This part of this European Standard specifies the requirements for preliminary treatment of wastewater at wastewater treatment plants for over 50 PT. The primary application is for wastewater treatment plants designed for the treatment of domestic and municipal wastewater. Preliminary treatment may include one or more of the following options: - screening; - grit removal, - grease separation; - flow balancing and flow separation. NOTE Flow measurement and/or sampling provision may be included with any of the chosen options. Differences in wastewater treatment throughout Europe have led to a variety of systems being developed. This standard gives fundamental informations about the systems; this standard has not attempted to specify all available systems. Detailed information additional to that contained in this standard may be obtained by referring to the bibliograpy.