During the month of December, the commissioning of the Masia de Perafita wastewater treatment plant was completed, a project commissioned by the Osona County Council. The wastewater originates from the Can Garriga urbanization (Seva, Barcelona), with an equivalent population of 471 inhabitants. The biological treatment defined in the project uses Rotating Biological Contactors (CBR) due to their lower energy and operational costs. The design flow rate is 120 m³/day.

The treatment plant includes a fine screen at the inlet and a water accumulation tank that receives excess sludge recirculation from the lamellar settler. A scoop wheel lifts the water to the first biological contactor. The facility has two biological contactors in series, and at the outlet, another scoop wheel lifts the water to the lamellar settler. The discs have a diameter of 2.5 meters, and each line contains 220 smooth discs on which the biomass forms. The rotation shaft is made of stainless steel and driven by a 1.5 kW motor, rotating at 3.5 rpm. The movement of the discs in and out of the water allows for biomass aeration. A timed pump recirculates sludge from the settler back to the inlet tank. All modules are enclosed under aluminum covers.

Once hydraulic and electrical tests were completed, the treatment of wastewater began, and during December, it was certified that the treated effluent met quality parameters for COD, BOD, and ammonia.

CBR technology wastewater treatment plants are noted for their environmental sustainability, offering high purification performance with minimal energy consumption, and a very low environmental impact in terms of noise, odor, and landscape.