What are biosolids and how are they different from sewage sludge?
Biosolids are solid, semi-solid or liquid materials, resulting from treatment of domestic sewage, that have been sufficiently processed to permit these materials to be safely land-applied. The term was introduced by the wastewater treatment industry in the early 1990’s and has been recently adopted by the United States Environmental Protection Agency (U.S. EPA) to distinguish high quality, treated sewage sludge from raw sewage sludge and from sewage sludge containing large amounts of pollutants. Some groups have charged that the term “biosolids” has been employed to disguise the real nature of sewage sludge from the general public, thereby reducing objections to land application of sewage sludge. Although “biosolids” does not evoke the same negative connotation as does “sewage sludge,” the use of the term is appropriate when it makes the distinction described above.
