University of Brescia, Department of Civil Engineering, Architecture, Land, Environment and Mathematics, via Branze 43, 25123 Brescia, Italy.
University of Brescia, Department of Civil Engineering, Architecture, Land, Environment and Mathematics, via Branze 43, 25123 Brescia, Italy.
Water Res. 2014 May 1;54:44-52. doi: 10.1016/j.watres.2014.01.038. Epub 2014 Jan 31.
Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%.
消毒是饮用水处理厂 (DWTP) 的最后处理阶段，旨在维持给水管网中的消毒剂残留浓度。二氧化氯 (ClO2) 是一种广泛用于此目的的化学物质。本工作旨在评估几种处理方法对二氧化氯消耗以及最终氧化/消毒阶段亚氯酸盐和氯酸盐形成的影响。在实验室规模下使用从 Cremona (意大利) 的 DWTP 采集的水样进行了多项测试。研究了以下过程：高锰酸钾、二氧化氯和次氯酸钠氧化、三氯化铁和硫酸铝混凝/絮凝、过滤和活性炭吸附。结果表明，如果在预氧化中使用次氯酸钠或高锰酸钾，则二氧化氯需求较高。另一方面，二氧化氯会导致亚氯酸盐和氯酸盐的生成量最高。预氧化后的混凝/絮凝过程表明，如果使用高锰酸钾作为氧化剂，无论是使用三氯化铁还是硫酸铝，二氧化氯的需求都会降低。因此，这些过程的结合会导致亚氯酸盐和氯酸盐的产量降低。就二氧化氯需求降低和亚氯酸盐和氯酸盐形成最小化而言，硫酸铝是优选的。活性炭是最有效的解决方案，因为它将二氧化氯的消耗减少了约 50%，并将 DBP 的形成减少了约 20-40%。
