DN/CN强化脱氮技术在污水厂提标改造中的应用

以某市城镇污水处理厂NO3--N浓度较高的生化出水为研究对象,采用反硝化生物滤池+曝气生物滤池(DN/CN)工艺,研究了碳氮比(C/N值)、进水负荷、温度等对TN去除效果的影响。结果表明,当增加的C/N值为3.6、水力负荷≤9.44 m^3/(m^2·h)[NO3--N最大负荷为4.8 kg/(m^3·d)]时,出水TN满足国标要求(≤10 mg/L);去除单位质量TN需3.7倍COD,碳源不足会导致NO2--N积累和碳源单耗升高;14℃时的TN去除率较19℃时下降了约15%;反硝化过程中pH值增量和TN去除量存在一个对应关系,可用于反硝化滤池处理效果的辅助判断。

Application of DN/CN Enhanced Nitrogen Removal Technology in Upgrading and Reconstruction of Wastewater Treatment Plant

The effluent contained high nitrate concentration of a bioreactor in a municipal wastewater treatment plant was treated by a process of denitrification and nitrification biofilters(DN/CN),the effects of carbon to nitrogen(C/N)ratio,influent load and temperature on total nitrogen removal were investigated.When C/N ratio increased by 3.6 and hydraulic load was no more than 9.44 m^3/(m^2·h)[the maximum nitrate load was 4.8 kg/(m^3·d)],the effluent TN met the national standard requirements(≤10 mg/L).Removing per unit mass TN required 3.7 times COD,and insufficient carbon source would lead to accumulation of nitrite and increase of carbon source per unit consumption.TN removal efficiency at 14℃decreased by about 15%compared with that at 19℃.A corresponding relationship between pH increment and TN removal amount was developed,which could be used to assist in estimating the treatment efficiency of the denitrification filter.