生物造粒流化床污水处理反应器中微生物的分布特征

对生物造粒流化床污水处理反应器10cm、60cm、110cm处好氧细菌总数以及反硝化菌、反硫化菌分别进行计数,同时,用光学显微镜、扫描电子显微镜以及石蜡切片技术对粒状污泥中细菌的分布情况进行研究。结果发现,流化床中好氧细菌非常丰富,在反应器10cm处,每克污泥微生物的数量可达1.6×10⁸个,说明好氧细菌在生物造粒流化床有机物生物降解中起主导作用;同时,流化床中也有一定数量的兼性厌氧菌存在,并且随着流化床床体的升高有增加的趋势,这与溶解氧(DO)随流化床床体高度的增加而迅速降低有关;随着回流比的增加,溶解氧增高,相应的好氧细菌有所增加而兼性厌氧菌减少;对于颗粒污泥,其表面和内部微生物分布数量有很大的差异。

Study on the characteristics of microorganisms distribution in a fluidized-pellet-bed bioreactor

In order to understand the distribution of microorganisms in fluidized-pellet-bed (FPB) bioreactor,bacteria enumeration in different heights (10cm,60cm and 110cm) of FPB was conducted respectively regarding total heterotrophic bacteria,denitrifying bacteria and sulfate-reducing bacteria. Microscopic,scanning electron microscopic (SEM),microbe fixation and embedding techniques were also applied. It was found that aerobic bacteria were dominant in both the bulk solution and pellets along the bed height,and the aerobic bacteria was about 1.6×10⁸ CFU·g^-1 sludge at 10cm height,It can be concluded that aerobic bacteria are playing the leading role of biological degradation in the FPB bioreactor. However,certain amount of anaerobic bacteria were found in the bioreactor and there was a tendency of increase of anaerobic bacteria in the upward direction,It was related to the rapid decreasing of dissolved oxygen (DO) along the bed height. As DO supply was enhanced by increasing the recycling flow ratio,the amount of the aerobic bacteria apparently increased while the amount of the anaerobic bacteria decreased. With single pellet particles,differences were noticed between the outer surface layer and inner cores in number of microbes.