Section 58.01.16.460 - FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER TREATMENT OR DISPOSAL FACILITIES: SCREENING AND GRIT REMOVAL01.Screening Devices and Comminutors.a. Screening, coarse or fine, or comminutors shall be required for all mechanical plants and shall be addressed for other types of plants. These facilities shall be designed for peak hourly flow. Multiple channels shall be provided and equipped with the necessary gates to isolate flow from any screening unit. Provisions shall also be made to facilitate dewatering each unit. The channel preceding and following the screen shall be shaped to minimize settling of solids.b. For mechanical plants with design average flow less than one million gallons per day (1 mgd), and where a single mechanically cleaned screen is used, an auxiliary manually cleaned screen shall be provided. Where two (2) or more mechanically cleaned screens are used, the design shall provide for taking any unit out of service without sacrificing the capability to screen the design peak instantaneous flows.02.Grit Removal Facilities. Grit removal and handling facilities shall be provided for all mechanical wastewater treatment plants. Consideration shall be given to possible damaging effects on pumps, comminutors, and other preceding equipment, and the need for additional storage capacity in treatment units where grit is likely to accumulate.Idaho Admin. Code r. 58.01.16.460