Best Practice Action Detail

Best Practice Action 20.6

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 6

Implement a wastewater plant efficiency project (co-generation, water reuse) or a program for local private business operations (water conservation, water reuse, business co-location).

  • For free technical consultation contact MnTAP, at the University of MN. For financing options contact Bill Dunn at the MPCA, who can explain, among other funding, the Green Project Reserve funding from the MPCA for projects that reduce the environmental footprint of water and wastewater treatment, collection, and distribution, that help utilities adapt to climate change, enhance water and energy conservation, adopt more sustainable solutions to wet weather flows, and promote innovative approaches to water management problems.
  • See a Wastewater Reuse Policy Task Force report (Metropolitan Council: 2017) and Municipal Wastewater Reuse (MPCA: 2010).
  • Guidelines for Water Reuse (US EPA: 2012) covers water reclamation and reuse, planning for future water reuse systems, and information on indirect potable reuse and industrial reuse. Disinfection and treatment technologies, emerging contaminants, and public involvement and acceptance are also discussed.
  • In 2014 Elk River, for example, required businesses to take steps to keep grease out of sewer lines.
  • During 2011 the city of Brainerd investigated the possibility of using the city waste water system for heating and cooling purposes.
  • See Characterization of CHP Opportunities at U.S. Wastewater Treatment Plants (U.S. DOE: 2019) to learn about combined heat and power systems fueled by biogas from anaerobic digestion at WWTPs. As of October 2012, 62 publicly owned treatment plants in MN had anerobic digestion in place. For small-medium WWTPs in MN, the simple payback for installing CHP is 4-10 years.
  • See, for example, a 2012 industrial biogas project at Liberty Paper in which the City of Becker is a partner. A pretreatment facility at the Liberty paper mill will allow water to be pretreated on-site and methane captured and burned for in-plant energy use before the water is routed to the city's wastewater treatment plant.
1 star Assist local businesses and institutions with water conservation measures; assist businesses in pre-treating and lowering volumes and toxicity of sewer inflows.
2 star Reuse water (sell reclaimed water) from a wastewater plant for nonpotable ag-processing, irrigation, cooling or power plant uses; require businesses to take steps to keep grease out of sewer lines.
3 star Co-generate electricity and heat through anaerobic digestion at the wastewater treatment plant; comp plan/zoning that guides businesses using high volumes of non-potable water to within 2-5 miles of a waste water treatment plant.

Who's doing it

Albert Lea - 3 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
At the 6.7 MGD Waste Water Treatment facility, Albert Lea has operated a 120 kW on-site methane fired electric generation system since 2003.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Jerry Gabrielatos (City staff) | jgabrielatos@ci.albertlea.mn.us | 507-377-4316
Partners:
Austin - 3 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
WWTP has been using biogas from the industrial digeters to recover heat for heating of return sludge for many years.
Hormel Foods Corporate Office is using greywater in restrooms in the office expansion that was completed in February. -Methane gas is generated through the digesters and then is captured and is used as the fuel source for the boilers. The boilers heat the waste flow to optimize the biological process. The City operates two treatment plants and this process is used for both. At certain times the organic loading is not sufficient to produce enough biogas for the operation of the domestic plant and if possible we will divert flow from the industrial plant to try and supplement the loading thus increasing our gas production. This process provides for significant reductions in our needs for natural gas.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Janet Anderson (Community volunteer) | janetanderson2840@gmail.com | 5072190680
Partners: WWTP, Hormel Foods
Rochester - 3 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
Rochester has 2 main co-generator plants that supply a majority of the city. Franklin Heating Station, primarily serves Mayo Clinic, while Rochester Public Utilities is a more comprehensive supplier for the city.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Tony Benson (City staff) | tbenson@rpu.org | 507-280-1534
Partners:
Saint Cloud - 3 star
Date action report first entered:
Date of last report update:
Year action initially completed: 2014
Implementation details:
The Energy Efficiency and Biofuel Recovery Project started construction in June 2016 and is at substantial completion.The project consisted of installation of energy efficient and biofuel recovery equipment.
Outcome measures/metrics/money saved:
The facility can generate on average 80% of its electrical demand onsite through solar or biofuel. There are days when the facility produces more energy than it needs.
Descriptive File:
For more information contact:
Tracy Hodel (City staff) | tracy.hodel@ci.stcloud.mn.us | 3202557226
Partners: Xcel Energy, Apex Efficiency Solutions Inc
Shakopee - 3 star
Date action report first entered:
Date of last report update:
Year action initially completed: 2016
Implementation details:
In 2016, the City of Shakopee, the Metropolitan Council, and CenterPoint Energy developed the Blue Lake Solar Center, a solar farm with a Standard Test Condition of 325 W and a total DC system rating of 1.638 MW, to supplement the energy requirements of the Blue Lake Wastewater Treatment Plant, which treats an average of 27-29 million gallons of wastewater per day. The system will provide approximately 10% of the annual power usage by producing approximately 1,720,000 kWh per year replacing the equivalent of 1.3 million pounds of coal. According to project reporting, the treatment facility and solar farm will offset the use of 1.25 MW and 1.0 MW of fossil fuel and additional power generation infrastructure as well as producing 2,195 MWh in year 1 of clean, renewable energy to the WWTP in Shakopee. The generation of biogas is estimated to offset an average of 1,690 metric tons of carbon dioxide emissions each year, the equivalent to removing 255 passenger vehicles from the road a year or 3 million miles driven by a single automobile. The Metropolitan Council projected and documented energy savings of 80,000 Dth/year is about 80% of the dryer’s pre-project energy consumption and reduces the mass of the solids loading to be dried by 30%. Additionally, the 1,720,000 kWh of solar energy is estimated to replace the release of over 56 pounds of N20 and 90 pounds of Methane. The total amount of energy produced by the 1.25 MW Facility will eliminate an estimated 2,100 metric tons of carbon dioxide, 70 pounds of N20 and 113 pounds of Methane.

