Using a Two-Liquid-Phase System to Investigate the Biodegradation of Trichlorobenzenes

Due to easy volatilization of volatile organic compounds from water, it is difficult to monitor their aerobic biodegradation in the traditional single water system. Whether a two-liquid-phase system (TLPS) could overcome this obstacle and enhance the degradation of volatile contaminants? In this study, a TLPS composed of silicone oil and water was employed to investigate the biodegradation of volatile compounds, trichlorobenzenes (TCBs), by the adapted microorganisms in an activated soil. The degradation and volatilization of TCBs in TLPS and in a single water system were compared. The results showed that due to volatilization losses of TCBs, the mass balance of TCBs in a single water system was very low. In contrast, using TLPS could effectively inhibit the volatilization losses of TCBs and achieved a very good mass balance during the biodegradation process. Meanwhile, the TLPS could increase microbial activity and microbial growth during the degradation process. With TLPS, the TCB degradation was in descending order of 1,2,4-TCB > 1,2,3-TCB ≫ 1,3,5-TCB, which was related to the exposed concentration of the contaminants in soil. This study showed that TLPS could be employed as an effective tool to evaluate the biodegradation of volatile hydrophobic organic compounds, which could not be achieved with the traditional single water system.