Which of the following is NOT one of the five basic parts in a trickling filter?

A trickling filter is a type of wastewater treatment system that utilizes microorganisms on a media to treat wastewater as it trickles down through the filter. Understanding its main components is essential for grasping how it operates effectively.

The filter floor, distribution arms, and underdrain system are all integral parts of a trickling filter. The filter floor serves as the foundation supporting the entire system and holds the filter media. The distribution arms evenly distribute the incoming wastewater across the filter media, ensuring that all the microorganisms have sufficient exposure to the wastewater for biological treatment. The underdrain system collects treated effluent and allows it to flow out of the filter for further processing or discharge.

In contrast, an aeration tank is not a component of a trickling filter. Aeration tanks are typically associated with activated sludge processes where air is introduced to mix the wastewater and allow aeration, promoting biological treatment in a different manner. Thus, it is accurate to identify the aeration tank as NOT one of the five basic components of a trickling filter. Understanding the distinct configurations of these systems helps clarify the roles each component plays in wastewater treatment.