Wastewater Treatment Operator Certification Practice Test

Which of the following could be the cause of ponding in a trickling filter?

1. Hydraulic loading is too low

2. Clogging of distributor orifices

3. Excessive organic loading

4. Denitrification

The correct answer is: Excessive organic loading

Ponding in a trickling filter is primarily associated with excessive organic loading. When the organic load is too high, it can overwhelm the microbial population residing on the filter media, leading to inefficient treatment and potential buildup of biomass. This can create conditions where the flow of water through the media slows down, resulting in ponding. In trickling filters, the performance depends on a balanced relationship between the hydraulic loading (the volume of water flowing through the filter) and the organic loading (the amount of organic material in the wastewater). If the organic loading increases without a corresponding increase in hydraulic flow, it can lead to saturation of the media, decreased oxygen availability, and eventual ponding. The other conditions mentioned, such as low hydraulic loading or clogging of distributor orifices, can impact the system but are not typically the primary causes of ponding. Proper management of organic loads is essential in maintaining the effectiveness of trickling filters and preventing ponding issues.