Feeling flushed: Sewerage District employees keep things flowing
Ever wonder what happens after you flush?
Here’s the poop.
We might consider it “out of sight, out of mind,” but once flushed down a toilet, our waste begins a slow slog through a vast network of pipelines toward the Nine Springs Treatment Plant on South Towne Drive, where it will either be treated and discharged or converted to fertilizer or natural gas. Along its journey, a handful of Madison Metropolitan Sewerage District employees regularly monitor the putrid flow. The data they collect will help determine how much municipalities will be billed each quarter for wastewater treatment.
Behind Copps on Monona Drive, James Barkenhagen, 28, a monitoring services and sewer maintenance worker, readies for the descent. He slips on a special blue bodysuit followed by hip boots, gloves, and a helmet with a headlamp.
His colleague, Monitoring Services Crew Leader Robert Ploessl, 61, has already removed the 100-pound manhole cover, dropped an air sensor deep into the hole, and set up a portable, metal tripod over the opening.
They wait for the sensor to check for danger signs — hydrogen sulfite, carbon dioxide, low oxygen, or explosive material. Barkenhagen wears an identical sensor over his shoulder. With the all-clear, Ploessl hooks Barkenhagen’s harness to a cable on the tripod and lowers him into the hole. They always travel in pairs for safety: One person goes down, the other stays up top.
On this day, Ray Schneider, 56, collection system supervisor, joins them. His four-man crew works on the other side of the flush, going underground to monitor the volume of raw sewage flowing as deep as 30 feet under the street and determining if any dangerous and/or unwanted substances are hitching a ride.
James Barkenhagen is lowered into a manhole on the city's west side.
About 12 feet underground, Barkenhagen crouches next to a moving stream of wastewater. The area he works in is about 6 feet around, but some areas can be much tighter. This is not a job for the claustrophobic (and a poor sense of smell might help!).
Barkenhagen installs a weir made of wood and metal into the half-pipe to dam up the flow of waste, building pressure. The height of the water that subsequently escapes over a V-notch at the top of the weir calculates the flow rate, per gallon.
They also install a barrel-shaped “sampler” into the hole that is programmed to collect samples of wastewater over a 24-hour period. The crew will return for the samples for seven consecutive days and also record the flow rate at each visit. There are more than 100 sampling locations in MMSD’s 180-square-mile sewerage district, and each is monitored quarterly.
Back at MMSD’s lab, the water samples are analyzed for biochemical oxygen demand, or BOD, which is the amount of oxygen required by aerobic microorganisms to decompose organic matter. A community with a lot of dairy waste, for example, generates a higher BOD reading and therefore is charged more per gallon. Municipal bills are also adjusted based on the amount per pound of phosphorous, ammonia, suspended solids, or other chemicals found in the water.
Manholes allow access to the underground sewer system, where 96 miles of gravity lines move waste from Madison and other municipalities to 17 regional pumping stations. The region’s relatively flat terrain requires the district to pump wastewater through 29 miles of pressurized force mains.
It costs MMSD more than $1 million a year to keep the pumps running.
The Nine Springs Treatment Plant treats about 42 million gallons of wastewater every day. The treated liquids, or effluent, are discharged in two locations: Badfish Creek, which bypasses the Madison lakes but ends up in the Rock River to the south, and to a smaller degree Badger Mill Creek in Verona, which eventually flows into the Sugar River watershed. The effluent is monitored daily, and the discharge points into the creeks are also tested regularly to assure compliance with DNR and EPA guidelines.
MMSD’s service area includes Madison and stretches as far north as Morrisonville, east to Cottage Grove, south to Kegonsa, over to Fitchburg, and southwest to Verona and Middleton. MMSD does not serve Sun Prairie, Stoughton, or Oregon.
In the bowels of the city
Employees receive confined space training every year for one-way-in, one-way-out situations. “We learn about different explosives, gases, and hazardous materials we may come in contact with, or a lack of air,” said Schneider, “and what not to do if you have a fallen buddy.” If Barkenhagen were to pass out, for example, Ploessl could attempt to retrieve him by pulling him up through the chimney of the manhole, but under no circumstances is he allowed to go down to rescue his colleague. That work is left to emergency responders.
There are other risks as well. Though they haven’t encountered any rats, they do encounter their fair share of mice and snakes. Barkenhagen does not like mice, and Schneider can’t stand snakes.
“I was down in the hole once taking a measurement and a big bullsnake was in the water. It didn’t look like a ‘floater.’ His head popped out of the water. … I didn’t think I could crawl out of a 10-foot manhole that fast!” recalled a still-squirming Schneider. The 4-foot snake, he learned later, was dead, but it didn’t matter.
The team replaces the manhole cover and heads to another location near Glenway Golf Course. They might visit as many as a dozen locations in a day. This particular manhole is decidedly older. The brick “chimney” leading underground shows some decay, which is not surprising since much of the city’s infrastructure has existed since the 1930s, Schneider notes, and is being upgraded as necessary by MMSD maintenance staff.
Again, Barkenhagen gets lowered inside. This hole is just 8 feet below the street’s surface, and daylight allows a better glimpse at what’s flowing underneath. Wastewater includes everything flushed down toilets or drains from household cleaning, bathing, and cooking, as well as industrial cleaning and manufacturing. Heavy rain events will also infiltrate the flow.
Toilet paper floats by his feet, followed by chunks of human waste. He uses a tool to push it through the weir’s V-notch. “Was that an oatmeal and raisin cookie?” they joke, “or a fiber bar?” A sense of humor is a must in this job.
This particular site is also part of an independent, three-month study on chloride, which treatment plants cannot remove, and the men check that a chloride sensor is working properly. The biggest chloride offenders, they explain, are inefficient water softeners and road salt.
Going with the flow
Barkenhagen is hoisted out of the hole. Does he feel clean at the end of the day? “It depends on how dirty I get,” he says, matter-of-factly. “Most of the time, it’s just sweat.” It’s always warm down below, and humid. He showers at the plant before heading home. “These suits protect me really good, and I always use hand sanitizer. I’m constantly cleaning my arms and hands.”
This is the last day of Barkenhagen’s two-week rotation on the monitoring team. He’ll spend the next four weeks on the sewer maintenance team. It keeps the job interesting, they agree.
The staff regularly goes into pipelines, “televising” deep inside and checking for problems. Because of the likely dangers, employees are immunized against tetanus and hepatitis. Rubber gloves do not always protect against glass, or worse, needles flushed down toilets.
And there are other surprises lurking below. They’ve tracked illegal dumping of paint and have also found rags, two-by-fours, a bowling ball, and animals, including kittens, in the lines.
“Flushable” cleansing wipes cause problems. “They don’t break down,” Schneider says. “Toilet paper degrades, baby wipes or sanitary wipes do not.”
And grease? You should never put it down the sink or disposal, whether in a liquid form or not.
This team, members of AFSCME Local 60, works six days a week regardless of weather, and they all seem to really enjoy their jobs.
“Every day, it’s something different,” said Schneider. Ploessl, a 35-year veteran, shrugs. “We see what kind of diets people have, and some aren’t very good. But someone’s got to do it.”
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