Administration - Nick Fleischhacker, Deputy Director of Public Works
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Authorize a Design Contract with Barr Engineering for Project 23-21- Water Treatment Plant 1 System Improvements
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Executive Summary
Council is requested to approve a contract for professional design services with Barr Engineering for an underdrain design and an iron/manganese filter pilot study at Water Treatment Plant No. 1 (WTP 1), Improvement Project No. 23-21 in the amount of $116,000.00.
Background
City staff has been experiencing issues with incomplete backwashing of the filter media and reliability of the underdrain piping in the pressure filters at WTP 1, 2 and 3 over the years. In an effort to find a way to correct these issues, Barr Engineering performed a backwash reclaim study in December 2021 at WTP 1 and WTP 3. During the study it became apparent that there are inconsistencies with the existing filters including: filter vessel size, loading rate, backwash rate, backwash supply, control valve functionality, filter underdrain distribution piping, and filter backwash collection piping. The recent media change in the filters from Electromedia by Filtronics to pyrolusite resulted in an increase in backwash rates due to the denser pyrolusite filter media. That in turn has affected other plant system operations.
A plan was developed to complete an underdrain redesign and a full-scale pilot testing of alternative media to determine the achievable capacity and operational improvements that a wholistic media changeout and underdrain redesign could provide at WTP 1, 2, and 3. The goal was to complete this project first at WTP 3, which is the smallest of the pressure filter treatment plants, in 2023. The results of the pilot study and underdrain redesign work done at WTP 3 would then be utilized on WTP 1 and WTP 2 in future years as identified in the 5-year CIP. The 2023 Capital Improvement Plan (CIP), which has been approved by the City Council, identified this project at WTP 3.
Due to recent findings that WTP 1 is at greater risk, the pilot testing will be completed at WTP 1 first instead. Within the CIP, the program dollar amounts will remain within appropriations and the recommended detail within the treatment plant improvements program category will be shifted to reduce emergent risk.
Staff has requested a proposal from Barr Engineering for this proposed project. The scope of the work will generally consist of:
• Design a repair for the broken underdrain piping. It is anticipated that this design (or a variation) will be replicated at other WTPs as their filters are rehabilitated.
• Perform pilot and full-scale testing to evaluate and recommend modifications to resolve backwash and long-term reliability issues experienced at WTP 1, 2, and 3.
• Aid during procurement and installation of air stripper media.
The attached proposal details the Scope of Work and estimates the fees to prepare the documents. Barr Engineering is in the council approved engineer consultant pool. Staff has reviewed this proposal and determined that the fees are justified and reasonable.
Strategic Plan Relationship
This project aligns with the City’s strategic plan goal of well-maintained infrastructure by providing high quality drinking water. This action relates directly to the City of Blaine Strategic Plan Item No. 6 - Well Maintained Infrastructure and Desired Outcome - Reliable Utility Systems. This work will improve the conditions of Water Treatment Plant 1 to meet the system demands and maintain the quality of the City’s infrastructure.
Board/Commission Review
Not required.
Financial Impact
The design contract attached is $116,000.00; staff recommends a 10% contingency for the contract to bring the total project budget to $127,600.00. The total budget appropriated to date for water treatment plant improvements is $3 million; the total project budget is $5.6 million. The current appropriated budget is adequate to cover the contract cost.
Public Outreach/Input
None required.
Staff Recommendation
By motion, authorize the Mayor and City Manager to enter into a contract with Barr Engineering in the amount of $116,000. In addition, authorize a 10% contingency to bring the total project budget to $127,600.00 and authorize the City Manager or their designee to sign all change orders up to the authorized project budget amount.
Attachment List
Barr Engineering WTP 1 Underdrain Design and Iron/Manganese Filter Pilot proposal