Innovative Evapotranspirative Monocover and Groundwater Remediation at the OII Landfill Superfund Site
The 190-acre Operating Industries, Inc. (OII) Superfund Site is an inactive landfill site, about 10 miles east of Los Angeles, that for 30 years until 1984 received solid waste, and for a limited period, also accepted hazardous liquids. Parts of the landfill have steep slopes and waste up to 320 feet deep. The Site was placed on the National Priorities, or Superfund, List in 1986, and the U.S. EPA has referred to OII as "one of the most contaminated sites in the country." The entire Site is in an area of high seismic exposure and is immediately adjacent to residential neighborhoods, a commercial shopping complex, and the heavily-used Pomona Freeway. More than 20,000 people live within three miles of the Site. The U.S. EPA, under multiple Consent Decrees, required the PRP Group to implement a prescriptive full RCRA cap for the landfill and a traditional pump and treat system for hydraulic control and remediation of the groundwater. The cost estimate for this remedial method was $330 million. The PRPs then began looking for a more cost-effective alternative to the capping and groundwater treatment system. Any alternative method had to not only be more cost-effective, but it also had to be fully protective of human health and the environment.
