Which type of sewer system conveys both sanitary waste and stormwater?

The correct response pertains to combined sewers, which are specifically designed to handle both sanitary waste from residential and commercial sources and stormwater runoff from precipitation events. This design allows for a shared infrastructure that can be more cost-effective in urban areas where space for separate systems may be limited.

Combined sewers work by channeling both types of waste through a single pipe system, typically to a wastewater treatment facility. This can provide advantages in managing the flow of stormwater during heavy rain events by allowing for overflow management, although it can also raise concerns about treatment capacity and the potential for overflow discharges during extreme weather conditions.

In contrast, sanitary sewers are intended exclusively for the conveyance of wastewater generated from sanitary sources, such as toilets and sinks. Storm sewers, on the other hand, are built solely to handle precipitation runoff, directing rainwater away from fields and streets to prevent flooding. Separation sewers refer to systems that have been designed to keep sanitary and stormwater systems distinct from each other, enhancing the efficiency of both conveyance and treatment processes while mitigating overflow risks.

Understanding the functionality and purpose of each sewer type helps clarify why combined sewers uniquely accommodate both stormwater and sanitary waste within a unified system.