Short chain chlorinated paraffins SCCPs are priority hazardous substances classified by the European Water Framework Directive and have been detected in sewage sludge of wastewater treatment plants worldwide. However, studies on the biodegradation of SCCPs presented in sewage sludge are very scarce.
In this study, a bacterial strain that can utilize SCCPs as a sole source of carbon and energy was isolated from soil. This strain was identified as Pseudomonas sp. N35. The efficacy of SCCP degradation by strain N35 was tested in pure culture and sewage sludge microcosms containing 66.1 mg kg–1 SCCPs. The results showed that 57.5% of chloride was released into the medium as chloride ions in pure culture within 20 days. Mesophilic temperature and near-neutral pH were most favorable for SCCP degradation. The addition of low concentrations of glucose, Tween-80 and acetone (20 mg L–1) enhanced SCCP degradation. Bioaugmentation resulted in 73.4% removal of SCCPs in the sludge microcosm after 30 days of treatment.
Bioaugmentation with specific strains may be of great significance in bioremediation of SCCP-containing sewage sludge.© 2012 Society of Chemical Industry