EPA AIMS TO CUT OFFSHORE PLATFORM DISCHARGES

The Environmental Protection Agency has proposed rules to sharply reduce U.S. offshore platforms' discharges into the ocean. The rules will require more treatment of waste discharges from new and existing platforms. EPA estimates the changes will cost industry about $80 million/year and prevent release of about 14 million lb/year of pollutants into the ocean, including about 1.4 million lb/year of toxic substances.

March 18, 1991

4 min read

The Environmental Protection Agency has proposed rules to sharply reduce U.S. offshore platforms' discharges into the ocean.

The rules will require more treatment of waste discharges from new and existing platforms.

EPA estimates the changes will cost industry about $80 million/year and prevent release of about 14 million lb/year of pollutants into the ocean, including about 1.4 million lb/year of toxic substances.

The rules will limit the discharge of oil and grease, toxics, drilling fluids and cuttings, produced water, and miscellaneous wastes such as deck drainage, produced sand, chemical well treatment fluids, and domestic and sanitary wastes.

The agency will receive comments on the rules at 9 a.m. to 2 p.m. workshops Apr. 9 at the Radisson Suites Hotel in New Orleans and Apr. 11 at the Sheraton Santa Barbara Inn in Santa Barbara, Calif.

When EPA issues the final rules in June 1992 they will be incorporated in new National Pollutant Discharge Elimination System (Npdes) permits that will be issued to all new platforms and to all existing platforms by 1995.

EPA said the rules affect about 2,260 oil and gas producing platforms containing 13,000 wells off the U.S. It said 2,233 are in the Gulf of Mexico, and the rest are off California. It said the rules especially will protect shallow water environments, within 4 miles of shore, where many platforms are sited.

WHAT THEY DO

The proposed rules supplement regulations EPA issued Aug. 26, 1985, for the offshore oil industry. Some items proposed in 1985 remain unchanged.

Proposed effluent limitation guidelines require use of best available technology economically achievable (BAT) and best conventional pollutant control technology (BCT). BAT and new source performance standards (NSPS) effluent limits are proposed for produced water equal to the best practical control technology currently available (BPT) for platforms more than 4 miles from shore.

For structures less than 4 miles from shore, EPA proposes produced water effluent limits for oil and grease based on membrane filtration as an add on technology to BPT. The limits are 17 mg/I./month and 13 mg/l./day.

For drilling fluids and drill cuttings, wells more than 4 miles from shore are subject to effluent limits for toxicity of 30,000 ppm, cadmium and mercury limits of 1 mg/kg each in drilling fluids and drill cuttings discharges, and a requirement for no discharge of diesel oil and free oil.

For wells 4 miles or less from shore, zero discharge of drilling fluids and drill cuttings is proposed. An exception to the drilling fluids and cuttings limits is proposed for Alaska.

BAT and NSPS are also being proposed for miscellaneous waste streams: deck drainage, produced sand, treatment, completion, and workover fluids, and domestic and sanitary wastes.

Zero discharge is proposed for the produced sand (solids) waste stream, and for treatment, completion, and workover fluids when they resurface as a discrete slug. Otherwise, if these fluids do not surface as a discrete unit, they would be commingled with and treated along with produced water.

EPA proposes that deck drainage be subject to the same limits as produced water during the production phase of offshore operations. During the exploration phase, deck drainage will be subject to BPT limits barring discharge of free oil.

EPA does not propose BAT for domestic and sanitary wastes because they contain no toxic or nonconventional pollutants. NSPS for sanitary wastes would be the equal to BPT, and domestic wastes would be equal to the current permit requirements prohibiting discharge of floating solids.

BCT for produced water is proposed equal to BPT. BCT for drilling fluids and drill cuttings is proposed equal to the zero discharge for structures 4 miles or less from shore and BPT for structures more than 4 miles from shore.

The proposed BCT requirement is no discharge of free oil in effluents such as well treatment, completion, and workover fluids, and for deck drainage and produced sand. BCT sanitary wastes limits would control residual chlorine at platforms with 10 or more personnel and no discharge of floating solids.