Abstract
In recent years, industrial waste matters and wastes which are discharged from daily life have become enormous in quantity and disposed volume of these wastes to the seas are abruptly increasing. As the result, the demolition of natural environment has been expanding to the seas.
In such condition, the counterplot should be considered as a world-wide, important problem.
Under the fact that control of waste discharging of the ships to the seas has been intensified ever more, it is necessary to have a sewage treatment plant on board which conform to the rule requirement.
In the paper, information on treatment plants concerning sewage are dealt with, that is, Type, Characteristic, Construction, etc. (i.e. holding tank, discharge type, non-discharge type) and also requirements from various regulatory agencies such as Japanese Government, IMCO and U.S.C.G.
