Biological Treatment & Phosphorus Trading

A combination of mechnical upgrades and water quality trading provided an effective solution to the land application difficulties associated with applying process wastewater


Originally owned and operated by a smaller farmers co-op, Hillside Dairy in Stanley, WI, has been producing award-winning cheeses since the early 1900’s. In 1960, the dairy was purchased by the LaGrander family and it became LaGrander’s Hillside Dairy, Inc. Nearly six decades later, the cheese plant is still family owned and operated, producing more than 60,000 pounds of cheese per day. The dairy produces cheese curds for Culver’s restaurants as well as dozens of other cheese varieties including string cheese, cheese spreads, cheddar and colby cheeses, as well as American, Parmesan, Muenster. Producing a significant amount of wastewater, LaGranders had historically been able to manage their wastewater through land application. Land application is severely limited during wet and winter conditions to reduce or eliminate any runoff potential. In recent years, it had become increasingly difficult to land apply, especially during restricted wet/frozen conditions. Faced with difficulties with land application, strict surface water discharge requirements, and the potential for future production expansion, the dairy looked to The Probst Group for a solution to meet their wastewater needs.


  • Remove dependency on land application
  • Allow for surface discharge while meeting stringent phosphorus limits
  • Provide year round certainty for wastewater treatment and discharge


Dedicated to your priorities and needs, every member of our team practices The Probst Proven Process, ensuring that our clients’ best interests are at the center of every decision we make.

Utilizing a the collective expertise of the Probst Operations, Engineering, and Regulatory teams, multiple options for cost reduction associated with sludge handling were explored and presented to facility owners.  

Some of the options explored included mechanical upgrades to the facility or seeking variances to Wisconsin Administrative Code.

Working closely with Wisconsin Department of Natural Resources, the Probst team found another potential solution that would allow for cost reduction and benefit the environment.; Classifying the solids generated from the treatment process as a fertilizer with the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP).


Probst managed all facets of pursuing and obtaining the fertilizer designation including:

  • Managing permitting and licensing process with DATCP
  • Developed relationships with local farmers and local  haulers to identify and secure partners interested in receiving the fertilizer
  • Implemented new reporting procedures with WDNR to  maintain compliance with the facility’s WPDES permit
  • Developed a tracking procedure for hauled fertilizer

In the first month of implementation, sludge hauling and disposal costs have been reduced by nearly $30,000.

Focusing on the unique needs of every client and every project, The Probst Group was able to provide the ideal solution for the centralized treatment facility. Utilizing our teams vast wastewater expertise and working closely with regulatory agencies allowed Probst to provide a first-of-its-kind regulatory pathway to reuse valuable nutrients produced during the wastewater treatment process to save $100k+ in operating costs annually.

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