Metrogro Biosolids Program

A valuable fertilizer supporting local agriculture

The District is committed to recovering as many resources as possible from wastewater, including biosolids. Our biosolids product, called Metrogro, is a valuable, nutrient-rich organic fertilizer that supports plant growth and soil fertility.

Before any land application takes place, Metrogro biosolids undergo treatment to control pathogens such as bacteria and other organisms capable of transporting disease. Metrogro biosolids represent a sustainable source of nutrients that support local agriculture and helps farmers and landowners reduce their use of commercial, chemical-based fertilizers.

How Metrogro works

Resource Cycle

Metrogro works in much the same way as other organic manure sources, delivering nitrogen to crops slowly throughout the growing season. This slow-release action means the crop uses more nitrogen, and less is lost to the environment. Metrogro also supplies crops with phosphorus, which is critical for growth.

Metrogro is injected into the soil using large, specialized machinery, which has numerous benefits over land spreading. With injection, applications are precise, and the potential for erosion and runoff is reduced. This assures nutrients are taken up by the crop and not moving to other areas such as wells or surface water. Injection also reduces undesirable odors and is more visually appealing.

The Metrogro team works closely with farmers to meet their needs. Because Wisconsin Department of Natural Resources (WDNR) regulations emphasize nutrient management, Metrogro applications are based on meeting the specific nitrogen requirement of the crop grown. This ensures no over-application of nutrients and reduces the risk of environmental harm through surface runoff or groundwa­ter infiltration.

In addition, District staff carefully consider equipment setup before Metrogro application to minimize field compaction, and crews are careful to leave the fields in good condition for the next crop.

Quality assured

Metrogro is applied to more than 5,000 acres each year. The District documents and reports every load via an annual spreading log sent to WDNR. Metrogro is sampled daily and analyzed for phosphorus, multiple forms of nitrogen, potassium, solids content and 10 metals as part of the quality assurance process. Bacteria samples are also taken during the hauling season.

Federal and state government agencies heavily regulate the Metrogro program and our biosolids, including the U.S. Environmental Protection Agency and WDNR. These regulations are in place to protect communities and the environment while also recovering valuable resources from the biosolids.