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The Toilet Revolution: How Waste Can Transform Our World
Imagine sitting on a toilet perched high above the Alaskan tundra, contemplating a startling fact: each of us produces about 100 pounds of poop and 140 gallons of pee annually. For most of us, modern plumbing creates the illusion that our waste simply disappears-"flush and forget"-but this convenient fiction masks an uncomfortable truth. Our waste must go somewhere, and too often, it poisons people and ecosystems worldwide. Yet a revolution is brewing in how we think about toilets. From engineers like Emily Woods to entrepreneurs like Mwila Lwando, innovators are reimagining toilets not as mere waste receptacles but as opportunities for health monitoring, resource recovery, and environmental protection. This vision has gained unexpected celebrity endorsements, with Bill Gates investing $200 million in toilet innovation and even Matt Damon co-founding Water.org to address global sanitation. As climate change, resource scarcity, and inequality intensify, rethinking our relationship with toilets isn't just smart-it's essential for our collective survival.
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From Miracle to Crisis: The Toilet's Troubled Legacy
Our toilet systems, once revolutionary miracles, have stagnated while our societies have changed dramatically. Today's toilets are inadequate for modern challenges: growing cities overwhelming aging infrastructure, increasing pollution from waste, and squandering of valuable resources. Despite progress, toilets still fail to reach billions worldwide, with open sewage, "flying toilets" (poop-filled plastic bags), and inadequate facilities plaguing both developing nations and parts of America. The toilet has become a paradox - both civilization's savior and an exacerbator of inequality, disease, pollution, and resource waste.
In Sneek, Netherlands, I explored DeSaH's "New Sanitation" project - a radical reimagining of toilet systems. Instead of diluting waste with water, their vacuum toilets concentrate it; instead of centralized treatment, they process it locally; instead of consuming resources to treat waste, they extract resources from it. Their vacuum toilets use minimal water, sending concentrated waste to an anaerobic digester that produces biogas while microbes break down the waste. The system extracts nitrogen as gas, captures phosphorus as fertilizer, and processes gray water separately, even recovering heat from it.
Despite offering multiple benefits in a flexible system, this concept faces resistance worldwide. Visitors tour the facility but rarely implement similar systems at home, deterred by financial, regulatory and cultural barriers. People simply don't want to be early adopters of toilet technology - they just want reliable facilities.
Sneek succeeded because it embraced its "Water City" identity, had local company presence building trust, and possessed the characteristic Dutch resilience. This willingness to experiment represents the broader toilet revolution - a movement that's not just technological but cultural, potentially asking future users to separate waste streams, compost toilet waste, cook with septic gases, use recycled toilet paper products, monitor health through toilets, drink reclaimed water, and openly discuss toilets.
Before flushing away your waste, consider what exactly you're disposing of. According to Cranfield University researchers, people produce about four and a half ounces of poop daily (roughly three golf balls), though this varies considerably. Healthy poop is about 75% water, with the dry matter consisting of 25-50% bacteria - both dead and living microbes that help digest food and support immunity. Your gut contains trillions of microorganisms, making it one of Earth's most densely populated microbial habitats. The remainder includes undigested food (especially fiber), proteins, fats, cell debris, and compounds like calcium phosphate. Urine, the body's metabolic waste product, is 95% water with urea as its main component. Adults typically urinate eight times daily, producing about a third of a gallon.
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The Evolution of Sanitation: From Ancient Drains to Modern Challenges
Toilet systems evolved from primitive outdoor spots to increasingly sophisticated solutions. Early civilizations developed pipes, pits and pots - Mesopotamian settlements used clay pipes by the fourth millennium BCE, while simple pit latrines appeared by the third millennium BCE. Pakistan's Mohenjo-daro built the first comprehensive sewer drains, later improved by Romans with underground sewer networks.
The modern flush toilet emerged gradually - from Minoan-era Crete's water-rinsed drains to Sir John Harington's 1596 invention addressing privy stench. Alexander Cumming's 1775 patent added the crucial S-shaped pipe that prevented odors from rising, and by 1900, the ceramic wash-down closet had evolved into today's toilet.
