A system of combined sanitary and storm sewers that directs effluent to a sewage treatment plant during low flows. During rain events excess storm water and sewage is diverted away from the treatment plant to a river or stream. In the late 1940's Minneapolis embarked on a 40year $160 million Combined Sewer Overflow project to guarantee treatment of all sanitary flow and prevent untreated sewage from entering surface waters.
a system of waste removal where storm runoff from streets empties into the same pipes as domestic and industrial wastes. In periods of high rain, the wastewater treatment plant can not handle the increased volume and the wastewater empties through the combined sewer overflows into adjacent waterways without being treated.
A sewer pipe or system through which both sanitary wastewater and stormwater flows. During low frequency storms, both flows remain separate. During higher frequency precipitation events, the stormwater is mixed with the sanitary flow and may bypass wastewater treatment and be released to a receiving water body without treatment.
Discharges of combined sewage and stormwater into water bodies during very wet or storm weather. These discharges occur to relieve the sewer system as it becomes overloaded with normal sewer flow and increased storm run-off. The term is also used to denote a pipe that discharges those overflows.
a discharge from a sewer system that is designed to carry sanitary wastewater and stormwater in the same pipe to a sewage treatment plant
These occur in combined sewer systems when large volumes of water generated during rain events combine with the regular sanitary waste stream, overwhelming the capacity of sewage treatment plants. The resultant sewage overflow goes directly into the Harbor with little or no treatment. See also combined sewer system.
Designed to operate during periods of high rainfall to relieve pressure on sewerage systems. Allows rain water and untreated sewage to bypass the works and flow directly into rivers and coastal waters.
systems that allow untreated municipal sewage to mix and be discharged with storm water, preventing storm water from overwhelming the sewage treatment plant.
During rainfall events, the volume of stormwater entering a combined sewer system often is far greater than the capacity of the interceptor (large collector pipe) and sewage treatment plant and, as a result, the untreated sewage and stormwater mixture empties directly into receiving waters through designated overflow points.
Release to natural waters of partially treated mixture of sewage and street runoff, usually necessary after heavy rain
an opening in a combined sewer where a mixture of wastewater and rainwater can flow out of the sewer into a river or lake. During rainstorms, increased flows can fill up a combined sewer causing the flooding of basements with the wastewater-rainwater mixture if an overflow is not provided.
discharge of a mixture of storm water and sewage when the flow capacity of a sewer system is exceeded during rainstorms.
The release of untreated sewage into streams or rivers when heavy rains cause combined sanitary and storm sewers to fill to capacity and spill over before reaching the sewer treatment plant
Designed discharge from a combined sewer system into a stream. Usually occurs during heavy rainfall.
A pipe that, during storms, discharges untreated wastewater from a sewer system that carries both sanitary wastewater and stormwater. The overflow occurs because a system does not have the capacity to transport and treat the increased flow caused by stormwater runoff.
Wastewater collection system overflows of stormwater and wastewater. This occurs when flows exceed the carrying capacity of the wastewater collection system, such as during heavy rain events.
Flow of wastewater and runoff in a combined sewer in excess of the sewer capacity. It represents the flow that cannot be treated immediately and is frequently discharged directly to a receiving stream without treatment, or to a holding basin for subsequent treatment and disposal.
An event where the discharge of untreated human and industrial sewage and stormwater into local waterways occurs when the capacity of a combined storm/sanitary sewer system is exceeded by local runoff.
The discharge into waterways during rainstorms of untreated sewage and other pollutants via combined sewers carrying both sanitary sewage and storm-water runoff from streets, parking lots, and rooftops.
A mixture of wastewater and runoff found in combined sewers during rainfall or snowmelt events that spills to the environment untreated. CSOs enter the environment either directly or through a storm sewer, as the result of the capacities of the interceptor sewers and/or treatment plants being exceeded. There are 19 CSO locations in Edmonton's combined sewer system.