To provide a drain treatment device capable of effectively utilizing an
ammonia component of an
ammonia-containing drain recovered from a
fuel injection system of a marine
diesel engine.SOLUTION: A drain treatment device, which is one embodiment of the present invention, includes: a
recovery part which communicates with a
fuel injection system for spraying
ammonia fuel and
fossil fuel into a
combustion chamber of a marine
diesel engine, and which recovers an ammonia-containing drain discharged from the
fuel injection system; and a supply part that supplies an ammonia component, included in the recovered ammonia-containing drain, to one or more functional parts functioning by utilizing the ammonia component.SELECTED DRAWING: Figure 1