Amid all of today’s talk about high-tech advances in water quality, purification and conservation, it’s humbling to stop and consider that one of the most important “technologies” is billions of years old and was “developed” without the help of a single human being.
I’m talking about dirt. As old as the earth itself. Responsible for about 30% of the world’s freshwater. The filtration system behind drinking water for more than half of the people living in the United States. Able to supply an estimated 79.6 billion gallons of fresh water per day in the U.S. for public/private supply, agricultural irrigation, factory uses and more.
If we think back not quite so far to when the bottled-water trend really began taking off, we find another irony, as well as homage for natural water filtration. Remember all the advertisements featuring people after their workouts and tennis matches? They all looked wonderful as they downed a bottle of clear, pristine spring water. I wonder how successful those ad campaigns would be if they revealed the truth: that a large percentage of that “fancy water” first traveled through thousands of feet of dirt before ending up in that plastic bottle!
What all this dirt talk boils down to is the filtration that happens as water from rain, melted snow, runoff, etc. makes its way through layers of soil. Each layer retains pollutants then lets the clean water continue its way down through other layers of filtration. Eventually water reaches an impermeable layer, and collects in a pool that can be “tapped” and pumped up for use. It may seem elementary, but I love this explanation of the process from Scientific American’s Science Buddies (plus it has a fun home experiment too).
While this process isn’t perfect – ground contaminates of various forms can compromise the quality of the water – it gives the water supply coming into filtration plants an amazing head start! Moreover, water companies take a lesson from Mother Nature in designing their own water treatment plants by using natural filters including sand, gravel and charcoal. So, as long as communities continue efforts to prevent groundwater contamination and take care not to deplete groundwater resources too quickly, it’s likely this “old as dirt” system of filtration will continue to stand the test of time.