When it rains in Pittsburgh, chances are raw sewage will be discharged into its rivers because so many pipes receive not only sewage, but also storm water, and the system can't handle the volume.
When this happens, the Allegheny County Health Departmentissues combined sewer overflow (CSO) flag alerts between May 15 and September 30.
The Allegheny County Sanitary Authority (Alcosan), as required, has submitted a plan to eliminate these discharges and requested time for further study, all of which is under review by the Environmental Protection Administration, with no timetable yet for even beginning to eliminate the problem. Combined sewer overflows will be the reality in the region's rivers for the foreseeable future.
The solution to the problem, according to Alcosan spokesperson Nancy Barylak, is a tunnel system that will accept a lot more flow, but in the meantime, Alcosan is taking steps to improve the situation, such as increasing "wet well" capacity for water going into the treatment plant.
"In our service area, there are streams that empty right into the sewer lines, and we've removed those streams, and thousands of gallons of water, from our system," Barylak said. "There have been some green infrastructure projects, such as rain gardens."
She said lines are also being cleaned to remove debris, which will increase capacity.
To complement the CSO flag alerts, Alcosan issues SOAK(Sewer Overflow Advisory Key) advisories with real-time data about water quality, which Barylak says are useful to boaters, fishermen, kayakers and anyone else who might come in contact with river water.
Jeff Butia, chief of the Public Drinking Water and Waste Management Program at the ACHD, said the big fix of the combined sewer overflow problem will cost hundreds of milllions of dollars, but municipalities with combined sewers are required to take some modest steps that will "improve water quality to a certain extent."
