What are the typical end products of the biological oxidation of organic matter in an aeration basin?

• A. Methane and hydrogen sulfide
• B. Pure oxygen and water
• C. Biomass and CO2
• D. Nitrogen gas and oxygen

Answer: (C)

In an aeration basin, microbes use oxygen to break down organic matter. As they oxidize the carbon, most of it ends up as carbon dioxide and water, and a portion of the organic carbon is incorporated into new microbial cells, creating biomass. So the end products you commonly see are carbon dioxide and biomass, with water also formed during the process. The other options imply anaerobic conditions or different reactions (methane and hydrogen sulfide from anaerobic processes, pure oxygen as a product rather than a byproduct of oxidation, or nitrogen gas from denitrification), which don’t describe what happens in an aerobic oxidation basin.