Agenda Packets - 2008/07/28 - Laserfiche WebLink

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Item No. 07G Meeting Date: July 28, 2008 Type of Business: CB City Administrator Review _______ City of Mounds View Staff Report To: Honorable Mayor and City Council From: Steve Dazenski, Parks/ Public Works Supervisor Item Title/Subject: Resolution No. 7308 Approving the Purchase and Installation of a Grinder Pump at Groveland Lift Station. Background: The pumps at Groveland Lift Station, located at 2815 Ardan Avenue, were repaired in 2001 as a preventative maintenance procedure. In the following six-plus years the pumps have again become worn and the tolerances are no longer within recommended manufacturer specifications. In addition, the lack of a grinder within the wet well allows bulk material (i.e. rags, diapers, condoms, sanitary napkins etc.) to pass through and become lodged in the pump causing further wear on the motors. Discussion: Due to the worn tolerances the pumping capacity is less than 80% of pumping efficiency. This causes either both pumps running unnecessarily at the same time or one pump running double time. Also, due to the worn tolerances the aforementioned materials become lodged causing motor wear and forcing utility workers to enter the dry well confined space to remove the material. The estimated time spent removing the material is between 120-150 hours annually. The estimated cost of this labor is between $5,280-$6,600 annually. The loss of one pump has become commonplace in the last six-plus years, this routinely occurs on weekends when no one is available to read the pumping reports. As things stand right now, the best case scenario is that the City relies on the pumps to alternate when one is shut down. In a worst case scenario, the loss of both pumps would cause severe sewage back-up into the basement of households in the vicinity. Recommendation: Staff has extensively researched solutions to rectify the problems with Groveland Lift Station. Three specialists within the pump industry (Braun and General Repair Service and Electrical Pump), have been on site to inspect the pumps and give their recommendations. Both conclude that the pumps at Groveland Lift Station are in need of repair and/or replacement or modification. General Repair Service quotes a price of $13,000+ to repair the pumps and $17,000+ to replace them. This will bring the pumping capacity back to 100% but does not ensure elimination of bulk material being lodged in the pumps.