黄浦江原水中各类有机物在铝盐混凝过程中的去除效果

通过XAD-8/XAD-4吸附树脂联用技术将黄浦江微污染原水中溶解性有机物分为疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物,研究了铝盐混凝工艺对黄浦江水中4类有机物的去除效果.硫酸铝在最佳混凝条件下,即投加量为8 mg·l~(-1)(以Al计),pH=5.5时,水中的DOC和UV_(254)的去除率分别达到23%和32%.有机物的亲疏水性对混凝工艺有较大影响,混凝法倾向于优先去除水中疏水性有机物,而疏水性有机物的酸碱性对混凝工艺没有明显影响,酸性和非酸类疏水物质均能破混凝工艺所去除.疏水酸是水中最主要的三氯甲烷类消毒副产物的前体物质,混凝工艺对于三氯甲烷类消毒副产物有良好的控制作用,总体减少了 39%的生成量.而不同类的有机物之间,混凝工艺对消毒副产物控制效果不同,其中对疏水酸的控制三氯甲烷消毒副产物的效果最好,减少了63%的生成量,亲水物质的控制效果最差,三氯甲烷生成量仪减少了3%.疏水酸表现出比亲水物质更强的生物毒性,混凝工艺能明显降低原水的毒性.

STUDY ON REMOVAL EFFECT OF DIFFERENT ORGANIC FRACTIONS FROM MICRO-POLLUTED RAW WATER BY COAGULATION

Dissolved organic matter (DOM) in the water from Huangpu river was separated by XAD-8 and XAD-4 resins into four fractions: hydrophobic acids, non-acid hydrophobics, transphilics and hydrophilics. The paper focused on the removal effect of the four different fractions through the coagulation process by aluminum salts. The best aluminum salts coagulation condition for the water from Huangpu river is as followed: 8mg ·l~(-1)(Al)as the best dosage, and pH =5.5 as the best pH. Under the best conditions, Aluminum salts removed UV-absorbing substances achieving 32% reduction in UV_(254) ; and it also resulted in a 23% reduction in dissolved organic carbon (DOC). DOM's hydrophobicity had noticeable effect on coagulation process. Hydrophobic acids were mostly removed by coagulation process. However, acidity-alkalinity of DOM made no difference. Hydrophobic acids were the most activated trihalomethanes precursors in the water. The coagulation process had a sound effect of trihalomethanes control, achieveing the total trihalomethanes removal ratio to 39%. For different kinds of organic fractions, the coagulation process controlled the disinfection by-products (DBPs) to different extent. For the bydrophobic acids, coagulation process achieved the reduction of trihalomethanes 63%, while for the hydrophilics, only resluted in 3%. The hydrophobic acids in the water performed more toxic than the hydrophilics. After the coagulation process, the toxicity of both two organic fractions were obviously removed.