Sh*t happens. We can deal with it.

Most northerners don't know sh*t.

Most of us don't understand sh*t.

But I know my sh*t.

I know my sh*t, not because I'm a “professional”, but because I try things at home. And when something works for me at home, then and only then do I take it "on the road" and work on implementing what works for me in other communities around the world .  Rather than having the hubrus to "think globally" and then act locally (which always seemed backwards to me!) I "think locally" and then, by solving my own problems and openly sharing the results - the successes and failures - with my worldwide social network through our facebook group "Solar CITIES Biogas Innoventors and Practitioners" (http://facebook.com/methanogens) we find that in fact we are acting globally. We get to know our sh*t together, collectively, iteratively, through trial and error and shared experience rather than hearsay, fiat and decree.

I know my sh*t, not because I'm an “expert” but because I take care of my own sh*t. I've been building and using my own composting toilets and biodigesters for more than 15 years.In my apartment in the Los Angeles Eco-village I started getting into deep sh*t with the paint bucket toilet system found in Joseph Jenkins Humanure Handbook (you can get the entire book free here. It has all the data you need to understand how easiy it is to safely deal with humanure, a.k.a. "sh*t"). Since then I've strived  to avoid letting the results of my consumption become somebody else's problem.

Sometimes, like everybody else, I'm full of sh*t. But when the sh*t goes down, it is quickly and safely recycled into the precious life giving organic matter it was intended to be. That way the sh*t never hits the fan. Mine doesn't get distributed over hell and high water, giving hell to others. My sh*t can never be a source of filth and disease, odor or infirmity. My sh*t stinks like everybody else's upon production, but because of the way I treat it at home it never releases its thiols/mercaptans and phenols and sulfuric compounds to the environment and will never attract flies or permit the transmission of cholera, dysentary, typhoid or E. coli contamination. What goes on in Vegas stays in Vegas, and what goes on en mi casa will never affect tu casa. I don't give my sh*t away to nobody. You'd have to fight me to steal my shi*t. I take care of my sh*t. Most northerners don't.

Southerners used to understand sh*t. Probably many northerners too. But south of the border, down Mexico way, and in all of the countries between the tropics of capricorn and cancer, the recycling of shit was so fast that it rarely posed a problem prior to the absurd human and “pest species” population growth that characterized the 20th century. After all, every animal that lives and that ever lived (and the tropics had the lions share of every phylum) sh*ts in its environment, and none had waste treatment plants. Fish and aquatic mammals sh*t in the very water they drink, and that we drink too, but their sh*t is so quickly taken up as food by other organisms that it rarely if ever permits the accumulation of pathogenic microbes in threatening quantities. Our own sh*t, released into an environment rich in biodiversity, also became immediate feedstock for plants and animals and fungi. And when we concentrated in certain places, as long as we kept our sh*t out of our immediate drinking water supplies, it posed no threat. Safety came from efficient cycling. As long as we didn't overwhelm the absorbtive capacity of a given ecosystem dealing with sh*t was easy.

I had a teacher once who chided those of us in the eco-village movement for thinking we could use natural processes to deal with sh*t in tropical countries. In the late 1990s we showed her a video of the John Todd Living Machine that I had learned about at Harvard in 1980 when I visited the New Alchemy Institute on Cape Cod (I and my Mercy College students visited a functioning version of the technology called the “Eco-Machine” at the Omega Institute in New York a couple of weeks ago). My professor told us “you can't apply these biological processes to the tropics and sub-tropics; you will end up killing people”. When we asked why, she said “you obviously have no understanding of the ecology of the south, in hot humid environments disease runs rampant. Bacteria grow everywhere. Flies will breed like... well, like flies. These living machines will be a disaster”

The outdoor wicking beds at the Eco-Machine at the Omega Institute with returning cattails and other constructed wetland plants emerging after the spring thaw.  These wicking beds, we were told on our recent visit, are the heart of the effective waste-water treatment that goes on at Omega in New York. By summer time this will look like a naturally wetland, thick with greenery  The inside part in the building  is the sexier "finishing" part of the process, but the beautiful vegetated gravel pits are where the real heavy lifting occurs, eliminating any problems that so called "black-water" might cause.  The inside section helps to eliminate the problems associate with the more difficult issue in waste water: soaps and detergents, NOT sh*t.

