03/23/1998 Council Packet - Laserfiche WebLink

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AGENDA ITEM 5C STAFF ORIGINATOR: David Ahrens, City Engineer /Public Works Director DATE: January 26, 1998 TOPIC: Resolution No. 98 -28, Order Improvement, Approve Plans and Specifications and Authorize Advertisement for Bids, Blackduck Drive Lift Station BACKGROUND: On January 26, 1998, council ordered the preparation of plans and specifications for the construction of a new lift station on Blackduck Drive. The plans and specifications are complete and staff is requesting Council approval and authorization to advertise for bids. The lift station construction is planned to coincide with the Lakes Addition Street Reconstruction Project to minimize construction activity within the neighborhood and to replace a deficient lift station. The existing lift station consists of a wet well to store the waste water connected to a separate dry well that houses the pump and fittings. This design requires maintenance personnel to enter the dry well to work on the pumps. Work in this confined space requires special safety precautions to meet OSHA rules: The waste water flow volumes that enter the existing Blackduck Drive lift station have exceeded its capacity and in order to keep up with the higher flow volumes, the pump cycles at an extremely high rate (15 times per hour) with the pump on for a very short time (30 seconds), This high cycle frequency contributes toward excessive wear on the pumps. Recommended cycle times for a lift station are 6 cycles per hour. The small storage volume within the wet well not only contributes to a high cycle frequency but also reduces the storage volume and time lag to respond to pump failures prior to the flow backing up into a basement. Staff is proposing to construct a new lift station consisting of a wet well and submersible pumps on the east side of Blackduck Drive within the unimproved Captains Place right of way. This will allow the existing lift station to remain in service as the new one is constructed. The new design will also eliminate the unsightly pump house as all of the components of the new lift station will be underground except for a control panel. The pumps from the existing lift station will be placed in the new lift station saving on some of the costs.