Injection of electron donors, electron acceptors, or nutrients into the subsurface to stimulate indigenous microorganisms to biodegrade target contaminants. Distinct from bioaugmentation, which adds external organisms.
Biostimulation modifies subsurface geochemistry to favour the metabolic pathway that degrades the target contaminant. For anaerobic reductive dechlorination of chlorinated solvents, an electron donor such as lactate, emulsified vegetable oil, sodium acetate, or molasses is injected to drive ORP strongly negative and supply carbon for dechlorinating bacteria. For aerobic petroleum-hydrocarbon biodegradation, oxygen (via sparging, oxygen-release compounds, or hydrogen peroxide) and inorganic nutrients are added.
Biostimulation is often the first line of biological treatment because it leverages the native microbial community without the regulatory and cost overhead of adding cultured organisms. When the indigenous community lacks the required species, biostimulation is followed by bioaugmentation.
Also known as: biostimulation.
The SO₄²⁻ oxyanion released to groundwater and surface water from acid mine drainage, oilsands process water, industrial effluent, and gypsum-bearing geology; regulated for taste and osmotic effects and for downstream sulfide generation in anaerobic sediments.
An ex-situ soil treatment process that heats contaminated soil to volatilize and separate organic contaminants from the soil matrix, after which the liberated vapors are captured and treated, usually in a high-temperature oxidizer.
A thermal desorption configuration where the heat source contacts the soil directly inside the rotary unit, delivering high heat-transfer efficiency and supporting higher treatment temperatures.
A thermal desorption configuration where heat is conducted through the wall of the treatment vessel without combustion gases contacting the soil, producing a concentrated, lower-volume vapor stream suitable for condensation and recovery.
Treatment that heats contaminated soil and groundwater in place, typically with electrical resistance, thermal conduction, or steam injection, to volatilize and recover contaminants without excavation. Used where excavation is impractical or where the contaminant zone sits beneath active infrastructure.