Boiler water treatment and cleaning all boilers operate on the common premise that heat is transferred to water to create steam which is then used to do work onboard. the water used onboard, for whatever purpose, comes primarily from the sea. in order for seawater to be safely used for steam production, the salts and other contaminants must be removed from the water to minimize scale formation and corrosion in boiler water and steam circuits. mechanical and chemical technology is used in combination to do both. an evaporator or distiller is generally installed for the purpose of purifying the water until it contains only trace levels of minerals. seawater also contains dissolved gases which have been absorbed from the air or formed by decaying organic matter. they can be mechanically removed by deaeration, thermally reduced by increased feedwater temperature and/or chemically scavenged. an effective water treatment program minimizes scale and corrosion in the boiler system. since distillation and mechanical/thermal deaeration cannot remove all of the contaminants, routine chemical treatment programs are necessary for the efficient maintenance of all steam generating and cooling system equipment. distillation, ion exchange, and reverse osmosis (ro) are processes which may be used for the desalination of seawater.