How Does Composting Toilet Work? (Here’s how!)

Living off-grid is a common trend worldwide as people seek exclusive places to enjoy camping with family and friends. For many years the challenge has been getting a sustainable toilet that does not involve digging pit latrines. 

One of the questions friends would ask is where they will dispose of their waste while living off-grid. That fear no longer holds ground with the invention of composting toilets. 

So, how does composting toilet work? A composting toilet is an alternative to flush toilets by disposing of human waste while minimizing water use. Composting toilet eliminates odor through an anaerobic processing method by mixing the waste with peat moss, sawdust, or coconut coir and venting the flow of air outward.

Most of these toilets do not need water and are not connected to the sewerage system or septic tank. Some are portable, meaning you can carry them wherever you are.

At the same time, others can also be permanently installed outhouse or in the house and are connected to the traditional sewerage system. 

Some people make their compost toilet- a humanure system, while others also buy both permanent and portable compost toilets. 

Before we consider how this facility works, let’s define it. 

You might enjoy reading: Best Ways Of Getting Water For an Off-Grid Bathroom.

How Does Composting Toilet Work
How Does Composting Toilet Work? (Here’s how!) –

What Is a Composting Toilet?

A composting toilet uses no water, so no plumbing is involved, no chemicals are needed, and no flushing; it’s completely natural. Think of composting toilet as a mini-ecosystem separating the liquids (the pee) and the solids (the poo) and converting the solids into humus. 

You probably know the sewerage system, where you poo or pee and flush the waste away into the sewerage system. However, composting toilets are an aerobic decomposition system that breaks down human waste rather than flushing it to the sewer. 

The composting toilet is a viable technology that can safely and efficiently manage human-generated wastes and conserve water and energy. With a compost toilet, the wastes are not flushed away but recycled by generating the environmental conditions needed to break down the feces and kill pathogens. (Source: Science Education Resource Center (SERC) by Carlton University)

These systems are suitable where there is no water or in places not connected to the city’s septic tank or wastewater system. 

Since it involves breaking down human waste, it is called a composting toilet. It functions like the regular composts that covert animal waste or kitchen scraps into manure. Human waste can also be composted into the dry and odorless matter to be used as fertilizers if the laws of your region do not object. 

Compositing toilets come in different systems; some have fans while others don’t. Some need power to function, while others work exclusively off the grid and do not need a power supply. Other brands also separate urine; some are fitted with liners for easy cleaning. 

Compositing toilets are divided into two main categories: active and slow. 

1- Slow Composting Toilets

Slow composting toilets are often located at remote locations and are infrequently used. If you have a cabin in the woods that you visit once in a while for a getaway, you can install slow compost toilets there. 

Generally, most composting toilets use slow composting, also called “cold composting.”

Furthermore, slow composting toilets are made with a box and a seat on the top. The box contains the compost system that holds your waste. The waste slowly decomposes, thus eliminating pathogens.

What Is The Difference Between a Slow Compost Toilet And a Pit Toilet? 

Although slow compost and pit toilets are mostly found in similar locations, they differ in several ways. A slow compost decomposes human waste with a resulting product at the end of its life. On the other hand, pit toilets are holes dug where humans excrete their waste and when it is full, it is covered over, and a new pit is dug. They do not have a resulting compost product. 

A compost toilet is better in remote places where toilets are used less frequently since they save labor and money. Also, they do not leave behind waste enclosed in a hole which could pollute underground water and cause diseases. 

2- What About Active Composting Toilets? 

Active composting toilets are named active because they have fans to ensure free oxygen circulation to speed up decomposition. Active composting toilets are bigger than flush toilets and keep everything enclosed in one unit.

Generally, active composting toilets resemble slow compost toilets because they need the addition of absorbent material to aerate the waste. However, that is where their similarities probably end.

Some levels are fitted with heaters to ensure the system is at the optimal temperature for faster waste materials degradation. Therefore, they need electricity to power the fan and the heater. 

 Some brands also have a starter culture to ensure the compost has enough bacteria for enhanced efficiency. Since active compost systems are calibrated and controlled, you will likely get pathogen-free compost in the toilet if you follow the instructions and keep the elements balanced. 

Active Composting Toilets Vs. Slow Composting Toilets: Which One Should You Choose?

Active compost is the ideal option if the toilet is frequently used since it decomposes waste faster. A slow compost toilet is good for remote campsites since they are used a few weeks a year. They are also suitable for places without electricity because active composting toilets need electricity to power the fan and the heater. 

