Remediation and Restoration (Pilot Treatability Testing): Maywood, CA

CERCLA RI/FS and RD/RA, Pemaco Superfund Site, CA
CERCLA RI/FS and RD/RA, Pemaco Superfund Site, CAOTIE completed a CERCLA remedial investigation and feasibility study (RI/FS) and remedial design and remedial action (RD/RA) at the Pemaco Superfund Site in Maywood, CA. OTIE was tasked with four TOs for the entire CERCLA process—RI/FS, risk assessment, EE/CA, treatability study/pilot test, community involvement, RD, RA, system start-up, system optimization, LTO/LTM, data management, and reporting.
The Pemaco site is a 1.4-acre former chemical facility in a mixed-use area adjacent to the Los Angeles River. Physical conditions are complex—releases from USTs, ASTs, and drums caused soil contamination over 90 feet deep and groundwater contamination in a complex composite leaky-confined aquifer system with multiple VOCs (primarily TCE up to 28,000 ug/L) down to 170 feet across 14 acres migrating under residential properties and threatening local water wells. The site was redeveloped by the City as a public park with OTIE providing RD and RA construction services. OTIE performed the following:

    • Used the USEPA Triad Approach to develop a dynamic Work Plan to streamline investigations and collect over 3,000 multi-media samples
    • Sampled soil vapor from 125 locations and 81 residential air samples to assess VOC vapor migration and the vapor intrusion pathway.
    • Installed 79 monitoring wells (to a maximum depth of 175 feet) across 5 groundwater zones; installed over 75 on- and off-site soil borings. Analyzed 175 surface soil samples and 250 subsurface soil samples.
    • Developed an EDMS database with 1,500,000 data records linked to ArcInfo GIS and to web-based Environmental Enterprise Solutions (EES™) for data access by all stakeholders.
    • Performed a complex human health risk assessment to identify baseline risks and develop PRGs for 57 COCs, e.g., TCE and PCE.
    • Developed a complex FS that divided the site into 5 depth-specific treatment zones screening over 80 remedial technologies for each zone; performed detailed evaluations for 13 technologies per zone.
    • Provided community involvement assistance by developing several bilingual (English/Spanish) Fact Sheets and Proposed Plan, mailed to over 7,000 households, and supporting public meetings.
    • Constructed multi-zoned, 68 well, high-vacuum dual-phase extraction system and electrical resistance heating (ERH) system with SVE and innovative ceramic core flameless thermal oxidation with acid gas scrubbing and GAC to control potential dioxin emissions.
    • Performed remediation system start-up and O&M.
    • Presently performing Long-Term Response Action.


Client Name: USACE Omaha District

Location: Maywood, CA

Contract Value: $15M

Project Features:

  • Innovative solutions to complex chlorinated solvent contaminated site conditions
  • Tested, designed, and implemented innovative ERH with SVE
  • Optimized operation with real-time web-based controls