Photo 1: sludge accumulates and dries on the surface of the filters after intermittent loading of wastewater on the surface of the filter. The photo shows the facility 2 months after start of operations, later the plants will cover the entire surface and their roots will maintain permeability of the filter despite sludge accumulation. Photo 2: minderalised sluge with parts of the reed plants from a 1st stage filter after several years of operation. The sludge is fully mineralised and can be used in agriculture.