Separett Villa Installation on a New Narrowboat

While we were in the process of getting a new narrowboat built we decided to go for a composting toilet. We had experience of a macerating pump out toilet on our old boat and whilst it worked fine we were concerned about the rising costs of a pump out as well as the fear of it breaking down at an inconvenient moment. Also if we were to become iced in or immobile for some other reason we would have a problem with emptying the tank. We had no experience of cassette toilets but generally didn’t fancy the idea of having to frequently find an elsan point to empty the cassettes.
We decided on a Separett Villa toilet. We have friends who have one and spoke well of it. We didn’t like the look of an Airhead, preferring a more “normal” looking toilet and we weren’t aware of the Kildwick range at the time (2015).
The boat builders (Finesse Boats) had never fitted a composting toilet before but were quite happy to discuss the idea. They looked at the spec of the Separett Villa and they came up with the idea of fitting a 20 litre tank under the floor for the urine with a shower pump to pump it out when required. They wanted to fit a stainless steel tank, but we persuaded them it should be plastic instead. The thinking behind this being that if we ever needed to use some form of acid to de scale the tank or clear a blockage the steel might corrode. They fitted two outlets on the gunnel, one for normal use and one for use with an external pump should the built in one fail. The outlet connects to a hose fitting and we have a length of hose that goes into a black 23 litre portable container. The builder also fitted a tank vent pipe which exits through the hull below the gunnel.
They ran the toilet vent pipe up to the roof through its own mushroom vent. We leave the fan on all the time but I have changed the fan for a quieter one: a 92mm pc fan https://www.quietpc.com/gel-silent9 from https://www.quietpc.com/ . The 12 volt power to the fan is via a regulated 12v supply and not direct from the batteries. The original fans as supplied from Separette apparently have a habit of failing prematurely when connected to an unregulated supply.
After pumping the tank contents into the container we empty it either into the hedgerow, if suitable, or use an elsan point if one is handy. After emptying we rinse twice by pouring about three litres of water down the toilet and pumping it out again, then pour some Ecover toilet cleaner down into the tank. We empty the tank about every three or four days. Also after every use we spray some diluted white vinegar onto the urine area to try to eliminate calcification and to prevent odours.
There is nothing special about the solids bucket. At the moment we bag and bin. We continuously cruise and don’t have facilities for storing full buckets. We line the bucket with two compostable and marked bags supplied by Kildwick. We use wood pellet cat litter at the bottom and for cover we use small animal bedding wood shavings available from supermarkets. With two of us living aboard the bucket lasts about two weeks before needing to be taken out.
We are very happy with the way it all works and much prefer not having to spend £20 on a pump out every two weeks.

Figure 1. Toilet showing vent pipe

Figure 2. Rear of toilet showing urine pipe

Figure 3. Pipework

Figure 4. Tank and pipes

Figure 5. Gunnel Fittings

Figure 6. Hose and container. We have a longer hose for when the towpath is on the other side.

Figure 7. Hose connector