It is a resource we tap dozens of times each day. We use it to drink, cook, wash, and nourish. But how many of us stop to consider where our water goes when we're done with it?
"Whenever someone flushes their toilet, takes a shower, or puts something down their drain, it comes down a series of pipes and ends up at one of our eight waste water treatment plants," Rebecca Flood of the Metropolitan Council's Environmental Services division said.
The council is responsible for collecting and cleaning water from all across the metro area. Its St. Paul plant is one of the nation's largest, handling an average of 215 million gallons of effluent each day.
Water and sewage from at least 61 communities and 800 industries travels through a network of sewer pipes hundreds of miles long arriving on the banks of the Mississippi for a serious scrubbing. "We essentially clean the water once it gets here," Flood explained.
The first step is separating large solids from the dirty, or brown, water. The solids are strained out, carried off on a conveyer belt, then trucked away for incineration. The remaining water flows to another tank, where gravity strips it of sand and grit. The next step sees the gradually-clearing wastewater pumped full of oxygen to stimulate bugs and bacteria that devour pollutants. After that, the water is pushed through a chlorination channel to kill any remaining germs. The final step is to de-chlorinate the water, before it is released into the Mississippi River.
"I think our waste water plants do an exceptional job at treating waste water," Flood said. While waste water plants remove nearly 99 percent of contaminants, there are things we call can do to minimize water pollution on the front end of the equation, so it can be even more clean when it re-enters the watershed.
"It's important to think about what goes down the drain, because what goes down the drain affects us," Mississippi Watershed Commissioner Scott Vreeland said. "It comes back to us. It's all going to a river, or going to a lake or a pond." One example of how consumers can help is phosphorus.
Vreeland suggests using laundry, kitchen, and dishwasher soaps that are free of phosphorus - an element that promotes algae and plant growth. Too much plant growth can lead to fish kills. Even the food you grind up in your garbage disposal can be a major drain on water quality. "With a disposal unit, 17 percent of your kitchen garbage is going down the drain. If you're putting it in there, then it's going to a treatment center, but it's kind of clogging up the treatment center, and it makes it more difficult to get a clean river," Vreeland said.
Where we were once encouraged to flush old medications down the drain, the practice is now considered a major no-no. "Right now we're taking a lot of medications (as a society)," Commissioner Vreeland said. "The hormones are something we've noticed. Fish are changing sex, and weird things are happening in the water because of things we're putting down the drain."
Related: KARE 11 Investigates: What's in the Water?
There's another kind of used water that makes its way back to Minnesota rivers and lakes without being treated. Stormwater - rain or snowmelt that runs off land and pavement and into storm sewers - goes directly into rivers like the Mississippi, the Minnesota, and the St. Croix.
During an intense storm event, the water that storms St. Paul's old Troutbrook tunnel can surge to nine feet high. To reduce urban runoff, and the amount of unfiltered water pouring into our natural environment, environmental scientists are developing new technology like the porous pavement parking lot at the Ramsey Washington Watershed Headquarters.
It allows storm water to filter down through the grounds natural aquifer, instead of rushing to sewer grate with a bunch of urban pollutants along for the ride. It's easy to take water for granted, with Minnesota holding so much of it. But it's the quality and health of that water that measures how we live our lives.
We can do better, and we should, as future generations depend on it.
(Copyright 2007 by KARE. All Rights Reserved.)