Which of the following is a common method to control odors in wastewater treatment?

Using covers and scrubbing systems is an effective method for controlling odors in wastewater treatment facilities. This approach works by enclosing odor-producing processes or tanks, which helps to contain and prevent the escape of odorous gases. The covers not only help to isolate the source of odors but also can be integrated with scrubbing systems that treat the collected air. These scrubbing systems typically use a chemical solution to neutralize or absorb the odorous compounds from the air before it is released into the environment. This combined method effectively reduces the impact of unpleasant smells to the surrounding community and helps maintain compliance with environmental regulations regarding air quality.

Other methods listed, such as increasing water flow rates or chemical treatments, may impact the overall treatment process but are not primarily focused on odor control. Reducing the chlorination process could lead to an increase in odors since chlorination is often used to eliminate odor-causing bacteria, so this approach would not effectively manage odor issues.