Study On Enhanced Coagulation Technology To Micro-polluted Source Water

In the present water pollution phenomena is very serious in our country, the traditional process of water treatment isn't able to adapt to the ceaseless water quality,so many potable water treatment plants need to change traditional technology in order to adapt polluted source water. The study is based on this situation. In the present economy situation of our country, it is appropriate to enhance coagulation treatment technology to change traditional technology.The subject is based on the study of the static experiments and the dynamic experiments. The experimental source water came from a micro-polluted lake. The effects on the enhanced coagulation that the kind of coagulant,the optimal adding dose, pH, temperature and so on has been analyzed in coagulation static experiment, and study the enhanced coagulation effect of different flocculent including of NaClO, PAC, PPC, KMnO4+PAC. The experiment results show that the optimal coagulant is Polyaluminium Chloride and its optimal adding dose is 30mg/L,which the removal rate of CODMn is 33.18%; The optimal reaction condition is controlling pH 6~7, temperature over 20℃. The source water removal rate of CODMn increase over 10% by different flocculent, and the removal rate of KMnO4+PAC is similar with PPC to source water quality while the adding dose of PPC is 1~2mg/L higher than KMnO4 at the same condition. As a result, The enhanced coagulation effect of KMnO4+PAC is the better than the others.The dynamic experiments is based on the static coagulation experiments, which include coagulation continuous experiment, prior chlorination continuous experiment, PPC enhanced coagulation continuous experiment, KMnO4+PAC enhanced coagulation continuous experiment. Based on special-quality influent water, the continuous experiment results show that only adding coagulant and chlorination is effective to remove source water pH, turbidity, colour, but effluent water CODMn can't reach the criterion for drinking water quality, that is CODMn less than 3mg/L. When adding PPC or KMnO4+PAC in the course of coagulation reaction, the effluent water pH, turbidity, colour and CODMn can reach the criterion for drinking water quality after sedimentation and filtration. By compareing the optimal adding dose of PPC and KMnO4+PAC, the result indicate that KMnO4+PAC dose is less than PPC dose at the same effluent water quality.