11 Oct 2012

How No-Flush Toilets Can Help Make a Healthier World

Inadequate sewage systems and the lack of toilets in much of the developing world have created a major public health and environmental crisis. Now various innovators are promoting new kinds of toilets and technologies that use little or no water and recycle the waste.
By cheryl colopy

My apartment in Kathmandu, where I lived for five years, had a toilet that looked very much like the one in my house in California. Nicer even; it was pastel porcelain and had dual flush.

But although flush toilets in Nepal and the rest of South Asia may work quite well, sewer systems have not kept pace. My toilet and all the others in my Kathmandu neighborhood were connected to pipes that carried the contents of toilets away from our residences and straight into a small river a half-mile away. Stray dogs lapped the water and children played nearby.

The rivers of the Indian subcontinent flow clean and clear from the Himalaya, then become little more than sewers as they run through major cities in the plains. New Delhi’s Yamuna River receives roughly half of the largely untreated sewage of a metropolis of 17 million. The Ganges, the holiest of Hindu rivers, is fouled by raw sewage from tens of millions of people as it flows 1,500 miles from the western Himalaya to the Bay of Bengal.

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California Institute of Technology Toilet

Bill & Melinda Gates Foundation
A solar-powered toilet designed at the California Institute of Technology recently won a prize from the Bill & Melinda Gates Foundation.
A movement is gaining momentum to do something about this major environmental and public health problem in South Asia and the developing world. The solution, many experts say, is not to invest in western-style flush toilets and centralized sewage systems but rather to develop toilets and decentralized waste-treatment technologies that use far less water. The latest development in this field is the decision by the Bill & Melinda Gates Foundation to invest $40 million in prize money and financial support to groups working on new toilet technology.

The goal of the Gates Foundation and other international and South Asian initiatives is to construct prototypes of inexpensive toilets that use little or no water and minimal energy. The new toilets must convert human waste into useful (or at least benign) components without using septic systems. Most important, they must protect water sources — rivers, streams, and groundwater — from the water-borne diseases so endemic in the developing world.

The stakes are enormous. Water-borne diseases such as typhoid, hepatitis, amoebic dysentery, and garden-variety diarrhea kill 1.5 million people each year, most of them children. Globally, 1.2 billion people — approximately 600 million of them in India — are still defecating in the open, according to a United Nations report. Earlier this month, India’s Rural Development Minister Jairam Ramesh stirred controversy when he bemoaned the abundance of temples in India compared to its lack of toilets.

Governments and international donors in South Asia continue to pursue solutions that follow the methods employed during the last 150 years in the West, where sewage is piped long distances to big treatment plants that typically use a lot of energy and require large amounts of water. But these expensive systems are completely inappropriate for the water-stressed megacities of South Asia, and they are becoming even more untenable as the population grows, water resources are depleted, and global warming threatens to exacerbate water shortages in some regions.

Ironically, sewage pollution of South Asia’s rivers has worsened as increased affluence and population growth have led to wider use of flush toilets. Sewage systems have failed for numerous reasons. Pipes get clogged; diversion canals sometimes do not work, or there’s not enough electricity to run treatment plants; and frequently sewage systems simply
One newly designed toilet uses solar power to transform human waste into fertilizer and hydrogen.
don’t get built or are built to the wrong specifications, despite a large investment of funds by governments — particularly in India — and foreign organizations.

Toilets can use up to seven liters of water per flush, thus creating large amounts of sewage that often pours directly into waterways. As a young Indian architect, Sheel Raj Shetty, who works on solutions to the toilet conundrum, points out: “Eighty to 90 percent of fecal matter is water. If you remove the water, what’s left could be contained in a small matchbox. What we say is, ‘Don’t flush your [waste]. Don’t put water in.’”

The new toilet technologies aim to heed this advice, while also striving to produce hygenic toilets that are dramatically different from an old-fashioned outhouse. In August, the Gates Foundation awarded its first prize to environmental science professor Michael R. Hoffmann of the California Institute of Technology, whose team devised a toilet that uses solar power to transform human waste into fertilizer and hydrogen. The hydrogen from the electrochemical reaction can be used in hydrogen fuel cells as energy, and the treated water can be reused to irrigate fields.

