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42 FEASIBILITY OF SYNCHRONOUS AEROBIC/ANAEROBIC PROCESSES WITH A SINGLE UPFLOW SLUDGE BED SYSTEM C.F. Shen, Research Associate D. Rousselle, Summer Student S.R. Guiot, Project Leader Biotechnology Research Institute National Research Council Canada Montreal, Quebec, Canada, H4P 2R2 INTRODUCTION Many xenobiotic compounds which are refractory under aerobic conditions' seem to be readily biotranstormed anaerobically. In turn, partially degraded products which resist further anaerobic degradation can be completely mineralized by aerobic microorganisms.2 These facts point out the limitation and complementary aspects of aerobic and anaerobic treatments, and suggest thar compounds degrading through a series of reductive and oxidative steps may be most efficiently biodegraded by sequential anaerobic-aerobic processes in which anaerobic digestion is a primary treatment to furnish partially or completely degraded compounds for aerobic polishing.3 In an anaerobic-aerobic sequence system, the anaerobic and aerobic bacteria function in separate units that complement each other. The economical scheme of operating full-scale anaerobic-aerobic systems is to construct engineered microecosystems integrating oxic and anaerobic niches and creating synergism between oxidation and reductive catabolisms. The co-existence of anaerobes and aerobes in oxic4 and anaerobic5 environments indicates the possibility of constructing micro- ecosystems in which both anaerobes and aerobes are able to survive. Under 02-limited conditions, aerobic respiring microorganisms can maintain very low dissolved oxygen concentrations in the aerobic/anaerobic co-cultured system, and the complete inhibition of anaerobes is avoided. Even in the aerobic process, the oxygen consumption of the aerobic bacteria on the periphery of immobilized biofilm can result in a built-up of an oxygen gradient,1 leaving the inner layer of biofilm free of oxygen and preventing the toxicity of 62. Anaerobic granular sludge is an appropriate matrix for the development of the above microecosystems including oxic and anaerobic niches.6 The facultative bacteria on the periphery, which create an abrupt oxygen gradient in the sludge, could prevent 02-toxicity to the 02-sensitive Methanoseata-\ike methanogens located in the core of the sludge.7 Obligatory anaerobic bacteria in the granular sludge have demonstrated their surviving abilities when exposed to certain 02-limited conditions.6-8-9 Aerobic/anaerobic coupled bioprocess seems to have great potential in the complete biodegradation of a broad range of recalcitrant toxic compounds. However, much work remains to be done before the aerobic/anaerobic coupled systems are employed to their full-scale application. The knowledge of bacterial behavior in an aerobic/anaerobic coupled reactor is lacking; the operation and design of aerobic/anaerobic coupled bioreactors are still at a preliminary stage. An understanding of the influence of process parameters, especially dissolved 02 concentration, on the reactor performance and bacterial behavior will enable us to optimize the operating conditions and improve the reactor design. 50th Purdue Industrial Waste Conference Proceedings, 1995. Ann Arbor Press, Inc., Chelsea. Michigan 48118. Printed in U.S.A. 385
Object Description
Purdue Identification Number | ETRIWC199542 |
Title | Feasibility of synchronous aerobic/anaerobic processes with a single upflow sludge bed system |
Author |
Shen, C. F. Rouselle, D. Guiot, S. R. |
Date of Original | 1995 |
Conference Title | Proceedings of the 50th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,45474 |
Extent of Original | p. 385-394 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-11-24 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 385 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | 42 FEASIBILITY OF SYNCHRONOUS AEROBIC/ANAEROBIC PROCESSES WITH A SINGLE UPFLOW SLUDGE BED SYSTEM C.F. Shen, Research Associate D. Rousselle, Summer Student S.R. Guiot, Project Leader Biotechnology Research Institute National Research Council Canada Montreal, Quebec, Canada, H4P 2R2 INTRODUCTION Many xenobiotic compounds which are refractory under aerobic conditions' seem to be readily biotranstormed anaerobically. In turn, partially degraded products which resist further anaerobic degradation can be completely mineralized by aerobic microorganisms.2 These facts point out the limitation and complementary aspects of aerobic and anaerobic treatments, and suggest thar compounds degrading through a series of reductive and oxidative steps may be most efficiently biodegraded by sequential anaerobic-aerobic processes in which anaerobic digestion is a primary treatment to furnish partially or completely degraded compounds for aerobic polishing.3 In an anaerobic-aerobic sequence system, the anaerobic and aerobic bacteria function in separate units that complement each other. The economical scheme of operating full-scale anaerobic-aerobic systems is to construct engineered microecosystems integrating oxic and anaerobic niches and creating synergism between oxidation and reductive catabolisms. The co-existence of anaerobes and aerobes in oxic4 and anaerobic5 environments indicates the possibility of constructing micro- ecosystems in which both anaerobes and aerobes are able to survive. Under 02-limited conditions, aerobic respiring microorganisms can maintain very low dissolved oxygen concentrations in the aerobic/anaerobic co-cultured system, and the complete inhibition of anaerobes is avoided. Even in the aerobic process, the oxygen consumption of the aerobic bacteria on the periphery of immobilized biofilm can result in a built-up of an oxygen gradient,1 leaving the inner layer of biofilm free of oxygen and preventing the toxicity of 62. Anaerobic granular sludge is an appropriate matrix for the development of the above microecosystems including oxic and anaerobic niches.6 The facultative bacteria on the periphery, which create an abrupt oxygen gradient in the sludge, could prevent 02-toxicity to the 02-sensitive Methanoseata-\ike methanogens located in the core of the sludge.7 Obligatory anaerobic bacteria in the granular sludge have demonstrated their surviving abilities when exposed to certain 02-limited conditions.6-8-9 Aerobic/anaerobic coupled bioprocess seems to have great potential in the complete biodegradation of a broad range of recalcitrant toxic compounds. However, much work remains to be done before the aerobic/anaerobic coupled systems are employed to their full-scale application. The knowledge of bacterial behavior in an aerobic/anaerobic coupled reactor is lacking; the operation and design of aerobic/anaerobic coupled bioreactors are still at a preliminary stage. An understanding of the influence of process parameters, especially dissolved 02 concentration, on the reactor performance and bacterial behavior will enable us to optimize the operating conditions and improve the reactor design. 50th Purdue Industrial Waste Conference Proceedings, 1995. Ann Arbor Press, Inc., Chelsea. Michigan 48118. Printed in U.S.A. 385 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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