Employment of Microbes Isolated from Residential Wastewater to Degrade Chlorobenzene

The performance of microbial consortia from residential wastewater to degrade chlorobenzene (CB) was investigated. The consortia were firstly exposed to high CB concentration (i.e. 0.2 mg/l) for seven months. As a result, two most dominant survivors, denoted as Yellow Colony (YC) and White Colony (WC) were isolated. In a comparison study, the mixture of WC and YC yielded three times greater maximum CB specific degradation rate, Qs (7.12 x lO^g CB degraded/g cell per hour) than the individual WC and YC did, combined. This clarified that there was a synergistic effect of YC and WC on CB degradation. Result in a continuous culture indicated that nitrogen-enriched feed (yeast extract) has improved the critical dilution rate, Dc from 0.08 hour-1 to 0.11 hour-1. This proved that the nitrogen limitation could not be ignored. Our result also indicated that no degradation was witnessed below 0.6 pg/l, where CB was almost undetectable by microbes below this threshold level. Outcomes of this study have provided useful parameter estimates for future up scaling works, or on site trial.