南方某给水厂助凝剂投加优化实践

Practice of Optimized Dosage of Coagulant Aid in a Waterworks in South China

桂林市某新建水厂采用“预沉池—Multiflo高速澄清池—后混凝池—TGV高速滤池”的净水工艺,其中在高速澄清池的絮凝区投加助凝剂聚丙烯酰胺(PAM)提高混凝效果。水厂投运初期,高速澄清池运行良好,但生产成本偏高。本研究在保证高速澄清池出水水质的前提下,通过混凝试验及生产试验,降低PAM的投加量。结果表明,在一定范围内,保持PAC投加量一致的情况下,不同的PAM投加量对高速澄清池出水铝浓度有影响。生产试验选出的PAM投加量可实现对高速澄清池出水浑浊度和余铝的良好控制。降低PAM投加量后,每年仅药耗一项就可节约25~30万元人民币,具有显著的经济效益。试验过程及结果可为相同工艺的其它水厂的运行管理提供借鉴。

The treatment process of pre-sedimentation tank + Multiflo high speed clarification tank + post-coagulation tank + TGV high speed filter was adopted in a new-built waterworks of Guilin, which used coagulant aid PAM in the flocculation tank of the Multiflo high efficiency settling tank to enhance the coagulant effect. In the beginning of the operation, the high speed clarification tank functioned well, but the production cost was high. On the premise of ensuring the effluent quality of the high speed clarification tank, by conducting the coagulant mixing experiments and production experiments, the dosage rate of PAM was successfully decreased. The results showed that, within a certain range, under the condition of keeping the same dosage rate of PAC, different dosage rates of PAM have an impact on the aluminum concentration of the effluent of the high speed clarification tank. The PAM dozing rate selected by the production experiments could achieve good control of the turbidity and residual aluminum concentration of the effluent of high speed clarification tank. By reducing the dosage of PAM, the annual PAM consumption could save about 250,000 to 300,000 yuan, which showed significant economic benefits. The process and results of the experiments could offer some references for the operation and management to other waterworks with the same process.