WASTE WATER TREATMENT Black and/or Grey water flows by gravity or by vacuum into the ship's collecting tank or the tank of the HL-CONT Sewage Treatment Plant. At a preset level the HL-CONT will automatically start. Once the stop level is reached the plant will go into stand-by function. An a¡r-vent at the highest point in the pipe loop aerates the sewage to optimize oxidation.The Macerator M 3^ then cuts all solids into very small pieces, hence enlarging the total surface area of the sewage. A dosing IHf pump will inject Chlorine into the sewage before it enters the Mixing and Draining Pump....