composting toilet

What is a Composting Toilet?

The zero-waste movement has grown in popularity, and with so many people looking for ways to reduce their waste, the ingenuous idea of the composting toilet has made quite the mark, introducing a cleaner, greener and environmentally friendly way to ‘spend a penny.’

In short, a composting toilet is a kind of toilet that turns human excrement into compost. Using biological processes, it creates an oxygen rich environment, which helps the waste to decompose aerobically.

Composting toilets are also known as dry or water-less toilets, because unlike standard toilet systems, they are not connected to the main sewerage system.

They are a fabulous option for boats, campers, RV’s, tiny homes and off grid living, but they can also be used in city homes, depending on the regulations of your specific area.

compost toilet

How does a Composting Toilet work?

Composting Toilets work very much the same to garden composting piles, where you would normally put your fruit and vegetable peels into.

The most important factor of the Composting Toilet is having the correct carbon to nitrogen balance, else the waste will not decompose properly.

In order to start off on the right track, Composting Toilets will need to be prepared with a base when the chamber is empty, much like a compost pile. For this, you can use something like peat moss or else coco coir, or sawdust.

Every time new solids are dropped in the chamber, a dry bulking material should be added on top of the solids to keep the correct ratio of Carbon to Nitrogen.

Once the chamber is half full, the decomposing process begins.

There are different kinds of Composting Toilets, which we will discuss later, but no matter which one you choose, all Composting Toilets must work on the correct temperature, moisture level and carbon to nitrogen ratio in order for proper and odor free compost to be produced.

This means that urine (liquids) must be separated from the solids.

Typically, most of the waste in the toilet will be liquid (water and urine). However, as liquids enter the toilet, they will evaporate through a combination of heat and air, and will be extracted back into the air via the toilet’s venting system.

The solids will then be left to break down into the compost.

Some Composting Toilets collect urine and faeces in that same chamber, but others don’t, and will convey the urine elsewhere. This is to prevent moisture build up, which will result in unpleasant odors, and disrupted decomposition.

The Composting Process

Sun-Mar’s Unique Bio-Drum

A Composting Toilet has four main parts:

Storage / Composting Chamber

The is basically where your waste goes after you have used the toilet.

It will separate the liquids from the solids by directing the liquid to the deepest part of the chamber. There is where it will begin an aerobic process to convert it into a nitrogen rich liquid. The solids go into a separate chamber and begin their decomposition here.

A Ventilation Unit

This unit helps with providing air (oxygen) which is an essential part in the decomposition process. It also helps get rid of odors.

Urine Collection System

This allows for removal of any excess liquid that may be inhibiting the proper decomposition process. Remember, that a little moisture is needed for good compost to form, so urine is not completely an enemy of compost.

It is nitrogen rich, which will help in producing a brilliant fertilizer!

Door for collection of compost

This is the place where you can collect your compost and use it

Like a garden compost heap, Composting Toilets need:

  • Air (oxygen)
  • A warm environment
  • Aerobic bacteria
  • A bit of moisture

In the correct environment, when faeces makes contact with oxygen, it breaks down naturally into compost.

Bacteria, fungi and worms are responsible for creating this biological process, which is aerobic decomposition, meaning decomposing in the presence of oxygen.

The moment when matter decomposes in an anaerobic fashion, that’s when odors will appear. That’s why it is essential to have the right balance of carbon to nitrogen (solid to liquid)

If you want the decomposition process to be faster, then you can add more carbon rich bulking materials, such as sawdust, paper, leaves and wood chips. These help to absorb excess moisture.

Like a regular compost pile, it will also need to be turned every once in a while.

composting toilets

Types of Composting Toilets

There are so many different kinds of composting toilets, that it can get very confusing to know which one to use.

Let’s have a look at them:

Active Composters:

Self-Contained Composting Toilet

These types of Composting Toilets have their toilet and composting unit in one chamber, meaning the composting process is taking place in the same area as where you go to the toilet.

It’s not as bad as it sounds though!

