In recognition of Great Lakes and Fresh Water Week, I’m taking over the SEMCOG blog with a few posts on underground infrastructure – something I’m really passionate about. I’ve been working on water infrastructure systems since college, and I love talking about things like storm drains, manholes, and valves. While they might seem mundane, these are essential parts of how we manage water. It’s all One Water. Let’s keep it fresh and keep it flowing.
I wrote in my last post that several of Southeast Michigan’s stormwater systems are combined with sanitary sewer systems that collect what goes down the drain at our homes – dirty dish water, laundry residual, human waste, and toilet paper. These combined systems were built in the mid-1900s; at that time the population was smaller.
What happens after the flush?
Southeast Michigan’s municipalities and water resource providers do a great job managing underground infrastructure with technologies such as sewer cameras and pipe lining, but what if we put things down the toilet or drains that don’t belong there? Where does everything that is flushed go? When we drain our washer or take a shower, the water (and soap and dirt, etc.) goes down the piping in our homes and out underneath our yards to the sewer collection system. There it’s sent to a larger, regional collection system.
Let’s use my house as an example. I live in Ferndale. The wastewater line from my house goes under my front yard to the sewer system that runs under the road. That sewer, probably a 12-inch pipe, runs parallel with the road until it meets up with what’s called an interceptor sewer. These interceptor sewers are massive, think six to 12 FEET in diameter. That’s taller than my ceilings. These interceptors collect wastewater from communities all over the region and carry it all down to a water resource recovery facility.
This facility has a multi-step process for separating out the solids like toilet paper, cleaning the dirty water of all contaminants such as human waste, dish soap, the bleach you used to scrub the bath tub, your family’s dearly departed goldfish, the paint thinner you used to rinse your paint brushes, and anything else that makes its way down a drain. Once the water goes through all the steps to this thorough cleaning process, the water is discharged back out into a natural water body. In my example, it’s pushed back out into the Detroit River, which is where much of our drinking water in the region is pulled.
Whew, talk about a water cycle. This is not the process you learned about in earth science class back in junior high! Let’s walk it back a few steps to see where issues might arise. The facilities that collect and treat all of this wastewater were designed back in the mid-1900s along with the collection infrastructure. What was different back then? We did not have as much disposable junk. We especially did not have “flushable” wipes. Now what does it mean to be flushable? If your dead goldfish goes down the pipes, is it flushable? Sure! It went down. It was capable of being flushed. Are the treatment facilities prepared to clean dead gold fish out of the water? Probably not, but at least it’s an organic material!
How to keep it flowing
Let’s get gross for a second. What other things are “flushable,” but problematic for our wastewater treatment systems? Feminine hygiene products, condoms, grease from my pound-of-bacon breakfast sandwich, and flushable wipes can all physically be flushed down a sink or toilet, but treatment facilities are not prepared to clean these items out of our wastewater. These items don’t decompose over time like goldy would. They get caught in the treatment processes, ruining giant pumps, causing backups for accepting more wastewater, raising the cost of operations significantly.
If a person working at the facility has to stop what she’s doing to go rake the flushable wipes off of a screen once an hour, that raises costs for each community contributing wastewater to the system, which ultimately raises costs for us as consumers paying a water and sewer bill. Think about that the next time you try to flush a “flushable” item.
And by the way, those “flushable” items might not even make it out of your home’s plumbing system INTO the collection system. That bacon grease builds up so much that it reduces the size of your sewer pipe. Add those wipes to the mess, and the whole thing can clog completely. That could cause YOU thousands of dollars in personal plumbing and replacement fees. To help you save on personal costs to repair your own property and also lessen the maintenance required on our shared systems, I’ll put it in easy-to-understand terms. Let’s only flush the 3 Ps: Pee, Poop, (toilet) Paper.
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