Chlorinated Solvents Contaminated Groundwater
Overview
Chlorinated aliphatic hydrocarbons such as chlorinated methanes, ethanes and ethenes are common groundwater contaminants that pose significant environmental and health risks. These solvents, such as perchloroethene (PCE: drycleaners), trichloroethene (TCE: metal fabricators and paint shops), chloroform (CF: chemical manufacturing) and 1,2-dichloroethane (DCA: mechanical workshops) can all be rendered harmless using bacteria we have in our library.
Our bioremediation solutions for chlorinated aliphatic hydrocarbons focus on enhanced reductive dechlorination, exploiting the catalytic abilities of organohalide respiring bacteria. These bacteria use chlorinated solvents for respiration in the same way we breathe oxygen. In doing so, they liberate chlorine atoms from the solvents, negating harmful impacts on human and environmental health. These unique bacteria are ancient inhabitants of Earth, pre-dating the appearance of oxygen in our atmosphere. They are ideal for cleaning up deep aquifer contamination where dense solvents migrate to oxygen free environments.
Microdiagnostic Evaluation
Whilst many labs in Australia can provide the chemical analysis, we are unique in our comprehensive suite of micro-diagnostic analysis tool. Our micro-diagnostics for chlorinated solvent contaminated sites include:
NextGen Bacteria Community Profile: for insights into the health, potential treatment inhibition, competitors to and helpful supporters of dechlorinating bacteria.
qPCR bacteria abundance of key reductive dechlorination species: Dehalococcoides (DHC), Dehalobacter (DHB), Desulfitobacterium(DSB) and Dehalogenimonas (DHG)
qPCR abundance of critical dechlorination functional genes: tceA (trichloroethene reductase) bvcA and vcrA(two critical vinyl chloride reductases),
qPCR abundance of electron donor competitors: Sulfate Reducing Bacteria (SRB) & methanogens (mcrA).
Treatability benchtesting
After the initial micro-diagnostic analysis, some sites may move directly to treatment. However, microcosm bench studies may be required to optimise treatment protocols. Bench-tests are particularly important if significant changes to groundwater conditions are required for reductive dechlorination, eg. pH or redox potential changes.
Microcosm studies can also be useful for the study of complementary abiotic amendments and provide site-specific support for your Remediation Action Plan.
Treatment
We supply a comprehensive range of products for successful bioremediation of PCE, TCE and other chlorinated ethene contaminated sites, including:
Bioaugmentation organohalide respiring culture mixes - Micronovo’s AusPCE, AusCF and AusDCA;
Electron donor systems - Emulsified Vegetable Oil or EVO;
Nutrient mix – providing nitrogen, phosphorus and trace elements needed for organohalide respiring bacteria;
Abiotic chemical treatments that complement bioremediation, such as Zero Valent Iron (ZVI).
Monitoring
Contaminant analysis only tells you part of the story, our analysis provides insights into why contaminant levels are changing (or not) and if treatment is working well or needs adjustment.
For example, stable contaminant levels may be due to source dissolution or desorption at similar rates to bioremediation. However, Compound Specific Isotope Analysis coupled with micro-diagnostics provides proof of bioremediation and can be used to estimate degradation rates.
Key monitoring packs for TCE/PCE contaminated sites are:
CSIA-PCE: C12/13 isotope analysis of PCE, TCE, cDCE and VC for monitoring of chlorinated ethene contaminated sites.
qPCR-PCE10: qPCR 10 key target pack for chlorinated ethene bioremediation monitoring, including key electron donor competitors. Total-Bact, DHC, DHB, DSB, DHG, tceA, bvcA and vcrA, , , SRB & mcrA.
Bespoke monitoring packs are available for CF and DCA contaminated sites, including targets that directly monitor our bioaumentation culture mixes.