Which process is primarily responsible for the biological breakdown of most organic matter in sewage during wastewater treatment?

• A. Nitrification
• B. Fermentation
• C. Photosynthesis
• D. Aerobic digestion

Answer: (D)

Verified step by step guidance

1. Understand the context of wastewater treatment, where organic matter needs to be biologically broken down to reduce pollution and make the water safe.
2. Review the given options and their roles: Nitrification is the oxidation of ammonia to nitrate, Fermentation is anaerobic breakdown producing gases, Photosynthesis is the process by which plants convert light energy to chemical energy, and Aerobic digestion involves microorganisms breaking down organic matter in the presence of oxygen.
3. Recognize that the primary biological process for breaking down most organic matter in sewage is one that uses oxygen to efficiently decompose complex organic compounds into simpler substances.
4. Identify that aerobic digestion fits this description because it uses aerobic microorganisms to metabolize organic matter, producing carbon dioxide, water, and biomass, thus reducing organic load.
5. Conclude that aerobic digestion is the main process responsible for the biological breakdown of organic matter in sewage during wastewater treatment.