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REQUEST FOR PROPOSALS <br /> General ContractorlConstruction Manager Services for <br /> 0,713715W- <br /> Water Pollution Control Facility Expansion-Phase C <br /> negotiating an agreement with the City of Snohomish to treat wastewater that <br /> is currently treated at the Snohomish wastewater treatment plant. The City <br /> plans to make improvements to the WPCF in order to allow the plant to <br /> continue to comply with the NPDES Permit requirements. <br /> C. The major work elements to be performed under the contract include: <br /> 1. Phase Cl (Liquid Stream): <br /> a. Civil site work will include the removal of approximately <br /> 40,000 cubic yards of surcharge material, soil densification <br /> (installation of stone columns) for an area approximately 65 <br /> feet wide and 550 feet long, placement of piles to support <br /> new .buildings and structures, dewatering for excavations, <br /> installation of pipe and grading and paving. <br /> b. The Liquid Stream Improvements will include an additional <br /> Trickling Filter, modifications to the Trickling Filter Pump <br /> Station, expansion of the Solids Contact Basins, <br /> modifications to the Secondary Clarifier Influent Structure, <br /> addition of a third Secondary Clarifier, and installation of an <br /> additional effluent pump in the South Effluent Pump Station. <br /> c. The new Trickling Filter will be similar to the existing two <br /> Trickling Filters with a domed cover. One 125-hp pump and <br /> multiple flow control valves will be added to the existing <br /> Trickling Filter Pump Station. The Trickling Filter will be pile <br /> supported. The existing Solids Contact Basins will be <br /> expanded by approximately 50 percent. This structure will <br /> be a pile supported concrete structure connected to the <br /> existing Solids Contact Basins. Fine bubble diffused <br /> aeration will be provided in these basins along with an <br /> additional 100 hp centrifugal blower in the existing <br /> Operations Building. A third Secondary Clarifier will be- <br /> provided with an inside diameter of 105 feet and a sidewater <br /> depth of 16 feet. This will be pile supported. The new <br /> Secondary Clarifier will include a Return Secondary Sludge <br /> (RSS) Pump Station adjacent to the outer wall of the clarifier, <br /> similar to the existing units. A ventilation system will be <br /> provided to convey foul air from the new Trickling filter to <br /> expanded or modified Biofilters for odor treatment. A fifth <br /> City of Everett Page 6 April 16, 2012 <br /> Water Pollution Control Facility Expansion-Phase C 9 <br />