Good Book On The Disposal of Human Waste

Given the role that tiny houses are playing in leap frogging the old flush toilet/sewer system this book is filled with details worthy of a tiny house dweller since inevitably we will have many a conversation about how our composting toilet works. Plus it's a great read. I love accompanying a journalist in search of answers. Here I have noted my favorite takeaways from The Big Necessity: The Unmentionable World Of Human Waste And Why It Matters.

Rose George, a British writer after my own heart, extensively explores the unmentionable topic of the disposal of human excrement. This sends her on a worldwide journey investigating toilets and sewage treatment or lack thereof. Her journey begins in the London sewers with the flushers—crews of professionals who maintain these underground pipes. The enemy of the flushers is restaurant fat. Massive amounts that stinks more than poo and is hard to remove. She does a similar tour in New York. Here it is confirmed that New York sewers (and likely the cities of many a reader) are designed to discharge raw sewage into the nearest waterway when overwhelmed by rain. This happens about once a week in New York.

At the opposite end of the system sits the throne toilet unchanged for decades until the Japanese took it to new heights of function by making this unmentionable household feature marketable for multiple upgrades–a marketing feat in this story. Japanese toilets famously can adapt to their owners habits and monitor their health while cleansing them with warm jets of water and heated air to dry them. I’m seeing them in the restrooms of high end shopping malls in Bangkok now.

But most fascinating of all is the human story. No serious book about toilets would be complete without addressing those who have none. For this we must visit the rural villages of India and Bangladesh and learn that just imposing toilets from on high does nothing to dissuade people from open defecation. Authorities armed with facts on the dangers of feces will not force sanitation to become a priority for poor people. It takes a skillful engagement of the villagers to realize for themselves that they want toilets. The slow way is to bribe with offers of running water and wash rooms if an investment is made in a latrine. The most effective way is to engage their disgust. Theirn lies a story in itself.

Next up is China for its investment in biogas digesters, a decentralized in-home system that makes methane for cooking and nutrients to put back into the soil. China has a long history of using night soil on fields and thus insuring the fertility of their fields for centuries. Lots of possibilities for innovation here.

She also includes a slight diversion to tell the story of a pair of inventors on two continents creating a hand pump for collecting privy contents by motorbike. A possible business opportunity in Tanzania.

And on our side of the planet we must also learn about hazardous sludge being used on fields. And no it is not the processed shit itself that is the biggest problem; it is the load of industrial chemicals added to the wastewater from every imaginable industry from chemical production to morgues that make up 25% of our sewage stream. Talk about the wrongful use of the commons. So many different chemicals that it is impossible to prove that such sludge is causing dramatic health problems for nearby residents. Dumping sludge at sea and in landfills also done and not desirable. By now it becomes clear to the reader that so much is wrong with using clean water as a vehicle for waste which then must be cleaned again. And that many, especially those who source their water from rivers, are drinking that water over and over again.

Back in China we are offered a possible future in a rural village where a urine separating composting system is being tested. Invented by the Norwegians, the Eco-san has a urine separator so the urine is processed separately making the solids easier to compost on site for use in the fields. In the city such compost could be put out for collection along with all our other recyclables. Such would be my ideal vision.

What makes this book such an interesting read is all the colorful characters she meets that have taken up the politically unpopular cause of sanitation plus the complex psychological issues of attempting to change human behavior. How culture and social protocol impacts behavior i.e. how the caste system of India created a population of people, the untouchables, who accept being covered with fecal matter as their lot in life. And to add another layer of complexity on the government and world aid level, how sanitation is discussed and addressed as the poor cousin to the much more sexy issue of clean water. How the connection between clean water and the contamination of water by people lacking sanitation is so rarely addressed as one and the same thing.

I am grateful to Rose George for cramming so much interesting detail and stories into this journey and resisting the urge to pass judgement or rant. She has also apprised me of the levels of denial humans are capable of if they don’t want to admit that something unpleasant is going on. And what I already knew to be the cultural dominance of the flush toilet as the pinnacle of human sanitation she makes clear is so not sustainable that the developing world needs to leapfrog this dinosaur whose infrastructure is now crumbling. There is a glimmer of economic hope in the passing mention of the rising price of nitrogen and phosphorus the two main elements of urine. So I’m thinking surely there would be a business opportunity to collect human urine from the source. A stimulating book of a reality humans have created and not fully addressed.

The Afterlife Of Poop: Behind the Scenes on Composting Toilets

Apart from my tribe of lesbian brothers (who are off-grid cabin enthusiasts) I was not surprised that few of my circle have experienced a composting toilet. When I show pictures of my homemade toilet only then have people wondered how they work. There is a high tech expectation that a composting toilet has some internal ability to disappear what is put in it. And while there are sophisticated ones that reduce the solids to a decomposed form through the use of a hand crank, fan and heater, the collection chamber must still be emptied. 

