再生水紫外-氯组合消毒与单一氯消毒比较分析

Comparative analysis of reclaimed water disinfection by UV-chlorine combination and single chlorine process

利用准平行光束仪对再生水进行了紫外灭活大肠杆菌试验,并考察了紫外-氯组合消毒与单一氯消毒的消毒效果。结果表明,与单一氯消毒相比,紫外-氯组合消毒可有效降低氯的投加量。在组合消毒试验条件下,大肠杆菌完全灭活,紫外剂量从3 mJ/cm2提高到5 mJ/cm2,加氯量可降低1 mg/L;灭活率相同条件下,紫外剂量与加氯量的关系符合二次三项式类型,随着紫外剂量的增加,加氯量减少的速度变小;与单一氯消毒相比,紫外-氯组合消毒可有效减少再生水中三氯甲烷的生成量。在大肠杆菌完全灭活条件下,与紫外剂量10 mJ/cm2、加氯量1 mg/L的组合消毒相比,采用加氯量4 mg/L的单一氯消毒的三氯甲烷生成量是前者的12倍左右。紫外-氯组合消毒方式可大幅度降低生态环境风险。

A test was conducted with collimated beam apparatus to inactivate Escherichia Coli of reclaimed water. The efficiencies of disinfection by UV - chlorine combination and single chlorine process were compared. The results showed that UV -chlorine combination process could reduce the dosage of chlorine than the single chlorine disinfection. Escherichia Coli could be inactivated completely under UV- chlorine combination process. When UV dosage increased from 3 to 5 mJ/cm2, the dosage of chlorine could be reduced to 1 mg/L. Following the increasing of UV dosage, the rate of chlorine dosage decrease became less under same inactivation condition. UV - chlorine combination process could reduce effectively the formation of THMs in reclaimed water compared with single chlorine disinfection. Under the requirement of complete inactivation of Escherichia Coli, compared with combination process with UV dosage of 10 mJ/cm2, chlorine dosage of 1 mg/L, the THMs formation was 12 times less than single chlorine disinfection with a dosage of 4 mg/L. Therefore, UV -chlorine combination process could significantly reduce the environmental risks.