The use of the anaerobic digestor produced energy savings equivalent to the annual gas usage of 900 residential customers per year and reduced consumption of purchased natural gas by 80%. The heat recovery system installed on the dryer scrubber system which allows the system to recover 1.85 MMBtu/hr of waste hot water from an odor control system to maintain the digester’s operating temperature of 98 F, eliminating all heating requirements of the digesters whenever the dryer is operating. The biogas will be used to fuel boilers for heating the control building.

Solids removed from the wastewater are dewatered, dried and pelletized for use as an agriculture fertilizer, under a public-private partnership between MCES and the New England Fertilizer Company (NEFCO) and an additional treatment process, anaerobic digestion, produces methane gas that helps power the solids drying equipment. The existing dryer burner equipment was retrofitted to burn either natural gas or the in-house produced biogas with 55-60% of the heat content of natural gas.

Other improvements made at Blue Lake include premium efficiency pump motors, motor drives, and the replacement of air diffusers and additional valves have provided better control over dissolved oxygen and improved oxygen transfer.

The Metropolitan Council projected and documented energy savings of 80,000 Dth/year is about 80% of the dryer’s pre-project energy consumption and reduces the mass of the solids loading to be dried by 30%.
Outcome measures/metrics/money saved:
The system will provide approximately 10% of the annual power usage by producing approximately 1,720,000 kWh per year replacing the equivalent of 1.3 million pounds of coal. According to project reporting, the treatment facility and solar farm will offset the use of 1.25 MW and 1.0 MW of fossil fuel and additional power generation infrastructure as well as producing 2,195 MWh in year 1 of clean, renewable energy to the WWTP in Shakopee. The generation of biogas is estimated to offset an average of 1,690 metric tons of carbon dioxide emissions each year, the equivalent to removing 255 passenger vehicles from the road a year or 3 million miles driven by a single automobile. The Metropolitan Council projected and documented energy savings of 80,000 Dth/year is about 80% of the dryer’s pre-project energy consumption and reduces the mass of the solids loading to be dried by 30%. Additionally, the 1,720,000 kWh of solar energy is estimated to replace the release of over 56 pounds of N20 and 90 pounds of Methane. The total amount of energy produced by the 1.25 MW Facility will eliminate an estimated 2,100 metric tons of carbon dioxide, 70 pounds of N20 and 113 pounds of Methane.

The use of the anaerobic digestor produced energy savings equivalent to the annual gas usage of 900 residential customers per year and reduced consumption of purchased natural gas by 80%. The heat recovery system installed on the dryer scrubber system which allows the system to recover 1.85 MMBtu/hr of waste hot water from an odor control system to maintain the digester’s operating temperature of 98 F, eliminating all heating requirements of the digesters whenever the dryer is operating.

