城市污水生化处理工艺参数优化实验研究

Experimental Study on Optimization of Process Parameters for Biochemical Treatment of Urban Wastewater

为了提高A^(2)/O生化处理法对城市污水的处理效率,以目标城市污水为研究对象,开展了A^(2)/O生化处理工艺参数优化实验研究,主要考察了水力停留时间、污泥龄、混合液回流比和实验温度对城市污水生化处理效果的影响。结果表明:水力停留时间越长、污泥龄和混合液回流比越大、实验温度越高,A^(2)/O生化处理工艺处理后的城市污水中COD、TN、氨氮和TP浓度值则越低。推荐适合目标城市污水A^(2)/O生化处理工艺的最佳参数为:水力停留时间为5 h,污泥龄为10d,混合液回流比为200%,实验温度为20℃。经过A^(2)/O生化处理工艺处理后的城市污水中COD、TN、氨氮和TP质量浓度值分别可以降低至31.68mg·L^(-1)、7.58mg·L^(-1)、3.04 mg·L^(-1)和0.41 mg·L^(-1),均能满足国家标准GB18918—2002中规定的一级A标准排放的要求。

In order to improve the treatment efficiency of A^(2)/O biochemical treatment method for urban sewage,an experimental study was conducted on the optimization of A^(2)/O biochemical treatment process parameters with the target urban sewage as the research object.The main factors affecting the biochemical treatment efficiency of urban sewage were investigated,including hydraulic retention time,sludge age,mixed liquid reflux ratio,and experimental temperature.The experimental results showed that the longer the hydraulic retention time,the larger the sludge age and mixed liquid reflux ratio,and the higher the experimental temperature,the lower the mass concentration values of COD,TN,ammonia nitrogen,and TP in urban sewage treated by A^(2)/O biochemical treatment process.The recommended optimal parameters for the A^(2)/O biochemical treatment process of urban sewage in the target city were as follows:hydraulic retention time 5 h,sludge age 10 d,mixed liquid reflux ratio 200%,experimental temperature 20℃.The mass concentration values of COD,TN,ammonia nitrogen,and TP in urban sewage treated by the A^(2)/O biochemical treatment process were reduced to 31.68 mg·L^(-1),7.58mg·L^(-1),3.04 mg·L^(-1)and 0.41 mg·L^(-1),respectively,which couldmeet the discharge requirements of the first level A standard specified in the national standard GB18918—2002.