Up to now, ‘convention’ went that the toilet choice for boats and general off-grid living has been between cassette toilets or pump-out toilets (inc. septic tanks for land-based use). Indeed, this is an almost weekly discussion point on boat community forums, with vans & tiny houses having even greater restrictions. At least, that was the convention up to today – maybe things might start to change this year…
Hello and welcome to 2016! It’s been only a year since I started the ‘Compost Toilets for Boat and Off Grid Living‘ Facebook group and so much seems to have happened since then. Whilst I knew there was some interest in compost toilets, I never believed that the group would grow to over 700 members in less than twelve months. The recent article in Towpath Talk and another on commercial compost toilets in 2015 are a further indication that, maybe, now is the time for compost toilets to find their true place – as a viable and positive choice alongside cassette and pump-out toilets.
\The most oft-seen response to compost toilets as a suggestion is ‘oh, no…that’s disgusting,’ and ‘…it’ll smell awful’. Another common response is “…I knew someone a while back who had one – it stank and was a mess!” Those who make these comments seem, through experience, to be conditioned to forget just how awful cassette & pump-out toilets are and unaware that the world of compost toilets has moved on! As in many things, the modern reality of compost toilets is very different from past experience or misconceptions.
Anaerobic bacteria thrive where there is very little oxygen – the by-products of this process are gases that have a bad smell. Cassette and pump-out toilets are perfect for smelly anaerobic bacterial ‘digestion’
To understand why cassette toilets, pump-outs and old-style compost toilets are so bad you just need to open the cassette flap when full or be around a pump-out when emptying it. The mix of urine and poo encourages anearobic digestion by bacteria and this results in an awful smell and sludgy mess. Of course, you can add ‘perfumes’ into the mix but these don’t completely work and are not very eco-friendly. Previous forms of ‘self-contained’ compost toilets also allowed the urine and solids to mix so this often also resulted in an awful sticky mess and gave early composting toilets a bad name.
The new technology and key market ‘disrupter’ has been the development & application of urine diverters whose task it is to divert the wee away from the poo. Moving forward to more recent history came the the concept of ‘urine separation’ into designs. By keeping urine and solids apart you accomplish a few important things:
- Solids mixed with some dry carbon material, like sawdust, do not get the chance to develop the anearobic bacteria which made older self-contained compost unpredictable.
- The urine is collected in a separate bottle which is easily/conveniently emptied. A 12L urine bottle will last 6-12 days for one person depending on much you drink – longer if you use facilities at work/elsewhere. A smaller bottle can be emptied daily with ease.
- The solids container lasts a long time – typically we produce around 1/2L of solids a day but 1L-2L of liquids. Therefore a 20L ‘bucket’ will last 40 days for one person – again, longer if you use facilities elsewhere.
- The solids container fills slowly – you don’t /suddenly/ find it full – you have a week or more to get around to replacing the bucket with an empty one and ‘sorting’ full one (see other articles on this)
- The urine container will need more regular emptying than the solids – but as its no problem to empty there is little or no inconvenience.
The Kildwick Urine Diverter has been designed to meet tough requirements and has been family-tested and proven in boats, cabins, campsites and vans around the world
The key characteristics of a good urine diverter are:
- Must capture the majority of the urine – this is easier said that done as wee patterns for men, women and children can be quite different.
- Must reduce chance to urine pouring over the back of the diverter
- Must be easy to clean
In addition, Urine diverters made for DIY toilet builds must have some additional characteristics
- must be easy to fit – ideally coming with fitting kits and fixing points already present
- must be strong – not prone to breaking/damage when fitting or using
- must have a versatile ‘spout’ enabling use with hoses, various plumbing fittings and direct to bottle installations.
…and, of course it should really look nice too – that’s why I developed a clean white ‘sanitary’ model and also some lovely glitter models that add glamour but retain a smooth, shiny, easy-clean surface.
Today, compost toilets are easy and low cost to build yourself with several choices in the UK for custom-builds to suit your own bathroom space and personal style preferences. If you have a little more money to spend you can buy very nice commercial units but, in terms of function, they do much the same job than something you can build yourself or ask to be built for you.
Owning and running a compost toilet in 2016 could not be easier:
- Many choices to buy or build with cost options to suit any budget with functional results very similar across the range of products
- If you’re unhappy with the commercial ones, don’t want to spend that much money (£600->£1500), and don’t have the DIY skills you can one of commision several companies (inc. us) to build you a beautiful toilet to fit your bathroom space.
- They don’t smell – well, perhaps a musty dampness but nothing like cassette, pump-out and old-style composting toilets
- Longer periods between emptying – much longer!
- Much less hassle when it comes to emptying the urine or managing the solids – no panic to find the nearest elsan or pump out.
Compost toilets can be glamourous – we manufactrure glamourous glittery urine diverters which retain the same hard, shiny, easy-clean surface.
After fifteen years of using cassette toilets on our boats we made the change in 2014 to a urine-diverting compost toilet and have never looked back.