Story

Confidential Client Northwest, USA

Summary

Adventus’ DARAMEND® technology was selected to remediate approximately 6,000 tons of soil impacted with pentachlorophenol (PCP) at a former chemical manufacturing facility located in the Northwest. Excavated soil was placed in a lined bioremediation cell in a 2 ft layer for treatment.

The Challenge

To reach a remedial goal of less than 50mg/kg in each soil sampling zone, containing approximately 175 tons each. The concentration of PCP in some sampling zones was as high as 2,000 mg/kg initially. This concentration would be considered by many as acutely toxic to most microbial populations, rendering the soil non-amenable to standard bioremediation practices.

The Solution

Following homogenization of the soil undergoing treatment, DARAMEND® was applied using a site-specific aerobic protocol that utilized indigenous micro organisms. The technology involved the addition of proprietary organic amendments and site-specific nutrient supplements designed to optimize the rate of microbial activity in the soil. The soil moisture content was then maintained at a relatively constant level (approximately 60% of the soil water holding capacity). The soil was tilled periodically to maintain an aerobic soil environment. Tilling was accomplished using a tractor mounted specialized deep rotary tiller with the capacity to till a depth of 2 ft.

The Result

PCP concentrations were reduced from as high as 2,000 mg/kg in some sampling zones to less than 30 mg/kg. The mean PCP concentration was reduced from 359 mg/kg to 16 mg/kg after approximately 8 months of treatment in 1999. The remedial goal of less than 50 mg/kg was met and surpassed in all sampling zones.

The Cost

The cost to apply DARAMEND® at this site was only $37/ton; however, a significant portion of the site work was conducted by the site owner.