California Wastewater Treatment Operator Practice Exam

What defines the role of a biosolid?

1. Untreated sewage sludge that can pose health risks

2. Treated sewage sludge that can be safely recycled as fertilizer

3. A byproduct of chemical treatment processes

4. Solid waste generated from industrial sources

The correct answer is: Treated sewage sludge that can be safely recycled as fertilizer

The role of a biosolid is defined by its nature as treated sewage sludge that has been processed to remove pathogens and reduce its bulk, making it safe for recycling and use as a fertilizer. This transformation means that biosolids can contribute nutrients back to the soil, supporting agricultural practices and improving soil health. The treatment process ensures that any hazardous components are minimized to levels that pose no significant risk to human health or the environment when used appropriately. Biosolids must meet specific regulatory standards to be recycled effectively, emphasizing the importance of treatment processes that enhance their safety and utility. This differentiates them from untreated sewage sludge, which carries health risks due to the potential presence of harmful pathogens and contaminants. Moreover, biosolids are distinct from industrial solid wastes and byproducts of chemical treatments, as they originate specifically from the sewage treatment process and are managed to recover their value for use in agriculture and land reclamation.