Evaluating the contingency treatment performance of advanced electro-catalysis oxidation processes for marine bacteria in ballast water

Abstract

Effects of ballast water treatment by advanced electro-catalysis oxidation processes (AEOP) on abundance, activity, and diversity of marine bacteria were examined in a full-scale ballast water management system (BWMS) at Yangshan Port, Shanghai, China. Water samples were collected immediately after treatment and at discharge to evaluate the contingency treatment performance of the BWMS for bacteria. After treatment, the total viable count reduced to 0.7 104 CFU·mL-1, and both Escherichia coli and enterococci decreased to 10 CFU·100 mL-1, which satisfied the D-2 Standard of the International Maritime Organization. AEOP can be as an effective contingency reception facility. Sequencing of 16S rRNA gene amplicons demonstrated the declining trend in bacterial diversity, and while the treatment did not completely eliminate the risk of bacterial dispersal, potentially pathogenic bacteria survived in treated and discharged samples. Bacterial diversity is of greater concern when evaluating effects of ballast water treatment on microorganisms because the bacteria which can develop adaptive mechanisms to environmental change will have a greater potential for invasion in the new environment.