Effect of Raw Water Characteristics on Sludge Reuse Process for Synthetic Low Temperature and Low Turbidity Water Treatment

Recycling ratio of mixed sludge and properties of raw water (such as pH, turbidity and organic matter concentration) were systematically investigated to optimize coagulation efficiency in current study. It was found that the appropriate recycling ratio of mixed sludge was 6%, effective initial turbidity were below 45.0 NTU, and optimal pH for dissolved organic matter and turbidity removal was 6.5-7.0 and 8.0, respectively. Residual dissolved alum (RDA) in treated water met the drinking water quality standard (<0.2 mg/L). Coagulation efficiency and RDA was not negatively influenced by organic matter concentration of 1.104-3.354mgDOC/L. Under above condition, sludge reuse process could be significant for the low temperature and low turbidity water treatment.