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Biofilms and their importance to contactor design
Abstracts
251
SECTION 4 PRACTICAL USE OF NEW BIOREMEDIATION TECHNOLOGIES
Biofilms and their Importance to Contactor Design H. Eccles and M. Wright Company Research Laboratory, British Nuclear Fuels plc, Springfi’elds, Preston, Lancashire, PR4 OXJ. UK In nature and environmental technology. the most frequently encountered physiological form adopted by microbial populations is an immobilized state, generally a biofilm. rather than as suspensions of free cells, Although such biolilms affect virtually every aspect of engineering and biotechnology, their interaction with metals is not well understood. Consequently, bioreactors employed for the removal of pollutants in particular metal ions in general are generously over-designed. This paper considers the key issues in the design of bioreactors for metal removal which are based on sulphate reducing bacteria. The role of extracellular polymers and how these can markedly influence biofilm physiology and behaviour will be described. Their ion exchange capability for metals and how this assists or hinders the design of bioreactors will be explored. The need for experimental studies which generate more precise and translatable fundamental data which can be readily incorporated into design criteria will be discussed.
Biodegradation
of PCBs in Ground Water
K. Demnerovi”, F. Ka%nek*, J. Burkhard’, J. Pazlarovi” and M. Mackovi” “Department of’ Biochemistty~ and Microbiology, Faculty of Food and Biochem. Technology ICT Prague, Technicka 3, 16628 Prague 6, Czech Republic, hDepartment of Environmental Chemistry, Faculty qf’ Water Treatment and Environmental Technology, ICT Prague, Technicka 5. 166 28 Prague6. Czech Republic, and “The Institute qf Chemical Process Fundamentals, Czech Academy of‘ Sciences. Roxojovci 135, 16501 Prague 6. Czech Republic The two-step technology for removing PCBs from contaminated ground water was developed. The first step includes sorption of PCBs on the sorbent (Bentonite activated by Fe ions and carbon fibers) and the second step is represented by biodegradation of sorbed PCBs. The indigenous bacteria isolated from the polluted area were used for the biodegradation. Seed bacteria were cultivated in a simple mineral medium with biphenyl as the only carbon source. The experiments were run in the laboratory and on site under semi-pilot scale and pilot scale conditions. In the presented contribution the characterization of both cocultures and isolated strains and the comparison of the efficiency of designed technology under different scales will be given.
Bioremediation of CKW- and BTEX-Contaminated Soil by In-situ Infiltration in Combination with On-Site Water and Air Treatment in a Pilot Plant 0. Meyer”, J. Warrelmannb and H. von Reis’ “Lehrstuhl fur Mikrobiologie, Universitat Bavreuth, 95440 Bavreuth, Germany, hUmweltschutz Nord GmbH and Co., Abtl. TLM, Industriepark 6, 27777 Ganderkesee, Germany, and “big.-Btiro R. W. Ashauer and Partner GmbH, TtirnichIndustriegebiet I, Postfach 4128, Kerpen. Germany The site at Eppelheim is an abandoned gravel pit area with perchloroethylene and BTEX-aromatics as the main contaminants [Meyer et al. (1992). Microb. Releases Ill. The contaminants were leached from the soil by applying a horizontal water flow of up to 1 m3/h through injection and elution wells covering small distances of about 1Sm. For safety reasons the entire infiltration process was established in 2.5 by 10m steel columns vibrated into the dump and sealed against the environment. The effluent water was adjusted for contaminant concentrations, pH and temperature. It was amended with 0.03% of sucrose to establish anaerobic conditions and to serve as a (co)substrate for the degrading microflora. Then the water was pumped onto a series of solid bed bioreactors (14.4m3 each) with a flow of up to IOm’/h. The reactors were operated under denitrifying methanogenic and aerobic methanotrophic conditions. Several filter stages, including final charcoal filtration. were also provided. Contaminants in the process air (about 700 m”/h) were treated in a series of two Aeroferm-biofilter units (6.5 x 2.4 x 3.2m) supplied with a pH-buffered filter bed (11 m’) composed of humus. We report here on the performance and the microbiology of the pilot plant bioremediation process.
