Client: Confidential (Oil Refiner)
Location: Pennsylvania Project
Duration: 7 months
Description: An oil refinery in west central Pennsylvania produced an acidic sludge from processing lubricating oil. The process used sulfuric acid and clay to remove impurities from raw materials; and the resulting sludge consisted of asphaltic sludge, clay, and sulfuric acid. For more than forty years this acidic sludge was deposited in excavations from an old strip mine. This project required us to remediate the site by neutralizing the sludge, then consolidating the neutralized sludge within a disposal cell and covering it with a synthetic liner. Approximately 100,000 cubic yards of sludge were neutralized and placed into a disposal cell. Because the sludge exhibited physical characteristics ranging from tar to slag, we used a shearing injector for injecting reagents into the sludge. Since the sludge varied from seven to 60 feet deep, it was treated in five- to 10-foot layers. Sulfur dioxide and hydrogen sulfide emissions are major concerns when treating acidic sludge. These emissions were mitigated by utilizing water, lime based reagents, and special mixing and injection techniques.