TranslateHorsham Manufacturing Facility
The site has historically had soil and groundwater impacted by the use of 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 including the use of an infiltration gallery, direct push points, and a deep injection well. 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.
Deep Well Results (November 2009):
- PCE: 72.5% decrease (6.4 to 1.9 µg/L)
- TCE: 92% decrease (17 to 1.3 µg/L in 0-65' zone)
- cis-1,2-DCE: 100% decrease (58 to non-detect µg/L)
- Vinyl Chloride: 100% decrease (4.1 to non-detect µg/L)
Direct Push Area Results:
- Total CVOC: 99% decrease
- TCE: 100% reduction (24 mg/L to non-detect)
- Only vinyl chloride remained measurable (100 µg/L, above PA standard)
Infiltration Gallery Results (MW-6S):
- 70% or greater CVOC reduction in most wells within one year
- Biologically-dominated reductive dechlorination achieved