The inside of a John Todd style Eco-Machine or Living Machine at the Omega Institute in New York.  It uses plants, fish, snails and microorganisms to create clean water from toilet wastes and washing and cleaning wastes, treating both "black water" and "grey water".

She was well intentioned but ignorant of the facts. In fact the rapid growth of all organisms made possible by the warmth and wetness of the southern latitudes makes living machines much more effective there than in the north. If disease is spreading in the south it is because, following the “western” model of development, people have radically diminished the transformative capacity of the ecosystem by cutting down forests, altering watersheds, monocropping, spreading poisononous herbicides and pesticides, impoverishing biodiversity, overfishing, poisoning lakes and streams and rivers and oceans with soaps and detergents, causing eutrophication and hypoxia. Under these conditions, along with the extra warmth and wetness, can pathogenic and pestulent creatures experience out of control population explosions? Si, se puede! But those same conditions also give complex ecosystems an edge, enabling the establishment of regimes that make short work of errant “bad guys”.

 It is for this reason that waste water treatment using the schmutzdecke system (a German description of a natural process that occurs in ponds in the warmer latitudes) works so well in the south. In a schmutzdecke system a rich population of interrelated organisms (microbes, algae, protozoa, water insects) is cultured above a slow sand filter and contaminated water is dripped in slowly enough that it doesn't disturb the complexity of the aquatic ecosystem. This shmutzdecke (which means “dirty layer” and needs to be about 20 cm deep) actually cleans the dirty water by eating all the pathogens. Residual microbes are trapped by electrostatic and mechanical forces in the fine sand layer (which needs to be at least 75 cm deep for proper effectiveness).

When I tried making one at home in Germany it worked pretty well in the summer but stopped working in the winter. Of course. And while it appears to take care of bacteria that can cause disease (development agencies are using them effectively in Afghanistan) it does nothing to eliminate the awful smell and taste of greywater. My experiments with my Shmutzdecke system convinced me that if anything, dealing with soap is much harder than dealing with sh*t! And I would have continued my experiments except that living in the north made it so hard to harness the biology properly. No wonder northerners are so down on biological treatment – we rarely get a chance to see it work. Hence the culture of chemical extermination we've created and promulgated around the world.

The author experimenting with his own home scale schmutzdecke system. Video here.

So-called Western culture, (which, given the rotation of the Earth along a north-south axis, and the distribution of major landmasses above and below the equator, is a misnomer), has evolved an unfortunate fecophobia that is coupled with a certain conversational smugness that inhibits rational discussion of sh*t. The fact that I feel compelled to use an asterix in place of the letter I in the word is testimony to the taboo we have in our society – I don't want to risk offending anybody by calling the result of eating by its vernacular.

Later on in this essay I will resort to using Latin descriptions like 'feces” or “fecal matter” but parsimony suggests that when writing expositions like this it is better to use four letters (even if one of them is a symbol) instead of five or eleven. Westerners are supposed to be appreciative of efficiency.

Anyway, the society in question is really northern hemisphere society, not western. The native Americans were as west as you can get from England and many of their members told the anthropological psychologist Erik Erikson that they found the European practice of crapping into rivers and streams an abomination. Indigenous peoples around the world were the inventors of some of the first composting toilets; Eriksson reportd that the native American habit was to do your business in the forest, as far from bodies of water as possible, so that the insects and worms could quickly recycle it back into the forest. Does a bear sh*t in the woods? You betcha!

