三级串联式BCO反应器比耗氧速率及菌群结构分析

Analysis of specific oxygen consumption rate and microbial structure in a three-stage biological contact oxidation reactor

以厌氧/缺氧/好氧和生物接触氧化反应器(AAO-BCO)组成的双污泥系统为研究对象,研究了三级串联式生物接触氧化反应器(N1、N2、N3)中有机物浓度对比耗氧速率(SOUR)的影响,同时对比了各级处理单元的硝化特性。实验结果表明,N1、N2、N3分别在有机物浓度低于40、60和40 mg·L-1时,比耗氧速率随有机物浓度的升高而升高。根据比耗氧速率粗略估计了氨氧化细菌和亚硝酸盐氧化菌在各级中的百分比,其中氨氧化细菌的百分比分别为43.47%、54.94%和63.83%,而亚硝酸盐氧化菌的百分比分别为11.65%、21.87%和18.23%。由比耗氧速率计算得到氨氮比氧化速率和亚硝酸盐氮比氧化速率,其最高值分别为实际污水处理厂的1.9倍和1.2倍,生物接触氧化反应器中氨氧化细菌、亚硝酸盐氧化菌菌群更密集,硝化性能更优,且存在明显的亚硝酸盐累积现象(亚硝酸盐浓度为1.52~3.65 mg·L-1,亚硝态氮积累率最高可达25%)。

A two-sludge operation system consisting of anaerobic/anoxic/oxic and biological contact oxidation(AAO-BCO)reactors was used to study the influence of organic concentration on specific oxygen uptake rate(SOUR)in the three-stage biological contact oxidation(BCO)reactor(N1、N2、N3),and compare the nitrifying characteristics among these three units.The results showed that the SOUR increased with the increase of organic concentration when it in N1,N2 and N3 was lower than 40,60 and 40 mg·L-1,respectively.According to the SOUR data,the percentages of ammonia oxidizing bacteria in N1,N2 and N3 were roughly estimated to be 43.47%,54.94%and 63.83%,respectively.While the percentages of nitrite-oxidizing bacteria were roughly estimated to be 11.65%,21.87%and 18.23%,respectively.Additionally,the maximum values of specific oxidation rate of ammonia-nitrogen and specific oxidation rate of nitrite-nitrogen calculated through the SOUR data were 1.9 times and 1.2 times of those in actual wastewater treatment plants,respectively.The BCO reactor had more ammonia oxidizing bacteria and nitrite oxidizing bacteria and better nitrification performance,then the obvious nitrite accumulation phenomenon occurred with NO2--N concentration of 1.52~3.65 mg·L-1 and the maximum nitrite accumulation rate of 25%.