Biosolids

Biosolids from St. Cloud being transferred to a field applicator. The MPCA encourages the beneficial reuse of biosolids in a manner that protects human health and the environment. Biosolids are generated in the treatment of domestic wastewater. The treatment of these solids produces a nutrient-rich organic material that can be used by farmers. Various wastewater treatment processes stabilize and disinfect the solids, destroying harmful bacteria and reducing odors. The result is a humus-like organic matter, dry powder, pellets, slurry, or liquid that bear little resemblance to the untreated solids from which they were derived. Biosolid recycling reduces both the amount of waste going to landfills and incinerators and the total use of petroleum-based chemical fertilizers.

Biosolids that will be applied to land, individuals overseeing land application, and land application sites all must meet strict regulations and quality standards. State and federal rules govern the use and disposal of biosolids, set limits for contaminants such as metals, and require pathogen and vector attraction reduction, site and crop harvesting restrictions, and record keeping and reporting.

Biosolids coverage in NPDES permits

These entities must seek biosolids coverage in their NPDES permits:

  • Municipalities with mechanical treatment
  • Large subsurface treatment systems that are publically owned
  • A large subsurface treatment system that has a mechanical component like denitrification

Domestic wastewater facilities that clean out their ponds or decommission ponds must follow the Decommissioning or Relining Domestic Wastewater Ponds: Requirements and Procedures.

If your facility produces biosolids, complete the Microsoft Office document icon Municipal Biosolids Attachment (wq-wwprm7-16) in addition to the appropriate application.

Staying in compliance

Forms and reporting requirements you'll need to maintain compliance with biosolids regulations.

Site application forms (submit prior to using site)

State biosolids annual report (due Dec. 31 each year)

  • State reports cover Sept. 1 to Aug. 31 cropping year
  • Must be submitted even if no solids were applied during this period.
  • Microsoft Office document icon Biosolids Annual Report

EPA annual reports (due by Feb. 19 each year)

Any facility described below must submit reports:

  • Class 1 management facilities (EPA Title 40, Chapter I, Subchapter O, Part 501.2) 
  • Facilities with a design flow rate of greater than 1,000,000 gallons per day
  • Publicly owned treatment works that serve a population of 10,000 people or more

EPA will accept Minnesota permittee’s information on a cropping year. Change the calendar at the beginning of the form to reflect this. Change your dry tons to metric dry tons. Submit both the state report and the EPA report.

Compliance and annual reporting guidance about Clean Water Act laws

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