In an anaerobic environment, some bacteria utilize chlorinated compounds as alternate electron acceptors for respiration through the process of reductive dechlorination. Through their respiratory process, bacteria sequentially replace chlorines with hydrogen. The biochemical reactions for complete dehalogenation of TCE through ethene are well documented.
Reductive dechlorination reactions for TCE occurs on a 1:1 molar basis (ie. one mole of TCE will be converted to one mole of cis-DCE and so on).
BRT has demonstrated enhanced anaerobic bioremediation of chlorinated solvents in situ. A brief description of a recent successful field deployment of BRT technology at a site with soil and groundwater impacted with chlorinated solvents in Western Pennsylvania follows. Historic site data showed consistent levels of trichloroethylene (TCE) occurring in groundwater. Pump and treat systems were installed over a 10 year span in attempts to remediate the contaminant. This approach proved extremely ineffective as TCE concentration showed very little movement over the same span. To enhance the reductive dechlorination process that was determined to be suitable by BRT analysis, site specific amendments needed to be introduced to the contaminated media. Addition of the hydrogen donating substrate, along with site specific nutrients, provided the hydrogen necessary for dechlorination of the solvents, thereby enhancing the remediation process on site.
The site has shown a clear decrease in TCE concentrations, with concomitant increases in both DCE and VC concentrations, significantly higher than any historical concentrations, followed by decrease in both DCE and VC to drinking water standards. After nine months of remediation, BRT showed degradation of all chlorinated compounds, including daughter products to below detection limits.
Most industrial processes use water, and with its use come the responsibility of achieving compliance with regulatory standards before it is discharged, or treating it so that it can be reused. Water is also discharged from industrial facilities as runoff from precipitation, which is commonly referred to as stormwater. In all cases, water that contacts an industrial process or the ground surface at a facility must obtain a permit to be discharged, such as USEPA’s National Pollutant Discharge Elimination System (NPDES) permit. NPDES permits require periodic reporting, often monthly, to a state or Federal regulatory agency that includes analytical test results of contaminants of concern, maximum limits of which are determined before a NPDES permit is issued.
BRT can assist you in many ways to comply your water discharge limits, from establishing and enhancing biological treatment units; to designing treatment systems; to performing sampling, testing and NPDES report preparation. BRT can also culture microbes that are native to your biological system and enhance their population to improve the end result. Or, during times of shutdown or maintenance activities, BRT can obtain water from your treatment units and grow and concentrate the native microbial population so that once the system is back on-line it can function normally in a fraction of the time.
BRT’s capabilities also include soil and groundwater assessment and remediation, utilizing biological processes alone or in conjunction with other common mechanical processes as may be appropriate to bring a project to the fastest conclusion possible. BRT’s biological processes are effective on degrading volatile organic compounds (petroleum and fuel products); chlorinated solvents (such as Perchloroethylene, Trichloroethylene and Vinyl Chloride); heavier hydrocarbarbon compounds; metals; and more.
BRT is available to act as your primary consultant on any problem you may have, or in a supplemental role to assist your staff personnel. We can also assist you with developing emergency management plans.
Volatile Organic Compounds is a collective name for many of the highest volume chemicals used in the US that have the capability of readily changing from a liquid or solid form into a gas. This transformation often occurs under normal temperature and pressure conditions found in outdoor and indoor areas. Volatility increases as temperature increases and pressure decreases. Many of the chemicals that make up gasoline and solvents are VOCs. Volatile organic compounds can produce adverse health effects through inhalation or direct contact. Also, they can be heavier than air and can accumulate in restricted areas posing a fire or explosion hazard.
VOCs in the environment are very treatable by biological methods. Petroleum compounds commonly found in fuels and oils are typically biodegraded by aerobic means, in the presence of oxygen, by microbes that live by breathing oxygen. Chlorinated organic compounds, such as the solvents Perchloroethylene and Trichloroethylene, often require anaerobic conditions for biodegradation, where there is a lack of oxygen. BRT is leading the way with newly developing technologies utilizing anaerobic reductive dechlorination, as a means of successfully biodegrading chlorinated organic solvents. This method is performed in-situ and requires very little space or infrastructure cost.
BRT can establish on-site, ex-situ treatment cells to biodegrade your contaminated soil and have it de-regulated and usable, eliminating disposal costs.
BRT can provide turn-key service for your project from start to finish, and is capable of assessing the extent of your problem as well as designing the appropriate remedial approach, whether it be biological, mechanical or a combination of both.
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