Monday, August 17, 2015
It is Not Your Imagination, WSSC Pipe Failure Has Increased
Last Wednesday, August 12, 2015, a 20-inch pressurized sewer main on Rose Theatre Circle in Olney broke causing 270,791 gallons of raw sewage to flow from the pipe and from sewer manholes. Within three and a half hours of the break the Olney Wastewater Pumping Station was shut down to stop the sewage flow so the pipe could be repaired. However, shutting down the Olney Wastewater Pumping Station did not stop the sewage from entering the system and manholes in the area began to overflow with sewage after a couple of hours and did not stop until after the Olney pumping station was put back in service. WSSC brought in septic haulers that were able to prevent approximately an additional 123,425 gallons of sewage from overflowing into the nearby waterways.
This sewage spill may sound a bit familiar, but it is new. What you are recalling is that on Tuesday, July 28, 2015 a different section of the same 20 inch pressurized sewer main began leaking. It was Wednesday morning, July 29th before WSSC stopped the leak and by then about 460,000 gallons of raw sewage had been spilled. Within an hour the same 20 inch sewer main had sprung another leak about 100 feet away and another 534,000 gallons of sewage was spilled before that leak was stopped. WSSC repair crews located the second leak and repairs to the main were completed on Thursday, July 30th. Now less than 2 weeks later another section of the pipe is leaking.
This is the third break in this sewer 20 inch diameter pressurized sewer pipe in two weeks. Though there were 160 sewer “overflows” in 2014, most of these were caused by blockages in the pipes from grease, tree roots, and debris not pipe failure. Sewer pipe failure, though less frequent cause’s larger spills, this is especially true of sewer pipes that flow under pressure. On Friday WSSC used closed circuit television cameras to examine the pressured sewer main and surprise, it found severe deterioration of the pipe. WSSC has hired a consultant to inspect the condition of the entire main and see if there are more leaks and is planning to develop a comprehensive solution that will eliminate future breaks. WSSC plans to insert a camera inside the pipe to better assess the condition of the sewer main to help determine a long-term solution. After three breaks in the same sewer main, replacing the entire sewer main seems like a sensible long-term solution.
WSSC emphasizes that the water and wastewater systems are separate. The sewage spill will not impact drinking water in anyway. However, the drinking water distribution system is in only slightly better condition than the sewer system. Last Wednesday while dealing with the Olney sewer problem, WSSC had two 90-year-old water main pipes break. The first break, in a 12 inch water main located on East-West Highway at Route 1 in Prince George’s County, was repaired fairly quickly restoring water service to all area customers. The second break in a 10 inch water main, at Flower Avenue and Piney Branch Road in Montgomery County, needed to have Washington Gas fix a gas line before repairs can be completed.
These pipe breaks last week during the summer serve to highlight the issue of aging infrastructure in WSSC’s system. Though, WSSC is currently replacing about 55 miles of water mains per year and 274 miles of sewer pipe over a 12 year period, that is not enough. That rate of pipe replacement would replace the sewer system in 236 years and the water system in 101 years. Pipes do not last that long. WSSC reports that approximately 37% of the water system delivery pipes are over 50 years old. Though age is not the only factor that causes pipe failure, most of the system’s pipes were designed for an average lifespan of 65 years. The break rate for pipes increases after 60 years. Age alone, however, cannot always be used as an indicator of failure, but it is a good predictor in warm weather breaks. There is a relationship between water temperature and pipe breaks. A sudden temperature drop provides a kind of shock to the pipes. Water temperature below 40 degrees Fahrenheit can also cause pipes to become more brittle, and break. That leads to increased pipe breaks in the winter, and why water utilities typically report their February number of breaks- when most breaks take place.
Established in 1918, WSSC is one of the largest water and wastewater utilities in the nation, with a network of nearly 5,600 miles of fresh water pipeline and over 5,400 miles of sewer pipeline. For decades WSSC has deferred maintaining their piping systems, choosing instead to repair pipes as they failed. It is not your imagination, the piping is failing more frequently and is about to get worse. Much of the WSSC’s service areas was built out in the building boom of 1960s and continuing through the late 1980s. The pipes installed in 1960 are 55 years old, in the next decades WSSC will have to replace a significant portion of their piping systems. Over the next 10 years WSSC will have to replace over 2,000 miles of water pipe and similar amount or sewer pipes. WSSC estimates that they will have to spend over $2.6 billion dollars in the next five years on capital improvement projects and has been studying how to pay for those needs.