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Toxicity effects on anaerobic biodegradation: a case study
120
Abstracts
Biodegradation of Petroleum in “Piletas” in the v--A_ In..-L-1 la-L--,,~EPTCII III LWlUitl l-2Wl~UlUii O.H. Pucci, M. Bak and S.R. Peressutti C.E.I.M.A. Universidad National de La Patagonia San Juan Bosco, Comodoro Rivadaia, Argentina
In petroleum exploration, from the perforation of the well to the procedures of repair and maintenance, a great quantity of oily wastes and petroleum residues is produced. Over many years, these have been buried in holes next to the well, called “piletas”. These holes were not rendered impermeable, the only requirement being that they are enclosed. In Central Patagonia, Argentina, oil exploration activities have been intense since the beginning of the century and these “piletas” have been subjected to increasing criticism in the last few years because of.the damage being done to the environment and m.n~r;~ll,r h;rdc the ~~yvv’u”, tn L” m;avot;nn ““~‘U”“~ “II.&“. Tn 1111001 ‘/Id, l&l” Pc=rr.darv “““~CY’J fnt I”. Fn~rov Y..V’bJ
laid down a timescale for the elimination by the oil companies of these “piletas” of high risk. This has resulted in various companies proposing the use of their own bacterial strains for the elimination of the offending oils. The present report is a study of the processes which occur in these “piletas” and the behaviour of the inoculated bacteria.
Biodegradation of Organochlorine Compounds A. Neilsen IVL, Stockholm, Sweden
Organochlorine compounds have attracted interest since the discovery of chloroform as an anaesthetic, chloral hydrate as a sedative and more recently DDT as an insecticide. The value of - ?many industriai products such as PCBs depends on their chemicai stability, and many compounds including agrochemicals contain chlorine. In addition, a large and structurally diverse group of organochlorine compounds is produced by a range of biota, while some are by-products from the bleaching of pulp by conventional procedures using molecular chlorine. The chemical stability of organochlorine compounds is reflected in their resistance to microbial degradation, and this fact coupled to their ubiquitous occurrence in environmental samples has aroused widespread concern. The mechanisms of microbial degradation of aliphatic and aromatic organochlorine compounds include hydrolytic, oxidative, reductive and elimination mechanisms. These will be reviewed with reference to their limitations, the range of structures that have been studied, and attention drawn to the environmental consequences of biotransformation. Illustrative examples will be drawn from studies with chloroalkanes, and a range of aromatic compounds including hydrocarbons, carboxylic acids, phenols and anilines. Attention will be directed to important environmental constraints including anaerobic conditions and bioavailability, and brief mention will be made of the degradation of organofluorine and organobromine compounds to highlight the differences from organochlorine compounds.
tion was instituted which obliged chemical industries to have their standard laboratory measurements done in Brazilian laboratories. Nowadays, most of the pesticides registered in Brazil have their degradation studies developed under appropriate soil and climatic conditions.
Toxicity Effects on Anaerobic Biodegradation:
Case Study D.R. Paula Jr” and E. Forestb “University of Campinas, Agricultural Engineering School, Carnpinas, SP, and bUniversity of Sdo Paulo, Engineering School of S&o Carlos, Brazil
Sulfide toxicity studies were carried out using a lab-scale (10.5 1) UASB reactor operated continuously during 12 months under progressive increase of influent Na$ concentrations. NazS was directiy added to the synthetic substrate jbased on giucose and nutrient solution) in the feeding tank to obtain the desirable influent sulfide concentrations ranging from 10 to 500 mg/l. The influent COD concentration of 2000 mg/l and the hydraulic retention time of 15.6 h were maintained constant during the experiment. Stimulation effects were detected up to the sulfide concentration of 100 mg/l. Toxicity effects arose for sulfide concentrations beyond that value with gradual efficiency reduction (from 98 to 70% COD removal) to 500 mg/l of sulfide.
Treatment of Liquid Residues of the Citrus Fruit Industry by Photosynthetic Bacteria Rhodopseudomonas acidophila and R. palustris P.M. Lacava and J.D. Denardi Departamento Bioquimica, UNESP, Araraquara, S.P., Brazil
Cultures isolated from sedimentation tanks containing anaerobic citrus wastes, cultured in Pfennig’s medium under illuminated conditions, were identified as R. acidophila and R. palustris. This was confirmed by metabolism of carbon sources (acetate, arginine, aspartate, benzoate, caproate, citrate, casein amino acids, ethanol, yeast extract, formate, fructose, fumarate, glycerol, glucose, glutamate, lactate, malate, malonate, niacin, methanol, propionate, succinate, tartarate, thiosulphate, valerate). Absorbance spectra of the photosynthetic pigments of the two species were similar, showing maxima of 380-390, 500-520 and 600nm. Preliminary treatments tested were: a) behaviour of the inoculum in raw waste; comparison of absorbance values obtained in the waste and in synthetic medium showed satisfactory production of bacterial biomass; b) determination of COD; enriched and non-enriched wastes showed reductions of 39.92 and 17.54%, respectively; c) detoxification of the waste by bacterial action, demonstrated by the presence of limonen.
