Eastern PA Manufacturing Facility

The site has historically had soil and groundwater impacted by the use of the degreasing agents, tetrachloroethene (PCE) and trichloroethene (TCE). The in-situ pilot injection program targeted these compounds and their anaerobic daughter products.

A total of 19 injections were made in May and June 2009 over 2 days using an infiltration gallery, direct push points, and a deep injection well targeting specific zones with a straddle packer. The injections were made at 55-70 feet bgs in the deep bedrock zone, at 3-7 feet bgs using the infiltration gallery, and at 8-12 feet bgs in the direct push area.

The injection program utilized direct-push technology to apply blue green algae and kelp, essential nutrients (o-PO₄⁺ and NH₄⁺), sodium sulfite, calcium propionate, yeast extract, zero-valent iron (ZVI), EHC, and hydrogen release compounds (HRC-X and HRC).

The objectives of the program were to establish and maintain a stable dissolved hydrogen level, provide micro-nutrients, maintain pH, provide for optimal competitive conditions for the desired microbial consortia while minimizing the impact to the day-to-day operations of the facility (U.S. Patent 7,129,388).

Blue green algae and kelps were added in conjunction with organic hydrogen donors to provide necessary volatile fatty acids, as well as essential vitamins and nutrients for biological activity.

This Eastern Pennsylvania project demonstrates IET's patented (US 7,129,388) multi-amendment enhanced reductive dechlorination (ERD) approach — combining blue green algae, kelp, calcium propionate, yeast extract, sodium sulfite, ZVI, EHC, and hydrogen release compounds (HRC-X and HRC) in a single injection program. The staggered fermentation profile of these multiple organic substrates provides sustained hydrogen release from 0 to 1,500+ days, creating the continuous low-level hydrogen flux that selectively stimulates dechlorinating bacteria.

The multi-depth injection strategy — using deep wells, direct push, and infiltration gallery — demonstrates IET's capability to treat complex sites where contamination spans multiple geological units. The 99.99% TCE reduction in the direct push area (from 24 mg/L to 4.6 µg/L) demonstrates the effectiveness of this multi-amendment approach, with the biological treatment phase sustaining dechlorination long after the initial injection event.

The facility remaining operational during treatment is a key advantage of in-situ ERD over excavation-based approaches at active industrial sites. The multi-depth treatment approach — targeting bedrock fractures, overburden, and shallow zones simultaneously — ensures comprehensive treatment coverage across the site's heterogeneous subsurface, with each delivery method optimized for its target geological unit.

Eastern Pennsylvania encompasses several physiographic provinces including the Piedmont, Reading Prong, and Triassic Newark Basin. The multi-depth treatment approach used at this site — deep wells, direct push, and infiltration gallery — suggests contamination spanning both overburden and bedrock, typical of Piedmont or Triassic Basin settings where chlorinated solvents have migrated through saprolite into underlying fractured bedrock.

The three treatment methods tested successfully — deep well, direct push, and infiltration gallery — represent IET's comprehensive delivery capability for complex sites. Deep well injection targets bedrock fracture contamination using packer-isolated intervals. Direct push treats the saprolite overburden where contaminant mass is concentrated at the soil-bedrock interface. The infiltration gallery provides broad shallow treatment for residual contamination in the uppermost soil zone. The 42% downgradient CVOC reduction and 70%+ CVOC reduction in infiltration gallery wells demonstrate the effectiveness of this multi-depth approach.