What is the purpose of aeration in the secondary treatment stage?

Aeration plays a crucial role in the secondary treatment stage of sewage treatment by providing oxygen to microorganisms that break down organic pollutants present in the wastewater. This process is essential because these microorganisms require oxygen to thrive and effectively decompose organic materials, such as food waste and other biodegradable substances.

By enhancing the oxygen levels in the treatment system, aeration supports aerobic digestion, which is more efficient in removing organic matter compared to anaerobic processes. This results in the production of carbon dioxide, water, and biomass, which helps in reducing the overall pollution load of the effluent before it is discharged or subjected to further treatment stages. Effective aeration optimizes the activity of these beneficial microorganisms, leading to improved water quality and compliance with environmental standards.

In contrast, options related to facilitating chemical reactions, removing solid waste, or concentrating nutrients don’t align with the primary purpose of the aeration process in secondary treatment. Aeration is specifically focused on promoting the biological treatment of wastewater by supplying the necessary oxygen for microbial activity.