次氯酸钠与液氯消毒效果及消毒副产物对比分析

Comparative Analysis of Disinfection Effect and Disinfection By-products of Sodium Hypochlorite and Liquid Chlorine

目的研究水厂消毒方式由液氯转变为次氯酸钠后对出厂水消毒效果与消毒副产物的影响。方法采集6家水厂转变消毒方式前后出厂水水样共22份,检测消毒效果与13种消毒副产物的指标水平。结果两种消毒方式出厂水消毒效果与13项消毒副产物指标均合格;次氯酸钠消毒出厂水中游离余氯、一氯二溴甲烷、二氯一溴甲烷、三溴甲烷、三卤甲烷、三氯乙醛的浓度均高于液氯消毒,差异具有统计学意义(P<0.05);出厂水游离余氯浓度≥1 mg/L时,消毒副产物中的一氯二溴甲烷、二氯一溴甲烷、三溴甲烷、三卤甲烷、三氯乙醛浓度均比游离余氯浓度水平<1 mg/L时升高,差异均具有统计学意义(P<0.05)。连续1个月测定有效氯含量均为10%的次氯酸钠消毒剂,32℃保存条件下有效氯含量为原含量的67.40%,4℃保存条件下有效氯含量为原含量的89.51%。结论两种消毒方式均具有较好的消毒效果,部分消毒副产物指标差异受到消毒剂种类、有效氯含量的影响。

Objective To explore the effect of water disinfection and disinfection by-products after exchanging of disinfection reagents from liquid chlorine to sodium hypochlorite.Methods A total of 22 water samples were collected from 6 water plants before and after exchanging disinfection reagents;the disinfection effect and the concentrations of 13 disinfection by-products were detected.Results The disinfection effect of the two disinfection reagents and that of 13 disinfection by-products were all qualified;the concentrations of free residual chlorine,dichlorodibromomethane,dichloro-1-bromomethane,tribromomethane,trihalomethane and trichloroacetaldehyde in the factory water disinfected by sodium hypochlorite were higher than those by liquid chlorine disinfection,for which the differences were statistically significant(P<0.05);when the concentration of free residual chlorine in the factory water was more than or equal to 1 mg/L,the concentrations of dichlorodibromomethane,dichloro bromomethane,tribromomethane,trihalomethane and trichloroacetaldehyde in the water were higher than those in factory water,in which the concentration of free residual chlorine was<1 mg/L,and the differences were statistically significant(P<0.05).The 10%available chlorine content for sodium hypochlorite decreased to 67.40%of the original content at 32℃and 89.51%of the original content at 4℃disinfectant when the 10%available chlorine content in sodium hypochlorite stored for one month.Conclusions Though sodium hypochlorite and liquid chlorine have good disinfection effect,the contents of some disinfection by-products is effected by the types of disinfectant and the content of available chlorine in disinfactants.