Hoffman says the technology behind his prize-winning solar-powered toilet had been sitting on the shelf since he demonstrated it to NASA in the early 1990s for use on the International Space Station.

The second-place winner designed a toilet that transforms human waste into biological charcoal, minerals, and clean water. The third-place winner devised a method to treat urine and feces separately, using sand to filter urine; feces dries inside the toilet and can be used as fertilizer.

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Eram Scientific Solutions E-Toilet

Eram Scientific Solutions
The “e-toilet” being developed by Eram Scientific Solutions employs an anaerobic process to digest waste.
In South Asia, forward-thinking entrepreneurs and engineers have begun important pilot projects, and early adopters are already combining ecological toilet technology in their homes with rainwater harvesting, dual pipes, and composting. Eram Scientific Solutions, based in the Indian state of Kerala, has received a grant in the second round of the Gates Foundation toilet initiative to continue work on its e-toilet, which employs an anaerobic process to digest waste. The e-toilet is a self-contained unit inside a brightly colored booth that can be situated on a city street. It has already been tested at 300 sites in Kerala, a state with one of India’s best-educated populaces.

Eram Scientific Solutions plans to sell the device in the developing world, but the coin-operated, self-sanitizing booth would be appropriate in the developed world, too. The e-toilet would be connected to an electronic system for monitoring, which would also allow potential users to locate toilets on city streets. Eram also is working on decentralized sewage technology that could be used for up to 25 families.

Lack of technology, however, may not be the chief cause of failed sanitation in South Asia and elsewhere. People who have long been working to promote sanitation in the region point out that while technology is good, too much focus on it alone can actually be detrimental. An array of other issues matter just as much: personal habits, family priorities, local customs— and above all whether communities are receptive to change. And so far, says Eklavya Prasad, efforts to propagate toilet technologies tend not to take all this into account.

Prasad, who directs Megh Pyne Abhiyan — a coalition of grassroots groups working on sanitation in the Indian state of Bihar — notes that governments often want a one-size-fits-all solution. If the device is right for the locale and social workers clearly explain to people how to use and maintain it, things generally go well, as they have in parts of Bihar. If not,
People in some parts of the world still need to be convinced that toilets are necessary.
the toilet may sit unused while people continue to defecate in the open.

A very simple and successful technology called the sulabh toilet has been propagated for several decades by Stockholm Water Prize winner Bindeshwar Pathak. But even this basic and inexpensive toilet has required some marketing to become popular in India. Pathak’s work began with a crusade in Bihar to rescue a caste condemned to manually cleaning dry toilets for higher castes. His solution, still widely used throughout the developing world, consists of two large pits in the ground with a squat toilet — the type preferred in Asia — in between.

The sulabh toilet requires only a liter or so of water per manual “flush.” A family or neighborhood can use the toilet until one pit is filled, then switch to the other one. In a couple of years, when the second pit is full, the contents of the first have decomposed, become sanitary, and can be removed for use as fertilizer. In cities, large sulabh facilities are connected to biogas systems so that the waste is processed into energy.

More recent solutions for rural India include versions that do not overflow during floods and urine-diverting ones, which separate out phosphate-rich urine so it can be used as fertilizer. Dutch water and sanitation specialist Marijn Zandee has worked with UN Habitat in Nepal on urine-diverting toilets. He says this type of toilet may become more important as mined rock sources of the crucial fertilizer phosphate continue to diminish. Regarding the Gates initiative, Zandee cautions that “having a cool new technology may help,” but many people still need to be convinced that toilets are necessary. In addition, he says, sanitation laws and enforcement mechanisms must be created, along with a supply chain and maintenance services.


Beyond Big Dams: Turning to
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Beyond Big Dams: Turning to Grass Roots Solutions on Water
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Nitya Jacob, a water and sanitation specialist at the Center for Science and Environment in New Delhi, warns that new toilets and decentralized waste treatment have the potential to put conventional sewage systems out of work “along with the rather corrupt engineers and bureaucrats that run these systems.” But he says the real obstacle will be to get city planners and developers to deploy something that challenges the concept of a toilet linked to a sewage system.

