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Talking Sh*t (Compost Toilets)

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Waste Management: Getting down and (not) dirty with dry toilets, composting toilets, dehydrating toilets, humanure, soak aways – closing the loop on bio-waste.

(Full disclosure, I’ve been waiting all week to write my punny title for this post. I know, I know…)

Intro: Why Compost Toilets?

In Talking Sh1t, we’re looking at eco friendly, sustainable ways to handle sewerage when living off grid.

We’re going with the compost toilet system, and in this article you can find out more about them. As well as why they’re such a great option!

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We are on a journey to living off grid and self sustainably in South Africa.

Along the way, we’re doing a lot of research into various topics involved in this lifestyle.

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Compost Toilets: Myth Busting

  1. Compost toilets, used correctly, do not stink or have flies.
  2. They are actually very easy and affordable to set up.
  3. The waste can be composted by following a few simple guidelines.
  4. They are safe, sanitary and clean.
  5. They can be used indoors, in your bathroom, just like a water toilet.
  6. Like a water system, you can only put biodegradable matter into it. Like toilet paper, biodegradable/cotton tampons etc. But not disposable nappies, pads or anything containing plastic / non-biodegradable items.

Some examples of two well known commercial compost toilet brands – Sun Mar and Nature’s Head. Tiny house-ers and mobile home-ers in the USA often refer to these brands.

Benefits of a Compost Toilet

To me, choosing a compost toilet over a water toilet is one of the best and easiest choices you can make if you want to go green.

Waste shouldn’t be put in water – it should go back to the earth, as per the natural cycle.

Instead of flushing it away, you could be feeding your soil with well-composted manure, enriching it and replenishing it.

People can be a little skittish about composting toilets, but really, there’s no mystery – and you can choose a set up to custom suit your needs!

I’ll chat about the system I’ve chosen to go with, and how I arrived there, in this post.

The image here is of the beautiful wood compost toilet I ordered from Sylvantutch in Knysna (they deliver).

Sylvantutch Wood Compost Toilet

The Basic Box

A compost toilet can be as simple as a toilet lid over a bucket.

The two main criteria are:

  1. The lid must be firmly attached to the container (i.e. no gaps) so as to block out flies and other critters, and
  2. You have a suitable organic matter to cover your waste after each use.

Organic Matter To Cover Your Waste

The most common and effective covering used is wood shavings.

But I’ve heard of people using various other organic substances you can try too:

  • Sawdust (may not be as effective as wood shavings in airflow allowance)
  • Dried grass cuttings (may not be as effective as wood shavings in airflow allowance)
  • Dry leaves (not always available)
  • Sand (beware the weight accumulation)

One or two scoops of sawdust is usually sufficient – all you need to do is make sure the waste is covered. Its ok if a bit of toilet paper peeks through.

Compost toilet with wood shavings

What Happens When The Bucket Is Full

Once the bucket is full, take it out of the toilet. Put on a lid punctured with some air holes to allow for evaporation, keeping the holes small enough to prevent critters from sneaking in.

Set it aside out of direct sunlight and sheltered from the rain to continue composting, and put an empty bucket under the toilet seat.

As a rule of thumb, have a full bucket sit to decompose for 6 months or more.

When it’s sufficiently broken down you can empty the bucket into your usual compost pile to be used around trees etc.

You can tell it’s sufficiently broken down as you shouldn’t be able to see any toilet paper or solid matter remaining, it should all be broken down.

Once it’s emptied, you can use it again in the toilet.

How many buckets you need depends on how many people are using it and how frequently, so you should be prepared to buy a few extra buckets in for the first few months until you reach the right amount.

Solvey Compost Toilet with bucket and wood shavings
Solvey in Cape Town offer a compost toilet, buckets and wood shavings.

Compost Toilet With Urine Splitter

Going one step further from the basic box compost toilet, you can add a urine splitter.

A “urine splitter” is a funnel that fits over the front half of your toilet, channeling the liquid one way while the solids drop straight down.

We sourced a urine splitter from Sylvantutch – the splitter is an optional extra.

Compost toilet with urine splitter diagram
Image from www.ecovita.com

Advantages Of A Urine Splitter In A Compost Toilet

Splitting the urine from the solid waste has some great advantages.

1. Reduced Mass

Firstly, since human waste is 90% water, by separating your urine output from your solid waste output, it takes a lot longer to fill up your bucket.

Its worth noting that urine, being high in nitrogen, does speed up the composting process – its a great compost activator. But its easy to circumvent that loss by adding urine to your compost heap or resting bucket if you want to give it a boost, either by the occasional collection or the ‘el-naturale’ method (the ever portable man snake is a winner here).

2. Less Odour

Separating the urine from the solid waste also reduces smell dramatically.

Less moisture = less odour overall.

The above picture shows the Sylvantutch toilet using the bottle collection method. The front of the toilet box has a hatch you can open to easily access the bottle.

