filamentous bacterium Microthrix parvicella was investigated in anaerobic-aerobic dynamic phases in activated sludge with focus on the uptake of long chain fatty acids (LCFA) and growth. When 14C-labeled oleic acid was added to activated sludge with an excessive growth of M. parvicella, only little 14C-CO2 was produced under anaerobic conditions while a lot was produced under aerobic conditions. Microautoradiographic studies revealed that M. parvicella took up oleic acid under both anaerobic and aerobic conditions, while only a few floc formers were able to take it up under anaerobic conditions. Extraction and separation of the radioactive biomass into different lipid fractions showed that the oleic acid was stored mainly as neutral lipids under anaerobic conditions, whereas conversion to membrane phospholipids occurred almost exclusively under aerobic conditions, indicating growth. The surface properties of M. parvicella and other bacteria were characterized by hydrophobic fluorescent microspheres, which showed that M. parvicella was relatively hydrophobic. Furthermore, a surface-associated extracellular lipase activity was observed, indicating the ability of M. parvicella to degrade lipids near the filament surface. The results support the hypothesis that uptake and storage of LCFA as lipids under anaerobic conditions provide an effective competition strategy against bacteria that can only take up LCFA under aerobic conditions. Thus, M. parvicella seems to be a specialized lipid consumer with a physiological potential analogous to PAOs and GAOs being able to take up LCFA (but not short chain fatty acids or glucose) under anaerobic conditions and subsequently use the storage material for growth when nitrate or oxygen are available as electron acceptors.
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Harun, Hasnida, Aznah Nor Anuar, Zaini Ujang, Noor Hasyimah Rosman, and Inawati Othman. "Performance of aerobic granular sludge at variable circulation rate in anaerobic–aerobic conditions." Water Science and Technology 69, no. 11 (March 22, 2014): 2252–57. http://dx.doi.org/10.2166/wst.2014.156.
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Aerobic granular sludge (AGS) has been applied to treat a broad range of industrial and municipal wastewater. AGS can be developed in a sequencing batch reactor (SBR) with alternating anaerobic–aerobic conditions. To provide anaerobic conditions, the mixed liquor is allowed to circulate in the reactor without air supply. The circulation flow rate of mixed liquor in anaerobic condition is the most important parameter of operation in the anaerobic-AGS processes. Therefore, this study investigates the effect of circulation rate on the performance of the SBR with AGS. Two identical reactors namely R1 and R2 were operated using fermented soy sauce wastewater at circulation rate of 14.4 and 36.0 l/h, respectively. During the anaerobic conditions, the wastewater was pumped out from the upper part of the reactor and circulated back into the bottom of the reactor for 230 min. A compact and dense AGS was observed in both reactors with a similar diameter of 2.0 mm in average, although different circulation rates were adopted. The best reactor performance was achieved in R2 with chemical oxygen demand removal rate of 89%, 90% total phosphorus removal, 79% ammonia removal, 10.1 g/l of mixed liquor suspended solids and a sludge volume index of 25 ml/g.
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Melgoza, R. M., M. Chew, and G. Buitrón. "Start-up of a sequential anaerobic/aerobic batch reactor for the mineralization of p-nitrophenol." Water Science and Technology 42, no. 5-6 (September 1, 2000): 289–92. http://dx.doi.org/10.2166/wst.2000.0526.
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The start-up of a sequencing batch biofilter integrating anaerobic and aerobic conditions, for the mineralization of P-nitrophenol (PNP) was studied. In this study a reactor packed with volcanic stones and inoculated with microorganisms from activated sludge processes treating municipal and industrial wastewater was used. The reactor was acclimated with a concentration of PNP of 25 mg/l during 75 days (25 cycles). The duration of the first two operation cycles was 8 days. As the bacterial population acclimated to the anaerobic/aerobics conditions, cycles duration was reduced to 40 h (30 h anaerobic stage and 10 h aerobic one). The PNP was transformed to p-aminophenol (PAP) in the anaerobic phase. The mineralization of PAP was found in the oxidative phase. Removal efficiencies of 100% were obtained for initial concentrations of 25 and 55 mg/l of PNP. In the reductive phase (anaerobic) 60% of biotransformation of the PNP to PAP was observed. In the aerobic phase the amines mineralization was 100%.
