Section 602.310  Projects Requiring Disinfection

a)         Wells, water storage tanks, water treatment plants, and water mains must be disinfected in accordance with AWWA C651, C652, C653, or C654, incorporated by reference in 35 Ill. Adm. Code 601.115.

b)         Disinfection of a filter with granular activated carbon (GAC) must be completed before adding the GAC.  Disinfection of an ion exchange unit must be completed before adding a resin with a low chlorine tolerance.  Disinfection of a membrane unit must be completed before adding membrane material with a low chlorine tolerance.  Care should be taken when handling the GAC, resin, or membrane to keep the material as clean as possible.

c)         Except as provided in Section 602.315, the permit applicant must verify disinfection before seeking an operating permit-by-rule under Section 602.235 or the issuance of an operating permit by the Agency for completed construction projects.  Disinfection is verified when two consecutive water sample sets collected from the completed project at least 24 hours apart show the absence of coliform bacteria and the presence of a chlorine residual as required by 35 Ill. Adm. Code 604.725.  A sample set consists of the following:

1)         For water mains, representative water samples must be collected from every 1,200 feet of new main along each branch and from the end of the line.  The Agency may approve a different sampling plan on a site-specific basis.

2)         For water treatment plants, representative water samples must be collected from each aerator, detention tank, filter, ion exchange unit, and clearwell, from all other treatment components other than those not requiring disinfection under Section 602.315, and from the entry point to the distribution system.

d)         Analyses conducted under this Section must be performed by a certified laboratory.

(Source:  Amended at 47 Ill. Reg. 7449, effective May 16, 2023)