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Sniffing Out Sewage Where It Doesn't Belong


Trained dogs assist with a variety of human endeavors.

Some guide people with vision impairments.

Police use other breeds to detect narcotics.

Now two trained dogs are busy in the Milwaukee area – sniffing out human waste in storm pipes.

The operation is part of the bigger effort underway here to prevent sewage from mixing with storm water.

The blend can end up in rivers and Lake Michigan during torrential rains.

However, scientists are finding sewage in storm sewers, even during fair weather – that’s where the dogs come in.

WUWM Environmental Reporter Susan Bence met the canine brigade during its first Milwaukee area mission.

A torrential downpour in summer of 2010 flooded basements in Shorewood and propelled the village on an expensive overhaul of its century-old sewer system.

Civil engineer Mustafa Emir says the community soon realized its underground maze was leaking all the time.

A UWM scientist discovered traces of human waste at the end of pipes delivering storm water to Lake Michigan – during non-storm stretches.

But bringing dogs into the picture was not part of Shorewood’s original plan.

“We wrote a grant application to the EPA to investigate the sources of this contamination and implement improvements to stop it,” Emir says.

The Environmental Protection Agency awarded the grant and suggested the village check into the services Karen and Scott Reynolds provide.

The Michigan couple trains scent dogs – normally, to help with search and rescue operations or to detect illegal drugs.

“And my boss walked up to me one day and he said, hey do you think you could train a dog to smell poop. Well initially I laughed,” Reynolds says.

A Shorewood public works worker pops off a manhole cover east of Oakland Avenue.

The Reynolds each walk a leashed dog passed the exposed storm sewer.


If Sable smells anything fishy, he barks. Logan’s response is to sit.

Scott Reynolds boasts their sniffing power to be over 90 percent accurate.

This spot elicits a positive response from both dogs.

Civil engineer Mustafa Emir says the “findings” bring the village a step closer to diagnosis.

“With that information, we’re going narrow it down, as you can see there are only five homes from here to there, so it must be one of those,” Emir says.

Normally, to identify “hot spots”, crews lower cameras into manholes or inject dye or smoke into neighborhood pipes and laterals.

Those methods are expensive – and planners have a hard time sorting out which locations to inspect for leakage first.

The dogs can sniff quite a few in a short time, narrowing the list of locations warranting intensive investigation.

Researcher Sandra McLellan of the UWM School of Freshwater Sciences wastes no time.

She dangles a bucket tethered to a long cord, down into the storm sewer the dogs identified.

I caught up with McLellan earlier this week by phone.

She is encouraged about the potential role canine testing might play, but admits she did not gather enough samples in Shorewood to draw conclusions.

Her team drew multiple samples this week from storm sewers near the Menomonee River – also being sniffed out by the dogs - to determine whether they contain human bacteria.

McLellan will analyze spots deemed positive by the dogs as well as others at which they turned up their noses.

“We hope by next week we can start comparing what the dogs found versus what we found and kind of map it and start looking at some factors like, at low concentrations were the dogs able to pick it up. Was there some kind of depth of a sewer or some kind other factors that play a role in their ability to either pick it up or not pick it up under certain circumstances,” McLellan says.

The scientist believes there is room for “trained dogs” in zeroing in on faulty sewage lines.

“What we’re looking for is do they pick up any false positives, because you don’t want to be chasing something that’s not there. We have so many problems that if miss the low level stuff and really get the high level stuff, that’s actually more useful than if they picked up everything, because we know that there is a lot out there,” McLellan says.

McLellan says with so much in need of repair or replacement, why not start with the “worst parts” and mend those.

McLellan’s findings may have a direct impact on Michigan dog trainers Karen and Scott Reynolds whose newfound expertise may be in even higher demand.

“When we originally started this whole thing, I mean we have the experience in dog training, but it’s like why reinvent the wheel, why not build on what they did, nothing, couldn’t find anything. We don’t know of anyone else who’s doing it,” Reynolds says.

The couple says it took them roughly a year to train Sable and Logan to react, when sniffing human waste in pipes.