I am asserting that perhaps northerners didn't get sh*t and its transformative properties (with the very very notable exceptions of people like Joseph Jenkins and the Austrian artist/artchitect/activist Hundertwasser whose "Shit Culture Manifesto" should be on every development program's reading list)  because they didn't understand biology and how to deal with winter. Sh*tting on snow leaves a prolonged and unsightly mess, particularly when accompanied by the yellow stain of urine, and it is a mess that will last for months until the spring thaw. At that time biological systems are struggling to re-establish themselves and it is easy for ecological systems to get out of kilter. If the sh*t is too concentrated in an area and there isn't enough biodiversity hopping to balance the flow of nutrients, the “bad guys” can predominate. How much more convenient to sh*t in a river and let the lumps of digested food waste become somebody else's problem. “Not in my backyard” became “why not in everybody elses?”. The tragedy of the commons reared its ugly sh*tty head … as well as the tragedy of the less fortunate downstream.

There were those, of course, who did try to contain their sh*t, but most northerners, sh*tting into an outhouse pit or ditch, trying desperately to hide the “shame” of their defecation, never seem to have figured out that they could simply use a bit of insulation (straw would have done fine, sawdust and ashes are the norm, grass and green leaves are even better) to line their pit, do their business, and then throw some more straw or grass or leaves on top, increasing the carbon to nitrogen ratio to the point where exothermia sets in, creating a thermophilic compost pile that rapidly turns sh*t back into soil (the original source of sh*t, transduced through plants to animals to sh*t and back to soil again through solar energy). When it comes to the basic biology of soil formation, most northerners apparently never got the memo, and where sh*t wasn't being flushed away into rivers and streams causing deadly outbreaks of cholera and dysentary and typhoid and E. coli poisoning, more or less contained outhouses all over stank to high heaven, the stink attracted numerous flies, and contamination of ground water become a historical life threatening problem. It never had to be that way.

Of course I can't indict all northerners. In the Himalayas in Nepal I visited plenty of traditional Sherpa villages on our National Geographic expeditions where they have been doing composting toilets for thousands of years – forget digging a ditch (the soil is too rocky and frozen), the clever Sherpa built toilets elevated above a stone chamber filled with rhododendron leaves, and provided piles of rhododendron leaves next to the toilet hole for “flushing” with the pleasant smelling cover material and used the heat of decomposition to partially warm their houses. But then, nobody really considers the Nepalese northerners or westerners. With both terms we really mean “the descendents of the Europeans” and it is, I believe, our cultural hegemony that makes dealing with sh*t so messy.

Northerners don't know sh*t. We've created a culture of flush and forget, relegating the transformation of sh*t nto non-sh*t to a few engineers , most of whom have been schooled in chemical obliteration as the solution to everything. Disinfection is the mantra of the northern world in response to the workings of biology at the digestion or “production' end of the tube that is the human animal, just as pesticide and herbicide and fungicide and sterilization is the mantra at the consumption end of the tube. Kill everything you can before you put your food in your mouth and kill everything you can when the results come out (and don't forget to use mouthwash and antibiotic soaps and take your antibiotic pills to disinfect your whole body in the in-between while you are at it!).

In these troubled times, with the legacy of historical colonialism and the nightmare of neo-colonialism still impeding self-determination in southern countries, the north-south vector of development aid and “expertise” is a most unfortunate thing. Because most northerners don't understand how small a problem sh*it really is, and how easily solved, the descendants of the colonized in tropical and sub-tropical countries, where proper temperatures and biodiversity can turn sh*t back into soil in a matter of days, emulate the sh*tty practices of their colonizers, having forgotten how easy it was and is to avoid all the problems sh*t entails and actually make of it a value added enterprise.

Sh*t looms large in the consciousness of Euro-American culture, particularly North American culture, like the shadow of a hand puppet that looks like a giant marauding bear on the wall until you have the courage to turn around and see it for what it really is – a really precious feedstock for the very process of life, rich not only because of its chemical constituents but because of the very bacteria and other microbes (Archaens aka “methanogens” – a life form distinct from and much more ancient than bacteria that transsubstantiate sh*t into recoverable energy in the form of methane).

