四种方法对医院污水中总余氯测试的比对试验

目的观察四种测定方法对医院污水总余氯量测定的差异,确定较准确方便的方法。方法分别采用DPD滴定法、碘量法和两种比色法,对含氯消毒剂处理后的医院污水进行了比对试验。结果20份医院污水的检测结果比较,DPD滴定法测得医院污水总余氯量比碘量法测定结果高出60%,二者之间有显著性差异。HANNA余氯比色计与申水牌余氯比色计测定结果之间无明显差异,但其测得总余氯量比化学滴定法低约10倍。模拟回收试验中,DPD滴定法测得余氯回收率平均比碘量法约高40%,碘量法测定结果接近理论值,两种比色法测定余氯回收率较低。结论医院污水总余氯4种测定方法测定值存在明显差异,碘量法测定结果接近理论值,两种比色法测定结果偏低。

COMPARATIVE EXPERIMENT ON FOUR METHODS FOR DETECTING TOTAL RESIDUAL CHLORINE IN HOSPITAL SEWAGE

Objective To determine a relatively accurate and convenient method for detecting total residual chlorine in hospital sewage by comparing four different methods.Methods DPD titration,iodometry and colorimetry using two kinds of colorimeter were used to carry out comparative measurement of total residual chlorine in hospital sewage treated by chlorine-containing disinfectant.Results By comparing the results of 20 samples of hospital sewage,the total residual chlorine measured by DPD titration was 60% higher than that measured by iodometry,suggesting that there was significant difference between the two methods,whereas the results obtained by two kinds of colorimeter named HANNA and SHEN SHUI had no obvious difference and were nearly a tenth of the result obtained by DPD titration.Simulating recovery experiment showed that on average the recovery rate of residual chlorine detected by DPD titration was 40% higher than the result obtained by iodometry which was close to the theoretical value,and the results obtained by colorimetry using two kinds of colorimeter were lower.Conclusion There were significant differences in total residual chlorine in hospital sewage detected by 4 methods.The result obtained by iodometry was close to the theoretical value,while the results detected by colorimetry using two kinds of colorimeter were lower.