Presented at the Maine Groundwater Conference March 16, 2011 in Augusta:

http://www.umaine.edu/waterresearch/mwc/sessions_11.html

Bio-pile siting, construction, operation, maintenance, and application on petroleum contaminated sites. Rangeley and Gardiner, Maine bio-pile examples.

Nicholas O. Sabatine, P.G., Erik P. Phenix, C.G., John K. Cressey, John B. Rand

Summit and Ransom Environmental Consultants, Inc. (Ransom), through the Maine Department of Environmental Protection (Maine DEP) Brownfields Program, have constructed bio-piles at sites in Gardiner and Rangeley, Maine. Bio-piles are a remediation alternative that can significantly reduce costs associated with petroleum contaminated soil management and disposal, while successfully reducing contaminant concentrations and allowing the soil to be made available for beneficial reuse options. Unlike traditional "land farming/land spreading" operations, the example bio-piles were designed to be self-sufficient. Through the augmentation of soil nutrients, active circulation of air, and optimization of ambient heat, petroleum hydrocarbons are degraded without the need for regular labor or mechanical maintenance.

Numerous factors, including siting constraints, contaminant characteristics and concentrations, soil chemistry, end use objectives, and mechanical and coordination logistics, need to be considered in the design and construction of a bio-pile. Each of these considerations will be discussed in relation to the example bio-piles, as well as suggestions and recommendations for future bio-pile projects.

The Rangeley bio-pile project will be presented as a case study in low-maintenance bio-pile remediation. The Rangeley project involved the evaluation of three separate bio-pile designs. One pile was used as a control, and received nutrient augmentation only. A second pile was designed with a re-circulating air system in addition to nutrient augmentation. The third pile included a solar collector connected to the re-circulating air system, along with nutrient augmentation. Findings from the Rangeley bio-pile project will be discussed in terms of temperature, nutrient depletion, microbial activity levels, length of treatment season, and percent reduction in contaminants.