Which components are key to secondary treatment in wastewater treatment?

Secondary treatment in wastewater treatment primarily focuses on the removal of organic matter and pollutants through biological processes. Activated sludge is a key component of this stage, utilizing microorganisms to break down and consume organic contaminants present in the wastewater. This method effectively reduces biochemical oxygen demand (BOD) and suspended solids, making the water cleaner and safer for discharge or further treatment.

The use of biological processes is essential here as it allows for a natural, eco-friendly approach to treating wastewater, promoting sustainable practices. The activated sludge process involves aerating the wastewater, which encourages the growth of bacteria that digest the organic materials. This is a distinct advantage over other methods that might involve physical or chemical treatments that do not leverage biological activity as effectively. Overall, the use of activated sludge is a hallmark of secondary treatment, making it the correct choice in this context.