城市污水厂氯消毒出水脱氯特性研究

研究了亚硫酸钠、亚硫酸氢钠、二氧化硫、焦亚硫酸钠和硫代硫酸钠等脱氯剂对城市污水厂氯消毒出水的脱氯效果.结果表明:亚硫酸氢钠的脱氯效果最好,反应10 min,氯脱除率即达100%;脱氯过程均存在分步反应,反应最初1 min内,余氯下降很快;1 min后为一级反应,且反应速率很低,有机氯胺和一氯胺的脱除是反应的限制因素.脱氯反应不会对最终出水的细菌和大肠杆菌指标产生不利影响.经济分析表明,达到同样的脱氯效果,二氧化硫脱氯工艺的药剂成本最低.

Comparison of various reducing reagents in dechlorination of chlorinated secondary effluent

Chlorine removal efficiencies of sodium sulfine,sodium bisulfite,sulfur dioxide,sodium metabisulfite and sodium thiosulfate were studied.The results showed that,Dechlorination performance of sodium hydrogen sulfite was best.At 10 min reaction time,rate of dechlorination was 100%.All reactions were found to be step-wise.During the initial 1 min of the reaction,there was a sharp drop in residual chlorine concentration.Thereafter,the reduction of residual chorine followed first-order and the reaction rate was rather low.Thus combined chlorine was the limiting factor in the dechlorination.Moreover,the microbiological parameters,such as the numbers of coliform and bacteria,almost remained the same during the dechlorination.To achieve the same dechlorination performance,sulfur dioxide required the lowest chemical cost.