These kinds of toilets are great for tiny homes, or for people who don’t have a lot of space.

They are generally smaller and should not be used for more than two people.

They can be electric or non-electric.

Self-Contained Composting Toilets like the Nature’s Head brand require no water and no plumbing.

They are easy to clean, compact, and like all composting toilets are highly economical and Eco-friendly.

Central / Split / Remote Composting Toilet

This is where the toilet comes in a two piece.

The actual toilet part sits on top in the bathroom and the tank sits below the floor, such as a basement or underground room or else at another area away from the bathroom.

The central toilet can handle larger families and are a bit more expensive than the self-containing ones.

The central toilets give more of a traditional look to the bathroom, and is great for people who have more space in which they can set up a separate tank.

The Sun-Mar Centrex non-electric central Composting Toilet is a great example of the central system. Obviously, this will require a bit more time in order to set up, as the toilet will need to be connected to a pipe that will convey the waste down to the tank.

However, it is easy to set-up and maintain.

Continuous / Single Composter

This relates to the amount of collection chambers your composter will have.

You get two types: a continual / single or else a double / batch system.

A continuous or single composter has only one chamber, which means the composter will break down very slowly and will only be able to be harvested after a year.

Double / Batch Composters

These toilets have two or more chambers which rotate, so when one is full, an empty one will be used, while the full one decomposes.

Electric or Non-Electric Toilet

Electric Toilets work faster than Non-electric, because a fan and controlled heating are powered by electricity, such as the Sun-Mar Compact Self-Contained Toilet.

Solar Composting Toilet

This would be a toilet powered by the sun.

Obviously solar panels would be needed for this.

outdoor composting toilet

Benefits of Composting Toilets

By opting to install a Composting Toilet, you are support a cleaner, greener and more sustainable way of ‘going to the toilet.’

Let’s look at some benefits of the Composting Toilet:

  • They reduce water consumption, as they don’t use water.

Those that do use a flush system, will use a bit of water, but it is still considerably less than what a conventional toilet will use. An example of a Low Flush System would be the Sum-Mar Sealand Composting Toilet.

  • They use 1 pint of water per flush
  • They are not connected to the main sewerage, thus reducing the amount of sewerage coming from your home.
  • The compost that they make nourishes and enriches gardens and crops, instead of going to landfill.
  • They are viable options for communities who have no running water or sewer systems as they don’t need water to work.

Disadvantages of Composting Toilets

Let’s look at some disadvantages that come with a Composting Toilet:

  • You cannot just ‘go’ and be done with it. This is a toilet that need to be properly maintained.
  • You have to ensure that the waste is decomposing correctly, as improper decomposition of the waste can lead to diseases if humans and animals come into contact with it.
  • If you choose an electric toilet, it will obviously need electricity to operate.

Frequently Asked Questions

Do Compost Toilets smell?

The air vents in the toilet will reduce any odors and if the waste has the right conditions (oxygen, warmth, and the correct carbon to nitrogen ratio) to decompose, then it will not smell.

Foul odors come from improper maintenance.

Can I use toilet paper in a Composting Toilet?

Yes, you can! The paper acts as a carbon source and will be composted along with the waste.

What are the regulations regarding Composting Toilets?

This is a hard question to answer because each country, and even each state or county can have their own regulations.

It is best to either google the regulations for your specific area, or else phone someone from your council.

What are some common problems with Composting Toilets?

Improper maintenance can cause problems such as smells to arise, which will attract insects and harmful pathogens.

These problems can be easily remedied though.

Usually, adding more carbon rich bulk can help the problem.

Another tip is to make sure your fan is working properly and that the filter is always clean.

What about Composting Toilets and menstruation?

Many women want to know if they can dispose of period blood, tampons and pads in a Composting Toilet.

So first of all, for blood disposal, this can indeed go in the toilet.

It is treated the same way as urine (liquid)

Some women who use the cup, actually opt to dispose of their period blood in the garden, as blood is rich in nitrogen. It is also great food for houseplants.

In answer to tampon and pads, there seems to be a lot of conflicting opinions here.