Still, Jacob welcomes the Gates initiative because the new designs for toilets eliminate the need for traditional sewage treatment systems. That, he says, holds promise for both developing and developed world settings.

I, too, welcomed news of the Gates awards, hoping the publicity might encourage people who have come to take toilets and sewer systems for granted to give this issue some thought. In the United States, sewage treatment has not been a problem for the past half-century, but it could become one again as infrastructure ages and fails — especially if there is a lack of government money to replace it. In addition, certain regions of the U.S. are expected to experience water shortages as temperatures rise. New, water-saving, decentralized toilet technologies may need to be adopted not only in places like South Asia, but also in parts of the industrialized world.


Cheryl Colopy researched and wrote her book, Dirty, Sacred Rivers: Confronting South Asia’s Water Crisis, during seven years of travel and residence in South Asia. With the help of a Fulbright fellowship she undertook her exploration of the Ganges River Basin. She is an award-winning reporter, formerly with National Public Radio affiliate KQED in San Francisco.

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Very interesting post.

Sanitation is about where people go to the bathroom and what happens to their waste. Sanitation facilities include toilets, sewers and wastewater treatment plants as well as more simple technologies such as latrines and septic tanks. Sanitation continues to remain one of the key health issues in the developing world: 2.5 billion people, over a third of the world's population, lack access to adequate sanitation facilities, perpetuating disease and high rates of child mortality. In order to address extreme poverty and global diseases, we most focus on achieving universal access to sanitation.

Human waste is full of dangerous bacteria that can cause diseases like cholera, typhoid, infectious hepatitis, polio, cryptosporidiosis, and ascariasis. When waste is not properly managed, it can come into contact with skin, water, insects and other things that ultimately transfer the bacteria back into the human body where it can make people sick.

The most common illness associated with poor sanitation is diarrhea. In developed countries, diarrhea is little more than a nuisance, but for millions of children in the developing world, it's a death sentence.

The primary purpose of good sanitation is health (through disease prevention). Despite the overwhelming importance of sanitation, the world is far behind in providing universal access to safe and hygienic toilets, and the poor are the overwhelming majority of those who miss out.

•      1.2 billion people do not have a toilet .
•      Not all toilets are sanitary: 2.5 billion people do not have somewhere safe, private or hygienic to go to the toilet.
•      Appropriate sanitation is driver of good health and human development, which can enable pro-poor economic growth.
•      In fact, a recent survey conducted by the British Medical Journal identified sanitation as the greatest medical invention in the last 150 years.
•      One gram of faeces can contain 10 million viruses, one million bacteria, 1,000 parasite cysts and 100 parasite eggs.
•      Poor sanitation is most likely the single biggest contributing factor to child mortality in the developing world . About 5000 children die from diarrhoea-related diseases every day.
•      Sanitation is the single most cost-effective major public health intervention to reduce child mortality. The simple act of washing hands with soap and water after going to the toilet can reduce the likelihood of contracting diarrhoeal diseases by over 40 percent.
•      Improvements in sanitation have strong flow-on effects to other aspects of human development.
•      Poor sanitation disproportionally affects women, impacting their health, dignity and opportunities for education.
•      Sanitation in urban areas is nearly double that of rural areas. For those not familiar with the fascinating world of urinal technology: “Conventional urinals use at least three liters of water per flush (about a gallon), whereas flush less urinals need neither water nor a flushing system. Special glazes give sanitary-ware urinals a pore-free surface, while urinals made of synthetic material have a long-lasting gel coating that repels liquids. The urine flows off the smooth surface of the urinal into a siphon. The siphon contains a liquid sealant that has a specific density that is lighter-than-water. This floats to the top, allowing the urine to flow through it and away, taking any odors with it. The liquid sealant remains in the siphon.

Fleshless urinals have no joints or cracks in which bacteria can colonize. The special surface repels most liquids and impurities. Cleaning therefore involves less cost and effort than with conventional systems, and strong toilet cleaners are unnecessary.”

