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Biosolids

Sewage Sludge Surveys

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Sewage sludge surveys identify the presence of pollutants in biosolids using samples taken from wastewater treatment plants (WWTP). This information is used in assessing potential risk from pollutants found in biosolids to human health and the environment.

Sewage sludge that is treated and meets federal and state regulations is often termed ‘biosolids’. 40 CFR Part 503 defines sewage sludge as a solid, semisolid, or liquid residue generated during the treatment of domestic sewage in a treatment works (for example a wastewater treatment plant (WWTP). Domestic sewage and wastewater from homes, businesses, and industries enter WWTP where the sewage and water are separated and treated. Sewage sludge includes scum or solids removed in primary, secondary, or advanced wastewater treatment processes and any material derived from sewage sludge (e.g., a blended sewage sludge/fertilizer product) but does not include grit and screenings or ash generated by the firing of sewage sludge in an incinerator.

2009 Targeted National Sewage Sludge Survey (TNSSS)

The Targeted National Sewage Sludge Survey was conducted from 2006-2007 to obtain national estimates of the concentrations of pollutants identified in sewage sludge for use in assessing their potential risk to human health and the environment. EPA focused on publicly owned treatment works (POTWs) that treat more than one million gallons of wastewater per day and which collectively generate approximately 94% of the wastewater flow in the United States.

2001 National Sewage Sludge Survey

The 2001 National Sewage Sludge Survey was conducted to obtain national estimates of concentrations of dioxin and dioxin-like compounds in sewage sludge to use in assessing their potential risk to human and ecological health as a result of biosolids land application, surface disposal and incineration.

1988 National Sewage Sludge Survey

The results of the 1988 National Sewage Sludge Survey were used to assess potential risk to human health and the environment from pollutants found in biosolids in support of the 1993 regulation 40 CFR Part 503, Standards for the Use or Disposal of Sewage Sludge.

Studies Related to the Sewage Sludge Surveys​

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