An illustration of the difficulty most northerners (and most of their descendants, wherever they may live after the conquest) have with understanding sh*t comes from my recent work in Brazil where we are trying to solve grave waste management and sanitation problems. I will be blunt and politically incorrect and say that most of the white people I work with around the world really believe that sanitation is a difficult technical issue that requires long processes of technical study and huge investments to solve. They look to investment intensive and massive centralized waste-water treatment plants for the answer to the filth that flows into the lagoons and bays of Rio de Janeiro. They frown uncertainly when it is suggested that all the sh*t related problems can be dealt with much more simply and effectively using small anaerobic digestors and wicking gravel beds and compost bins or aeration tans. They balk at the idea of open constructed wetlands and the use of banana trees for transpiration and nutrient uptake, somehow offended by the idea that sh*t can be taken care of without the use of chemical weapons – “germicides” like chlorine (the famous chemical in the deadly mustard gas of World War I). The thought that organic material and chlorine combine to form carcinogenic compounds that persist in the water barely crosses their minds – as long as we “obliterate” the invisible enemy they call “germs” we can let the hospitals deal with the suffering of the survivors of our “carpet bombing” strategy for disinfection.

Constructed wetland for treating toilet waste built by the community at the Alemao Verdejar Favela in Rio Arguably much prettier than a septic tank or waste water treatment plant.

Another view of the constructed wetland at the Alemao Verdejar Favela in Rio

Constructed wetland at the Alemao Verdejar Favela in Rio

The Constructed wetland at the Alemao Verdejar Favela in Rio built by the community uses a bed of used automobile tires and gravel cemented into place and planted with banana trees and other vegetation.  It processes toilet wastes from the community creating fertile soil while the banana trees transpire and evaporate the liquids.

Constructed wetland at the Alemao Verdejar Favela in Rio

A hand made mini kitchen biogas system designed and  built by Solar CITIES on a travel grant from Solar Cities Solutions in Alemao Verdejar from a Rotoplas tank.

The hand-made  Solar CITIES Rotoplas mini biogas system for kitchen waste with a food grinder donated by Insinkerator corporation to assist in the biodigestion.

On the left is a three drum vermicomposting system that the favela had already installed in the kitchen. Behind it is the hand-made  Solar CITIES Rotoplas kitchen digester prototype built by T.H. Culhane and Luis Felipe Vasconcellos when T.H. was visiting on a trip funded by Solar Cities Solutions  in the summer of 2013 to explore larger Puxin type community digesters for treating toilet and food wastes in Niteroi and Rio. An Insinkerator food grinder sits in the foreground which will be used to feed the digester.

Ironically, some of the most dreaded consequences of improperly processed sh*t actually aren't so hard to manage. Yes it is true that one of the weeks I was in Nigeria building biodigesters for schools and hospitals with former president Obasanjo to help turn sh*t into safe fuel and fertilizer, 900 children died due to a cholera outbreak in the city of Lagos when a sewer pipe broke and fecal material contaminated the drinking water supply. Also, flooding in the city while we were there due to plastic bags filled with food waste clogging the sewer drains backed up fecal laden water into the streets. All of this death and misery could have been avoided if both sh*t and food waste were routinely placed into biodigesters. But what is far too infrequently told outside of medical clinics in the “third world” is that cholera and other water-borne illnesses aren't really the danger they appear to be and are readily treatable. The reason for so many tragic deaths from fecal contamination is usually dehydration. Babies, children and the elderly will get cholera or shigella from contaminated water and these organisms produce toxins that inhibit water retention so that they can pass through the body and back into the water to complete their life cycle. The body responds through diarrhea, eager to flush the invaders out. If the diarrhea is not deposited back in the water, the infection dies out. If the body of the host is kept hydrated with a solution of electrolytes (the right sugars and salts) the infection can run its course without mortality. Millions and millions of lives can be saved by simple interventions of rehydration and monitoring.

