Eating is an agricultural act - Wendell Berry

Saturday, July 10, 2010

composting human waste - humanure

5 months ago, i wrote about the sanitation at pR - a reasonably debated post.

since then, we used the ecopan system (stage 2 in the above post) for exactly 37 days till one vault had filled up (early may). it was an volume estimation error; we had anticipated that one vault (approx 2 cubic feet) would last for around 4-6 months.

while we hit a roadblock on moving to the ecosan toilet (stage 3 in the above post), we reverted to the 2 pit system (stage 1 in the above post).
we thought that during the peak summer, there was a much lower risk of ground water contamination. of course, it was irking that we took a step back rather than forward. but like all experimenters, we are prepared for a bit of back and forth.

so when one is in deep shit over shit, one goes to the god of shit - aka joseph jenkins - the humanure guru (DV has just posted on this at
his epic book - the humanure handbook - is just that, an epic. and free to download.

this is how he starts...
There is a disturbing theory about the human species that has begun to take on an alarming level of reality. It seems that the behavior of the human race is displaying uncanny parallels to the behavior of pathogenic, or disease-causing, organisms.
When viewed at the next quantum level of perspective, from which the Earth is seen as an organism and humans are seen as microorganisms, the human species looks like a menace to the planet. In fact, the human race is looking a lot like a disease — comprised of organisms excessively multiplying, mindlessly consuming, and generating waste with little regard for the health and well-being of its host — planet Earth.
and so he goes on to brilliantly compare human behaviour with pathogens in chapter 1. but before one yawns off to say that he is being overly sarcastic, he ends with a hopeful prediction...
...we will destroy neither the Earth nor ourselves. Instead, we will learn to live in a symbiotic relationship with our planet. To put it simply, the human species has reached a fork in the road of its evolution. We can continue to follow the way of disease-causing pathogens, or we can chart a new course as dependent and respectful inhabitants on this galactic speck of dust we call Earth. The former requires only an ego-centric lack of concern for anything but ourselves, living as if there will be no future human generations. The latter, on the other hand, requires an awareness of ourselves as a dependent part of a Greater Being. This may require a hefty dose of humility, which we can either muster up ourselves, or wait until it’s meted out to us, however tragically, by the greater world around us. Either way, time is running out.
and he beautifully mixes up history, science, philosophy, economics to lay bare the simple ways to convert human waste to manure.

ok then, the jenkins rah-rah is over now. back to the ecopan at pR.
as per his estimates the human faeces will compost completely within 47 days in a urine diverting toilet system (where there is no water mixing with the human waste)
and yesterday, we were around 60 days since sealing off the first ecopan vault. and 60 days of composting in the hot summer is surely enough.
so we went ahead and opened the vault. poked it around a bit.
and it looked like this.

we used a combination of sawdust, ash and dried leaves (just a handful) to cover the poop each time.

and we dug right in...

it smelt like compost, it looked like compost, it IS ready-to-use fertiliser.

jenkins' comparative data comparing different type of manure is below.
Manure %Moisture %N %Phos %K
Human 66-80 5-7 3-5.4 1.0-2.5
Cattle 80 1.67 1.11 0.56
Horse 75 2.29 1.25 1.38
Sheep 68 3.75 1.87 1.25
Pig 82 3.75 1.87 1.25
Hen 56 6.27 5.92 3.27
Pigeon 52 5.68 5.74 3.23
(would appreciate table making tips on blogger via email).

after bird shit (guano), humanure is superb as a fertiliser.
we agree. am sure that our fruits and vegetables will too.

humans are the geese that are laying golden poop. can we afford to flush it in nothingness?
in search of answers to these type of questions is what led us to move to pR. along with, of course, the morality of career choices and such-like.


Kishore said...

This obviously is a huge problem, robbing the population of huge amounts of potable water, spreading disease etc.

What are your thoughts about how this can be applied to larger scale?

I wonder where the gaps between the available knowledge and application are?

Look forward to your thoughts.

csm said...

there are so many simple systems to start this process either at a colony level/office complex level.

i did a few elementary google searches and found tons of relevant links. there are many solutions and companies which offer large scale solutions.

the big gap is (as always) in the mind. it is Shit after all! (yucK)