Biosolids Basics

Biosolids are the nutrient-rich organic by-product of municipal wastewater treatment that can be beneficially and safely recycled. Used by both the U.S. Environmental Protection Agency (EPA) and the Water Environment Federation (WEF), biosolids is a specific term to describe only those wastewater solids that meet the most stringent state and federal regulations and are, therefore, considered safe for use as fertilizer and as a soil amendment to improve and maintain productive soils and stimulate plant growth. The term “biosolids” is defined in both the Webster’s and Oxford Dictionaries.

• Past
• Present
• Future

Thirty years ago, thousands of American cities disposed of their raw sewage directly into the nation’s rivers, lakes and other public waterways. Through regulation of this dumping, local governments now are required to treat wastewater and decide whether to recycle biosolids through land application and other methods or to pursue alternatives such as incineration and landfilling, the latter generally deemed less desirable solutions.

Recycling biosolids is not a new management concept. In the United States, it is as old as farm reclamation, even as old as wind-, solar- and hydro-generated power sources. In some European countries, almost all biosolids are applied on agricultural land. Today, thousands of municipalities in all 50 U.S. states successfully recycle their biosolids using innovative technologies. These technologies reflect 30-plus years of concerted scientific research and documented field tests designed to gain a better understanding of the benefits of biosolids recycling.

Biosolids also are the result of more than a decade of detailed EPA risk assessment studies and extensive evaluation of advanced scientific data. One example is a 20-year-plus study for the EPA at the University of Arizona that supports the benefits and safety of biosolids. This and other well-documented research findings constitute the scientific basis for the current state and federal regulations governing biosolids.

As required by the Clean Water Act amendments of 1987, EPA developed a comprehensive regulation to safeguard public health and the environment from any reasonably anticipated adverse effects of certain pollutants that might be present in biosolids. In 1993, Title 40 CFR, Part 503 (Part 503 rule) was published in the Federal Register (58 FR 9248 to 9404) and since then has undergone several revisions. (For a concise explanation of the rule, see “A Plain English Guide to the EPA Part 503 Biosolids Rule”

The official position on biosolids at EPA’s Office of Wastewater is that when managed according to federal and state regulations, “the treated residuals from wastewater treatment, or biosolids, can be safely recycled.” Most recently, in the Office of Inspector General Status Report on the land application of biosolids, issued March 28, 2002, EPA reiterated its strong support.

Both EPA and WEF cite numerous environmental and economic benefits of biosolids recycling. While helping local governments meet the challenge of managing their wastewater treatment residuals, the practice provides a cost-effective, organic alternative to chemical fertilizers.

To further strengthen the framework within which to responsibly manage biosolids, the biosolids industry and other practitioners have developed voluntary performance practices to complement the Part 503 rule. There exists today, for example, an organized communications network for sharing innovation and information on management practices and policies.

Biosolids contractors, producers and users who are members of the National Biosolids Partnership (NBP) also recently developed a biosolids environmental management system (EMS). EMS is a tool for defining verification strategies and program oversight, and for demonstrating to communities that biosolids meet regulatory performance standards. (For the most recent NBP EMS documents available online, see EMS Guidance.)

A survey of biosolids coordinators in the United States by the Journal of Composting & Organics Recycling: BioCycle in 2000 indicated that almost half of the states responding recycled more than 50 percent of the biosolids they generated.

Looking ahead, the EPA and WEF anticipate that the beneficial recycling of biosolids will steadily increase. In 2000, an estimated 7.1 million tons, or 63 percent of all biosolids generated, were recycled. By 2005, that amount is expected to reach 7.6 million tons (66 percent of the total) and 8.2 million tons (70 percent) by 2010.

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Biosolids Benefits

The Part 503 Rule


About Biosolids

Biosolids Basics
Industry overview;
the science now; its future.

Environmental and economic
advantages of biosolids

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Common Concerns
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Origin of “biosolids” name...

While the practice it describes is not entirely new, the word "biosolids" is. Its use started a little more than a decade ago. The Water Environment Federation (WEF) solicited suggestions for a name after water quality professionals searched for a new expression to more accurately describe the treated sewage sludge that could be used for agriculture and as a soil amendment. "Biosolids," an abbreviated variation on the biological processing of wastewater solids, was one of 300 responses to WEF's call for suggestions. WEF formally recognized the term in 1991 and most state and federal agencies use it today.

• Water Environment Federation
• U.S. Environmental Protection Agency


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