回流比水力负荷对前置反硝化生物滤池工艺处理污水的影响研究

前置反硝化生物滤池工艺具有良好的脱氮性能,其中回流比是影响其处理效果的一个重要因素.试验考察了回流比分别为50%、100%、200%、300%的条件下该工艺对COD、NH4+-N、TN的去除效果.研究表明,在回流比从50%提高至300%的过程中,该工艺对污染物的去除效果以200%为界呈先上升后下降的趋势,但对去除TN的影响较为显著,回流比为200%时,对应COD、NH4+-N和TN的平均去除率分别为92.67%、90.50%和80.50%.在保持回流比100%的条件下,随水力负荷从1.52m.h-1增加到2.82m.h-1的过程中,前置反硝化生物滤池工艺对污染物的去除效果以2.08m.h-1为界呈先上升后下降的趋势,水力负荷为2.08m.h-1时,对COD、NH4+-N和TN的平均去除率分别为91.72%、90.29%和74.45%.COD、NH4+-N和TN主要在BAF(DN)缺氧环境内得到去除,平均去除率分别为78.48%、68.02%和58.21%.

Influence of reflux ratio and hydraulic loading on the performance of pre-denitrification BAF in wastewater treatment

Pre-denitrification BAF (biological aerated filter) performs well in denitrification of wastewater, and reflux ratio is one of the most important factors affecting the treatment performance. The removal effficiencies of COD, NH+4-N and TN were investigated seperately at reflux ratios of 50%, 100%, 200% and 300%. The results showed that the removal efficiency of contaminants for pre-denitrification BAF was increased initially, and then decreased when the reflux ratio was larger than 200%. However, the influence on TN removal was more significant than that for the removal of COD and NH+4-N. At the optimal reflux ratio of 200%, the average removal efficiencies of COD, NH+4-N and TN were 92.67%, 90.50% and 80.50%, respectively. Maintaining the reflux ratio at 100%, the removal efficiency of contaminants for pre-denitrification BAF initially increased, and then decreased at hydraulic loadings greater than 2.08 m·h-1. At the optimal hydraulic loading of 2.08 m·h-1, the average removal efficiencies of COD, NH+4-N and TN were 91.72%, 90.29% and 74.45%, respectively. It was also demonstrated that COD, NH+4-N and TN were removed mainly in the hypoxic environment in the BAF (DN), and the average removal efficiencies were 78.48%, 68.02% and 58.21% respectively.