Biosolids

Decontaminated sewage sludge Pumpkin seedlings planted out on windrows of composted biosolids Biosolids are solid organic matter recovered from a sewage treatment process and used as fertilizer. In the past, it was common for farmers to use animal manure to improve their soil fertility. In the 1920s, the farming community began also to use sewage sludge from local wastewater treatment plants. Scientific research over many years has confirmed that these biosolids contain similar nutrients to those in animal manures. Biosolids that are used as fertilizer in farming are usually treated to help to prevent disease-causing pathogens from spreading to the public. Some sewage sludge can not qualify as biosolids due to persistent, bioaccumulative and toxic chemicals, radionuclides, and heavy metals at levels sufficient to contaminate soil and water when applied to land. Terminology Biosolids may be defined as organic wastewater solids that can be reused after suitable sewage sludge treatment processes leading to sludge stabilization, such as anaerobic digestion and composting. Alternatively, the definition of biosolids may be restricted by local regulations to wastewater solids only after t