Process may be viable alternative to costly construction for sewer separation
SOUTH BEND — A decade after the federal government first told cities to start reducing the sewage that overflows into rivers and streams, much work remains to be done in South Bend and hundreds of other cities.
The primary reason is the cost and difficulty involved. The city of South Bend figures it could ultimately need to spend more than $300 million to satisfy the U.S. Environmental Protection Agency, which wants E. coli bacteria levels in the St. Joseph River and Lake Michigan reduced.
On top of the enormous cost, separating all combined storm and sanitary sewer lines would cause major disruptions, as streets and property throughout the city would need to be ripped open.
But what if the city could achieve the same results — sending less sewage into the river during wet weather and reducing the number of flooded city basements — without all that new sewer line construction?
Jeffrey Talley, assistant professor of civil engineering and geological sciences at the University of Notre Dame, thinks that is possible. He is leading a research effort, using South Bend’s sewer system as his laboratory, that would use a network of embedded wireless sensors inside sewer pipes to measure water levels during wet weather. If a pipe fills up with rain or melted snow, the sensor would send a radio message alerting a “smart valve” to open and send water into other pipes with more room.
The water would remain there until the wet weather event subsides and then would slowly be released to the city’s sewage plant for treatment and discharge into the river.
“There’s a lot of in-line storage in the system that doesn’t get utilized,” Talley said.
His team, financed by a $1 million state grant, in September installed the first test applications of the technology at two test sites: one in a below-ground sewer near Walnut and Euclid streets, and the other in a storm water retention pond southwest of Miami and Ireland roads.
The initial data has been promising, Talley said.
If the city agrees to implement the network throughout its sewer system, Talley believes it might only need to spend 10 percent to 30 percent of the roughly $300 million the city expects it will ultimately need to meet federal mandates.
Gary Gilot, the city’s public works director, said the city is keenly interested in the concept but believes Talley’s forecast might be overly optimistic.
“That would be exciting news if that comes to pass,” Gilot said. “I’m not sure if I see that. I’ll be a doubting Thomas and say I’m not sure it would be that kind of a dramatic result.”
But Gilot said citywide implementation of the network, should its potential be fully realized, would probably save taxpayers “millions” of dollars.
Gilot said he is particularly fascinated by two of Talley’s ideas that go beyond sensors detecting the flow of water in the sewer lines. Those sensors already exist. Talley’s team is working to develop new sensors that would detect contaminants such as E. coli, the city’s biggest regulatory problem when it comes to the river.
Further down the road, Talley envisions sensors that could protect against terrorism by detecting biological and chemical toxins in the water supply.
Gilot also said he, along with IDEM and EPA officials, are also intrigued by the research team’s work on mini-treatment facilities near combined sewer overflow outfalls. Under that scenario, rather than slowly releasing water stored in underused pipes to the treatment plant, devices would release enzymes into the pipe to break down pollutants and hydrogen peroxide to disinfect the water. It would then be discharged directly into the river without ever going to the plant.
Ever since National Public Radio first reported on his project last year, Talley said he has been contacted by cities from around the world, including Paris, New York, Chicago, Detroit and Los Angeles. Initially he was inundated with e-mails and was receiving 15 calls a day from people wanting to learn more, he said.
One of those inquiries came from Milwaukee-based Johnson Controls Inc., which is negotiating with the University of Notre Dame to license the patent for the process and commercialize it.
Brad Van Meter, municipal utilities solutions manager with the company, said he sees a potential $1 trillion world market for the process. If the pilot project in South Bend proves the Talley team’s theories correct, Johnson Controls wants to start marketing it nationwide.
“It is a huge market across North America,” Van Meter said. “We’re a very interested participant … we see it as a fix for South Bend’s immediate needs but also as a live proving ground for technology that can be used elsewhere.”