Humanure

Before building our house at the farm, it took Dev several months to nail down all the details involved in building a composting toilet for the Indian context. We have been using this composting toilet for over four years now. Here I share the history and details of this construction.

Developing An Understanding

A couple of decades ago, when we were living in California I remember reading somewhere “all of us are peeing and pooping in drinking water”. The blatant truth in this statement hit me really hard. I felt terrible about  what we were doing (or being forced to do). This understanding was weighing me down for sometime and slowly it receded into the background. Several years later I came across this quote by Joseph Jenkins:

“The world is divided into two categories of people: those who shit in their drinking water supplies and those who don’t.”

This was a wake-up call. Dev and I started reading “The Humanure Handbook” by Jenkins. (All the quotes in this article are from this book) Soon after reading this book we decided that we wouldn’t have a septic system in the house that we were planning to construct on the farm. Also, we had a self-imposed limit on the water (2000 liters per day for household and farm purposes) that we could pump from our bore well. We needed to conserve all the water we could and use it for growing trees. Thus a no-flush toilet idea appealed to us right away.

 “According to a composing toilet manufacturer, waterless composing toilets can reduce household water consumption by 150,000 liters per year. This is significant when one considers that only 3% of the Earth’s water is not salt water, and two-thirds of the fresh water is locked up in ice. That means less than one percent of the Earth’s water is available as drinking water. Why shit in it?”

Current Sewage System - A Nightmare

“Let’s assume the whole world adopted the sewage philosophy we have in the United States: defecate into water and then treat the polluted water. What would that scenario be like? Well, for one thing it wouldn’t work. It takes between 1000 and 2000 tons of water at various stages in the process to flush one ton of humanure. In a world of jut 6 billion people producing a conservative estimate of 1.2 million metric tons of human excrement daily, the amount of water required to flush it all would not be obtainable.”

"Our septic systems pollute groundwater; this is an undeniable fact ... Between 820 and 1460 billion gallons of this (water from the sewage systems) contaminated water were discharged per year into our shallowest aquifers. In the US, septic tanks are reported as a source of ground water contamination more than any other source.”

What about wastewater treatment plants or sewage plants?

These plants are basically huge septic tanks that collect excrement(floating in water) of a large population. Treatment plants use aerobic or anaerobic microbial digestion of the solids. Once the microbes do their job and the contents are allowed to settle down, we are left with solids (called sludge) and the waste water. Sludge is treated differently in different places -- benign to out-rightly harmful practices . “The water left behind is treated, usually with Chlorine, and discharged into a stream, river or other body of water.” Whatever happens to groundwater! In India, the fecal sludge is often emptied out into untreated water, agricultural fields or forests. This poses serious risk to the public and the environment.

The Human Nutrient Cycle

 

 

 

PC: The Humanure Handbook, by Joseph Jenkins

I found this excerpt on iharweb.org; it succinctly captures the mess we are in:

“humans are going through the elaborate process of mining and processing to manufacture fertilizers, applying them to crops, and then losing it all via wastewater. Lakes and streams, which receive an excess of nutrients from wastewater are suffering from serious ecological effects such as oxygen depletion and fish-kills. Also, synthetic fertilizer manufacturing is an energy-intensive industry and is expected to increase to feed an ever-growing population”.

Closing The Loop

 “Not all cultures think of human excrement in a negative way. For example, swear-words meaning excrement do not seem to exist in the Chinese language. Traditionally, there was nothing more valuable to a peasant than humanure.”

 "In China, the practice of composting humanure with crop residues has enabled the soil to support high population densities without loss of fertility for more than 4000 years. There certainly was no chemical fertilizer 4000 years ago. The practice of composting all waste (humanure, livestock manure, household organic residues, organic farm residues) yielded a rich manure". 

“Farmers of Forty Centuries” was a book written by Dr. F. H. King and published in 1910. Dr. King was interested in finding out how people could farm the same fields for millennia without destroying their fertility. He writes:

“One of the most remarkable agricultural practices adopted by any civilized people is the centuries long and well nigh universal conservation and utilization of all humanure in China, Korea and Japan, turning it to marvelous account in the maintenance of soil fertility ... mineral fertilizers so extensively employed in modern Western agriculture have been a physical impossibility to all people alike until within very recent years”.

