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<br />Bar screen channels need to be empty to allow demolition of the existing channels and <br />subsequent replacement with new channels. Wastewater flow needs to be bypassed around <br />the flow channel that is under renovation. <br /> <br />Flow would be routed into the existing grit tank until completion of the new grit system. <br />Once complete, flow would be routed into the new grit system while the existing grit tank is <br />demolished. <br /> <br />Northem Dewatering, Inc. provides bypass pumping, and evaluated bypassing wastewater <br />flow at the Elk River WWTF ITom the influent force mains to the primary clarifiers. A <br />temporary wet well with adequate reservoir capacity is needed for Northern Dewatering to <br />provide bypass pumping effectively and safely using grinder pumps. Based on their <br />evaluation, the budget price for bypassing flow is $31,000 for the first month and $8,000 per <br />month after that. <br /> <br />RECOMMENDED ALTERNATIVE <br /> <br />Howard R. Green Company recommends upgrading the Elk River WWTF Headworks to <br />meet an average day flow of3.5 MGD and a peak hourly flow of 7.0 MGD. to meet the <br />flow demands, HRG proposes widening bar screen channels, replacing the existing bar <br />screens, providing conveyors and compactors to dispose of screenings in a small building <br />addition, installing a vortex grit tank, installing a primary clarifier splitter structure, <br />construction of a chemical building for phosphorus removal, and rerouting yard and process <br />piping to the upgrades. <br /> <br />To minimize costs, HRG proposes to use the existing building and modify as required. <br />Specific manufacturers may be required to meet the limited space in some cases. The items <br />listed below are recommended by HRG for specific process upgrades. <br /> <br />Screens: US Filter I Envirex bar screens fit into existing Pretreatment Building. <br /> <br />Grit Tank: One 7.0 MGD unit; several models are available for competitive bid. <br /> <br />Grit Pwnps: Several manufacturers available for competitive bid. <br /> <br />Screening Disposal: Multiple screw conveyors, compactor, building addition for screenings <br />disposal. <br /> <br />Grit Disposal: Dwnpster located inside the existing grit room. <br /> <br />Chemical Building: Chemical building and piping to flow splitters to meet future <br />phosphorus regulations. <br /> <br />13 <br />