 If sh*t is causing nightmares in developing countries it has more to do with our lack of investment and attention in proper affordable and available medical treatment than the true danger of the pathogens in sh*t. Most of them are much more benign than the pathogens that can result from organisms dining on our food waste – the plagues of Europe were the result of improper treatment of high-energy organic residuals preyed upon by flea bearing rats, not improper treatment of sh*t. Airborne infections, like influenza and other viruses carried by absurd concentrations of domestic animals (avian flu, swine flu etc.) are what I fear most when I travel, along with salmonella and other forms of food poisoning, almost all the result of a paucity of diversity in our food supply and our tendency to crowd animals and plants of the same species together. Death by proximity to another person or animal scares the sh*t out of me. I can avoid most of the diseases and problems sh*t brings by boiling or purifying my water and washing my fruits and vegetables and, if necessary, hydrating myself when I get ill. Diarrhea I can deal with.

For my part, having lived and worked in areas with poor sanitation for many years, I've never had such a phobia for feces. Fecophobia, which is extant in the north, doesn't seem to be a part of the “threat level orange” response of most people in the south because, as mentioned, most sh*t degrades rather quickly in a landscape filled with worms and insects and fish and reptiles and birds and mammals and a trillion different kinds of protozoa and bacteria and archaea that we haven't even begun to identify (all of which are sh*tting too, every day). The scarab beetle, sacred to the ancient Egyptians, is actually the dung beetle, and one of the reasons it was sacred is because of how quickly and effectively it carried off our sh*t and turned it back into life giving soil.

I can never forget living in the jungles of Borneo for a year on a Harvard University research team in the mid 1980s and marvelling nights when I squatted over our dung pits in the forest near our huts watching the ruby red eyes of the dung beetles magically approach as soon as I had done my business. With a gentle whir of their wings they would dive bomb between my legs, quickly roll up a ball of sh*t larger than themselves and then take flight, whizzing up and out with a tickle of air on my bum, taking the gift of my sh*t to their lairs to cultivate with the aid of fungi into food for their larvae.

On other occasions in Borneo we found ourselves in pools of flowing water where it was actually appropriate to sh*t in the water because hungry fish were waiting and as soon as you dropped your load they snatched it up in a flurry of writhing scales and fins. This interest by fish in human feces was well noted by Indonesians; in Sumatera we visited a restaurant built over an artificial fish pond that had bird cages also suspended over the pond. The birds were there to feed the fish with their feces, but on inspection I noticed that the toilet for the human patrons also discharged directly into the pond. I was told that the fish we were eating were also fed by us. Cooked properly, they assured me, it was quite safe. I'm not sure about that (even I have my limits when trying to suspend disbelief) but I finished my meal and I didn't get sick, nor did anybody else.

In a Dyak village in Kalimantan Timor I dined with a tribal chief whose hut was built on stilts in two stories with the bedroom and bathroom on the second floor. The toilet was a hole in the slotted wooden floor underneath which the chief's “babi hutan” or forest pigs lived. They ate all our sh*t and we in turn dined on them, and so the cycle completed itself.

During visits to Quitos, Ecuador and the Meskital slums of Guatemala city I used composting toilets that I built using the Jenkins “Humanure Handbook” paint bucket method to avoid problems when the electricity would go out for a week and none of the flush toilets worked, and I used the same system for three years in my apartment in Los Angeles at the Urban Eco-village, planting trees with my “wastes” so they wouldn't be wasted”. I've since used my own sh*t, and that of my two children when they were in diapers, to start and continue to produce methane in home built biodigesters on our porch in Germany and in New York. I've taken 100 liter tanks and filled them with sh*t on my porch and run air through them and watched as algae grew and completely removed all smell and danger in a matter of weeks.

Basically sh*t doesn't scare me. It is the least threatening output of the human condition, much more tractable than the chemicals we use routinely to spray our food and the produce of our gardens before we eat them and turn them into sh*t. And I would argue that sh*t is much less of a problem than food waste as an engineering problem although that too has a simple solution. And both are really trivial compared to the “grey water problem” – that grey area in waste treatment where you have to deal with the awful effects of chemical soaps – basically salts and fats and perfumes and antibacterial toxic inhibitors – on waterways. Yet that too can be simply, if more expensively solved, using the “living machines” or “eco-machines” a la John Todd that I spoke of earlier (basically constructed wetlands and tanks with lots of plants, algae, fish and snails, wonderful snails). The right quantity and diversity of life forms in the right formations can take care of everything organic we throw at it. It is the inorganic material – the poisons we put in our environment – that is the only real threat.

