How to Create a Compost or Dry Toilet

How to process your humanure

Humanure

Here is a link to the Humanure handbook, I haven’t finished it, but it’s a good read, and really gives a great in-depth understanding of how to compost human waste … and the history behind sewage systems, alternatives, etc … and the importance of putting humanure back into the earth

For your compost toilet you need two parts:

  • The toilet
  • The processing/composting system

For both of these there are multiple options, and each have their pros and cons, and will suit people differently.

The Toilet

There are multiple options,

  • a simple mobile solution that you put inside your home that you empty regularly;
  • a solution that you build into your house or outhouse which feeds into a large chamber (that is essentially outside)

It’s obviously a bit more involved to build a toilet with chamber, but once it’s in it’s the most low maintenance you will get in terms of a system.

Here is a sketch for your reference if you wanted to build one yourself

Vermicast Toilet Pit Solution

‘Portable’ compost toilet solutions

There are two routes to go with this

  • urine separation
  • all in one bucket

There are various systems that separate urine, the reason for this is we pee way more than we poo … so the bucket will fill much quicker with urine … and the smell can be intense if not sufficiently covered and absorbed with something like saw dust, which means creating a larger amount of matter to be decomposed, and more regular emptying. Also drier (not dry) faecal matter will reduce in quantity quicker in the breakdown process, with even less of a chance of smell. Below are some different options:

  • A two bucket system (one for urine and one toilet for faeces)
Double bucket compost toilet
Compost toilet with urine separator
  • a urine separator in one system (this seem quite good in idea, especially for small spaces and a larger number of people using the toilet, – as most of what people create will be pee, so the solids bucket won’t need emptying as often. The pee container will probably still need to be emptied daily, or the smell will still become strong … I also wonder whether the smell on the urine separator will remain present. There will need to be careful aim though not to mess into the wrong chamber, and boys need to sit to wee.
  • a one bucket system – urine and faeces go into one bucket
    • Here’s a guide to make your own: http://humanurehandbook.com/humanure_toilet.html
      There are also lots of people making them at the moment, so you could also just order yourself one. Everyone I’ve seen is using the humanure design, personally I’ve gone for something a bit different  – because, although it looks nicer to have the bucket underneath the box, and the toilet seat directly on the box, there is room for spillage and mess … so I have my bucket coming out the top of the box, and the toilet seat on top of that with a raised hinge at the back, that way there is no room for messing. It’s only marginally less attractive than the alternative, but it’s a more sanitary solution. It also means quick access for opening and closing the bucket lid in between each usage (as I prefer to keep the bucket lid sealed when not in use, to keep any smell and potential pathogens contained). Below are pics of mine in the making …
Dry compost toilet
Dry compost toilet
Dry compost toilet
Dry compost toilet

Cover Material

Saw dust is great cover material as it absorbs the urine, and fully ‘seals’ the faeces so it doesn’t release a smell. Adding lots of saw dust means creating a greater amount that you needs decomposing, so I’m putting a thick layer of straw on the bottom of my clean bucket, then using saw dust as a cover material thereafter. The straw will allow some space for liquid build up; it will prevent anything sticking to the bottom – which will make it easier to clean (especially important during water scarce times); and the straw will assist with oxygen flow between each layer of each bucket of waste when on the compost pile. Other matter such as dried leaves, shredded paper, etc can also be used. I get my cover material from Animal Feeds in Fish Eagle Park – Kommetjie. It’s R60 a bail of hay, and R85 for a large bag of untreated saw dust.

Emptying the toilet

If you have a larger family, you can have multiple buckets, so you’re not having to go to the compost heap as regularly – if buckets are all the same size, when the bucket fills, seal the lid, put to one side and swap with another bucket … then take all buckets to the compost heap once a week, empty, rinse, and return them to the bathroom ready for use.

Processing

There are various options to go with. If you have an open system, ensure you keep it well clear of any water sources and that you don’t have a high water table, if it is draining into the earth. If it is draining into the earth, look at where it’s placed and consider whether it will drain easily or needs to be placed on gravel, or some sort of drainage area.

Composting

This is the processing system used in the humanure book and how people most commonly compost their humanure. Create a compost heap, with your organic waste which includes your humanure. It needs to sit in the heap for a year, and then after that is good to use to feed your garden. Don’t use it on veg gardens, but anywhere else – trees, shrubs, lawn, etc
Ensure there is sufficient:

  • oxygen in your compost pile, so perhaps put straw in between, so it doesn’t compact too much with the saw dust (this will also cover it so it’s not exposed)
  • moisture – it needs to be a moist environment, if you are pouring the urine on the compost heap, this will be plenty

Heat is created when organic matter breaks down during the natural processing of composting, and this is what kills the pathogens
Once your pile is full, let it sit for a year to fully break down, and create a second pile that you use … and rotate annually between the two piles.

faecal matter processing

An alternative to using a standard compost pile system, is using a drum with aeration holes:

  • If your faeces is separated – put just your faeces in the drum, and when rinsing the toilet bucket pour the water over the top so it doesn’t dry out to much, it will dry out to a point though which greatly shrinks down the amount of waste. My boyfriend uses this system and a bucket takes about a year to fill per person.
  • Urine can be added to this (ensure there are also drainage holes out the bottom), alternatively if separated, urine can be added to your compost pile or mixed with water and fed to your garden.

