Who Wouldn’t Want a Bluetooth Toilet?


  • Toilets are a leading health innovation that prevent many infectious diseases and deaths, but the flush toilet has issues with accessibility and resource recovery.
  • Vermicomposting and container-based sanitation systems have demonstrated success in low-income areas because they are simple and require little existing infrastructure or water.
  • Pee-cycling is a compelling option in wealthier countries; these urine-diverting toilet can recover essential nutrients, allow energy recovery, and require less water.

Some flush, some don’t need sewers, some conserve and create resources, and some now come with Bluetooth. In addition to providing source material for countless bad jokes, World Toilet Day (November 19th) celebrates one of the singularly most important inventions in the history of human health. There is, in fact, no better predictor for life expectancy than access to sanitation. Toilets protect children, families and communities from deadly diarrheal diseases, cholera, dysentery, Polio, a suite of Neglected Tropical Diseases (NTDs), and malnutrition.

Alexa-voice recognition toilets may be new, but the first official flush has very old roots, invented in 1596 by the godson of Queen Elizabeth I, though not commonly used until the late 19th century when Thomas Crapper manufactured the first successful line. The toilet has not changed all that much from its earliest examples found in ancient Mesopotamia, Crete, and Rome, where the potential health benefits were often diminished by questionable hygiene behaviours such as using a communal sponge on a stick for wiping.

Unfortunately, some unsafe hygiene situations remain today. Two in five people lack access to basic handwashing facilities, even in the midst of a pandemic, and more than a quarter of the world’s population, and a third of the world’s schools do not have access to basic sanitation. Perhaps even more unimaginable, 21 per cent of healthcare facilities in Least Developed Countries have no sanitation services, meaning 1.5 billion people must rely on healthcare facilities without toilet facilities. There are multiple reasons — from funding and maintenance to prioritization. One of the reasons is also the flush. Flush toilets require extensive and expensive infrastructure and lots of water, which is not accessible for many in lower-resourced countries. In the U.S., toilets are the largest consumer of water inside residences. These toilets also limit resource recovery (such as fertilizers). These drawbacks make for some pretty innovative ideas for providing the remaining quarter of the world with basic sanitation. 

Caltech won a “reinventing the toilet challenge” sponsored by the Bill and Melinda Gates Foundation with a solar-powered toilet that breaks down water and human waste into fertilizer and hydrogen. Others have opted for simpler designs to avoid a quick descent into disrepair. One is the Tiger Toilet. These latrines use tiger worms to strip nearly all the pathogens from human waste, drastically reducing its volume, and converting it to compost. The worms also prevent odour and flies. The Tiger Toilet, and other vermicomposting toilets, have been successfully used in rural, peri-urban, urban, and displacement camp contexts. 

Digging latrines does not work everywhere, either. There may not be enough space to dig, excavation may be too expensive, and in areas with a high water table, latrines can lead to contamination. Container-based sanitation has emerged as a promising alternative in urban areas. Urine and faeces are separated, collected by the service provider, and composted by organizations such as SOIL. In some cases, faeces is turned into briquettes that burn cleaner than charcoal.

Diagram of a container-based toilet with separate containers for urine and faeces.

There are proposed alternatives in loo (sorry) of the flush toilet in high-income countries, too. One alternative recognizes that we flush away clean drinking water as well as precious nutrients found in urine. A solution, and an area of my research known as pee-cycling (yes, a riff on recycling), has a wide range of benefits.

Pee-cycling diverts nitrogen- and phosphorus-rich urine and recovers these nutrients as a fertilizer, instead of mixing it with other sewage. This stops these nutrients from causing algae blooms when not removed from wastewater, and reduces the large amounts of energy and chemicals needed to remove and dispose of them when we do. Having a renewable source of fertilizer avoids the need for conventional nitrogen fertilizers, which release 3% of the world’s carbon emissions; and it protects our supply of phosphate rock, which is essential for our food supply, nonrenewable, and could run out. The separated solid waste can provide electricity and heat to the wastewater treatment plant, the grid, and can even power vehicles. The United Nations states (in a more diplomatic manner) that poop could power 138 million households. Urine-diverting toilets also use much less water than typical flush toilets.

NoMix urine-diverting toilet.

Whether it’s a waste-eating worm or putting our pee to good use, on-going innovations need to be encouraged and supported until every person has the safety and dignity of a toilet. As we commend the commode, this ancient and remarkable invention, let’s not neglect those who cannot yet celebrate.


Stephen Hilton, MS & MSE, researched how the environmental impacts of #peecycling compare to traditional fertilizer production at the University of Michigan, and is a technical research assistant at Global Water 2020.

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