#113 Thanksgiving for Drinking Water
November 27, 2008
Walking through the South Fork Rivanna Water Treatment Plant brings a new appreciation for what it takes to turn river water into potable, safe drinking water.
This show originally aired on November 27, 2007 on “The Rivanna Rambler,” a weekly public affairs show airing every Thursday at 11:55 a.m. on WTJU 91.1 FM or wtju.net.
In late 1620, the God-fearing and intrepid band of Pilgrims aboard the Mayflower, first stepped on the outer shores of Cape Cod – close, but not quite there, in their search for a home and religious freedom in the New World. After an arduous 2-month voyage across the Atlantic, their stores of fresh water – and more importantly, the cider and beer on which most people relied for drink — were precariously low.
It took several forays down the sandy arm of the Cape to find rivers that spilled fresh water … and eventually, when they moved the Mayflower to what is now known as Plymouth Harbor, it was chosen as much for its protection from Cape Cod Bay as for the fresh water flowing in to it from the Jones River and a “very sweet brook” that flowed beside the landing rock, a brook that William Bradford wrote had as “good water as can be drunk.” He describe the water as “sweet,” perhaps an adjective hard for us to appreciate in our modern day, unless we remember that by the 1600s, many rivers – and city streets in the Old World – were already fouled by sewage and what we would today call gray-water from bathing and laundering — and were anything but sweet or safe to drink.
For our Thanksgiving gatherings today, perhaps the one thing on the table that costs little in money or time to prepare is the water that fills our drinking glasses. As a City resident, I get my water from the tap, with a simple turn of the wrist. I do pay a monthly bill for this service (so it is not exactly “free”). Ad because I recently had the privilege of touring the South Fork Rivanna Water Treatment Plant, I now know a little more of what goes in to making the water safe for me to drink and cook with.
Our tour, led by David Golladay, deputy manager water operations for the RWSA, starts outside in the chill bright air that has us all hugging ourselves for warmth as we walk the various stations of treatment. Raw water from the reservoir is pumped uphill to the treatment facility where it travels through a series of 100-foot long settling basins for processes that remove the organics and dirt that give it the dense green -brown color of raw. It’s a mini-lesson in chemistry, as we learn how aluminum sulfate and other compounds are added to encourage the unwanted particles to clump together like small gauzy patches of snow and settle to the bottom. As the water moves to other basins, long vacuum units remove what is now called sludge and send it down the hill to a dewatering facility that wrings out every last bit of moisture. Eventually, the partially treated water moves inside and under cover, where it is dosed a second time with lime to adjust the pH, and where small amounts of chlorine and fluoride are added for our health and inhibitors added to reduce corrosion from the various piping systems it will eventually travel. The treated water takes a final pass through filter basins made of crushed stone, sand, and coal, to capture any remaining impurities. The result is water that regularly exceeds the Federal safe drinking water standards.
All of these processes are overseen by one water treatment operator at the plant aided by modern electronics that provide closed circuit TV, automated and electronically controlled actuators for mixing and for analyzing water quality, pressure head, and flow through the various stages of treatment. This plant treats 12 million gallons a day and sends it into the vast distribution network that delivers the water, on demand, 24 –7 to homes and businesses like ours.
Sometimes I try to think of slogans for promoting water conservation – especially the potable water treated by treatment plants like the South Fork. One slogan might be, “If you had to carry it, how much would you use?” – possibly a useful reminder that the ease and efficiency with which potable water is delivered to ours taps disguises the amount of work that goes in to making it safe for us to drink. But maybe water conservation really starts with an understanding and an appreciation of what it takes to make water sweet as it travels from well or reservoir to our homes. And since appreciation is just one step removed from gratitude, this Thanksgiving, I will join in spirit with the Pilgrims and give thanks for water that is as “good as can be drunk.”