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Water Treatment Plant #4

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Water Treatment Plant #4 returned to service

Early in 2019, Water Treatment Plant #4 (WTP4) returned to service providing water to St. Louis Park residents. Located at 4701 W. 41st St., the plant was taken out of service at the end of 2016 after testing showed that while some volatile organic compounds (VOCs) were being reduced by an implemented short-term treatment solution, others were still increasing. The city worked with the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health (MDH) to design and implement upgrades to treat all identified contaminants, regardless of their source, down to published advisory levels. The upgrades included adding two air stripper units to treat the VOCs found in the water at this plant as well as many other upgrades, primarily to the interior.

Project background

The city's has selected Municipal Builders Inc. (MBI) as the contractor for the project. MBI has a great reputation for constructing water treatment plants, and we look forward to working with them. The city also hired AECOM, a consulting firm, for the construction administration portion of the project. AECOM was the designer for the water treatment plant and will ensure the treatment plant is constructed following the plans and specifications.

In order to accommodate construction vehicles in the area, no parking signs were installed adjacent to the treatment plant. The location of no parking may change in the future, if needed.

Public meetings

  • An informational neighborhood meeting was held on Oct. 10, 2017 at city hall.
  • A public hearing was held by the planning commission on Oct. 18, 2017.
  • City council discussed the approval of a conditional use permit and variance at a Nov. 6, 2017 meeting.

Resources and documents

Previous project updates 

Nov. 20, 2017
Council voted 7-0 to designate Municipal Builders, Inc. the lowest responsible bidder and authorize execution of a contract with the contractor for the project. View the complete agenda and minutes from the meeting.

Nov. 6, 2017
The council approved a conditional use permit and variance at 4701 W. 41st St. The request is to make improvements to Water Treatment Plant #4.

The city requests a variance of 12 feet from the required 30 feet front yard setback requirement. The variance would allow mechanical equipment and a screening wall to be built 18 feet from the east property line.

September 2017 
The City of St. Louis Park has hired the consulting firm AECOM to complete the final plans and specifications for Water Treatment Plant #4. The Minnesota Pollution Control Agency (MPCA) has been working with AECOM on the redesign and has completed the design up to 90 percent. The city has received the 90 percent plans from the MPCA to complete the bid documents and prepare for construction. This project is included in the city’s Capital Improvement Program for 2017. Funding will be provided using General Obligation Utility Revenue Bonds in 2017 and 2018. Repayment of the bonds will be from the water utility enterprise. 

Sept. 20, 2017
Water Treatment Plant #4 Rehabilitation - Approve plans and specs and authorize advertisement for bids (Sept. 18, 2017, city council meeting). Motion to adopt resolution approving final plans and specifications, and authorizing advertisement for bids.(Motion approved 6-0)

Aug. 11, 2017
In August/September, prior to the start of the construction contract, some activity will be occurring at the plant as maintenance/repair work is conducted on the well itself. This maintenance work is not part of the treatment upgrades, but is being done to increase the efficiency of the well pump and motor. The city is also exploring the benefits of having a separate contractor remove the large carbon filter vessels prior to the start of the upgrade project. Removing these vessels before the start of the upgrade contract is expected to lower the costs and shorten the length of the overall project.

July 17, 2017
Approve consultant contract for Water Treatment Plant #4 (July 17, 2017, city council meeting)
Motion to authorize execution of a contract for professional services with AECOM in the amount of $332,900 for Water Treatment Plant #4.

June 5, 2017
Joint powers agreement with MPCA for Water Treatment Plant #4 design transfer (June 5, 2017, city council meeting)
Motion to authorize the mayor and city manager to execute the Joint Powers Agreement with the Minnesota Pollution Control Agency (MPCA) for the transfer of the 90 percent project design for Water Treatment Plant #4's treatment upgrade from the MPCA to the city.

Water Treatment Plant # 4 update (March 27, 2017, city council study session report)
The purpose of this report is to provide council with an update on the design and next steps for the permanent upgrades to Water Treatment Plant #4.

June 5, 2017
Below is an updated timeline for the design and construction of Water Treatment Plant #4, based on a June 5, 2017, council report. Please note these are anticipated dates and are subject to change. Some actions are the responsibility of outside agencies so not under city control, while other actions are subject to review by outside agencies that may impact dates. Unless otherwise noted, dates are in 2017.

  • April 14 — Minnesota Pollution Control Agency (MPCA) to provide draft 90 percent plans for review
  • April 25 — MPCA/Minnesota Department of Health (MDH)/St. Louis Park plan review/coordination meeting
  • May 1 — MPCA to provide amended 90 percent plans to MDH
  • June 30 — MPCA to submit MDH-approved plans to St. Louis Park (previously May 15)
  • July 31 — St. Louis Park engineering staff to complete drawings; prepare for advertising for bid (previously June 14)
  • Aug. 21 — Request to advertise for bid (council meeting) (previously July 3)
  • Sept. 18 — Request to award bid (council meeting) (previously Aug. 7)
  • Oct. 2 — Construction start (previously Aug. 14)
  • Fall 2018 — Construction complete

Jan. 31, 2017
The 90 percent design submission for Water Treatment Plant #4 that was due in mid-February will be delayed until March. This delay is due to a requested design change that replaces one large air stripping unit with two medium-sized units, as it was determined the larger one alone couldn’t handle the plant capacity.   

