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.
Summary of Federal Requirements
40 CFR 503 establishes rules for the final use or disposal of sewage sludge (biosolids) when biosolids are:
Applied to land to condition the soil or fertilize crops or other vegetation grown in the soil;
Placed on a surface disposal site for final disposal
Fired in a biosolids incinerator.
The land application and the surface disposal of sewage sludge is regulated to prevent the transmission of disease or contaminants to humans or groundwater. As such, pre-application testing requirements, contaminant limitations, application rates, disposal volumes, and application locations are strictly regulated in 40 CFR 503.