Composting of soils contaminated with heavy petroleum hydrocarbons.

Abstract

This project tested at the field scale, five on-site, non-proprietary bioremediation processes on weathered petroleum hydrocarbons from a fire fighter training area. Two bioremediation processes based on fungi (commercially produced white rot fungus, Pleurotus ostreatus, and aged, coarse wood chips, 'compost', with naturally occurring fungi) were applied with variations and compared to one control: a typical static biopile. An elevated-face compost turner was used to turn the soil in selected windrows for aeration. Statistically-based sampling was employed and quality control measures were enforced for sampling and analysis. The treatment options examined for the contaminated soil were: (1) white rot fungus and compost, (2) compost, poultry manure and turning, (3) compost, synthetic nitrogen-phosphorous-potassium fertilizer, and turning, (4) compost, the above synthetic fertilizer, and no turning, and (5) the above synthetic fertilizer, and no turning (static biopile). The compost and poultry manure process performed the best, remediating 35 tonnes of soil contaminated with 6000 mg/kg of mineral oil and grease (MOG) to the remediation criteria of 1000 mg/kg in 19 days and to less than 300 mg/kg in less than 56 days. The net rate of bioremediation was 100 mg/kg/day of MOG. The estimated cost of this process for commercial applications, excluding labour, excavation and site preparation, was $18 to $29 per tonne, depending on the cost of the poultry manure.