California Wastewater Treatment Operator Practice Exam

The primary function of algae in a wastewater treatment pond during the daytime is indeed the release of oxygen for aerobic bacteria. During photosynthesis, which occurs when there is sunlight, algae take in carbon dioxide and water, using light energy to produce glucose and oxygen. This oxygen is then released into the water, providing a crucial resource for aerobic bacteria that are responsible for breaking down organic matter in the wastewater.

The presence of oxygen is essential for aerobic processes, which are more efficient in breaking down waste compared to anaerobic processes. This interaction supports the overall biological treatment of wastewater, improving the efficiency of the pond system. The symbiotic relationship between algae and aerobic bacteria helps in maintaining a balanced ecosystem within the treatment pond.

In contrast, other functions such as the release of methane gas, ammonia, or hydrogen sulfide occur under different conditions or by different microorganisms. Methane production, for example, typically takes place under anaerobic conditions when organic matter is decomposed without oxygen, which is not the primary function during daylight hours when photosynthesis is active.