California Wastewater Treatment Operator Practice Exam

What is a common method of odor control in wastewater treatment facilities?

1. Incineration of organic waste

2. Chemical scrubbing or biofiltration

3. Limiting access to the treatment area

4. Increasing the flow rate of wastewater

The correct answer is: Chemical scrubbing or biofiltration

Effective odor control in wastewater treatment facilities is essential for maintaining air quality and reducing nuisance complaints from surrounding communities. Chemical scrubbing and biofiltration are widely recognized methods used to manage odorous emissions. Chemical scrubbing involves using specific chemicals to neutralize or absorb odorous compounds in the air. For instance, sodium hydroxide can be employed to remove hydrogen sulfide, a common odorant in wastewater. By passing odorous air through a scrubbing solution, the undesirable compounds are either dissolved or chemically transformed, significantly reducing their presence and, consequently, the odors emitted. Biofiltration, on the other hand, utilizes microorganisms in a filter medium to break down organic odorous compounds. The polluted air is passed through a moist medium, such as compost or peat, where bacteria metabolize the odor-causing substances as a food source. This method is particularly effective for treating a broad spectrum of volatile organic compounds found in wastewater treatment processes. In contrast, incineration involves burning waste material, which does not directly target the control of odors from treatment facilities. While limiting access to treatment areas may help reduce exposure to odors, it does not eliminate the odors themselves. Increasing the flow rate of wastewater can affect the treatment process but is not a recognized or effective method