饮用水水源突发性铊污染应急处理试验研究

Experimental study on the emergency treatment of drinking water source accidents caused by thallium pollution

模拟自来水厂现有工艺对含铊(Tl)原水进行处理,含Tl质量浓度为0.15μg/L的原水在处理后剩余Tl质量浓度为0.142μg/L,未能达到世界饮用水卫生标准规定的0.1μg/L限值。在水厂现有工艺基础上,通过投加高锰酸钾、粉末活性炭和调节pH值来强化Tl去除。单因素试验和正交试验结果表明,高锰酸钾对Tl去除有极显著影响。最佳去除率方案为:高锰酸钾1.00mg/L,pH值9.00,粉末活性炭30.0mg/L,聚合氯化铝铁1.88 mg/L。在此条件下处理Tl质量浓度为0.336μg/L的原水,出水剩余Tl质量浓度为0.045μg/L,同时该条件能使质量浓度低于1.24μg/L的Tl污染原水处理后达标。以经济投药方案处理Tl质量浓度为0.336μg/L的原水,出水Tl质量浓度为0.081μg/L,而每吨水的制水成本较原工艺仅增加0.021元。该投药方案也适用于质量浓度低于0.64μg/L的Tl污染原水。研究表明,在应对饮用水水源突发性Tl污染时,可采用高锰酸钾预氧化强化混凝应急处理。

The given paper intends to present the results of our experimental study of an improved emergency treatment of the water resources contaminated by thallium. In our study, we have evaluated the thallium-removal efficiency through laboratory tests, which is by nature a simulated treatment for the time being. The results of our experiments show that the currently adopted treating process, though is able to remove part of contaminants （e. g. it can make thallium mass concentration reduced from 0.15 μg/L to 0. 142μg/L）, the remaining thallium concentration would not be able to meet the drinking water standard demands. And, therefore, it would be necessary to enhance the coagulation with potassium permanganate （KMnO4） preoxidation and the activated carbon adsorption process for heightening the thallium efficiency. Single factor analysis tests also prove that the removal capacity of thallium can be improved by increasing the dosage of KMnO4 and pH value, when the dosage of KMnO4 exceeded 1mg/L with pH value higher than 9, it would be possible to keep the same removal efficiency. The orthogonal test indicates that KMnO4 may have a significant impact on the removal efficiency of thallium. Actually we can have two processes from the orthogonal test： one is the optimal process, which can be achieved by dosing KMnO4 of 1.00 mg/L, with pH value of 9, with activated carbon of 30 mg/L, and PAFC of 1.88 mg/L; the other is the economical process, which can be done by adding KMn04 of 1.00 mg/L, with pH value of 8.5, and PAFC of 1.4 mg/L. Compared with the initial mass concentration of thallium 0.336 μg/L, the thallium mass concentration can be reduced to 0.045 μg/L under the condition of optimal process, and 0.081 μg/L under the economical condition. However, though the removal rate proves the optimal process, the outflow water quality un- der the economical condition tends just to be better in terms of pH value, turbidity and CODMn. Nevertheless, the optimal process could treat the raw water with the mass concentration of thallium lower than 1.24μg/L, while the economical process could treat water whose concentration of thallium is lower than 0.64μg/L.