Biodegradation of 4-bromophenol by Arthrobacter chlorophenolicus A6T in a newly designed packed bed reactor

Abstract

Bromophenol is listed as a priority pollutant by the U.S. EPA. However, there has been no report on the removal of bromophenol in any biological system that is operated in a continuous mode. The efficiency of Arthrobacter chlorophenolicus A6(T) on the biodegradation of 4-bromophenol (4-BP) in a newly designed packed bed reactor (PBR) was evaluated with different influent 4-BP concentrations between 400mgl(-1) and 1200mgl(-1) and hydraulic retention times (HRTs) between 24h and 7.5h. The response of the PBR to 4-BP shock loadings was also tested, and the bioreactor was found to adequately handle these shock loadings. The percentage of effluent toxicity in the PBR was tested using mixed microbial consortia as the test species; this experiment was performed using a 4-BP influent concentration of 1200mgl(-1) and HRTs between 24h and 7.5h. A maximal 98% effluent toxicity removal was achieved when the PBR was operated at an HRT of 24h. In the present study, 4-BP was used as the sole source of carbon and energy, and the complete removal of 4-BP was achieved with 4-BP loading rates of up to 2277mgl(-1)day(-1).