不同回流率下的循环流化床脱氮性能研究

NOVEL CIRCULATING FLUIDIZED BED BIOREACTOR FOR NITROGEN REMOVAL UNDER DIFFERENT NITRIFIED LIQUID RECIRCULATION RATES

一种新型的生物脱氮工艺——生物循环流化床（CFBBR）用于脱氮和除碳。系统由缺氧床（升流床）和好氧床（降流床）及其连接装置构成。进水由缺氧床底部进入，同来自好氧床的硝化液一起，在缺氧床内完成脱氮和除碳。研究了不同进水负荷，硝化液回流率200％～600％下的系统性能。从技术和经济角度考虑，400％硝化液回流率为最佳。最短水力停留时间2．5h（缺氧床0．8h，好氧床1、7h）和400％硝化液回流率下，TN和COD。。去除率和出水浓度分别为88％、95％和3．5mg／L、16mg／L。系统VSS低于1g／L，硝化率和反硝化率分别为0．026～0.1g／（g·d）和O．016～O．074g／（g·d）。

A new biological nitrogen removal process——The circulating fluidized bed bioreactor (CFBBR) is developed for simultaneous removal of nitrogen and organic matter. This system is composed of anaerobic bed, aerobic bed and connecting device. Influent and nitrified liquid from aerobic bed enter anaerobic bed from the bottom of the anaerobic bed, completing the removal of nitrogen and organic matter. The system performance under the conditions of different inflow loadings and nitrified liquid recirculation rates ranging from 200% to 600% was examined. From technical and economic point of view, the optimum nitrified liquid recycle rate is 400%. With a shortest total retention time of 2.5 h (0.8 h in the anaerobic bed and 1.7 h in the aerobic bed) and a nitrified liquid recirculation rate of 400% based on the influent flow rate, the average removal efficiencies and effluent concentrations of total nitrogen and soluble COD_ Cr are found to be 88%, 95% and 3.5 mg/L, 16 mg/L, respectively. The VSS concentration, nitrification rate and denitrification rate in the system are less than 1 g/L, 0.026 -0.1 g /(g·d) and 0.016～ 0.074 g/(g·d) respectively.