An oxygen scavenger is a remediation product used to remove dissolved oxygen from groundwater so that anaerobic biological processes can begin or continue. In many in situ bioremediation projects, naturally occurring oxygen prevents the microorganisms responsible for degrading chlorinated solvents from becoming fully active. By reducing dissolved oxygen, an oxygen scavenger helps establish the reducing conditions needed for enhanced anaerobic bioremediation.
An oxygen scavenger is not a replacement for an electron donor. Instead, it prepares the subsurface environment so microorganisms can effectively use the food provided by an electron donor. This makes oxygen scavengers an important part of many remediation strategies where anaerobic conditions are required for successful treatment.
Why An Oxygen Scavenger Is Important
Many chlorinated solvent sites contain the microorganisms needed to degrade contaminants, but those microorganisms cannot perform efficiently if dissolved oxygen remains too high. Even after an electron donor has been injected, oxygen may continue to interfere with the biological processes needed for reductive dechlorination.
An oxygen scavenger helps remove this obstacle by rapidly reducing dissolved oxygen levels and allowing the subsurface environment to transition toward anaerobic conditions. Once these conditions are established, microorganisms can more effectively use the food provided by the electron donor to support biological treatment.
Creating the proper subsurface environment is often just as important as selecting the right remediation products. Successful in situ bioremediation depends on matching the treatment approach to site conditions and ensuring that all of the necessary biological processes can occur.
How an Oxygen Scavenger Works
An oxygen scavenger reacts with dissolved oxygen in groundwater, reducing oxygen concentrations and helping lower oxidation-reduction potential (ORP). As oxygen is removed, groundwater conditions become more favorable for anaerobic microorganisms involved in processes such as reductive dechlorination.
Once anaerobic conditions have been established, electron donors provide food for microorganisms, allowing them to grow and remain active. As the microorganisms consume the electron donor, they produce the compounds needed to support continued biological activity and contaminant degradation.
The effectiveness of an oxygen scavenger depends on many site-specific factors, including dissolved oxygen concentrations, groundwater chemistry, groundwater flow, injection methods, and the distribution of amendments throughout the treatment zone. Proper distribution is essential because anaerobic conditions must be established wherever biological treatment is expected to occur.
Common Applications for Oxygen Scavengers
Oxygen scavengers are commonly used during in situ remediation projects involving chlorinated solvents such as PCE, TCE, DCE, vinyl chloride, and other contaminants that require anaerobic biological treatment.
They are often applied before or together with electron donors to accelerate the establishment of reducing conditions. Oxygen scavengers may also be used in combination with bioaugmentation cultures when specialized microorganisms are introduced to a site. By reducing dissolved oxygen, they help create an environment where these microorganisms can survive, establish themselves, and effectively degrade contaminants.
Site conditions always determine whether an oxygen scavenger is appropriate. Groundwater chemistry, contaminant type, dissolved oxygen levels, soil characteristics, and treatment objectives should all be evaluated before selecting a remediation strategy.
RNAS Technical Insight
One of the most common misconceptions in anaerobic bioremediation is that adding an electron donor alone will immediately create the conditions needed for successful treatment. In reality, dissolved oxygen can delay the development of anaerobic conditions, reducing the effectiveness of the remediation program.
An oxygen scavenger helps remove this obstacle, but successful remediation still depends on understanding site conditions and distributing amendments throughout the treatment zone. Even the best remediation products cannot perform effectively if they do not reach the contaminated areas where biological treatment is needed.
Related RNAS Products
Newman Zone OS is an oxygen scavenger specifically designed to rapidly remove dissolved oxygen and help establish anaerobic conditions. It is often used alongside Newman Zone 55, Newman Zone HRO, Newman Zone QR75, or Newman Zone QR90 to support enhanced anaerobic bioremediation. When bioaugmentation is part of the treatment strategy, Newman Zone OS also helps create favorable conditions for SDC-9 and other anaerobic microbial cultures to become established and actively degrade chlorinated solvents.
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