Best Practice Action 20.4
GreenStep City Best Practices: Environmental Management
Efficient Water and Wastewater Systems No. 20
Assess and improve city drinking water and wastewater systems and related facilities.
Best Practice Action Detail
Best Practice Action 4
Optimize energy and chemical use at drinking water/wastewater facilities and decrease chloride in wastewater discharges.
Chloride:
- Much of Minnesota has hard water, which prompts people to use water softeners. Water softeners need salt (which contains chloride) to recharge their softening capacity, and the resulting salty brine is discharged to municipal wastewater treatment plants in most cities. The plants are not designed to remove chloride from wastewater, so the chloride ends up in the receiving water, usually a lake, river, or stream, where it has a permanent and irreversible impact on human health and environmental concerns.
- Short of expensive reverse osmosis or lime softening, there is no feasible way to remove salt from wastewater. Learn more about water permit holders and chloride reduction and Alternatives for addressing chloride in wastewater effluent (MPCA, 2018)
- See the Costs and benefits of household water softening: a review (UofMN, 2019)
- Consider central softening of drinking water like the City of Marshall.
- Encouraging residents to take steps (Living Green 365, 2017) to reduce home water softener salt use.
- Implement a rebate program to upgrade their water softeners.
Nitrates:
- The first in the State, the City of Cold Spring built a nitrate removal plant that uses bacteria to remove nitrates from drinking water, creating oxygen and nitrogen gas as by-products.
Facility resources:
- See U.S. EPA resources on efficient and more sustainable management of these public utilities.
- MnTAP (Minnesota Technical Assistance Program), a free assistance provider at the University of MN, will help develop recommendations that might be fundable using utility rebates.
- The Midwest Assistance Program focuses on communities under 2,500 in population (allowing them to bypass a full RFP contracting process), and the MN Rural Water Association provides services at no charge to community water and wastewater systems and rural water districts with populations under 10,000.
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Inform residents about the ecological benefits of reducing water softener salt use; shift operation times of large pumps or activities so as to secure a cheaper electric rate; purchase cheaper 'interruptible rate' electricity; install a peaking generator for load shaving/cost savings as well as backup power. Report ductile drinking water pipe under BPA 15.8. |
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Report savings from reduced fluoride levels; evaluate pump efficiency, repair or upgrade to efficient ones and report on anticipated cost savings; launch a rebate program for residents to optimize, upgrade or remove their water softeners. |
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Implement other/longer payback period drinking water facility upgrades such as measurable reduction in chemical use, use of backwash water; soften drinking water and work to eliminate home water softeners. |
Who's doing it
Apple Valley -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The city has completed an energy audit and backwash optimization improvements.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Charless Grawe (City staff) | CGrawe@ci.apple-valley.mn.us | 952-953-2508
Partners:
Brooklyn Center -
Date action report first entered:
Date of last report update:
Year action initially completed: 2016
Implementation details:
Our Treatment Plant is on a peak shaving/cost savings program through xcel energy since it opened in 2016
In 2016 we reduced our Fluoride levels from .9 ppm -1.5ppm with a target of 1.2 to the new lower standard of .4ppm- .9ppm with a target of .7ppm.
Our treatment plant reuses the backwash water, reclaiming of 90% of the water used during backwash
In 2016 we reduced our Fluoride levels from .9 ppm -1.5ppm with a target of 1.2 to the new lower standard of .4ppm- .9ppm with a target of .7ppm.
Our treatment plant reuses the backwash water, reclaiming of 90% of the water used during backwash
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Andrew Hogg (City staff) | ahogg@ci.brooklyn-center.mn.us | 763-569-3327
Partners:
Edina -
Date action report first entered:
Date of last report update:
Year action initially completed: 2017
Implementation details:
Chemical use was optimized in 2016-2017 to decrease the use of chlorine solely in the disinfection process of Edina's drinking water by transitioning from chlorine to chloramine in the disinfection process and treatment of municipal drinking water. Chloramination has been shown to be the most cost-effective approach to reduce regulated DBPs as advised by the EPA. Through chloramination, the overall energy demand and cost-effectiveness associated with drinking water treatment is and has been reduced in Edina.
Outcome measures/metrics/money saved:
Dropped associated energy usage by 30-40% (by less pumping being required) and is a more cost-effective treatment method.
