Biosolids Fact Sheet
What are Biosolids?
Biosolids are the nutrient-rich organic product of wastewater treatment. A beneficial resource, biosolids contain essential plant nutrient and organic matter and are recycled as a fertilizer and soil amendment.
Wastewater treatment processes are taken right out of nature's recipe book. In streams and lakes natural aeration helps to purify the water while microorganisms break down solids. Wastewater treatment uses the same idea; the liquid portion is treated and returned to streams, lakes, or oceans, and the solids are further processed into stable organic material, called biosolids.
Everyone contributes directly or indirectly to biosolids. Both businesses and households, whether connected to sewer systems or on septic tanks, generate biosolids. Today, modern treatment processes and strict controls on discharges to sewers contribute to high quality, recyclable biosolids.
Recycling biosolids is good for the environment. Organic matter has been recycled for centuries to improve soil fertility and productivity. When properly applied and managed, biosolids can:
- provide essential plant nutrients
- improve soil structure and tilth
- add organic matter
- enhance moisture retention
- reduce soil erosion
Biosolids recycling is regulated and encouraged by the United State Environmental Protection Agency and the Michigan Department of Environmental Quality. Research and years of recycling experience have demonstrated that properly managed land application of biosolids is environmentally safe.
Biosolids recycled in agriculture provide essential plant nutrients such as nitrogen, phosphorus, and zinc for healthy crops. Biosolids promote root growth by improving soil tilth, enhancing moisture retention, and encouraging earthworms. Biosolids supply organic matter and often improve yields, both of which help control soil erosion. Biosolids recycling can play an important role in soil fertilization and conservation.
Biosolids improve forest productivity, increase growth of hybrid poplars and enhance the aesthetic value of Christmas trees. Where biosolids have been used, the trees grow faster than those living in unfertilized soils. Wildlife populations often increase in these areas because the understory vegetation is more abundant.
Severely disturbed soils can be reclaimed through the addition of biosolids to replace lost topsoil. Biosolids have been used successfully to reclaim surface strip mines, large construction sites, parks, wetlands and landfills. Biosolids improve soil fertility and stability, aiding revegetation and decreasing erosion.
Biosolids composted with sawdust, wood chips, yard clippings, or crop residues make excellent mulches and topsoils for horticultural and landscaping purposes. Many professional landscapers use composted biosolids for landscaping new homes and businesses. Home gardeners also find composted biosolids to be an excellent addition to planting beds and gardens.
Contact: Michigan Department of Agriculture
P.O. Box 30017
Lansing, MI 48909
Michigan Department of Agriculture
Environmental Stewardship Division
Biosolids Fact Sheet