折点加氯对微污染原水中氨氮去除效果的研究

Effects of break-point chlorination on ammonia nitrogen removal in micro-polluted raw water

对于微污染原水中氨氮含量较高的问题,目前很多水厂采用生物预处理的方式来降解水中的氨氮。但其生物作用受到气温、水温的影响,冬季低水温时生物作用的效果明显降低。在水温低于10℃时,生物预处理的效率下降更为显著,存在出厂水氨氮指标超国标要求的风险。通过对此进行研究,在水处理的末段消毒工艺中,有选择地采用折点加氯方式作为补充,通过化学作用,将出厂水中的氨氮转化为氮气,以达到去除效果。并在试验过程中对消毒副产物、生产成本、管理方式等进行了研究与探讨。

Many water treatment plants employ biological pretreatment to remove ammonia nitrogen from micro-polluted raw water with high ammonia nitrogen concentration. However, its performance would be affected by atmosphere temperature and water temperature; so, the biologi- cal treatment would be weakened in winter obviously. When the water temperature was below 10 ℃ the decrease of biological pre-treatment would be weakened especially and the ammonia nitrogen concentration in effluent might exceed the national standards. Comparison study showed that break-point chlorination would oxidize ammonia nitrogen into nitrogen at the end of water treatment process and reduce the ammonia nitrogen concentration in water. Some research on disinfection by-products, cost and management were also carried out.