高锰酸钾预氧化对大肠杆菌DBPsFP的去除

以大肠杆菌为试验对象，采用高锰酸钾（KMnO₄）预氧化法，研究了不同的高锰酸钾浓度、氯化时间、pH值、预氧化时间及反应温度在氯化消毒过程中对大肠杆菌消毒副产物生成潜能（DBPsFP）的去除影响.研究表明：随着KMnO₄浓度的增加，二氯乙腈（DCAN）、三氯乙腈（TCAN）、1，1，1-三氯丙酮（1，1，1-TCP）及三氯乙醛（CH）浓度先降低，后升高，1，1-二氯丙酮（1，1-DCP）浓度先升高，后降低；三氯甲烷（TCM）浓度逐渐降低.在KMnO₄浓度2mg/L时，DCAN、TCAN、1，1，1-TCP浓度降至最低，对大肠杆菌DBPsFP的氧化去除效果最好；延长氯化时间，TCAN，1，1-DCP浓度逐渐升高，而DCAN，CH和1，1，1-TCP浓度先升高后降低.TCM浓度先升高后趋于稳定；pH值由5升高到9时，1，1，1-TCP、TCAN浓度不断地降低；DCAN浓度先降低，再升高；而1，1-DCP、CH浓度先升高，再降低；延长预氧化时间，TCAN、DCAN、TCM的浓度逐渐降低；1，1-DCP、1，1，1-TCP的浓度先升高，再降低；CH的浓度先升高，之后趋于稳定；随着反应温度的升高，1，1-DCP、DCAN的浓度逐渐升高；1，1，1-TCP浓度则逐渐降低；TCAN、TCM的浓度先升高再降低，而CH浓度则先降低再升高.综上，在KMnO₄浓度2mg/L，氯化时间48h，碱性条件（pH > 8），预氧化时间30min时最有利于大肠杆菌DBPsFP的去除.

The removal of Escherichia coli DBPsFP by potassium permanganate pre-oxidation process

Experiment object was Escherichia coli. The objective of present study is to investigate the removal characteristics of Escherichia coli, as the disinfection by-products precursors during chlorination process by potassium permanganate preoxidation process under different conditions. Evaluated factors included potassium permanganate concentrations, chlorination time, pH value, preoxidation time, reaction temperature. Results showed that the concentration of dichloroacetonitrile (DCAN), trichloroacetonitrile (TCAN), 1,1,1-trichloropropanone (1,1,1-TCP) and trichloroacetaldehyde (CH) initially decreased and then increased, and 1,1-dichloropropanone (1,1-DCP) initially increased and then decreased, trichloromethane (TCM) decreased gradually with increased potassium permanganate concentrations. In this study, the concentration of DCAN, TCAN and 1,1,1-TCP decreased to the lowest and achieved optimized removal efficiency with the potassium permanganate concentration reached 2mg/L; With the prolonged chloration time, the concentration of TCAN, 1,1-DCP increased gradually. The concentration of DCAN, CH, 1, 1, 1-TCP initially increased and then decreased. The concentration of TCM initially increased and tend to be stable; With the increased of pH from 5 to 9, the concentration of 1,1,1-TCP、TCAN decreased gradually. The concentration of DCAN initially decreased and then increased. The concentration of 1,1-DCP、CH initially increased and then decreased; With the prolonged pre-oxidation time, the concentration of TCAN, DCAN, TCM decreased gradually. The concentration of 1,1-DCP, 1,1,1-TCP initially increased and then decreased. The concentration of CH initially increased and tend to be stable; With the increased of temperature, the concentration of 1,1-DCP、DCAN increased gradually. The concentration of 1,1,1-TCP decreased gradually. The concentration of TCAN、TCM initially increased and then decreased. The concentration of CH initially decreased and then increased. In conclusion, to attain optimized removal efficiency for the disinfection by-products precursors of Escherichia coli. It is suggested from this study that the potassium permanganate concentration should reach 2mg/L, under chloration time of 48h, alkaline condition (pH > 8), and pre-oxidation time of 30min.