Slurry Wall and Cover System for Redevelopment of the McColl Superfund Site

Geosyntec and our project team designed and implemented a final remedy at the McColl NPL Site that saved our clients over 93% of the original remedy costs. Geosyntec and our project team designed and implemented a final remedy at the McColl NPL Site that saved our clients over 93% of the original remedy costs.

The McColl Superfund site is a 20-acre former industrial waste disposal facility. From 1942 to 1946, petroleum sludges and other wastes from the production of high octane aviation fuel were placed in 12 unlined pits. In the 1950s, in an effort to control odors and gaseous emissions from the site, several of the pits were covered with diesel oil-based drilling mud. The site was placed on the National Priorities, or Superfund, List in 1982.

In 1984, under a CERCLA Unilateral Administrative Order (UAO), the U.S. EPA directed the Potentially Responsible Parties (PRPs) to implement a remedy consisting of excavation and off-site disposal of hazardous wastes that was estimated to cost in excess of $200 million. New residential development and a golf course surrounding the site complicated the remediation, and tarry seeps and malodorous emissions were emanating from the site.

Geosyntec's Scope of Services

The PRPs retained a project team that included Geosyntec as a technical consultant. The team successfully demonstrated the technical impracticality of the U.S. EPA-proposed excavation and off-site disposal remedy. In 1993, the U.S. EPA developed a revised remedy that involved on-site solidification and stabilization that was estimated to cost $85 million. Applying technical arguments developed by Geosyntec, the PRP Group then negotiated with the U.S. EPA to eliminate the solidification component from the remedy. As part of the negotiation process, our team proposed to work under an "over the shoulder review" process which, when implemented, allowed timely agency review.

Geosyntec and our team designed a RCRA-equivalent final cover system over, and a vertical subsurface barrier around, the pits. The cover system was capable of supporting part of the adjacent golf course, and construction of the barrier system was in recognition of the proximity of residences. We designed the remedial system to tie the final cover system into the subsurface barrier wall. Upon completion, the final cover system was developed as a park-like setting, which resulted in the restoration of three holes from the adjacent golf course which had been abandoned to allow remediation of the pits.

Notable Accomplishments

The ultimate remedy that Geosyntec and our project team designed and implemented at the McColl site, originally estimated to cost $15 million, was completed in 1997 at a cost of only $13 million. This represented an ultimate savings to our client of $187 million, or 93%, over the original $200 million excavation and off-site disposal remedy that had been proposed by the U.S. EPA.

The cooperation that was engendered between the project team, the PRPs, and the regulators set a new standard of practice for such a large and complex project. Our team was able to complete the design and construction process in only two years, allowing the first round of golf to be played in 1998.

Project Overview

  • Location: Fullerton, California, USA
  • Client: McColl Site Group
  • Project Practice Areas: Contaminated Site Assessment and Cleanup
  • Type of Facility: Closed Industrial Site
  • Services Provided: Conceptual Design; Final Design Plans and Specifications; Regulatory Negotiation; Construction Quality Assurance
  • Type of Work: Brownfield Redevelopment
  • Company: Geosyntec Consultants
  • Governing Regulation: Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
Geosyntec Consultants
Geosyntec is a specialized consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural resources, and civil infrastructure.

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