What is the normal air-to-water ratio at peak flow in a packed tower aerator?

• A. 15:1
• B. 20:1
• C. 25:1
• D. 30:1

Answer: (C)

The normal air-to-water ratio at peak flow in a packed tower aerator is essential because it directly influences the efficiency of the aeration process. The packed tower aerator relies on maximizing the surface area for gas exchange, and the air-to-water ratio is critical in achieving that.

A ratio of 25:1 suggests that for every 25 parts of air, there is 1 part of water. This ratio allows sufficient contact between the air and water, enhancing the stripping of volatile compounds from the water and increasing oxygen transfer, which is vital for processes such as wastewater treatment.

Higher ratios like the one provided emphasize the need for effective aeration to ensure that drinking water or treated water reaches appropriate quality standards. While other lower ratios exist (such as 15:1 or 20:1), they may not provide the same level of efficiency necessary for peak operational conditions, where maximum removal of contaminants and adequate oxygenation are required. Thus, the 25:1 ratio reflects a balance that optimizes both airflow and contact time in the aeration process.