In some buildings in Philadelphia, water flushed down the toilet flows directly into the water supply.
In these buildings, “human waste, shower water, dirty dish grease, and other stuff that belongs in the sanitary sewer system is going down the wrong pipe, sending it to waterways that feed the Delaware River — the city’s primary source of drinking water. The city does filter and treat the water it draws from the river, so drinking water would not be contaminated,” The Philadelphia Inquirer reported.
The problem is something known as a “cross-connection,” which refers to a pipe that feeds into the wrong location, according to The Inquirer. In this case, sewage is being rerouted into environmental drinking water sources.
“Between showers, toilet flushes, and sink use, a typical Philadelphia resident uses up to 85 gallons of water a day. That equates to about 272 gallons a day for a typical Philadelphia home — and if there’s a cross-connection, that could mean 100,000 gallons going into the river each year,” the report said.
Philadelphia water department workers have been on the hunt for cross-connections for years.
“Water department crews had methodically worked their way up to a block on Ainslie Street, about half a mile from the river, looking for the home, or homes, that were producing the sewage. On a bitterly cold day last week, the crew spent hours outside on their detective work, literally following their noses. They opened manhole after manhole before they at last smelled sewage in one storm drain. Bingo. The crew had found the street that was the source,” the report said.
Cross-connections are just one of Philly’s pipe challenges. Like many older cities, Philadelphia has a combined sewer system, which brings a large swath of challenges.
“Unlike in more modern cities like Austin or San Diego, where the storm water pipes are separate from the sewage pipes, in Philadelphia the two run together. Sometimes there's too much flow for the system to handle. It hasn't helped that since these old sewers were built much of the land in cities has been paved over, making far more stormwater than the system's creators had anticipated. There's another problem with the outmoded Philly system: Once sewage and water are combined, the whole mixture must be treated,” Popular Mechanics reported.
But the Philadelphia system has strengths, as well.
“Instead of building larger sewers and new treatment plants, Philadelphia decided to put its chips on what environmentalists call nature-based infrastructure. It has built hundreds of subsurface storage projects, rain gardens, planters, stormwater tree trenches, porous pavement projects, swales and green roofs that reuse stormwater or intercept it and let it absorb into the ground or evaporate,” The Chicago Sun-Times reported.
“Seven years into its 25-year Green City, Clean Waters project, the city’s green engineering system now manages to keep 1.5 billion gallons of polluted water from running each year into the Schuylkill and Delaware rivers and smaller waterways,” the report said.
Image credit: "philadelphia skyline," r’lyeh imaging © 2008, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/