Phytodepuration plants for soil discharge consisting of imhoff tanks and grease separators and phytodepuration trays. Phytodepuration treatments are made of polyethylene and are intended for the treatment of domestic wastewater. Treatments involving discharge in tab. 4 are normally sized with 1 tray per inhabitant equivalent. This allows for a refinement of the effluent in accordance with more stringent tabular limits.