Which chemical is often used to adjust pH in wastewater treatment?

Sodium hydroxide is a commonly used chemical for adjusting pH in wastewater treatment. It functions as a strong base and is effective in raising the pH of acidic wastewater. In many wastewater treatment processes, maintaining the proper pH is crucial for optimizing biological treatment, enhancing precipitations, and improving the efficiency of chemical reactions.

When wastewater has a low pH, it can harm microbial populations crucial for biological treatment processes and may lead to the release of toxic substances. By adding sodium hydroxide, operators can neutralize acidic conditions and ensure that the wastewater is within the optimal pH range, which is typically between 6.5 and 8.5 for most biological processes.

Other chemicals listed, such as chlorine, ammonia, and hydrogen sulfide, serve different purposes in wastewater treatment. Chlorine is mainly used for disinfection, ammonia can be a byproduct in some treatment processes, and hydrogen sulfide is often a concern due to its odor and toxicity rather than a pH adjustment measure. Therefore, sodium hydroxide stands out as the appropriate choice for pH adjustment in wastewater treatment.