Tennessee Wastewater Operator Practice Exam

According to the state of TN water quality standards, the effluent flow from a wastewater treatment plant shall not change the pH of the receiving stream more than:

1. 0.5 units per 24 hours

2. 1.0 units per 24 hours

3. 2.0 units per 24 hours

4. 3.0 units per 24 hours

The correct answer is: 1.0 units per 24 hours

The requirement that the effluent flow from a wastewater treatment plant shall not change the pH of the receiving stream by more than 1.0 units per 24 hours is established to protect aquatic life and the overall health of the ecosystem. Rapid changes in pH can be harmful to aquatic organisms, which are adapted to stable pH levels. A fluctuation of more than 1.0 unit can stress or potentially kill sensitive species. By setting this limit, the state aims to ensure that any discharge into waterways occurs in a manner that maintains the integrity of the aquatic environment. This standard reflects an understanding of the natural variances in pH that can occur in water bodies and aims to minimize the impact from human activities associated with wastewater discharge. Other choices imply larger permissible changes in pH over the same time frame, which would not align with environmental protection goals and responsible wastewater management.