Wastewater treatment efficiency of combined aluminum-starch flocculant
铝盐-淀粉复合絮凝剂污水处理效果研究

This paper examined the efficiency of a combined flocculants synthesized by aluminum and starch (noted as CAS) in treating kaolin suspension, domestic wastewater, municipal effluent and pulp-making wastewater. Jar test results showed that the flocculent performance of CAS was prior to polyaluminum-chloride (PAC) in treating different concentration kaolin suspension samples (100, 400 and 2000 mg x L(-1)). The optimal dose of CAS to each sample was 3.0, 2.0 and 2.0 mg x L(-1), being 60%, 50% and 50% of PAC, respectively. CAS also showed a priority to PAC in removing the COD and turbidity of domestic and municipal effluents. When treating pulp-making wastewater, the optimal dose of CAS was 70% of PAC. The removal rate of COD was enhanced 10%, the sludge was reduced 40%, and the sediment time was greatly shortened. It was also identified that the optimal concentration required to affect flocculation depended on the concentration and the character of the wastewater within the range examined. CAS was more effective in treating high turbidity wastewater.