InSitu Remediation Services Limited (IRSL) services

Harnessing powerful oxidizing compounds to chemically reduce impacts in place. Chemical oxidation involves the transfer of electrons from one compound to another. Oxidizing compounds (i.e. oxidants) accept electrons from reduced species such as organic carbon-based compounds. When designed correctly, and completed in the subsurface (i.e. in situ), this reaction results in the transformation of contaminants into harmless compounds.

Harnessing powerful reducing compounds to chemically mitigate impacts in place. The other half of a redox reaction, chemical reduction results in the gain of electrons. One of the reactants in the reaction is oxidized, losing electrons; the other reactant is reduced, gaining electrons. In In-Situ Chemical Reduction (ISCR), reducing compounds—compounds that accept electrons given by other compounds in a reaction—are injected into the subsurface to transform contaminants into harmless compounds.

Enhancing natural, organic processes to affect green remediation. With sufficient oxygen (aerobic conditions) and other nutrients, microorganisms will use many organic contaminants as a food source, effectively breaking them down into carbon dioxide, water, and microbial cell mass.

Enhancing natural, organic processes to affect green remediation. In the absence of oxygen (anaerobic conditions), anaerobic microorganisms will use many organic contaminants as a food source, effectively breaking them down into carbon dioxide, water, and microbial cell mass.

Mobilizing contaminants for efficient extraction. Cosolvent flushing involves injecting a solvent mixture, such as water with alcohol, into an aquifer impacted with Non-Aqueous Phase Liquids (NAPLs) to solubilize and increase the mobility of the compounds. The solvent and the solubilized NAPL are then removed through extraction wells, and either treated on-site or disposed of off-site. The cosolvent mixture is typically injected up-gradient of the contaminated area and allowed to flow through the impacted area. The cosolvent with the mobilized contaminants is then extracted. A reverse gradient approach may also be used, which involves injecting at the down-gradient edge of impacts and then pumping the cosolvent solution from up-gradient wells.

Mobilizing contaminants for efficient mobilization and extraction. Surfactant flushing involves injecting a surfactant mixture into an aquifer impacted with Non-Aqueous Phase Liquids (NAPLs) to mobilize them. The surfactant and the mobilized NAPL are then removed through extraction wells, and either treated on-site or disposed of off-site. The surfactant mixture is typically injected up-gradient of the contaminated area and allowed to flow through the impacted area. The surfactant with the mobilized contaminants is then extracted. A reverse gradient approach may also be used, which involves injecting at the down-gradient edge of impacts and then pumping the surfactant solution from up-gradient wells.

Combining approaches for innovative solutions to complex impacts. By understanding the chemistry and biological processes occurring, IRSL can custom-develop hybrid treatment systems for individual sites. Examples of this includes the use of chemical oxidants with oxygen-releasing materials to promote both activated oxidation (high pH activates the oxidants) and bioremediation using the oxygen released by the hydrolysis of the oxygen releasing material. Similar reactions can be encouraged when using chemical reductants such as zero-valent iron and organic carbon materials. The compounds delivered can be physically placed or injected into the impacted aquifer using a variety of methods.

Cost-effective pump-and-treat systems. Goundwater “pump and treat” systems use pumps to extract contaminated groundwater from open excavations or one or more extraction wells. The liquid is then treated to separate or remove the contaminant from the groundwater. The remediated groundwater is discharged and the contaminant either mitigated or collected for disposal off-site.

Successfully removing NAPL from the subsurface. IRSL staff have designed, installed, maintained and optimized numerous Non Aqueous Phase Liquid (NAPL) removal systems, including multi-phase extraction, skimmers (pneumatic and belt), dual phase and vacuum-based systems. For our Province of Ontario clients, we hold numerous Certificates of Approval for LNAPL and DNAPL removal systems, which empower us to get on-site within two-to-three weeks.

Effectively removing volatile compounds from the vadose zone. Also called “in situ soil venting” or “vacuum extraction”, Soil Vapour Extraction systems reduce concentrations of volatile constituents absorbed into the subsurface by converting them from the solid (sorbed) and liquid (aqueous or non-aqueous) phases into the gaseous phase, and then removing them through extraction wells. Vapours are then treated above-ground. The system relies on vapour flow through the subsurface and extraction via wells specifically installed for vapour extraction. Vacuum extraction promotes vapour flow across a site, thus increasing the mass transfer driving force from aqueous (soil moisture), non-aqueous (pure phase), and solid (soil) phase into the gas phase. SVE is most effective for contaminants with higher Henry’s Law constants, such as benzene, toluene, ethylbenzene and xylenes, TCE and PCE.