Municipal Wastewater Treatment Practice Exam

The activated sludge process is a widely utilized secondary treatment method in wastewater treatment that effectively converts both organic matter and ammonia nitrogen. This method involves aerating the wastewater, which provides oxygen to bacteria that break down organic pollutants. The activated sludge system leverages a combination of microorganisms, which consume organic matter as a food source, allowing for the mineralization of organic components.

In addition to organic matter degradation, the activated sludge process plays a crucial role in nitrogen removal. The bacteria involved not only assimilate organic carbon but also convert ammonia nitrogen into nitric and nitrous oxides through nitrification. This process is essential for reducing the nitrogen content of effluent, which is critical for meeting environmental regulations and minimizing eutrophication in receiving waters.

Trickling filters, while effective for organic matter removal, primarily focus on biological treatment through a fixed film of microbes and are less efficient in ammonia nitrogen conversion compared to activated sludge systems. Lagoon systems can also facilitate the removal of organic matter and ammonia but typically do so over longer retention times and are not as controlled or efficient in nitrogen removal as activated sludge. Land application systems can mitigate both nutrients and organic load but depend heavily on soil absorption and take longer to process wastewater effectively.

Thus, the activated sludge process stands out as the