Each time you flush your toilet, a huge amount of nutrients is lost, along with fresh drinking water, only to become pollution for precious natural waterways. You can avoid all of this by managing an effective human waste composting operation, and the end product is a rich and safe fertilizer for the plants in your garden.
Benefits:
- Creates fertilizer
- Saves nutrients
- Saves water
- Saves the world!
Materials:
- 8 x pallets (single-use)
- 4 x 20L plastic buckets with lids
- 1 x toilet seat
- Scrap wood for making a humanure toilet (composting toilet)
- A regular source of straw/hay/grass clippings
- A regular source of sawdust
About Human Waste
Human waste (affectionately known as ‘humanure’) is a resource that is overlooked. Our feces and urine combined contain enough nutrients to grow all the food we need to survive. Combining human waste with sawdust, kitchen scraps, weeds and prunings in a compost bin can generate enough heat to destroy human pathogens and compost the material, turning it into something new – rich organic fertilizer.
About Human Pathogens
As humans have existed for thousands of years, certain bacteria, viruses, protozoa and worms have developed alongside us, tailored to suit conditions inside our bodies, where they breed and lay eggs, and make us horribly sick.
It’s interesting to note that they can only get from one person to another through contact with human waste. This means that for thousands of years we have been mismanaging our waste, enough for these human pathogens to develop and survive.
Our current answer to the problem of human pathogens is to flush our waste, along with crystal clean drinking water, into a sewer system, where it mixes with anything and everything that is poured down drains and washed off roads, to a waste treatment facility, where toxic chemicals are mixed with the polluted water to kill off pathogens, and the finished product is pumped into rivers and oceans for aquatic creatures to deal with!
A better answer is for our waste to be collected from our homes and taken to a large-scale composting facility, where the natural activity of bacteria and fungi compost the material, destroying pathogens and creating rich fertilizer. Until such an operation is in place, managing your own human waste composting operation is the most sensible and responsible option, and it’s just as effective.
Sourcing Materials
- 8x pallets (single-use) – Single-use pallets can be found outside many shops, especially gardening shops and hardware stores. They should be untreated with no paint, and if you ask, they should be free to take. Choose ones of a similar size, so they can fit together well to form your pallet-style compost bins.
- 4x 20L plastic buckets with lids – These are also called pails, and can be found in many places for free, or purchased from hardware stores, fishing stores, and department stores. Builders and painters use and throw away heaps of them. Keep an eye out for skip bins at building sites. It’s important that you get at least 4 buckets exactly the same, all with lids. Your humanure toilet will need to fit them exactly.
- 1x toilet seat – Any toilet seat will do. If you’re planning to decommission your flushing toilet, take the seat from that.
- Scrap wood for making a humanure toilet – Your humanure toilet is just a box with a hinged lid. It’s easiest to make out of wood, but any material can be used – even an old chair can be retrofitted!
- A regular source of straw/hay/grass clippings – This needs to be used as cover material for your compost piles. It is essential, but can be hay/straw, grass clippings or leaves (finer is best). If you have chickens, you’ll probably have a regular supply of hay/straw anyway, and the compost will benefit from the extra manure.
- A regular source of sawdust – This is used as a cover material in your humanure toilet. It is best sourced from a local timber mill – where fresh logs are cut into planks. Sawdust from hardware stores is not suitable – it is sterile and contains treated wood sawdust which is poisonous. If you can’t get your hands on a regular supply of fresh sawdust, consider using ground newspaper or leaf mold.
How to Make a Compost Bin with Pallets
Pallet-style bins can be as simple as 4 pallets tied together, but here’s a way to make one that’s easy to work with. You will need 4 ‘stringer’ pallets for this construction. (stringer pallets have lengths of wood holding the slats together, whereas ‘block’ pallets have blocks of wood. You will have to modify the design if block pallets are all you can find.)
- Step 1: Dismantle one of the pallets, keeping pieces intact. You will need the slats to build up the last wall of the bin, and the ‘stringers’ (the thicker lengths of wood) to make rails for the slats to slot into. Dismantling is easiest done with a claw hammer and chisel/screw driver.
Dismantle the pallets. Be careful not to trip over your daughter's bike while you're at it. - Step 2: Remove any slats from the bottom of the other 3 pallets.
- Step 3: Clamp the back and side pallets together, such that the back pallet is tucked inside the sides.
- Step 4: Take two of the stringers from the dismantled pallet, and clamp them parallel to the stringers on the side pallets, with enough room between them to allow slats to slot in without getting jammed.
Slide the planks in. Don't forget your pink Crocs. Safety comes first! - Step 5: Drill holes and screw the pieces together. Slot slats in and build up the front wall, to find out how many slats you’ll need to complete the bin.
- Step 6: Unscrew the pieces. At this point I recommend coating all pieces with raw linseed oil, to preserve and weatherproof the bin. Each bin will need to last at least 2 years in the weather with all manner of decaying material inside them. Collapse is possible if you’re using softer woods prone to rotting. Raw linseed oil is a natural oil which dries to form a waterproof barrier. Coat pieces thickly and leave at least a day to dry.