The tampons, if made of 100% cotton, can usually be composted.

However, commercial types cannot always compost fully.

Pads should not be composted. Instead opt for a reusable pad such as the Wegreeco Bamboo Reusable Sanitary Pads. Some women find this very off putting, but it is not as bad as it sounds.

I simply wash the excess blood off in the basin, and then add the pads to my washing. Sorted!

How long does a Composting Toilet take to make compost?

This depends on what kind of toilet you are using, and also how many people are using it.

But a general rough estimate could be anything from a few months to a year.

How do you empty a Composting Toilet?

Again, this depends on the type of toilet that you have, but most toilets, especially those with a multi chamber design will have a finishing chamber whereby the waste will finish its process of breaking down completely. For toilets with a handle, it’s easy to tell when you need to empty it.

If it turns easily, it’s not ready to be emptied.

If the handle is hard to turn, then you need to empty it.

If you wish to break down the compost even further, then you can put it in a separate composting bin where it can do this. If it has broken down completely, then add it to your garden.

With the urine chamber, this needs to be emptied every few days, again depending on how many people use the toilet. (Please remember to check where you can dump urine waste in public areas!)

Can Composting Toilets handle diarrhea?

A lot of people wonder if Composting Toilets can handle things like diarrhea, and the answer is yes, it can. It is treated in the same respect as normal waste.

Obviously, there is a lot more liquid in diarrhea, but the toilet will do its duty at separating the bulk from the liquid.

Can Composting Toilets handle vomit?

Composting toilets can handle vomit as well.

Again, it’ll be more liquid than solids, but it will be treated the same way as normal faeces and urine.

Most of liquid will evaporate as it goes through and into the chamber, and any solids will be separated to be composted.

How do I clean my Composting Toilet?

There will be some small differences, depending on what kind of toilet you use, but for the most part, Composting Toilets need regular cleaning just like conventional toilets do.

The most important thing is to not use any harsh chemicals!

Instead use a cloth with warm soapy water or else an Eco-friendly toilet cleaner and just as you would for a conventional toilet.

Wipe all areas, like the seat, the tank, the bowl etc.

Another option for a cleaner would be to use equal parts of vinegar and water and wipe with a rag.

Remember there is no water in the bowl, so a wipe will do it!

Which is the best Composting Toilet?

Here are four of the best Composting Toilets that you can buy:

1.) My favorite one is the Nature’s Head Self-Contained Toilet.

It is very small and compact.

The seat is fully elongated for maximum comfort and comes with the vent hose and fan included.

There is a separate area for urine and a separate area for the solids. It is very easy to empty both the urine and compost chamber.

Can be used about 80 times before it needs emptying.

The one drawback with this toilet is that is that the holding capacity is quite small, so would be suited to no more than two to three people.

2.) The Sun-Mar Excel Self-Containing Toilet is a non-electric Composting Toilet and is really great for off grid lifestyles.

It is also bigger, and can handle larger families.

It also comes with two containers, one for liquid and one for solids.

3.) The Sun-Mar Centrex Non-Electric Central Composting Toilet.

This is a very good model and one of the best central systems that you can buy.

Central meaning that the compost chamber is in a separate space to the actual toilet.

This is usually below the bathroom or room that the toilet is in, or in an area on site but away from the living quarters.

It is quite expensive, but you will have no smell issues with this toilet and it’s easy to set up.

4.) An example of an electrical Composting Toilet would be the Sun-Mar Compact Self-Contained Toilet.

You will need power to run this toilet, but the good news is that it’s easy to set up and maintain, and needs nothing special in the way of wiring.

This is a smaller unit and will be suited to compact spaces.

What is the best Composting Toilet for an RV, Camper van or Boat?

Because limited space is an issue here, a Self-Contained Composting Toilet such as the Natures Head brand would be a good option for an RV, Camper van or a Boat.

Sun Mar also have a toilet that is suitable for RV use.

However, they are a lot more expensive, and a bit bigger in size, so if space is really an issue, then go for the first option.