'Basically your Brita filter;' Inside the Great Lakes Water Authority's massive water cleaning process

The water purification process happening inside the Great Lakes Water Authority is a bit like the operations inside a refrigerator - a massive refrigerator. 

The agency's chief operating officer of water and field services says "it's basically your Brita filter, but much much bigger."

And much more complicated. 

But the inner workings inside the regional water provider's facility in Detroit are vital to supplying Southeast Michigan with clean water. To do that, effective processes need to clean 70 million gallons a day.

"This is the raw water coming in at the source, it looks clean but it's not clean," Cheryl Porter said, looking over about a dozen water spouts each pouring water. "It's not until you get to the end where you actually have the tap water, this is your drinkable water"

The journey begins in the Detroit River, where water is pumped into an intake valve on Belle Isle and then moved to the Detroit location where a filter catches both small and large items. That includes sticks, twigs, fish, and even some shoes. 

It's first pre-treated with chemicals before getting stored in four large tanks, each capable of holding 80 million gallons. According to GLWA, the more effective the processes are to start, the better.

"The cleaner we get it upfront, the easier it is for us to ensure its quality leaving the plant," said Porter.  

Pre-treatment helps with taste and odor. After that, water is mixed with more chemicals that are churned by underwater fans. They look a lot like large ceiling fans. 

After that, clumps of dirt begin to form and accumulate. This process is called flocculation.

"The reason that is so important is that because we are clumping that dirt together, we want it to stay together," Porter said.

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As it gets heavier, the clumped dirt falls to the bottom of the bins. Meanwhile, water at the top is rushed to the next filtration spot. GLWA uses ozone, which is about 3,000 times more powerful than chlorine, to clean the water. It's a new process that involves technology that's still pretty new. 

Meanwhile, the dirt that is captured is moved into what looks like a giant washing machine, where the water is removed and the dirt is sent to a landfill. 

At this point, chemists take over the ‘polishing’ of the water, which requires constant maintenance and adjustment of chemicals to find the perfect level of purity needed for drinking.