City Council Meeting Date: February 11, 2025
To: Mayor and City Council
City Administrator
From: David Bennett, P.E., Public Works Director/City Engineer
Justin Wagner, Utilities Manager
Title
Discussion on the Water Treatment Plant.
Body
Action Requested:
The Northfield City Council discusses the water treatment plant.
Summary Report:
Project Summary Background
On January 21, 2025, the City Council rejected bids for the water treatment plant. Tonight, staff are bringing back the topic to present options for the City Council related to the water treatment plant. Ideally, staff would receive policy direction from the City Council about how the City wants to move forward on the project using one of the options. Or, alternatively, seek policy direction on other information or options to explore.
The City has levels of manganese above health-based guidance for infants under 1 year old that can cause learning and behavior issues. More specifically, three of five wells have been over the limit on a consistent basis. Our most recent sample has 3 of 5 wells over and a 4th well at 96.5ug/L. For reference, well 2 - 70.7 ug/L, well 3 - 140 ug/L, well 4 - 131 ug/L, well 5 - 96.5 ug/L and well 6 - 115 ug/L. If residents have infants under 1 year old, they should further treat their tap water prior to giving it to infants. The following are specific recommendations on how homeowners can remove manganese now in their drinking water at home:
Ways homeowners can remove manganese in their drinking water at home
o Use of a carbon filter rated to remove manganese at 150 ug/L to levels below 100 ug/L;
o Use of distilled water or a distillation system;
o A water filtration system rated to remove manganese at 150 ug/L to levels below 100 ug/L;
o A reverse osmosis water system or under the sink reserve osmosis system;
o Use of a water softener that is connected to your drinking water faucet.
Note: Most water softeners are not set up this way due to taste of softened water and would require different plumbing. Likely, even if a resident has a water softener they likely will have to replumb the water lines to any facets that would be desired to use for consumption of water for infants under 1 years old.
Due to the level of manganese in the water, the City Council approved a contract with Bolton and Menk to study the water system and provide ways to lower the level of manganese in the water. Bolton & Menk is recognized for their extensive expertise in designing and engineering safe and reliable public drinking water systems, including water treatment plants, storage facilities, and distribution networks, ensuring they meet community capacity needs and comply with relevant regulations; they are considered a leading firm in the field of water treatment engineering with a large staff dedicated to water and wastewater treatment solutions. They were selected through a vetted solicitation process and represent the interests of those communities they serve including the City of Northfield.
A project of this scale and complexity follows a multi-step, vetted process that evolves over time, becoming increasingly refined in detail. As part of the water system study that was accepted by the City Council on April 5, 2022, a water treatment plant that consisted of gravity filtration with reverse osmosis was recommended. The City Council then authorized the request for proposals for design of the water treatment plant and approved Bolton and Menk on April 18, 2023, to design the water treatment plant. On November 12, 2024 the City Council approved the plans and specifications and authorized advertisement for bids. Staff then brought a recommendation forward of the water treatment plant that was rejected on January 21, 2025. Based on the rejected bids, staff are bringing back four (4) potential options for moving forward.
Federal Funding
Staff are looking into federal funding to get additional timeline requirements since the City may be looking for an alternative use of the federal funds. The federal funding was identified originally in the federal bill for $3.945 million to be used for the City of Northfield for water/wastewater projects. The Army Corps of Engineers (ACOE) is required to bid the project and the City will reimburse the ACOE for its 25% cost share. Additionally, the City and the ACOE need to be in an agreement during the summer of 2025. The funding was identified to be used for the water treatment plant and specifically for the purchase of the reverse osmosis skids at the water treatment plant. With the reverse osmosis portion of the water treatment plant in question, a new source for the funding is needed. Staff have identified the NW Area water tower as an option for the funding. With the most recent water rates update, the water tower was recommended to be moved to 2030 to help minimize rate increases. If the water tower was identified for the use of the funding, an estimated additional $4.453 million will be needed in City funding that will not go through the Public Facilities Authority (PFA). Rates would be increased by an estimated $2.23 per month for the water tower project. Staff is still working through details with the ACOE on this issue and would have more information in the future.
