Wheelie bins, trash cans or garbage cans with wheels. Whatever you call them, they are an excellent option for building your composting toilet!
Building a wheelie bin composting toilet is a great way to reduce waste and create nutrient-rich compost for your garden. It is cheap to do and completely achievable with a few tools and handywork. In this article, we will guide you through the process of building and maintaining a composting toilet using a wheelie bin.
Table of Contents
Introduction
What is a composting toilet?
A quick recap on what a composting toilet actually is, and therefore what you are aiming to achieve with your wheelie bin composting toilet.
A composting toilet is a type of toilet that converts human waste into compost through a natural decomposition process. We call this product humanure. It is an eco-friendly alternative to traditional flush toilets and can be used in both urban and rural settings, subject to your local regulations. The composting process uses no water, other than for cleaning, and allows you to take control of your waste management.
Composting toilets align closely to the principles of permaculture since they give you the opportunity to use your waste for productive purposes such as increasing soil nutrients and plant growth.
Benefits of using a composting toilet
There are several benefits to using a composting toilet. Firstly, unlike flush toilets which use excessive amounts of water, they help to conserve water as there is no requirement for flushing. This is why we are so interested in them here at Every Drop Saved. Secondly, they are self-contained and do not require any connection to municipal plumbing. They allow you to become self-sufficient! Lastly, they produce a valuable compost that can be used to enrich the soil in your garden. If you are growing food, think of it as ‘closing the loop’. You are growing the food, in part, with the waste you produce.
Why build your composting toilet from a wheelie bin?
Wheelie bins are readily available and just happen to be the perfect solution for DIY composting toilets.
Using a wheelie bin as a compost bin in your system is a cost-effective and accessible option. Wheelie bins are very common and can be easily modified to create a functional composting system. They also provide sufficient capacity for composting and can be conveniently emptied when needed. They are typically much bigger and more appropriate than a bucket and they have wheels, allowing you to wheel away the solid, composted material for disposal or placement on the garden.
We typically recommend building two or three wheelie bin systems so that you can swap them when they are full and place them somewhere to complete the decomposition process. The cooler the climate the slower the process, the more you will need.
Building the Wheelie Bin Compost Toilet
Selecting a suitable wheelie bin
The first step in building a wheelie bin compost toilet is to select a suitable bin. It should be made of durable material and have a secure lid with a sturdy hinge mechanism. We recommend picking the largest capacity possible that can be accommodated in the space under your pedestal. 240 litres, or 63 US gallons is a good size, go up and down from there depending on the available space.
Remember also that the larger the wheelie bin capacity, the more composting material it will hold, and therefore the heavier it will be to move around when you need to swap bins. A heavy bin system is fine, so long as you have good access.
Modifications needed for a composting toilet
This is the fun bit! To convert the wheelie bin into a composting toilet, you will need to make a few modifications. These include:
- Cutting a hole in the lid which will fit perfectly a riser pipe which will meet the underside of you pedestal in the toilet room above.
- Installing a drain-pipe at the bottom of the wheelie bin to allow liquids (urine) to drain away. You can do this with common plumbing fittings from your hardware store. Usually, a 1 inch ball valve at the lowest point in the bin, connected to a garden hose fitting is suitable
- Installing slotted PVC pipe, or ag-pipe from the base to the top of the wheelie bin. It is best to install one 4-inch pipe, vertically, in each corner of the wheelie bin. The bottom of the pipes will be open inside the base of the wheelie bin. The top will sit just under the lid of the wheelie bin. These pipes allow air to be introduced to the bottom of the compost pile.
- Installing a false floor. This will be a piece of rigid mesh screen which will sit around 4 inches above the base of the wheelie bin above the drainpipe and slotted pipe ends. The mesh size should be small enough to hold your composting material above it, but large enough to allow free draining to the bottom of the bin.
Ventilation
Proper ventilation is essential to ensure that the composting process is effective and to prevent any unpleasant odors. You can achieve good ventilation by either:
- Drilling small holes (say 1 inch diameter) in the sides of the bin, around the top, and above the compost pipe.
- Installing a vent stack with a 4-inch PVC pipe which extends above the toilet building to vent odors. It should have a U-Bend at the top to avoid rain getting in. It should also be inserted through a hole in the side or lid of the wheelie bin, above the compost pile, so that it can be easily disconnected when you want to change the bins over.
Option 2 is a better option for avoiding unpleasant odor in the toilet area. It is more work but our recommendation.
Drainage of liquids
It is important to allow for the drainage of liquids (urine) from the compost pile. This ensures an effective compost process and minimises odor.
This can be achieved by installing a drainpipe, as discussed above, in the base of the wheelie bin. You will want a screen on the inside to prevent blockage. This can be done with a simple mesh fabric placed over the drainpipe inside the bin.
The toilet pedestal and seat, and connection to the bin
The toilet pedestal is the part of the composting toilet that connects the toilet seat to the bin. It should be sturdy and securely attached to the bin to ensure stability and comfort. You can buy a pedestal that suits a composting toilet arrangement, or you can DIY it by simply building a wooden box with a toilet seat on it.
It is important for many of us to make a comfortable space within our toilet room, to do the business. And why not! What is below the space is purely functional, but what is in the room must also be comfortable and aesthetically pleasing. So long as you connect the toilet seat to the wheelie bin effectively, you can be creative with this.
