Complete biological reductive transformation of tetrachloroethene to ethane.
Reductive dechlorination of tetrachloroethene (perchloroethylene; PCE) was observed at 20 degrees C in a fixed-bed column, filled with a mixture (3:1) of anaerobic sediment from the Rhine river and anaerobic granular sludge. In the presence of lactate (1 mM) as an electron donor, 9 microM PCE was dechlorinated to ethene. Ethene was further reduced to ethane. Mass balances demonstrated an almost complete conversion (95 to 98%), with no chlorinated compounds remaining (less than 0.5 micrograms/liter). When the temperature was lowered to 10 degrees C, an adaptation of 2 weeks was necessary to obtain the same performance as at 20 degrees C. Dechlorination by column material to ethene, followed by a slow ethane production, could also be achieved in batch cultures. Ethane was not formed in the presence of bromoethanesulfonic acid, an inhibitor of methanogenesis. The high dechlorination rate (3.7 mumol.l-1.h-1), even at low temperatures and considerable PCE concentrations, together with the absence of chlorinated end products, makes reductive dechlorination an attractive method for removal of PCE in bioremediation processes.
de Bruin
W P
WP
Department of Microbiology, Wageningen Agricultural University, The Netherlands.
Kotterman
M J
MJ
Posthumus
M A
MA
Schraa
G
G
Zehnder
A J
AJ
D004980:Ethane / Q000493:pharmacokinetics; D008658:Inactivation, Metabolic; D010084:Oxidation-Reduction; D013750:Tetrachloroethylene / Q000493:pharmacokinetics*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics
D014874:Water Pollutants, Chemical; D004980:Ethane; D013750:Tetrachloroethylene