Use of membrane bioreactors for the bioremediation of chlorinated compounds polluted groundwater.

Chlorinated compounds are widely used in agricultural applications where they are employed as components of pesticides; this leads often to pollution of groundwater near to agricultural sites, with serious effects for human health. The aim of the present study was the development of a membrane bioreactor, a new and effective water treatment technology, for the bioremediation of water polluted by 1,2-dichloroethane, 1,2-dichlorobenzene and 2-chlorophenol. Before starting-up the MBR system, a biomass was acclimated, to simultaneously degrade the three chlorinated compounds; then the acclimated biomass was inoculated into the MBR. The results showed a higher removal rate for 1,2-dichloroethane than for 1,2-dichlorobenzene; besides, the presence of 1,2-dichlorobenzene together with 1,2-dichloroethane decreased 1,2-dichloroethane specific removal rate. 2-chlorophenol was degraded only in presence of phenol as co-substrate, and the presence of phenol and 2-chlorophenol decreased 1,2-dichloroethane specific removal rate of approximately eight times, while 1,2-dichlorobenzene specific removal rate was not affected.