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Häggblom, Max, and Mirja Salkinoja-Salonen. "Biodegradability of Chlorinated Organic Compounds in Pulp Bleaching Effluents." Water Science and Technology 24, no. 3-4 (August 1, 1991): 161–70. http://dx.doi.org/10.2166/wst.1991.0472.
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In this work the biodegradability of displacement bleaching effluents of kraft pulping was studied. A sequential treatment with an anaerobic fluidized bed and an aerobic trickling filter was effective in degrading the chlorinated high- and low-molecular-weight material. The treatment significantly reduced the COD, BOD and the organic chlorine (AOX) of the wastewater. COD and BOD reduction was greatest in the aerobic process whereas dechlorination was significant in the anaerobic process. Less than 3% of the COD removed was generated to sludge. With the combined aerobic and anaerobic treatment over 65% reduction of AOX and over 75% reduction of chlorinated phenolic compounds was observed. The COD/AOX-ratio of the wastewater was similar before and after treatment, indicating that the chlorinated material was as biodegradable as the nonchlorinated. Microbes capable of mineralizing pentachlorophenol constituted approximately 3% of the total heterotrophic microbial population in the aerobic trickling filter. Two aerobic polychlorophenol degrading Rhodococcus strains were able to degrade polychlorinated phenols, guaiacols and syringols in the bleaching effluent.
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Forgie, D. J. L. "Selection of the Most Appropriate Leachate Treatment Methods: Part 3: A Decision Model for the Treatment Train Selection." Water Quality Research Journal 23, no. 2 (May 1, 1988): 341–55. http://dx.doi.org/10.2166/wqrj.1988.024.
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Abstract This paper outlines development of a procedure for the selection of the most appropriate leachate treatment method(s) for a given leachate. The performance of aerobic biological, anaerobic biological and physical-chemical leachate treatment are discussed, based on the BOD5/COD ratio and the molecular weight of the organics in the leachate. An initial level of treatment selection screening, which is based on the BOD5/COD ratio, the molecular weight of the organics, and the volatile fatty acid (VFA), ammonia and metal concentrations is presented. Subsequent, separate decision models for anaerobic biological, aerobic biological and physical chemical treatment are also presented. It is shown that there is no one solution to leachate treatment but that a combination of anaerobic biological, aerobic biological and physical chemical treatment will be needed.
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Çiftçi, T., and I. Öztürk. "Nine years of full-scale anaerobic–aerobic treatment experiences with fermentation industry effluents." Water Science and Technology 32, no. 12 (December 1, 1995): 131–39. http://dx.doi.org/10.2166/wst.1995.0475.
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This paper presents the results of nine years of experience in design and operating of full-scale anaerobic-aerobic treatment plants in a fermentation industry producing baker's yeast from sugarbeet molasses. The PAKMAYA Izmit Factory has a large two-staged treatment plant since 1986: anaerobic first stage and aerobic second stage. The anaerobic reactors were constructed as Upflow Anaerobic Sludge Blanket Reactors (UASBR) with internal and external sludge recirculation facilities. Average COD removals remain in the range of 75% in the mesophilic anaerobic stage. Average daily biogas production rates are as high as 20,000 m3/day. This treatment plant is one of the largest in the world in terms of biogas production. Similar systems were constructed later in two other factories of the same company (Cumaova-Bolu, Kemalpasa-Izmir). The biogas conversion yield is about 0.65 m3 per kg COD removed. The energy produced from the biogas used in the boiler houses is about 35% of the total energy requirement of the factory. The effluents from the anaerobic first stage are fed to the subsequent aerobic treatment system by mixing with low strength effluents of the factory. The aerobic second stage was designed and operated as an extended aeration activated sludge system. The COD removals of the aerobic stage are averaging at about 60 to 75%. This paper also discusses the operating problems encountered in the various stages of the treatment system and their solutions during the nine years of full-scale operation in three different treatment plants of PAKMAYA.
