To solve a problem that complicated constitution such as a filtering device and a distillation device, and a large amount of fuel are required for extracting only a deicing fluid through filtering and distillation for reuse or incineration, since a waste liquid includes the deicing fluid above a standard value after ice is melted and removed by spraying or blowing the deicing fluid onto an aircraft at an airport, in a cold district to prevent extreme deterioration of aerodynamic performance of the aircraft due to adhesion of the ice to a wing of the aircraft.

The water content excluding the deicing fluid in the waste liquid in which water melted from ice and the deicing fluid are mixed is mainly frozen by a freezing/concentrating device, the deicing fluid is recovered, and the frozen water is melted and discharged to a sewage so that the recovered deicing fluid can be reused or disposed.