As toilets proliferated in 19th century London, sewage overwhelmed the Thames, causing the "Great Stink" of 1858 and deadly cholera outbreaks. This crisis prompted comprehensive sewer systems, though pollution merely shifted downstream until the 1920s development of biological wastewater treatment using "activated sludge" - microbes that break down organic matter in aeration tanks.
Despite this "gold standard" system's century-long existence, it remains unavailable to billions. Hundreds of millions still practice open defecation, while 700 million use unsafe facilities like "hanging latrines." Another 2.2 billion rely on basic pit latrines that create "sludge bombs" when full, with waste often improperly dumped by unprotected workers.
Developing innovative toilet solutions requires entirely new scientific approaches. When environmental engineer Claire Furlong needed to test tiger worms' ability to consume fecal sludge, she had to collect "hippie shit" from volunteers in Wales who called themselves the "Poo Club," as London lacked pit latrines to sample from.
Toilet researchers face unique challenges - obtaining test materials, finding willing donors, and developing realistic simulants. Companies like Maximum Performance create synthetic feces from soybean paste and rice for testing, while researchers experiment with recipes containing everything from potato mash to miso paste.
New analytical tools help visualize sanitation problems. The "shit flow diagram" developed by Barbara Evans tracks where waste goes in communities, using green bars to show properly treated waste and alarming red bars for environmental contamination. In Cap-Haitien, Haiti, these diagrams revealed 99% of waste pollutes the environment, with only 1% properly treated.
Field testing presents additional challenges. Durban's Engineering Field Testing Platform builds community trust while testing prototypes in informal settlements. These tests reveal real-world issues - like when South African cleaning products' extra foam disrupted a high-tech treatment unit.
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The Toilet as Health Monitor: From Ancient Wisdom to Modern Technology
Silicon Valley entrepreneur Vik Kashyap's journey began with ulcerative colitis that conventional medicine couldn't cure. After attempting a fecal bacteria transplant without success, he turned to the hygiene hypothesis-the idea that modern cleanliness might contribute to autoimmune diseases. Desperate, he infected himself with whipworms sourced from Thailand, which miraculously put his condition into remission. This experience led him to obsessively track his health data and ultimately inspired a vision to transform toilets into health monitoring devices.
Throughout history, humans have developed cultural practices and beliefs around excrement driven by an instinctive disgust that transcends cultures. Ancient societies from Hebrew to Roman to Japanese all had specific rituals and beliefs surrounding defecation, though these weren't necessarily effective at preventing disease. Despite impressive Roman sewers and toilets, parasite infections remained common because they still contaminated water sources and fields with waste.
Fecal-borne diseases have shaped human history profoundly. The cholera outbreaks in London beginning in 1831 were particularly devastating - caused by the comma-shaped Vibrio cholerae bacteria that forces intestines to release rather than absorb water, causing such severe dehydration that death can occur within hours. While doctors initially believed in "miasmatic theory" (that illness came from bad air), physician John Snow traced an 1853 outbreak to a sewage-contaminated well on Broad Street, eventually helping establish the germ theory of disease. This understanding transformed toilets from decorated wooden encasements to simple white ceramic designs with fewer hiding places for germs, and accelerated sewerage development. Though modern toilets aren't perfect protection, they function essentially as "social distancing from poop" - a powerful defense against disease transmission.
Different cultures have developed distinct approaches to toilet use. The sit-versus-squat debate reveals physiological advantages to squatting, which straightens the intestinal tract for easier defecation. Studies show squatting takes less time and provides more satisfaction than sitting, with devices like the Squatty Potty now offering compromise solutions. Similarly, washing cultures (using water) and wiping cultures (using toilet paper) each find the other's practices unhygienic, though limited research suggests bidets may help with certain anal conditions while potentially causing irritation. Despite cultural differences in toilet design and cleaning methods, one universal habit emerges: most people, regardless of gender or nationality, admit to examining their stool, recognizing its diagnostic value.
