Cometabolic reduction of bromate by a mixed culture of microorganisms using hydrogen gas in a gas-lift reactor.
The discharge of bromate, a suspected carcinogen, will be restricted in the near future. To assess the possibility of biotechnological treatment of bromate-containing wastewaters, the removal of bromate by chlorate-reducing microorganisms was studied. The removal of bromate and chlorate was studied in laboratory gas-lift bioreactors supplied with hydrogen gas as electron donor in the absence of molecular oxygen. In these reactors, bromate was reduced cometabolically by chlorate-respiring microorganisms. To allow the cometabolic reduction of bromate, a chlorate:bromate molar ratio of at least 3:1 was required. The cometabolic conversion permitted almost complete reduction of bromate into bromide at hydraulic retention times of at least 6 h. Optimal bromate reduction activity was observed at approximately 35 degrees C. The pH optimum was between 7 and 8. Bromate reduction in excess of 80% and a maximum bromate reduction rate of 2.3 g l(-1) day(-1) in a pilot-scale gas-lift bioreactor demonstrates that the process is sustainable.
van Ginkel
C G
CG
Akzo Nobel Chemicals, P.O. Box 9300, Arnhem, 6800 SB, The Netherlands. kees.vanginkel@akzonobel-chemicals.com
Middelhuis
B J
BJ
Spijk
F
F
Abma
W R
WR
D000393:Air Pollutants / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors; D001959:Bromates / Q000378:metabolism*; D005740:Gases; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods*; D010100:Oxygen / Q000378:metabolism; D012492:Salts / Q000378:metabolism; D012722:Sewage / Q000382:microbiology; D013696:Temperature
D000393:Air Pollutants; D001959:Bromates; D005740:Gases; D012492:Salts; D012722:Sewage; D006859:Hydrogen; D010100:Oxygen