What type of wastewater collection system carries both sanitary wastewater and stormwater runoff?

The combined system is a type of wastewater collection system designed to carry both sanitary wastewater and stormwater runoff within the same pipeline infrastructure. This system operates by integrating sewage from homes and businesses with rainwater runoff from surfaces such as streets and roofs.

During dry weather, the combined system effectively transports regular wastewater to treatment facilities. However, during heavy rainfall, this system can face challenges, as the influx of stormwater can overwhelm the capacity of the treatment plants, sometimes leading to combined sewer overflows (CSOs). These occurrences can result in untreated wastewater being discharged into local water bodies, which is a significant environmental concern.

The other options refer to different configurations: a separate system is designed exclusively for sanitary sewage or stormwater, an advanced system typically involves treatment technologies that enhance wastewater processing, and a single-line system is not a standard term used within wastewater management context.