In 1999, Indian livestock specialist Kamal Kar discovered that simply donating toilets to rural communities wasn't improving sanitation in Bangladesh. His Community-Led Total Sanitation (CLTS) method creates psychological shifts through community engagement rather than financial incentives. Facilitators take residents on "defecation area transect walks" and conduct demonstrations that trigger disgust - like touching a hair to feces then to water, asking if they'd drink it. This creates an "ignition moment" when people realize they're essentially consuming each other's waste. Despite widespread adoption, CLTS has faced criticism for potentially causing shame and stigmatization. Recent high-quality studies have shown surprisingly little improvement in childhood diarrhea or stunting from basic sanitation interventions, suggesting that more comprehensive approaches may be needed to truly improve health outcomes.
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Beyond Sewers: Alternative Waste Transport Systems
In Cap-Haitien, Haiti's sewer-less northern port city, torrential rains transform poor neighborhoods like Fort St. Michel into stagnant canals filled with floating debris. Here, nonprofit SOIL operates an unconventional sanitation service where workers in safety gear collect sealed pails of human waste from homes, navigating flooded streets with three-wheeled motorcycles fitted with flatbeds.
Since Roman times, sewers have represented both civilization's achievement and its dark underbelly. The Romans built the massive Cloaca Maxima in the sixth century BCE primarily to drain marshland rather than transport waste. These ancient sewers were imperfect - prone to silt buildup and rarely connected to private toilets due to concerns about backflow, stench, and pests.
Nearly fifteen hundred years later, London lawyer Edwin Chadwick envisioned comprehensive "arterial-venous" systems connecting water supply and waste removal. Engineer Joseph Bazalgette ultimately built London's groundbreaking 83-mile sewer network in the 1860s after the Great Stink, serving as a global model. Chicago tackled its sanitation crisis by physically raising the entire city to create gravity flow for sewers, and later reversed the Chicago River's flow to protect Lake Michigan from pollution. Despite massive municipal investments in sewers, they never became truly universal in America, with many post-WWII suburbs relying on septic systems that prove problematic on small lots.
The sewer boom has ended globally, with only 62 percent of urban dwellers worldwide having access to sewers-a percentage that remained flat between 2000 and 2017. In low-income countries, sewer coverage dropped from 24 to 17 percent during this period due to urban population growth. Many cities are now too dense and growing too quickly to install conventional underground sewers, creating an urgent need for alternatives.
In Frank Herbert's 1965 novel Dune, inhabitants of a desert planet wear "stillsuits" that reclaim all bodily waste moisture, returning it as drinkable water-an extreme vision of distributed wastewater treatment gaining traction in both poor and wealthy contexts.
Bill Gates has become the embodiment of the new toilet revolution since 2008. After witnessing poor sanitation firsthand, Gates rejected conventional sewers and treatment plants as too expensive and resource-intensive for many regions. Instead, he wondered if toilets could follow the path of computers-transforming from giant, expensive infrastructure into personal devices. The Gates Foundation has invested $200 million in "leapfrog" sanitation technologies that would allow poor communities to bypass traditional sewers altogether, similar to how mobile phones allowed them to skip landlines.
The foundation's most prominent initiative, the Reinvent the Toilet Challenge announced in 2011, funded university teams to develop off-grid toilets that treat waste on-site without piped water. The first winner from Caltech used electrochemical disinfection rather than microbes to clean wastewater. While Gates' involvement brought attention to sanitation issues, many development experts found his technological demands unrealistic and felt his approach might overshadow more practical solutions.
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The Hidden Value of Urine: From Ancient Resource to Modern Opportunity
I didn't appreciate "liquid gold" until I donated to Mothers for Mothers, a Dutch urine-collection organization seeking pregnancy hormone hCG for fertility drugs. This hormone, peaking 8-11 weeks after conception, has enabled millions of births through treatments like PREGNYL. Beyond fertility applications, urine holds other treasures - particularly phosphorus, an essential agricultural nutrient currently mined from phosphate rock in geopolitically unstable regions. With scientists warning of "Peak P," innovative pee-cycling projects are emerging worldwide: Malawian farmers directly applying aged urine, Vermont's Rich Earth Institute collecting thousands of gallons annually, and Switzerland's Vuna creating "Aurin," an approved plant fertilizer. Researchers are developing additional urine-based products: disinfectants, phone-charging electricity, and even bio-bricks formed through bacterial processes.
