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49 ANAEROBIC GRANULES DEVELOPED FOR REDUCTIVE DECHLORINATION OF CHLOROPHENOLS AND CHLORINATED ETHYLENE Wei-Min Wu, Engineer Jeffrey Nye, Scientist Robert F. Hickey, Senior Engineer Lakshmi Bhatnagar, Senior Scientist Michigan Biotechnology Institute Lansing, Michigan 48909 INTRODUCTION Anaerobic processes have been developed for the treatment of organic wastes and wastewaters for many years. It has also been demonstrated that anaerobic bacteria can perform reductive dechlorination of toxic chlorinated organic compounds including polychlorinated biphenyls (PCBs), tetrachlo- roethylene (PCE) and chlorinated benzenes.1,6 These compounds are aerobically recalcitrant but can be reductively dechlorinated to less chlorinated compounds, allowing for further mineralization to C02 by aerobic organisms. In addition, some chlorinated aromatic compounds such as chlorophenols and chlorobenzoates can be mineralized to CH4 and C02 under anaerobic conditions. Anaerobic granules are self-immobilized microbial consortia which form a matrix structure with diameters ranging from 0.1 to 5.0 mm. This granular structure helps protect the anaerobic bacteria from unfavorable environmental conditions such as changes in pH and exposure to oxygen. It also provides favorable conditions for syntrophic metabolism of substrates and cogrowth of different microbial species. Anaerobic granules have a much higher cell-density than suspended-growth cultures and, therefore, have a high metabolic activity per unit volume. The prevalent organisms in granules are, generally, methanogens, syntrophic acetogens, and hydrolytic-fermentative bacteria.2 Sulfate-reducing bacteria may also be present.3 The anaerobic granules developed on organic wastewaters which do not contain chlorinated organic compounds normally do not have significant dechlorinating activity. However, anaerobic granules with special dechlorinating activities can be developed by using microbial consortia which are able to form granular structure together with additional dechlorinating organisms. Anaerobic granular sludges have been developed for the treatment of various chlorinated compounds including pentachlorophenol (PCP), PCE and PCBs at Michigan Biotechnology Institute. In this communication, we will describe the performance of anaerobic granules developed for the dechlorination of PCP and PCE. BACKGROUND Reductive Dechlorination and Mineralization of PCP Pentachlorophenol (PCP) is a biocide that was widely used in the United States, mainly for the preservation of wood and wood products. Along with other chlorophenols, PCP has been listed as a priority pollutant by the U.S. Environmental Protection Agency.4 PCP can be completely mineralized to methane and C02 by anaerobic microorganisms.5 Sequential reductive dechlorination of PCP occurs prior to complete mineralization in digested sludges, sediments and soils.1,5"12 Phenol can be further degraded to methane and C02 by anaerobic organisms. The metabolic pathways of reductive dechlorination of PCP were identified by several individual batch experiments and yielded a complex pathway based on intermediate chlorophenols observed.5,6,11"14 The sequential dechlorination of PCP could take place at any position, i.e., ortho, meta or para, and result in formation of various chlorophenols with a lesser number of chlorine substituents. Eventually, these intermediate chlorophenols could be completely dechlorinated to phenol and subsequently mineralized to CH4 and 48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in U.S.A.
Object Description
Purdue Identification Number | ETRIWC199349 |
Title | Anaerobic granules developed for reductive dechlorination of chlorophenols and chlorinated ethylene |
Author |
Wu, Wei-Min Nye, Jeffrey Hickey, Robert F. Bhatnagar, Lakshmi |
Date of Original | 1993 |
Conference Title | Proceedings of the 48th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,21159 |
Extent of Original | p. 483-494 |
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 | 2009-11-10 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 483 |
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 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | 49 ANAEROBIC GRANULES DEVELOPED FOR REDUCTIVE DECHLORINATION OF CHLOROPHENOLS AND CHLORINATED ETHYLENE Wei-Min Wu, Engineer Jeffrey Nye, Scientist Robert F. Hickey, Senior Engineer Lakshmi Bhatnagar, Senior Scientist Michigan Biotechnology Institute Lansing, Michigan 48909 INTRODUCTION Anaerobic processes have been developed for the treatment of organic wastes and wastewaters for many years. It has also been demonstrated that anaerobic bacteria can perform reductive dechlorination of toxic chlorinated organic compounds including polychlorinated biphenyls (PCBs), tetrachlo- roethylene (PCE) and chlorinated benzenes.1,6 These compounds are aerobically recalcitrant but can be reductively dechlorinated to less chlorinated compounds, allowing for further mineralization to C02 by aerobic organisms. In addition, some chlorinated aromatic compounds such as chlorophenols and chlorobenzoates can be mineralized to CH4 and C02 under anaerobic conditions. Anaerobic granules are self-immobilized microbial consortia which form a matrix structure with diameters ranging from 0.1 to 5.0 mm. This granular structure helps protect the anaerobic bacteria from unfavorable environmental conditions such as changes in pH and exposure to oxygen. It also provides favorable conditions for syntrophic metabolism of substrates and cogrowth of different microbial species. Anaerobic granules have a much higher cell-density than suspended-growth cultures and, therefore, have a high metabolic activity per unit volume. The prevalent organisms in granules are, generally, methanogens, syntrophic acetogens, and hydrolytic-fermentative bacteria.2 Sulfate-reducing bacteria may also be present.3 The anaerobic granules developed on organic wastewaters which do not contain chlorinated organic compounds normally do not have significant dechlorinating activity. However, anaerobic granules with special dechlorinating activities can be developed by using microbial consortia which are able to form granular structure together with additional dechlorinating organisms. Anaerobic granular sludges have been developed for the treatment of various chlorinated compounds including pentachlorophenol (PCP), PCE and PCBs at Michigan Biotechnology Institute. In this communication, we will describe the performance of anaerobic granules developed for the dechlorination of PCP and PCE. BACKGROUND Reductive Dechlorination and Mineralization of PCP Pentachlorophenol (PCP) is a biocide that was widely used in the United States, mainly for the preservation of wood and wood products. Along with other chlorophenols, PCP has been listed as a priority pollutant by the U.S. Environmental Protection Agency.4 PCP can be completely mineralized to methane and C02 by anaerobic microorganisms.5 Sequential reductive dechlorination of PCP occurs prior to complete mineralization in digested sludges, sediments and soils.1,5"12 Phenol can be further degraded to methane and C02 by anaerobic organisms. The metabolic pathways of reductive dechlorination of PCP were identified by several individual batch experiments and yielded a complex pathway based on intermediate chlorophenols observed.5,6,11"14 The sequential dechlorination of PCP could take place at any position, i.e., ortho, meta or para, and result in formation of various chlorophenols with a lesser number of chlorine substituents. Eventually, these intermediate chlorophenols could be completely dechlorinated to phenol and subsequently mineralized to CH4 and 48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in U.S.A. |
Resolution | 300 ppi |
Color Depth | 8 bit |
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