A major advantage of using acid in wastewater treatment is:

Using acid in wastewater treatment primarily serves to neutralize bases, which contributes significantly to maintaining the pH balance of the water. Many wastewater treatment processes are sensitive to pH levels, and ensuring the correct acidity is crucial for the effectiveness of biological treatment systems and chemical reactions. For instance, some wastewater can be alkaline due to the presence of industrial effluents, which can hinder biological processes that require a specific pH range for optimal microbial activity.

When acids are added to treat wastewater, they can lower the pH and neutralize any excessive alkalinity, promoting a more favorable environment for bacteria and other microorganisms involved in the treatment. Proper pH control helps in optimizing the conditions under which these microorganisms thrive, ultimately leading to improved treatment efficacy.

While the other choices may present positive attributes associated with specific processes in wastewater treatment, they do not directly relate to the primary benefit of acid use in this context as effectively as the ability to neutralize bases does.