3. Homemade Fertilizer

Another great benefit of separating the ones from the twos is that you get to use your urine in the garden.

Urine is fantastic for your plants! Its full of nitrogen, potassium and phosphorus, which are the nutrients plants need to thrive—and the main ingredients in common mineral fertilizers.

Coming straight out of the human body, urine is actually sterile and safe to add to soil.

Just make sure you don’t overdo it in a single area – think about how too much fertilizer can burn your plants if spread too thick or not diluted enough.

Types Of Urine Splitters & Collection Methods

You can buy specially made urine splitters to fit to your compost toilet, or buy ready made compost toilets that come with one.

You could probably also make your own splitter with a bit of trial and error, but it’s not something I’ve explored myself.

Some people use two separate toilets (one for urine and one for solids). Personally I don’t think that’s a very practical approach.

There are two options for urine collection:

  1. One is to have urine collect in a bottle (or similar) as part of your toilet set up. It’s instant set up, but ongoing maintenance as the bottle needs to be emptied daily to avoid a smell.
  2. Or you can have a pipe which funnels the urine away into a soak away, grey water system or banana circle. This takes a bit of planning and setting up, but once done, it’s sorted for life.
Two separate compost toilets
Compost toilet with bottle collector for urine
Compost toilet with bottle collector for urine

We’ll be going with the bottle method to begin with during phase one of our ‘moving onto the land’ plan. We first want to get a feel for everything before we lay down permanent pipes.

Urine Soak Away

Once we’ve lived on the land for a while and have locked in our building plans (and just gotten a better feel for the land), we’ll upgrade to a permanent soak away.

A soak away means using a pipe from the urine splitter to carry the urine away from the toilet.

The pipe is buried underground in a purpose dug hole filled with filtering material.

The Separett urine soak away
The Separett urine soak away

Apart from the immediate benefit of not having to empty the bottle collector every day! The added benefit is that you can set up your soak away in a spot of your choosing. Nitrogen loving plants grown over this area with thrive.

I still need to do more research into this step, but initial study suggests burying the pipe around 10cm into the ground and perforating it along its length (even adding several branched out pipes), so that the urine is spread out over a larger area for plants to use without being overwhelmed.

By keeping the flow towards the top of the soil and spreading it out over a large area, the risk of groundwater contamination can be offset. Since our plot is next to a river, we’ll need to do a LOT of research and fact-checking before we go ahead.

Increasing Waste Dehydration

Adding a ventilation pipe / chimney to the compost toilet set up naturally increases evaporation and removal of odours.

An extractor fan can further assist in drawing the warm, moisture laden air out.

The result is that the solid waste loses a lot of mass, reducing in size.

On the right is a great diagram illustrating the decomposition process with the use of a fan and ventilation pipe. Image from www.fabtoilet.com

Compost Toilet with dehydration

Ecosan’s “Corkscrew” Dry Toilet

Ecosan has a dry toilet available here in South Africa that involves a somewhat complicated corkscrew device to shift solid waste along a tube before dropping it, ‘dry and odourless’, into a collection bag, thanks to the combination of the slow corkscrew progress and the ventilation pipe.

Ecosan’s “Waterless Toilet” Design

Our Compost Toilet Design Plan

I’ve pulled information and bits of designs from many sources, but John Seymour’s “The New Complete Book of Self Sufficiency – The Classic Guide for Realists and Dreamers” was the first compost toilet I came across to improve on the simple long-drop, or pit latrine. His book has been a massive inspiration to me on all fronts, and has been one of the most referred-back-to books on my bookshelf for years.

John Seymour’s “Thunderbox Toilet” design

Here’s a breakdown of what I plan to do when we build our home:

Envirosan’s design is my main inspiration – the only things I’ve added are a slight slant to the floor, a fly screen and an extractor fan.

  1. Keeping the compost toilet with urine splitter, urine being diverted via a pipe to a garden area outside the house.
  2. Solid waste falling down into a large container on wheels. This container is housed inside a brick/cement chamber underneath the toilet, below the bathroom floor. The chamber is built with a slight downward angle.
  3. Outside the bathroom on the exterior wall, a ventilation pipe/chimney flue connects to the chamber, running up the side of the house to the roof. A fly screen prevents unwanted guests making their way down the flue into the chamber.
  4. An extractor fan fitted to the ventilation pipe inside the chamber increases the flow of air upwards.
  5. A hatch allows access to the chamber from outside the house, where the container can be wheeled out when full, and depending on the level of decomposition, either a second container rolled in while the first container is fitted with a lid to decompose further, or if its ready to go, emptied into the compost pile and returned.

Our toilet from Sylvantutch should be arriving next week – just in time for our next trip to Suurbraak for our first camp-stay on the land.

I’m probably more excited than I should be about a toilet, but what can I say – compost toilets make me happy!

Envirosan Compost Toilet Design
Envirosan Design
My very messy initial sketch that I was too lazy to redraw nicely for you (sorry)

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