Evaluation of 4-Chlorophenol Biodegradation by Arthrobacter chlorophenolicus A6 in an Upflow Packed Bed Reactor

Chlorinated phenols are listed under priority pollutants and their concentration in industrial effluent even reached to 1000 mg l(-1). However, investigation on biodegradation of chlorophenol at such high concentration is found to be scanty. The present study investigated biodegradation of 4-chlorophenol (4-CP) by Arthrobacter chlorophenolicus A6 in a upflow packed bed reactor (PBR) by varying its influent concentration from 400 mg l(-1) to 1000 mg l(-1), and hydraulic retention time (HRT) between 24 h and 7.5 h. Almost complete removal of the pollutant and 97.85% effluent toxicity removal were achieved in the PBR at a pollutant loading rate of 1707 mg l(-1) day(-1) or lesser. However, at higher pollutant loading rates, the reactor performance deteriorated due to temporary accumulation of toxic intermediates such as 4-chlorocatechol. Furthermore, response of the PBR under shock loading condition was tested and the PBR system found to have good compatibility in handling shock loadings.