液氯/二氧化氯联合消毒的消毒剂余量检测研究

Detection of Disinfectant Residual in Liquid Chlorine/Chlorine Dioxide Combined Disinfection Process

国内水厂多采用便携式仪器检测出水的游离氯及二氧化氯含量,在实际检测中,常常出现液氯消毒出水中检出二氧化氯,液氯/二氧化氯联合消毒出水的二氧化氯含量大于二氧化氯投量、游离氯含量偏高等问题。为此,基于GB/T 5750.11—2006中游离氯及二氧化氯的显色原理,分析了M水厂液氯/二氧化氯联合消毒生产试验中消毒剂余量数据异常的原因。通过现场试验发现,国标中用硫代乙酰胺消除背景干扰是不合理的,分析了水样背景显色物质的来源、优化了游离氯的测定方法。对于液氯/二氧化氯联合消毒,在缺少国标规定的条件下,给出了现场测定游离氯及二氧化氯的推荐方法。

Portable instruments are widely used in detection of free chlorine and chlorine dioxide in domestic waterworks. In actual detection, many problems occurred, for example, chlorine dioxide is detected in chlorine disinfection water, effluent chlorine dioxide content is greater than the chlorine diox- ide dosage and free chlorine content is high in liquid chlorine/chlorine dioxide combined disinfection process. Therefore, reasons for abnormal dates of disinfectant residual in liquid chlorine/chlorine dioxide combined disinfection production experiment in M waterworks were analyzed, based on the coloration principle of free chlorine and chlorine dioxide in GB/T 5750.11 - 2006. It was found that it was unrea- sonable to use thioacetamide to eliminate background interference in national standard. Meanwhile, the source of colorant in water sample background was analyzed and the determination method of free chlorine was optimized. For the liquid chlorine/chlorine dioxide disinfection, a recommended method for field de- termination of free chlorine and chlorine dioxide was proposed in the absence of national standard regula- tions.