Idaho Administrative Code
Title IDAPA 58 - Environmental Quality, Department of
Rule 58.01.08 - IDAHO RULES FOR PUBLIC DRINKING WATER SYSTEMS
Section 58.01.08.522 - FACILITY AND DESIGN STANDARDS: SURFACE WATER TREATMENT: FILTRATION USING DIATOMACEOUS EARTH
Current through August 31, 2023
The use of these filters may be considered for application to surface waters with low turbidity and low bacterial contamination, and may be used for iron removal for ground waters providing the removal is effective and the water is of satisfactory sanitary quality before treatment. (3-24-22)
01. Conditions of Use. Diatomaceous earth filters are expressly excluded from consideration for the following conditions: (3-24-22)
02. Treated Water Storage. Treated water storage capacity in excess of normal requirements shall be provided to allow operation of the filters at a uniform rate during all conditions of system demand at or below the approved filtration rate, and guarantee continuity of service during adverse raw water conditions without by-passing the system. (3-24-22)
03. Number of Units. A minimum of two (2) units for redundancy shall be provided for filtration such that plant design capacity can be maintained with any component out of service for maintenance or repairs. (3-24-22)
04. Precoat. A uniform precoat shall be applied hydraulically to each septum by introducing a slurry to the tank influent line and employing a filter-to-waste recirculation system. (3-24-22)
05. Body Feed. A body feed system to apply additional amounts of diatomaceous earth slurry during the filter run is required to avoid short filter runs or excessive head losses. (3-24-22)
06. Filtration Requirements. (3-24-22)
07. Backwash. A satisfactory method to thoroughly remove and dispose of spent filter cake shall be provided. (3-24-22)
08. Appurtenances. The following shall be provided for every filter: (3-24-22)
09. Monitoring. A continuous monitoring turbidimeter with recorder is required on each filter effluent for plants treating surface water. (3-24-22)