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Posted on Fri, Jul 19, 2013 : 5:58 a.m.

Ann Arbor Wastewater Treatment staff evaluating operations after 10K gallon raw sewage spill

By Amy Biolchini


The Ann Arbor Wastewater Treatment Plant at 49 S. Dixboro Road in Ann Arbor Township. The East Plant is the portion on the right that's operational. The West Plant on the left is not operational and is being replaced.

Courtesy of the city of Ann Arbor

The Ann Arbor Wastewater Treatment Plant is evaluating its operations after thousands of gallons of raw sewage spilled into the Huron River during a massive storm event in late June.

Though plant managers attribute the staff’s quick response to preventing a larger spill, an estimated 10,000 gallons of sewage spilled over a 10-minute period beginning about 5:20 p.m. June 27. The June 27 thunderstorm quickly flooded Ann Arbor streets and knocked out power.

Ann Arbor's wastewater plant is at 49 S. Dixboro Road in Ann Arbor Township and treats an average of 18 million gallons of wastewater per day from the city of Ann Arbor and Pittsfield, Scio and Ann Arbor townships. It has an East Plant, built between1977 and 1981, and an older West Plant, which has been taken offline.

At the East Plant, staff noticed the flow rate of wastewater coming into the plant triple in half an hour. They responded by turning on additional pumps to handle the increase in flow, said Keith Sanders, assistant manager at the plant.

By the time the pumps were turned on, workers noticed the sewage spill, Sanders said.

“They saw (the flow rate) rising, they started doing what they needed to do and then they never saw it come back up,” Sanders said. “No one saw it overflow.”

A massive construction project financed by a $120 million bond is underway to replace the West Plant and upgrade the East Plant. Sanders said the construction was not a contributing factor to the spill.

The spill occurred at the point where wastewater flows into the headworks building of the treatment plant.

All of the wastewater flows through a grate and into a concrete trough before entering the plant. The trough is open at the top and is covered by a metal grate.

The raw sewage overflowed the trough and onto the ground, traveling about 100 feet to draining in through storm sewer grate by a roadway, Sanders said.

The storm sewer empties directly into the Huron River upstream of the plant’s outflow pipe, which is at the southeast corner of the treatment plant complex, Sanders said.

Sanders said there was standing water around the plant because of the rainstorm at the time of the spill.

“It’s rare that you see your plant flow triple in half of an hour,” Sanders said. “If you get a storm out of the blue you respond as quickly as you can.”

The wastewater treatment plant is designed to treat 29.8 million gallons per day. On average, Sanders said the plant treats 18 million gallons per day.

The plant is designed to be able to handle short peaks in flow rate that, if extrapolated to a daily rate, would be the equivalent of 66 million gallons in a day.

At the time of the spill, 10,000 gallons were estimated to have spilled in 10 minutes and 350,000 gallons of wastewater were processed.

Officials at the wastewater treatment plant stated the sewage was significantly and immediately diluted once it hit the river swollen by rain. The flow rate in the Huron River in the 10 minutes the spill was estimated to have happened was about 11 million gallons.

Health officials caution individuals to stay out of the Huron River during a major rain event and for the first 48 hours afterward to avoid coming into contact with heightened levels of bacteria and other risk-posing debris in runoff that flows to the river.

Sanders said the staff is evaluating what happened during the incident to see if it could have been prevented. No conclusions have been reached at this time.

“We responded pretty quickly,” Sanders said.

The Michigan Department of Environmental Quality and Washtenaw County Public Health were notified of the spill.

Amy Biolchini covers Washtenaw County, health and environmental issues for Reach her at (734) 623-2552, or on Twitter.



Sat, Jul 20, 2013 : 9:10 p.m.

Raw sewage pouring into the river is a non-event? Wow! I'm so happy the days of polio are behind us. To that little virus, this "non-event" is a beeline to (and into) an unsuspecting public. To all of you parents out there that won't allow your kids to be vaccinated, keep them in house.

Kai Petainen

Fri, Jul 19, 2013 : 9:07 p.m.