People worldwide use approximately 40 billion gallons of freshwater daily just to flush toilets-nearly six times Africa's entire daily water consumption. While low-flow toilets have improved since their problematic introduction in the 1990s, reducing water use from 3.5 gallons to under 1.6 gallons per flush, even these water-saving measures create problems for conventional sewer infrastructure.
In water-conscious Germany, reduced water usage has led to stagnating, stinking sewers in cities like Cologne and Berlin, requiring expensive odor-fighting measures and infrastructure upgrades. Similarly, San Francisco's rebate program for low-flow toilets resulted in hundreds of millions in sewer maintenance costs.
South Africa's colonial-era sewers face particular challenges. During Cape Town's 2018 water crisis, residents cut consumption by more than half through conservation measures like "letting yellow mellow," but this caused costly sewer blockages from insufficient water flow. Operators nearly implemented a citywide "royal flush" at predetermined times to move waste through the system. When rains finally came, the built-up sewer material overwhelmed treatment plants, demonstrating how water conservation can inadvertently break sewage infrastructure.
When Pete Buttigieg became mayor of South Bend, Indiana in 2012, he inherited a city plagued by combined-sewer overflows. These systems, which mix sewage and stormwater in the same pipes, regularly discharge untreated waste into waterways during heavy rainfall. About 40 million Americans in 860 communities rely on such systems, mostly in the Northeast and Great Lakes regions, resulting in billions of gallons of untreated sewage entering waterways annually.
Traditional solutions are prohibitively expensive for smaller cities like South Bend. Instead, Buttigieg's administration expanded on his predecessor's partnership with Notre Dame and Purdue University to develop a network of wireless sensors throughout the city's 600-mile wastewater system. These sensors monitor water levels every five minutes and control valves and gates to optimize flow. This "smart sewer" approach reduced South Bend's annual overflows from 1-2 billion gallons to under 500 million gallons with just a $6 million investment. As Buttigieg later said on the campaign trail, "I think about wastewater management as freedom. If a resident of our city doesn't have to give it a second thought, she's freer."
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Waste to Resource: The Circular Economy of Human Excrement
When Carl Pawlowski was growing up in 1970s Quincy, Massachusetts, his hometown was the "Flounder Capital of the World," attracting busloads of fishermen from as far as New Jersey. But this abundance masked a serious environmental crisis. Boston's failing wastewater treatment plants were dumping 350 million gallons of barely treated sewage daily into the harbor, creating a visible "brownish-greenish" scum film and destroying crucial seagrass meadows. The pollution became so notorious that after Quincy's city solicitor William Golden discovered he'd been jogging through human feces on a beach, the city sued the commonwealth. This lawsuit contributed to a national movement that made it illegal for utilities to dump sewage in waterways. Today, Pawlowski works as an environmental engineer overseeing the factory that transforms Boston's sewage sludge into "black gold" - fertilizer that powers crops, forests, and lawns across America.
In the 1980s, Joe Jenkins pioneered modern humanure composting on his remote Pennsylvania property, eventually publishing the widely translated "Humanure Handbook." His approach echoes Victorian-era innovations by Reverend Henry Moule, who patented "earth closets" in 1860 - wooden chairs with holes and buckets underneath, plus soil hoppers for covering waste. While these systems worked best in managed communities, they fell out of favor as flush toilets became standard. Yet composting toilets periodically resurface as environmental trends. German researcher Ralf Otterpohl developed "terra preta sanitation," inspired by ancient Amazonian soil-making techniques, where charcoal mix and lactobacilli bacteria transform feces into fertile soil through controlled decomposition. Other sustainable approaches include twin-pit latrines popularized throughout India by Bindeshwar Pathak's Sulabh organization, and the Arborloo, where filled toilet pits become planting sites for fruit trees.