Our Construction

One of our friends, Venetia Ansel, had built a composting toilet on their farm. She helped us understand the issues involved. After a series of discussions at home and some R&D, we arrived at a design that incorporates:

- a urine diverter

- a urinal (for men)

- a urine collecting tank, that receives urine from both the men's urinal and the urine diverter

- a granite-top bench that sits on top of a toilet chamber 

- a toilet chamber 

- an exhaust vent pipe from the chamber

Our Composting Toilet

Composting Toilet Bench

Technical Details:

• The granite-top bench has a "business" area and a wash bowl. The "business" area is basically an opening in the bench with a bucket underneath it. The opening is slightly bigger than a normal Western toilet seat. The height of this bench (38 cm) ensures that it can be used as a Western (sitting style) toilet or Indian (squatting style) toilet. We have a hand-crafted toilet seat, for Western use. 
• The urine diverter, installed in the front of the "business" area, separates urine from the solids. We got this fabricated. This is connected to a five liter can, that is placed outside the building. We dilute the collected urine and use it as a fertilizer. The urine diverter does its job irrespective of the user's position (sitting or squatting). It ensures that the bucket underneath doesn't get  much of the liquid. The user is oblivious of all these technical details. 
• The toilet chamber has an opening from outside the building. We have a metal gate here. We have used an old cycle tube to achieve an air-tight seal (to deter bugs). The floor of this chamber is sufficiently above the ground level, to prevent any water from getting in during heavy rain.
• The vent pipe, from the toilet chamber, is covered with mesh at the top and capped with a PVC 'T' joint
• A hand-crafted, inverted 'U' shaped, wooden platform sits on top of the wash bowl to enable easy washing
• A window with mesh keeps the place well ventilated

Usage

After every potty use, we gently scoot over to the wash bowl and use the health faucet (spray) situated on the wall behind us. To prevent any odour, the (solid) excrement needs to covered well. We use sawdust from the local saw mills as the cover material. We get our sawdust from timber-only mills (these mills don't process plywood). We have used crushed, dried leaves when we couldn't procure sawdust. 

This toilet wastes so little water -- hardly 5 liter, for a family of four for an entire day!

If a composting toilet is managed properly, it should be odour-free...these toilets should provide a suitable alternative to flush toilets for people who want to stop defecting in their drinking water".

Composting and  Pathogens

We do off-site composting. We have a 10 liter bucket, aligned to the center of the opening in the granite-top bench of our toilet. This bucket is placed on a wooden base, with castors. Once the bucket gets filled up, we use a long hook to drag it out of the chamber. We dump this on top of an (unfinished) compost pile. 

We add kitchen waste and farm's green waste to the same pile. We sometimes add the collected urine also, depending on the moisture level of the pile. The nitrogen in the urine balances the carbon in the sawdust. Before re-installing the bucket into the toilet chamber, we wash it and add sawdust to the bottom. This ensures that the contents of the bucket get cleanly dumped. This keeps the bucket fairly clean and uses very little water while washing.

Once the unfinished compost pile gets sufficiently big, we start the composting process. We let the pile cool down for a couple of months. We then use the end product -- dark, fluffy, earthy smelling humus -- to fertilize fruit trees. We have observed that the trees and bamboo close to the humanure compost pile absolutely thrive from the extra nutrition that they receive from this pile. We have not observed the same growth rate anywhere else in the farm.

"There are two primary factors leading to the death of pathogens in humanure. The first is temperature. A compost pile that is properly managed will destroy pathogens with the heat and biological activity it generates. The second factor is time ... Given enough time, the wide biodiversity of microorganisms in the compost will destroy pathogens by the antagonism, competition, consumption and antibiotic inhibitors provided by the beneficial microorganisms".

Feedback from our visitors

We have had visitors from all over India, the U.S. and London. The most common feedback that we have heard so far is "it is just like a normal toilet!" We are very happy to hear this. We have hosted many, many families and have had no problems. A friend who built his house recently remarked "how I wish I visited this place before building my house! I would have built a composting toilet too!" Surprised by the ease-of-use and odourless nature of the toilet, a friend from Bangalore said that she would recommend this design to anyone thinking about such a toilet.

Commercial Composting Toilets

There are many commercial composting toilets now. Eco-san toilets are used in many places in India. Clivus Multtrum USA has been in the market since 1964! BioLet toilets are being engineered and built in Sweden since 1972! "At least 21 different composting toilets were on the market in Norway alone in 1975".

Future

A no-flush movement is gaining momentum in Europe. People are waking up to the fact that the current way of flushing and polluting the environment is not a sustainable one. Just last week, the Sunday Times (UK) ran an article on how "Composting Loo" is becoming the new status symbol!

“we too will have to constructively deal with all of our organic byproducts eventually. We can put it off, but not forever”. 

”... human species must inevitably evolve ... flush toilets and bulging garbage cans represent well entrenched habits that must be rethought and reinvented”. 

-- Hema

 

In Appreciation Of Coconut Fronds

Coconut fronds are easily available in our area. They have many traditional uses -- broomsticks, roof-base for thatch, fuel in wood-burning stoves. We chanced upon this indigenous material while looking for options for unconventional uses at the farm. This post this about those applications.

