What are the two main products of anaerobic digestion of sludge?

• A. Stabilized Biosolids And Biogas
• B. Raw Sludge And Oxygen
• C. Sludge Foam And Methane
• D. Water And Nitrogen

Answer: (A)

Two main products of anaerobic digestion of sludge are biogas and stabilized biosolids. In the absence of oxygen, microorganisms break down the organic matter to produce biogas, a energy-rich mixture primarily of methane and carbon dioxide. The remaining solid material becomes stabilized biosolids, which have reduced pathogens and odors and can be reused as soil amendment or disposed of under regulations. Oxygen isn’t produced in this process, raw sludge isn’t the result of digestion, and sludge foam isn’t a defined main product; while methane is part of biogas, the other main product is the stabilized biosolids, not another byproduct like foam. Water and nitrogen aren’t the primary outputs of anaerobic digestion.