Development of a simple nitrate removal reactor using biofilm-electrode.

基于生物膜数学模型，首次对生物膜-电极系统的反硝化速率进行了分析。该模型考虑了电场中的传质速率、生物反应速率和电化学反应速率。模型计算结果表明，反硝化速率对外加电流的响应可分为三个区域：线性区域和下降区域。从工艺设计和控制以及实验室规模反应器的长期性能的观点来看，生物膜电极系统可以在线性区域中操作。另一方面，开发了一种新型的金属电极多极电极系统，用于强化反硝化，并设计和构建了多生物膜电极反应器（MultiBER）。Multi BER的连续实验表明，通过施加电流，地下水中的硝酸盐被稳定而快速地去除，同时处理后的水被阳极产生的氧气曝气。同时，BER对硝酸盐和农药的去除效果较好，而对SO_4 ~（2<2->-）、Cl ~（2-）和Ca ~（2+）的去除效果较好。

Denitrification rates of a biofilm-electrode system were first analyzed based on a mathematical biofilm model. The model takes into cinsideration the mass transfer rates in the electric field, biological reaction rates, and electrochemical reaction rates. Calculation results from the model showed that the response of the denitrification rates to applied electric current can be divided into three regions ; linear, and declined regions. From a view point of process design and control as well as a long term performance of laboratory-scale reactors, the biofilm-electrode system can be operated in the linear region. On the other hand, a novel multi-polar electrode system using metal electrodes was developed for enhanced denitrification and a multi biofilm electrodes reactor (Multi BER) was designed and constructed. Continuous experiments with the Multi BER demonstrated that nitrate in groundwater was stably and quickly removed by an application of electric current and at the same time the treated water was aerated by oxygen produced from anode. Furthermore, it was also demonstrated that nitrate and pesticide were removed concurrently by BER but other major constituents such as SO_4^<2->, Cl^-, and Ca^<2+> were almost the same in the influent and effluent.