To keep the house cool, we wanted to block the heat coming in though the windows that were facing east and west. We thought that the window blinds used on the insides won't be as effective as attempting to block the heat on the outside. Commercial outdoor window shades were expensive and were likely to get worn off after a few rains. We finally decided to use coconut fronds for this purpose. We had a pile of woven coconut fronds (keethu) from a previous project. We just tied a few of them in the following fashion and hung this panel off the roof. This thin layer surprisingly blocked off radiation and kept the rooms cool. Yes, it is a chore to hang up the panels in the mornings and take them off in the evenings. But the gains are quite satisfactory.

We have a circular chicken-mesh enclosure that contains the composting material. Our summer heat was drying up the compost pile and preventing it from decomposing well. We tried wrapping an old cotton fabric; it was working only till we had a gust of heavy wind during which this acted as a sail blowing the entire enclosure away. We had to come up with something else. We then planted coconut fronds all around the pile and tied them to the mesh structure. This is working just fine keeping the moisture content inside the pile intact.

In a span of just a few weeks we get a lot of brown leaves in the village. Many trees shed their leaves around the same time. We wanted to harvest this brown matter that could be used later as mulch or composting material. We wanted an inexpensive place to stock up all this bio-mass. Our farm worker Dhanraj built one for us using coconut fronds. He first made panels with the fronds, then tied the panels to the four posts of the enclosure below. One of four sides of this enclosure is operable.

Panel

Mulch enclosure built with frond panels

I noticed that little tree saplings were struggling to survive in the summer heat (42 deg C). The heat here peaks between 2 and 3 p.m. Blocking the afternoon heat became crucial. I planted coconut fronds in a line to do just the job. Three months into this, I know that these little plants have got over the hump. This flimsy, protective heat barrier is giving way, but it has done its job and at no cost! The mulch in the picture below is coconut frond leaflets discarded after broomsticks are made.

I plan to use light-weight frond tips on trellises to create partial-shade condition below for shade loving plants. The beauty of these fronds is that they are entirely local, mostly discarded and zero-cost. If they cease to offer the protection that we are looking for, they simply become part of the soil; there is no waste.

-- Hema

Windows

Modern windows and their construction, both in India and the US, have bothered me quite a bit for the following reasons:

- Window sills, whenever they exist, are on the outside of the building. These sills are rendered useless, collecting dust and debris.
- The placement and height of the windows ensured that we stared at the walls when we sat on the floor and never could enjoy the view, defeating the very purpose of having those windows there.  Since we preferred floor seating, this issue was nagging me constantly.
- Elaborate window grills are maintenance nightmares.
- Windows with glass panes let in heat even when they are closed.
- Window panes are too big; there is no way to open small portions.
- Windows that are flush with the wall seemed to me like incomplete construction.

So I decided to understand windows very well, before we started our house construction.

Our architect Mr. Sudhir, founder of Peoples Architecture Commonweal (www.commonweal.in), specializes in vernacular architecture. He insisted on us visiting many local traditional houses and gaining understanding on how and why things were done the way they were.

On close observation, I realized that the windows in old, traditional style houses in our village differed quite a bit from the ones in new houses and also had addressed many of my concerns. I wrote about these houses here:

http://devandhema.blogspot.com/2017/12/when-beauty-gives-way.html

With aesthetics and utility in mind, I started fervently reading Christopher Alexander’s book “A Pattern Language” and found it to be a great resource in designing our house. Here I illustrate the features of our house that are in line with the patterns in this book.

Most of our windows are 18” from the floor. They are all used; procured from building demolition sites. All our windows have four panes; two top panes and two bottom ones (pattern 239-Small Panes). The panes are solid wood. In some windows, the small non-operable part at the top is glass. Our walls are 15” thick; 50% thicker than normal brick walls (pattern 197-Thick Walls, pattern 223-Deep Reveals). This is because of the outer skin of burnt bricks that is covering the inner adobe bricks. The thickness of the walls  provides ample sill space. In some places we have extended this sill space to achieve window seating (pattern 202-Built-in Seats). Christopher Alexander says:  "windows that create “places” next to them are not simply luxurious, they are necessary" (pattern 180-Window Places).

A built-in bench by the window in the living area

A built-in bench by the window, connecting kitchen and dining spaces

A built-in window seat

This built-in bench merges with the window sill

Kitchen Window

The kitchen window sill merges with the counter

From Christopher Alexander’s book, I learned that not all windows have to be of the same size. Also, in some places it is not appropriate to have big windows. This was the case in our corridor connecting the two rooms. We have a small window here offering a glimpse of the easterly view,  as in pattern 134-Zen View. 

