Attachment_0004__AWWA_Standard.pdf

This is an ANSI/AWWA C652-11 standard document titled "Disinfection of Water-Storage Facilities," which prescribes minimum requirements for disinfecting water storage tanks used in potable water systems.

The standard applies to newly constructed water storage facilities and those taken out of service for inspection, repair, painting, cleaning, or other maintenance activities that could cause water contamination. It describes three primary chlorination methods: (1) filling the facility to overflow level with chlorinated water at not less than 10 mg/L free chlorine residual and maintaining for 6 or 24 hours depending on application method; (2) spraying or painting water-contact surfaces with a 200 mg/L chlorine solution and maintaining contact for at least 30 minutes; and (3) a two-step process using 50 mg/L chlorine in the bottom portion for 6 hours, followed by filling to overflow while maintaining at least 2 mg/L free residual for 24 hours. Acceptable chlorine sources include liquid chlorine (conforming to ANSI/AWWA B301), sodium hypochlorite (ANSI/AWWA B300), and calcium hypochlorite (ANSI/AWWA B300). The standard requires water quality sampling and testing for coliform bacteria and chlorine residual per Standard Methods for the Examination of Water and Wastewater before facilities are placed in service. Section 4.4 establishes detailed requirements for underwater inspection and cleaning operations, including pre-job meetings, equipment specifications, personnel qualifications (such as 2nd Class US Navy Diver Training or ANSI/ACDE 01 Commercial Diver Certification), OSHA Confined Space Certification, safety protocols, and comprehensive disinfection of all equipment and personnel prior to tank entry. The appendices provide supplementary information on chlorine residual testing methods, dosage calculations for various chlorine concentrations and volumes, and disposal procedures for highly chlorinated water.