Thirty years ago, thousands of American cities dumped their raw sewage directly into our
nation's rivers, lakes, and bays. Today, because of improved wastewater treatment, our
waterways have been cleaned up and made safer for recreation and seafood harvest. And,
because of the strict Federal and state standards, the treated residuals from wastewater treatment
(biosolids) can be safely recycled. Local governments make the decision whether to recycle the
biosolids as a fertilizer, incinerate it or bury it in a landfill.
Biosolids are the nutrient-rich organic materials resulting from the treatment of sewage sludge
(the name for the solid, semisolid or liquid untreated residue generated during the treatment of
domestic sewage in a treatment facility). When treated and processed, sewage sludge becomes
biosolids which can be safely recycled and applied as fertilizer to sustainably improve and
maintain productive soils and stimulate plant growth.
Only biosolids that meet the most stringent standards spelled out in the Federal and state rules
can be approved for use as a fertilizer. Now, through a Voluntary Environmental Management
System, being developed for biosolids (EMS) by the National Biosolids Partnership (NBP),
community-friendly practices will also be followed.
Although cities decide how best to manage their biosolids, the U.S. Environmental Protection
Agency (EPA) is obligated and continues to provide the public with educational information,
based on the best science, about the safe recycling and disposal of biosolids.
Frequently Asked Questions
Nomination Guidance 2002 Biosolids Exemplary Management Awards Program
Guide To Field Storage of Biosolids and Other Organic By-Products Used
in Agriculture and for Soil Resource Management
Use and Disposal of Biosolids.
EPA is publishing a final rule for dioxin and dioxin-like compounds (dioxins) in biosolids.
The Federal biosolids rule is contained in 40 CFR Part
503. This rule is described in the EPA publication
Plain English Guide to the EPA Part 503 Biosolids Rule.
The risk assessment for the Federal Part 503 rule that
governs the land application of biosolids took nearly ten
years to complete and had extensive rigorous review and
comment. The risk assessment did evaluate and establish
limits for a number of pollutants. These limits may be
found in chapter four of the EPA publication:
Guide to the Biosolids Risk Assessments for the EPA Part
503 Rule. In the process of establishing these
limits, EPA compared the relevant toxic's exposure data,
which was obtained from a cross section of representative
studies, to the appropriate oral reference dose (RfD) and
human cancer potency (Q1*) values, (i.e., the allowable
dose of ech pollutant.) These exposures were evaluated
via 14 pathways of exposure with the most limiting
pathway being chosen as the limit. In spite of all the
safety factors and uncertainty factors built into the
process, environmental and human health risks were found
to be very low.
EPA Regional and State Biosolids Coordinators
- PublicationsBack to Top
OWM Catalog of
Publications on Biosolids
Sewage Treatment Library
Biosolids (Use or Disposal
The National Biosolids Partnership (NBP) is a voluntary program to promote effective biosolids management involving the Water Environment Federation (WEF), the Association of Metropolitan Sewerage Agencies (AMSA), and U.S. EPA. EPA serves as an advisory member to the Partnership. More information about the NBP can be found at