How a composting toilet works
We get asked all the time “how does it work?” So, we have compiled a list of our key composting principles and how to keep the balance.
In a nutshell, you’re introducing the bacteria (and fungi) into your composting chamber and these little organisms are eating your waste and converting it into usable material. This is the composting process, so it’s all about maintaining the environment for these microbes to do their job.
To avoid most of the science about microorganisms, these principles are everything that you need to maintain an environment where they can thrive.
Microbes are like us in the fact that they need moisture to live but not too much that they drown or too little that they dry out. Balancing moisture can be difficult at first because it should be ‘not too dry and not too wet’. This means it shouldn’t be too dry so that it creates a crust like a cow patty and shouldn’t be sopping wet so that it is soggy and drips; your compost pile should be like a freshly opened bag of potting mix or coarse coffee grounds.
Adding bulking agent to your compost pile (after a solid deposit) is the main way that moisture is absorbed, which creates the perfect moist environment. With too much bulking agent or too little liquid, the pile will dry out starting from the top because the moisture will naturally filter down. This dry environment means that your microbes will become dehydrated and go into hibernation, slowing down and eventually halting the composting process.
At least too dry is easy to see from the top of the pile, but if liquid is pooling up in the bottom of the chamber it can be harder to see and easier to identify by the smell. This is usually caused by too little bulking agent or a blocked leachate drain, creating an anaerobic environment (like a septic tank) and will kill the microbes.
Aerobic composting, as the name suggests, requires oxygen because these microbes, like us, need to breathe. Keeping the fan operating and air flowing through your composting chamber will keep your microbes happy, as well as the added benefits of deterring bugs and smells - read up on why you should check your vent pipes regularly for more information.
Coarser bulking agents, like pine shavings, forms a better structure in your compost pile and can form tiny air pockets. Imagine these little air pockets like small oases for your microbes inside the compost pile as they contain oxygen and also give moisture room to evaporate.
The composting process naturally creates heat, thanks to thermophilic microorganisms. Thermophiles are types of bacteria that thrive at relatively high temperatures, between 41 and 122 degrees celsius!
The thermophiles are producing their warmth (and you have the warmth from human waste), all we need to do is insulate and maintain those temperatures. Our Nature Loo Low Profile has a double-walled design to help maintain a consistent temperature as well as facilitate airflow. To prevent the chamber from cooling down during the winter months, the variable fan speed can be dropped to as low as 6 volts.
Cold temperatures will cause the microbes to slow down and they will hibernate through extremely cold temperatures. This means through winter, the composting process will slow day and may even cease. But they will come back out of hibernation when the conditions are right again.
4. Carbon and Nitrogen
Looking after the carbon and nitrogen levels is like maintaining a balanced diet. In (very) layman’s terms: for your culture of microbes, the carbon is what their cells are made of and nitrogen is their energy source.
The source of nitrogen in your compost pile will predominantly be urine. If you are familiar with fertilisers, especially for citrus plants, they contain nitrogen because it is really important for plant growth. So urine diverting toilets, or not urinating in your composting toilet, can cause a lack of moisture and nitrogen in your compost.
On the other hand, your main source of carbon is actually your bulking agent. This creates the nice living environment for your microbes, remembering what we said earlier about the bulking agent absorbing moisture and creating structure.
At the end of the day your microbes are pretty good at looking after themselves. With the right conditions they can thrive without much maintenance other than regular waste “deposits” from you. Looking for obvious signs like strange smells or unusual visual consistency in your heap could be an indication of a larger problem, but if you’re ever unsure our expert team are always available to help.