Development of a continuous single tank nitrification-denitrification process

针对传统脱氮工艺存在的问题，开发了单池连续硝化反硝化工艺。将拉管式反应器应用于污水处理，并对该反应器的运行参数和设计参数进行了考察。从实验和理论上建立了导流管式反应器内循环流速和K_La的经验公式。在此基础上，对污水进行了连续处理。结果表明，该反应器对TN的去除效率可达70-75%。研究还发现，要获得80%以上的硝化和反硝化效果，好氧带比和缺氧带比都必须保持在0.35以上。进水C/N应控制在3左右(mg C/mgN)。导流管直径与反应器直径之比(D_1/D_0)影响TN的去除效果。在有效深度为4m的反应器中，只有当D_1/D_0为0.19时，TN才能被去除70%以上。环空部分的DO下降率分析表明，反应器的有效深度越大，越容易形成好氧和缺氧区。利用数学模型对尾管式反应器脱氮的运行参数和设计参数进行了深入的考察，建立了免疫分析法选择性测定混合液中好氧反硝化菌的方法。数学模型检验表明，随着BODMLSS负荷率的增加，混合液中好氧反硝化菌的比例增加。

Continuous single tank nitrification-denitrification process was developed to overcome the lssues pointed out in the conventional nitrogen removal processes. Drafttube type reactor was applied to sewage treatment and operational and design parameters of this reactor were examined. Ability of aerobic denitrifier is utilized was also examined.Empirical equations on velocity of circulating flow and K_La in the draft-tube type reactor are constructed both experimentally and theoretically. Based on the results, continuous sewage treatment was performed. The results showed that 70-75% TN removal efficiency can be obtained in this reactor. It was also found that both aerobic zone ratio and anoxic zone ratio are necessary to be kept more than 0.35 to obtain more than 80% of both nitrification and denitrification ratio. C / N ratio in the influent is necessary to be kept about 3 (mg C / mgN). The ratio of draft tube diameter to reactor diameter (D_1 / D_0) influences TN removal efficiency. In the reactor which has effective depth of 4m, more than 70% TN can be removed only when D_1 / D_0 is 0.19. Analysis of DO decreasing rate in the annulus part shows that the higher effective depth of the reactor is, the easier both aerobic and anoxic zone can be created. Operational and designed parameters for nitrogen removal in the draft tube type reactor were examined extnsively by using the mathematical model.A selective determination method of the aerobic denitrifier in the mixed liquor is developed with immuno assay. Examination by using the mathematical model shows that the ratio of aerobic denitrifier increased in the mixed liquor by increasing BODMLSS loading rate.