Staff would welcome input on this issue. Unless otherwise articulated, our presumption would be support for this option as it is planned in the Capital Improvement Plan (CIP), reduce costs to the water fund regardless of the water plant, and provide added value to the existing business (including Northfield Hospital & Clinics, housing areas) and will increase capacity for additional prospective industrial development in the Northwest area.
Water Treatment Plant Options
Items to consider for all four (4) options (based on cost estimating at this time):
- Staff will work with the contractor and engineer to value engineer during the construction project. The contractor has brought forward roughly $500,000 in potential savings to start the project. There would be an opportunity to also explore some participation of Council or other stakeholders from the community if that would be of interest to provide more ownership and understanding. This would be further explored if of interest.
- Water rates are increasing an estimated $10 per month by 2030 for non-Water Treatment Plant Capital Projects.
- It is estimated that for every $2,000,000 in project savings, there is a $1.00 per month decrease in monthly water rates.
- Project costs per sq. ft. is approximately $405 for Reverse Osmosis, $490 for office area and $385 for garage space.
- Redesigning the facility will take between 6 and 12 months and cost between $200,000 and $900,000 in design services.
- Project costs are increasing 0.4% to 1.0% per month.
- No formal water rate study was conducted based on the updated numbers but using the previous model for general rules.
- Current interest rates are stable; however, future interest rates are unknown.
- All the rates are based on the average water user.
The four (4) options in summary are as follows:
1. Construct a water treatment plant using gravity filtration and have the staff garage area sized for current use for moving staff to the water treatment plant as recommended in the water system study.
2. Construct a water treatment plant using gravity filtration and only construct a garage and office space to house staff specifically working at the water treatment plant. The remainder of Utilities staff would continue to office at the current utilities department at 1101 College Street.
3. Not construct a water treatment plant currently but construct the raw watermains, trunk sewer line and roadways.
4. Rescind the resolution rejecting bids and awarding the bid project to Magney Construction.
The four (4) options in greater detail are as follows:
Option 1: Construct a water treatment plant using gravity filtration and have the staff garage area sized for current use for moving staff to the water treatment plant as recommended in the water system study.
Construction of a water treatment plant using gravity filtration will be used for treatment of manganese. Option 1 would remove reverse osmosis from the treatment plant. A portion of the garage would be removed and would be constructed for today’s use instead of future use. The meeting room and part of the entryway would be removed, and the training room and exercise rooms would be combined into a meeting room. This would remove approximately 14,025 sq. ft. All utilities staff and equipment would move to the water treatment plant as recommended in the water system study.
Option 1 is estimated to cost between $58.10 and $60.47 million for the water treatment plant. There would be an additional $1.67 million savings from not purchasing the reverse osmosis skids through the ACOE. The total project savings vs. the bid project are estimated to be $3.04 to $5.41 million. Rate savings would be estimated to be between $1.52 to $2.71 per month. The rate savings would be reduced by using the federal funds for the water tower.
Option 2: Construct a water treatment plant using gravity filtration and only construct a garage and office space to house staff specifically working at the water treatment plant. The remainder of Utilities staff would continue to office at the current utilities department at 1101 College Street.
Construction of a water treatment plant using gravity filtration will be used for treatment of manganese. Option 2 would remove reverse osmosis from the treatment plant. All of the garage, except the JetVac stall, as well as a small garage area for work/staff vehicles, would be included. The staff office area would be removed except for a small area for 2-3 staff working at the water treatment plant and critical operation areas of the facility (office, laboratory, SCADA, restroom and breakroom). The building would be reduced by approximately 28,815 sq. ft. Utilities staff and equipment would stay at the current locations except the JetVac would be moved to the water treatment plant. The garage and office space would be planned for a future capital project.
Option 2 would be estimated to cost between $52.50 and $55.24 million for the water treatment plant. That would be an additional $1.67 million savings from not purchasing the reverse osmosis skids through the ACOE. The total project savings vs. the bid project are estimated to be $8.27 to $11.01 million. Rates savings would be estimated to be between $4.14 to $5.51 per month. The rate savings would be reduced by using the federal funds for the water tower.
Option 3: Not construct a water treatment plant currently but construct the raw watermains, trunk sewer line and roadways.
Option 3 would be not to construct a water treatment plant at this point. Construction of the roadways, raw watermains and trunk sewer line would still take place at an estimated $9.18 million. Future costs of a water treatment plant based on the options above and the bid project are estimated in the table below at 1, 2, 3 and 5 years. The federal funds would be used for the water tower. The estimated rates in 2030 for Option 3 would be $37.09.