This is a useful guide out of the Humanure book

Do's and don'ts of Thermophilic Composting for human waste

Worm Farm

I’m experimenting with this route, worms are incredible at breaking down toxins. I created this video with African Earth Rights on the Green Guerrillas, it gives a little insight into why worms are so awesome.

I have a ‘Worm Hive’ from the pole yard, here’s the link. What’s great about this, is as matter breaks down, I can extract the vermicast from the bottom, so it can continue to be filled from the top, and emptied from the bottom.

I’ve purchased worms from the Green Geurillas, and some from Soil for Life … so I could have enough to get going with straight away. Green Geurillas sell it in a plug and play solution – as they come in a bag of soil, with cocoons, for R800 per kg, Soil for Life sell the worms for a tub at R50. Buying worms straight with no soil, you will need to give them time to make home and settle, before starting to work with them as a farm. Both these places are wonderful sources of knowledge and information.

It’s not hard work, but a bit more attention is needed when worm farming, to make sure your worms are alive and well and conditions are right. Give your worms time to settle when you first set up your worm farm, watch them for a bit, and feed them gently at first and just make sure they’re established and happy before starting to use it as a humanure system.

If going with a worm farm, and you’re not separating liquids and solids, be sure that excess liquid can also drain out, you don’t want to drown your worms.

Below is some info on worm farming:

  • Worms eat the same as their own body weight in 24 hours. It’s said people produce 200grams feaces a day, so Oxfam are saying 2.5 kgs of worms could cover a family of 10.
  • Worms double every 55 days, so if you put 2,5kgs worms in, after 2 months, there would be 5kgs. They will only grow to the size of the space they are in though – this is based on the area not the height. (Apparently the Worm Hive stores around 4-5kg of Worms.)
  • Worms need 80% moisture and plenty of oxygen
  • Preferable temperature is around 22º – if it gets too hot, they will die, too cold and they become dormant. (If it gets very hot with composting material, they will move back down and stay below where it is cooler. But it does mean the container should be kept in a cooler and shaded environment, and built in a way that it doesn’t overheat)
  • They need a mix of green and browns (carbon & nitrogen – carbon would be the browns – so straw/saw dust/dried leaves etc; nitrogen is the greens, veg off cuts, freshly cut grass, urine & faeces)
  • Worms don’t have teeth, so it’s good to shred material at first
  • For compost toilets, straw is good, saw dust will take longer to break down and is more compact which means less air. If it gets too compact – add some air by shifting things around with a fork. Shredded paper is also good. Lots of people recommend newspaper, I worry about the ink. Some have said they are fine with the ink, and that it’s a way to ‘neutralise’ it…

Bokashi

Bokashi systems causes compost to break down at a much quicker rate, and also works anaerobically (without oxygen). So in this system you would have an airtight container, throw your organic matter in, put cover with bokashi bran and seal. You can add any organic matter, from veg, to dog poo, humanure, cooked food, meat, etc. For my kitchen organic waste, I fill a bucket once a month, let it sit for a month, and then bury it. While it’s sitting, I have a second bucket that I am using, which I rotate. If using this system for humanure, I would definitely let it sit for much longer (possibly for a year) to ensure all pathogens and any possibility of worms were killed off before burying.

With the micro organisms acting in the bokashi though, it will (like the worm farm) be extra efficient at processing toxins, at a much faster rate.

The Bokashi system would be best used with a system that separates urine, so that you don’t collect too much liquid in it – you don’t want the bucket swimming in liquid.

Something like this sealable drum would work. You would need at least two drums (so you can rotate them while one sits), and definitely more for a family, as it will fill up quicker.

Normally in a bokashi bin, you would have a grid that lifted the solid waste from the bottom, so that liquid can all drain below and it doesn’t sit in the liquid, going rancid…. so either cut a grid of some sort of sieve that can fit into the bottom and then raise the grid it so it’s not sitting right on the bottom, to keep a drainage system, or put a bed of sticks and straw on the bottom.

I’m chatting to a couple people at the moment about making larger batches of bokashi … it can be made quite simply at home, but you can also purchase it at Organic Zone / Soil for Life / various health shops / Faithful to Nature

Oxfam using Tiger worms in dry toilets:

By | 2018-02-03T12:11:45+00:00 January 26th, 2018|Lifestyle, Sustainability|1 Comment

About the Author:

Natalie has a passion for healthy and circular living, and is always exploring spaces where she can learn from people with expansive knowledge. With a background in graphic/web design and film, she uses these communication skills to share the valuable knowledge she encounters. Following 10 years in London, feeling the disconnection of society on so many levels, she explored the more alternative lifestyle communities in Wales and France, and then spent a year in a camper van travelling around Australia, living in the bush and visiting eco villages, learning about health, nutrition and regenerative/natural living. She has since returned to her home country, South Africa, where she works in multimedia and communication with projects that focus on a healthy world. Some of these include African Earth Rights (Love local, love sustainable); Soil for Life (who teach organic gardening, and wellbeing in impoverished areas); Good Life Organics (suppliers of organic products); Wild and Waste Free (Packaging free, community focused shop); TAGDit (social media app for deep democracy and information sharing within groups); PHA Campaign (Protecting Cape Town's primary food growing area).

One Comment

  1. Anna Varney-Wong January 26, 2018 at 5:01 pm - Reply

    Brilliant you awesome gal!

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