Quality and Safety

Following the vision, values, and ethics of the Metropolitan Council, the Empire Wastewater Treatment Plant strives to be a long-term steward and valued leader in water sustainability. The facility rigorously tests the physical, chemical, and microbial properties of its biosolids to ensure that the finished product continually meets regulatory specifications and remains high quality.

The Empire Plant’s Farmers First land application team works side by side with local farmers and the community to follow best management practices set by the Environmental Protection Agency (EPA) and the Minnesota Pollution Control Agency (MPCA) for biosolids land application. Implementing these measures improves pollution prevention efforts, which ultimately increases public safety as well as protection of the environment.

Standards and regulations

To ensure the highest land application quality and safety, both the EPA and the MPCA have set standards and regulations for producing and managing biosolids. The current mandates were originally enacted in 1972 by the Clean Water Act to protect U.S. waterways. This law safeguards the nation’s valuable wetlands, streams, and other waterbodies against reckless development and pollution discharges. Under its provisions, the EPA has established guidance and best management practices for the wastewater industry that include the use and disposal of treated sewage sludge, also known as “biosolids” (40 CFR Part 503, 1993).

Part 503 focuses on three specific parameters for determining the quality of biosolids:

1. The presence of pollutants (arsenic, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc)
2. The presence of pathogens (e.g., bacteria, viruses, parasites)
3. The biosolids’ attractiveness of vectors (e.g., rodents, flies, mosquitoes)

The EPA and MPCA have defined several quality specification limits for each of the criterion listed above. From these quality standards, the treated biosolids produced by the Empire Wastewater Treatment Plant for its Farmers First program has been classified as a Class-B fertilizer that can be used for agricultural land application.

Along with quality, the governing agencies have also established best management practices to help ensure that biosolids are applied in a safe and effective manner. Areas of guidance include:

• Removing threats to endangered species and their habitat
• Controlling application to flooded or snow-covered land to mitigate leaching
• Keeping safe distances away from water resources to avoid nutrient contamination
• Following agronomic rates (application rates) to eliminate nitrate leaching and runoff