Bio-Gel/Bio-Water Remediation of Contaminated Soil Summary and conclusionsAn in situ biological remediation of a 1500 sq.m large oil polluted area has been carried out. The area was contaminated with light fuel oil from one to about four meters of depth. In order to enhance the biological processes, the area was treated with Bio-Gel and Bio-Water injected via high pressure pipes and via horizontal, perforated pipes, drilled through the polluted strata. Analyses of the concentration of the contaminants were carried out before the start of the injection and during the remediation period. Furthermore, analyses of the contaminant concentration in the pore water and the groundwater were carried out. Analyses of soil and vapour samples were also conducted to identify evidence of biological degradation of the contamination. The results of the monitoring program show no reduction of contaminant concentration in the soil. In addition, no signs of increased biological activity in the contaminated area could be identified as a result of the injection of Bio-Gel. Finally, it has not been possible to detect the species of bacteria in either the Bio-Gel or in soil samples in the treated area. During the first months of the treatment period, vague indications of leaching of the oil were observed. These indications were increasing oil concentrations in the pore water and the groundwater. During the last months of the period these indications were no longer present. The collected data indicate that only minor amounts of oil have leached from the site. The results of the monitoring gives rise to the following recommendations: Before the use of additives for the enhancement of biological degradation of oil contamination in soil, laboratory treatability tests shall be performed, in order to investigate whether it is physically possible to penetrate the soil with the additive, and whether the additive will enhance the biological degradation of the contaminants. At the start of the project it was expected that laboratory tests of the additives would be carried out to confirm the ability of the product to degrade oil pollution. These tests were, however, not conducted, for which reason no conclusions on this issue can be drawn..
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