高锰酸钾助凝铝盐混凝剂处理低浊水效能及对出水残余铝的影响

以低浊微污染配水为试验水样,对比考察了硫酸铝(Al₂(SO₄)₃)、氯化铝(AlCl₃)和聚合氯化铝(PACl)的混凝效能;考察高锰酸钾(KMnO₄)对铝盐混凝剂的助凝效果及对出水中残余颗粒铝(Al_P)和溶解铝(Al_D)含量的影响;并对残余铝形态与除污染效果的相关性进行分析。结果表明:AlCl₃、Al₂(SO₄)₃混凝效能相似,二者电性中和能力较PACl强,但去除浊质及溶解性有机物效果不如PACl。KMnO₄对AlCl₃、PACl絮体zeta电位的影响随其投量的增加有小幅下降,同时,KMnO₄能有效地降低出水中剩余浊度与溶解性有机物含量,对AlCl₃、PACl的助凝作用主要体现在电性中和阶段。KMnO₄也能有效地降低出水中Al_P与Al_D含量,且残余铝多以Al_P的形式存在,Al_D含量相对较低;相同混凝剂投量下,Al_P与剩余浊度存在一定的正相关性,而残余Al_D含量受KMnO₄以及铝盐混凝剂投量的双重影响。以网捕卷扫为主导时,Al_D含量较稳定,在较小范围内波动。

Effect of potassium permanganate on efficiency of alum-based coagulants and on content of residual and dissolved aluminum in treatment of low turbidity water

For treatment of light pollution water with low turbidity,the investigation was made on coagulation efficiency of Al₂(SO₄)₃,AlCl₃,and PACl as well as effect of potassium permanganate on efficiency of alum-based coagulants and on content of residual particle aluminum(Al_P) and dissolved one(Al_D),and a relativity analysis also made on between form of Al_P and removal performance.The results show that there is similar coagulation efficiency for Al₂(SO₄)₃ and AlCl₃,because their ability of charge neutralization is better than PACl.However,for removal of turbidity and dissolved organics,PACl is better than Al₂(SO₄)₃ and AlCl₃.The effect of KMnO₄ on zeta potential of AlCl₃ and PACl flocs weakens gradually with increase of its dosage,while that of KMnO₄ on removal of turbidity and dissolved organic matter goes up,mainly in the stage of charge neutralization.Moreover,the content of Al_D and Al_P,mainly Al_P, decreases obviously by use of KMnO₄.At the same dosage of these coagulants,there is a positive correlation between the content of Al_P and residual turbidity,but content of Al_D is influenced by dosage of both KMnO₄ and coagulants,especially,is relatively stable when sweep flocculation is in the ascendant.