Microscreens are equipped with filter mesh having openings that range from 1 to 200 microns, although most applications utilize openings within a 15- to 60-micron range. Microscreens have been used in a variety of water and wastewater applications for more than thirty years. The backwash water is usually obtained from the screened microscreen effluent. A spray pipe header equipped with replaceable nozzles is located above the drum, directing a water spray through the mesh and into a backwash trough located inside the drum. Supplemental mesh cleaning will be required to reduce the clogging. Design and construction of the drum assembly and support frame varies among equipment manufacturers. There are several methods used to support the drum assembly. The drive sprocket is mounted on the output shaft of the reducer, and the driven sprocket is mounted to a stub or central shaft fixed to the drum.