You say EW, I say YUM
Let’s talk about drinking poopwater! One of the biggest hurdles with implementing a recycled water system isn’t the high-end technology or the stringent regulations… Judging by your face as you read the words “drinking poopwater”, you know exactly what the hurdle is. It’s the public reaction. The super official term we call it in the industry: the ick-factor. It’s understandable that people don’t like the concept of drinking water that has been through someone else’s body. But it’s totally safe! Plus, if it’s good enough for astronauts, it’s good enough for me.
In fact, it can be cleaner than other drinking water sources because it’s gone through such rigorous treatment for chemical and biological contaminants. It’s certainly better than water found in rivers (which are exposed to all sorts of natural, surface hazards…like rainwater runoff carrying hydrocarbons from your cars). And let’s be honest: some of that river water was treated wastewater just upstream…
Oh, the glorious water cycle.
Throwback to 4th grade science class.
How does it work?
The treatment technology uses microfiltration (for bacteria and large organisms) and reverse osmosis (for dissolved materials and smaller organisms) to filter out particles. Then it may undergo advanced oxidation (ultraviolet light) to destroy low concentrations of potentially toxic compounds. That’s three separate barriers against contamination. I like this little schematic to help me visualize the size of these microscopic particles. And check out the schematics for how microfiltration and RO work (filters and fun. basically).
Toilet to tap
In the industry, we use many terms to describe treatment of wastewater to better-than-drinking-water standards. Reuse, recycled, reclaimed.
DPR (direct potable reuse) is the process of taking wastewater (municipal, industrial, etc.), treating it, and integrating it straight into a city’s water supply distribution system. IPR (indirect potable reuse) is wastewater that has been treated, then piped into a lake before being extracted and put into distribution. The only difference between the two is that in IPR there is an environmental buffer; in DPR there is an engineered treatment to take the place of the buffer.
In both cases it may still be treated again in the city’s conventional water treatment plant. If DPR or IPR is used to augment other limited sources such as groundwater or surface water, the recycled water will then be blended into the other supplies. This creates a more homogeneous product.
Water is a Sovereign Risk
In reflection (see what I did there?) of World Water Day this week, I found a video clip (link here) describing how reuse is a staple technology for water conservation in Singapore. With the limited available supply from water catchments (lakes, etc.), it’s no wonder the government is extremely concerned with using a robust and diversified supply of water. This includes importing water, using reclaimed water, or desalination of brackish water (sea water).
Reading: Breaking Smith’s Quarter Horse by Paul St. Pierre. It’s a Canadian western with loveable characters, real relationships, and a hilarious writing style. I learned just a little bit more about cowboy culture…and learned that there’s so much more I don’t know. Plot is so engaging I finished it on one long plane ride. Highly recommend.
By the way, I LOVED The Fifth Season. Head over to my goodreads to check out my review of it.
Working: Using GAMs (groundwater availability models) in Groundwater Vistas to export aquifer parameters into GIS shapefiles. The end product will be some really good information about what capacity of groundwater we can feasibly pull from the aquifer. And some gorgeous maps. I love using the creative parts of my brain to do engineering! All synapses firing! (That’s not how it works, does it?)
Listening: Relax Lite app. Some weeks are just worse than others.