The two Puxin 4m3 toilet waste digesters and one 10m3 food waste digester built by Solar Cities Solutions at an elementary school in Niteroi, Brazil.  For maximum efficiency the two systems should be connected but concerns about safety of the toilet digesters require that we keep them separate until we can prove zero pathogenicity.

Meanwhile, in Brazil, as “foreign experts” riding in on our decidedly white horses to save the day in our bid to “help the poor” in the favelas, we are arguing endlessly about how we are going to “deal with” the “sanitation problem”. As if it hadn't already been solved. And while we Norte Americanos try to call our engineering acumen into play, negotiating with agencies and drawing up plans and planning public relations bonanzas to level up our projects once we have our “first successful demonstration”, the Central Americans, Mexicans in particular, are quietly going about their business in how to treat the result of us “doing our business” (sh*tting), creating business empires at the same time as they save lives in communities.

The two toilet waste treatment digester tanks before infill. The first tank, on the left acts as a settling chamber and primary digester. The supernatant flows into the second tank where internal surface area further cures the liquid, which then flows back out to a constructed wetland that Solar Cities Solutions team member Marcello Ambrosia is building proposed by team member Yair Teller in discussions with Executive Director Gail Richardson and Creative Director T.H. Culhane and funded by the Insinkerator corporation.

Around the world many companies are beginning to understand sh*t and providing effective low cost solutions to what was once a scourge of humanity.  One huge Mexican company in particular – Rotoplas - has already installed more than 200,000 “Bano Dignos” in Latin America with the support of the Mexican and Brazilian governments, completely eliminating the threat of human waste from each household by working incrementally, household by household. They will soon be up to half a million installations. Eschewing the idea of large treatment plants for economic, topographic, logistical and social reasons, they simply provide to families a complete home scaled system called the “Bano Digno” or “dignified toilet”. It consists of a rain water collection tank, a manual pump, a fiberglass molded outhouse with flush toilet and gravity feed water storage container and a small biodigester system that in turn consists of a 1300 liter plastic rotomolded anaerobic chamber, a contained wicking bed (gravel filled plastic chamber of about 400 liters) and a sludge collection tank of a couple hundred liters that enables “self-cleaning” of the digestor and yearly home processing with lime powder to provide good soil for growing plants.

Each part of the system is modular and can be installed all at once or iteratively, depending on the circumstances and need. The systems scale up for larger families and institutions and can be installed in a day. 600 liter systems are available for families of up to 5 people, 1300 liter systems for families up to 10 people, 3000 liter systems for community centers with up to 20 people, and 7000 liter systems for schools and institutions with up to 60 people.  Multiple systems can be concatenated for larger institutions.  While the complete systems may be  too expensive for most poor families to afford as an initial capital outlay, the governments of Mexico and Brazil and other countries subsidize most of the cost as part of their role in supplying social welfare infrastructure and microloan programs are being considered.

 The Rotoplas Bano Digno Biodigestores are already sold in Rio De Janeiro at Leroy Martin and other chain hardware stores all over Brazil so there is no technological or logistical hurdle involved in eliminating current scourge caused by improperly treated human wastes.  The issue now is purely financial and this is where governmental, non-governmental and other organizations can focus. 

The Rotoplas Bano Digno biodigestor  intervention is so simple and elegant and readily available that for dignity focused projects like the one that the Brazilian NGO Catalytic Communities is creating with favela community leaders  in Muzema it would make the most sense to immediately become part of the program the Rotoplas company already has with the Brazilian government to install hundreds of thousands of household digesters at a subsidized cost and work from there. Can we do this? Si, se puede!