Stephen raises a good point about the Dioxane. This is a small case compared to that. Someone mentioned the DNR/EPA/DEQ... where are they? From my experience with the Dioxane and oil, they seem to ignore Ann Arbor. Ann Arbor seems to get a 'free pass' to this sort of stuff. The smaller cases are important because they highlight some of the problems -- one problem deals specifically with the poor communication that exists between these spills and the public. For example, even the HRWC is quiet on this issue. They usually come out and talk about phosphors and ask for money, but each time we have a spill... they stay quiet and they're not quoted in the press. Poor communication and I'd expect them to be condemning this stuff and other spills -- but they're quiet. There was a press release and the press release itself is nicely written, but I should be able to find it on the web without asking people for it. This article in the Ann Arbor news, should have been written much earlier. And if they were unable to write it, then they should have just copy/pasted the press release. Again, poor communication. This city needs to improve on how it notifies the public about spills. It had a chance to learn years ago from an incident -- but sadly, it did not. Something needs to change... because if the present is an example of the future, then we'll be in the dark when that dioxane hits.


Fri, Jul 19, 2013 : 4:51 p.m.

I bet it's made it to Erie by now


Fri, Jul 19, 2013 : 4:23 p.m.

Don't get me wrong. I'm not defending David Kircher in any way, but based on the fact that he was convicted of Substantial Endangerment to Public for water resources protection violations and got 5 years and a $1 million fine for discharging 25,000-100,000 gallons of raw sewage into the Huron River, we should expect to see someone going to jail for between 6 months and 2 years, and being assessed a fine of between $100,000 and $400,000 for this, right? Speaking of David Kircher, he's supposed to get out next month.

Kai Petainen

Fri, Jul 19, 2013 : 3:38 p.m.

This is a repeat offense at poor communication with regards to spills in Ann Arbor. They city has not learned from prior spills and I find that bothersome. The public must be properly notified in the Ann Arbor news and at the canoe liveries. My thoughts were written on paper about this exact spill and I was about to speak at City Hall this past week on this issue. I chose not to, but my thoughts were sent to the Ann Arbor news and to the Chronicle. They are welcome to publish the thoughts, 'My comments to city hall', as an opinion piece if they like.


Fri, Jul 19, 2013 : 3:13 p.m.

. . . so happy I was not in the Huron River within those 48 hours past the spill. Thank you so very much Ann Arbor City Government for giving me prompt warning! . . . probably busy discussing art in the rapids . . .

Vince Caruso

Fri, Jul 19, 2013 : 3:11 p.m.

Clearly we need to handle rain water runoff (stormwater) in a more economic and environmentally friendly way. The city is doing more now with many Green Streets put in and many on the way. These are said to be less expensive then conventional streets. Other efforts are needed like working with business owners and institutions to install Green Roofs, porous parking lots and bio swales to deal with the water at the source. The U of M needs to do much more with near total unmitigated flows off the main campus with sewer overflows, flood hazard and pollution loading. When the city approached them to help with Green Streets efforts on campus they said no thanks. Sustainability Programs? With climate change these large rain storms with record rain falls are getting to be more common in Southern Michigan. Most of these alternative stormwater management technologies are even cheaper than conventional without the environmental saving added in! These technologies are getting much more in demand every day as are those who know to use them.

Jay Thomas

Fri, Jul 19, 2013 : 5:14 p.m.

U of M... always helpful.


Fri, Jul 19, 2013 : 3:09 p.m.

Humans can live 3 days without water, so what's the threat? LOL! And if the food production & transportation infrastructure breaks down: grocery-dependent populations would have up to 3 days supply of food to live on. No worries, right? LOL! Obviously, Mayor Hieftje was distracted by the greater emergency (in his opinion): joining Michael Bloomberg's Mayors Against Illegal Guns organization. Of course our very modest mayor didn't want to be credited with that bold move so it requires a search of MAIG's member list to find his name. Maybe he knows it was illegal guns that clogged our water treatment plant. So he was probably occupied with trying to shut down all the Illegal Guns R Us (®) shops... that don't exist. Whatever: sincere thanks to Stephen Ranzini for bringing (actually) related matters to our attention.


Fri, Jul 19, 2013 : 7:52 p.m.

Settle down Tru2Blue

Stephen Lange Ranzini

Fri, Jul 19, 2013 : 6:17 p.m.

@Tru2Blu76: Thanks!

Rork Kuick

Fri, Jul 19, 2013 : 2:28 p.m.

I admit having difficulty finding a link to previous reports that I saw, and I don't know why. I'm not that excited by 10000 gallons, during a storm like that, which might have sent the not-so-great water from Allen Creek into the river at 10000 gal/second (=1337 cfs). And that sacrilege happens with any big rain.


