混凝-超滤组合工艺运行优化研究

Optimization of Operating Conditions of Coagulation and Ultrafiltration Combined Process

采用混凝/浸没式超滤组合工艺对深圳某原水进行中试研究,从有机物去除和膜污染控制两方面对聚合氯化铝(PAC)投加量和膜池曝气强度进行了优化。结果表明,膜池气水比为12∶1,PAC投加量为0、3、4 mg/L时,Zeta电位绝对值逐渐减小,颗粒数和COD Mn去除效果增强,继续增加PAC投加量到5 mg/L,则Zeta电位绝对值增大,颗粒数和COD Mn去除效果变差。PAC投加量为4 mg/L,膜池气水比为(7.5∶1)、(9∶1)、(12∶1)时,Zeta电位绝对值逐渐减小,颗粒数和COD Mn去除效果逐渐增强,继续增大气水比到15∶1,则Zeta电位增大,颗粒数和COD Mn去除效果变差。PAC的投加和膜池曝气可减缓不可逆膜污染,增加PAC投加量可提高DOC去除率,降低单周期TMP增幅;提高曝气强度会降低DOC去除率,降低单周期TMP增幅。

The combined process of coagulation and immersed uhrafiltration was investigated for the optimization of polyaluminium chloride （PAC） dosage and aeration intensity based on the removal of organics and membrane fouling control. The results showed that the absolute value of Zeta potential de- creased, and the removal of particle counts and CODMn increased when the air-water ratio in membrane tank was 12 ： 1, and PAC dosage was 0 mg/L, 3 mg/L and 4 mg/L respectively. The absolute value of Zeta potential increased, and the removal of particle counts and CODM. decreased when increasing PAC dosage to 5 mg/L. The absolute value of Zeta potential decreased, and the removal of particle counts and CODM, increased when PAC dosage was 4 mg/L, and the air-water ratio in membrane tank was 7.5 ： 1, 9 ： 1 and 12 ： 1 respectively. The absolute value of Zeta potential increased, and the removal of particle counts and CODMn decreased when increasing the air-water ratio to 15 ： 1. Addition of PAC and aeration in membrane tank were beneficial to slow down the irreversible membrane fouling. Increasing PAC dosage could improve the removal efficiency of DOC and reduce the amplitude in transmembrane pressure in a single cycle. Enhancing aeration intensity could reduce the removal efficiency of DOC and the amplitude in transmembrane pressure in a single cycle.