333 S. Meridian, Puyallup, WA 98371 - 253-841-4321

City of Puyallup

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AI- 3682   3.    
City Council Agenda
Meeting Date: 06/04/2013  
Subject:    Water Pollution Control Plant Protective Coating Project
Presenter: Don Lange
Department: Public Works  

Recommended Action
Authorize the City Manager to sign a contract with Cherokee Construction Services, LLC for $326,996.60 in a form approved by the City Attorney for services applying protective coatings to the Water Pollution Control Plant (WPCP) four influent screw pumps, four screw pump channels, secondary clarifier #2, and secondary clarifier #2 launderer.
One or more of the influent pumps operate 24/7 pumping wastewater from the entire City of Puyallup. Three of the four screw pumps have been in service for 30 years. The fourth pump was installed in 2000 when odor control covers were added to all pumps. The effect of gases inherent in wastewater are exacerbated by the odor control covers resulting in sulfurous and mild sulfuric acid. These compounds are corrosive to steel and concrete. For protection, specialized coatings must be periodically applied. A manufacturer's inspection report of the pumps in 2012 stated that  two of the four pumps (#3 and #4) will likely fail within the next four to five years if not coated. The pumps and their respective channels were last coated in 2007. Although not operating in as harsh an environment as the screw pumps, the rotating flight mechanism of No. 2 Secondary Clarifier was last coated when installed in 2000. The concrete launderer (discharge channel) for the secondary clarifier needs coating to prevent erosion and spalling.

Formal bids were solicited for this project. Seven bids were received, with the bid amounts ranging from $326,996.60 to $662,362.30. The engineer's estimate for the project was between $300,000 - $400,000.
Previous Actions (Discussions/Presentations)
All four screw pumps were last recoated in 2007. The Secondary Clarifier No.1 rotating mechanism and launderer channel were coated in 2010. The Secondary Clarifier #2 has not been coated since its initial installation in 2000. Our experience indicates that the screw pumps need to be recoated at intervals of five to seven years, depending upon the durability of the coating.
Summary of Proposal
The specifications require that each of the four 47' screw pumps be removed from their channels (two at a time), sandblasted and cleaned, coated with specialzed protective materials, and then reinstalled along with new deflector plates provided by the City. Each screw pump channel must also be cleaned and coated with an approved protective material. Secondary Clarifier No. 2 will be drained of water and the approximately 110' rotating flight mechanism will be sandblasted and coated in place as will the effluent launderer.
The alternative would be to do nothing, allow the pumps to deteriorate beyond repair and budget for their replacement in about 2017. The new pumps would be coated at the factory but the channels in which they operate would need repair and coating at that time. We estimate the cost of replacing the pumps and coating the channels to exceed $600,000.

Fiscal Impact
Amount Budgeted: $400,000.00
Bid Amount: $326,996.60
City Funding Needed for Project: $326,996.60
Funds from Other Sources: Sanitary Sewer Fund
Ongoing Staff Costs: n/a
Fiscal Impacts:
This project was identified and approved in the 2013 Sewer CIP budget. Funds are available in the Sewer Fund.
Water Pollution Control Plant Protective Coating Project Bid Summary

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