The effect of introducing the Dehalococcoides mccartyi strain UCH007, which completely dechlorinates chlorinated ethylenes, on bioremediation of trichlorethylene was evaluated in the batch culture experiment simulating aquifer contamination caused by convection-diffusion of pollutant from groundwater. The culture bottles were amended with sodium lactate in soil pore water and were cultured at 20℃ for 3 weeks. After confirming that the bottles were reached to an anaerobic sulfate-reducing condition, UCH007 was inoculated into the bottles. The groundwater concentration and soil elution amount of all chlorinated ethylenes including intermediates decreased below regulatory standards at 3 weeks after the inoculation of UCH007. UCH007 was present in the culture bottles at 0.1% proportion of total bacteria at the time of inoculation, but its number was maintained until the end of the remediation. It was shown that even a small number of UCH007 contributes to the rapid dechlorination of chlorinated ethylenes to harmless ethylene.

 This study aimed to feed zooplankton (Artemia spp.), which is widely used for seedling production of fishes for aquaculture, with microalgae cultivated in municipal wastewater treated with standard activated sludge process and chlorine disinfection. The microalgae cultivated in the treated wastewater without any supplements of nutrients was occupied (>95%) by class Chlorophyceae, among which species Chlorococcales was found most frequently. The microalgae was recovered from the treated wastewater after the cultivation, dried, ground and then used for the test of feeding larva of Artemia spp. for 10 days. For comparison, this zooplankton was also tested with a commercial feed and no feeding. In the feeding experiment, the population of Artemia spp. gradually decreased in all of the feeding conditions, probably due to environmental carrying capacity, inversely with the growing size of its body. The size of Artemia spp. fed by the microalgae for 10 days was 16% larger than those by the commercial feed and with no feeding. The microalgae feeding for 10 days could achieved a higher yield of Artemia spp. than the commercial feed probably because it has a high content of carbon and can supply purine required by the larva. These results revealed the availability of the microalgae originated from and cultivated in treated municipal wastewater as a feed for the larva of Artemia spp.

 Acidification of river water by an inflow of acidic spring had made it difficult to utilize the river water as domestic, industrial and irrigation waters. A large-scale neutralization work using a milk of lime has been conducted to improve water quality of the acidic river. The neutralization work must be continued to keep the improved river water quality. A novel electrochemical process for neutralization of the acidified river water was proposed in this study. The electrochemical experiments using the cell with the porous (molded activated carbon) electrode were carried out under the various operating conditions. In the continuous experiments using the acidified river water as feed solution, the solution in the cell was alkalified than a pH of 10 when the molded activated carbon was used as anode. The rate of pH rise was increased with the increment of the electric current and HRT (hydraulic retention time). On the other hand, in the continuous experiments using an alkaline solution, the solution in the cell was acidified than a pH of 4 when the molded activated carbon was used as cathode. The rate of pH drop was increased with the increase in applied current. In the control experiments using the stainless plate in place of the molded activated carbon, pH in the cell was slightly changed. From these results, it was considered that neutralization of the acidified river water could be attributable to the charge imbalance caused by the applied electrical field in which anions move toward the negatively charged porous anode. The electrochemical process proposed can be utilized for the neutralization of the acidified river water.

 CO₂ hydrate storage is considered as the second option in our Co., Ltd. of CO₂ underground storage in terms of carbon dioxide capture and storage for countermeasure against global warming. Since, CO₂ hydrate storage is controlled by both pressure and temperature, it is very important to know precisely the water depths where seawater temperatures are stable. Then about 1.75 million data around Japan is arranged in seawater temperature–pressure relationship and the relationships are formulated in this paper. The formulations would be used for the site selection of CO₂ hydrate storage.