Bioremediation of Chlorinated Solvents in Groundwater
APTIM successfully designed and executed a treatability study of enhanced reductive dechlorination to bioremediate chlorinated solvents at a Superfund site.
Our team of technical experts delivered in-situ injection engineering services to perform groundwater bioremediation for a confidential government client, including:
- Designing in-situ injection of APTIM’s class-leading biotechnology, SDC‑9™, aligned with natural geochemistry to minimize effort and input quantities
- Enhancing subsurface delivery and site groundwater influence
- Observing groundwater chemistry changes of two to three orders of magnitude in the source area monitoring well, which originally contained solubility-level concentrations of perchloroethylene (PCE)
Project History
The bioremediation site was a former dry cleaner located in a small town. A deep public supply water well was located upgradient to the site’s natural groundwater flow, and a major interstate river is located within one mile of the site. The public supply system became impacted with perchloroethylene, and a search for the source of the groundwater impact resulted in the establishment of the subject site. No detections of chlorinated solvents have been observed to date in the river. A previous consultant led assessment and remediation of the site through 2021, at which point APTIM was selected to provide engineering services.
APTIM’s biotechnology laboratory also supplied SDC-9™, the world-renown biological inoculum containing bacteria of the genus Dehalococcoides. SDC-9 is proven to quickly and completely dechlorinate perchloroethylene into ethene gas, which is then readily off-gassed from the aquifer and degraded by typical microorganisms.
Previous remediation work at the site included in-situ chemical oxidation in 2016 and 2017, with minimal influence on native groundwater outside the injection wells. APTIM’s treatability study heavily influenced multiple monitoring wells within the test area, immediately demonstrating positive contact with and geochemical change in the impacted groundwater, including significant water table mounding and changes in chemistry by up to three orders of magnitude.
Our team provided engineering and technical execution staff and owned injection equipment to deliver services on time and in budget, while maintaining excellent relationships with affected property owners and tenants.
Services Provided
- Historical file and site assessment review
- Sampling for contaminant, natural attenuation, biological, and geochemical parameters
- Treatability test design, including reagents, biological inoculant, and injection well construction, to combat difficulties in prior testing
- Injection well installation, including three general vertical profiles and two drilling technologies to test efficacy of each well
- Real-time data collection and response, including adjustments to parameters such as location, pressure, flow, and mixtures to suit geological conditions
Learn more about APTIM’s site assessment, remediation, and closure services.
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