How Does a Compost Toilet Work? Understanding All Its The Aspects


Nature has a unique way of handling processes. Typically, many people are used to the kind of toilets that use flush mechanism as a way of disposing of the waste.

But if by chance you ever find yourself living in a relatively small room or even in municipalities where the septic systems are a bit expensive or unavailable, just know that there is always an option. All you need to get is a composting toilet.

how to use a composting toilet
how to use a composting toilet

It can be a little bit difficult to understand perfectly how a waterless loo can actually be able to handle and decompose human waste. Considering that it also stays odorless, which is so unique.

If you’re wondering how possible this could be, just know that you’re in the right place. In this article, I will discuss all the fundamental aspects regarding a composting toilet.

So that the next time you think of having it, you also understand in detail how it works and other related aspects.

Now let’s get down to business and look at all the essential elements of this kind of lavatory.

So What is a Composting Toilet?

Presumably, you have seen or used one before. But if you haven’t, just know that this is a type of toilet that utilizes a natural process to treat and break down human waste.

It can be described as an alternative sewage treatment mechanism that decomposes feces on-site and converts into compost that is often used for gardening and soil amendments.

You do not need water to flush the poop into city sewerage or septic system or when using this toilet.

In fact, what you mostly need after finishing pooping are a wide range of carbon additives, depending on the manufacturer.

It is necessarily a type of latrine that bio-chemically decomposes the organic matter (in this case is human waste and other plant products) by using aerobic organisms.

Aerobic organisms are simply the types of bacteria that can be able to obtain oxygen from the atmosphere and also emit carbon gases.

And for that reason, you’ll hear other people referring to it as a dry toilet. Yes because it uses no water.

This type of toilet mainly uses a similar concept like one that takes place in a backyard composting pit.

Given that it relies on aerobic bacterial activity, it is vital to ensure that an ideal environment for these micro-organisms is created. This allows the bacteria to break down the waste efficiently.

Components of a Composting Toilet

If perhaps you intend to use this type of latrine for the first time, this is apparently what you’d want to know.

This lavatory entirely utilizes a biological process that you’ll find so interesting. But first, you have to know that these toilets have to be designed with particular components that allow them to attain the desirable results.

The main parts are two; sitting/squatting part and the collection/composting unit. The sitting/squatting section is merely for enabling you to get a better position and comfortably empty the bowels when using

The collection/composting unit, on the other hand, is what plays a significant role in the entire decomposition process. It is made of four major sections, which include the following;

1. Storage/composting chamber

This is the particular area where the wastes are reserved immediately after dropping. This is the compartment where the poop falls awaiting decomposition process.

But mainly, it serves as a space for the productive natural break down for both urine and human waste and converting the same into stable organic compounds.

Most manufacturers often design it somewhat in a slope-shape so that it becomes easy for it to separate urine from the solid waste.

2. Ventilation Unit

It is primarily designed to help in enhancing the degradation process. This is in the sense of making the toilet predominantly aerobic such that it can be able to let go of the malodorous gases naturally.

3. Leachate management mechanism

This is primarily designed to allow for the quick elimination of excess liquid that might end up mixing with the wastes.

The essence for this is to create an ideal environment for bacterial activity for a faster rate of decomposition.

Then there is an access door that is used for extracting the waste that has already been decomposed. This access door makes it easy for you to remove the compost after the entire natural decomposition process is over.

What It Takes for Decomposition to Happen in Composting Toilet

From the design and the components, you ought to realize that this particular type of lavatory does not allow for any form of liquid waste to mix with solid waste in the composting chamber.

Ordinarily, you’ll realize that 90% of human waste is made of water, which apparently, tends to evaporate rather fast.

Depending on each manufacturer, some are designed in such a manner that allows the urine to divert from the composting chamber. This enables it to evaporate relatively fast to the air through the vent system.

In some designs, the environmental elements such as sun and wind are used as catalysts for evaporating the urine content. Such are known as passive composting latrines.

In other cases extracted when full whereas other units are fitted with a particular electric system that heats up the liquid waste. This is intentionally designed to hasten the evaporation process for faster decomposition.

However, it is also essential to understand that whereas the evaporation of the liquid waste in the toilet is vital, the compost should not be entirely dry.

For relatively faster and natural decomposition process to take place, it is vital for the compost also to remain a little moist.

For this eco-friendly toilet to work efficiently and break down all the solid part of the human waste, four fundamental components must be in place and also well balanced.

Necessarily, these four elements include moisture, oxygen, aerobic bacteria, and heat.  That’s what enhances faster and efficient decomposition process in these toilets.

As long as these four elements are available in right proportions, the mixture of feces, toilet papers, and other additional organic plant components will be able to decompose naturally.

When the entire decomposition process is over, the finished product of the composted mixture commonly known as humus or humanure is formed.

Understand How Does a Compost Toilet Work

The urine moves by gravity to the deepest part of the composting chamber. The aerobic bacteria present are then engaged in an action that sees them convert the urine into a liquid that is rich in nitrogen.

