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

提出了一种处理浅层地下水中硝酸盐的新型原位反硝化系统。在该系统中，氢气作为电子供体，通过将电流传递到埋在含水层中的电极来从水中产生电子。小试试验表明，在一年以上的时间内，可以实现稳定、彻底的反硝化，不会出现堵塞问题。为提高反硝化效率，考察了电极配置对反硝化效果的影响。构型对反硝化速率的影响较大，尤其是当阳极和阴极平行于地下水流向时，因为电解液成分的极化提高了含水层中的pH。另一方面，建立了描述原位体系的数学模型，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，通过三个案例研究了利用自然风能和太阳能的可行性。在日本的一些地区，风力(或太阳能)发电与就地发电相结合的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.