自来水生产中去除硝酸盐氮的研究

The Study on Removal of Nitrate Nitrogen in Processing of Tap Water

摘要: 地下水或自来水中硝酸盐、亚硝酸盐的去除是目前研究的热点和难点问题之一。本文对还原铁粉去除水中硝酸盐氮的方法进行了研究，探讨了反应时间、酸的滴加方式、pH值、铁粉添加量、搅拌转速等因素对硝酸盐氮去除效果的影响。结果表明：酸的滴加方式对硝酸盐氮的去除效果影响显著，反应过程中持续加酸比只在初始时调pH效果好，且维持初始pH越低，硝酸盐氮的去除效果越好；增大铁粉用量、提高反应时间均有利于硝酸盐氮的去除；搅拌器的转速对还原脱氮也有一定的影响，且随着转速的增加酸和铁的消耗也相应增加。其最佳工艺条件为：铁粉添加量为50 g/L，维持pH为4，搅拌速度为300 r/min，反应时间为45 min (其中前30 min持续加酸维持pH，后15 min不加酸)。

Abstract: At present, the removal of nitrate and nitrite in groundwater or tap water is one of the hot and dif-ficult problems. In this paper, the removal method of nitrate nitrogen by Zero Valent Iron is studied and the influencing factors on nitrate removal efficiency such as the reaction time, the add way of acid, the pH value, the additive amount of Zero Valent Iron and the stirring rate are discussed. The results show that the add way of acid significantly influences the effect on the removal of nitrate and nitrite. The mode of continuing to add acid during the reaction has a better effect than only adjust pH in the initial. The lower the initial pH value is, the better removal efficiency will be. Increasing of the amount of iron powder and the reaction time are beneficial to the removal of nitrate. In addition, the stirring rate also has certain influence on the removal of nitrogen. The consumption of acid and iron powder also increases when the stirring rate is high. The optimum process conditions are: 50 g/L Zero Valent Iron, pH = 4, stirring rate: 300 r/min, the reaction time: 45 min (The acid is continually added at initial 30 min to maintain pH value and is stopped in the latter 15 min).