Nitrogen and Phosphorus Modification within a Petroleum Contaminated Biopile at the Oneida County Sanitary Landfill

Abstract

There are approximately 8,000 active Leaking Underground Storage Tank (LUST) cleanup sites in Wisconsin. With increasing active sites and decreasing state funds to help cleanup the sites, the issue of petroleum contaminated soil cleanup continues to be an important topic in the environmental field. There are many alternatives to cleaning up petroleum contaminated soil. This study will focus on a modernistic approach to petroleum contamination cleanup by utilizing units called biopiles. The study was conducted at the Oneida County Sanitary Landfill in Rhinelander, Wisconsin. A 230' long by 18' high by 95' wide (approximately the size of a football field) biopile was constructed using petroleum contaminated soil, slotted piping (for air input), nitrogen and phosphorus additions, a high density polyethylene cover, and tires to anchor the cover. The pipes were placed within the biopile for adding air to the soil to stimulate the growth of bacteria which breakdown the petroleum products into carbon dioxide and water. The cover on the pile was used to control air movement and soil water content. The biopile was in operation for approximately 11 weeks from August 14, 1997 to October 24, 1997. Within the pile, four sample plots were established. Plot A was used as a control (with no nutrient addition) while the remaining three plots had varying amounts of Nitrogen and Phosphorus added. Soil samples were collected on a bi-weekly basis and tested for Gasoline Range Organics, Carbon, Nitrogen, Phosphorus, pH, and moisture content. The results indicate that little or no biological activity occurred within any of the sample plots; hence, there was no or little biodegradation of the contaminants. It can be assumed that there were two main factors for the lack of degradation: I) less than optimal air circulation, and 2) excess moisture within the soil. Therefore, adding Nitrogen and Phosphorus to petroleum contaminated soil with the conditions present at the Oneida County Landfill did not increase biological activity or petroleum contaminant degradation.