Specifications include, but are not limited to: Dunn Reclaim Water and Reject Water Pond Liner Replacement: The existing liners for both reject and reclaim storage ponds have reached the end of their useful service. As part of the reclaimed water production system, the WRF uses a reclaimed water storage pond and a reject pond (for non-spec reclaimed water). The reject pond is used for temporarily storing effluent that does not meet reclaimed water standards and is sent back through the plant for further treatment. Both ponds were constructed with asphalt lined bottoms and an HDPE liner that extends from the asphalt bottom to the top of the embankment and terminates in an anchor trench. Both ponds’ HDPE liner systems have been in service for approximately 33 years. The HDPE pond liner inspection results conclude that liner degradation has occurred due to its age and exposure to UV light and heat, leading to depletion of antioxidants and stress cracking. The last inspection performed in 2011 concluded that the HDPE liner had an estimated ten years of remaining life but that a re-assessment should occur after five years. Although the County routinely inspects and performs maintenance on the liner, the number and frequency of repairs is increasing. Regular maintenance primarily includes identifying defects and making repairs to the areas accessible above the water elevation. Historically, the ponds have been drawn down minimally to make repairs below the normal water line but reducing the water level in the ponds significantly (i.e., especially the reclaimed water pond) is less common and takes considerably more planning and effort to accommodate.; Dunn Offsite Reclaim Pump Station Improvements: The purpose of this project is to provide a complete improvement of the reclaim water pump station. Work will include addressing all five (5) existing pumps: a) remove two (2) existing vertical turbine pumps and furnish and install two (2) 250 HP pumps, b) remove two (2) existing vertical turbine pumps and install two (2) 400 HP vertical turbine pumps furnished by the Owner, c) remove one (1) existing 400 HP vertical turbine pump and send to manufacturer/manufacturer’s representative for inspection – reinstall this pump with all new mechanical seals. Other work will include expanding the existing electrical building with replacement of electrical components including but not limited to: switchgear, motor control centers and variable frequency drives; provide SCADA improvements including new local control panel with programmable logic controller; furnish and install a backup diesel generator system, four new auto strainers, various flow meters and associated piping.
