You may have seen semi-trucks in your neighborhood with a “Metrogro” logo on the tanker.
What is Metrogro? Metrogro is the treated, solid material collected from Madison Metropolitan
Sewerage District’s wastewater stream. Metrogro biosolids contain organic material and nutrients
recycled onto farmland as a valuable fertilizer.
The District collects wastewater from communities throughout Dane County, including
communities near Sun Prairie such as Waunakee, Deforest, Cottage Grove and Madison. (Note that the
City of Sun Prairie are not part of the District but are served by Sun Prairie’s local wastewater treatment
facility.) The District also has a large septage receiving program where material from private septic tanks
is brought in by a septage hauler to be processed at the treatment plant. This important service allows
waste from rural septic tanks to be digested to reduce bacteria levels, create biogas, and become part of
the biosolids product, Metrogro.
The District’s mission is to protect public health and the environment, and we take that mission
seriously. Safety, accuracy and efficiency are top priorities for all staff, from the team that works with
those in our community to reduce pollutants from entering our sewer system and the lab staff that
analyzes the material to the workers that inspect, flag and coordinate field application of Metrogro.
Every field that receives Metrogro is permitted with the Wisconsin Department of Natural Resources
and inspected and flagged by an agronomist. Fields are inspected and flagged for environmentally
sensitive features, such as streams, shallow bedrock and high-water tables. We also flag setbacks from
homes and private wells . All application rates are based on the University of Wisconsin nutrient
application recommendations, including consideration for the field’s soil type and crop rotation.
The Metrogro program has been in place since the 1970s. A lot has changed during that time,
not only within the program but also with local farming practices. More recently, farmers have placed
greater importance on soil health, with preferences toward less tillage, less soil compaction, and better
management of nutrients. Metrogro is working to keep up with farmer expectations by researching
other forms of biosolids, including dewatered biosolids and composted biosolids. This fall, the District
partnered with Bradley Farms, University Extension, and the Yahara Pride Farms farmer-led watershed
group to install a research plot on Pierceville Road.The project’s goal is to identify each product’s impact
on nutrient availability and soil health . We are hopeful that some of these alternative products will
reduce the number of semi-trucks on the township roads, soil loss and soil compaction during biosolids
application, but that they will also improve soil structure, infiltration and soil biology and allow for more
precise recycling of nutrients within the food system. The project will continue throughout the 2022
crop season.
More information can be found on the Metrogro program at www.madsewer.org.
If you’d like to learn about a water quality initiative in the Yahara Watershed that brings farmers,
municipalities and wastewater treatment plants together to improve water quality, check out
www.yaharawins.org.