Wastewater New York State Practice Exam

In a trickling filter, the purpose of the media is to:

1. Provide surface area for microbial growth

2. Filter out large solids

3. Enhance chemical reactions

4. Increase water retention time

The correct answer is: Provide surface area for microbial growth

In a trickling filter, the primary function of the media is to provide a substantial surface area for microbial growth. This allows for the development of biofilms containing microorganisms that are essential for the biological treatment of wastewater. As wastewater flows over the media, the microbes in the biofilm break down organic matter and other pollutants effectively. The design and material of the media are optimized to maximize the surface area while allowing adequate air circulation and water flow, which are crucial for the metabolic processes of the microbes. While filtering out large solids is an important aspect of wastewater treatment, this function is typically handled by pre-treatment processes, such as screening, rather than the trickling filter itself. Enhancing chemical reactions is not the primary role of the media, as biological processes drive the treatment in a trickling filter. Similarly, while some retention of water occurs, increasing water retention time is not the main purpose of the media; the focus is on promoting microbial interactions with the wastewater for efficient treatment. Thus, the correct understanding revolves around the optimization of conditions for microbial growth on the filter media.