Wastewater Treatment Operator Certification Practice Test

During the day, what typically happens to a pond as a result of the algae?

1. Algae uses carbon dioxide, which raises pH

2. Algae produces carbon dioxide, which lowers pH

3. Algae consumes carbon dioxide, which lowers pH

4. Algae releases carbon dioxide, which raises pH

The correct answer is: Algae uses carbon dioxide, which raises pH

During the day, algae in a pond engage in photosynthesis. This process consumes carbon dioxide (CO2) from the water to produce oxygen and organic matter. As the algae use up CO2, the concentration of carbonic acid in the water decreases, leading to an increase in pH. A rise in pH indicates a more alkaline condition, which can occur in the presence of active algal growth during daylight hours. This interaction between algae and carbon dioxide underscores the dynamic relationship in aquatic ecosystems, where the productivity of algae influences the chemical properties of the water. Understanding this process is crucial for wastewater treatment operators, as it helps manage water quality and prevent issues such as pH imbalances that can impact aquatic life and treatment efficiency.