Definition sand, gravel, cinder, or other heavy solid materials that are “heavier” (higher specific gravity) than the organic biodegradable solids in the waste water, that are abrasive and have to be removed to minimise wear on the downstream equipment of a waste water treatment plant Reference COM-Terminology Coordination, based on:1. 'Wastewater Technology Fact Sheet. Screening and Grit Removal', US Environmental Protection Agency http://water.epa.gov/aboutow/owm/upload/2004_07_07_septics_final_sgrit_removal.pdf [13.1.2016]2. 'Best Available Techniques (BAT) Reference Document for Common Waste water and Waste Gas Treatment/Management Systems in the Chemical Sector', Joint Research Centre (JRC), European Commission http://eippcb.jrc.ec.europa.eu/reference/BREF/CWW_Final_Draft_07_2014.pdf [13.1.2016]