What is the primary method for odor control in sewage treatment plants?

Covering treatment units is the primary method for odor control in sewage treatment plants because it effectively contains and isolates the odors produced during sewage treatment processes. By enclosing the treatment units, such as tanks or reactors, the release of odorous gases into the atmosphere is significantly minimized. This method not only helps to prevent unpleasant smells from escaping into the surrounding environment but also allows for easy management of the odorous air, which can then be treated before being released, further reducing the impact of odors.

While methods like chlorination and pH adjustment are important in managing water quality and disinfection, they do not primarily focus on odor control. Aeration, although it is crucial in promoting the breakdown of organic matter and maintaining aerobic conditions, can sometimes inadvertently increase the release of odors by disrupting sediments and allowing gases to escape. Therefore, covering treatment units stands out as a direct and effective way to tackle the issue of odors in sewage treatment operations.