监控自然衰减技术作为多相抽提措施后的绿色联合修复技术，在氯苯类污染物地下水修复工程案例中存在空白，其修复效果及作用机制尚不明确。该研究以氯苯类污染场地地下水多相抽提后污染源727 d的自然衰减监控为基础，从实际工程案例的角度出发，评价氯苯类污染物的自然衰减能力，探讨作用机制。研究结果表明:在自然衰减的727d中，浅层地下水中1，2-二氯苯、1，4-二氯苯的质量浓度整体上呈下降趋势，但不符合一阶衰减模型;在416d时，1，2-二氯苯、1，4-二氯苯在脱氯菌的作用下向氯苯转化;在529 d时，存在氯苯向苯的脱氯转化。在中试开展前，场地内地下水中可能的脱氯降解菌属以Desulfomonile、Geobacter、Deha-lobacter、Desulfovibrio 为主，中试后 416 d 优势菌属转变为 Pseudomonas，到 727 d 转变为 Dehalogenimonas、Pseudomonas、Desulfovi-brio。二氯苯降解至一氯苯阶段，需要更多的脱氯菌参与，群落多样性水平较低;一氯苯降解至苯阶段，群落结构更接近无污染状态，群落多样性水平较高。中试后416 d内细菌群落结构向有氧菌转化，416d后向厌氧菌转化。该研究可为氯苯类污染地下水经济、绿色修复提供参考依据。
Natural Attenuation Microbial Response of Chlorobenzene Pollutants in Shallow Groundwater
As a green joint remediation technology after multi-phase extraction,monitored natural attenuation has gaps in chlorobenzene pollutants groundwater remediation projects,and its remediation effect and mechanism are still unclear.Based on the 727 d natural attenuation monitoring of pollution source after multi-phase extraction of groundwater in chlorobenzene contaminated sites,this study evaluated the natural attenuation capacity of chlorobenzene pollutants and discussed the mecha-nism of action from the perspective of practical engineering cases.The results show that the mass concentrations of 1,2-di-chlorobenzene and 1,4-dichlorobenzene in shallow groundwater generally decline during 727 d of natural decay,but are not consistent with the one-order decay model.1,2-dichlorobenzene and 1,4-dichlorobenzene were converted to chloroben-zene under the action of dechlorination bacteria at 416 d,and there was dechlorination of chlorobenzene to benzene at 529 d.Before the pilot test,Desulfomonile,Geobacter,Dehalobacter and Desulfovibrio are major potential dechlorine-degrading bacteria in the groundwater of the site.After the pilot test,the dominant bacterium has changed into Pseudomonas at 416 d.It is transformed into Dehalogenimonas,Pseudomonas,Desulfovibrio at 727 d.The degradation of dichlorobenzene to the chlorobenzene stage required more dechlorination bacteria,and the community diversity level was lower.When chloroben-zene degraded to benzene stage,the community structure was closer to the pollution-free state and the community diversity level was higher.After the pilot test,the bacterial community structure transformed to aerobic bacteria in 416 d,and to anaer-obic bacteria after 416 d.This study can provide reference for economic and green remediation of chlorobenzene contaminat-ed groundwater.
万方数据
维普
