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

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

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%.

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.