无污泥持留序批式反应器的脱氮理论模型

Model-Based Evaluation of Sequential Batch Reactor Without Biomass Retention

提出无污泥持留序批式反应器并建立其动力学理论模型.模型推导表明:反应器的脱氮效能是水力停留时间、曝气比率、进水周期等操作因子的函数;通过调控水力停留时间、曝气比率等因素,能调节反应器的好氧菌筛选因子和厌氧菌筛选因子,完成硝酸菌的洗出和反硝化菌的积累.模型极限分析表明现有Sharon反应器的实质是反应周期为零的无污泥持留序批式反应器.以荷兰Dokhaven污水处理厂的Sharon反应器为例,模型计算结果表明在水力停留时间为2.6 d、反应周期为2 h、曝气比率为0.175时,厌氧菌筛选因子值为0.020,低于反硝化菌的最大比生长速率0.034,好氧菌筛选因子值为0.093,介于亚硝酸菌最大比生长速率0.137与硝酸菌最大比生长速率0.082之间,此时反应器的理论氨转化率为98.9%,总氮脱除率为97.6%.

A new process （Without biomass retention Sequential Batch Reactor, WSBR） is proposed in which a SBR is operated without biomass retention in order to fulfill denitrification over nitrite, and then a mathematical kinetic model is established to describe nitrification and denitrification in this process. It is proved in the model that hydraulic retention time （HRT）, aerobic time ratio and batch cycle time are the factors which decide the minimal specific growth rate of the aerobic or anaerobic biomass remained in the reactor and then effect on the removal efficiency of NHn-N and TN. WSBR can screen out nitrite-oxidizing bacteria and accumulate denitrifying bacteria by optimal HRT or the aerobic time ratio. The limit of model shows that the existing Sharon processes were WSBR process virtually. A comparison was carried out between the model calculation and the practical data of the Sharon process in Dokhaven WWTP （Netherlands）. The result illuminates that the best parameters for denitrification over nitrite is HRT of 2.6 d, one cycle time of 2 h and the aerobic time ratio of 0. 173. Under these conditions, the minimal specific growth rate of the aerobic or anaerobic are 0. 093 and 0. 020 respectively, and the removal rate of NH4-N and TN can reach 98.9 % and 97.7 % respectively.