Studies On Preoxidation Of Dongjiang Source Water In Dongguan Section By Potassium Permanganate

The study mostly aimed at problems on increase of Mn²+ in Dongjiang source water in Dongguan section, filter grains of potable water treatment plants whose sources are Dongjiang becoming black, filters clogging, treated water being not up to the standard and so on, and experimented with preoxidation by potassium permanganate to remove manganese. The experiments included jar tests an pilot test, and jar tests were taken in the third Dongjiang potable water treatment plant in Dongguan, while the pilot test was taken in the forth potable water treatment plant.Experiments were mainly about relationship between dose of potassium permanganate and effect of manganese removal and factors affecting the effect of manganese removal. In addition, when attaining the best effect of manganese removal, effects of preoxidation by potassium permanganate on coagulation and removal of organic pollutant (TOC, CODMn, UV₂54) of raw water, and economical benefit were studied.Experiment results revealed that potassium permanganate had very good effect of manganese removal when the dose was 0.2⁰.5mg/1. The average removal rate of Mn²+ in settled water was up to 58.9%⁸3.7%, and the residual concentrations of Mn²+ were all below 0.3mg/l. The removal rate of Mn²+ in pilot test was 40.8%, which confirmed the results of jar test.It was found that pH greatly impacted on the effect of manganese removal, and the higher the pH was, the better the effect would achieve. So it was highly advantageous for attaining favorable effect of manganese removal to increase pH. At the same time, time of preoxidation, which was the time of potassium permanganate adding before coagulant, impacted on the effect of manganese removal to some extent, the longer the time of preoxidation was, the better the effect would be.