During anaerobic decomposition in wastewater treatment, which gas is produced?

During anaerobic decomposition in wastewater treatment, which gas is produced?

• A. Oxygen
• B. Carbon dioxide
• C. Methane
• D. Nitrogen

Answer: (C)

Anaerobic decomposition happens without oxygen, so the microbial processes that dominate this environment generate methane. In wastewater sludge digesters, fermentative microbes break down organics to simpler compounds, and methanogenic archaea convert those substrates—especially acetate and hydrogen with CO2—into methane. That methane becomes the main component of the biogas produced, with carbon dioxide present as well, but the gas most characteristic of this process is methane. Oxygen isn’t produced in these conditions, and nitrogen isn’t a primary product of anaerobic digestion. This is why methane is the correct gas produced in this context.

Anaerobic decomposition happens without oxygen, so the microbial processes that dominate this environment generate methane. In wastewater sludge digesters, fermentative microbes break down organics to simpler compounds, and methanogenic archaea convert those substrates—especially acetate and hydrogen with CO2—into methane. That methane becomes the main component of the biogas produced, with carbon dioxide present as well, but the gas most characteristic of this process is methane. Oxygen isn’t produced in these conditions, and nitrogen isn’t a primary product of anaerobic digestion. This is why methane is the correct gas produced in this context.