In this post I’ll explain why I chose to use a compost toilet and, more specifically, a simple biolitter type.
The waste of an expensive commodity like mains water was something I was keen to avoid. After washing, toilets are the biggest consumer of domestic water. A report by the Energy Saving Trust in 2013 found that 22% of water consumed in UK homes was used to flush toilets. Furthermore, it just seems crazy to use high quality drinking water to flush a toilet.
An alternative is to use a compost toilet. Having previously read about simple compost toilets (and seen them in use at an eco-centre) I decided early in the design process that I would use one for my tiny house.
Free Garden Compost
A further bonus is the recycling of human waste and kitchen scraps to make a high quality compost that can be used in the garden. To be fair, it’s not completely free as you normally have to buy the ‘biolitter’ (sawdust, wood shavings, etc) to which the waste is added. However, I had lots of hemp left over from the build which was ideal for this purpose.
The Biolitter Toilet
The compost toilet system I chose was popularized (in French speaking Europe at least) by Professor Joseph Országh of the Université de Mons-Hainaut in Belgium. He called his system the “toilette à litière biomaîtrisée” or TLB . This can be literally translated as “biocontrolled litter toilet” or “biolitter toilet” (BLT). US readers may be familiar with a similar system called Humanure proposed by the American Joseph Jenkins.
For the benefit of this website’s English speaking readers, I’ll stick with the term Biolitter toilet (or just compost toilet) and avoid the acronym BLT, for obvious reasons!
Whatever the name, the principle is the same. In place of a normal toilet is a bucket with a volume of 20-40 litres. Around the bucket is built some kind of containing ‘box’ with removable top. This top has a hole around which is fixed a toilet seat and lid.
After each visit to the toilet, the waste (solid and liquid) is covered by a layer of ‘litter’ which is typically wood chips, wood shavings or sawdust. The cellulose in the litter biologically inhibits the enzymatic reactions in the excreta that are responsible for odours. Nevertheless, the bucket should be emptied at least once per week.
The bucket’s contents are then composted for at least two years (along with kitchen food scraps etc) after which the compost is safe to use in the garden.
I briefly considered other types of compost toilet but they seemed to be more expensive and complicated. I didn’t see the point of buying a commercially made item when I could make a very simple, proven and low cost system myself.
The Biolitter toilet in practice
I used a home made outside biolitter toilet for two summers while the tiny house was being built. It was very simple and convenient. You can read about it here.
In the summer of 2021 I started using a biolitter toilet inside the tiny house. This time I used a plastic bucket type toilet with an integrated seat and lid and it was placed in the shower room. This toilet is very compact which was ideal for the small space available. In practice it has worked well. Even my teenage daughter has given it the thumbs up for it’s practicality and surprising lack of odour! She even says that she will use a compost toilet in her house when she is older.