Tennessee Wastewater Operator Practice Exam

Which chemical is commonly used to decrease effluent pH before discharge?

1. Hydrochloric acid

2. Acetic acid

3. Sulfuric acid

4. Phosphoric acid

The correct answer is: Sulfuric acid

The most commonly used chemical to decrease effluent pH before discharge is sulfuric acid. This substance is effective because it is a strong acid that can rapidly lower the pH of wastewater, ensuring compliance with effluent discharge regulations. In wastewater treatment processes, maintaining the appropriate pH level is crucial for both the efficiency of biological treatment processes and regulatory compliance when discharging the treated water into receiving bodies. Sulfuric acid's effectiveness in this role makes it a widely accepted choice among wastewater treatment facilities. It is also advantageous due to its availability and cost-effectiveness relative to other acids. Additionally, sulfuric acid can assist in coagulation and flocculation processes in wastewater treatment, further enhancing its utility in adjusting pH levels. Other acids such as hydrochloric acid, acetic acid, and phosphoric acid may also be used in certain situations, but sulfuric acid is typically favored for its strong acid characteristics and efficiency in lowering pH in larger volumes of wastewater.