Which is more valuable: diamonds or water? It’s clear to me. Water is the perfect product. It is endlessly useful, cheap, simple, ubiquitous, and beautiful. Water is essential to all forms of life and is used in every industry, not to mention its calming presence. As our species continues to shape the planet I find it critically important that we take great pains to conserve the purity of this critical chemical. This is why, when my friend George McGraw of digdeepwater.org invited me to take the 4 Liter challenge I jumped at the chance.
The rules are simple. Do not use more than 4 liters of water per day. I also decided to track ‘virtual’ water usage. That is, be mindful of the water used to produce a good that is used, in addition to water used directly. Given that a single toilet flush takes over 6L of water, and the cotton in a pair of jeans takes about 7000L to grow, some changes to my life were clearly in order.
I awake the morning of the challenge and throw off my cotton sheets with disgust. From this moment on every drop counts. I brush my teeth without water and put on dry deodorant. Relieving myself in the toilet is not an option. For a moment I consider following Clinton’s advice: “if it’s yellow let it mellow”, but decide to go full Bukowski instead: “sometimes you just have to piss in the sink”. Could we engineer more efficient kidneys?
For number two I had to plan in advance. Inadequate sanitation is an enormous quality of life problem globally. The most popular toilet in the world is no toilet at all as 4 in 10 people in the world defecate in the open. Flush toilets use enormous quantities of water so I needed a way to make it unnecessary.
Feces are almost entirely deceased gut bacteria and water. I massacred my gut bacteria the day before by consuming a DIY Soylent version with no fiber and taking 500mg of Rifaximin, an antibiotic with poor bioavailability, meaning it stays in your gut and kills bacteria. Soylent’s microbiome consultant advised that this is a terrible idea so I do not recommend it. However, it worked. Throughout the challenge I did not defecate.
In lieu of showering I sprayed myself with AOBiome’s custom skin bacteria blend. Body odor is caused by the emissions of proliferating skin bacteria, as unique as a fingerprint. The Nitrosomonas eutropha taking over my skin now metabolizes ammonia into odorless nitrite and nitric oxide. Success! I wish I had a strain that excreted lipases, as my hair was still greasy.
Direct water usage: 0L
Virtual water usage: 0L
My standard outfit is mostly cotton, which takes 20,000L of water per kg so I had to improvise. I did some research and settled on Nomex, a meta-aramid invented by DuPont in the 1960’s. Nomex is a fantastic material used in applications as diverse as circuit boards, loudspeakers, and clothing. Made via condensation from m-phenylenediamine and isophthaloyl chloride, its production uses no water. I found a Nomex flight suit on Alibaba and added a “Soylent” patch. I love it. It’s cheap, simple, comfortable, and fireproof, just in case. I also did no laundry of course, which would have used 170L.
Direct water usage: 0L
Virtual water usage: 0L
There are some species that never drink water. They obtain it from the food they eat, or synthesize it biochemically. Humans only synthesize about 10% of their water needs which means I’ll need to drink some. I also need food, the production and distribution of which is the single largest burden on the water system by a mile. Agriculture constitutes 80-90% of the water used in the United States. A mere kg of red meat takes 15,415L of water to produce. I was a little crestfallen to learn that a single cheeseburger can outweigh using a high efficiency toilet for a year.
To avoid this issue I consumed nothing but Soylent throughout the challenge. Soylent uses no meat or dairy and only 1.6L of water. To avoid dishes and their subsequent water usage I poured my Soylent one meal at a time in to a polystyrene cup, which takes less than 1L of water to make. Soylent does not contain enough water in itself so I begrudgingly drank an additional 400ml of tap water.
If there’s anything as amazing as water it’s petroleum. My clothing and dishes take less water to make than they do to clean.
Dying to know the virtual water footprint of Soylent, we contracted an analyst at a Chicago think tank to run a study on the product. The complicated formula and numerous sources, as well as proprietary manufacturing and process information made this difficult and a bit imprecise. However, there was enough published data to end up with a conservative estimate. Rice protein was the biggest issue, given that rice is relatively water intensive to grow and is only about 10% protein by mass. Our rice processor claims they have a 0 carbon footprint and reclaim much of the water used but I couldn’t get many specifics. Not accounting for this we still ended up at 2030L per day of Soylent, which is about 50% of the virtual water footprint of the standard american diet (SAD), 4000L. Not bad. I bet we could lower it though.
Complete analysis here (criticism encouraged): https://s3.amazonaws.com/robrhinehart.com/soylent-water-footprint.xlsx
Direct water usage: 2L
Virtual water usage: 2031L
Direct water usage: 1135L
Virtual water usage: 7570L
Water is the most popular beverage in the world, and still 20% of us are living without enough even to drink. Our foods, our bodies, and our planet are mostly water, and yet, we are spoiling and wasting what the cosmos has made at an unsustainable rate. I don’t expect anyone to live as I did during the challenge. Even I missed coffee and a hot shower. However, I do think it is important to be mindful of the network effects of one’s lifestyle. With water, as with most things, it is better to do more with less.
It is possible that a substantial amount of earth’s water was synthesized by purple sulfur bacteria in the photosynthetic reaction
This means we could manufacture water out of sunlight, CO2 and flatulence. What if we scaled this up?