Development of a H_2 utilizing In-situ denitrification system used for nitrate-contaminated groundwater.

提出了一种新型的浅层地下水原位反硝化系统。在该系统中，H_2被用作电子供体，其通过将电流传递到嵌入含水层中的电极而从水中产生。小试结果表明，该工艺可以在一年多的时间内实现稳定、完全的反硝化，且无堵塞问题。为提高反硝化速率，研究了电极结构对反硝化效果的影响。反硝化速率的影响，特别是当阳极和阴极平行于地下水流动方向安装的配置，因为在含水层的pH值增加的电解成分的极化。另一方面，开发了描述原位系统的数学模型，并与实验结果进行了比较。在不同电流下计算的脱氮性能与实验结果非常接近。最后，通过三个案例研究探讨了利用自然风能和太阳能的可能性。在日本的一些地区，与风力（或太阳能）发电相结合的原位系统被认为是可行的。

A novel in-situ denitrification systemis proposed for treating nitrate in groundwater in shallow aquifers. In the system, H_2 is used as an electron donor which is produced from water by passing electric current to electrodes embedded in aquifer. Laborratory-scale experiments showed that stable and complete denitrification could be achieved over one year without clogging problem. That is, the Present in-situ denitrification process is suitable for treating polluted groundwater under oligotrophic conditions.To enhance the denitrification rate, the effect of the electrode configurations was investigated. The denitrification rates were affected by the configuration especially when the anode and cathode were installed parallel to the groundwater flow direction because pH in the aquifer was increased by the polarization of electrolytic constituents. On the other hand, a mathematical model describing the in-situ system is developed and compared with the experimental results. The denitrification performances calculated at different electric currents were very similar to experimental results. Finally, apossibility of utilizing natural wind and solar energies were investigated in three case studies. A combined in-situ system with wind (or solar) Power generation is considered feasible in some area in Japan.