Bioremediation at a petroleum refinery

This paper presents a summary of three projects at the Mobil Refinery in Torrance, California where bioremediation technologies were successfully employed for the remediation of hydrocarbon contaminated soil. The three projects represent variations of implementation of bioremediation, both in-situ and ex-situ. Soil from all of the projects was considered non-hazardous designated waste under the California Code of Regulations, Title 23, section 2522. The projects were permitted and cleanup requirements were defined with the Los Angeles Regional Water Quality Control Board. In all of the projects, different methods were used for supplying water, oxygen, and nutrients to the hydrocarbon degrading bacteria to stimulate growth. The Stormwater Retention Basin Project utilized in-situ mechanical mixing of soils to supply solid nutrients and oxygen, and a self-propelled irrigation system to supply water. The Tank Farm Lake project used an in-situ active bioventing technology to introduce oxygen, moisture, and vapor phase nutrients. The Tank 1340X247 project was an ex-situ bioventing remediation project using a drip irrigation system to supply water and dissolved nutrients, and a vapor extraction system to provide oxygen