AGENDA INFORMATION SHEET
DEPARTMENT: Materials Management
ACM: Bryan Langley
AGENDA DATE: September 20, 2016
SUBJECT
Title
Consider adoption of an ordinance accepting competitive proposals and awarding a contract for the purchase of four (4) dry pit submersible pumps for Raw Wastewater Pump Station No. 2 located at the City of Denton Pecan Creek Water Reclamation Plant; providing for the expenditure of funds therefor; and providing an effective date (RFP 6152-Xylem Water Solutions, USA Inc. in the not-to-exceed amount of $226,851.24). The Public Utilities Board recommends approval (7-0).
Body
RFP INFORMATION
Hazen and Sawyer (Hazen) was retained to do the computational fluid dynamics (CFD) modeling of the flow patterns from the raw wastewater screen to the inlet of the raw wastewater pumps for the Raw Wastewater Pump Station No. 2 (RSPS2) located at the Pecan Creek Water reclamation Plant. Staff had noticed issues with vibration, noise and limited pumping capacity in the RSPS2 pumps. The CFD analysis showed the approach velocities to the pump suction bells were much higher than recommended by the Hydraulic Institute (HI) Standards, cross flow was visible under the wall across the suction bell of Pump No. 6, and there were signs of swirling flow near the suction bell of Pump no. 6 and No. 7 in particular. The combination of the above hydraulic and structural deficiencies created an inefficient and unsustainable pumping station. The contract with Hazen was amended by Council on April 5, 2016 to provide design services for the replacement of the existing worn out pumps and improve the flow pattern in the existing wet well to the pump inlets.
Request for Proposals to purchase the replacement pumps specified in the engineering design contract were sent to 61 prospective suppliers, including local suppliers. In addition, specifications were placed on the Materials Management website for prospective suppliers to download, and advertised in the local newspaper...
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