Texas Wastewater Class B Practice Exam

The correct answer highlights a key aspect of aeration performance. Decreased pressure at air diffusers indicates that there may be an issue with the air supply in the aeration tank, suggesting that the system is not delivering adequate oxygen to support the biological processes needed for effective wastewater treatment. Aeration relies on the proper distribution of air to facilitate the growth of microorganisms that break down organic matter; thus, if the pressure drops, the efficiency of this process can be compromised.

Other aspects of the question touch on potential symptoms of aeration problems but don't specifically signal poor aeration as directly as decreased pressure at air diffusers. Change in color or the development of a scum layer can signify issues like nutrient imbalance or other chemical changes, while high levels of sediment accumulation often indicate settling issues rather than aeration deficiencies. These symptoms can arise from various other factors in the overall wastewater treatment process, making them less specific indicators of aeration problems compared to the pressure at diffusers.