Specifications include, but are not limited to: The work will include, but not be limited to, furnishing all labor, tools, select materials and performing all operations in connection with the Pyramid Water Treatment Plant ‐ SODIUM HYPOCHLORITE ON‐SITE GENERATION. The project replaces the existing gaseous chlorine dosing system with a new hypochlorite generation equipment. The City is providing the hypochlorite generation equipment, air blowers, water softener systems, brine tanks, hypochlorite tanks, dosing pumps, piping, instrumentation, electrical and other materials. The contractor is to supply select materials and install the hypochlorite generation equipment with all the interconnecting piping, tanks, valves, wires, and miscellaneous fittings necessary for a fully functioning system.; DISINFECTION OF POTABLE WATER PIPING: Water quality testing: Contractor shall perform water quality testing of water samples taken in the presence of an owner’s representative from the piping systems for chlorine concentrations and bacteriological quality. Unalaska DPW will approve use of disinfected piping when test results demonstrate compliance with water quality requirements of the Safe Drinking Water Act as described in Section 1.4 C, furnishing disinfection report to Contractor.; 1. Protect interior of pipes, fittings, and valves against contamination during construction; a. Material delivered for construction shall be protected so as to minimize entrance of foreign material.; b. Close opening of pipeline when pipe-laying is stopped at the end of the workday or for other reasons, such as breaks.; 2. Do not disinfect any pipe until source of potable water supply used for flushing or disinfection is approved by Unalaska DPW.; 3. Contractor shall perform water quality testing of water samples taken from piping systems for chlorine concentrations and bacteriological quality as described in Section; 1.4 C. Samples shall be taken only when an owner’s representative is present. Lab reports shall be submitted to the owner with witnesses listed on report along with date, time, and location of sample.; DISINFECTION OF NEW WATER MAINS: A. Preliminary Flushing: 1. Prior to disinfection, fill main with water to eliminate air pockets.; 2. Flush new mains, including fire service mains and lead-in connections to fire system risers, thoroughly before connection is made to system piping in order to remove foreign materials that might have entered the main during the course of the installation or that might have been present in existing piping.; 3. The minimum rate of flow shall greater than the water demand rate of the system, which is determined by the system design. ; B. Chlorination of the Main: 1. Inject chlorinated water, with a free chlorine concentration of not less than 25 mg/L, into main at a point no more than 10 feet downstream from beginning of new main. Verify free chlorine concentration of not less than 25 mg/L by an initial free chlorine concentration test as described in Section 1.4 C.; 2. Leave chlorinated water in the main for at least 24 hours during which time valves and hydrants in system shall be operated to ensure disinfection of the appurtenances.; 3. At the end of the 24-hour period, treated water in all portions of the main shall have a free chlorine concentration of not less than 10 mg/L. Verify this by a residual free chlorine concentration test as described in section 1.4 C.
