Sewage treatment is a critical process in modern sanitation and environmental management. It involves the removal of contaminants from wastewater, making it safe for discharge into the environment or for reuse. One of the most vital components of sewage treatment is bacteria. These microorganisms play an essential role in breaking down organic matter, purifying water, and maintaining ecological balance. This article explores the importance of bacteria in sewage treatment, detailing their functions, benefits, and the processes involved.