[Study on biodegradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols]

Purpose of this study was to determine the treatability of 2,4-dichlorophenol (2,4-DCP) by anaerobic granular sludge which was acclimated by mixed mono-chlorphenols (2-CP, 4-MCP). The characteristic of degradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols was investigated through shake flask study and performance of continuous flow anaerobic bioreactors. The difference of degradation of 2,4-DCP by acclimated and unacclimated sludge was also compared. 2,4-DCP was degraded at 50 h and 180 h respectively for acclimated and unacclimated sludge, which testified that acclimated sludge could more effectively degrade 2,4-DCP. Although the intermediate product 4-MCP was present in both reaction system, 4-MCP could be degraded completely after 400 h in the acclimated sludge but accumulated in the unacclimated sludge. Therefore, acclimation by the mixed mono-chlorphenols (2-CP, 4-MCP) could enhance the ability of para- and meta-dechlorination for anaerobic sludge and increase the treatability of 2,4-DCP. The results of continuous anaerobic sludge-suspended carrier bioreactor (ASSCB) indicate that inoculation of the acclimated sludge by mixed mono-chlorphenols can degrade two mono-chlorphenols simultaneously, shorten the setup period, and increase the efficiency of degrading 2,4-DCP. 2-CP was easily degraded with removal rate of over 80% . While the removal rate of 4-MCP was fluctuating within 30% - 80% with changes of its influent concentration.