From: Public Services and Procurement Canada
The in situ biopile is a remediation technology used for the treatment of contaminated surface soils (less than 4 meters from soil surface). This technology is only applicable in the unsaturated zone and is for the treatment of soils contaminated with organic compounds.
The in situ biopile technique consists of periodic mixing of the soil to improve oxygenation which enhances the aerobic biodegradation of petroleum hydrocarbons. During the mixing process, there can be volatilization of volatile and/or semi-volatile contaminants, although this is not the objective of the technology. The addition of fertilizers to stimulate microbial activity and/or the addition of agents to improve the soil structure and to control soil water content are also options. It is important to monitor and control the ammoniacal nitrogen concentration, potential of hydrogen (pH), and soil water content in the contaminated biopile to avoid a reduction or an inhibition of microbial activity. A monitoring system, including down gradient observation wells, must be integral to an in situ biopile system to ensure that no contamination is leaching toward the groundwater or other sensitive receptors.
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Notes:
Chlorobenzenes: suitable for chlorobenzene, dichlorobenzene and trichlorobenzene Phenolic compounds: suitable for cresol, pentachlorophenol and tetrachlorophenol Monocyclic Aromatic Hydrocarbons: applies with restrictions because these compounds are generally volatilized before being biodegraded.
Generally, biodegradation of petroleum hydrocarbons does not generate any deleterious secondary by-products or metabolites.
The treatment time required for site remediation with the in situ biopile varies according to the concentration and characteristics of the contaminants, the natural microbial populations, and the physical and chemical properties of the soil.
Composed by : Magalie Turgeon, National Research Council
Latest update provided by : Karine Drouin, M.Sc., National Research Council
Updated Date : April 1, 2008