What role do bacteria play in the sewage treatment process?

Bacteria play a crucial role in the sewage treatment process primarily by decomposing organic matter and pollutants. This biological treatment is essential for reducing the amount of harmful substances in sewage before it is released into the environment. During this process, specific types of bacteria consume organic material, breaking it down into simpler compounds, and ultimately converting it into non-toxic forms. This microbial activity not only helps in the removal of pollutants but also aids in reducing the biochemical oxygen demand (BOD) of the wastewater, which is a measure of how much oxygen will be consumed by microorganisms in the decomposition of organic material.

By effectively breaking down organic matter, bacteria help in achieving cleaner water that meets regulatory standards for discharge into lakes, rivers, or oceans, thus contributing to environmental protection. Additionally, this process forms the basis of many sewage treatment systems, including activated sludge and trickling filter systems, where bacterial action is fundamental to the treatment efficiency.