SECTION 252:626-9-13. Stabilization and corrosion control

(a)   Stabilization and corrosion control. Make provisions for corrective treatment of waters that are corrosive to distribution systems and plumbing. The use of lined and coated mains in accordance with the AWWA standard specifications will minimize corrosion of the distribution system but will not protect plumbing systems on private property.

(b)   Equipment. Equipment for feeding of an acid, alkali or polyphosphate compound must comply with OAC 252:626-11.

(c)   Control procedures. Include specifications for stability control equipment and laboratory equipment for determining the alkalinity and pH of the water.

(d)   Stabilization of alkaline (high pH) water. Stabilization with carbon dioxide or acid must conform to one or more of the following:

(1)   Carbon dioxide addition.

(A)   Design recarbonation basin to provide:

(i)   a total detention time of twenty minutes, and

(ii)   two compartments, each with a depth of 8 feet, as follows:

(I)   a mixing compartment having a detention time of at least 3 minutes,

(II)   a reaction compartment.

(B)   Take adequate precautions to prevent the possibility of carbon monoxide entering the plant from the recarbonation compartments.

(C)   Make provisions for draining the recarbonation basin and removing residuals.

(2)   Acid addition. Take adequate precautions for safety, such as not adding water to the concentrated acid.

(e)   Polyphosphate addition. Polyphosphate addition for sequestering calcium in lime-softened water, and in conjunction with alkali feed following ion exchange softening must comply with the following:

(1)   phosphate chemicals must be listed by NSF or the FDA as food grade,

(2)   do not exceed 10 mg/l total phosphate applied as PO4,

(3)   keep stock phosphate solution covered and disinfected by carrying approximately 10 mg/l free chlorine residual, and

(4)   maintain satisfactory chlorine residuals in the distribution system when phosphates are used,

(f)   Carbon Dioxide Reduction. Carbon dioxide content of an aggressive water may be reduced by aeration. Aeration devices shall conform with OAC 252:626-9-3.

(g)   Other treatment. Other treatment for controlling corrosive waters by the use of sodium silicate may be used where necessary. Any compound must be approved by the DEQ before use.

[Source: Added at 18 Ok Reg 1612, eff 6-1-01; Amended at 25 Ok Reg 2304, eff 7-11-08]