Dechlorination of cVOC

Dechlorinating bacteria are highly specialised bacteria that derive energy for growth by removing chlorine molecules from organic compounds (such as ethenes, benzenes, phenols, etc.) under anaerobic conditions. This also called “reductive dechlorination” or “dehalorespiration”.

These specialised bacteria are increasingly being used for remediation of sites that are contaminated with chlorinated compounds such as tetrachloroethene (PCE), trichloroethene (TCE), trichloromethane (chloroform) and many others. These chemicals are frequently used as solvents and degreasers by industries such as dry-cleaners, metal industries, etc. and have become significant groundwater contaminants that are toxic to humans (see for example the US Substance Priority List http://www.atsdr.cdc.gov/SPL/index.html).

The best known example are the Dehalococcoides bacteria which were discovered in 1997 and are now put to work all over the world to remediate groundwater that is contaminated with the solvents PCE and TCE. Dehalococcoides can degrade these solvents to the harmless end products ethene and ethane. This is unique to Dehalococcoides bacteria. In the meantime hundreds of remediation projects using these bacteria have been performed throughout the world and many publications are available on how they do it.

To get the bacteria to degrade chlorinated ethenes it is essential that the right conditions are present in the ground (for example no oxygen, nitrate or sulphate, sufficient nutrients, the right pH, etc.). Of course the right bacteria need to be there too.

To determine whether Dehalococcoides bacteria are present and to monitor if their numbers are increasing as a result of their eating the contaminants, Orvion has developed the ORVIdetect DBA-ethene analysis. Using this analyses the multiple species of Dehalococcoides are determined, including:

* Dehalococcoides sp. BAV1 (has specific activity for degradation of vinyl chloride)
* Dehalococcoides sp. VS (has specific activity for degradation of vinyl chloride)
* Dehalococcoides mccartyi GT
* Dehalococcoides mccartyi strain 195 (previously Dehalococcoides ethenogenes sp. 195)
* Dehalococcoides mccartyi DCMB5
* Dehalococcoides mccartyi BTF08
* Dehalococcoides mccartyi GY50
* Dehalococcoides sp. MB

If no (or not enough) Dehalococcoides bacteria are present at a site then it’s possible to augment a location with a concentrate containing high numbers of bacteria to get remediation started. Orvion has a concentrate available that contains approximately 10 million (107) Dehalococcoides bacteria per millilitre. By augmenting your site with this concentrate you can kick-start biodegradation and get more assurance that you will achieve your remediation results.

Put the Dehalococcoides bacteria to work at your location too!

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