Complaints are pouring in on social media and to local officials about something foul wafting through the air in Louisville. Some say it smells of rotten eggs and sulfur, others are blaming their pets.
“I just accused my dog of pooping in the house! I owe him an apology!” wrote Patti Olsen in the Germantown-Schnitzelburg Facebook group. “I kept on saying I smelled poop!”
The smells point in one direction. Down. Into the sewers. That rotten egg odor comes from hydrogen sulfide, a common sewer gas that forms when sewage and other organic matter decomposes.
The Metropolitan Sewer District recorded 30 odor complaints in July, 71 in August and has so far received 185 complaints in September. Similarly, the city’s air pollution regulators have tracked “well over 100 reports” related to sewer odors since last Friday, said Matthew Mudd, spokesperson for the Air Pollution Control District.
“While there had been an uptick in reports this month, that is really the point where we started seeing what we believe is an unprecedented number of reports in this short of a time period,” Mudd said.
Mostly, the smells stay in the sewers, but these last few weeks have been warm and dry. Long stretches without rain dry out the sewers, especially in the older parts of the system known as the combined sewer system that mostly resides within Interstate-264.
The combined sewer system has nearly 70,000 catch basins that help prevent odors from escaping. These basins function similar to the pipe under your kitchen sink, which has a curve in it designed to trap a small amount of water that keeps the gases from rising out of your drain. If the traps dry out, the smells abscond.
Odor control
Some parts of the city have it worse than others. Foul sewer odors are more common in Parkland, Chickasaw, Park DuValle and parts of Shawnee and Russell. These communities are closest to the state’s largest wastewater treatment plant, Morris Forman, and since the vast majority of the sewage in the combined sewer systems is gravity-fed to the treatment plant, the ZIP code of 40211 deals with the largest volume of sewage. That sewage has also been in the system the longest and often smells worse.
Park DuValle is one of the communities that has been dealing with this problem for years. That’s in part because developers never built catch basins in the community. At one time, MSD identified more than 1,000 untrapped catch basins in five West End neighborhoods.
Just this summer, MSD replaced 22 catch basins in Park DuValle, said MSD spokesperson Sheryl Lauder. The sewer district has put out a bid to replace catch basins in the California neighborhood next.
A little rain
September is one of the driest months of the year in Louisville. The city only received about a tenth to a quarter inch of rain over the last week or two, which is about average. That, combined with the warm temperatures earlier this month, exacerbated the smell problems across the city.
“Well it’s no longer hot, but it’s still dry, and hot and dry combos are not the best friends of our combined sewer system,” Lauder said. “What we really need to take care of the problem across the city, probably county wide, is a little bit of rain... would be great.”
People can report smells on MSD’s website, and they’ll come out and take a whiff and put in a work order. Lauder also suggested that residents might try using a hose to fill the catch basin near their home, if it’s smelly.
Otherwise, the city’s at the whims of the weather. National Weather Service Louisville Science and Operations Officer Ryan Sharp said it’s possible Kentucky could see a spot of rain this weekend from the outer edge of Hurricane Ian.
“But here in Louisville it’s not going to be a lot of rain, maybe a tenth up to a quarter of an inch,” Sharp said.