In addition, choosing between a slow and active composting toilet depends on the location and frequency of use.

Before buying a compost toilet, the number of people using the toilet should also be considered. If you have many people using it, you will probably need an active composting toilet or install several slow compost toilets to cater to your needs.  

How Does a Composting Toilet Works?

Composting toilet comes with a trap door that leads into the lower tank (also known as the compost area). The liquids go directly to the front tank to keep the two from mixing and avoid chemical reactions that create the sewage smell. 

Additionally, composting toilet systems are in some way similar to a flush toilet. Most of them are designed with seats so users can sit while defecating. Seating on the toilet directs urine to the toilet system. 

After urinating or defecating into the compost toilet, you should add a carbon-rich material- often sawdust- to facilitate waste material decomposition. The broken-down human waste material can be used to fortify the soil if the laws in your region allow for such usage

The composting toilets vary in their functions from one brand to the other. The variation is also witnessed in the composting speed, storage capacity, and quantity of waste material depending on the number of users, air temperature, and toilet design. 

If you have installed a slow compost system, it might look like an old-fashioned outhouse. The system requires that you add sawdust, carbon-rich materials, or coconut coir after use. The waste will take time to compost. 

However, an active system may look like an enclosed flush toilet. They can be smaller or larger depending on the style and the number of people using them. 

Like the slow compost toilet, you will add sawdust or another dry carbon-rich material. The material helps to reduce odors and create spaces for proper aeration, allowing oxygen to enter the waste. 

The actual composting process takes place in the active and slow compost toilets. This process involves microorganisms such as fungi and bacteria that consume the materials and the waste. 

The microorganisms are less efficient in the slow compost system because lack of oxygen inhibits their growth. On the other hand, in the active compost system, organisms function optimally because of the perfect balance of heat, oxygen, moisture, nitrogen, and carbon inputs. 

The most common microorganism on these composts is the mesophilic organisms. It functions well at temperatures between 20 C to 45 C, showing why active composts perform better than slow composts. 

If you live in non-tropical areas where temperatures often drop below 20 degrees Celsius, the mesophilic organisms will become inactive, and the composting process will slow down or sometimes stop. 

You can also buy active composts with heat compartments to keep the organisms active. Nevertheless, when the system is effectively working, your compost is safe. The pathogens in human waste are often killed as the temperature in the system rise. 

Another thing you want to check in the composting toilet is the water levels. If the system has more water from urine, it can create an imbalance. You can avoid this trouble by opting for toilets that divert urine away from the compost. 

Watch the video below on how composting toilets work.

How Does Composting Toilet Work? (Here’s how!) –

Maintenance Of The Compost Toilets

It is easy to maintain the conventional flush toilets where after defecating, you simply flush your waste down the drain and walk away. On the other hand, composting toilets require regular maintenance, hard work, and discipline. 

What maintenance work will you do with compost toilets? For starters, you will need to regularly remove the compost from the system and put the garbage or bag it. Alternatively, you can use it on your farm as fertilizer. 

In general, a compost toilet dumping schedule will depend on how often you use it daily, how many people use it, and how much toilet paper you use. 

If your system does not separate urine from the compost, you may need to separate urine to create a balance and allow the microorganism to work on the waste materials properly. 

How often you will remove urine depends on the compost size and frequency of use. You may occasionally clean the compost’s exterior as with a regular toilet.

Final Words

Compositing toilets are incredible inventions that come in handy for those living off-grid away from sewerage systems. They are also relevant for remote campsites or life in a cabin. The microorganisms decompose the fecal matter and the added sawdust, leaving an odorless material that can serve as manure in the soil. 

Some compost toilets need a power source to function well, especially active composts, while others, like slow composts, don’t need a power supply.

Although composting toilets are convenient, they require regular maintenance. There you go; next time you are planning to go camping with friends, don’t leave your feces scattered in the bush! Buy a composting toilet and save the environment.


Hello friends, I am Altiné. I am SO excited you are here! I am the person behind Off The Grid Planet. Off The Grid Planet is about off-grid living, homesteading, and self-sufficiency: learning self-reliance, sustainable homes, gardening, survival, preparedness, and renewable energy and inspire you to live a simple life. I do my best to bring you the most correct, up-to-date, and comprehensive information on these topics.

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