What are biosolids?

Biosolids refer to the treated organic solids that are removed from wastewater during the treatment process. These solids undergo significant treatment to ensure they are safe and beneficial for use, such as in agriculture as a fertilizer or soil conditioner. The treatment process can include methods like anaerobic digestion, aerobic digestion, and stabilization, which reduce pathogens and pollutants to safe levels.

The clarification of biosolids as treated organic solids distinguishes them from untreated sludge, which is still raw and requires further processing before it can be safely reused or disposed of. This treatment is vital for ensuring that biosolids do not pose health or environmental risks.

In contrast, inorganic materials collected during filtration, such as sand or grit, do not classify as biosolids because they do not derive from organic matter. Liquid waste generated in a treatment plant typically describes effluent wastewater, which is separate from the solid byproducts referred to as biosolids. Understanding these distinctions highlights the importance of biosolids management in sustainable wastewater treatment practices.