Biosolids are nutrient-rich organic materials resulting from the treatment of domestic sewage in a treatment facility. When treated and processed, these residuals can be recycled and applied as fertilizer to improve and maintain productive soils and stimulate plant growth. Biosolids are treated sewage sludge. Biosolids are carefully treated and monitored and must be used in accordance with regulatory requirements.
EPA offers guidance and technical assistance for the beneficial recycling of biosolids as soil amendments and fertilizer. The use of these valuable materials can enhance:
water quality
pollution prevention
sustainable agriculture.
Sewage sludge that is used in agriculture is regulated under the Clean Water Act, and is currently subject to concentration limits for the following metals:
arsenic
cadmium
copper
lead
mercury
molybdenum
nickel
selenium
zinc.
