It was on one of the few cloudy days we see here in Arizona, but several CAZACS members braved the overcast drizzle to take a behind-the-scenes look at how our drinking water is processed in the Valley. It was a fascinating tour!
We began where the canal meets the Deer Valley Water Treatment Plant, where the water is sourced for processing. Like many East-Coasters, I assumed that the drinking water in the City of Phoenix was from underground aquifers, and I guessed that the incoming water was probably consistent in composition. Clearly, I was wrong! 95% of the drinking water is sourced from surface run-off, which means that there could be a lot of variability in the water composition, and a lot of trace organic molecules (from plants, soil, or anything). Much of the water is kept in distant reservoirs, and water is released from these reservoirs into the canals depending how much water is needed, or is available. As a result, water treatment strategies must change daily (if not, by the hour!) depending on what’s in the incoming water. You can imagine how dynamic the water composition must be during monsoon season!
We also learned about the scale of the facility. Deer Valley can process up to 70 million gallons per day of raw water, and can reach as far as East Phoenix. Deer Valley is able to meet these demands because of their unique processing method, which is faster and uses less land-acreage than conventional methods (but you’ll need to take a tour for yourself to learn the details!).
For that matter, water treatment strategies also need to consider long-term goals, not just the day-to-day protocols. For example, one of our group asked about how the City of Phoenix Water Services Department considers population growth in the region. Our guide noted that even the Recession in 2008 dramatically changed their process strategy and water demands, as the regional populations responded to economic changes.
Particularly in an arid climate like Arizona, with future concerns about sufficient water as our world changes, water conservation is entangled with process plants like Deer Valley. In light of this, the City of Phoenix Water Services Department provides free resources and workshops to help Phoenicians conserve their water.
Of course, our group was most at-home in the testing labs. The water is tested at all points in the process pathway, to measure specific contaminants and to ensure that the water meets safe guidelines before it’s sent to the distribution network (where it’s further tested by another facility). Measuring these contaminants guides the process strategy, and also checks that the various filters and chemical treatments are working effectively. Our tour guide was also a chemist, so we did not shy away from technical questions about the instrumentation and methods!
Our tour guide also gave us some goodies before we departed for lunch, but not before alerting us to job openings for chemists who want to work in the Water Services Department for the City of Phoenix! Thank you for this valuable information!
In all, we all had a great time checking out the facility on this engaging and fascinating tour. Our guide was very knowledgeable and more than happy to answer all our nitty-gritty questions about flocculants and process chemistry. We learned a lot about what goes into clean water, a precious resource that should not be taken for granted.
Besides, it’s not often that you get to use a term like “flocculant” in regular conversation. Thank you to the Younger Chemists Committee for organizing this tour!