The Research On Enhanced Coagulation To Micro-polluted Raw Water Treatment

In recently years,because of the fasted development of economy,sources water in the world have been widely polluted,the traditional water purification technique can not elimimate such contamination in the raw water.Therefore the purification technique for the micro-polluteed raw water has been an important and urgent research subject.Enhanced coagulation is widely used in potbale water treatment to remove organic pollutant in the water,it removed not only turbidiy in the water but also NOM, so it can improve the qualiy to potable water, and ensure the health of the people.Compared with the chemical oxidation,biologyoxidation, active carbon adsorption, and membrane filtration technology,the enhanced coagulation has widely used and more economical advantage.Jar test c oagulationsin laboratory and pilot scale tests with dynamic operatus have been done in this paper with reservior waters in ZhongShan Xiang Jiang River.Results show that FeC13 is better than PAFC and AS in the removal of CODMn and UV254 while it is worse in the removal of turbidiy.Polymer flocculants, have been investigated.Results show that in addition to decreasing turbidity and accelerating precipitation velocity,polymer flocculants can also decrease the concentration of organics,algae and heavy metals in solutions.Theoretical analyses have been presented in the paper about the efects of polymer flocculants.The experiments also demonstrate that cationic flocculants and some inorganic flocculants except powder active carbon have limited effects on the removalof organic matters in water. The addition of Ca(OH)2 in raw water may cause a decrease in the removal efficiency of organic matters.Researches on the conditions of coagulations how that the effects of coagulation process will be better in lower pH values. Meanwhile, the mixing intensity of coagulation is found to be key factor in d etermining the removal eficiency.The paper proposes that the lasting time of fast coagulation is also one of the primary factors af ecting the removal of organics.The comparison tests of several technological processes,including Enhanced Coagulation process,have confirmed the above results,and additionally,the Ames test showed that enhanced process with PMC flocculation can reduce the carcinogenic and mutagenic possibilities of post-chlorination. It is summaried in the theory of flocculation morpHology that the principle structure of PMC can be explained to the advantages of PMC in the removal of algae and bacteria.On the basis of experiments,the paper puts forward three suggestions about coagulation for technology improvements in water works.