Fig 1 Combined Sewer Operation During Heavy Rainfall

Fig 1 Combined Sewer Operation During Heavy Rainfall

In a combined sewer system, one pipe carries both sanitary and stormwater flow. During dry weather, the sanitary flow is carried to the wastewater treatment plant. During heavy rainfall, if the sewer system is full, it is designed to overflow at designated outfalls to nearby waterways to avoid flooding basements or streets. (image from https: //ecoss.org)