This document specifies the design requirements for plant and equipment to remove solids, other than screenings and grit, from raw wastewater, at wastewater treatment plants for over 50 PT. It includes primary treatment with sedimentation, fine screens and micro-screens NOTE 1 The removal of screenings and grit, are covered in EN 12255, Part 3. NOTE 2 Dissolved air flotation (DAF) is not covered in detail in this document because it is not commonly used for primary treatment in municipal wastewater treatment plants. It may be used for primary treatment of industrial wastewater, but then the design is specific to the application.