Black soldier flies, once considered pests in 1930s Louisiana latrines, are now recognized as ideal biological waste processors. Unlike other flies, they don't eat as adults and therefore don't spread disease, while their larvae devour organic waste voraciously. Companies like AgriProtein have developed industrial-scale operations where billions of these flies process food waste. In Cape Town, their facility transforms larvae into protein powder for animal feed and oil for various applications, with the remaining waste serving as fertilizer. Researchers discovered these larvae eat collectively like a "self-pumping fountain," constantly cycling through feeding areas. While sister company BioCycle attempted to apply this technology to human waste in Durban, they encountered challenges with trash contamination and maintaining proper conditions for the larvae. Despite setbacks, companies like Kenya's Sanergy successfully use black soldier flies to process toilet waste from informal settlements into animal feed.
American engineer Emily Woods had a revelation in Kenya when locals asked if her solar fecal desiccator could be used for cooking instead. Realizing fuel was a more pressing concern than toilets, she co-founded Sanivation to produce "poop briquettes" that burn cleaner, last longer, and cost less than traditional charcoal.
Perhaps most promising is hydrothermal processing, refined over 40 years at Pacific Northwest National Laboratory. This technology pressure-cooks organic material in water just below its supercritical point, breaking down complex molecules in minutes rather than millions of years to produce bio-oil and methane. Genifuel Corporation is now implementing this technology with Metro Vancouver, processing sewage from 30,000 people into five barrels of oil daily while eliminating disposal challenges. If applied nationwide, this could meet 4% of U.S. jet fuel demand-or nearly 25% if combined with other wet wastes.
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The Toilet as Social Justice: Access, Equality, and Human Dignity
The American obsession with bathrooms reveals deep inequalities in toilet access. Americans now expect roughly one toilet per household member despite rarely needing simultaneous use, with bathroom renovations yielding $1.71 in home value for every dollar spent-three times more cost-effective than kitchen renovations.
Meanwhile, toilets function as tools of control and exclusion for vulnerable populations. Poultry workers wear diapers when denied bathroom breaks, gig workers struggle to find facilities while delivering, and the new "StandardToilet" intentionally tilts forward to discourage workers from sitting too long-making the restroom "another place where people impose the very capitalist idea that people should always be working."
Public toilets routinely fail marginalized people, lacking accommodations for activities like changing menstrual products, breastfeeding, or administering medications. Globally, a third of children lack basic sanitation at school. Even toilet labor reflects inequality: women more likely clean toilets at home while men dominate paid sanitation jobs, with just one in five water utility workers worldwide being women.
Italian artist Maurizio Cattelan's gold toilet "America" perfectly captures this inequality-a functioning 18-karat gold toilet installed at the Guggenheim where visitors waited hours to use it, described as "one-percent art for the ninety-nine percent." The piece was later stolen from Britain's Blenheim Palace, where it had been installed in Winston Churchill's former bathroom.
Menstruation remains deeply stigmatized despite affecting women for nearly seven years of their lifetime. Period poverty-the inability to afford menstrual products costing up to $120 annually-forces many to use unhygienic alternatives like newspapers or rags, miss school or work, or engage in risky behaviors. In rural Kenya, researchers found some fifteen-year-olds reported engaging in transactional sex to afford menstrual pads.
The "tampon tax" movement has successfully challenged the unfair taxation of menstrual products as non-essential items while items like dandruff shampoo and marshmallows enjoy tax exemptions. Kenya eliminated this tax in 2004, followed by Canada, India, Malaysia, and Australia. In the UK, student Laura Coryton's campaign gathered 320,000 signatures, leading to policy changes, while in the US, state-by-state efforts continue despite resistance from some lawmakers.