In fact water is the most precious commodity in the developing world espe3cially in the rural areas. Flush out means more use of water. The present Septic tank toilet suits much for urban and semi urban areas in developing countries. Rural people are in the habit of going with a small utensil with water to open places . Though this is hygienically not welcome, the rural people have been habituated.

Any toilet for developing countries to succeed should use less water.

Dr. A. Jagadeesh Nellore(AP), India

Posted by Dr.A.Jagadeesh on 11 Oct 2012

Inodoros saludables, ecologicamente!!

Posted by on 11 Oct 2012

Cheryl Colopy, thank you for this article and Dr.A.Jagadeesh, thank you for your interesting comment.

There are a few observations I would like to make.

First, although faeces have the potential to carry disease organisms, if the person(s) producing the faeces are infected, (probably a high proportion of people in tropical climates), the idea that every bit of excreta is something to be truly frighted of can lead to fecophobia, and a reluctance to deal with disposal in a sensible, effective manner.

Secondly, in counties like India, where the preferred method of defaecation is to squat, we should not be trying to change that. In fact the "western" method of sitting on a pedestal in order to evacuate the bowel is very unhealthy from a physiological point of view. I am not trying to tell every one in the "west" to change their habits, just that we should not pass on bad practice just because we think it's "civilised."

Thirdly, sophisticated technologies, even those trying to minimise the use (abuse) of water for flushing toilets, can be prone to breakdown and malfunction. The separation of urine from faeces in the toilet pedestal is not necessary, if a proper composting process is practised.
In a separation toilet the urine outlet often gets blocked and most people with any self-respect would be most unwilling to do the job of unblocking it. If used in a private house then the occupants are more likely to maintain the toilet properly, but in a public facility I would not be recommending the separation toilet at all.

Finally, no mention has been made either in the Gates Foundation literature or in Cheryl's article above, of the Humanure system of composting, developed and perfected by Joseph Jenkins.

This system is extremely adaptable to different environments and circumstances. It's very cheap to make and establish. I am tempted to use the word "install," yet there is no expense at all in "plumbing," because there isn't any! It's very suitable for setting up a collection service and composting at a municipal facility.

Far from the excreta, faeces and urine, being a "waste," or a "nuisance," it is instead a valuable resource which helps to recycle the nutrients which our bodies do not need, and reduce the need for artificial fertilisers.

Operated properly the Humanure system is extremely effective in eliminating pathogens of all kinds.

Posted by Alan J Marshall on 11 Oct 2012

This is a great review of the issue including a waterless vacuum system from the 1870s
(thanks to Low-tech website!)

Thanks to the application of human "waste" products as fertilizers to agricultural fields, the East managed to feed a large population without polluting their drinking water. Meanwhile, cities in medieval Europe turned into open sewers. The concept was modernized in late 19th century Holland, with Charles Liernur's sophisticated vacuum sewer system.

Posted by M Munn on 11 Oct 2012

While recently in Europe I inspected a new biogas facility which used corn, grasses and cow manure, conveyed from a dairy close by, to produce methane gas which was piped to motors which generated electricity for the grid. The waste left was then spread by tanker back on the fields for fertiliser. I was told that the high internal temperatures sterilise the mix. This plant had input of around 50 tonnes per day and produced around 950 kw of power. In principle it seems that human waste could be utilised with similar technology, thereby being a valuable renewable energy source. Is anyone using this technology for human waste?

Posted by Ron Wilson on 12 Oct 2012

Decades ago there was an attempt to convince people that wetlands were your best means of turning human waste not only into healthy biomass but water that was far cleaner and without the toxic chemicals that are currently used. Sadly that has seemed to have disappeared. Perhaps it is the unwillingness of humans to give up the land that humans must be kept out of...

Posted by Donna Kat on 14 Oct 2012

@ Ron,

I think farmers in rural China use anaerobic digesters to treat both human and animal faeces and turn them into biogas and fertilizer.

However, I am afraid that human waste alone wouldn't do the trick, although I'm not sure about that.

Vietnam was one of the first developing nations to use the composting latrine described above in the 1970s. Its sanitation programme was so successful that it is still referred to today by specialists.

