January 12, 1997 -- VALDEZ, AK -- The search for the source of sheen on the water near the Valdez Marine Terminal has narrowed to the Ballast Water Treatment Facility. Although the evidence is not conclusive, several factors indicate that the sheen could have originated at the facility, which treats tanker ballast water and releases it near Berth 3. The area around the diffuser outfall has been surrounded by containment boom.

In the backup system of the ballast water treatment process, plastic balls are used to disperse the water and allow air to remove any remaining hydrocarbons. Remnants of these balls were collected during the sheen recovery operations. The BWT receives ballast water from the tankers and treats it through a manual and biological process for subsequent release. On Thursday evening, the biological treatment stage was operating at low levels and the backup system was engaged to treat the ballast. This situation occurs several times a year, typically following rough weather conditions, and is allowed under a federal and state permit.

The BWT plant was shut down at 2:00 p.m. today to clean the backup system. Operation of the BWT facility will resume in the morning. Tomorrow an overflight of the area will take place and if additional sheening is sighted the BWT operation will be shut down. Additional investigation of the BWT is being conducted to determine whether it is the source of the sheen. Alyeska is sampling the BWT discharge every hour. As part of normal operations, composite samples of BWT discharge are collected every day. An investigation team comprised of technical experts along with the Alaska Department of Environmental Conservation and the Environmental Protection Agency has been activated.

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