枯水期出厂水余氯突降原因与对策

Reason ananlysis and regulation of sudden depletion of residual chlorine in finished water in dry season

针对江门市出厂水在枯水期出现余氯突降的现象,分析了出厂水余氯异常时出厂水及原水水质的变化情况、原水发生微污染时与河流潮汐的关系、原水氨氮和耗氧量的关系、原水氨氮和出厂水余氯的关系。结果表明,出厂水余氯出现突降是由于原水受到微污染造成的;氨氮、耗氧量以及河床水位可以作为原水微污染的预警指标,操作简单、有效;当预测到原水出现微污染时,采取加大和调整前后加氯量的方式,可解决由于原水微污染而引起的出厂水余氯突降的问题。

Aiming at the phenomenon of sudden depletion of residual chlorine in finished water in dry season of Jiangmen City,the variations of finished water and raw water under the condition of abnormal residual chlorine in finished water,the relation of micro-polluted raw water and river tide,the relation of ammonia nitrogen and oxygen consumption in raw water,and the relation of ammonia nitrogen in raw water and residual chlorine in finished water were analyzed. The result showed that the sudden depletion of residual chlorine in finished water was due to the micro-polluted raw water. Ammonia nitrogen,oxygen consumption and riverbed level could be the early warning indicators that were simple and effective. When the raw water was detected to be micro-polluted,the sudden depletion of residual chlorine in the finished water due to the micro-polluted raw water could be solved by increasing and regulating the dosage of prechlorination and postchlorination.