Biotransformation of Polychlorinated Soil by Addition of Terpenes
Biphenyls in
B. Hernandez”, S.-C. Koh”, M. Chial’ and D. D. Focht” “Department qf Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA, and hDepartment of Microbiology, University qf Panuma. Panama Soils spiked with Aroclor 1242 were amended with the following plant terpenes: orange peels, ivy leaves, eucalyptus leaves and pine needles. Complete biotransformation of Aroclor 1242 and higher numbers of biphenyl-utilizing bacteria occurred in all amended soils in comparison to the control soils after six months. Nine strains of coryneform bacteria isolated from the amended soils grew on the major terpenes found in the plant residues. A probe of the bphA gene, which encodes for the dioxygenation of biphenyl/ polychlorinated biphenyl ring hybridized to the DNA of all
251
SECTION 4 PRACTICAL USE OF NEW BIOREMEDIATION TECHNOLOGIES
Biofilms and their Importance to Contactor Design H. Eccles and M. Wright Company Research Laboratory, British Nuclear Fuels plc, Springfi’elds, Preston, Lancashire, PR4 OXJ. UK In nature and environmental technology. the most frequently encountered physiological form adopted by microbial populations is an immobilized state, generally a biofilm. rather than as suspensions of free cells, Although such biolilms affect virtually every aspect of engineering and biotechnology, their interaction with metals is not well understood. Consequently, bioreactors employed for the removal of pollutants in particular metal ions in general are generously over-designed. This paper considers the key issues in the design of bioreactors for metal removal which are based on sulphate reducing bacteria. The role of extracellular polymers and how these can markedly influence biofilm physiology and behaviour will be described. Their ion exchange capability for metals and how this assists or hinders the design of bioreactors will be explored. The need for experimental studies which generate more precise and translatable fundamental data which can be readily incorporated into design criteria will be discussed.
Biodegradation
of PCBs in Ground Water
K. Demnerovi”, F. Ka%nek*, J. Burkhard’, J. Pazlarovi” and M. Mackovi” “Department of’ Biochemistty~ and Microbiology, Faculty of Food and Biochem. Technology ICT Prague, Technicka 3, 16628 Prague 6, Czech Republic, hDepartment of Environmental Chemistry, Faculty qf’ Water Treatment and Environmental Technology, ICT Prague, Technicka 5. 166 28 Prague6. Czech Republic, and “The Institute qf Chemical Process Fundamentals, Czech Academy of‘ Sciences. Roxojovci 135, 16501 Prague 6. Czech Republic The two-step technology for removing PCBs from contaminated ground water was developed. The first step includes sorption of PCBs on the sorbent (Bentonite activated by Fe ions and carbon fibers) and the second step is represented by biodegradation of sorbed PCBs. The indigenous bacteria isolated from the polluted area were used for the biodegradation. Seed bacteria were cultivated in a simple mineral medium with biphenyl as the only carbon source. The experiments were run in the laboratory and on site under semi-pilot scale and pilot scale conditions. In the presented contribution the characterization of both cocultures and isolated strains and the comparison of the efficiency of designed technology under different scales will be given.
Bioremediation of CKW- and BTEX-Contaminated Soil by In-situ Infiltration in Combination with On-Site Water and Air Treatment in a Pilot Plant 0. Meyer”, J. Warrelmannb and H. von Reis’ “Lehrstuhl fur Mikrobiologie, Universitat Bavreuth, 95440 Bavreuth, Germany, hUmweltschutz Nord GmbH and Co., Abtl. TLM, Industriepark 6, 27777 Ganderkesee, Germany, and “big.-Btiro R. W. Ashauer and Partner GmbH, TtirnichIndustriegebiet I, Postfach 4128, Kerpen. Germany The site at Eppelheim is an abandoned gravel pit area with perchloroethylene and BTEX-aromatics as the main contaminants [Meyer et al. (1992). Microb. Releases Ill. The contaminants were leached from the soil by applying a horizontal water flow of up to 1 m3/h through injection and elution wells covering small distances of about 1Sm. For safety reasons the entire infiltration process was established in 2.5 by 10m steel columns vibrated into the dump and sealed against the environment. The effluent water was adjusted for contaminant concentrations, pH and temperature. It was amended with 0.03% of sucrose to establish anaerobic conditions and to serve as a (co)substrate for the degrading microflora. Then the water was pumped onto a series of solid bed bioreactors (14.4m3 each) with a flow of up to IOm’/h. The reactors were operated under denitrifying methanogenic and aerobic methanotrophic conditions. Several filter stages, including final charcoal filtration. were also provided. Contaminants in the process air (about 700 m”/h) were treated in a series of two Aeroferm-biofilter units (6.5 x 2.4 x 3.2m) supplied with a pH-buffered filter bed (11 m’) composed of humus. We report here on the performance and the microbiology of the pilot plant bioremediation process.
Biotransformation of Polychlorinated Soil by Addition of Terpenes
Biphenyls in
B. Hernandez”, S.-C. Koh”, M. Chial’ and D. D. Focht” “Department qf Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA, and hDepartment of Microbiology, University qf Panuma. Panama Soils spiked with Aroclor 1242 were amended with the following plant terpenes: orange peels, ivy leaves, eucalyptus leaves and pine needles. Complete biotransformation of Aroclor 1242 and higher numbers of biphenyl-utilizing bacteria occurred in all amended soils in comparison to the control soils after six months. Nine strains of coryneform bacteria isolated from the amended soils grew on the major terpenes found in the plant residues. A probe of the bphA gene, which encodes for the dioxygenation of biphenyl/ polychlorinated biphenyl ring hybridized to the DNA of all