A washing station for washing flexographic plates with water-based washing liquid, wherein said washing station comprises: - a chamber in which said plates are treated; - brushing means for brushing said plates arranged in said chamber; - a treatment unit for treating the water-based washing liquid used in or by the washing station , wherein said washing liquid comprises some monomer or polymer detached from said plates during their washing, the treatment unit comprising: - a first tank for collecting said washing liquid to a predetermined minimum filling level (L1), said monomer or said polymer surfacing in said first tank after said liquid rests for a predetermined interval of time; - a second tank for collecting said monomer or said polymer surfaced in said first tank , wherein said second tank comprises an inlet section arranged at a lower height (H1) than said minimum filling level (L1) of said first tank , characterized in that - said first tank and said second tank of the treatment unit are arranged outside said chamber ; - the treatment unit comprises barrier means , movable between a closing position, in which said barrier means prevent the communication between said first tank and said second tank and an opening position, by effect of which said two tanks become communicating so that at least said monomer or said polymer surfaced in said first tank can overflow into said second tank ; - the washing station comprises a hydraulic distribution line comprising at least one circulation pump which hydraulically connects said first tank of said treatment unit to hydraulic terminals inside said chamber , from which said washing liquid may exit. - a chamber in which said plates are treated; - brushing means for brushing said plates arranged in said chamber; - a treatment unit for treating the water-based washing liquid used in or by the washing station , wherein said washing liquid comprises some monomer or polymer detached from said plates during their washing, the treatment unit comprising: - a first tank for collecting said washing liquid to a predetermined minimum filling level (L1), said monomer or said polymer surfacing in said first tank after said liquid rests for a predetermined interval of time; - a second tank for collecting said monomer or said polymer surfaced in said first tank , wherein said second tank comprises an inlet section arranged at a lower height (H1) than said minimum filling level (L1) of said first tank , - a first tank for collecting said washing liquid to a predetermined minimum filling level (L1), said monomer or said polymer surfacing in said first tank after said liquid rests for a predetermined interval of time; - a second tank for collecting said monomer or said polymer surfaced in said first tank , wherein said second tank comprises an inlet section arranged at a lower height (H1) than said minimum filling level (L1) of said first tank , - said first tank and said second tank of the treatment unit are arranged outside said chamber ; - the treatment unit comprises barrier means , movable between a closing position, in which said barrier means prevent the communication between said first tank and said second tank and an opening position, by effect of which said two tanks become communicating so that at least said monomer or said polymer surfaced in said first tank can overflow into said second tank ; - the washing station comprises a hydraulic distribution line comprising at least one circulation pump which hydraulically connects said first tank of said treatment unit to hydraulic terminals inside said chamber , from which said washing liquid may exit. <EOS>