The Defender® compact pre-treatment plant is a complex equipment that allows the implementation of several processes simultaneously: straining, removal of sand and grease. These facilities include a channel screen conveyors or compacting auger, 2 pcs. screw conveyor (longitudinal and inclined), sand and grease removal bath-tub and scraper system. Once the solids have been filtered, compacted and removed, the equipment is equipped with a fine aeration system located at the bottom of the bathtub, which allows the fat to rise to the surface. The grease is then removed by a scraper trapping system located at the end of the sand and grease removal bath-tub, which transports it to the edge of it from where it is gravitationally extracted by pipe.