Fri, Jul 19, 2013 : 2:26 p.m.

Actually for all you cynical enviro types, the plant is required to contact communities immediately downstream during raw sewage discharges! And as for the volume discharged , it would be an equivalent of taking a leak in an Olympic sized swimming pool at the flow rates the river would have been experiencing! This was basically a non-event!

Basic Bob

Fri, Jul 19, 2013 : 4:04 p.m.

Can I use your pool? Only one day this summer. It should be good to use in a few days.

Rork Kuick

Fri, Jul 19, 2013 : 2:32 p.m.

Agreed, glad they acted quickly. 10000 gal was less than 1 seconds worth of the river's flow on a day like that.

Nicholas Urfe

Fri, Jul 19, 2013 : 1:58 p.m.

This was not well reported previously. I just clicked on the link above for articles with the wastewater treatment tag and no previous articles came up. This is something that should have been on a the front page for a number of days. It would have received a lot of comments. I re-iterate my assertion that it was not well reported.


Fri, Jul 19, 2013 : 1:33 p.m.

According to commented 751, this story was in fact previously reported right after the event. but it seems clear that most of us did not see this. I certainly didn't. Anyone who lives downstream of the plant should have known to stay clear of the river for a couple days after this disgusting event. I see kids swimming in the river almost every day. People like to wade out and fish. Dogs jump into the river in riverside park every day. Why was there no public health alert? I'd like to request to keep an alert ticker or sticky'd headline when disgusting and important events like this happen. Something we definitely deserve to know about.


Fri, Jul 19, 2013 : 1:08 p.m.

And they want to blame the E Coli on the feral cats!

Basic Bob

Fri, Jul 19, 2013 : 4:02 p.m.

That's a lot of goosepoop.


Fri, Jul 19, 2013 : 1 p.m.

Yes, Amy Biolchini, why the delay in publishing this story? Also, was the downstream water tested at the time as to whether or not an unsafe level of contaminants had been reached? What about now?


Fri, Jul 19, 2013 : 12:54 p.m.

Thank you Ann Arbor for this wonderful gift! - signed, The Folks and wildlife downriver Disgusting....

Dog Guy

Fri, Jul 19, 2013 : 12:44 p.m.

Ann Arbor has been exacting high and far-fetched water bill fees for decades to save up for rebuilding this plant. Now it will pay for it by a $120 million bond the fees and commissions foe which will go to a relative or friend. Other than in the Hurinal, where did the saved money go?

Steve Hendel

Sat, Jul 20, 2013 : 3:02 a.m.

And your proof that "relatives and friends"'will profit from bond issue fees is ....where?


Fri, Jul 19, 2013 : 12:37 p.m.

One can speculate that the delay in reporting the incident may mean that the waste water treatment plant could have handled the situation better and its staff wants to mute citizen criticism by providing a tardy announcement.

fed up 22

Sun, Sep 1, 2013 : 9:47 p.m.

Ross, it was reported to the MDEQ, Washtenaw County Department of Public health, and within 24 hours of the event. If you want to criticize, criticize, not the city employees.


Fri, Jul 19, 2013 : 1:29 p.m.

That's great, 751, but obviously none of us saw it. It should have been a major headline or continued health alert. Kids are swimming in the river downstream of the plant every day in the summer time, and I'm sure no one told them either. Gross.


Fri, Jul 19, 2013 : 12:50 p.m.

It was announced publicly immediately following the event. reported it, and Public Health/DEQ were notified within hours as per policy/law.

Linda Peck

Fri, Jul 19, 2013 : 12:23 p.m.

Perhaps there was a moral duty and responsibility to let the people of our communities know about this when it happened to avoid further contamination and possible disease?


Fri, Jul 19, 2013 : 1:40 p.m. you realize how many kayakers and canoeists are using that river everyday?


Fri, Jul 19, 2013 : 12:48 p.m.

There was no risk to the community, and it was reported previously.


Fri, Jul 19, 2013 : 12:16 p.m.

Stephen, Can I get a loan from your bank so that I can open several Perrier outlets in Ann Arbor?


Fri, Jul 19, 2013 : 12:01 p.m.

