混凝沉淀-浸没式超滤膜处理北江水中试研究

为考察混凝沉淀-浸没式超滤膜处理北江水的可行性,通过中试试验从净水效能和膜污染两方面对其进行研究,并与水厂现有常规处理工艺进行比较.结果表明,常规工艺砂滤出水浊度平均为0.176 NTU,而混凝沉淀-超滤组合工艺出水浊度平均为0.080 NTU,其对浊度的去除效果明显优于常规工艺;常规工艺对CODMn和UV254的平均去除率分别为47.3%和43.2%,而超滤组合工艺的去除率分别为50.6%和44.0%,略优于常规处理工艺.就膜污染而言,原水直接超滤时跨膜压差增长较快;而在混凝沉淀-超滤组合工艺中,混凝沉淀的预处理作用可有效去除水中的膜污染物质,超滤膜的跨膜压差增长缓慢,系统运行稳定.采用浸没式超滤替代砂滤形成混凝沉淀-超滤组合工艺可有效提高供水的安全性.

Pilot study on hybrid coagulation-sedimentation and immersed ultrafiltration for drinking water treatment from Bei River

To evaluate the feasibility of hybrid process of coagulation,sedimentation and immersed ultrafiltration(UF) for the drinking water treatment from Bei River source water,pilot study was performed in terms of pollutants removal and membrane fouling.The performance of the hybrid UF process was also compared with that of the conventional process in the full-scale drinking water treatment plant.Results showed that in the conventional treatment process,there was still 0.176 NTU of turbidity in the sand-filtration effluent on average;while it was only 0.080 NTU in the hybrid UF process.The removal efficiencies of conventional treatment process for CODMnand UV254 were 47.5% and 42.3%,respectively,which were slightly lower than the 50.6% and 44.0% achieved by the hybrid UF process.As for the membrane fouling,it was shown that the trans-membrane pressure(PTM) would increase rapidly when direct UF of raw water was carried out.However,in the hybrid UF process,due to the pre-removal of membrane foulants by coagulation and sedimentation,the PTM development rate became much lower;and stable operation of the UF could be achieved.It is demonstrated that the hybrid UF process can improve the security of drinking water supply.