紫外-氯顺序灭活地下水源水中真菌的效能

Sequential inactivation of fungi in drinking groundwater by UV and chlorine

以地下水源水中真菌为研究对象,研究了单独紫外线灭活、单独氯灭活以及紫外线-氯顺序灭活的灭菌效果,同时对单独消毒剂灭活进行了动力学研究,确定了其动力学参数。结果表明:单独紫外线灭活时,在相同紫外剂量(I·t)下,高紫外强度(I)下真菌的灭活效果优于低紫外强度的灭活效果;紫外线灭活符合一级光化学反应,其速率常数k为0.044~0.077 cm2·(m W·s)^(-1)。单独氯灭活时,氯浓度2.0 mg·L^(-1),作用30 min,真菌灭活率达到95%;氯衰减符合一级衰减模型,即氯灭活真菌符合一级动力学反应,其速率常数k为0.056~0.081 L·(mg·s)^(-1)。紫外线-氯顺序灭活时,高紫外剂量-低加氯量可以达到低紫外剂量-高加氯量的灭活效果;真菌完全灭活时,紫外剂量从5 m J·cm^(-2)增加到30 m J·cm^(-2),加氯量可降低1~2 mg·L^(-1),减少了消毒副产物的生成量,降低了生态环境风险;紫外线与氯顺序灭活具有协同效应。

The inactivation effect of fungi in groundwater was studied. Individual UV and chlorine,disinfection,as well as sequential disinfection with UV followed by chlorine were examined. Meanwhile,the disinfection kinetics of UV and chlorine were investigated and the relevant parameters were obtained. The results revealed that under the same UV dose（ I·t）,the UV intensity（ I） influences fungal inactivation and at higher UV intensity,enhanced fungal inactivation was achieved with UV alone. The UV disinfection process was in accordance with the first-order kinetics with a rate constant k of 0. 044 to 0. 077 cm2·（ m W·s）^-1. Approximately 95% of fungi could be inactivated by 2. 0 mg·L^-1of chlorine after a 30 min contact time. The chlorine disinfection process was also in accordance with the first-order kinetics with the rate constant k of 0. 056 to 0. 081 L·（ mg·s）^-1. The inactivation effect of higher UV dose and lower chlorine concentration could be similar to that of lower UV dose and higher chlorine concentration in a UV-chlorine combination process. When the fungi were completely inactivated,the concentration of chlorine can be reduced from 1 to 2 mg·L^-1by improving the UV dose from 5 m J·cm^（-2）to 30 m J·cm^（-2）. Therefore,UV-chlorine combination process could significantly reduce the disinfection by-products and environmental risks. The sequential inactivation of fungi using UV and chlorine is an example of synergistic effect.