Appropriate technology and political will can do miracles, but beware of any silver bullet. Each intervention must be tailored to the specific community it targets.

Posted by Olmo Forni on 16 Oct 2012

As I understand it, anaerobic digestion preserves a greater proportion of the nitrogen, improving the effluent for agricultural applications.

Yet the potential pathogens in the human excrement will not be sufficiently reduced to make applications of the fertiliser safe.

This presumably is the case with the method used in China for many years. Have they found it possible, with the industrialisation of their population, to spread the "night soil" over a wide enough area for the natural environment to deal with it?

Even though the predominantly aerobic Humanure method might lose more of the nitrogen content, I suggest that the increased microbial activity, which can be imparted back to the agricultural land, would soon make up for that nitrogen loss.

It would be useful to get some scientific knowledge here in this forum, as my suggestion(s) are to some extent theoretical.

Posted by Alan J Marshall on 22 Oct 2012

Sanitation is very important, but this is also part of another large problem that humanity needs to face: the broken nutrient cycle, and the unsustainable chemical-based 'conventional' agricultural model that has resulted.

In the past (and in nature), food was consumed where it was raised or grown, and the resulting manure was returned to the site to fertilize the plants for the next harvest. It was a self-contained cycle of sustenance and fertilization.

As people became concentrated in larger and larger cities, however, things changed. The plant and animal foods were harvested on farmland and then shipped to cities, and instead of being returned to the source site to feed future crops, the resulting manure was flushed into the rivers and out to sea. Nature's nutrient cycle was broken, and without replenishment, soil inevitably became exhausted and barren.

A German chemist named Justus von Liebig understood that the solution to both exhausted agricultural soils and waste disposal problems in cities was to return the vital nutrients to the farmlands. But people were accustomed to their flush toilets and governments chose to pipe sewage into the sea instead, so he began to work on another solution: artificial chemical fertilizers.

We now have an agricultural system fed by fossil-fuel-based chemical fertilizers. Organic matter which previously sequestered massive amounts of CO2 and helped store moisture and nutrients to nurture plants has been burned out throughout our farmlands by chemical fertilizer use. Our farmlands are really now just dead dust, with crops kept alive on an IV drip of synthetic chemical fertilizers. Much of the CO2 that humans have released into the atmosphere has come from degraded farmlands. Since food is only as good as the soil it was grown in, the nutritional value of our food has declined. Dead zones from chemical fertilizer runoff grow every year in the world's oceans.

The whole point of organic agriculture is to return to using nature's methods of growing plants and animals (and ourselves) as part of a sustainable cycle. Farmland cared for in this manner builds up organic matter that feeds plants and also sequesters carbon. Returning to organic
methods on a large scale could (once again) sequester CO2, as well as provide us with healthier food. We would use less fossil fuels.

These new toilet technologies fit into this concept quite well. These ideas aren't only important for the developing world. Humans as a species need to rethink waste disposal and fix the broken nutrient cycle.

Posted by Tom on 30 Nov 2012

It appears that separation of moisture is key to collection and disposal of waste.
1. Separate the urine
2. Dry out the human waste, through solar/wind energy (available in plenty)
3. Device a collection and packaging system that could be used to re-distribute this as organic fertilizer.

We should also keep in mind security, privacy and convenience while designing these toilets. I'd love to be involved in the redesign of these systems for impacting humanity in a big way.

Anil Murthy

Posted by Anil Murthy on 10 Mar 2013

The problem isn't water born disease caused by untreated sewage - the problem is TOO MUCH SEWAGE. The solution isn't better toilets, it's less people creating sewage. INVEST IN BIRTH CONTROL otherwise the 1.5 million that would have died because of the fallout of untreated sewage will now die of starvation or war. TOO MANY PEOPLE is the problem - FEWER PEOPLE is the solution - it's not rocket science.

Posted by VonSkippy on 10 Mar 2013

Water is a scarce resource. Polluting natural water resources first through sewage than later to be treated and making it potable again is not a justifiable sustainable way. Waterless sanitation is highly hygienic and way towards less carbon footprints.

Posted by Neha Bagoria on 11 Mar 2013



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