Tennessee Wastewater Operator Practice Exam

Which type of trickling filter media is least susceptible to plugging?

1. Horizontal flow

2. Vertical flow

3. Plastic media

4. Organic media

The correct answer is: Vertical flow

The correct choice is vertical flow for trickling filter media that is least susceptible to plugging. In a vertical flow trickling filter, wastewater passes downward through the media due to gravity. This design allows for better drainage and minimizes the retention of solids that can lead to clogging. Since the flow is directed vertically, the solids tend to settle out more readily, which reduces the risk of accumulation within the filter media. In contrast, horizontal flow filters can be more prone to plugging because wastewater flows horizontally across the media surface, creating conditions that can lead to the buildup of organic materials and solids on the media, thereby increasing the potential for clogging. Plastic media can also be less susceptible to plugging compared to organic media, as plastic does not decompose and can provide smoother surfaces. However, plastic media is still vulnerable to biofilm buildup and could eventually clog if not properly maintained. Organic media, while benefiting from biodegradation, is more prone to decay and subsequent accumulation of solids, making it more susceptible to plugging over time.