Descriptive File:
Descriptive links:
For more information contact:
Grace Hancock (City Staff) | ghancock@edinamn.gov | (952)826-1621
Partners:
Inver Grove Heights -
Date action report first entered:
Date of last report update:
Year action initially completed: 2000
Implementation details:
The City of Inver Grove Heights utilizes Xcel Energy's peak control program for the booster station and three of the city's wells. When Xcel experiences a high energy demand, the City can power the wells with our generators to receive a reduced energy rate.
To increase pumping efficiency, the City upgraded the water treatment plant's lift station with the financial assistance through an Xcel rebate. Operating pumps at the booster stations and well house have received annual variable frequency drive upgrades over the last 15 - 20 years.
In 2015, the Department of Health reduced the required concentration of fluoride in drink water. The City of Inver Grove Heights responded by reducing the concentration of fluoride added at the water treatment facility from 1ppm to 0.7ppm, which reduced the City's expenses on water treatment chemicals.
To increase pumping efficiency, the City upgraded the water treatment plant's lift station with the financial assistance through an Xcel rebate. Operating pumps at the booster stations and well house have received annual variable frequency drive upgrades over the last 15 - 20 years.
In 2015, the Department of Health reduced the required concentration of fluoride in drink water. The City of Inver Grove Heights responded by reducing the concentration of fluoride added at the water treatment facility from 1ppm to 0.7ppm, which reduced the City's expenses on water treatment chemicals.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Ally Sutherland (City Staff) | asutherland@invergroveheights.org | 651-604-8511
Partners:
Isanti -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The City has upgraded their force main wastewater pumps to dual air release / air vac for better performance and efficiency.
The City utilized the allowed 10% of recycles backwash water in the water treatment plant operations.
By using the clarifiers in the wastewater treatment plant, the City has lowered the amount of Aluminum Sulfate by approximated 1/3.
The City has lowered the amount of hydrofluorosilicic acid used to fluoridate the city’s drinking water in response to the new fluoride level rule.
The City utilized the allowed 10% of recycles backwash water in the water treatment plant operations.
By using the clarifiers in the wastewater treatment plant, the City has lowered the amount of Aluminum Sulfate by approximated 1/3.
The City has lowered the amount of hydrofluorosilicic acid used to fluoridate the city’s drinking water in response to the new fluoride level rule.
Outcome measures/metrics/money saved:
Descriptive File: view file
Descriptive links:
For more information contact:
Sheila Sellman (City staff) | ssellman@cityofisanti.us | 763-444-5512
Partners:
Marshall -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
2019: The Minnesota Public Facilities Authority (PFA) announced $12 million in loan and grant funding for water infrastructure projects in Atkin, Dassel, Gibbon, Marshall. “These projects will increase access to clean water and protect the environment,” said Governor Tim Walz. “This represents a great investment in the health and wellbeing of our local communities.” “Water infrastructure continues to be a vital resource for Minnesota communities,” said DEED Commissioner Steve Grove. “These projects represent an investment in the future health and economic growth of Greater Minnesota.”
Outcome measures/metrics/money saved:
2019: Marshall, $7,000,000
This project consists of improvements to the drinking water treatment plant that will reduce discharge of chlorides to the environment. Funding for this project comes from a Point Source Implementation grant of $7 million. In addition $4,585,492 will come from local sources.
This project consists of improvements to the drinking water treatment plant that will reduce discharge of chlorides to the environment. Funding for this project comes from a Point Source Implementation grant of $7 million. In addition $4,585,492 will come from local sources.
Descriptive File:
Descriptive links:
For more information contact:
Mark Antony (City staff) | MarkA@marshallutilities.com | (507) 537-7005
Partners: City of Marshall, Marshall Municipal Utilities, Minnesota Public Facilities Authority
Richfield -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
We have back-up generators and are already part of the Xcel Energy’s peak shaving program. We recycle all water used for backwashing and from the filter presses. This water gets pumped back to the head of the plant for re-treatment.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Russ Lupkes (City staff) | rlupkes@richfieldmn.gov | 6128619175
Partners:
Robbinsdale -
Date action report first entered:
Date of last report update:
Year action initially completed: 2022
Implementation details:
Robbinsdale's Centralized Water Treatment Plant was constructed and came online in 2022. The Plant softens water and as a result the City has done extensive outreach to inform residents that they no longer need their water softeners, encouraging them to turn them off, uninstall them, or at least decrease their in-home softening levels.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links: https://www.robbinsdalemn.com/home/showpublisheddocument/13829/638102318106630000
For more information contact:
Kayla Kirtz (City Staff) | kkirtz@ci.robbinsdale.mn.us | 763-233-5654
Partners:
Sherburn -
Date action report first entered:
Date of last report update:
Year action initially completed: 2018
Implementation details:
In late 2016, the City started construction on water treatment facility that contains a reverse osmosis membrane treatment. This allows for softer water coming out of the plant and for citizens to reduce their water softner or remove all together. We have seen a reduction in the amount of chloride in our wastewater system.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Kym Christiansen (City staff) | kym.christiansen@cityofsherburn.com | 507-764-4491
Partners:
Burnsville -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
-The City of Burnsville pumps the majority of it's water at night, securing a cheaper electrical rate.