Typically, we recommend screwing a piece of ducting pipe around 8 inches diameter, vertically, into the pedestal (or wooden box). This pipe should be inserted into or sit just above the wheelie bin lid. It is best to seal the connection with a piece of rubber. You can use tire inner tube rubber for this cut to size. You’ll need to build it such that you can easily remove the wheelie bin when its time to swap it over.
Composting Process and Maintenance
Setting up an efficient composting system with organic material
To make a compost toilet work effectively, it is important to layer the compost heap with organic material. This is typically sawdust, leaves, used coffee grinds, even kitchen scraps. This will help create the right balance of carbon and nitrogen needed for effective composting.
When you put a fresh bin in place, add a little of your dry organic material in the base. This will both kick-start the process, prevent your human waste ‘caking’ on the base of the compost bin, and absorbmoisture and odor.
Keep a bin of sawdust or leaves in the toilet room and each time you use the toilet, add a handful.
Maintaining the compost temperature and moisture levels
Monitoring the temperature and moisture levels of the compost pile is important for successful composting. The ideal temperature range for composting is between 100°F and 120°F (40°C and 50°C), and the moisture content should be similar to a damp sponge.
A healthy composting process will generate its own heat due to the microbial activity. This will help to drive the process along. But if you are in a cooler climate, it may just take a little longer to fully compost down. The solution to this is more wheelie bins that you can swap out when they are full, allowing off-line ones to fully compost.
Managing pathogens, insects, and odors
Managing pathogens, insects, and odors is essential for maintaining a healthy composting system. If the system is working well, there will be no issue with any of this. If things start to go a little wrong, for example if the drain blocks and it fills with urine, or if the venting system becomes blocked, these will may notice odor and insects.
Keeping the system maintained and orderly will prevent issues. Also, adding compost worms can helps to break down the waste a little faster.
Also, you are of course managing human waste and whilst this can be done safely with proper design and maintenance, there may be pathogens which could be harmful to your health. Try not to handle the compost material until you are sure it is full composted down. And remember, always follow the local regulations.
Swapping the wheelie bins
Once the first bin is full, it is time to swap it with an empty bin. This allows the composting process to continue undisturbed while the full bin can be left to decompose further. If you are in a cooler climate, and depending on how many people use the toilet, you may need two, three, or even four wheelie bins, on the ready to swap out.
Store the off-line bins somewhere out of direct sunlight where they can be left for a number of months. From time-to-time you may want to check progress of or your compost, and turn over the maternal with a garden fork.
Allow time for complete composting
Composting takes time, and it is important to allow the compost to fully decompose before using it. This can take 6 to 12 months, depending on the composting conditions. This will vary depending on your system and location and you should monitor the first ones to see how long it will take.
Applying compost to garden beds or fruit trees
Once the compost is fully decomposed, it can be applied to garden beds or around fruit trees to enrich the soil and promote healthy plant growth. Remember to use mature compost and avoid directly applying fresh human waste to edible crops. Uncomposted material is both detrimental to your plants and can be a serious health risk. Again, follow the local regulations.
Alternative Composting Toilet Systems
Proprietary systems
If building a wheelie bin composting toilet is not your thing, there are plenty of great proprietary composting toilet systems available on the market. These systems offer more advanced features and may be suitable for those looking for a convenient and low-maintenance option. We have a great article giving our recommendations on these systems, Best Off Grid Composting Toilets. A 2023 Review.
We’re also excited to be partnering Shop Tiny Houses who can provide any specific assistance you require on their products, and to purchase your new composting toilet.
Happy composting!
FAQs
Q: What is a wheelie bin composting toilet?
A: A wheelie bin composting toilet is a type of outdoor toilet that uses a wheelie bin as the main structure for composting human waste.
Q: How does a wheelie bin composting toilet work?
A: A wheelie bin composting toilet works by separating and composting human waste in order to turn it into a sustainable waste product. It utilizes a bucket system and aerobic composting to break down the waste.
Q: What are the benefits of using a wheelie bin composting toilet?
A: Some benefits of using a wheelie bin composting toilet include: reduced water usage, reduced strain on septic and sewerage systems, the ability to turn humanure into a nutrient rich compost, and the opportunity to practice permaculture principles.
Q: Can I build a wheelie bin composting toilet myself?
A: Yes, you can build a wheelie bin composting toilet yourself following the guide in this article. There are also various other online resources, including videos and guides, that provide instructions on how to build one.
Q: Do I need council or government approval to install a wheelie bin composting toilet?
A: The need for council approval may vary depending on your location and local regulations. It’s important to check with your local council to determine if any permits or approvals are required.
Q: What materials do I need to build a wheelie bin composting toilet?
A: To build a wheelie bin composting toilet, you will need a wheelie bin, some PVC or ag-pipe, a piece of larger diameter ducting pipe, some basic plumbing materials, a toilet seat and a pedestal arrangement. You’ll also need various tools such as a saw, drill, and screws.
Q: Can I use any type of wheelie bin for a composting toilet?
A: You can adapt your design to suit any size and type of wheelie bin. We recommend going as large as possible, within the space you have available.
Q: Is it safe to compost human waste in a wheelie bin composting toilet?
A: When properly managed and maintained, composting human waste in a wheelie bin composting toilet can be safe. The composting process, including the heat generated, helps to break down pathogens and minimize any potential risks.
Q: How do I turn humanure into a sustainable product with a wheelie bin composting toilet?
A: To turn humanure into a sustainable product, the composting process in the wheelie bin toilet should be maintained properly. This includes ensuring proper aeration, managing moisture levels, and allowing sufficient time for decomposition to occur.
