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Slurry phase biodegradation (also known as bioreactor remediation) is a relatively more rapid process compared to the other treatment processes. The process is a controlled treatment process that involves the excavation of the contaminated soil, mixing it with water, and placing it in a bioreactor.

In the process, contaminated soil is combined with water and other additives in a large tank (the bioreactor) and mixed to keep the microorganisms, which are already present in the soil, in contact with the contaminants in the soil. Nutrients and oxygen are added, and conditions in the bioreactor are controlled to create the optimum environment for the microorganisms to degrade the contaminants. When the treatment is complete, the water is removed from the solids, which are sent for disposal or treated further if they still contain pollutants.

Slurry reactors or aqueous reactors are used for ex situ treatment of contaminated soil and water pumped up from a contaminated plume. Biodegradation in reactors involves the processing of contaminated solid material such as soil, sediment, sludge, or water through an engineered containment system.

A slurry bioreactor is a containment vessel and apparatus used to create a three- phase system, such as solid, liquid, and gas, mixing condition to increase the biodegradation rate of soil-bound pollutants and water-soluble pollutants as a water slurry of the contaminated soil and biomass capable of degrading target contaminants.

In general, the rate and extent of biodegradation are greater in a bioreactor system than in situ or in solid-phase systems because the contained environment is more manageable and hence more controllable and predictable. However, the contaminated soil may require pretreatment or, alternatively, the contaminant can be stripped from the soil via soil washing or physical extraction before being placed in a bioreactor.

See also: Biodegradation, Biodegradation In Situ, Biodegradation Processes, Biodegradation – Solid Phase.