The production and use of biosolids are carefully monitored to ensure a high quality product to protect the environment and meet farmers’ needs.
Quality control starts before wastewater reaches the treatment plant. WLSSD’s industrial pretreatment program sets limits on chemicals that industries can discharge to the sewer. Pollution prevention programs help residents and smaller businesses keep unwanted chemicals out of wastewater.
As a result, the levels of metals in WLSSD’s biosolids are far below strictest U.S. Environmental Protection Agency standards. WLSSD tests its biosolids regularly to make sure standards are met.
WLSSD’s certified operators deliver and spread Field Green® biosolids. Fields are inspected before being added to the program to identify soils and water features. Not all fields are suitable for biosolids.
Field Green® crews calculate how much biosolids can be spread on each field, based on crop requirements and field size. Computer databases and maps are used to calculate the acreage of each field and determine buffer zones from water features, such as wetlands. GPS technology is used in the field to stay out of buffer zones and to spread the correct amount of biosolids.
The University of Minnesota Extension has studied the benefits of using biosolids.
Those studies have found that biosolids:
The Biosolids Digest newsletter is produced twice annually by WLSSD for farmers, landowners, and other interested parties.