Motiva Industrial Waste Landfill
The Motiva Industrial Waste Landfill was used by the Delaware City Refinery for disposal of refinery wastes. Petroleum coke (a byproduct of oil refinery coker units and cracker processes) and fly ash (fine particles that rise with flue gases), as well as chunk coke, inert debris, slag, oily dirt and bio filter cake from the Delaware City Refinery’s wastewater treatment plant from 1994 to 2004, when ownership of the Refinery was transferred from Motiva to Premcor.
EPA Exemptions to Hazardous Waste Laws
Fossil fuel combustion wastes, including fly ash, slag, are categorized by the EPA as “special waste” and are exempted from the federal hazardous waste regulations of the Resource Recovery and Conservation Act
Landfill is Lined
The landfill was initially lined with a double-liner system and a leachate collection system to prevent liquids in the landfill from contaminating groundwater.
A Closure for the landfill has been approved by the State of Delaware to cap the site and monitor pollutants. A cover has been installed on 18 acres of the landfill that includes 6 inches of topsoil, 18 inches of coarse-grained sandy fill, and a synthetic drainage net, a 60-mil geo-membrane, and bedding to encourage runoff to flow off the property and to infiltrate on adjacent land.
This closure plan is to prevent contaminants from the landfill from infiltrating into sources of drinking water and nearby streams and rivers, including Dragon Run, Red Lion Creek and the Delaware River. It is also intended to prevent direct soil exposure and contamination of vegetation.
Land Fill Gas Monitoring
In order to evaluate and address the potential for generation of degradation gases from these wastes, an initial landfill gas evaluation was performed on the different cells of the site. Wells were installed to a depth of 15 feet for the purpose of assessing potential gas that may be encountered.
Air was evacuated from each well via a peristaltic pump. The purged air was passed through monitoring equipment to measure concentrations of oxygen, methane, carbon dioxide and barometric pressure, Volatile Organic Compounds (VOCs), carbon monoxide, and hydrogen sulfide.