NEHA Wastewater Practice Test – Complete Exam Prep 2025

Aerobic bacteria are primarily responsible for aerobic digestion in sewage treatment because they thrive in oxygen-rich environments and utilize molecular oxygen to break down organic matter. This process allows them to efficiently decompose waste materials, converting them into simpler substances while producing energy for their own growth and reproduction.

During aerobic digestion, these bacteria metabolize organic compounds in the sewage, leading to the production of carbon dioxide, water, and biomass. The presence of oxygen is crucial in this process, as it enables aerobic bacteria to perform cellular respiration, which is more energy-efficient compared to anaerobic processes. This energy obtained aids in their metabolic activities, leading to effective waste treatment.

In contrast, pathogenic bacteria are associated with disease and do not play a significant role in the treatment process. Facultative bacteria can operate in both aerobic and anaerobic conditions but are not the primary agents in aerobic digestion. Anaerobic bacteria function in the absence of oxygen and are involved in different stages of the wastewater treatment process, particularly in anaerobic digestion, which focuses on breaking down organic matter without oxygen. Hence, aerobic bacteria are the key players in aerobic digestion during sewage treatment.