Lessons from the “Living-Filter”: An in-reservoir floating treatment wetland for phytoplankton reduction prior to a water treatment works intake

•Living-Filter reduces soluble manganese, dissolved inorganic nitrogen and nitrites.•Chlorophyll-a efficiency removal is up to 45% during the first seven weeks.•Zooplankton numbers are stable within the rhizosphere compared to the water column.•Only Phalaris and Carex should be considered in future designs.•The potential of the Living-Filter as a pre-treatment process has been demonstrated.