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bioweb.sungrant.org » Technical » Biomass Resources » Urban Biomass Resources » Biosolids

Biosolids	Printer Friendly

Biosolids are the organic materials resulting from the treatment of sewage in municipal wastewater treatment facilities. Sewage sludge is the material resulting from settling and screening of solid materials in sewage. Biosolids differ from sewage sludge in that they undergo additional physical, chemical, and biological processing to control odors, remove disease-causing pathogens (bacteria and viruses), toxins, disease carriers (rodents, flies), and bind some heavy metals. The type and level of wastewater treatment affects the type, quantity, and quality of the biosolids generated. An estimated 6.9 million dry tons of biosolids were generated in 1998. It is projected that by 2010, 8.2 million dry tons will be generated (EPA, 1999; NBP, 2007). Approximately 60% of the material was used, either to produce compost or applied to land as fertilizer (regulated under 40 CFR Part 503). About 17% was disposed of in landfills.   Biosolids contain 10,000 to 12,000 Btus of energy per dry pound and can be used to produce heat, steam, and electricity (WEF, 2007). About 1.5 million dry tons of biosolids were used for energy production in 1988 (EPA, 1999). About 150 municipalities combust biosolids, but anaerobic digestion and gasification technologies can also be used (WEF, 2007).

References
U.S. Environmental Protection Agency, Office of Solid Waste, Biosolids Generation, Use, and Disposal in the United States, EPA530-R-99-009, September 1999. National Biosolids Partnership, www.biosolids.org. Water Environment Federation, Bioenergy from Waste Water Treatment, 2007, www.wef.org.