Integrated Refinery Waste Management

Abstract

In response to the RCRA land ban regulations and TC rule promulgated by the U.S. Federal Environmental Protection Agency (EPA) in 1988-1990, an Integrated Refinery Waste Management (IRWM) program has been developed to provide cost-effective solutions to petroleum industry customers. The goal of IRWM is to provide technology based remediation treatment services to manage sludges and wastewaters generated from the oil refining processes, soils contaminated with petroleum distillates and groundwater contaminated with fuels. Resource recovery, volume reduction and waste minimization are the primary choices to mitigate environmental problems. Oil recovery has been performed through phase separation (such as centrifugation and filtration) and heating of heavy oils. Volume reduction is achieved by dewatering systems such as centrifuges and filter presses, and low temperature thermal treatment. Waste minimization can be accomplished by bioremediation and resource recovery through a cement kiln. In-situ vapor extraction has been applied to remove volatile organic compounds from the vadose zone in contaminated sites. Stabilization has been effective for soils contaminated with heavy metals and nonvolatile substances. For the listed hazardous wastes generated from the refining process, a combination of liquid/solids separation and thermal treatment has been successfully applied. The sludge from the on-site ponds or continuous operations is pumped to a surge tank before heating, phase separation and volume reduction by a two-stage centrifuge system. The first stage horizontal centrifuge has effectively separated the solids from the liquid phase containing oil and water. The oil in the liquid phase is separated from the water in the second stage vertical centrifuge and is recycled back to the refinery for re-use. The water will be sent back to the wastewater treatment system for further treatment. Pretreatment of the wastewater may be required.