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PROCESS DESIGN MANUAL: LAND APPLICATION OF SEWAGE SLUDGE AND DOMESTIC SEPTAGE
Citation:
EASTERN RESEARCH GROUP. PROCESS DESIGN MANUAL: LAND APPLICATION OF SEWAGE SLUDGE AND DOMESTIC SEPTAGE. EPA/625/R-95/001 (NTIS PB2000-104369), 1995.
Impact/Purpose:
Information
Description:
Land application of sewage sludge generated by domestic sewage treatment is performed in an environmentally safe and cost–effective manner in many communities. Land application involves taking advantage of the fertilizing and soil conditioning properties of sewage sludge by spreading the sewage sludge on the soil surface, incorporating or injecting the sewage sludge into soil, or spraying the sewage sludge. Because sewage sludge disposal practices (e.g., landfilling) are becoming less available and more costly, and because of the increasing desire to beneficially reuse waste residuals whenever possible, land application is increasingly chosen as a sewage sludge use or disposal practice. Approximately 33 percent of the 5.4 million dry metric tons of sewage sludge generated annually in the United States at publicly owned treatment works (POTWs) is land applied. Of the sewage sludge that is land applied, approximately 67% is land applied on agricultural lands, 3% on forest lands, approximately 9% on reclamation sites, and 9% on public contact sites; 12% is sold or given away in a bag or other container for application to the land (Federal Register, Vol. 58, No. 32, February 19, 1993). In addition, approximately 8.6 billion gallons of domestic septage is generated annually. Land application of sewage sludge has been practiced in many countries for centuries so that the nutrients (e.g., nitrogen, phosphorus) and organic matter in sewage sludge can be beneficially used to grow crops or other vegetation. Over the years, land application has been increasingly managed to protect human health and the environment from various potentially harmful constituents typically found in sewage sludge, such as bacteria, viruses, and other pathogens; metals (e.g., cadmium and lead); toxic organic chemicals (e.g., PCBs); and nutrients (e.g., nitrogen as nitrate). Management of the land application of sewage sludge has included regulatory measures; voluntary and mandatory pretreatment of wastewater and/or sludge by industry to improve quality (e.g., lower pollutant levels); and use of good management practices at land application sites (e.g., buffer zones, slope restrictions).