In 2012, the Gates Foundation approached a fragrance company with an unusual challenge: make toilets for poor communities smell significantly better. Firmenich, the world's largest privately owned fragrance company, took on the task of developing a new chemistry of "malodor control." Their scientists conducted a "world tour of toilet smell" across South Africa, Uganda, Kenya, and India, collecting samples from sixteen latrines. They identified about two hundred chemical constituents, narrowing them to five key molecules that recreate latrine stench. The team then developed "white fragrances" - odorless molecules that block smell receptors, combined with culturally appropriate pleasant scents. Testing showed these fragrances could increase toilet traffic up to 16% when combined with regular cleaning.
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Breaking the Taboo: Toward a Sustainable Toilet Future
In Surabaya, Indonesia, I encounter a "helicopter toilet" - a hole in a shed floor hovering over a rushing river. This unsafe sanitation method is common throughout Indonesia, where 25.5 million people practice open defecation. I meet Pak Koen, a successful "sanitation entrepreneur" who sells septic tanks to families like Ratna Ayuningtyas', who purchased one despite the expense for her daughter's health. Pak Koen has found meaning in this business, educating people while making money.
Like a modern Indonesian Thomas Crapper, Pak Koen is changing minds about sanitation. The real Crapper didn't invent the flush toilet but marketed it brilliantly in Victorian England, opening the first bathroom showroom and boldly displaying working toilets to overcome resistance to indoor toilets. Similarly, entrepreneurs like Pak Koen must change priorities and behaviors to advance toilet technology worldwide.
Our psychological relationship with toilets is complex, beginning with disgust - an emotional extension of our immune system that can overreact. Studies show disgusted people become more judgmental about unrelated moral issues, potentially making them less open to toilet alternatives. Research suggests connections between disgust sensitivity and authoritarian attitudes, with countries facing higher parasitic threats showing less openness to new ideas.
Our "flush and forget" tendency explains the sparse historical record of toilets. Studies of swearing reveal the universality of the poop taboo - fecal-related swear words are most common across 25 languages studied, with "shit" ranking among English's most frequent expletives.
This psychological avoidance has consequences for infrastructure. As Patrick Moriarty of IRC explains, we become blind to the complex systems and institutions that keep toilets working. We ignore sanitation issues until crises force our attention - whether it's recalled produce from fields without worker toilets, lack of public facilities for the incontinent, or sewage overflows during storms.
In Zambia's Bauleni slum, researchers from the London School of Hygiene & Tropical Medicine and the Centre for Infectious Disease Research applied Behavior Centred Design to improve sanitation without building new infrastructure. They discovered landlords were unaware tenants would pay higher rent for better toilets.
The team launched "The Bauleni Secret" - a stealth marketing campaign inviting landlords to secret meetings promising money-making tips. Through staged smartphone videos showing tenant conflicts over dirty toilets and potential renters rejecting properties with poor facilities, they demonstrated the financial benefits of toilet improvements.
In a randomized controlled trial involving over 1,000 landlords, those who participated were about 10 percentage points more likely to implement toilet improvements within six months. Some even built entirely new facilities. While this approach can't solve all sanitation problems - particularly sludge management requiring government support - researchers estimate willing tenant payments could increase flushing toilets from 15% to 58% of properties.
Unlike Thomas Crapper, Pak Koen sells toilets door-to-door throughout Surabaya, Indonesia's dense metropolis of 10 million. I shadow him through neighborhoods where he's spent years convincing residents to install proper septic systems.
Later, reflecting on his approach, Pak Koen shares his three-part sales philosophy: "First, I have to sell myself. I have to make people trust me. Second, I have to sell my company. And, third, I have to sell the product itself." There's no shortcut - it's just toilet by toilet by toilet.
As Indian author Arundhati Roy wrote during the COVID-19 pandemic, this crisis offers "a portal, a gateway between one world and the next." Just as the cholera pandemics led to our current toilet systems, today's crises could inspire new sanitation approaches that consider not just germs but food, water, energy, waste, nature, and humanity's shared future. The toilet may never inspire street protests, but a quieter revolution begins by talking openly about it - with sophistication, compassion, urgency, and hope.
