Advanced treatment of sludge water from water treatment plant by enhanced coagulation
强化混凝工艺深度处理给水厂排泥废水

Integrated treatment and recycle of wastewater from water treatment plants becomes new trend and target to save water in water industry.The advanced treatment of filtrate from sludge water was tested by using enhanced coagulation.Results of jar tests and DOM characterization showed that HPAC was the optimum coagulant for filtrate treatment,and the proper dose was 650 mg/L.Removals of COD,TOC,turbidity and color were reached by 82.5%,89.8%,95% and 92.5% with a final value as 59 mg/L,8.46 mg/L,2.35 NTU and 13 degrees,respectively.The effluent COD meets the criteria of the Integrated Wastewater Discharge Standard(GB 8978-1996).Furthermore,the experimental results revealed that molecular weight(MW) of organics removed by polyaluminium chloride(PAC),HPAC or ferric chloride were mainly >1 300 Da,while between 744~1 300 Da was only limitedly removed.