Anybody who doubts the potential of home scale biodigesters to rapidly enter the market and positively impact sustainable development also severely underestimates the power and magic of Mexico. This will be the real revenge of Montezuma, when his people end dysentery. cholera and other waterborne diseases all while also giving clean reliable fuel and fertilizer to make deserts bloom once those features are added to the existing solution set. 

I have now had the pleasure of working with the good folks at Rotoplas to help improve the home scale biodigesters they manufacture and deploy by adding two dimensions to their project – 1) to slightly modify the existing systems so the methane they naturally produce can be captured and utilized (for example, to cook and boil water, and improve the temperature of the digester so it can process more effectively, insuring that disease does not spread if it is present) and 2) to radically increase the amount of useful methane they produce through the addition of ground up food waste, spoiled fruits and vegetables, flowers and other energy rich organic residuals (thereby increasing the utility of the above). A third improvement is the use of solar heated or gas heated water (post consumer use in showers) to further raise the effective temperature of the digestor to get maximum output. But regardless of whether we add heat or other organic wastes to the system and thereby enable people to have clean, smoke free biogas or just leave them the way they are to more slowly treat the human wastes alone, the simplicity of the system makes a mockery of many of the brow furrowing long winded discussions going on in the north about how to solve sanitation problems in the south. As the Emerson Electronics slogan goes, “consider it solved”.

And of course, adding solutions like the Emerson/Insinkerator food-grinders (or local equivalent) to the Rotoplas Bano Digno solution really does add dimensions that can really radically improve their efficiency. High calorie organic residuals are a huge benefit to biodigestion processes while being a bane to society when simply discarded.

I will continue to argue (and here I depart from many of my fellow northern specialists) that food wastes actually are more of a burden to society than toilet wastes.

Looked at from one perspective (a non fecophobic perspective) toilet wastes ARE food wastes – food wastes that have been “pre-digested” because they have been digested by us. In this sense toilet wastes are already broken down by the appropriate microbes using our stomachs and intestines as the anaerobic reactors for partial hydrolytic, acidogenic, acetogenic and methanogenic processes. This is why you can use your own sh*t to start an effective biogas system (I used my babies' diaper wastes). We are biogas systems. We are anaerobic digesters. Yup, the proof that we are, in fact, biogas yielding biodigesters is that we fart. Our flatulance (another subject consider risibly taboo in polite discussion) is the indication that much of the energy found in our food does not make it to our cells. We release it into the air every day (I know, I know, ladies, you never pass gass, but we men do right?).

When you look at human beings as a tubular plug flow biodigester you see why our fear of sh*t is so unfounded – we've already started the process of transubstantiation of food back into soil. All our sh*t needs is more processing time in the airless phase and then a bit of time being exposed to aerobic bacteria, insects and worms and plants for finishing. To have allowed sh*t to have become a major health hazard (which only happens anyway when a few people with unbalanced internal and external ecosystems allow the invasion and growth of pathogens and then discharge them directly into drinking water supplies or onto vegetables – most people's sh*t is actually pathogen free!) is unconscionable. Treated at its origin through simple systems like the Rotoplas Bano Digno what was stupidly seen as the scourge of mankind can readily be turned into its greatest promise.

On the other hand I argue that food waste, which still contains an enormous amount of high calorie photsynthetic energy, is a far more formidable threat as it is dealt with by modern society (based on northern models of waste disposal). Because food waste is so energetic it attracts every member of the biosphere that needs that energy. Where toilet wastes can hardly support more than a handful of specialized detritivores like the aforementioned dung beetles and fish and pigs, there are legions of organisms, from bacteria to insects to higher birds and mammals that literally jump at the chance to dine at the banquet of our high calorie organic wastes.

One could very convincingly argue that the entire (and scandalous) loss of life from the “black death” or “bubonic plague” owes its tragic dimensions to the improper disposal of food wastes. Rats, originally forest rodents, invaded European cities like Remy in Ratatouille, looking for food waste. They carried with them the fleas that carried the microbe Yersinia pestis that caused the horrible plague. Had northerners simply composted the food waste, or used it in biodigesters (as myancestors, the Assyrians, did in the fertile crescent as long ago as1000 BC), there would have been nothing for the rats to eat, hence no urban rat population and hence no plague.

