Background/Discussion
On December 3, 2024 bids were received through the City bidding software Ion Wave as follows:
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Building Crafts, Inc., Red Oak, IA |
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$928,000.00 |
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Eriksen Construction Co., Inc., Blair, NE |
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$996,700.00 |
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Engineer’s Estimate (HDR) |
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$1,209,500.00 |
The centrifuge at the Water Pollution Control Plant (WPCP) is used to process digested sludge for bio-solids production. Centrifugal thickening and dewatering of sewage sludge is a high speed process that uses the force from rapid rotation of a cylindrical bowl to separate wastewater solids from liquid to produce a non-liquid material referred to as “cake.” Dewatering wastewater solids reduces the volume of residuals, improves operation, and reduces costs for subsequent storage, processing, and disposal.
The facility operates with one centrifuge, with a second model as back-up. Both existing centrifuges have manufacture dates from the mid-1990s, and are now having reliability issues. One was recently removed from service due to poor operation. The cost to repair the unit cannot be justified, given its age and obsolescence. The excessive unit vibration and noticeable wear has expedited the need for a replacement.
The replacement equipment will increase resiliency and sustainability of the treatment process. The new centrifuge will produce the same class of bio-solids and use the existing screw conveyor and polymer feed systems.
This project was included in the FY24 CIP, and project costs will be paid with Sewer funds and GO Bonds.
The project is scheduled to be complete by May 31, 2025.