The Study Of Organic Matter Removal In Drinking Water Treatment By MIEX-coagulation Combined Process

The removal of organic matter in traditional water treatment process is generally not efficient, and disinfection by-products might be formed in the chorine disinfection unit, which was considered to be harmful to human health. Magnetic ion exchange resin (MIEX) is a kind of anion exchange resin with very high organic matter removal efficiency. In this study, MIEX absorption technique was introduced to the traditional water treatment process, combined with coagulation units to form a new MIEX-COA process. The removal of natural organic matter, turbidity and anion were analyzed to evaluate the combined process, and the main conclusions are as following:1. The influence of MIEX dosage, mixture time and dosing order were investigated by the removal of DOC and UV254. The results showed that the optimum dosage for PFC and MIEX are 4 mg/L and 16 mL/L, the optimum mixture time is 15 min and MIEX pretreatment followed by coagulation could get the best removal2. MIEX-COA process could significantly improve the removal of organic matter compared with the traditional coagulation process. The mechanisum was analysed by the molecular weight distribution of organic matter and the particle size distribution of flocs.3. The role of several factors in the MIEX-COA process were investigated by determining the removal of DOC and UV254. The results showed that turbidity could influence the removal of some charged organic matters but gave little influence on DOC removal. Adjusting pH could influence the removal of organic matter in coagulation process, while no big difference was found in the MIEX absorption process. The influence of anion concentration was considered to be very small.4. The removal of turbidity and anions were also investigated. The results showd that MIEX absorption could not removal turbidity from surface water, but could the decrease the residual turbidity in the effluent of following coagulation process. The removal efficiency of bromide, nitrate and sulfate were 25.6%,24.5%, and 58.0%, which might be caused by the competition absorption5. The saturated resin was regenerated by NaCl solution, and the absorption behavior of regenerated resin was also investigated. It is found that MIEX resin remain excellent removal efficiency during several absorption-regeneration cycles. The results also showed that turbidity did not impact the regeneration process significantly.6. The removal of two typical trace organics, sulfadiazine and sulfamethoxazole were analyzed, and the results showed that the organic matters with small molecular weight could easily diffuse through the pores on resin surface and contact with the ion exchange point. Therefore, the organic matters could be easily removed by MIEX absorption.