This European Standard specifies general requirements for structures and equipment as they relate to wastewater treatment plants for a total population of more than 50 PT. The primary application is designed for wastewater treatment plants for the treatment of domestic and municipal wastewater. Requirements for structures which are not specific for wastewater treatment plants are not within the scope of this European Standard. Other ENs can apply. Equipment which is not solely used in wastewater treatment plants is subject to the applicable product standards. However, specific requirements for such equipment when used in wastewater treatment plants are included in this part. General principles of building construction, mechanical and electrical engineering are not subject of this standard. This European Standard does not cover the design of treatment processes. Differences in wastewater treatment throughout Europe have led to a variety of systems being developed. This standard gives fundamental information 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 Bibliography.