This document specifies design principles and performance requirements for tertiary clarification (receiving effluent from secondary treatment) by physical filtration plant at wastewater treatment plants serving more than 50 PT. NOTE 1 – Ultrafiltration, nanofiltration and reverse osmosis are not covered within the scope of this document as they are not considered to be used for tertiary clarification. NOTE 2 – Soil filtration is not covered in this document. NOTE 3 – Activated carbon filtration is excluded from the scope of this document as it is not considered to be a form of mechanical filtration.