The energy savings from generating 10% of the WWTP's annual energy needs will be passed on to approximately 300,000 residents and businesses that pay the cost of wastewater treatment throughout the metro area.
Descriptive File: view file
For more information contact:
Andrew Boucher (City Staff) | aboucher@shakopeemn.gov | 952-233-9347
Partners: Metropolitan Council, Xcel Energy, CenterPoint Energy
Detroit Lakes - 2 star
Date action report first entered:
Date of last report update:
Year action initially completed: 2020
Implementation details:
The City of Detroit Lakes is currently constructing a new $35M wastewater treatment plant. This sizable investment for a community of our size will enable us to produce high quality discharge water to preserve water quality in a vast region of Western Minnesota. Our facility will help preserve water quality, excellent recreational activities, and protect downstream watersheds for years to come.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Vernell Roberts (City Staff) | vroberts@cityofdetroitlakes.com | 2188475658
Partners:
Mankato - 2 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
Upgrades the city has been making to Mankato's water treatment plant are designed to conserve energy and minimize costs by drawing more water from surface wells that have high-capacity output with low maintenance.

The city's water reclamation facility continues to provide advanced wastewater treatment, similar to a drinking water plant.

Organic byproducts of the wastewater treatment process are made available to area farmers for use as fertilizer. The City maintains certification with the National Biosolids Partnership for effective and efficient handling of biosolids in this land application program.

A new station was built in 2011 that includes a fill station where trucks can fill their tanks with City reclaimed water from the wastewater treatment lant. City employees use this water for street sweeping, sod establishment, and pipe testing, and the City is also planning to sell this water to those who have purchased drinking water in the past for such purposes.
Outcome measures/metrics/money saved:
Mankato's surface water well has reduced the city's use of water from deep wells (tapping the Mount Simon aquifer) by about 50 percent.

Between 1.5 and 2 million gallons of treated wastewater is being used by the Mankato Energy Center for cooling, which saves the city nearly 700 million gallons of water annually and has significantly reduced phosphorous levels.

The City used 1.2 million gallons of reclaimed Title 22 water in 2011 to irrigate the new Riverfront Park.


Descriptive File:
For more information contact:
Molly Westman (City staff) | mwestman@mankatomn.gov | 507-387-8571
Partners:
Red Wing - 2 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
A) Industrial pretreatment program that engages business to lower toxicity or volume of waste discharges to POTW.
D) One grey water reuse system in the city
Outcome measures/metrics/money saved:
Record the business that get involved in the toxicity or reduction actions and also list the gret water re-use site(s)
Descriptive File:
For more information contact:
Steve Stadler (City staff) | sstadler@hopkinsmn.com | 952-548-6350
Partners:
Saint Anthony - 2 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The City of St. Anthony reuses backwash water from the water treatment plant to replace potable water used for irrigation in a +20 acre park and City Hall site.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Jay Hartman (City staff) | jay.hartman@ci.saint-anthony.mn.us | 612-782-3314
Partners:
Two Harbors - 2 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The city has always used plant effluent water for wash downs in place of city water whenever possible in order to conserve water supplies.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Sven Bergerson (City staff) | berger55@frontiernet.net | 218-834-8814
Partners:
Bemidji - 1 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
A grease waste reduction project commenced in September 2013 to reduce the amounts of fats, oils and greases entering the Wastewater Treatment facility by 10%. Baseline measurements of FOG were taken and compared with years prior and a collaborative education initiative is underway to educate restaurants and commercial kitchen operators about best management practices for FOG waste. The first of many conversations about this topic occurred on April 23rd at a public presentation entitled, "Grease Waste in Bemidji: Cleaning Up the Headwaters."
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Al Gorick (City staff) | al.gorick@ci.bemidji.mn.us | 218-333-1865
Partners:
Crosslake - 1 star
Date action report first entered:
Date of last report update:
Year action initially completed: 2017
Implementation details:
City of Crosslake Wastewater Treatment Project
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Martha Steele (Community volunteer) | steeles@brainerd.net | 218-765-4041
Partners:
Hoffman - 1 star
Date action report first entered:
Date of last report update:
Year action initially completed: 2018
Implementation details:
City Maintenance is working at cleaning up the sewer ponds with the help of the MPCA. Bugs have been placed in the ponds to help with algae and sludge.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Dianne Johnson (City staff) | heda@runestone.net | 320-986-2448
Partners: Minnesota Pollution Control, Department of Health
Hutchinson - 1 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
All water used in treatment processes at Hutchinson’s Wastewater Treatment Facility is recycled effluent from the treatment process.
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
John Paulson (City staff) | jpaulson@ci.hutchinson.mn.us | 320-234-5682
Partners:
Saint Paul - 1 star
Date action report first entered:
Date of last report update:
Year action initially completed:
Implementation details:
The City's Comprehensive Plan Water Chapter has policies on gray water, rain barrels, drip irrigation, and “lost water”. (pp. W9-W10)
Outcome measures/metrics/money saved:
Descriptive File:
For more information contact:
Kurt Schultz (City staff) | kurt.schultz@ci.stpaul.mn.us | 651-266-6590
Partners: