典型村镇水厂复合二氧化氯饮用水消毒效果及副产物调查

目的调查典型村镇水厂应用化学法复合二氧化氯发生器运行状况、消毒效果和消毒剂副产物状况,分析其影响因素。方法选择我国西南某地10座典型村镇水厂,采集水源水、出厂水和末梢水检测微生物指标、ClO_2和Cl_2余量、CHCl_3、CCl_4、ClO_3~-和ClO_2~-4种消毒副产物指标。采用描述性分析和相关性分析。结果出厂水ClO_2余量浓度范围为0.13~0.7 mg/L,Cl_2为0.07~0.74 mg/L,ClO_2余量指标全部符合GB 5749—2006《生活饮用水卫生标准》要求;出厂水ClO_3~-和ClO_2~-浓度范围分别为0.07~3.2和0.05~1.48 mg/L,超标率分别为60%和10%;调查的10台复合二氧化氯发生器中ClO_2/Cl_2指标合格的比例为70%,2台设备达到ClO_2转化率指标合格标准;不同品牌化学法复合二氧化氯发生器ClO_2转化率指标有显著差异(P0.05)。结论化学法复合二氧化氯发生器用于饮用水消毒时应优先关注的消毒副产物为ClO_3~-;ClO_2转化率低可能是消毒副产物ClO_3~-超标的主要因素。

Disinfection effects and disinfection byproducts investigation of complex chlorine dioxide generators for typical rural drinking water supply

Objective To investigate the operation status,disinfection effects,disinfection byproducts (DBPs) level and analyze the influencing factors.Methods Ten typical rural drinking water supplies were selected in southwest of China,raw water,outlet water and tap water samples were collected and microorganism,residue of ClO2 and Cl2,DBPs indexes including CHCl3,CCl4,ClO3-and ClO2-were determined.Descriptive analysis and correlative analysis were employed in data analysis.Results The concentration range of ClO2 and Cl2 residue in outlet water were 0.13-0.7 mg/L and 0.07-0.74 mg/L respectively,and ClO2 residue index for all outlet water samples met the national technical standard;The concentration range of ClO3-and ClO2-in outlet water samples were 0.07-3.2 and 0.05-1.48 mg/L respectively,the over standard rate were 60％ and 10％;70％(7/10) of the investigated generators were tested qualified based on the operation indicators of ratio of generated Cl02 and Cl2 (Cl02/Cl2),and two generators were evaluated qualified based on the indicator of yield of chlorine dioxide,which showed the ratio of generated amount of ClO2 divide by input amount of ClO3-.The operation indicator of yield of chlorine dioxide was significant different among equipments of different brand(P＜0.05).Conclusion ClO3-is one of the priority DBPs in drinking water while complex chlorine dioxide generator by chemical reaction is employed as the disinfection method.The lower yield of chlorine dioxide is the main influencing factor for exceeded ClO3-in water.