Tennessee Wastewater Operator Practice Exam

What method is used to remove a blockage from a jet aeration system nozzle?

1. Backflush by filling the header with air

2. Manual cleaning

3. Flush with high-pressure water

4. Use of chemicals

The correct answer is: Backflush by filling the header with air

The method of removing a blockage from a jet aeration system nozzle using backflushing by filling the header with air is effective because it creates a pressure differential that helps dislodge and clear any obstructions. This technique exploits the physical properties of air under pressure, allowing for the build-up of force against the blockage without the need for physical contact or additional tools, which might risk damaging the system. In contrast, manual cleaning could be labor-intensive and may not be feasible for nozzles that are difficult to access. Flushing with high-pressure water can also be effective but may not always be safe for all components of the system and could lead to other issues, such as erosion of the materials. The use of chemicals may not be applicable in all cases, particularly if the blockages are physical debris or biofilm that require mechanical removal rather than chemical dissolution. Therefore, backflushing with air is a safe, efficient, and non-invasive method for maintaining the performance of the jet aeration system.