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硝酸盐的原位反硝化系统。在该系统中，H_2作为电子供体，通过将电流传递给埋在含水层中的电极而产生。实验室规模的实验表明，在一年内可以实现稳定和完全的反硝化，而不会出现堵塞问题。即目前的原位反硝化工艺适合于处理贫营养条件下的污染地下水。为了提高脱氮率，研究了不同电极结构对脱氮效果的影响。反硝化速率受正极和负极平行于地下水流向的配置的影响，因为电解成分的极化增加了含水层的pH值。另一方面，建立了描述原位系统的数学模型，并与实验结果进行了比较。不同电流下的脱氮性能计算结果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，风能（或太阳能）发电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.