Toilet-flushing accounts for as much as a third of all the water used in a home every day. We look at why, and how, toilet technology should be updated to help the planet
People change their mobile phones every year or two, so often indeed that retailers invented the word “upgrade” to gloss over the fact it usually means a new outlay of hard cash. Software and product designers work hard to satisfy this eager market with flash styling and new gimmicks.
Yet the basic design of the standard flushable Western toilet—the one most of us use every day—can be dated back to 1596 or, at least, the invention of the S-trap in 1775—reworked into the blockage-resistant U-bend by the great Thomas Crapper in 1880.
Whichever way you look at it, that’s well over a century of sitting down without really looking down and rethinking this essential everyday home appliance.
A global problem
The rich West might feel contented sitting on its well-wiped laurels, but huge volumes of water are being casually wasted. This puts pressure on supply when reservoir levels fall—as increasingly happens as a consequence of climate change. An average UK resident typically uses 135 litres per day, more than seven times the volume used by the Victorians who invented the modern loo. Toilet-flushing accounts for as much as a third of all the water used in a home every day. Some older toilets use 14 litres on a single flush.
Moreover, all that waste requires chemical treatment that’s costly and energy-consuming. Wet wipes and cotton buds cause blockages; when this happens, the contents of drains and toilets can end up in rivers and on beaches, killing fish and other wildlife. It costs £100 million a year to clear blockages. The use of biosolids—the polite name for human waste—as fertiliser is not widespread; we are flushing away a valuable product.
But in the developing world, where 2.3 billion people lack access to safe and affordable sanitation, the problem is far graver—and it's not simply a matter of upscaling what already exists. In most counties, the infrastructure isn’t there, nor the plentiful water.
The Bill and Melinda Gates Foundation has invested upwards of $200m in toilet research and development. During his 2015 Ted Talk, Bill Gates ruminated, “When I was a kid, the disaster we worried about most was a nuclear war. If anything kills over 10 million people in the next few decades, it’s likely to be a highly infectious virus rather than a war.”
Chillingly prophetic of the COVID-19 outbreak, the talk was titled “The next outbreak? We’re not ready.”
Dr Alison Parker, a lecturer in international water and sanitation at Cranfield Water Science Institute, is working to help the poorest communities be more ready.
In 2011 and again the following year, the Gates Foundation issued a challenge to researchers to “Reinvent the Toilet”. For the 2012 round, Parker joined forces with six colleagues from across disciplines and secured a grant of $810,000 to develop a prototype. Theirs was one of only four designs to win awards.
“I’d been working in low income sanitation for some time. The Gates grant allowed me to collaborate with experts in waste water treatment from the engineering and design fields.
“We needed to make a toilet that could deal with waste in a household in 24 hours. So not a compost toilet. The waste in those soon builds up and very quickly becomes a problem.”
As water becomes more scarce we might have to change our current ‘flush-and-forget’ way of life
The team came up with a groundbreaking Nano Membrane Toilet that separates solids and fluids using an Archimedes screw and burns the faeces by means of a gasifier. ‘
“It’s more about the membrane than the nano,” she says. “This allowed us to clear the waste out of waste water in as energy efficient way as possible.
“People shouldn’t think of it as a toilet but as a miniature sewage treatment plant—all the technology you’d have spread over acres had to be squeezed into a metre by metre unit. It’s not a step-change but a really radical change.”
The project is ongoing. Initial tests in South Africa have been met with success from local families; the toilet, for a household of ten, is designed to last for ten years.
Parker and her team are using the feedback to improve the prototype, which has already won several awards. She believes the ideas can be utilised elsewhere, including in wealthier countries.
“There are plenty of places that struggle to manage waste. Boats, trains and remote cabins are examples, and our design could be useful. Also, as water becomes more scarce we might have to change our current ‘flush-and-forget’ way of life.”
Professor M. Sohail Khan’s team at Loughborough University won a $400,000 (£340,000) award from the Gates Foundation for a prototype loo that converted human waste into “biological charcoal” to provide heat, minerals for soil conditioning, and water for flushing and hand-washing.
“The ‘business as usual’ approach to scaling up improved sanitation is not working in developing nations,” says Sohail.
“In many places, sanitation technologies are improvised or fail due to a lack of longer-term sustainability.
“There is a growing body of evidence that people want a toilet they can aspire to, one they can go out and buy and install once and for all, just as they would with other household appliances or mobile phones. In this regard, there is potential to introduce ‘leapfrogging’ technology in the sanitation sector.”
Loughborough’s innovative loo uses a process called continuous thermal hydrocarbonisation that kills all pathogens to create safe to handle, valuable material, and gets its power from the heat generated during processing. It doesn’t need a connection to electricity, a sewer or a continuous water supply.
“The toilet is designed to work in both single-family and multi-user contexts with daily running costs of just a few pence per person,” says Sohail. The prototype, which won a further $60,000 in a competition organised by the Gates Foundation, is now at product development stage.
Meanwhile in a bathroom near you….
It’s perhaps not surprising, given the scale of infrastructure, regulatory controls and public health concerns, that the UK and other developed nations haven’t changed their sanitation system significantly since the days of Crapper.
The bog-standard toilet works pretty well, after all. While water is not (yet) a luxury, there has been no call for a major upgrade. Nonetheless, manufacturers and designers in wealthier societies are turning their attention to the future of the loo.
South Korean designer Jang Wooseoks’s Eco Bath toilet, for instance, pipes grey water from a nearby sink. UK manufacturer Propelair’s latest design use 1.5 litres per flush rather than the nine litres of an ordinary toilet. Flushed water, it claims, accounts for 70-85 percent of commercial water use.
Other designers are tackling the issue of gender-neutral and dementia-friendly toilets. There is also—and some will consider this an attack on the royal rights of the throne-user—the issue of time. UK firm Standard Toilet claims “it is estimated that in the United Kingdom alone, extended employee breaks costs industry and commerce an estimated £4 billion per annum.” Its more “productive” tilted-seat design speeds things up and also helps combat haemorrhoids, apparently
Redesign is not all about functionality, however. In January, 2020, a loo scooped Wallpaper magazine’s award for “Life-Enhancer of the Year”. The “Save” toilet, created by Austrian firm EOOS, in collaboration with the Swiss Federal Institute of Aquatic Science and Technology and bathroom-maker Laufen—with, once again, funding from the Gates Foundation—traps urine to remove excessive toxins, thus protecting waterways from algal blooms, while siphoning off nutrients such as nitrogen, phosphorus and potassium in order to produce fertiliser for plants.
It’s gorgeous-looking, low tech—gravity does the flushing—and, according to EOOS, “revolutionizes the user interface”. That has to be the most 21st-century euphemism yet for powdering one’s nose.