Vessel-Generated Ballast Water: Gray Water Investigation
U.S. Coast Guard New London
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This report describes a study conducted to examine the feasibility of gray water ballasting on cruise ships andrelated corrosion issues. Mass loss and electrochemical corrosion experiments were performed on A36 steelcoupons with simulated gray water treated and untreated, seawater, and mixtures of gray water and seawater.The seawater samples had a greater corrosion rate in grams per square meter per day gmm2day than the graywater samples, however, trends for the other types of grayseawater mixtures differed between the two experimentalmethods. Corrosion rates for the electrochemical study were approximately 3-5 times greater than that for the massloss study, primarily because the electrochemical tests measured initial corrosion rates only, and the mass loss rateswere overall rates over 50 days.