Which statement best contrasts anaerobic digestion with incineration?

Which statement best contrasts anaerobic digestion with incineration?

• A. Anaerobic digestion occurs without oxygen and produces biogas; incineration uses oxygen to burn waste and generate heat.
• B. Anaerobic digestion requires oxygen; incineration occurs without oxygen.
• C. Both processes produce the same waste outputs.
• D. Anaerobic digestion uses solar energy; incineration uses geothermal energy.

Answer: (A)

The main idea is how these two waste-treatment methods differ in their use of oxygen and what they produce. Anaerobic digestion happens without oxygen; microbes break down organic matter in an oxygen-free environment and generate biogas, a mix mainly of methane and carbon dioxide, which can be captured for energy. The process also yields a digestate that can be used as fertilizer. Incineration, on the other hand, is a combustion process that requires oxygen; waste is burned at high temperatures to release heat, reduce waste volume, and generate energy, while producing ash and flue gases that must be managed. So, the statement that best contrasts them is that anaerobic digestion occurs without oxygen and produces biogas, whereas incineration uses oxygen to burn waste and generate heat. The other options don’t fit because anaerobic digestion does not require oxygen, the outputs are not the same, and the energy sources listed aren’t the defining difference between the two processes.

The main idea is how these two waste-treatment methods differ in their use of oxygen and what they produce. Anaerobic digestion happens without oxygen; microbes break down organic matter in an oxygen-free environment and generate biogas, a mix mainly of methane and carbon dioxide, which can be captured for energy. The process also yields a digestate that can be used as fertilizer. Incineration, on the other hand, is a combustion process that requires oxygen; waste is burned at high temperatures to release heat, reduce waste volume, and generate energy, while producing ash and flue gases that must be managed.

So, the statement that best contrasts them is that anaerobic digestion occurs without oxygen and produces biogas, whereas incineration uses oxygen to burn waste and generate heat. The other options don’t fit because anaerobic digestion does not require oxygen, the outputs are not the same, and the energy sources listed aren’t the defining difference between the two processes.