ERMA FIRST Ballast Water Treatment System Modern vessels cannot just pump ballast water in and out anymore. Under the IMO Ballast Water Management (BWM) Convention, ships must treat ballast water so they don’t spread invasive marine organisms from one region to another. This post gives a simple overview for deck officers, engineers and ratings. Detailed operation and maintenance are covered in the manuals attached below. 1. What Is ERMA FIRST BWTS? ERMA FIRST is a Greek manuf