生物膜生态浮床对城市尾水净化特征分析

Purification Characteristics of Urban Tail Water from Sewage Treatment Plant by Biofilm Ecological Floating Bed

为探究生物膜对城市尾水的净化特征,通过采用联合生物膜生态浮床技术,考察生物膜长度、水力停留时间(HRT)及生物膜覆盖面积对含氮尾水的净化特征.结果表明,生物膜为1/2水深长度时,NH4^+-N、NO3^--N和TN的去除率分别可达到90.82%、62.7%和81.96%,氮去除率较高,而生物膜长度为整个河道水深时,NH4^+-N的去除率最高只有22.07%,NO3^--N和TN的浓度变化不明显.在HRT为6 d时,NH4^+-N和TN的去除率最高分别可达到82.01%和62.88%,最低分别为55.24%和46.82%;当HRT为12 d时,NH4^+-N和TN的去除率最高分别可达81.4%和79.93%,但最低分别达到了8.73%和17.23%,对比发现,HRT为6 d时氮的去除效率较高且稳定.在生物膜覆盖面积为10%时,一个运行周期内NH4^+-N去除率呈下降趋势,而覆盖面积为20%时,去除率呈上升趋势;TN在10%和20%的膜覆盖面积条件下去除率分别为62.88%和71.09%.

The purification characteristics of nitrogenous tail water were investigated using a biofilm ecological floating bed technology to study biofilm length,hydraulic retention time(HRT),and biofilm coverage area with the aim to explore the purification characteristics of biofilm on urban tail water.Results show that the removal rates of NH4^+-N,NO3^--N,and TN were 90.82%,62.7%,and 81.96%,respectively,at the half water depth to the suspended biofilm.The removal rate of NH4^+-N was only 22.07%,and the concentration changes of NO3^--N and TN were not obvious throughout the whole water depth to the suspended biofilm.When the HRT was 6 days,the removal rates of NH4^+-N and TN could reach 82.01%and 62.88%,respectively,whereas the lowest rates were 55.24%and 46.82%,respectively.When the HRT was 12 days,the removal rates of NH4^+-N and TN reached up to 81.4%and 79.93%,respectively,whereas the lowest rates were 8.73%and 17.23%,respectively.In contrast,the nitrogen removal efficiency was high and stable when the HRT was 6 days.When the coverage area was 10%,the removal rate was decreased in one operation cycle.When the coverage area was 20%,the removal rate showed an upward trend.Under the conditions of 10%and 20%biofilm coverage area,the removal rates of TN were 62.88%and 71.09%,respectively.