Longitudinal grit chamber PDRR

The degritting and degreasing scraper bridge for rectangular basin is used on medium and large size water treatment plants. The bridge consists of a mobile steel girder in standard section with walkway surface in galvanized grating, a couple of lateral trolleys in cold bent metal sheet suitably stiffened, a bottom scraping system, a couple of gear motors fitted on in correspondence of the bridge center line (one for the transmission of the bridge translation motion and the other one for the scrapers movement), suitable weirs, elements for collection and overflow of the oily and surface-active substances, electric control panel, festoon power supply line. The sand collection tank can be provided with a diffuser system for the aeration which facilitates the removal of the oil and grease and carries out a pre-aeration of the sewage. The bridge, during the going stroke of its alternate motion, collects and removes any oily floating material by means of a surface scraper while, during the return, it scrapes the sands gathered on the tank bottom. The surface scraper is controlled by means of mechanisms similar to those driving the bottom scraper. As preferred, the bridge can move on rubber wheel or on specific steel rails.