California Wastewater Treatment Operator Practice Exam

What is a common method to enhance the disinfection of wastewater?

1. Adding excess nutrients

2. Utilizing chlorine gas

3. Implementing UV light

4. Employing sedimentation processes

The correct answer is: Implementing UV light

Utilizing UV light is a common method to enhance the disinfection of wastewater due to its ability to inactivate a wide range of pathogens without adding chemicals to the water. UV light works by disrupting the DNA of microorganisms, rendering them unable to reproduce and causing them to lose their infectious capabilities. This method is effective against bacteria, viruses, and protozoa, providing a reliable means of ensuring that treated water is safe for discharge into the environment or for reuse. This approach to disinfection is advantageous because it avoids the formation of potentially harmful by-products associated with chemical disinfection methods, such as chlorination. Additionally, UV disinfection is typically quicker and can be easily integrated into existing treatment systems. While chlorine gas is also an effective disinfectant, it can create harmful by-products, such as trihalomethanes (THMs). Similarly, sedimentation processes are essential for removing solids but do not inherently provide disinfection. Adding excess nutrients does not contribute to disinfection and can potentially cause other environmental issues. Therefore, implementing UV light stands out as a prominent and effective strategy for enhancing wastewater disinfection.