Growth Kinetics of a Pseudomonas sp. in the Presence of the Herbicide Clomazone
Pesticide Degradation: the Brazilian Scene
M.L.T. Mattos and R.W.S.P. Thomas
R.T.R. Monteiro
Faculdad de AgronomialUFRGS,
Centro de Energia Nuclear na Agricultura, Piracicaba, SP, Brazil
The earlier biodegradation studies of pesticides in soils in Brazil, using radiolabelled material 14C02 technique, began in the late 70s. The use of this technique allows us to differentiate between the 14C02 evolved from microbial breakdown of an :-r__>..__> ,.-A __.^,..,.A E-,.,,,LI”UUc;CU--“r:-:_JI.‘CSL’~;‘UL a,,Ll AL,. LIE nA L-v2 E;““I”~U ll”lll -:-..,L:“, IIII~L”“I(II breakdown of soil organic matter components. In 1990, IBAMA published its guidelines for tests to evaluate the ecotoxicity of chemical agents. In the same year, new legisla-
a
Porto Alegre, RS, Brazil
Bacteria resistant to the herbicide Clomazone were isolated from a planosol in Rio Grande do Sul. One of the isolates was identified as a probable Pseudomonas. Growth curves of this organism were determined in mineral medium containing 200 mg/l Clomazone. In some cases mannitol was added at the same concentration. The number of generations per hour (PC> _^-_-.r:-. ,l-+-..-:--A -a-l.Zfid the gcmt;lauuu iiilie (Tgj iiieiX UC;LGIIIIIIIC;U. 111~; J%?iid9monas sp. was able to grow with Clomazone
as sole carbon source. The highest growth rate occurred at the beginning and after 24 h (p = 0.270/h, Tg = 3.589 h). Cell numbers at the end
Abstracts
Biodegradation of Petroleum in “Piletas” in the v--A_ In..-L-1 la-L--,,~EPTCII III LWlUitl l-2Wl~UlUii O.H. Pucci, M. Bak and S.R. Peressutti C.E.I.M.A. Universidad National de La Patagonia San Juan Bosco, Comodoro Rivadaia, Argentina
In petroleum exploration, from the perforation of the well to the procedures of repair and maintenance, a great quantity of oily wastes and petroleum residues is produced. Over many years, these have been buried in holes next to the well, called “piletas”. These holes were not rendered impermeable, the only requirement being that they are enclosed. In Central Patagonia, Argentina, oil exploration activities have been intense since the beginning of the century and these “piletas” have been subjected to increasing criticism in the last few years because of.the damage being done to the environment and m.n~r;~ll,r h;rdc the ~~yvv’u”, tn L” m;avot;nn ““~‘U”“~ “II.&“. Tn 1111001 ‘/Id, l&l” Pc=rr.darv “““~CY’J fnt I”. Fn~rov Y..V’bJ
laid down a timescale for the elimination by the oil companies of these “piletas” of high risk. This has resulted in various companies proposing the use of their own bacterial strains for the elimination of the offending oils. The present report is a study of the processes which occur in these “piletas” and the behaviour of the inoculated bacteria.
Biodegradation of Organochlorine Compounds A. Neilsen IVL, Stockholm, Sweden
Organochlorine compounds have attracted interest since the discovery of chloroform as an anaesthetic, chloral hydrate as a sedative and more recently DDT as an insecticide. The value of - ?many industriai products such as PCBs depends on their chemicai stability, and many compounds including agrochemicals contain chlorine. In addition, a large and structurally diverse group of organochlorine compounds is produced by a range of biota, while some are by-products from the bleaching of pulp by conventional procedures using molecular chlorine. The chemical stability of organochlorine compounds is reflected in their resistance to microbial degradation, and this fact coupled to their ubiquitous occurrence in environmental samples has aroused widespread concern. The mechanisms of microbial degradation of aliphatic and aromatic organochlorine compounds include hydrolytic, oxidative, reductive and elimination mechanisms. These will be reviewed with reference to their limitations, the range of structures that have been studied, and attention drawn to the environmental consequences of biotransformation. Illustrative examples will be drawn from studies with chloroalkanes, and a range of aromatic compounds including hydrocarbons, carboxylic acids, phenols and anilines. Attention will be directed to important environmental constraints including anaerobic conditions and bioavailability, and brief mention will be made of the degradation of organofluorine and organobromine compounds to highlight the differences from organochlorine compounds.
tion was instituted which obliged chemical industries to have their standard laboratory measurements done in Brazilian laboratories. Nowadays, most of the pesticides registered in Brazil have their degradation studies developed under appropriate soil and climatic conditions.