Similarly, all of the problems with cockroaches (another forest species that has made its way into the urban jungle to feast on our organic garbage) could be eliminated when food wastes are transformed in controlled conditions (sealed tanks or open compost facilities) into biogas and liquid or solid fertilizer. Then we wouldn't keep poisoning ourselves with foul smelling and toxic insecticides like the ones that were routinely sprayed in my apartment building when I was a child in New York. The same is true of flies. The same is true of ALL so called “vermin”. Stray dogs and cats, possums, racoons, avian flu bearing pigeons and other birds – none of them would last in the built environment long if we didn't stupidly generate food waste and leave it in bags and trash cans and dumpsters for “disposal” by the garbage industry. Home and community scale biodigesters would completely eliminate the threat they create – a threat much graver than toilet waste, which is not only of much lesser volume (each of us generates much less toilet waste on a per gram basis than food waste) but of little or no interest to such a wide variety of potential pests.

Another problem with food waste that we don't have with toilet waste is that food waste is generally transported to landfill or incineration (both significant causes of greenhouse gases) in plastic bags. One could argue that the real reason for the despoilation of our oceans and the mortality of marine life by plastic bags (now accumulating in the plastic vortex in the pacific ocean) and the real reason for the constant flooding of our streets and back ups of our sewage systems such as I experienced in Nigeria, spreading disease and carnage in cities around the world, is the build up of plastic bags that were thrown into the streets because they contained smelly food waste.

When food waste is put through a food waste grinder in the kitchen sink, or into compost bins or biodigesters, the number of plastic bags thrown away drops so dramatically that it no longer becomes a threat. Toilet wastes are much easier to manage in this sense than food wastes. Only in the slums of Nairobi has the author witnessed sh*t disposed of in plastic bags (the famous “flying bag of sh*t” in Mukuru and Kibera are the subject of much discussion because the city has provided no adequate sewage solution. Biodigesters will eliminate that practice if we move fast enough and get our priorities straight).

So on the whole I maintain that cleaning up food waste is a much higher priority than treating toilet wastes as it generates many more problems. Nature has been converting the predigested solids and liquids from animal asses back into soil since time began. The real issue with sanitation is simply keeping the sh*t out of the water supply, nothing more. And in impoverished areas this can be most easily achieved, in my opinion, using household and community scale digesters using the Rotoplas model developed in the south for handling the problems facing the south. When combined with food grinders, warm water feeding and gas collection improvements, the Rotoplas Bano Digno program can also tackle energy poverty and deforestation (along with the consequent erosion and flooding it causes) and prevent deaths and illnesses due to indoor air pollution. Further combined with vertical farming techniques and aeroponics, hydroponics and aquaponics, the proper home and community transformation of human and animal and food wastes can also provide food security and enhance health and nutrition on the input (feeding) side of the equation as well as the output (toilet and trash can) side.

Once we have these systems in place, we can move on to tackle the more intransigent grey water problem, which requires more surface area, exploring the use of gardens filled with plants and living machines to get rid of the smelly, toxic situation created by our irresponsible use of sodium laureth sulphate, phosphates, salts and other chemicals used in our synthetic soaps and detergents. These are substances that inhibit biodiversity and appropriate rapid recycling of resources, either by killing life forms or by causing huge unbalanced population explosions of species we consider pests. But that topic is for another day. For now let us celebrate the simplicity with which biological processes in the tropical and subtropical regions of the world can be harnessed household by household to clean up all of our organic wastes and put them back into service again. In the south, where small scale systems can best make use of the existing ecology of transformation, we can do this. But I wouldn't necessarily trust most northerners to understand this. Most of us northerners, fecophobic, even biophobic, and steeped in super-sized solutions and chemical warfare, simply don't understand sh*t. And that may have been the problem all along...

Still, sh*t happens.  And we can deal with it.