Ace the California Wastewater Treatment Operator Exam 2025 – Dive In and Purify Your Career!

A combined sewer system operates by collecting both sewage and stormwater in a single pipe. This design allows municipalities to manage both types of wastewater concurrently, particularly during periods of rainfall when stormwater runoff can significantly increase the volume of water that needs to be conveyed and treated.

In a combined system, during dry weather, the sewage is routed to a treatment facility, and stormwater flows are typically minimal. However, during heavy rain events, the volume of stormwater can exceed the capacity of the treatment plant, leading to potential overflow situations. This can result in combined sewer overflows (CSOs), where untreated sewage and stormwater are discharged into nearby water bodies. Understanding the operation of a combined sewer system is crucial for managing water quality and infrastructure in urban areas.

The other options do not accurately represent the functionality of combined sewer systems: separating stormwater and sewage refers to separate sewer systems, treating stormwater prior to sewage is not a characteristic of combined systems, and utilizing double pipes for redundancy does not correlate with how combined systems are designed to function.