About Biosolids and Other Organic Residuals

Biosolids are the nutrient-rich organic byproducts resulting from wastewater treatment. Biosolids have been treated and tested and meet strict federal and state standards for use as fertilizers and soil amendments. Biosolids provide plant nutrients and organic matter to soils. They can also be used to produce energy through digestion and production of methane ("biogas") or drying and combustion, gasification, or pyrolysis.

Residuals are organic "waste" products that can be put to beneficial uses. Biosolids are one kind of residual. Other wastewater residuals commonly recycled in New England and eastern Canada include those generated at pulp and paper mills. Wood ash from electricity generators burning wood chips is another residual; it is used in farming as a replacement for lime.

Download a slideshow about how biosolids are made and used in New England and eastern Canada.