In a large house the chamber can be under the floor with an access door to the outside. There is no need to address the after life of poop for a year or so at which point it is no longer poop. But in a tiny house on wheels the process is much more intimate. In a homemade bucket toilet such as mine, my poop (and all my friends' should they gift me with a deposit) is with me for a week to a month lying quietly in a bed of sawdust and toilet paper. I admit that even I had some qualms about this fact. It felt like hoarding of the most extreme variety. And I must quickly avert my mind to the value of engaging in this cycle of nature that turns digested waste into soil and in turn to food again. And the comforting thought that humans carry all the essential minerals in bodily excreta to create soil to grow food that then provides us with essential minerals. This means we carry with us the ability to bring back fertility to a depleted planet. (This life saving factor aptly demonstrated in the movie The Martian.) How wondrous is that? What a complete package we humans are.

Thankfully the poop removal job has been made virtually odorless by the separation of solids from liquids. Modern composting toilets have caught on to this factor. So there are two containers to empty and process, one for liquids and one for solids. The urine being enclosed in a container with a screw top is easily carried out. Some toilets even divert the urine to a container outside for ease of emptying. 

Urine being rich in nitrogen and phosphorous and having the benefit of being sterile is immediately useful for fertilizing plants. It must first be diluted with water at least 3 to 1 or it will burn the plant. From my workshop at an eco farm I learned that if mixed with a cup of sugar or molasses, diluted urine is made more accessible to plants. Urine can also be added to the compost pile which would help to keep it moist while the nitrogen and phosphorous is preserved in the resulting compost. Seen here is a urine toilet I visited recently at an eco village that used sawdust to absorb the liquid which was then dumped into a compost heap.

Then there is the removal of solids. In a homemade toilet this consists of removing the bucket inside the toilet and taking it to a dedicated compost container in your backyard. (You can also line the bucket with a plastic bag and pitch it, bag and all, in your garbage can as people do everyday with dog poop.) Commercial composting toilets can be more difficult to empty if they have no removable bucket. The one seen on Tiny House Nation called Nature's Head ($960) requires that the whole toilet be unscrewed from the base and taken outside. Granted the hand crank prompts more decomposition and drying and shrinkage before it needs to be emptied so not quite as vivid an experience (but the toilet paper may still be visible). Such details of compost removal is never demonstrated or even mentioned on the show I've noticed. I suspect it would disturb the viewer and scare off advertisers.

A dedicated compost pile or container for humanure composting is the rule. Rest assured that such a compost pile when done correctly will heat up to the high temperatures required to kill off pathogens. It is the size of the pile that determines if it heats up enough. About a cubic yard will do it. Leaving it for a year will also allow for the digestion of any pathogens by microbes, bacteria and earth worms. The weak link of this system is the rinsing out of the bucket. This must be done over the compost pile warns the Humanure Handbook whose author is amusingly verbose in the history and science of humanure composting. (A boiled down 12 page manual is available here.) Lining the bucket with a compostable bag which is then deposited in the compost pile could work too. I was also intrigued by this research paper by the Natural Resources Conservation Service on composting dog poop on a large scale that describes the process in a few pages of concise instruction.

If you cannot face this poop removal lifestyle there are other tiny house toilet systems to consider. For the complete overkill experience there is a toilet called the incinolet for $1849 that zaps the poop to ash with a jolt of high wattage electricity. Or if you like neat packages another toilet called the DryFlush Laveo for $590 plus disposable liners uses diaper pail technology to wrap each deposit in plastic after all the air is squeezed out. Needless to say both these options fall short for the eco minded and frugal.

Humanure composting has entranced me since I first learned about it in the '90s. It made using clean drinking water as a vehicle for transporting poop to a giant central processing plant seem absurd especially considering the difficulty of getting that clean drinking water drinkable in the first place. Plus all the chemicals added to the sewage sludge to render it "safe" before it is trucked out to farms to be laid on fields as fertilizer under the banner of organic matter. (The nerve.) This chemical interference which includes all manner of poisons thrown into sewers (informative blog devoted to the topic here) and rendering our soil ever more harmful and our food less nutritious. The nitrogen leaching out into our waterways has also caused algae blooms that have rendered beautiful lakes and ponds green and dead. A complete fiasco especially considering that depletion of phosphorous in soil is now a world crisis.

And when I learned from my construction technology class how our sewage is processed locally in huge open tanks which can overflow into the bay after a heavy rainfall, the yuck factor made a composting toilet seem much the simpler safer alternative. (Additional tanks can be built to take care of this overflow from processing plants, but I doubt if this has been a priority in our municipality.)

The flush toilet is so much a part of our society that to contemplate using anything but water to flush our poop off site far away seems heretical. When people balk at composting toilets I see how our modern technologies have so obfuscated natural processes that we no longer understand what is actually safe and what our elaborate centralized systems have done to throw nature out of balance. 

Composting was a way to take myself off this land intensive, water wasteful, chemical system and return to a basic, localized mellow process that would improve the very soil around me. In fact my fondness for compost is such that it may have been one of the reasons I have so eagerly embraced the tiny house lifestyle.