Oily Sludge Biodetoxification

The Scranton Army Ammunition Plant (SCAAP) in Scranton, PA, is one of the few industrial facilities capable of forging large caliber projectiles used by the military. To keep the hot (2300 F) freshly forged projectiles from sticking to the forge, a mineral oil based lubricant that has graphite suspended in it is used to lubricate the forge. The spent forging oil along with cooling water collects in trenches under the forges and is sent to an oil water separator (OWS), and the recovered sludge is landfilled. However, the OWS functioned poorly and the concentration of oil in the discharge water often exceeded the permitted limit. During the course of the project, SCAAP installed a skimmer that captures much of the oil, which is recycled. However, even after skimming, the concentration of oil in the water exceeds the discharge limit permitted by the Scranton Sewer Authority. In addition to Scranton, treatment plants, wash racks, fuel depots, industrial operations, and maintenance facilities at U.S. Department of Defense (DoD) activities annually generate millions of gallons of wastewater contaminated with thousands of tons of oily sludge. Collecting and disposing non-recyclable oily sludge is increasingly costly and time consuming. In the Navy, the yearly operation and maintenance (O&M) costs associated with OWSs and bilge oily wastewater treatment system (BOWTS) units are estimated to be $24 million, and the Army estimates that the cost for disposing of oily sludge generated at wash racks alone is $150,000 per base. In the civilian sector, the U.S. Environmental Protection Agency (USEPA) estimates that oily sludge disposal costs $2 billion per year. As an alternative to the current practice (landfill disposal), which is increasingly costly and restricted, on-site bioremediation offers attractive cost savings and eliminates long-term liability associated with landfill disposal.