Home Remediation Remediation Techniques Biological Technologies Anaerobic Dehalogenation
Anaerobic Dehalogenation

A majority of chlorinated compounds can be dehalogenated using specific indigenous soil bacteria. Unlike aerobic bacteria dehalogenating bacteria utilise hydrogen as an electron donor to complete the metabolism of the chlorinated compounds.

A majority of chlorinated compounds can be dehalogenated using specific indigenous soil bacteria. Unlike aerobic bacteria dehalogenating bacteria are anaerobic, utilising hydrogen as an electron donor to complete the metabolism of the chlorinated compounds.

Organic containing compounds like lactic acid, whey, HRC™ and edible oils can be used as a source of hydrogen, which is released as a result of staged fermentation (another biological process). Key to the success of a biological dehalogenation process is the creation of an oxygen free reduced environment, which is aided by the fermentation process.

The application of organic substrates requires knowledge of sub-surface conditions as a number of reducing bacteria can compete for the available electron donors produced. A number of tests and/or assessments can be undertaken to determine the suitability of a chlorinated hydrocarbon impacted site for anaerobic dehalogenation. This includes the measurement of competing chemical species e.g. manganese, sulphate and iron and identification of specific dehalogenating bacteria. Another factor that needs consideration is the geology and hydrogeology, which may limit the distribution of injected donor products. This can be overcome by selecting donor products with favourable physical properties for the conditions encountered and use of suitably robust delivery techniques.

Like all in-situ biological methods careful consideration needs to be given to the presence of source zones, which will be resistant to biological processes and have the capacity to act as a long-term source. The time it takes to establish the right conditions for dehalogenation, the time to complete the process and the active lifespan of the selected organic substrate also needs to considered if a successful outcome is to be achieved. Churngold can provide assistance with all of the aspects of the design to ensure a successful outcome.