As we began our research it became obvious there wasn’t just one composting toilet, in fact there were many! We started to watch videos of fellow boaters and campervan owners with some talking ‘urine separating toilets’ others ‘composting toilets’ and even ‘internal composting toilets’. We needed to determine what these different terms actually meant and how they would affect our toilet choice. This was more of a minefield than we had expected and it was not going to be as simple as we first thought!
Urine Separating Toilets
● Separates liquids from solids, reducing waste volume by 80% – no surprises there!
● Container for solids needs to be lined with biodegradable bags plus a layer of cat litter.
● Requires absorbent material, e.g sawdust or cat litter, to be added after each deposit – lovely, we get to view the poo!
● Do not always look like conventional toilets – plywood box with toilet seat fitted on top – so you can actually make a DIY toilet.
● Minimal decomposition until transferred into another container, stirred regularly and kept for approximately 12 months – that will be awkward on the overlander but may be possible on the boat.
● Or the solid waste is double bagged and placed in household waste – now you may think that doesn’t sound pleasant but it is no different to nappies or dog poo bags
● Urine can either be emptied in an ordinary toilet or under hedges/tree bases as well as Elsan points – now that will make life easier!
What about toilet paper I can hear you asking? If paper is added to the solids container it will fill quicker, so the other option is to either bag and bin or it can be burnt. Most boats have a wood/coal burning stove so this would be possible in the winter BUT we don’t, ours is a diesel stove! Also, no stove on our overlander so we would be bagging and binning.
● Separates liquids from solids thus reducing waste volume by 80%.
● Liquid level can be either seen from outside or there is an indicator.
● Coco coir, reconstituted with water placed in the bottom of the solids container to absorb liquid and keep material dry and odourless.
● Toilet paper can be put into the solids container.
● Integral stirrer/agitator with outer handle to be turned after every solid deposit, aiding decomposition by breaking up material and aerating.
● Most have a vent with a 12v fan running continuously to increase oxygen and aid composting.
● Appearance similar to an ordinary toilet.
Internal Composting Toilets
● No separation of liquids and solids.
● Composting happens within the toilet.
● Mainly rely on mains electricity.
● More limited options for boats/vehicles.
● Twice the cost of even the most expensive composting toilet.
Immediately it was apparent that an internal composting toilet would not be suitable for our use, plus it was way out of our price range. Great, that’s one off the list!
So we returned to our original list – see our first blog – of what we wanted to achieve from our composting toilet. We decided NOT to go down the route of analysing the amounts of our excretions as one website suggested, that really was a step too far! However, we felt we needed some sort of criteria to work from in order to find our ideal toilet.
Firstly we looked at urine containers and what we needed:
● Decent volume bottle – the average output for 2 adults in 24 hours is 2-4 litres, so a minimum of 5 litres capacity.
● Handle for easy carrying when emptying.
● Opaque but with level indicator – I would prefer to be discreet when heading to empty my bottle!
● Easy access for emptying/changing the bottle.
Moving onto the solids container we wanted:
● Monthly solid emptying – so approximately 60 uses.
● Round – nobody wants to clean those corners!
● An agitator/stirrer to assist with decomposition.
● Good construction, not too heavy and easy to empty – Nick is determined I won’t get away with not emptying this one!
● Does not require lining with bags.
We also definitely wanted a vent with a fan to prevent odors and we would prefer it to look like a toilet as we have designated bathrooms on both the boat and the overlander.
So you might be thinking, well that all looks quite simple but the research to get to this point took us over 6 months – now you know what we were doing during Covid lockdown!
You will have to wait for our next blog to find out do we buy or go DIY?