Florida Wastewater Practice Test

Where is the rock in trickling filters typically placed?

1. On the surface of the filter bed

2. On system tile under drains

3. Above the water level

4. Within the filter media

The correct answer is: On system tile under drains

In a trickling filter, rock is typically placed on the system tile under drains for several reasons. This placement allows for efficient drainage and ensures that effluent can flow away from the filter media. The rock layer acts as a supportive base that facilitates the movement of leachate, helping to prevent clogging and ensuring proper aeration within the filter. This setup improves the treatment process by maintaining optimal conditions for the growth of microorganisms that break down organic matter in the wastewater. Placing the rock within the filter media or on the surface of the filter bed would disrupt the intended filtration and aeration processes. Additionally, positioning the rock above the water level would hinder the flow of water through the system, potentially leading to problems with treatment efficiency.