I didn’t know that the WaterHub existed until this semester, which is a shame because it’s right in my backyard. From my dorm room at 15 Eagle Row, I can see the greenhouse and the mysterious metal trapdoors embedded in the grassy area near Peavine Creek Drive. But it wasn’t until my analytical chemistry lab trekked across campus, collection bottles and safety goggles in hand, that I learned how awesome the WaterHub really is.
One of the first things you see when you enter the WaterHub is a banana tree, happily flourishing among the greenery in the heat and humidity. Besides providing me with a bit of joy, the tree is working full-time for a greater cause. Its roots are the centerpiece of a hydroponic reactor beneath the greenhouse that harnesses the natural design of plants to provide efficient and stable water treatment.
As our tour guide explained to the class, the WaterHub recycles up to 400,000 gallons of water every day, meeting almost 40% of Emory’s total water needs. Don’t worry, though- our guide reassured us that repurposed sewage is not coming out of the water fountains. Instead, the recycled water heats and cools buildings and helps flush toilets in some of Emory’s dorms.
How does this Cinderella transformation occur? The treatment process begins with a series of moving bed bioreactors to settle out and digest the – um – solid components of sewage. These large tanks contain a floating plastic netting system where bacteria can settle and grow into compact communities called biofilms.
Different kinds of bacteria proliferate in different bioreactors, and the WaterHub puts each of them to work cleaning various components of the wastewater. Oxygen levels control the types of bacteria that flourish. One bioreactor is completely anaerobic, encouraging the growth of bacteria that can “denitrify” the water, reducing dangerous nitrates into harmless nitrogen gas. Other bioreactors have different oxygen conditions, and the microbes that grow there perform other functions.
The next step in the process also relies on nature; a vast network of plant roots dips down into a series of hydroponic reactors, providing maximum surface area for more junk-eating microbes to inhabit. Alongside the plants, there’s also an artificial system of textile webbing to provide additional filtration.
At this point in the treatment system, the water is pretty clear, and almost all contaminants have been removed. Still, the process isn’t over. Water passes through a clarifier and a filter, removing any remaining solids, nutrients, and color from the water. Finally, any straggling biological contaminants are zapped away with a combination of chlorine and ultraviolet (UV) light. Our class sampled this fully-repurposed water to test for various contents (Here is my blog post exploring this process in-depth!)
The WaterHub – once a mystery to me – is a brilliant marriage of sustainability, engineering, chemistry, and biology right on Peavine Creek Drive! Thanks to Dr. Weaver’s analytical chemistry lab course, I can now look out my dorm room window and appreciate the source of the water that heats the building on these cold winter nights – and the beautifully-evolved natural processes that keep it clean.
To learn more about the WaterHub, check out this link from Campus Services!