Toxicity Effects on Anaerobic Biodegradation:
Case Study D.R. Paula Jr” and E. Forestb “University of Campinas, Agricultural Engineering School, Carnpinas, SP, and bUniversity of Sdo Paulo, Engineering School of S&o Carlos, Brazil
Sulfide toxicity studies were carried out using a lab-scale (10.5 1) UASB reactor operated continuously during 12 months under progressive increase of influent Na$ concentrations. NazS was directiy added to the synthetic substrate jbased on giucose and nutrient solution) in the feeding tank to obtain the desirable influent sulfide concentrations ranging from 10 to 500 mg/l. The influent COD concentration of 2000 mg/l and the hydraulic retention time of 15.6 h were maintained constant during the experiment. Stimulation effects were detected up to the sulfide concentration of 100 mg/l. Toxicity effects arose for sulfide concentrations beyond that value with gradual efficiency reduction (from 98 to 70% COD removal) to 500 mg/l of sulfide.
Treatment of Liquid Residues of the Citrus Fruit Industry by Photosynthetic Bacteria Rhodopseudomonas acidophila and R. palustris P.M. Lacava and J.D. Denardi Departamento Bioquimica, UNESP, Araraquara, S.P., Brazil
Cultures isolated from sedimentation tanks containing anaerobic citrus wastes, cultured in Pfennig’s medium under illuminated conditions, were identified as R. acidophila and R. palustris. This was confirmed by metabolism of carbon sources (acetate, arginine, aspartate, benzoate, caproate, citrate, casein amino acids, ethanol, yeast extract, formate, fructose, fumarate, glycerol, glucose, glutamate, lactate, malate, malonate, niacin, methanol, propionate, succinate, tartarate, thiosulphate, valerate). Absorbance spectra of the photosynthetic pigments of the two species were similar, showing maxima of 380-390, 500-520 and 600nm. Preliminary treatments tested were: a) behaviour of the inoculum in raw waste; comparison of absorbance values obtained in the waste and in synthetic medium showed satisfactory production of bacterial biomass; b) determination of COD; enriched and non-enriched wastes showed reductions of 39.92 and 17.54%, respectively; c) detoxification of the waste by bacterial action, demonstrated by the presence of limonen.
Growth Kinetics of a Pseudomonas sp. in the Presence of the Herbicide Clomazone
Pesticide Degradation: the Brazilian Scene
M.L.T. Mattos and R.W.S.P. Thomas
R.T.R. Monteiro
Faculdad de AgronomialUFRGS,
Centro de Energia Nuclear na Agricultura, Piracicaba, SP, Brazil
The earlier biodegradation studies of pesticides in soils in Brazil, using radiolabelled material 14C02 technique, began in the late 70s. The use of this technique allows us to differentiate between the 14C02 evolved from microbial breakdown of an :-r__>..__> ,.-A __.^,..,.A E-,.,,,LI”UUc;CU--“r:-:_JI.‘CSL’~;‘UL a,,Ll AL,. LIE nA L-v2 E;““I”~U ll”lll -:-..,L:“, IIII~L”“I(II breakdown of soil organic matter components. In 1990, IBAMA published its guidelines for tests to evaluate the ecotoxicity of chemical agents. In the same year, new legisla-
a
Porto Alegre, RS, Brazil
Bacteria resistant to the herbicide Clomazone were isolated from a planosol in Rio Grande do Sul. One of the isolates was identified as a probable Pseudomonas. Growth curves of this organism were determined in mineral medium containing 200 mg/l Clomazone. In some cases mannitol was added at the same concentration. The number of generations per hour (PC> _^-_-.r:-. ,l-+-..-:--A -a-l.Zfid the gcmt;lauuu iiilie (Tgj iiieiX UC;LGIIIIIIIC;U. 111~; J%?iid9monas sp. was able to grow with Clomazone
as sole carbon source. The highest growth rate occurred at the beginning and after 24 h (p = 0.270/h, Tg = 3.589 h). Cell numbers at the end