When the urine and solid waste separate, an ideal environment is created for enhanced activity of aerobic organisms. Such organisms include bacteria, fungi, compost worms and insects among others.

Furthermore, continuous separation of urine from poop is also essential when it comes to the need for preventing possible lousy smell.

Because if you fail to keep the two separate then the process will become anaerobic, and that’s where the odor emanates from.

It is these organisms that slowly but actively break down the human waste, still at the composting chamber. It is here where the waste is converted into dry compost material.

For faster decomposition process, the right amount of carbon materials is also added. These include elements such as sawdust, paper, wood chips, ash, straw, and earth among others.

The trickiest aspect of the entire process is balancing all the four fundamental elements to the required levels.

Getting the balancing act right also significantly depends on how the manufacturer of the particular model integrate it.

Some manufacturers tend to use the manual agitators as a way of aerating the waste in the composition chamber. This helps in maintaining the required levels of oxygen.

Others, however, come with a different composting bin that keeps the chamber oxygenated and aerated by rotating it whenever there is a need to.

Also, some brands as I’d earlier described, use electric heat system to maintain the required temperature suitable for keeping the aerobic bacteria activity optimum all the time.

Other also use natural ventilation mechanism to provide warmth across the decomposing mixture. So it all depends on a specific manufacturer.

The dry compost material, which is the end product is more or less similar to the topsoil from the perspective of chemical composition, biologically and appealingly.

The ultimate dry product also contains various plant nutrients and can be used for gardening or backyard fertilizing.

Duration a Bio-Toilet System Takes to Decompose

Several variables determine how slow or fast the decomposition process can take place. Simply put, a lot of factors come into play hence tricky to precisely tell the duration the process takes.

Let’s have a look at a few of these aspects;

Number of users

What happens is that the decomposition process in a bio-toilet depends on the number of people that are often using it.

If the number is relatively high, the process will be a bit slow compared to when the users are few.

Again, more users would also require that balancing of all the four fundamental elements be done appropriately to prevent cases that would lead to anaerobic and eventually bad smell.

Volume of waste it can take

Another aspect is that different compostable toilets are designed to handle the various capacities of waste.

Some will generally take more time until the optimum level is attained, whereas other will typically take shorter time when the quantity is manageable.

So it all depends on the design hence appropriate to ensure that you consider this particular element when shopping for this kind of toilet.

Electric or non-electric

Probably some of you have a question in your mind “how much does a composting toilet cost?“. Let’s start by discuss the electric usage.

Electric waterless composting toilet works at a somewhat rapid rate than non-electric. The thing is that it is easy to regulate electric units especially from the aspect of temperature adjustments.

Non-electric units, on the other hand, may take more time to accomplish the decomposition process given that most of them depend on natural conditions to facilitate the breakdown of wastes.

Electric can be costly to acquire but depending on your preference may offer best results in terms of overall duration taken.

Balancing of the four elements

As I had earlier mentioned the levels of oxygen, heat, moisture and aerobic bacteria have to balance. It is the most significant of not only the duration but also the end dry compost product.

If any of these elements do not balance accordingly, the chances are high that it will take comparatively long time.

Also, the composted manure at the end of it will not necessarily be nutrient-laden for the gardening or even soil enhancement.

Design of the toilet

The model also affects the duration that wastes can be decomposed. This, however, narrows down to the particular manufacturer.

Some design their units to suit long-term decomposition process. The reason for this is that not everyone is necessarily interested in undertaking the monitoring and extraction processes on a routine basis.

But if you’re perhaps into camping or just any kind of outdoor activity, the ideal choice you’ll need is one that requires short-term decomposition process. Given that you will not permanently stay there for long.

But when all factors considered, it takes approximately 60-180 days to have an excellent, nutrient-laden dry compost out of human waste using a composting toilet.

What Makes the Composting Toilet Eco-Friendly?

Understandably, the wastes from this particular type of toilet are not typically disposed of merely as wastes, which could potentially degrade the environment.

Instead, they are disposed of a decomposed component, rich in various elements that are ideal for the soil, mainly used for gardening.

In that regard, it means that no water is wasted in disposing of the human waste. We all know that toilet can use a large volume of water and if everyone has to use it in flushing the waste then it can be disastrous to the environment.

The conventional sewer lines use chemicals as a way of recycling and preserving the content. The compounds, in the long run, hurt the environment and humanity in one way of the other.

What happens with bio-toilets is that they hardly use chemical substances. It thus makes them eco-friendly and harmless to the humanity too.

Whether or not to use compost toilet by-product in farming is highly dependent on where you reside. Primarily, in some cities, the use of dry compost humanure is prohibited.

It, therefore, means that you need to find out from the relevant authorities within your municipality to determine if it is permitted to use.

The bottom line, however, is that you need composting toilets are the better alternative if you are living off-grid, travel for outdoor activities often and most importantly, environmentally conscious.



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