This article is part of the Design special section on water as a source of creativity.
In the sci-fi epic Sand Dune (books and movies alike), the people who inhabit the brutally harsh desert planet Arrakis wear clothes called dead suits that allow them to drink their own recycled bodily fluids.
These full-body survival suits, which look a bit like a technological version of an insect’s hard upper shell, absorb moisture from sweat and urine and filter impurities to make potable water. This water is stored in pockets and drawn up through a tube.
If this sounds like magical sci-fi thinking, the principle is similar to the sewage recycling systems already in use in some water-stressed areas of the world.
And in space. Last year, NASA announced that 98% of wastewater on the International Space Station is recovered with a new system that distills sweat, urine and other moisture in the cabin into clean drinking water.
Water infrastructure is largely taken for granted by those lucky enough to have flush toilets. But why does this technology persist? It makes sense to use vast amounts of fresh water to dispose of human waste, while, according to UNICEF, about 1.5 billion people in the world still lack basic sanitation? Along with throwing away a precious resource – in urban areas up to 30 percent of fresh water is used to flush toilets – we lose valuable nutrients needed for food production by not recovering them.
A number of recent initiatives, some more dreamy than others, propose to stop the flow of washed water. However, the challenges are enormous, given the cost of redesigning the infrastructure for human waste disposal and implementing it on a global scale.
I recently visited the Hamburg Water Cycle, in Germany, a pioneering wastewater reuse project in Hamburg’s new Jenfelder Au neighborhood. Instead of following the convention of piping water in from outside the city and returning waste to treatment plants, the new system separates wastewater into three streams for reuse locally.
Rainwater is collected for watering the gardens. “Grey water” from kitchen and bathroom sinks is treated for irrigation and flushing. And the “black water” from the vacuum toilets, a bit like those on airplanes, is piped to a local treatment plant where it’s turned into biogas. The system reduces water use by 30 percent and produces electricity for 225 households and heat for 70.
This project shows the ways to save water in new buildings, but how we go about retrofitting existing homes and commercial buildings is much more complex.
Dr. Upmanu Lall, its director Columbia Water Center at Columbia University, sees potential for alternative water systems in current attitudes toward other resources.
“It happened with the lighting. Most people have caught on to LED technologies and now the city is incentivizing phasing out natural gas for cooking and heating,” he said, “People like to update their homes every 10 to 15 years. how can we leverage this cycle in transitioning to new water technologies? If we could get 10 percent of the population updated at a time, in 10 years we would have transitioned.”
The next question is how to reuse human “waste”. Agriculture depends on industrial fertilizers containing phosphorus from mined phosphate rock. The mineral is quickly depleted and often extracted in hazardous areas, but phosphorus can also be recovered from urine.
P-BANK is a public demonstration toilet that invites people to donate their urine to recover phosphorus for reuse as garden fertilizer. According to P-BANK’s originators, the Bauhaus University Weimar in Germany, an average serving of urine (300 milliliters or about 10 fluid ounces) contains about 200 milligrams of phosphorus, enough to grow three or four carrots. — at least in theory. Currently, only Switzerland has approved its use Aurina liquid fertilizer produced from human urine.
In Kenya, circular waste management systems provided by Sanivation, a non-governmental organization, turn human waste into briquettes made from excrement mixed with organic matter, called super logs, which are used for fuel. Another NGO, Washking, in Ghana, where a lack of infrastructure means more people have smartphones than toilets, is installing low-cost toilets equipped with systems that break down organic materials to turn waste into compost.
Far from revolutionary, arguments about wet and dry drainage, the value of “waste” and the crisis of polluted waterways would have been familiar to sanitation reformers 150 years ago.
In the 19th century, according to Barbara Penner in her 2013 book “Toilet,Urine collection and waste water production were taken seriously.
“Government officials, health officials, scientists, and entrepreneurs dreamed of finding a way to use human manure,” he writes. “Most were driven by a genuine horror at how water closets were polluting rivers and wasting ‘God-given’ nutrients in human excrement. Most believed, however, that the reuse of sewage could be profitable – not an unreasonable idea at a time when there was still a functioning organic economy.’
Fast forward to the 1970s. Environmentalists as horrified as their predecessors by water pollution and excited by the possibility of recovering nutrients from human waste added water and energy conservation to the agenda as the environmental costs of water sanitation became obvious. Alternative living book sources such as the Whole Earth Catalog and Mother Earth News have published a number of off-grid systems for autonomous lifestyles.
But if circular systems didn’t take off then, what has changed today? Will the urgent needs of water scarcity and climate change overcome the barriers to water recycling being a key part of future drinking water strategies? Although sewage can be treated to make it safe to drink, in many places regulations prohibit this due to safety concerns. Another formidable obstacle is the reluctance of the public to drink recycled water. Or at least when people realize it’s being recycled.
Water-scarce Singapore already recycles all wastewater, including sewage, which is served to the public under the harmless NEWater brand. Other water technology marketers tackle the “yuck” factor head-on. Epic OneWater Brew is being marketed as greywater beer, a gimmick to promote the environmental company Epic Cleantec’recycling strategies. But that’s a mild challenge compared to a Berlin concoction of treated sewage, an initiative both to support Xylem Water Solution’s technology and to demonstrate to the public that water reuse is a sustainable way to protect rare resources.
There are indications that the boundary may be shifting.