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6.1.E. - Page 25 <br />NOTICE INVITING BIDS <br />RECYCLED WATER TANK WATER QUALITY CONTROL SYSTEM <br />CITY OF REDWOOD CITY, CALIFORNIA <br />BID SPECIFICATION <br />BACKGROUND <br />The City of Redwood City's Public Works Services Department is looking to improve water quality <br />in two recycled water storage tanks by installing a comprehensive water quality control system. The <br />system must have a mixer, controller, sensors, chemical pump skid, and chemical storage equipment. <br />The system must be designed to continuously monitor disinfectant levels in the storage tanks and <br />precisely dose chlorine to maintain a desired disinfectant concentration target. All equipment must <br />integrate to work as a complete system with the ability to maintain an established chlorine residual (5 <br />ppm). All water quality and dosing data should be logged and available for easy download. The <br />system must also integrate with SCADA. <br />Tank specifications are provided below. The tanks are adjacent, share an inner wall and are served <br />from the same power supply. Each tank is supplied through a separate 36" inlet manifold located in <br />the center of the south-east wall, and has one 30" outlet; in Tank 1 the outlet is offset from the center <br />of the tank, in Tank 2 the outlet is close to the center of the tank. <br />TANK INFORMATION <br />Tank ID <br />Address <br />Type <br />Volume [MG] <br />Diameter [ft] <br />Height (floor to roof) [ft] <br />High water line (bottom tank to overflow) [ft] <br />Inlet / Outlet [inches] <br />Recycled Water Storage Tanks 1 & 2 <br />1402 Radio Rd., Redwood City, CA <br />Partially In -Ground (18' of total below grade) <br />2.18 ea. <br />Rectangular 146' x 100' <br />24' - 3" <br />20' <br />Separate inlet and outlet <br />Inlet: 36" diameter ea. <br />Outlet: 30" diameter ea. <br />Power Supply Grid power available (115V and 230V) <br />Power supply is adjacent to the pump control room <br />Proposed System Location TBD (on roof or next to accumulator tanks) <br />• Available locations for chemical injection potable fill air -gap, access hatches, or vents <br />lines and power into tank <br />• Available location for sample port location Peristaltic pump <br />Sampled water Drain to sewer treatment plant (no dechlorination <br />required) <br />No cathodic protection <br />Notes <br />Recycled water has average ammonia levels of 25- <br />30 ppm and can peak around 45 ppm <br />Target chlorine residual is 5 ppm in the tank <br />NOTICE INVITING BIDS <br />2016-2017 RECYCLED WATER TANK WATER QUALITY CONTROL SYSTEM 8 of 16 <br />