SiREM employees Sandra Dworatzek and Jennifer Webb co-authored article with Geosyntec Consultants entitled “Optimization and validation of enhanced biological reduction of 1,2,3-trichloropropane in groundwater” that was published in Remediation Journal on pages 17–25, Volume 28, Issue 1, Winter 2017.

Ms. Dworatzek is a Senior Manager of SiREM. and is an environmental microbiologist with advanced technical experience in laboratory treatability studies. Over the past 24 years she has conducted and overseen numerous bench-scale studies examining enhanced in situ remediation in groundwater. She has specific technical experience in the design of laboratory treatability studies, the scale up of growth of an anaerobic microbial culture for bioaugmentation laboratory and field pilot tests, and evaluation of aerobic and anaerobic bioremediation, zero valent iron and chemical oxidation technologies in the laboratory.

Ms. Webb is a Senior Laboratory Technician at SiREM. She conducts and oversees treatability studies for a wide range of environmental contaminants, including halogenated organics (e.g., solvents, pesticides, etc.), both alone and in complex mixtures. She currently oversees research and development for KB-1® and KB-1® Plus dehalorespiring microbial cultures that have been widely used in field demonstrations to improve the rate and extent of bioremediation of chlorinated solvents in groundwater (e.g., tetrachloroethene (PCE) and trichloroethene (TCE) dechlorination to ethene), as well as the development of new bioaugmentation cultures for 1,2,3-trichloropropane, chloroform, benzene, toluene and xylene.

The Remediation Journal is known as the journal of cleanup costs, technologies, and techniques and it has been honored by industry peers with an Award for Publication Excellence at the 2016 APEX Awards.


Laboratory and field demonstration studies were conducted to assess the efficacy of enhanced biological reduction of 1,2,3-trichloropropane (TCP) in groundwater. Laboratory studies evaluated the effects of pH and initial TCP concentrations on TCP reduction and the activity of a microbial inoculum containing Dehalogenimonas (Dhg). Laboratory results showed successful reduction at a pH of 5 to 9 with optimal reduction at 7 to 9 and at initial TCP concentrations ranging from 10 to over 10,000 micrograms per liter (μg/L). Based on findings from the laboratory study, the effects of TCP concentration, geochemical conditions, and amendment concentration on bioremediation efficacy were investigated during a field demonstration at a site with relatively low initial concentrations of TCP (< 2 μg/L). The field demonstration included injection of emulsified vegetable oil (EVO) and lactate as a carbon substrate for biostimulation, followed by bioaugmentation using the microbial inoculum containing Dhg. Post-injection performance monitoring demonstrated reduction of TCP to below laboratory detection limits (< 0.005 μg/L) after an initial lag period of approximately six months following injections. TCP reduction was accompanied by generation of the degradation byproduct propene. A marginal increase in TCP concentrations, potentially due to an influx of upgradient aerobic groundwater containing TCP, was observed eight months after injections thereby demonstrating the sensitivity of this bioaugmentation application to changes in geochemical parameters. Despite this marginal increase, performance monitoring results indicate continued TCP biodegradation 15 months after implementation of the injection program. This demonstration suggests that enhanced biodegradation of TCP by combining biostimulation and bioaugmentation may be a promising solution to the challenges associated with remediation of TCP, even when present at low part per billion concentrations in groundwater.

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