Assessing the Performance of In Situ Soil Enhancement Technologies to Improve Ground Water Quality

University of Aberdeen School of Biological and Soil Sciences, Cruickshank Building,
St. Machar Drive, Aberdeen AB24 3UU, August 2004

Manufactured gas plants (MGP) produce different contaminants that when released into the environment cause significant soil and ground water pollution. In situ enhanced bioremediation techniques are effective in remediation of MGPs particularly for contaminants such as the dense non-aqueous phase liquids (DNAPL). Coal tar is a DNAPL and soil particles affect the hydraulic conductivity of these compounds and microbial activities.

The aim of this study was to assess the potential of in situ technologies in a laboratory column experiment. In situ amendments of nitrogen, phosphorus and oxygen releasing compound were performed on site. Soil samples were collected from a site and leached daily to equate a 20 years cycle. The biosensor Escherichia coli HB101 was used to assess the toxicity of soil leachate while standard chemical analysis was performed. The result of this study suggests that the presence of tar in the soil resulted in an increase in retention time of leachate and water chemistry over time. Nutrients release in the soil leachate was very low which reflected slow in situ biodegradation of the contaminants.