When you put 66 Mgd thru a system designed for 29 MGD something has to give! Sounds like the bar screens fouled up backing up thee incoming flow! Things happen very quickly at those kinds of flow rates. I'm sure plant operators did the best they could under extenuating circumstances! Mother Nature can be mean :-)

Nicholas Urfe

Fri, Jul 19, 2013 : 11:56 a.m.

"beginning about 5:20 p.m. June 27" So why the major delay in this reporting?

Nicholas Urfe

Fri, Jul 19, 2013 : 1:56 p.m.



Fri, Jul 19, 2013 : 12:38 p.m.

It was reported previously, immediately following the storm. You missed it.

Nicholas Urfe

Fri, Jul 19, 2013 : 11:52 a.m.

Get the convicted graffiti vandals to clean it with mops!

Alan Goldsmith

Fri, Jul 19, 2013 : 10:49 a.m.

Why did it take several weeks for this to be reported?


Fri, Jul 19, 2013 : 12:37 p.m.

Reported where? Here? There was brief coverage of it previously, following the storm aftermath. You must have missed that.


Fri, Jul 19, 2013 : 11:27 a.m.

Wish I could vote more than once for your question!

Stephen Lange Ranzini

Fri, Jul 19, 2013 : 10:39 a.m.

Here we are concerned with a minor transient event with no long term impact. Meanwhile the Pall Plume seeps inexorably underground with its toxic cancer causing payload towards Barton Pond. When it reaches there, ALL of our city's drinking eater will be poisoned. We have no alternative source of water. We've already lost one of our key water wells to this pollution. Our mayor and political leaders should be scrambling to do anything and everything to avert this disaster yet when I asked the Mayor recently what he thought could be done beyond the current strategy (to do nothing and wait and see if anything happens), he told the assembled group he was advised nothing more could be done. Cities die without access to clean water.

Stan Hyne

Sun, Jul 21, 2013 : 2:16 p.m.

As I recall, the contamination cleanup was held up by the city for years while Gelman tried to clean up the spill. Many of Gelmans proposals were stopped as not good enough, or would have had pipes running thru the wrong property etc.

Basic Bob

Fri, Jul 19, 2013 : 2:31 p.m.

The well that was shut down is not at the airport, it is behind Slauson Middle School. Groundwater flows in a predictable manner, and the consensus is that it will not contaminate the primary water source because it is upstream of the plume. The level of contamination is far higher at the WWTP than at Pall Gelman and the effects on humans is far better understood. This stuff will make people sick. Downstream, of course, so no one cares.


Fri, Jul 19, 2013 : 1:08 p.m.

Odd that they are laying a new major-sized h2o main along State & Ellsworth. They should have consulted slr first, perhaps.


Fri, Jul 19, 2013 : 1:01 p.m.

Thanks for the info Stephen. I guess they better start building that pipeline now!

Stephen Lange Ranzini

Fri, Jul 19, 2013 : 12:58 p.m.

@Arboriginal: The deep well at the airport was fouled by Dioxane from the Pall Plume and was shut. We are 100% reliant now on water drawn from the Huron River for our city's water supply.


Fri, Jul 19, 2013 : noon

Isn't there a deep well down by the airport? Charles Gelman's gift to the city is a giant tragedy that will peak in our lifetimes, but I imagine we will purchase our water from Detroit just like Hipsilanti.

Stephen Lange Ranzini

Fri, Jul 19, 2013 : 11:29 a.m.

To be clear by "Hieftje's Huironal" I am referring to the +$800,000 water sculpture in front of City Hall (a/k/a the Rog Mahal), and NOT the Huron River, which I love to use for recreation and don't want to see polluted by Dioxane.

Stephen Lange Ranzini

Fri, Jul 19, 2013 : 11:06 a.m.

ALL of our city's drinking water will be poisoned. Sigh, sorry for the typo! @Alan Goldsmith: Agreed! The river will be toxic and unsafe to use, but at least we'll have Hiefte's Huironal to wade in. :-o

Alan Goldsmith

Fri, Jul 19, 2013 : 10:51 a.m.

Stephen, apparently the Mayor and City have other more important priorities. Not surprised he said 'nothing more could be done'. But we sure have a nice fountain at the City Center building.


Fri, Jul 19, 2013 : 10:30 a.m.

Will the city get fined by the DNR? Where is the EPA who would fine a wild animal for crapping in the woods if it could. If this had been one of many private sewer system plants in the county people would demand it get shut down or taken over by a government agency. Cities can pollute pretty much without consequence.