How do anaerobic bacteria function in wastewater treatment?

• A. They oxygenate the water to enhance treatment
• B. They metabolize organic matter in the presence of oxygen
• C. They decompose organic matter in the absence of oxygen
• D. They assist in the removal of heavy metals

Answer: (C)

Anaerobic bacteria play a crucial role in wastewater treatment by functioning in environments devoid of oxygen. Their primary activity is the decomposition of organic matter, which is an essential process in breaking down and stabilizing the waste in treatment systems. During this anaerobic process, these bacteria metabolize complex organic compounds and convert them into simpler substances, resulting in the production of biogas, which primarily consists of methane and carbon dioxide. This biogas can be captured and used as a renewable energy source.

By operating in the absence of oxygen, anaerobic bacteria help reduce the volume of waste, lower the overall biochemical oxygen demand (BOD), and contribute to the stabilization of organic materials. Their activity is especially significant in anaerobic digestion systems, where they help transform sludge into digestate, which can be further treated or utilized as fertilizer. The ability of anaerobic bacteria to thrive without oxygen makes them highly effective in specific stages of wastewater treatment processes where oxygen levels are limited.