Which type of treatment process directly requires oxygen?

The type of treatment process that directly requires oxygen is aerobic processes. In these processes, microorganisms break down organic matter in the presence of oxygen. This is essential for the metabolic activities of aerobic bacteria, which utilize oxygen to convert organic pollutants into carbon dioxide, water, and other beneficial byproducts. The presence of oxygen enhances the efficiency of the treatment, allowing for faster decomposition and stabilization of waste materials.

Anaerobic processes, in contrast, do not utilize oxygen and rely on microorganisms that function in low or no oxygen environments. Thermal processes involve applying heat to destroy or reduce contaminants but do not specifically rely on oxygen. Chemical processes may involve the introduction of various chemicals to treat the wastewater but also do not inherently require oxygen to facilitate the treatment procedure. Thus, aerobic processes are distinctive for their oxygen requirement, which is fundamental to their operation and effectiveness in wastewater treatment.