History and Design of the Bathroom Part 7: Putting a Price on Poop and Pee

This step is separating any solid waste from the water.

fotolinchen / Getty Images

I took some serious abuse in comments when I wrote Gates Foundation Throwing $42 Million Into The Toilet, questioning whether we needed a high-tech toilet solution. Commenters wrote: "This article is a disgrace and a sham." Niels Peter Flint, who I respect and have written about here, writes "The problems around human waste are ENORMOUS and here you just ridicule a very serious and honest approach to come with NEW & INNOVATIVE solutions."

But I was not ridiculing it. I was trying to make a point that high tech solutions are not always the most appropriate, and that economic and social systems have existed for centuries to deal with poop and pee, because the stuff had real economic value. I concluded by stating:

as we approach peak fertilizer and peak phosphorus, we should put a price on pee and on poop like we want to put on carbon. We can no longer afford to just flush the problem away.

Perhaps I was trying to mix too many concepts into one post.I did note the next day that "I was concerned that they were looking for a solution to a problem that was not technological but societal; that we need to relearn lessons from the past rather than looking for new toilets for the future."

For instance, one of the toilet designs being funded by the Gates Foundation, from the University of Toronto, "can dehydrate feces and smoulder them - like charcoal - to sanitize them within 24 hours. The powdery byproduct can then be used as an agricultural fertilizer. The toilet will also filter urine through a membrane, then disinfect it using ultraviolet radiation."

That sounds complicated, and probably consumes a lot of power. But in a Globe and Mail article, chemical engineer Yu-Ling Cheng of the U of T made an important point about toilets, that it is more than just about having a place to poop:

Dr. Cheng cites her visit to a village in India, where she noticed people continued to walk to a field to defecate, despite the presence of some basic toilets nearby. The reason for this was practical, she said. They could pick up firewood on their way back from the field.
Dr. Cheng said she's looking into offering mobile-phone minutes to people as an incentive for using one of her team's toilets - and a payment for their contribution toward the fertilizer it will produce.

Dr Cheng is reiterating the point that poop and urine have value. If, instead of treating it as waste, we monetize it like they did in China and Japan a hundred years ago, then it ceases to become something that we carelessly do in the fields.

Image credit Strategic Nine
Peak Fertilizer

Right now, the prices of the main components of fertilizer, nitrogen and phosphorus, are going through the roof. The reasons are simple; nitrogen fertilizers are made from fossil fuels, primarily natural gas.


While there is a temporary boom in natural gas thanks to hydraulic fracturing or fracing, (now commonly called fracking), gas is also replacing coal in power plants and may well replace gasoline in cars. Prior to the rapid expansion of fracing, it was assumed that we were pretty much at peak gas. All the fracing will push off the peak, but doesn't eliminate it. Read more in TreeHugger:
"Peak Fertilizer" To Make Manure A Valuable Commodity


Phosphate fertilizers are mined, and we are running out of them too. The Soils Association writes:

Worldwide 158 million tonnes of phosphate rock is mined every year, but the supply is finite. Recent analysis suggests that we may hit 'peak' phosphate as early as 2033, after which supplies will become increasingly scarce and more expensive.
This critical issue is missing from the global policy agenda. Without fertilisation from phosphorus it has been estimated that wheat yields could more then halve in coming decades, falling from nine tonnes a hectare to four tonnes.

More on peak phosphorus:
Fred Pearce On Peak Phosphorus: It's Time For Pee-Cycling
Is "Peak Fertilizer" Nearer Than We Think? New Report Fuels Concern

Yet we have seven billion people on this planet pooping out nitrogen-rich manure and peeing out phosphorus, often washing it away with drinking water. What kind of crazy system is this?

In Part 2 of this series, The History of the Bathroom: Awash In Water and Waste, I noted that some engineers advocated

"sewage farming," the practice of irrigating neighboring farms with municipal sewage. The second group, arguing that "running water purifies itself" (the more current slogan among sanitary engineers: "the solution to pollution is dilution"), argued for piping sewage into lakes, rivers, and oceans. In the United States, the engineers who argued for direct disposal into water had, by the turn of the 19th century, won this debate. By 1909, untold miles of rivers had been turned functionally into open sewers, and 25,000 miles of sewer pipes had been laid to take the sewage to those rivers."

