Officine di Trevi studied the Topfilter system to avoid the obstruction of the electric pump in hard conditions. The Topfilter is carried out with filtering pipes and can be used in landfills where water with solid filamentous sediment and leachate is present. If properly measured, installed and checked, the filters can be the good solution to contain the ordinary operating costs of the plant. The filters have a cylindrical stainless steel structure and a very big contact surface with the pumped liquid. At the ends of the stainless steel cylinder there are two shaped thermoplastic discs: the upper disc allows the insertion of the pump, M45-M70 series, inside the filter. The electric pump, equipped with the filter, can also be supplied with slope riser to facilitate the introduction in oblique wells. The suction fissures have been studied to optimise the passage of little bodies and particles. It is indispensable that the filter is free from sediments for at least 30% of the surface to grant a correct working of the electric pump with suction inside. The external Ø of the Topfilter cylinder is 170 mm; in the version with slope riser the maximum overall dimension is 255 mm. The Topfilter can work completely submerged in liquids with maximum temperature +85 °C.