I enjoy these window places so very much.

-- Hema

Our House At The Farm

Main Entrance

Living Room and Kitchen

A bedroom on either side of a thin, long corridor

Window Seat

Attic

Compost Toilet

Vegetable bed at the back

Our chickens, Rakhi and Vellam, in a pen

Raja's Tree

Raja and his brother live on the same street as us. Their parents are weavers who work on power looms. Typically weavers here have one or two power looms installed in their houses. It is a distributed factory setup. The woven fabric, lungis, are picked up by middlemen and sold to agents further up the chain. A vast majority of these weavers are illiterate. They get the looms installed by borrowing a big lump sum.  They make about Rs. 8000 per month for their labour.

The traditional house design for the weaving community involved one or two courtyards and rooms on the front and back of the courtyard(s). These wall to wall houses used to have a pitched roof covered with country tiles. The new settlements however are devoid of these features. The weavers live in houses built with bricks or cement blocks with an asbestos sheet roof. It seems to me that their houses are built to house the looms. There hasn’t been much thought to make the houses more livable for their human inhabitants. 

Raja’s parents moved in to this neighbourhood six years ago. They accidentally planted a Pongamia tree in front of their house. It is right next to their only water source. This tree is a part of their everyday lives as in the pictures below:

Enjoying the tree's shade with friends and relatives

Up a tree-house made with sticks

The mom washes clothes and the dishes under the tree

Putting the baby to sleep

Parking, socializing and also retiring (when they bring their cot out here)

This tree has been an indispensable extension of their house, moderating temperature even when it was blazing 110 deg hot. Really wish there were more trees in all our neighbourhoods.

-- Hema

A Parallel Construction

When we started our farm house construction, the kids used to hang out at the site. They were then 13 and 10. A few months into the project, Abhi decided to build something on his own. Aparna soon joined him. We came to know about this when left over material from the house site was getting hauled to a corner, not too far away. Working on and off, it took them eight months, from conception to completion, to build a room that is about 25 sq. ft. 

The kids provided the following details about this process:

Foundation:

They dug a foundation trench that was about 1’ wide and 1’ deep. As the soil was quite hard, this digging took about a week. They filled the trench random rubble and mud mortar. The rubble layer was raised above the ground by 6”.

Assessing the use of an abandoned section of a pillar

Plinth:

Some temporary masonry structures were lying abandoned near the house construction site. The kids made use of these pieces to construct a 9” band on top of the foundation.

Walls:

About half of the bricks that were used in our farm house were sun-dried adobe bricks. We got them made on site and they were one-third the price of burnt bricks. The kids decided to use the left over adobe bricks and mud mortar for their project. The walls are less than 6’ tall and 9” wide. Protecting these (mud) walls from rain was their biggest problem. Everyday, after work, they had to drape the structure with water-proof tarps.

Maintaining plumb

Checking the doorway

Window/Door:

The entrance is actually at the back. That’s how Abhi wanted it to be. He built a window frame when the walls were tall enough to have an opening. 

Roof: 

Once the walls were completed, there was a long period of inactivity. During this time, there were discussions about the kind of roof they wanted to do and apprehensions about taking it up. While our carpenter's team came to work on the farm house's traditional roof, the kids decided to resume their work. There was plenty of left over timber of odd shapes and sizes to play with. They consulted the lead carpenter for technical details. The roof was built on the ground by constructing a pyramid first. It sat on a stack of bricks. Once the roof was ready, they needed help to mount it on their walls. This was the only time they asked for help from us.

Securing purlins to the rafters

Time to admire the roof

Once the roof framework was in place, mats made of woven coconut fronds (keethu) were tied to it. Abhi sat on the roof and tied the keethu to the purlins that Aparna was handing him from inside the room. They swapped roles when they felt like it. 

The roof work took several weeks. Once this was completed, they once again started enjoying the rains without any worry.

A picture of the roof taken from inside the room

Plaster:

They were by now familiar with mud plastering, from watching the masons at work on the farm house. Sieving the soil, preparing the mix a day in advance, plastering a wall, cleaning up the tools was their day routine then. Inside and outside put together, there were eight sides to be plastered and two levels of plastering to be done, first rough then smooth.

Finish: 

They applied diluted lime wash (aka white wash). Lime protects the exposed walls from the rain. This was applied in six thin coats, one coat a day.

First coat of very dilute white wash

Floor:

On a leveled substrate of soil mix, terracotta clay tiles were placed with 1 cm gap between them. The gap was later filled with a homemade grout mix that contained finely sieved sand and cement.

Shelves/Niches:

This little space has five storage compartments each one with a flavour of its own.

Visitors from the neighbourhood