One of WEF's Manual of Practice series, Operation of Extended Aeration Package Plants (MOP OM-7) describes the typical treatment processes of small package extended aeration wastewater treatment plants. This manual covers many important aspects of this variation of the activated sludge treatment process, from installation of prefabricated treatment plant packages to operation of the process, tests and maintenance, adhering to regulatory requirements, and safety and health considerations. Operation of Extended Aeration Package Plants (MOP OM-7) is a valuable guide for the individual who is operating a treatment plant with a design flow of up to 5 L/s (100 000 gpd).