The Gross Pollutant Trap (GPT) will capture silt, solids and hydrocarbons for later removal by an authorised waste contractor. The Gross Pollutant Trap (GPT) comes standard with a by pass outlet for overflow when the silt basket is full of litter. The removable silt basket and grate makes the Gross Pollutant Trap (GPT) quick and easy to clean. The lightweight but sturdy construction and quick connect options means easy installation. Grates area available in both B and D ratings.