We started construction of compost toilet in May 2019 and completed in August, the same year. The compost toilet foundation and the chamber walls, the chamber ceiling were constructed with stones, hollow bricks, cement, sand and concrete. The walls were built with self-manufactured sun-dried adobe bricks made with farm sub-soil. The roof was a madras terrace roof. The walls were built by volunteers Deepak, Sohn, Noushadya and I invited and hosted from all over the country. Check out our past blogs about the compost toilet :
Volunteers, guests, Noushadya and I started using it right away in 2019. After every deposit of poop, we were putting more than 3 handfuls of either dry leaves, saw dust or ash in the chamber. Ash was added once in a while to avoid any stench. The first chamber got filled by August 2020, in one year. We moved into our Earth house in the end of August and then started using the flush toilets in the house.
We started using the second chamber in September 2020. It took 16 months for this chamber to get filled. But, from December 2021 to April 2021, we didn’t move back to the first chamber because Noushadya and I were mostly out of station.
And i got the opportunity to empty the first chamber today. It had been 20 months since we had last used it. When I opened the chamber, it didn’t have any stench in it. I was expecting a compost like material. But there was no petrichor-like smell in the compost pile whatsoever.
There was obviously no feeling of handling poop. This is where the strongest inhibition of using a Compost Toilet lies with people, because the way poop has been handled by backward castes was extremely exploitative and shameful.
Carbon to Nitrogen ratio
It was a rainy, cloudy morning thankfully and the work was easy. I used a shovel, spade and a fork to loosen up and empty the chamber. It took less than half an hour. It is important to keep in handy a tool with a handle length as much as that of the composting chamber’s length. As soon as I started removing the organic matter, I realised that the matter was full of carbon rich material only. The nitrogen in the poop had gotten composted and come to equilibrium with its surroundings. But there was a lot of saw dust, hay, dry mango & neem leaves, that hadn’t gotten composted. To cover up the poop, after every deposit, we used up too much saw dust. The excess carbon in the pile didn’t have any nitrogen to compost.
A aerobically well-composted pile needs to have an ideal carbon nitogen ratio of 30:1 for it to be in a form that plants can assimilate. Saw dust is extremely rich in carbon. If it is used as mulch directly on tropical soils, it will draw all the nitrogen in the soil to itself and leave plants deficient of this critifcal resource. It has a carbon to nitrogen ratio of 300-500:1. Ash also doesn’t seem to have played any role in the pile – Wood ash has very little carbon. Dry leaves have a carbon to nitrogen ratio of 30-50:1, which is more closer to the ideal compost ratio and should have been used in abundance. So, the biggest learning from this activity is to use dry leaves, hay and other crop waste in the farm which isn’t as carbon rich.
How do I correct the C/N ratio in the compost pile
Now, the pile that I have is very rich in carbon. I will have to add a lot of nitrogen rich material to compost it. I will make a new pile along with nitrogen-rich cow-dung and the carbon rich human waste compost in layers. I will turn the pile and water it once every week and I should have finished compost in another 2 month’s time. This will ensure that the temperature of the pile should go up to 60 degrees in the next 1.5 months and destroy whatever pathogens might have been left over.
If there was stench in the pile, it would have meant that the pile is very rich in nitrogen. However, this is unlikely to happen because, while in use, if the stench would have occurred, toilet’s users would have ended up adding more carbon rich material.
“Education is the most powerful weapon you can use to change the world.”Nelson Mandela.
I had no inhibitions in working with composted poop because I had used compost toilets in Auroville while volunteering at Solitude Farm & Kitchen and AuroOrchard. I also read a book called Humanure to gather exhaustive knowledge and to understand the sensitivities around the topic of composting. I also gathered a lot of information from people who have built dry toilets around the world and had published blogs & articles online. I am thankful to all of these people!
Despite all of this knowledge gathering, we ended up making mistakes in implementation and learnt from it to take corrective actions. So…
Experience is the best teacher.A truth spoken by a lot of people across time because it is an obvious conclusion. Haha!
One of the major deficiencies with sustainable agriculture is that phosphorus isn’t easily available . Phosphorus is a macro nutrient which cannot be ignored. Phosphorus is concentrated in grains, seeds, bones, nails, beaks, horns etc. So, unless we compost humanity’s poop and recover phosphorus from bodies of domesticated animals that die, we will be wasting a lot of phosphorus.
Much is said about how efficient industrial large technologies are. But, can there be anything more efficient than this toilet, where local resources are used to produce wealth out of waste and uses very little fresh water. We only need to get rid of our stigma of handling poop. And we need to accept that there is no way out of the mess that industrialization civilization has gotten us into than building circular systems in every aspect of our lives!
Write to us in comments below about how would you feel about using a Urine Diverting Dry Toilet such as this one.
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