ORGANOTIN ANTIFOULING PAINTS AND THE ENVIRONMENT — DRYDOCK PHASE

Fuel savings of several hundred million dollars annually are expected from a pending Navy decision to use antifouling hull paints based on tributyltin compounds. Several Navy and commercial ship trials have demonstrated that these paints routinely outperform the current military specification paints based on cuprous oxide. Additional savings are expected as a result of less frequent drydocking and the elimination of underwater hull cleaning. However, because the organotin compounds are more toxic than cuprous oxide, the potential effect on the environment must be considered. Organotin discharge regulations and current drydock practices are reviewed, and the quantity of organotin generated during drydock operations is estimated. An environmental assessment of the Fleet-wide use of organotin antifouling paint is in preparation. Several procedures and processes to manage organotin paint wastes have been evaluated. They include landfill disposal of solid waste; incineration of solid waste; wastewater treatment plant disposal of organotin-contaminated water; activated carbon removal of organotin from wastewater; paint application and removal within an enclosure; paint removal with cavitating water jets; and paint removal with high energy beams. It is anticipated that a proper combination of these procedures and processes will provide adequate management of organotin wastes to protect the environment.