The decision was helped by the surveyors report, which highlighted a hole in the storage tank used for the macerator toilet.
Eventually the vendor agreed a suitable reduction in the price of the boat and we were left to decide the way forward
- Weld a panel over the hole and hope there were no other problems. Not an option we wanted to risk
- Replace the holding tank with a plastic one
- Remove the tank and change to a porta-potti / cassette
- Remove the tank and get a composting toilet
After a great deal of thought we decided to go down the composting toilet route. Even before we purchased a boat it was something that we were interested in, even though very few people have them on narrowboats at present. We did plenty of research on the subject and found that almost everyone who had an Airhead or the similar Nature’s Head seemed very happy with them.
Both models come from America where due to their laws on dumping waste in coastal waters they have been widely used on sailing boats for years, . So they have a good history. Another option is the Separett range from Sweden
If you don’t like toilet talk, now may be a good time to stop reading. For many though its a popular topic of conversation.
The perception of composting toilets on narrowboats seems to be that they are smelly and that flies get in. This relates to older toilets where the solids and liquids are mixed in together. Newer models keep things separate and this avoids the problems.
How are they fitted ?
The main issue with fitting is the need for a hole to be made in the boat roof, for the ventilation hose that attaches to the side of the toilet to exit through. There is a very fine filter in the hose to prevent any insects getting into the toilet.
On the top of the hose is a fan which can either be connected to your 12V supply or as we have done, a solar vent with a small fan and a battery can be fitted. The fan only uses about 1.5 amps per day, so the solar panel charges the battery up enough to keep the fan going at night. The fan is similar in size to a computer fan and can not be heard inside. It needs to be on all the time.
We already had a hole in the bathroom wall for the macerator flush and 2 holes in the roof for the pump out and vent. We were therefore able to have the pipe well hidden and the vent fitted over the 2 existing holes.
Apart from that, the fit-out only needs 2 brackets to be screwed to the floor and enough space for the crank handle to turn.
Here is an excellent video showing how it all fits together.
How does it work ?
Before using the toilet you need to add some cocoa shell husks to the solids tank. A bag for the first fill is supplied. You can then buy large bags from garden centres which should see you through a year. Some people also add some compost activator to get the compost process going quicker.
For the liquids tank some people add a spoonful of white vinegar or a sugar cube to minimise any possible smell.
For toilet paper its recommended that you use cheap paper as it decomposes quicker. To keep the solids tank dry ladies may want to have a separate bag for paper.
Now down to doing your business. Men – its better if you sit down to pee, cos’ you know you are a rubbish shot and splash it all over the place when you are standing and you need to keep the solids tank dry.
The bowl has holes near the front, from here the pee empties into the 2 gallon pee tank. It makes you jump first time, as the sound of the pee going into the tank, sounds like its falling onto the floor by your feet.
For solids there is a handle on the side of the toilet, turn that and it opens a trap door for solids to drop into. If you don’t want to see inside the solids tank, sit down then open the trap door. Ideally pee first, then open the trap door to avoid any chance of pee going into the solids tank.
When you have finished toilet paper goes through the trap door as well. Then close the trap door and turn the crank handle a few times to mix the solids and cocoa husks together. That’s it job done. Nothing to flush, nothing to clean on the pan and no chemicals needed.
Another option which some may prefer but I haven’t felt the need to use, is coffee filters. If you are squeamish about having the trap door open you can place one of these in the bowl, make your deposit into this and then drop it down the trap door. We are keeping a few for guests who may feel more comfortable using this method.
How Often does it need emptying ?
Well the simple answer for pee is as long as it takes for you to produce 2 gallons of pee. For 2 of us its every 3 days, if you like a few pints it may be more like 2 days. Remove the pee tank and put the supplied screw top cap on, then empty it down your nearest Elsan point. As urine is sterile it could be spread around the undergrowth (think how much a cow deposits in one go) if you can’t get to an Elsan. Compared to emptying your cassette the weight is much less to carry and its a no fuss job.
For the solids tank, work on about once a month if its used daily. The toilet is in 2 halves and you simply unscrew 4 wing nuts to separate the top from the bottom and then release 2 wing nuts to lift the tank off the floor for emptying. Don’t forget to remove and cap the pee bottle first or you could have a major spillage.
By the time you empty the bowl it should be pretty dry (except of course for the recent deposits) and it can all be emptied out and put into another container. By this stage it won’t be good enough to use as compost yet, but it should be good enough to be used in your flower beds in a couple of months time. Its not recommended to use it on vegetables and fruit. If you can’t store it, it can be emptied down an Elsan, or put into strong bin bags and disposed of in a safe manner or possibly buried.
For more details on a technique for emptying and cleaning the solids tank read this post from NB Valerie who has had an Airhead for a couple of years.
The only other thing we use is some Ecover bathroom cleaner to give the bowl an occasional wipe down. As the solids go straight through a trap door there shouldn’t be any marks left on the pan wall.
So does it work ?
Well we have only been using it for 3 weeks and haven’t needed to empty the solids tank yet. However we can happily report that there is no smell at all from the tank and the composting process is well under way. As we worked in a youth hostel for many years and cleaned the toilets every day we aren’t at all squeamish, but really there is nothing to be squeamish about. So far I can say that we are very happy with our decision to go green and switch to a composting toilet. I intend to do a further update post in a couple of months time
Still not convinced ? Consider the advantages.
Cassette / porta-potti
No tricky manoeuvre getting a cassette in and out of the boat
Only a pee tank to empty every few days and it weighs much less
No splashes when emptying
No special toilet paper
If no Elsan available, it could still be emptied safely
Much less stomach turning to empty
Solids only need emptying about once a month
You can get a spare pee tank (about £50) to use if you are stuck inside
No water needed
No toilet brush needed
Its a similar frequency for emptying but its free. That could be a saving of over £200 a year.
No worries about not been able to get to a pump out in the Winter
No need to have a porta-potti ‘just in case’
No water needed. How much of your pump out is for the flushed water?
No macerator to break down
No toilet brush needed
No noisy mechanisms
That seems powerful arguments to me.
So how much is it?
The Airhead is currently £799, or £829 if you want a wooden seat. This includes all the fixtures, fittings, fan and also includes a starter portion of cocoa husks and some coffee filters. A vent is not included as people are likely to want one to match their boat. The solar vent was £70.
For much more information and advice, Richard at Eco-Toilets is the man to speak to. He has 15 years of experience and is happy to help.