Journal of Environmental Conservation Engineering

Show abstractHide abstract

Bio remediation is one of the ways to recover contaminated soils: it activates the microbes in soils and enhances bio-degradation processes by injecting air or nutrient solutions into contaminated soils. In this study, oil contaminated soils were remediated by injecting a nutrient solution into the soils. Effluent solution was analyzed and residual oil was extracted after the experiment in order to evaluate the remediation efficiency. Two injection rates, one using saturation and the other using unsaturation were tested to observe the saturation-induced differences in the flow regime. The resultant residual oil concentration showed that the unsaturated remediation process was more effective than saturation. This result is opposite to that of the in-situ application by the companies. The difference is most likely because dispersion was more dominant than convection, creating an effective distribution of the nutrient solution. In conclusion, the proposed remediation process and slow injection rate have advantages over the fast injection process because of its improved remediation results, lower cost and lower required nutrients, and reduced environmental impact due to lower groundwater leakage.

View full abstract

Download PDF (748K)

The decades-long changes and seasonal variations of water quality in the Kojima Lake, Sasagase River and Kurashiki River were investigated based on water quality observations at public access points. Each of these two rivers flows into the Kojima Lake. As a result, it becomes clear that the improvement of the lake water quality is statistically significant since the year 1995, and that water quality varies yearly at many observation points. In addition, the decades-long changes of the water quality were investigated, taking into account water purification countermeasure such as dredging of lake sediments and reduction of pollution load. comparing with the water purification countermeasure such as dredging of lake sediments and reduction of the pollution load.

View full abstract

Register with J-STAGE for free!