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What are Biosolids?
Biosolids are, in effect, a slow-release nitrogen fertilizer with low concentrations of other plant nutrients. In addition to significant amounts of nitrogen, biosolids also contain phosphorus, potassium, and essential micronutrients such as zinc and iron. Many western soils are deficient in micronutrients. Biosolids are rich in organic matter that can improve soil quality by improving water holding capacity, soil structure and air and water transport. Proper use of biosolids can ultimately decrease top soil erosion.
When applied at agronomic rates (the rates at which plants require nitrogen during a defined growth period), biosolids provide an economic benefit in addition to their environmental benefits. Colorado State University agronomists have shown continuous application of three dry tons per acre every other year to dryland wheat produces comparable yields, higher protein content, and larger economic returns compared with the use of 50-60 pounds per acre of commercial nitrogen fertilizer.
What are the Traditional Practices in this Region?
Before about 25 years ago, the traditional practice in this Region was to landfill or incinerate what was then called sewage sludge. During the past quarter century the practice changed to recycling biosolids as soil amendments. Region 8 recycles 85% of the biosolids generated in the six state Region. Data from 1996 indicated that 90% of the facilities meet the more restrictive Table III requirements (see 40 CFR Part 503).
How can I get More Information?
Bob Brobst (8P-W-WW), Biosolids Coordinator
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street
Denver, Colorado 80202-1129
Telephone: 303-312-6129 or 1-800-227-8917 ext. 6129
State Contacts for the Biosolids Program