It's time to admit we were wrong and fix it.

The fact is, if there was away of managing poop and pee, they would have real economic value. How much? Gene Logsdon, the author of Holy Sh*t: Managing Manure To Save Mankind tried to figure it out in the Atlantic. He indicates that fertilizer costs $80 per acre. The tiny farm wiki suggests a rate of 8.5 tons of manure per acre for an annual application. That puts an economic value of about 10 bucks per ton of manure. We know from our post The Flusher King: Testing Toilets that the average poop is 250 grams, or 1/4000 of a metric tonne, so on average, at current fertilizer prices, each poop has an economic value of two cents. Multiply that by a town or city and you are talking real money. And we haven't even got started on pee and phosphates.

Logsdon concludes:

Think of the excrement of 50 million people and 2.5 billion chickens helping to enrich soil rather than pollute water. Think of the food being produced without dependence on manufactured fertilizers or the need even for much fossil fuel. Think of all those people interacting with one another in their communities instead of running all over the world learning about nothing particular in any kind of deep, thoughtful way. Think of all those people feeling happy and important because they are involved in the meaningful work of feeding themselves and others, not overwhelmed by a paranoid fear that they are helpless before the dragons of a self-destructing economy. Think of something approaching an earthly paradise. If it gives you joy and contentment, who gives a poop what it's worth in money?

That may be overly romantic, we are still talking about poop. But here is how we might start:

clivus multrum toilet image
GreenBuild: I Have Seen the Future and it Flushes. Migrated Image / clivusmultrum.com

1. Bring Composting Toilets into our homes and offices

It has got to the point that composting toilets can be pretty much indistinguishable from conventional ones; this Clivus Multrum uses a little foam instead of water, but otherwise is a pretty normal throne. The difference is the back end; just as the toilet was an adaptation to a supply of running water, (see part 2) this is an adaptation to a clivus multrum composting system that has to be cleaned out every six months.

choi building

There is an entire office building in Vancouver that has been running off-pipe for 15 years. I wrote in my post on it:

It also shows that systems can be set up so that composting toilets are almost as care-free as conventional ones, if one uses an outside service to take it away. This is how it worked for centuries in China and Japan, where people came and removed the "night-soil"; with a modern composter like a Clivus Multrum it need only be serviced every six months.
It shows that we can design urban buildings that are off-grid but also off-pipe. The current system of installing huge concrete pipes to carry our crap into someone else's backyard may be convenient but isn't sustainable.

2. Separate and Collect Urine

First of all, it makes for better, more valuable poop. From Yellow is the New Green:

Research by Jac Wilsenach, now a civil engineer in South Africa, found that removing even half of the nutrient-rich urine enables the bacteria in the aeration tanks to munch all the nitrogen and phosphate matter in solid waste in a single day rather than the usual 30. Urine diversion also makes for richer sludge and produces more methane, which can be turned into gas or electricity, Mr. Wilsenach said. In short, separating urine turns a guzzler of energy into a net producer.

Secondly, it is valuable on its own. April notes how it can be easily turned into a valuable resource.. Warren quotes Cynthia Mitchell, an Associate Professor from the Institute for Sustainable Futures at the University of Technology in Sydney, in P is for Phosphorus (As Well As Human Urine):

"Urine will soon be too precious to flush down the loo," Professor Mitchell said. "Already in parts of Europe urine separating toilets are being introduced." Apparently all new homes in the local council of Tanum, in south-west Sweden, are required to have urine-separation toilets. That is the pee goes down one tube, and poo another. She goes onto say, "Sweden has set a national target that 60% of phosphorus in organic waste, including sewage, must be recycled. At least 30% of that goes to fertilise agricultural land." The Prof is calling on drought plagued Australia to realise "a revolution in sanitation, as dramatic and far-reaching as the construction of London's sewers during the Industrial Revolution."

Over a hundred years ago, Teddy Roosevelt said "civilized people ought to know how to dispose of the sewage in some other way than putting it into the drinking water." He is still right. It's time to get over our fear of poop, redesign our systems to separate and store poop and pee, put an economic value on it as fertilizer replacements and start putting it to work.