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Biosparging consists of injecting pressurized air or gas into a contaminated zone in order to stimulate in situ aerobic biological activity. This remediation technique applies to dissolve and residual contamination in the saturated zone, and targets chemical compounds that can be biodegraded under aerobic conditions.
The injection of air (and gaseous nutrients if needed) favours the development of the aerobic microbial population by providing oxygen to the microbes and increases the interactions between air, water and aquifer, enhancing the bioavailability of the contaminants. The objective of a biosparging system is to promote contaminant biodegradation and to minimize the volatilization of volatile and semi-volatile organic compounds. The air injection flow rate is calculated to provide the quantity of oxygen required for enhancing bacterial degradation of contaminants. However, some volatilization may occur and depending on the chosen operation mode and design, air capture and treatment could be required.
Environmental Protection Agency 2016. Chapter VIII: Biosparging In How To Evaluate Alternative Cleanup Technologies For Underground Storage Tank Sites: A Guide For Corrective Action Plan Reviewers. EPA 510-B-16-005; U.S.A.
Environmental Protection Agency Clu-in, 2016. Bioremediation—Aerobic Bioremediation (Direct), December 5th 2016
4.32 Air Sparging—FRTR Remediation Technologies Screening Matrix and Reference Guide, Version 4.0
The injection method and the gas composition are two main possible variations in the biosparging system design. The gas injection can be performed using vertical or horizontal wells, and from trenches or reactive barriers. Nutrients are also introduced below the water table to enhance the microbial degradation activity to induce the destruction or transformation of contaminants of concern. The microbial population adapts to the new chemical and geochemical conditions. The treatment is stopped when contaminant concentrations reach treatment objectives.
Installation of individual air injection blowers or a central blower and distribution pipe system for an injection system
Tests examining the effect of temperature change on hydraulic conductivity and
establishing the zone of freezing with a pilot scale tubing system are recommended to
properly design the full-scale containment system.
In situ biosparging is potentially applicable to remote northern sites where impediments to material transport and injection equipment mobilization can be overcome. Cold temperatures can hamper biodegradation and microbial activity may only occur during the summer months, thus treatment time may take several years. Microbial activity may be possible in deep soil as temperatures (below permafrost) are relatively constant over the course of the year.
Chlorobenzenes: suitable for chlorobenzene, dichlorobenzene and trichlorobenzene.
Phenolic compounds: suitable for cresol, pentachlorophenol and tetrachlorophenol.
Non-metallic inorganic compounds: suitable for ammonia-nitrogen only.
Follow-up monitoring may be required to verify that the remediation objectives as well as applicable regulations are met once the groundwater system normalizes; after stimulation is withdrawn and excess biomass dies off.
Biodegradation of monocyclic aromatic hydrocarbons and petroleum hydrocarbons doesn’t usually generate any deleterious secondary by-products or metabolites. Issues with toxic intermediates may occur in the degradation of some explosives and pesticides.
Composed by : Magalie Turgeon, National Research Council
Updated by : Karine Drouin, M.Sc., National Research Council
Updated Date : April 1, 2009
Latest update provided by : Marianne Brien, P.Eng., Christian Gosselin, P.Eng., M.Eng., Golder Associés Ltée
Updated Date : March 22, 2019