First some numbers about human waste:
- one billion practice open defecation(Katko and Hukka 2015)
- 2.5 billion people are without waste water treatment or sanitation (Katko and Hukka 2015)
- "Future water and sanitation services will face several challenges in the future: ageing infrastructure and increasing staff retirement particularly in the North, and deteriorating systems and inadequate service levels and management skills in the South. In fact, ageing infrastructure is likely to be the biggest challenge worldwide in the coming decades" (Katko and Hukka 2015)
|Although this is actually a funerary monument in Petra- It seems like we need to put our wastes front and centre in our minds instead of just flushing away our problems.|
Composting Toilets as an Appropriate Solution:
There are many different ways to process our wastes. Composting toilets are only one way. There are also interesting innovations in living wetland waste systems, otherwise know as living machines. Just like any problem, we look at a variety of factors before arriving at a solution. For example, for treatment of human wastes we might consider the following: the people using the system, the skills required to use and operate the system, scalability, installation cost, operating cost, ongoing maintenance requirements, performance of a system over time, water use, use of chemicals, ability to effectively treat pathogens, energy requirements and what legal, and social context we are operating in.
From a simplistic look at treatment our wastes, composting toilets are appealing because they do not use water, they do not need high energy inputs, they produce a valuable, nutrient rich end product, they can be low cost, and relatively low maintenance. David Holmgren wrote this beautiful summary of how composting toilets follow and embody permaculture principles.
|This cabin in Hawaii National Park has a most excellent commercially built composting toilet by Phoenix|
In addition to the practical applications of composting toilets, there is also the philosophical aspect of taking responsibility for literally, your own shit. Joseph Jenkins in his book The Humanure Handbook, talks about a group of nuns, the Sisters of Humility. The Sisters of Humility explained that they were interested in composting toilets because "The words 'humble' and 'humus' come from the same semantic root, which means 'earth'. We also think these words are related to the word 'human'. Therefore, as part of our vow of humility, we work with the earth." (pg 70, The Humanure Handbook)
|Entrance to a two chamber composting toilet at Gardens for Health, Rwanda|
Jenkins says :"The exercising of the human spirit can take many forms, and the simple act of cleaning up after oneself is one of them. The careless dumping of waste out into the world is a self-centred act of arrogance- or ignorance." (pg 70 The Humanure Handbook).
How Composting Toilets Work:There are legitimate concerns about human waste, pathogens, disease and parasites. There are also legitimate concerns in how our wastes are currently being treated (or not being treated depending on the case), and closing the nutrient cycle loop. For most of us who grew up with toilets that flushed everything away, it is a big step from flushing to composting.
Composting toilets kill pathogens by creating an environment for hot, aerobic biological composting to occur. This means that composting toilets are typically designed with moisture, oxygen, size, carbon to nitrogen ratio, pH, and time length of containment in mind. The end product of a properly designed and maintained composting should look and smell like a humus rich soil.
Soil, an organization that provides safe sanitation options in Haiti through composting toilets, as well as a much needed fertilizer for the depleted soils, has documented the effectiveness of properly designed and maintained composting toilets to kill pathogens.
Problems occur when raw manure come into contact with water, bugs/critters, soil, and end up back to us. These are the things that you want to avoid in designing your composting toilet situation. Otherwise, there are numerous designs out there from commercial systems to DIY.
|Foot pedal hand washing station outside the composting toilet, Gardens for Health, Rwanda|
Some basic guidelines:
- Poo should not come in contact with surface of soil, surface of the water and the ground water.
- Poo should not be accessible to pests, bugs on people. (lid is down, fly screens etc).
- There should be no bad odours or unsightly conditions. You need it to be contained and properly composted! (ie areobic composting conditions, thermophilic conditions are best, at least 50C)
- It should be simple. (you should not touch it too much, and make it as easy to use as possible).
- Construction must be durable. Easy to maintain.
Composting Toilet Options:
In The Humanure Handbook, Jenkins goes through many designs of composting toilets, but his favourite, and one of the simplest is the 5 gallon bucket and a compost pile. Surprisingly, all it takes is a box or something to put a toilet seat on the fits the 5 gallon bucket, some sawdust or other carbon rich material and a well tended hot compost pile, with lots of hay/straw/leaves to cover. For further instructions, pictures and videos: http://humanurehandbook.com/
|5 gallon bucket with some sawdust to cover and to increase the C:N ratio|
Most people have probably seen the two bin cement bin system where you fill cement compost bin that is under the toilet and then once it gets full, switch over to the other side. This gives one side time to compost and rest for a year or two before taking out the compost. This is the most common system I have seen in homes, parks and eco-villages.
|Two-bin composting toilet at Channel Rock, Cortes Island, BC|
Other people have made compost bins out of barrels, or wheely bins as a batch system that they let rest after it's full. This is appropriate for people who don't want the weekly chore of emptying a 5 gallon bucket and don't have the resources or space to build a 2 bin cement composting toilet.
|Bin compost system on Cortes Island, BC. The bin is change out and left to mature for 1-2 years after it is filled.|
The outhouse to tree system is also one option- although it is not truly a composting toilet system. This is where you dig a hole for an outhouse, use it like a normal outhouse, except you add carbon rich (sawdust) materials after each deposit. When it starts to become full, put soil on top and plant a tree on it. This is also known as the ArborLoo and is featured in this pdf of composting toilets in Zimbabawe. Although this is a great strategy to expand fertility of an area and for planting trees, this type of toilet still has the downfalls of an outhouse/pit latrine in that if you have a high water table and sandy soils, there is risk of contaminating your water supply.
I have used many composting toilets, and I can say that hands down they are 100% nicer that most outhouses (which are smelly and fly infested), and can be just as nice, if not nicer that flush toilets. Jack liked the ones in Hawaii National Park so much he blogged about them.
|How to provide sanitation systems for growing populations, with limited water? Kigali, Rwanda|
Wherever you are at, find the leverage points for closing the loops and living a more vibrant life with earth and people. If it is making a composting toilet- great. If it is going to the farmers market- great. If it is taking the bus instead of driving-great. We all have places where we can work, and share what is working with our friends, family and communities.
By composting humanure our "....excretions are humbly collected, fed to microogranisms and returned to the Earth as healing medicine for the soil." (pg 70 The Humanure Handbook)