Basic Wastewater Operator Practice Exam

In which system is chlorine commonly used for disinfection?

1. Aerobic treatment systems

2. Activated sludge systems

3. Trickling filters

4. Lagoon systems

The correct answer is: Activated sludge systems

Chlorine is commonly used for disinfection in activated sludge systems due to its effectiveness in eliminating pathogens from the treated wastewater before it is released into the environment or reused. In these systems, the activated sludge process involves aerating wastewater to promote the growth of microorganisms that break down organic matter. After the treatment process, chlorination is employed as a crucial step to ensure that any harmful bacteria, viruses, or other pathogens are effectively killed. Using chlorine in activated sludge systems provides a reliable method for disinfection, helping to comply with health and environmental regulations aimed at protecting public health. While other systems like aerobic treatment, trickling filters, and lagoon systems may utilize disinfection, activated sludge systems are particularly noted for the routine application of chlorine as an integral part of their treatment process, making it a standard practice for ensuring wastewater safety before discharge.