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.

Sinkholes In America

According to the Infrastructure Report Card from the American Society of Civil Engineers, New York’s waste water infrastructure needs an investment of $21.82 billion over the next 20 years to avoid failure. Just to emphasize the point in Bay Ridge Brooklyn not far from where I once lived in the 1970’s, the street suddenly caved in on August 1st and a 30 foot wide, 10 foot deep sinkhole appeared. This was the second sinkhole in this neighborhood of Brooklyn this year. The earlier sinkhole was twice as large. The city of New York immediately began repairs. According to the City, the sinkhole was caused by a 112 year old sewer pipe that gave way and washed away the soil under the road. The sewer pipe had no doubt been failing for a long time to erode that much soil.

Picture by CBS 2 Bay Ridge, Brooklyn sinkhole

The pipes made early in the 20th century were rated for an 80 year life span. New York sewer piping systems have reached the end of their design lives, but there are no plans of a replacement and upgrade of the system. There has been no systematic replacement program. New York has kept the sewer system alive by repairing what breaks after it breaks and spraying it’s mains with concrete. When the sewer systems were built in the 19th and 20th centuries, the Boroughs of New York still had autonomy and financed and built their own systems to address the problem in the least expensive way, by using a combined storm and sanitary sewer system. The Manhattan and Brooklyn systems were built around the same time modeling the designs of Hamburg, Germany. Nonetheless, the sewers were never designed for the ages, they need to be maintained and upgraded. New York and most of the United States has not maintained and upgraded our sewer systems. According to the U.S. Environmental Protection Agency, EPA, by 2020 half the sewer pipes in the U.S. will be crumbling and the U.S. risks reversing public health, and environmental gains of the past three decades.(Rose George in The Big Necessity, The Unmentionable World of Human Waste and Why it Matters.)

Failing sewer pipes can pose a significant threat to public health and the environment.  Systems with inadequate hydraulic capacity and/or blockages in the sewer pipes may lead to sanitary sewer overflows and sewage backing up into homes or onto streets.  Some of the health hazards associated with basement flooding by untreated wastewater include the potential presence of pathogenic microorganisms such as viruses, bacteria, and protozoa (in a nice moist dark environment). Pipe failures can be grouped into three general categories: hydraulic restrictions (e.g. blockage), hydraulic capacity, and structural condition.

Hydraulic restrictions are the most common problem in wastewater collection systems. Untreated wastewater carries sediment, grease, rags and whatever else you can think to put down the drain or flush down the toilet. The grease congeals with sediment and blockages form. In combined sewers, large items thrown or washed into the storm system create obstructions and restrictions during peak flow times. This can lead to street and basement flooding. Tree root intrusion, sediment accumulation, and grease build-up all contribute to hydraulic restrictions. Aging pipes that sag over time and joints that begin to fail can slow pipe flow and create more favorable conditions for solids to build up in pipes. An ongoing maintenance program for cleaning and flushing sewers is typically adequate to control blockages. However, budgeting for routine preventative maintenance and repairs has not taken place in New York or the rest of the United States. We fix it when it breaks.

Failure caused by inadequate flow capacity is common in combined sewer systems, but may also a sign of other types of problems such as structural defects or design defects. Major sources of pipe structural defects are cracks, broken pipes, and leaks. Pipes sag and sewage does not flow properly, areas of inadequate pipe slope can be due to loss of pipe bedding or inadequate initial slope. Structural failure as in Bay Ridge is typically caused by defects of the pipe wall and/or the soil envelope used to support the pipe.

The EPA reported that the total investment needs of America's publicly owned treatment works as of January 1, 2004, was $202.5 billion and increasing each year. Many systems besides New York have reached the end of their useful design lives, and the nation’s wastewater systems are no longer resilient in their ability to prevent failure, or restore service after a disruption. In addition, the electrical generation and distribution system, the energy sector, contributes to the lack of system’s resilience. Pumps and wastewater treatment plants do not operate without power and reduced reliability of the power supply is increasingly being addressed through the construction of dedicated emergency power generation at wastewater treatment plants and drinking water delivery systems.  Clean and safe water should be the national priority. If we had spent even a quarter of the  $821 billion of the American Recovery and Reinvestment Act of 2009 on the very unglamorous sewers and water treatment systems if the country we would have a cleaner environment, part of our infrastructure would be ready for another century and construction workers would have had jobs.