高效聚合氯化铝对超滤膜污染影响的中试研究

针对某水厂以超滤为核心的短流程水处理工艺,在通过聚氯乙烯(PVC)超滤膜之前选择不同投加量(5、10、15和20 mg/L)的高效聚合氯化铝(HPAC)对长江下游原水进行混凝处理。通过跨膜压差(TMP)增长趋势、CODMn的去除率以及混凝后的水质,可知HPAC的最优投加量为15 mg/L。在此投加量下,运用体积排阻色谱法分析原水、膜前水、膜后水中各相对分子质量有机物的变化,可以发现混凝去除有机物的效果要优于超滤截留的。继而将HPAC与另外4种常用混凝剂:硫酸铝(分析纯)、氯化铁(化学纯)、聚合氯化铝(PAC)、聚合硫酸铁进行对比,结果表明,在它们各自最优投加量下,HPAC能够更有效地减缓超滤膜TMP的增长率,从而降低膜污染。因此,认为HPAC是与PVC超滤合金膜契合效果最佳的混凝剂。

A pilot study on influence of high performance poly-aluminum chloride on ultrafiltration membrane fouling

In order to find out the optimal dosage for the in-line coagulation combined with UF membrane process in a water treatment plant.Different dosages (5,10,15 and 20 mg/L) of high performance poly-aluminum chloride (HPAC) were performed in a pilot scale to treat the raw water from Yangtze River before PVC UF membrane filtration.According to the variations of TMP (trans-membrane pressure),the removal efficiency of COD_Mn and the water quality after coagulation,15 mg/L was determined as the optimal dosage of HPAC.In addition,HP-SEC was employed to examine the distribution of MW in raw water,coagulated and filtration effluent,indicating that the coagulation process could remove organic matter efficiently.After that,other four coagulants (Al₂(SO₄)₃,FeCl₃,PAC,PFS) were compared with HPAC,and it can be concluded that the incensement of TMP could be alleviated by using HPAC as a pretreatment.The results indicated that HPAC was the best coagulant which could prevent the membrane fouling.