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Sponza, D. T., and H. Atalay. "Simultaneous toxicity and nutrient removals in simulated DEPHANOX (anaerobic/anoxic/oxic sequentials) process treating dinitrotoluene and trichlorotoluene." Water Science and Technology 49, no. 5-6 (March 1, 2004): 237–44. http://dx.doi.org/10.2166/wst.2004.0759.
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A modified DEPHANOX process including two upflow sludge blanket reactors (USB) (anaerobic-upflow sludge blanket -UASB and anoxic-upflow anoxic sludge blanket -UANSB) and one completely stirred tank reactor (CSTR system was simulated in order to detect the simultaneous removal of dinitrotoulene (DNT), trichlorotoluene (TCT), and nutrients. The phosphorus uptake and nitrification was excessively determined in aerobic CSTR reactor. Influent DNT was transformed to toluene, NH4-N and total aromatic amines (TAA) while TCT was transformed to toluene and dichlorotoluene (DCT) under anaerobic and anoxic conditions. Increasing the volumetric loading rate of DNT and TCT from 18 mg/L.day and 0.35 g/L.day to 60 mg/l.day and 1.2 g/L.day, respectively, resulted in higher COD conversion (70-80%) rates and methane productions (250-300 ml/day) in anaerobic reactor. 90% NO3-N and 87% PO4-P were achieved in anoxic and aerobic reactors at DNT and TCT loading rates as high as 40-60 mg/L.day and 0.8-1.2 g/L.day, respectively. The TAA produced under anaerobic and anoxic conditions were ultimately removed under the aerobic stage. The UASB and anoxic UASB reactor effluents were less toxic relative to the influent when analyzed by anaerobic toxicity tests and specific methanogenic activity tests, indicating that such anaerobic/anoxic aerobic sequential treatments could be able to reduce toxic organics together with nutrient removal.
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Amaral, F. M., L. Florêncio, M. T. Kato, P. A. Santa-Cruz, and S. Gavazza. "Hydraulic retention time influence on azo dye and sulfate removal during the sequential anaerobic–aerobic treatment of real textile wastewater." Water Science and Technology 76, no. 12 (September 15, 2017): 3319–27. http://dx.doi.org/10.2166/wst.2017.378.
Full textAbstract:
Abstract In the present study, we evaluate the behavior of real textile wastewater treatment using a system composed of two sequential pilot-scale reactors (anaerobic followed by aerobic) during 622 days. The work focused on the competition between color and sulfate removal processes, when the hydraulic retention time (HRT) was increased in the anaerobic/aerobic reactors from 16/12 hours in phase I (PI) to 4/3 days in phase II (PII). The organic matter was successfully removed in both phases through the system, and the highest efficiency (75%) was achieved in PII. The increase in the HRT did not improve azo dye degradation under anaerobic conditions. Instead, it favored sulfate reduction, which removal efficiency increased from 26% in PI to 75% in PII. Aromatic amines were detected in the anaerobic reactor effluent and removed in the aerobic reactor.
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Driessen, W. J. B. M., and C. O. Wasenius. "Combined Anaerobic/Aerobic Treatment of Peroxide Bleached TMP Mill Effluent." Water Science and Technology 29, no. 5-6 (March 1, 1994): 381–89. http://dx.doi.org/10.2166/wst.1994.0731.
Full textAbstract:
In this paper combined anaerobic/aerobic treatment is illustrated by two examples at integrated pulp and paper mills with peroxide bleached TMP pulp production. The concept of combined biological treatment is to treat the more polluted effluents from the TMP pulp mill in an anaerobic reactor and subsequently to mix them with the less concentrated effluent, for treatment by an aerobic process. Extensive pilot research was done to confirm the feasibility of anaerobic treatment of peroxide bleached TMP mill effluent COD removal efficiencies of 55-60% were achieved at volumetric loading rates of up to 20 kg/m3/d. Possible toxic effects from peroxide could easily be neutralized by removal in a preacidification tank. Long term full scale experience proved that combined anaerobic aerobic treatment is an attractive and reliable method for treatment of peroxide bleached TMP mill effluent.