内循环生物流化床反应器废水处理操作特性研究

Operating Performances of Three-phase Biological Fluidized Bed Reactor with Internal Circulation in Wastewater Treatment

通过生物流化床反应器处理合成废水实验,研究了冲击负荷和恒定负荷率下的COD和NH3-N去除率及进气量的影响。实验发现：当COD负荷率在3.5-11.2 kg COD/（m^3·d）区间阶梯式升高时,其去除率都能在短暂下降后迅速恢复到85%并保持稳定,表明内循环反应器具有良好的抗负荷冲击能力和操作弹性;对于不同浓度的进水,只要控制反应器有机负荷率OLR恒定,即可获得稳定的出水浓度;进气量对废水生化处理有双重影响,低气量时溶氧是控制因素,此时提高进气量,溶氧增加、生物膜活性增强,去除率随之增加,高气量时因溶氧饱和和生物膜受冲击损害,去除率不再增加甚至降低;本实验中对应最高去除率的进气量为125 L/h。

Treatment experiments of synthetic wastewater were carded out in a biological fluidized bed, reactor, to investigate the removal rates of COD and NH3 - N under different organic loading rates （OLR） and the effect of air flow - rate. It is found that with the COD loadings changed stepwise from 3.5 to 11.2 kg COD/（ m^3 · d） ,the removal rates of COD can rapidly restore to 85% or above from the impact of COD loading, showing that the reactor has a high flexibility for the variation of OLR in the intluent. Also, as long as the operating OLR keeps constant, the COD and NH3 - N concentrations in the effluent will keep nearly constant, although the concentrations of COD and NH3 - N in the iniluent are different. The flow - rare of air into the reactor has two respects of effect on the removal rates. As the flow - rate increases, the increased DO will strength the activity of bio -film ,leading to an increased removal rate, but excessive air supply will impact the bio - film and result in a decreased removal rate. In this work, the air flow rate related to the maximum removal rate is found to be 125 L/h.