California Sea Grant College Program

The main goal of the project was to investigate the feasibility of treating ships' ballast water in existing municipal wastewater treatment plants (= publicly-owned treatment works or POTWs). The main objectives included identifying and characterizing the limiting factors that could restrict the volume of ballast water that can be treated at POTWs; and test, in a series of laboratory experiments, the effectiveness of standard municipal wastewater treatment in removing or killing ballast water organisms. We worked with staff of the City and County of San Francisco to analyse the effects of treating ballast water at San Francisco's Southeast Treatment Plant (SETP) as a model. We report here on the experimental tests and analyses of the effectiveness of treating ballast water organisms in POTWs.