Summary of Minnesota's Water Reuse Guideline or Regulation for Industry

This page is part of the EPA’s REUSExplorer tool, which summarizes the different state level regulations or guidelines for water reuse for a variety of sources and end-uses.
The source water for this summary is Treated Municipal Wastewater.

On this page:

• Technical basis
• Water reuse industrial applications approved for use in Minnesota
• Water reuse treatment category for industrial applications
• Additional context and definitions
• Water reuse for industrial applications specifications (table)
• Upcoming state law or policy
• References
• Disclaimer

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This page is a summary of the state’s water reuse law or policy and is provided for informational purposes only. Please always refer to the state for the most accurate and updated information. 

In Minnesota, water reused for industry water reuse for industryThe use of recycled water for industrial applications, often created at the industrial facility. This includes recycled water generated through onsite processes such as boiler water, cooling water, manufacturing water, and oil and gas production, as well as recycled water generated offsite and imported elsewhere for industrial reuse applications. includes reuse for certain cooling purposes, process water and boiler feed water. The source of water (treated municipal wastewater) treated municipal wastewaterTreated wastewater effluent discharged from a centralized wastewater treatment plant of any size. Other terms referring to this source of water include domestic wastewater, treated wastewater effluent, reclaimed water, and treated sewage. is specified by the state as municipal wastewater. The write-up on this page uses state terms when discussing sources or uses of water that may differ from the Regulations and End-Use Specifications Explorer's (REUSExplorer's) terms.

Technical basis

Minnesota approves the use of treated municipal wastewater for industrial applications including cooling or air conditioning where mists are both created and not created, as well as for use as industrial process water where contact with workers both is and is not expected (MPCA, 2010a). Minnesota also approves the use of industrial process water on a case-by-case basis. All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met in addition to any state water quality standards. In some reuse situations, such as industrial reuse, the industry may not have a separate National Pollutant Discharge Elimination Systems (Permits Program)/State Disposal System (Permit) discharge permit and will return the wastewater to the municipality. Although Minnesota allows this, the state recommends that additional concerns be addressed to ensure the returned water does not overload or upset the permitted facility’s treatment process (MPCA, 2010a). Minnesota states that “reuse activities are categorized based on public access and the risk for the potential for human exposure with the effluent” (MPCA, 2010a). Treatment requirements are based on the type of reuse and respective performance standards are based on detectable total coliforms in finished water for reuse applications. Minnesota uses California’s Title 22 Water Recycling Criteria (Cal. Code Regs. tit. 22) as the technical basis for the derivation of total coliform removals and turbidity requirements (defined in the table).

The basis for the state guidance is as follows: “Since 1992, the Minnesota Pollution Control Agency (MPCA) has used the State of California Regulations as guidance for the permitting of wastewater reuse” because California was one of the first states to develop detailed regulations to ensure that the reuse of wastewater would be protective of human health (MPCA, 2010a). “The required level and type of treatment is based on the type of reuse and establishes the total coliform bacteria that are allowed to be detected in the final treated water (MPCA, 2010a). Total coliform is used for the regulation of wastewater reuse rather than fecal coliform (MPCA, 2010a). A total coliform limit is more restrictive than a fecal coliform limit and is used as an additional safety measure (MPCA, 2010a).”

Water reuse industrial applications approved for use in Minnesota

The Minnesota Pollution Control Agency (MPCA, 2010a) defines the following approved industrial applications for treated municipal wastewater:

• Industrial process water that may come in contact with workers (Disinfected Tertiary)
• Industrial cooling or air conditioning involving cooling towers, evaporative condensers, or spray that creates mist (Disinfected Tertiary)
• Industrial process water that will not come into contact with workers (Disinfected Secondary 23)
• Industrial boiler feed water (Disinfected Secondary 23)
• Industrial cooling or air conditioning not involving cooling towers, evaporative condenser, or spray that creates mist (Disinfected Secondary 23)

Water reuse treatment category for industrial applications

The treatment requirements for municipal wastewater are briefly summarized for industrial applications:

• “Disinfected Tertiary”: Tertiary treatment with disinfection is required. Prior to disinfection, effluent must undergo secondary treatment and filtration. 
• “Disinfected Secondary 23”: Secondary treatment with disinfection is required. 

The reuse of wastewater generated from industrial process waters that do not contain human wastes are not subject to these requirements for industrial applications and are approved on a case-by-case basis.

Additional context and definitions

In Minnesota, municipal wastewater can be reused at industrial facilities, including ethanol or other biofuel facilities (MPCA, 2010b). In industrial facilities, the highest level of risk for human contact may occur when municipal wastewater is being utilized in a process, or cooling/air conditioning involving cooling towers, evaporative condensers, or spray that creates mist (MPCA, 2010b). Use for these industrial applications requires a higher level of treatment than reuse for boiler feed or cooling/air conditioning (MPCA, 2010b). 

Minnesota recommends that industrial facilities consider site-specific factors when considering whether treated municipal wastewater is a viable option for an industry (MPCA, 2010b). These include:

• The need for additional treatment (e.g., to address nutrient and salt levels and consideration of emerging contaminants)
• Impact on byproducts and co-products
• Infrastructure (e.g., How far away is the facility from the source water? Is additional infrastructure needed and at what cost?)
• Management of treatment residuals after reuse at the industry
• Quantity (e.g., How much treated wastewater is needed? Is storage needed?)
• Water supply alternatives (e.g., What are the other sources of water at the site?)

In areas where recycled water is used, signs must be posted that state that the water used is recycled, nonpotable and not fit for consumption (MPCA, 2010a). No physical connection is allowed between any recycled wastewater source and a potable water source. Hose bibs cannot be installed in areas accessible by the general public (MPCA, 2010a). Only quick connect couplers that differ from those used on the potable water system can be used on the recycled wastewater (MPCA, 2010a).

Water reuse for industrial applications specifications

Summary of Minnesota's Water Reuse for Industrial Applications Reuse Specifications

Source = MPCA (2010a)

^* Information about sampling and monitoring requirements such as frequency, site and quantification methods not specifically listed in the table was not explicitly specified in the state-specific regulations.

^a The use of industrial process water for industrial applications is approved on a case-by-case basis.

Upcoming state law or policy

No upcoming regulations related to water reuse for industry were found for Minnesota.

References:

Clean Water Act, 33 U.S.C. §§ 1251 et seq.

Minnesota Department of Health. 2018. Advancing Safe and Sustainable Water Reuse in Minnesota: 2018 Report of the Interagency Workgroup on Water Reuse.

Minnesota Pollution Control Agency (MPCA). 2010a. Municipal Wastewater Reuse.

Minnesota Pollution Control Agency (MPCA). 2010b. Biofuels: Reusing Municipal Wastewater.

Water Recycling Criteria, Cal. Code Regs. tit. 22.

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Disclaimers

Please contact us at [email protected] if the information on this page needs updating or if this state is updating or planning to update its laws and policies and we have not included that information on the news page.