How composting toilets work
Composting toilets work by breaking down human waste into compost through a natural biological process called aerobic decomposition. Here’s a step-by-step overview of how they function:
1. Waste Collection
Waste is deposited into the toilet’s composting chamber. Some toilets use multiple bins for batch composting, while others rely on a single container for continuous composting.
2. Aeration
The toilet is designed to maintain good airflow, which is important for composting. By using a whirlybird or a low-usage fan (solar or mains powered), proper ventilation brings in oxygen, needed for aerobic decomposition.
3. Composting
Microorganisms break down the waste, so it’s important to keep them happy. Human waste is high in nitrogen, so we add carbon-rich materials like hemp shavings, raw pine shavings, or peat moss to get the carbon-to-nitrogen mix just right.
4. Safe Humanure
After the composting process is complete, the resulting material is nutrient-rich and has a texture similar to potting mix. It can be safely removed from the unit and used to enrich trees, fruit trees, and flower garden beds.
1. Waste Collection
Waste is deposited into the toilet’s composting chamber. Some toilets use multiple bins for batch composting, while others rely on a single container for continuous composting.
2. Aeration
The toilet is designed to maintain good airflow, which is important for composting. By using a whirlybird or a low-usage fan (solar or mains powered), proper ventilation brings in oxygen, needed for aerobic decomposition.
3. Composting
Microorganisms break down the waste, so it’s important to keep them happy. Human waste is high in nitrogen, so we add carbon-rich materials like hemp shavings, raw pine shavings, or peat moss to get the carbon-to-nitrogen mix just right.
4. Safe Humanure
After the composting process is complete, the resulting material is nutrient-rich and has a texture similar to potting mix. It can be safely removed from the unit and used to enrich trees, fruit trees, and flower garden beds.
Types of Composting toilets
The many designs available can be divided into the categories below, all with their own characteristics, capacities and installation requirements.
1. Self-Contained Systems
These smaller, self contained systems have the advantage that they can easily be fitted into an existing toilet room without the need to have underfloor access to install and maintain a composting chamber. This is a feature most other composting toilets can not offer.
Their capacity can be increased, just by adding more spare composting chambers & lids. These can be purchased when the system is initially bought, or as the need for them arises.
Self Contained Composting Toilets are suitable for a smaller family, typically from 1 – 4 people in full time use. More systems can be added as required, catering to larger families sizes and depending on the number of bathrooms in situ.
Our self-contained models:
These smaller, self contained systems have the advantage that they can easily be fitted into an existing toilet room without the need to have underfloor access to install and maintain a composting chamber. This is a feature most other composting toilets can not offer.
Their capacity can be increased, just by adding more spare composting chambers & lids. These can be purchased when the system is initially bought, or as the need for them arises.
Self Contained Composting Toilets are suitable for a smaller family, typically from 1 – 4 people in full time use. More systems can be added as required, catering to larger families sizes and depending on the number of bathrooms in situ.
Our self-contained models:
2. Split Systems
Split systems usually have a higher capacity than self-contained ones, as the composting container is below floor and a conventional looking toilet pedestal is inside the toilet room.
There are two types of split composting toilets – batch and continuous.
Split batch systems have two or more containers that are alternated, so that the active container is being used while the fallow container has time to compost, without the addition of new material.
Split continuous systems have a single composting container. New deposits are added at the back of the unit and raked towards the front. By the time the front of the container is full, this section is fully composted and ready to be emptied.
Split systems usually have a higher capacity than self-contained ones, as the composting container is below floor and a conventional looking toilet pedestal is inside the toilet room.
There are two types of split composting toilets – batch and continuous.
Split batch systems have two or more containers that are alternated, so that the active container is being used while the fallow container sits aside and has time to compost, without the addition of new material.
Split continuous systems have a single composting container. New deposits are added at the back of the unit and raked towards the front. By the time the front of the container is full, this section is fully composted and ready to be emptied.
Our split-system models
(high use/commercial ):
Composting toilets in the media
‘I am a big fan of composting toilets’
“I go to my cabin in the woods and have my off-grid weekends and then think what can I bring back from that? It
is a journey of exploration, trying out ideas, asking how can that inform every day living.”
“Do I put in a reed bed, a biodigester, or a composting toilet? I am a big fan of composting toilets – I like the cycle
of using waste. When you have experienced one and seen what comes out of the bottom, it is amazing stuff. It’s
the most beautiful, driest, sweet-smelling compost.”
‘Grand Designs’ presenter Kevin McCloud
‘I am a big fan of composting toilets’
“I go to my cabin in the woods and have my off-grid weekends and then think what can I bring back from that? It
is a journey of exploration, trying out ideas, asking how can that inform every day living.”
“Do I put in a reed bed, a biodigester, or a composting toilet? I am a big fan of composting toilets – I like the cycle
of using waste. When you have experienced one and seen what comes out of the bottom, it is amazing stuff. It’s
the most beautiful, driest, sweet-smelling compost.”
– ‘Grand Designs’ presenter Kevin McCloud