Dec. 28, 2016
After obtaining all necessary approvals from involved agencies, Water Treatment Plant #4 was taken out of service at 8:10 a.m. Wednesday, Dec. 28, 2016. It will remain out of service until upgrades to the plant, including air strippers, are completed - most likely summer 2018.

Dec. 19, 2016
At its Dec. 19, 2016, regular meeting, the St. Louis Park City Council supported staff's recommendation that Water Treatment Plant #4 be taken out of service as of Jan. 1, 2017. Below are some questions and answers about this action.

  • Why is the city taking Water Treatment Plant #4 out of service? 
    The decision to take Water Treatment Plant #4 (4701 41st St. W.) out of service, was made out of an abundance of caution and to preserve public trust in the quality of the city’s water. Even though it meets safe drinking water standards set by the US Environmental Protection Agency (EPA) to be in compliance with the Safe Drinking Water Act, aggressive, regular testing continues to suggest that the water quality at Water Treatment Plant #4 is not where the city would like it to be. 
  • When did concerns about Water Treatment Plant #4 start? 
    The city was advised in early 2016 of exceedances of health risk levels, set by the Minnesota Department of Health (MDH) and at much lower limits than those of the EPA, for some types of volatile organic compounds (VOCs) at Water Treatment Plant #4. 
  • Why didn’t the city take the plant out of service when the health advisory was received? 
    Before receiving the advisory, the city was already working with MDH to develop a short-term solution to lower VOC levels at Water Treatment Plant #4. This short-term solution has shown positive results for lowering certain VOC levels, including vinyl chloride, at Water Treatment Plant #4. However, recent testing revealed an increase in other VOCs such as trichloroethene (TCE); it’s those test results that prompted the decision to take Water Treatment Plant #4 out of service.
  • Will residents experience any negative effects from this action? 
    The city has sufficient water capacity to compensate for taking Water Treatment Plant #4 out of service. Plans were already in place to take this plant out of service for improvements; this simply moves up the timetable. Residents should not experience any negative impacts in water supply or pressure. In case of extreme emergency, St. Louis Park has relationships with all of its neighboring cities and can ask for assistance in supplying additional water. 
  • What’s the long-term plan for Water Treatment Plant #4? 
    The city is working with the MPCA on upgrades to this plant, including an air stripper. Upgrades will permanently address volatile organic compounds (VOC) levels, including those for which the increases prompted taking the plant out of service. Improvements are in the design phase and construction will begin in 2017.
  • Should residents be worried about water quality overall in the city? 
    Repeated testing by the Minnesota Department of Health has confirmed that the City of St. Louis Park water is safe to drink and meets all drinking water standards set by the US EPA to be in compliance with the Safe Drinking Water Act. While we were disappointed to discover an increase in certain volatile organic compounds (VOCs) at this particular plant, we consider it good news that our regular, aggressive testing of our water across the system is doing just what it’s supposed to – protect the public health and ensure continued delivery of safe, quality drinking water to residents.
  • Water Treatment Plant #4 has been taken out of service and is no longer supplying drinking water; however, is it still pumping water in relation to the Reilly Consent Decree? 
    Water Treatment Plant #4, supplied by drinking water well SLP4, was taken out of service entirely. Involved agencies supported transferring (adding) the Reilly Consent Decree/Remedial Action Plan pumping requirements for drinking water well SLP4 to drinking water wells SLP10 & SLP15 (both treated at Water Treatment Plant #1). These pumping requirements are in addition to Reilly-related pumping requirements already in place at drinking water wells SLP10 & SLP15 but still within the treatment capabilities of Water Treatment Plant #1.

November 2016
The city completed the system reconfiguration of Water Treatment Plant #4 (i.e. the short-term fix). Initial test results show the success rate of the short-term fix to range between a 22-58 percent reduction in vinyl chloride levels. The amount of reduction is dependent on the raw water levels and the contact time within the plant (which is driven by usage demand). The average VC level going into distribution is approximately 1.0 ug/L. The Minnesota Department of Health (MDH) has stated this is an acceptable reduction as it matches their goal of 50 percent of the MCL criteria of 2.0 ug/L.To increase confidence in the results, the city increased sampling frequency from monthly to every two weeks and asked MDH to increase their sampling frequency from quarterly to monthly.  

Funding for the permanent fix for Water Treatment Plant #4 was moved from the city's 2018 Capital Improvement Program (CIP) to 2017. The permanent fix includes upgrades to Water Treatment Plant #4 such that identified contaminants can be treated down to MDH’s published advisory levels (known as Health Based Values, HBVs, or Health Risk Limits, HRLs). 


October 2016
The Minnesota Department of Health released a drinking water report intended to provide and explain drinking water quality data in St. Louis Park. 

March 2016
The Minnesota Department of Health (MDH) notified the city that it was issuing a Notice of Health Risk Advisory for Water Treatment Plant #4 effluent. The advisory was based on exceedance of a health risk limit for vinyl chloride and exceedance of the Health-Based Based Value for cis-1,2-dichloroethene. As noted in the 2015 Drinking Water Report, none of these exceedances were MCL exceedances. MCL stands for Maximum Contaminant Level and is the highest level of a contaminant that is allowed in drinking water, enforceable by the MDH.  

Prior to receiving the MDH Health Risk Advisory, the city had been working on a solution, which was since approved by the US Environmental Protection Agency and the Minnesota Pollution Control Agency. 

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