||IT Environmental Programs, Inc., Cincinnati, OH. ;ECOVA Corp., Redmond, WA.;Environmental Protection Agency, Cincinnati, OH. Risk Reduction Engineering Lab.
A pilot-scale test of the slurry-phase bioremediation technology was performed by ECOVA Corporation (ECOVA) at the U.S. EPA Test and Evaluation (T&E) facility from May 8 through July 10, 1991 (12 weeks). The slurry-phase bioreactors were tested on a creosote-contaminated soil from the Burlington Northern Superfund Site in Brainerd, Minnesota. The results of the bench-scale study (performed by ECOVA prior to the pilot-scale study) were used to optimize a pilot-scale bioreactor system containing 64 liters of 30 percent slurry (soil:water, w/v). The pilot-scale phase utilized an inoculum of indigenous polynuclear aromatic hydrocarbon (PAH) degraders (9.3 x 10 to the 7th power per gram of soil), an inorganic nitrogen supplement in the form of NH(4-)N, and a media broth containing potassium, phosphate, magnesium, calcium, and iron to achieve an overall reduction. During the study, levels of soil-bound and liquid-phase PAHs, total petroleum hydrocarbons (TPHs), nutrients, pH, dissolved oxygen, temperature, toxicity, and microbial activity were monitored.