-The City has many natural gas pumps and motors, versus electric.
-Installed a peaking generator for load/shaving and cost savings in the 1990s.
The City evaluates pump efficiency in it's 10 Year Cycle Rehabilitation Plan. If a pump needs to be replaced, the city applies for rebates that usually make the most energy efficient pumps that most cost efficient.
-The City has many natural gas pumps and motors, versus electric.
-Installed a peaking generator for load/shaving and cost savings in the 1990s.
The City evaluates pump efficiency in it's 10 Year Cycle Rehabilitation Plan. If a pump needs to be replaced, the city applies for rebates that usually make the most energy efficient pumps that most cost efficient.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Sue Bast (City staff) | basts@ci.burnsville.mn.us | 952-895-4524
Partners:
Coon Rapids -
Date action report first entered:
Date of last report update:
Year action initially completed: 2016
Implementation details:
In 2016, the City reduced its Fluoride feed rate from .9-1.5 parts per million (PPM) to .5-.9 PPM to the City drinking water. The City saw an annual savings of roughly $10,000.00 in its first year.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Kory Jorgensen (City staff) | KJorgensen@coonrapidsmn.gov | 763-767-6576
Partners:
Golden Valley -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
A third party electrical company inspects the City’s water and wastewater pumps on a yearly basis to ensure all pumps are working to their maximum efficiencies. The City has installed a peak shaving generator in its pump house and has replaced two out of the four water reservoir pumps with newer, more efficient models. There are plans to replace the remaining two pumps by 2020.
Outcome measures/metrics/money saved:
The average daily flow for the three cities that make up the Joint Water Commission (Golden Valley, New Hope, and Crystal) is 4.75 MGD. Between June of 2016 and June of 2017, the average daily electric usage for the Golden Valley reservoir was 2,043 kWh per day.
Descriptive File:
Descriptive links:
For more information contact:
Joe Hansen (City staff) | jhansen@goldenvalleymn.gov | 763-593-8038
Partners:
Rogers -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
In the summer of 2011, the Ciy hosted a MnTAP intern who researched process optimization options at the City's WasteWater Treatment plant. Following the recommendations of the study, the city has replaced its sludge pnd aerators with NEMA super premium efficient motors. In March 2012, the City began implementing the second round of recommendations, which includes installing dissolved oxygen sensors and VFD drives on rotors to optimize dissolved oxygen processes. This project has been budgeted and is expected to be completed by June 2012.
The attached MnTAP Intern report lists process optimization options and associated payback periods.
The attached MnTAP Intern report lists process optimization options and associated payback periods.
Outcome measures/metrics/money saved:
Descriptive File: view file
Descriptive links:
For more information contact:
Mike Bauer (City staff) | mbauer@ci.rogers.mn.us | 763-428-0974
Partners: MnTAP, MN GreenCorps
Saint Peter -
Date action report first entered:
Date of last report update:
Year action initially completed: 2015
Implementation details:
Homeowners in Saint Peter have water softeners equipment which automatically track water quantity usage and water hardness and will self adjust without the homeowner having to do a thing.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Todd Prafke (City Staff) | barbaral@saintpetermn.gov | 507-934-0663
Partners:
Bloomington -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The WTP lighting was upgraded from high bay metal halide to LED high bay fixtures in the fall of 2015.
The metal halide lighting was never turned off due to the nature of the type of light. If the lights were powered off and we turned them on, it would take 5 minutes for the lights to become fully lit. Meaning we never shut these lights off due to how long the light took to power back on. This was a huge energy hog and most of the time no one was in the room. By changing over to the LED, not only were the lights lower in wattage, they were brighter, and we were able to turn the lights on with instant lighting. The lighting in these rooms today are normally off and have a motion sensor to turn back on when needed.
