(a) After satisfactory completion of the pressure test, disinfect new potable water mains and existing mains that have required repair in accordance with C651 and as specified herein.
(b) General.
(1) Provide a superintendent experienced in the required procedures for disinfecting with chlorine.
(2) Obtain city's permission 48 hours prior to filling, flushing, and chlorinating of the water mains. City shall operate valves connected to the existing water system.
(3) Do not allow highly chlorinated water into the existing distribution system.
(4) If there is any question that the chlorinated discharge will cause damage to the environment, a reducing agent shall be applied to the water to neutralize the residual chlorine. Federal, state, or local environmental regulations may require special provisions or permits prior to disposal of highly chlorinated water.
(5) Perform disinfection and testing in presence of a representative of the city.
(c) Connection to existing system.
(1) Notify city 48 hours prior to making connections to the existing system. Thoroughly clean the existing water main exterior prior to the installation of tapping sleeves and corporation stops. Lightly dust with calcium hypochlorite powder the water main exterior and the interior surface of the tapping sleeve, and corporation stops.
(d) After satisfactory flushing of the main, disinfect by the injection of a chlorine solution. Induce chlorine in sufficient quantity to maintain a chlorine residual of at least 50 ppm throughout the system to be tested. Maintain the chlorine solution in the system for at least 24 hours.
(e) Valves and fire hydrants.
(1) Open and close valves on the mains being disinfected a minimum of three times during the chlorine contact period and a minimum of three times during flushing. Fire hydrants and other appurtenances should receive special attention to insure proper disinfection.
(f) For cut-in construction.
(1) Use the following procedures for disinfecting of the new installation and the existing main at the cut-in point in accordance with AWWA C651, Section 9:
a. Apply liberal quantities of hypochlorite, in the form of tablets, to the open trench.
b. Interior of new pipe and fittings and the ends of the existing mains shall be swabbed or sprayed with a one percent hypochlorite solution before installation.
c. Install a two-inch tap downstream of the work area. Tap shall be used for blowing off the main, or use the next fire hydrant downstream of the work area for blowing off the main.
d. Install a two-inch tap just upstream of the new installation. Control water from the existing system so as to flow slowly into the work area during the application of chlorine. After the line is thoroughly flushed, add chlorine solution at a concentration of 100 ppm by the continuous feed method and hold in the main for one hour.
e. Coordinate all cut-in work with the city.
(g) Prior to flushing, the free chlorine residual shall be a minimum of ten ppm. Flushing of the lines shall proceed until the lines contain the normal chlorine residual of the system.
(h) Test in the field for free chlorine residual.
(1) Sample location shall be the same as required for the bacteriological test samples.
(2) Immediately after injection of the chlorine solution. Sample shall have a chlorine residual as specified.
(3) Prior to flushing of the highly chlorinated water from the potable water system and a minimum of 24-hours after the initial injection of the chlorine. Sample shall have a minimum chlorine residual as specified.
(Ord. of 11-7-16; No. 10-16)