Note: Staff does not recommend this option since the City would still be providing elevated levels of manganese to residents including infants that cause learning and behavior issues from the level of manganese in our water. Pictures of the raw water, fire hydrants and water that has been sitting in a fire trunk are included for reference to the amount of iron and manganese in the water. However, if Council recognizes these issues and is comfortable with this standard to continue as we are now this would be an option.
Option 4: Rescind the resolution rejecting bids and awarding the bid project to Magney Construction.
Option 4 (original bid) would be to rescind the previous motion to reject the bids for the water treatment plant and award the project to Magney Construction. Magney Construction has indicated that they will extend their acceptance period by 30 days to a total of 90 days from the bid date of December 19, 2024. Or, alternatively there could be an agenda item on February 17th special meeting that would be within the original bid acceptance period. The City Attorney is currently reviewing the facts of this case and this option. The water treatment plant would cost $61.84 million, and the estimated rate would be $69.24 per month in 2030.
Financial Summary of Options:
- Lowest Cost to Residents and Businesses (year 2030)
o Option 3 - The average resident bill $56.09
§ The cost to build new in 2030 or beyond would be substantially more expensive estimated in the table below.
§ Includes estimated household self-funded costs for water softening of $19/month
o Option 4 - Average resident water bill $69.24
§ This is the current bid project
o Option 2 - Average resident water bill $82.73-$84.10
§ Remove softening and residents home soften water, utility staff relocates to new site
§ Includes estimated household self funded costs for water softening of $19/month
o Option 1 - Average resident water bill $85.53 - $86.72
§ Remove softening and residents home soften water, utility staff doesn’t relocate to new site
§ Includes estimated household self funded costs for water softening of $19/month
Staff are looking for direction from the City Council on how to move forward with treatment of manganese in our water based on the information provided.
Additionally, questions were asked of staff regarding use of a steel style (pole shed) building for the garage. Staff does not recommend construction of a steel style building for the garage due to the equipment to be stored in the facility is for emergency response such as the 2018 tornado, floods, emergency backups, watermain breaks, etc.
Link to water system study webpage: <https://www.northfieldmn.gov/1498/Water-System-Study>
Link to water treatment plant new construction project webpage: <https://www.northfieldmn.gov/1593/Water-Treatment-Plant-New-Construction-P>
Link to MDH - Manganese is Drinking Water: <https://www.health.state.mn.us/communities/environment/water/docs/contaminants/mangnsefctsht.pdf>
Alternative Options:
• The options are identified above.
• There had been previous suggestion of independent review of the plant design. As previously noted in the memo, Bolton & Menk are recognized experts in public drinking water systems and were selected through a professional and thorough proposal review process. Given their expertise and qualifications, staff does not believe an additional review by another firm specializing in public drinking water systems would provide meaningful value and would instead represent a redundant and unnecessary expense.
However, if credible information from qualified experts in public drinking water systems is presented that justifies the need for an additional review, staff is open to considering it. Absent such evidence, this issue has been set aside, as staff does not see a valid reason or purpose for pursuing further review at this time.
Financial Impacts:
Finances for each option are listed in the table based on options above.
Future Potential State and Federal Grants
Staff has not included any estimates of potential new Federal or State grants. We have been advised that it is possible but not necessarily something likely on any of the options for a new plant. Under current conditions, a similar award would be most likely a possibility on the higher end but definitely not in a $10 million range or higher. At the State level, we would likely get support from our representatives to get a bill for funding for a specific earmark in a bonding bill. However, much less likely than not that there would be any funding due to other programs for drinking water systems that are funded through a competitive and pointed system. Northfield is not likely to reach a threshold of those programs to be eligible for grants based on the formula.
Technology Advancements for Manganese and Iron
Gravity filtration has been a well-established treatment for manganese and iron for decades. There are not any advances in technology projected at this time known. However, if credible information from qualified experts in public drinking water systems is presented that provides evidence that there is some emerging technology, staff welcomes the opportunity to review that information.
Tentative Timelines:
Staff will bring back a motion to the City Council for direction based on tonight’s discussion on either February 18 or March 4 depending on the direction of the City Council.