The metal halide lighting was never turned off due to the nature of the type of light. If the lights were powered off and we turned them on, it would take 5 minutes for the lights to become fully lit. Meaning we never shut these lights off due to how long the light took to power back on. This was a huge energy hog and most of the time no one was in the room. By changing over to the LED, not only were the lights lower in wattage, they were brighter, and we were able to turn the lights on with instant lighting. The lighting in these rooms today are normally off and have a motion sensor to turn back on when needed.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Steve Gurney (City staff) | sgurney@BloomingtonMN.gov | 952-563-4606
Partners:
Detroit Lakes -
Date action report first entered:
Date of last report update:
Year action initially completed: 2021
Implementation details:
We have a chloride reduction implementation plan.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Bridget Penton (City Staff) | bpenton@cityofdetroitlakes.com | 218-846-7133
Partners:
Gilbert -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The improved wastewater plant has many implementations to provide longer payback for drinking water and other water uses. The new plant will get Gilbert below the dreaded mercury limit, as well as remove excess phosphorus from the water. Aerobic digestion will be used to alleviate and reduce waste. The new facility will remove many unnecessary chemicals that would eventually inadvertently end up in Lake Superior.
Outcome measures/metrics/money saved:
The hopes for the future are that Gilbert will meet the soon to be enforced mercury limit. Many people in Gilbert do not understand why there is a mercury limit, much less why they need to comply to it. This new facility will take the burden off their hands. The technology does the work for the people of Gilbert. Phosphorus and mercury do not belong in the St.Louis river, nor in Lake Superior.
Descriptive File: view file
Descriptive links:
For more information contact:
Sam Lautigar (City staff) | samlautigar@gilbertmn.org | 218-748-2214
Partners:
Northfield -
Date action report first entered:
Date of last report update:
Year action initially completed: 2002
Implementation details:
Installed generators for peak savings for drinking water and wastewater. 2000 (WW), 2002 (Well 3 & 4)
All well pumps are rebuilt every 8 years. Not based on efficiency, just on use.
All well pumps are rebuilt every 8 years. Not based on efficiency, just on use.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Beth Kallestad (City staff) | beth.kallestad@ci.northfield.mn.us | 507-645-3074
Partners:
Pierz -
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
We partner with Rich Prairie Sewer and Water for our City Sewer and Water. They test and monitor water and chemicals regularly to make sure that they are providing clean and healthy drinking water. They also have a generator in case of power failure that allows them to continue to operate.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Kari Tyson (City staff) | karit@pierzmn.org | 320-468-6471
Partners: Rich Prairie Sewer and Water District
Saint Cloud -
Date action report first entered:
Date of last report update:
Year action initially completed: 2001
Implementation details:
Energy and chemical efficiency evaluations are completed daily at both the drinking water and wastewater treatment facility. These evaluations are used to make changes to the treatment process to be as cost-effective and energy efficient as possible.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Tracy Hodel (City staff) | tracy.hodel@ci.stcloud.mn.us | 3202557226
Partners:
Savage -
Date action report first entered:
Date of last report update:
Year action initially completed: 2008
Implementation details:
The City uses SCADA (Supervisory Control and Data Acquisition) control panels system monitoring. The computer-based SCADA equipment provides information that makes it possible for utility personnel to more effectively monitor and maintain the sanitary (lift stations) and water distribution systems.
Water Treatment Plant Efficiency
The City of Savage standard operating procedure is to use state of the art equipment that is programmable logic controlled, scaled linearly to flow, and calibrated to an individual wells chemical makeup characteristics. This has resulted in immediate savings and chemical reduction to the City.
Water Treatment Plant Efficiency
The City of Savage standard operating procedure is to use state of the art equipment that is programmable logic controlled, scaled linearly to flow, and calibrated to an individual wells chemical makeup characteristics. This has resulted in immediate savings and chemical reduction to the City.
Outcome measures/metrics/money saved:
Descriptive File:
Descriptive links:
For more information contact:
Michael Klimers (City Staff) | mklimers@cityofsavage.com | 952-224-3442
Partners:
Greenstep Advisor
Gabrielle Martin, Assoc. Engineer, Minnesota Technical Assistance Program: 980.329.2647, gamartin@umn.edu, http://www.mntap.umn.edu/us/staff/gm/