Combined Anaerobic/Aerobic Secondary Municipal Wastewater Treatment: Pilot-Plant Demonstration of the UASB/Aerobic Solids Contact System
Publication: Journal of Environmental Engineering
Volume 133, Issue 4
Abstract
Anaerobic pretreatment followed by aerobic posttreatment of municipal wastewater is being used more frequently. Recent investigations in this field using an anaerobic fluidized bed reactor/aerobic solids contact combination demonstrated the technical feasibility of this process. The investigation presented herein describes the use of a combined upflow anaerobic sludge bed (UASB)/aerobic solids contact system for the treatment of municipal wastewater and attempts to demonstrate the technical feasibility of using the UASB process as both a pretreatment unit and a waste activated sludge digestion system. The results indicate that the UASB reactor has a total chemical oxygen demand removal efficiency of 34%, and a total suspended solids removal efficiency of about 36%. Of the solids removed by the unit, 33% were degraded by the action of microorganisms, and 4.6% accumulated in the reactor. This low solids accumulation rate allowed operating the UASB reactor for three months without sludge wasting. The long solids retention time in this unit is comparable to the one normally used in conventional sludge digestion units, thus allowing the stabilization of the waste activated sludge returned to the UASB reactor. Particle flocculation was very poor in the UASB reactor, and therefore, it required postaeration periods of at least to proceed successfully in the aerobic unit. Polymer generation, which is necessary for efficient biological flocculation, was practically nonexistent in the anaerobic unit; therefore, it was necessary to maintain dissolved oxygen levels greater than in the aerobic solids contact chamber for polymer generation to proceed at optimum levels. Once these conditions were attained, the quality of the settled solids contact chamber effluent always met the BOD/L, SS/L secondary effluent guidelines.
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Acknowledgments
Financial support for the research reported herein was provided by the University of New Orleans Schlieder Urban Environmental Systems Center through a grant from the U.S. Environmental Protection Agency, and by the Jefferson Parish Department of Sewerage.
References
Alem Sobrinho, P., Silva, S. M. C. P., and Garcia, A. D., Jr. (1995). “Avaliaçao do Sistema Reator UASB e processo de lodos ativados para tratamento de esgotos sanitarios com elevada parcela de contribuiçao industrial.” Anais: 18th Congreso Brasileiro de Engenharia Sanitaria e Ambiental, Salvador, Bahia, set/95 (in Portuguese).
American Public Health Association (APHA). (1999). Standard methods for the examination of waster and wastewater. 20th Ed., Washington, D.C.
Bustillos, A. (2002). “Combined anaerobic/aerobic treatment for municipal wastewater.” Master’s thesis, Univ. of New Orleans, New Orleans.
Corzo, P. (2001). “Flocculation of anaerobic fluidized bed reactor effluent.” Master’s thesis, Univ. of New Orleans, New Orleans.
de Sousa, J. T., and Foresti, E. (1996). “Domestic sewage treatment in an upflow anaerobic sludge blanket-sequencing batch reactors system.” Water Sci. Technol., 33(3), 73–84.
Field, J. (2003). “Anaerobic granular sludge bed technology pages.” ⟨http://www.uasb.org/discover/agsb.htm⟩.
Franklin, R. J. (2001). “Full scale experience with anaerobic treatment of industrial wastewater.” Water Sci. Technol., 44(8), 1–6.
Goncalves, R. F., Veronez, F. A., Kissling, C. M. S., and Cassini, S. T. (1999). “Using a UASB reactor for thickening and digestion of discharged sludge from submerged aerated biofilter.” Water Sci. Technol., 45(10), 299–304.
Jenicek, P., Dohanyos, M., and Zabranska, J. (1999). “Combined anaerobic treatment of wastewaters and sludges.” Water Sci. Technol., 40(1), 85–91.
La Motta, E., Jimenez, J., Josse, J., and Manrique, A. (2004). “Role of bioflocculation on chemical oxygen demand removal in solids contact chamber of trickling filter/solids contact process.” J. Environ. Eng., 130(7), 726–735.
Lettinga, G., Van Velsen, S., Horma, S., De Zeeuw, W., and Klapwijk, A. (1980). “Use of the upflow sludge blanket (USB) reactor concept for biological wastewater treatment, especially for anaerobic treatment.” Biotechnol. Bioeng., 22(4), 699–734.
Luque, J. (2005). “Exocellular polymeric substances, bioflocculation, and sludge settling properties in a combined anaerobic/activated sludge process.” Ph.D. dissertation, Univ. of New Orleans, New Orleans.
Metcalf and Eddy. (2003) Wastewater engineering. Treatment, disposal, and reuse, 3rd Ed., McGraw-Hill, New York.
Pontes, P., Chernicharo, C., Frade, E., and Porto, M. (2003). “Performance evaluation of a UASB reactor used for combined treatment of domestic sewage and excess aerobic sludge from a trickling filter.” Water Sci. Technol., 48(6), 227–234.
Van Haandel, A., and Lettinga, G. (1994), Anaerobic sewage treatment, a practical guide for regions with hot climate, Wiley, New York.
Vieira, M., and Sonia, M. (1987), “Anaerobic treatment of domestic sewage in Brazil—Research results and full-scale experience.” CETESB, 185–196.
Yoda, M., Hattori, M., and Miyaji, Y. (1985). “Treatment of municipal wastewater by anaerobic fluidized bed: Behaviour of organic suspended solids in anaerobic reactor.” Proc., Seminary/Workshop: Anaerobic Treatment of Sewage, Univ. of Massachusetts, Amherst, Mass., 161–196.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 133 • Issue 4 • April 2007
Pages: 397 - 403
Copyright
© 2007 ASCE.
History
Received: Jun 24, 2005
Accepted: Aug 28, 2006
Published online: Apr 1, 2007
Published in print: Apr 2007
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