An innovative bioprocess that rapidly and completely dechlorinates chlorinated ethenes

摘要

Dechlortnation of chlorinated ethenes, common groundwater contaminants, was investigated using anaerobic granular sludge exposed to O_2. The exposure established a synchronously anaerobic/aerobic bioconversion process, i.e. reductive dechlorination in combination with aerobic co-oxidation. Experimental results showed that the highest dechlorination rate of tetrachloroethene (PCE), trichloroethene (TCE), cis-dichloroethene (cDCE) and vinyl chloride (VC) was 6.44, 2.98, 1.70 and 0.97nmol/g VSd, respectively, at an initial O_2 concentration of 10, 100, 5 and 0%. Strictly anaerobic conditions favored VC dechlorination and absolutely aerobic conditions was preferred for TCE dechlorination. Considering that both rapid and complete dechlorination are required in overall biodegradation of the chlorinated ethenes, microaerophilic conditions, i.e. 5-10% O_2, are suggested as for a potential process.