A large military installation in California generated 7.9 million pounds of oil/water separator (OWS) waste in 1998. Because the OWS waste contains oily components and was presumed to fail the aquatic toxicity test, the installation recategorized the OWS waste from nonhazardous to a California hazardous waste. This change in categorization resulted in a large increase in disposal costs and volumes for the facility. In 1999, the installation began contracting the onsite recycling of the waste using a mobile gravity separation unit in an effort to control disposal costs.
In 1999, CH2M HILL evaluated the onsite recycling process as part of the Senate Bill (SB)-14 report/plan and suggested that the recycled water had a beneficial reuse in California because of the arid climate. It was shown that 87 percent of the OWS waste could be regenerated as clean water with 0.8 percent sent offsite as oil for recycling. Only 1.5 percent was determined to be a hazardous waste residue from the recycling process. The other 11 percent was sediment that was dried and applied to the onsite landfill as a daily cover. All of these activities meet the HSC criteria and, as a result, the installation appears to qualify for the recycling exemption.
The overall results for the installation have been a drastic reduction in hazardous waste quantities and a beneficial reuse of water. For the next SB-14 reporting cycle, these waste minimization results could be truly impressive.