Want to understand more about compost toilets?
In this section, we'll attempt to explain the basics of how our compost toilets work, help you understand the differences between the models, so you can choose the right one for you, and go on to explain their day to day maintenance. Please explore the other sections in the Help menu for more information, and if anything is not clear, do get in contact!
Remember that a compost toilet is a part of a whole system - the other key part being a compost bin. The toilet is essentially the collection system for the raw ingredients that will be completely broken down and made safe by the composting process. Keeping the collection and composting separate means that the compost toilet can be simplified - and simple is good! Nothing mechanical to break, no enormous energy bills and a nice compact toilet that doesn't take up much space!
Easy management is all about separation!
The key to a low-maintenance compost toilet is keeping the liquids away from the solids.
This keeps maintenance and odours easy to deal with and emptying less frequent.
The urine separating bowl is the starting point - we use the best ones available!
When you mix urine and faeces together, you get 'blackwater' which will quickly become smelly as things start to break down in the absence of oxygen. You could use a simple bucket system (to collect wee and poo) and add a lot of sawdust (as a cover material/odour control) but having somewhere to store and then compost the contents means you'll need a fair amount of space and a fair amount of time to manage it. If you want something that needs less maintenance, read on...
The answer is to separate the wee from the poo at source and deal with each one individually. This is where the urine diverter or urine separating bowl comes into play...
It works on a simple principle - when you sit down on the toilet, urine will flow to the front and faeces will drop down towards the rear. It doesn't matter whether you're male or female, it works the same.
The separator is specially designed and has a front part to capture and direct the urine, and a chute towards the rear that ensures solids go straight down into the container below.
Separators can be made from either plastic or fibre-glass, meaning they are wipe-clean, durable and very hygienic. The fibre-glass separators used on the Eco-Loo and Kildwick products also have SteriTouch anti-bacterial agents embedded.
Where does the wee go?
Where the urine goes in a compost toilet depends principally on whether your toilet is in a permanent land-based building, or whether you're on the move (on water or on land).
If you're on land, then the easiest and simplest option is to to run the urine into a small soakaway pit. We have a section covering soakaway pits in detail, but essentially it's a small hole, filled with gravel, hardcore etc into which the urine will run. The large surface area slows the flow and enables naturally-occurring soil bacteria to feed off the nutrients in the urine and render it harmless. Any excess will gradually and slowly dissipate in the ground.
The soakaway doesn't require any maintenance and it doesn't smell. It's a simple and effective solution for permanent and semi-permanent land-based installations.
Great compost toilets for land-based users include the Eco-Loo Divert, The Kildwick Kabin Divert, and the Separett Villa 9000 or Villa 9010 - check out our shop for more details.
If you're not on land, or you're on the move a lot, or ground conditions dictate otherwise, then a soakaway pit isn't an option. In these cases, you'll need a compost toilet with an internal urine storage container that you'll have to empty regularly (ideally daily). Rather than diverting the urine outside, it runs into a container within the toilet itself. When it's needs emptying, open the toilet, pop the cap on the bottle and use the convenient handle to carry the container to a suitable place for emptying. This can be an 'elsan' point or other approved disposal area, or under a tree (make sure the disposal area is at least 10 metres from a water course and vary the actual spot).
Remember that you should never discharge urine into a water course, canal, ditch etc - the concentrated nutrients can lead to excessive algal growth. There are regulations prohibiting urine discharge into all UK canals and an increasing number of rivers.
Urine, also makes a great fertiliser, so some people like to capture it, water it down and apply it as a feed to their garden...
Ideal compost toilets for mobile users include the Eco-Loo Capture, Kildwick Kabin Capture and Kildwick Koodle. You can also use a diverting compost toilet connected to a removable tank or container.
What about poo?
Because of the separating design of the bowl, poo or solids will drop down into a container within the toilet. This container usually has a biodegradable liner and a layer of wood shavings in the base.
Because it's just poo, it will be fairly dry and the volume is likely to be much less than you might expect. In addition, it will continue to dry out, reducing the volume over time. However, it will smell, as you'd expect, so let's look at the options you have...
We'll start with the simplest option - wood shavings. They require no electricity or additional ventilation (although we do recommend that the room the loo is in is well ventilated) - all you do is cover what you've done with wood shavings (a handful or two is usually enough) and that's it. Wood shavings are commonly sold in small packs as pet bedding, and are slightly coarser than pure sawdust (which is too fine) and work as a biological cover, enhancing the subsequent composting and reducing odours.
There are loads of other cover materials besides wood shavings and we have a section going into more detail, but shavings are readily available and inexpensive, so become the 'go to' for a lot of people. Wooden cat litter pellets are also good, but wet them slightly so they crumble first.
If that sounds a bit too rustic and not your thing, or you need to make it really simple for people, then some models either have an optional fan, or come with a fan as standard, which will pull fresh air over the solids container and push it out it outside through a vent, where it will quickly dissipate.
The Eco-Loo range has an optional fan, as does the Kildwick Koodle. The Kildwick Kabin and Separett Villa come with a fan as standard.
Some of the fans we supply can run from 12V or mains (with an appropriate adaptor), so are great for off-grid use where you have a solar panel for example. The fan is typically designed to run constantly and is effective at odour removal. It's still a good idea to have some wood shavings on hand so people can use it as a modesty cover, and the carbon in the shavings is important to the subsequent composting process.
How long the solids container lasts before needing to be emptied depends on a number of factors - the number of users, whether you use a lot of woodshavings, how much toilet paper you use... As a rough guide, a 20 litre solids container would last a single person between 4-6 weeks if they didn't use any other toilets - the use of woodshavings etc will reduce this...
So that's it - now you know the basics of how a waterless urine diverting compost toilet works! You just sit down, do what you have to do, and go! Simple, effective and in some cases, no moving parts.