Idaho Administrative Code
Title IDAPA 58 - Environmental Quality, Department of
Rule 58.01.08 - IDAHO RULES FOR PUBLIC DRINKING WATER SYSTEMS
Section 58.01.08.537 - FACILITY AND DESIGN STANDARDS: DESIGN STANDARDS FOR STABILIZATION

Universal Citation: ID Admin Code 58.01.08.537

Current through August 31, 2023

Water that is unstable due either to natural causes or to subsequent treatment shall be stabilized. The expected treated water quality shall be evaluated to determine what, if any, treatment is necessary. (3-24-22)

01. Carbon Dioxide Addition. (3-24-22)

a. Recarbonation basin design shall provide the following: (3-24-22)
i. A total detention time of twenty (20) minutes. (3-24-22)

ii. A mixing compartment having a detention time of at least three (3) minutes. (3-24-22)

iii. A reaction compartment. (3-24-22)

iv. The mixing and reaction compartments shall have a depth sufficient to provide a diffuser submergence of not less than seven and one-half (7.5) feet and no greater than the manufacturer's recommendation. (3-24-22)

b. Where liquid carbon dioxide is used, adequate precautions must be taken to prevent carbon dioxide from entering the plant from the recarbonation process. (3-24-22)

c. Recarbonation tanks shall be located outside or be sealed and vented to the outside with adequate seals and adequate purge flow of air to ensure workers safety. (3-24-22)

d. Provisions shall be made for draining the recarbonation basin and removing sludge. (3-24-22)

02. Phosphates. The feeding of phosphates may be used for sequestering calcium, for corrosion control, and in conjunction with alkali feed following ion exchange softening. (3-24-22)

a. Stock phosphate solution must be kept covered and disinfected by carrying approximately ten (10) mg/l free chlorine residual unless the phosphate is not able to support bacterial growth and the phosphate is being fed from the covered shipping container. Phosphate solutions having a pH of two point zero (2.0) or less are exempted from this requirement. (3-24-22)

b. Satisfactory chlorine residuals shall be maintained in the distribution system when phosphates are used. (3-24-22)

03. Split Treatment. Raw water may be blended with lime-softened water to partially stabilize the water prior to secondary clarification and filtration. Treatment plants designed to utilize split treatment shall also contain facilities for further stabilization by other methods. (3-24-22)

04. Water Unstable Due to Biochemical Action in Distribution System. Unstable water resulting from the bacterial decomposition of organic matter in water (especially in dead end mains), the biochemical action within tubercles, and the reduction of sulfates to sulfides shall be prevented by the maintenance of a free or combined chlorine residual throughout the distribution system. (3-24-22)

Disclaimer: These regulations may not be the most recent version. Idaho may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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