低C/N城市污水亚硝酸型硝化试验研究

PARTIAL NITRIFICATION TO NITRITE IN URBAN WASTEWATER WITH LOW C/N

对低C/N城市污水进行亚硝酸型硝化的可行性、稳定性进行了研究,具体研究了系统的启动培养、稳定亚硝化、污泥毒害、短暂亚硝化、污泥适应等5个阶段及污泥的适应性问题。低C/N城市污水可实现稳定的亚硝酸型硝化,其亚硝化率最高可达90%。试验中合理确定反应周期的首要因素是系统出水NH4+-N的浓度至少达到50%降解率,其次是出水中NOx-NN应主要以NO2-N为主。根据泥龄维持所能维持的MLSS浓度确定系统泥龄在合理范围。系统不排泥和较长泥龄将不能通过排泥,将系统中硝化菌"洗出",硝化菌也会最终适应亚硝酸型硝化的环境因素,从而导致亚硝酸型硝化现象的不可逆消失。杆状污泥絮体为亚硝酸型硝化现象的特征污泥相。

This paper dealt with the feasibility and stability of partial nitrification to nitrite in urban wastewater with low C/N, in terms of start-up, stable partial nitrification, sludge poisoning, short partial nitrification and sludge adaptation. During the partial nitrification process, the stable nitrite accumulation can reach up to 90% in the urban wastewater with low C/N. The determination of reaction cycle required for NH4^＋-N degradation ratio with at least 50% and the NOx^-N in effluent dominated by NO2^-N. The sludge age of the system to a reasonable extent was determined by the concentrations of MLSS in relation to each SRT. In the case of the system unable to discard sludge or with long SRT, the nitrifying bacteria will not be “washed out” but eventually adapted to the partial nitrification circumstance to result in irreversible disappearance of partial nitrification. The sludge from partial nitrification is characterized by bacillary flocks.