稻草强化生物膜浮床脱除工业尾水中氮素及COD的效果

工业污水处理厂排放的尾水中总氮含量偏高,容易引起地表水体的富营养化。为了提高尾水中总氮的去除效率,通过模拟稳定塘静态和动态试验,对比了不同稻草添加量(0,0.18,0.54 g/L)强化生物膜浮床脱除工业尾水中总氮(TN)的效果。静态试验结果表明:随着稻草量的增加,TN的去除率显著提高;10 d后,添加0(CK)、0.18 g/L(T1)和0.54 g/L(T2)稻草的尾水中,TN去除率分别为18%,40%,93%。动态试验结果显示,水力停留时间(HRT)为 4 d时,CK、T1和T2的平均TN去除率分别为10%,22%,49%,且3种情况下的进出水COD浓度无显著差异。这主要是由于稻草通过缓慢释放碳源为生物膜中异养反硝化细菌提供可利用的有机物。研究成果可为工业尾水深度处理脱氮技术提供参考。

Removal of Total Nitrogen and COD from Industrial Tail Water by Biofilm Floating Bed Strengthened with Rice Straw

Large content of total nitrogen (TN) in the tail water discharged from industrial wastewater treatment plant is likely to cause eutrophication in surface water. In order to improve the removal efficiency of TN in the tail water, we investigated into the removal rate of TN by biofilm floating bed strengthened with different amounts of rice straw (0, 0.18 g/L, and 0.54 g/L) by simulated static and dynamic stabilization pond experiment. Static experiment result showed that the removal rate of TN increased significantly along with the increment of rice straw amount; after 10 days, the removal rate of TN was respectively 18%, 40%, and 93% when 0 (CK), 0.18 g/L (T1), and 0.54 g/L (T2) rice straw were added into the floating bed. Dynamic experiment result revealed that the mean TN removal rate of CK, T1 and T2 was respectively 10%, 22%, and 49% when the hydraulic retention time (HRT) was 4 d; no significant difference was found in COD concentration in the influent and effluent under the three conditions due to the fact that rice straw provides organic matter for heterotrophic denitrifying bacteria in biofilms by slowly releasing carbon source.