- Step 7: Prepare the site for your new pallet-style compost bin. It should be level.
- Step 8: Re-assemble the compost bin on the prepared site. I recommend propping it up off the ground with bricks in each corner, to further reduce the chance of rotting. Slot one of the slats in to start the front wall, and store the others somewhere handy.
How to Make a Humanure Toilet (Composting Toilet)
A humanure toilet is a receptacle designed only to collect human waste in buckets for composting later. Human waste is not composted in the buckets, only collected and stored. There are many examples of unique designs for humanure toilets, and one can usually be made using scrap materials you already have. The size of your buckets will determine the dimensions of your toilet. It’s important that your buckets are all the same size, and preferably a popular size so you can easily get more if you need to.
- A simple box can be constructed, large enough to accommodate one of your buckets, with a hinged lid that your toilet seat can be fixed to.
Make a simple frame for your bucket and toilet seat - A hole must be cut in the lid which matches the diameter of the top rim of your buckets, so that the rim can fit inside the hole nicely.
- The height of the toilet should be such that on level ground, your bucket will stick up through the hole in the lid.
Draw and cut out a hole. Make sure it allows your bucket to fit through it.
Screw the seats on - The toilet seat should be fitted so that it sits nicely over the hole. There should be no opportunity for urine to get between the bucket and the toilet and escape the system.
Loaded and ready for action!
How to Use a Humanure Toilet (Composting Toilet)
Sprinkle some sawdust to help eliminate the turdy odor
A humanure toilet is used in the same way as a regular toilet – all human waste and toilet paper is collected in the bucket. However, instead of flushing when you finish, a scoop of sawdust is thrown in to cover the waste. It’s a simple habit to get into, and odorless if you use a correct amount of sawdust.
The sawdust has two functions. It covers the waste, blocking odors, and it brings to the mix a high carbon component. Feces and especially urine are ‘nitrogenous’ material, which, in composting terms means that it provides bacteria with nitrogen for building proteins and reproducing. ‘Carbonaceous’ materials, such as sawdust, provide bacteria with energy. A good mix of the two is a recipe for rapid hot composting.
When a bucket is almost full, the lid of the humanure toilet is lifted, the lid of the bucket is secured, and the bucket is replaced with an empty one. Full buckets can be stored for weeks before composting with no problems. If you decide to stick with just the 4 buckets in your system, I recommend emptying them 2 at a time. If you’ve got a large family I recommend additional buckets and emptying 4 at a time.
Make sure you have enough sawdust to keep the air fresh
When an empty bucket is placed in your humanure toilet, I recommend adding a few scoops of sawdust to coat the bottom. This helps to ensure all material comes away later when you empty your buckets into the compost pile.
How to Start a Humanure Compost Pile
Once you’ve filled two or more buckets using your humanure toilet, you can begin composting the material, along with your kitchen scraps, weeds, prunings, newspapers and cardboard.
- Using a shovel, scrape into the ground at the center of your bin, and create a dish
shape. Throw the excess soil up around the edges to further expand the dish. The idea is that if any moisture should leach out from the bottom of the pile, it will concentrate and absorb here, rather than flowing out and off the site. - Spread a thick layer of hay/straw/grass clippings in the bottom of the bin, at least 45cm thick. This material acts as a sponge (soaking up moisture that might otherwise leach), and allows air to penetrate the pile from below.
- Add a layer of weeds and prunings, newspapers (shredded) and plain cardboard (shredded).
Add kitchen scraps and any other compostable materials at this stage. - Empty your humanure toilet buckets into the center of the pile. The consistency should be sloppy but not runny (if it’s runny you should’ve added more sawdust!), and the weight of the material should sink it down into the center nicely. You may wish to hold your breath at this stage – it is the only part of the operation where you may encounter bad smells.
- Cover the pile with a fresh layer of hay/straw/grass clippings, thick enough that the
pile is not producing any bad smells. - Rinse your buckets, using a bit of biodegradable soap, water and a dedicated toilet
brush. Use the same water from the first bucket to rinse the second and third, and then pour the water into the top center of the pile, adding a handful more hay/straw/grass clippings to cover this spot.
Your humanure compost pile is now started, and the materials should heat to at least
38degC (100degF) within a few days.
38degC (100degF) within a few days.
How to Add to a Humanure Compost Pile
Try asking your friends, neighbors, or gardeners for some straw/hay/grass clippings
It’s important to maintain a layer of hay/straw/grass clippings completely surrounding the
composting material; on the bottom, sides and top of the pile. This both insulates the pile – retaining warmth, and prevents evaporation the same way mulch does. It also prevents material falling out of the bin! Keep this in mind as you add to your piles.
composting material; on the bottom, sides and top of the pile. This both insulates the pile – retaining warmth, and prevents evaporation the same way mulch does. It also prevents material falling out of the bin! Keep this in mind as you add to your piles.
- Using a dedicated pitch fork (used only for your human waste composting operation), scrape the hay/straw/grass clippings from the top center of the pile to the sides. You shouldn’t have to dig into the pile to do this, just gently comb it back against the walls of the bin.
- Using the fork, dig into the top center of the pile, pulling material back toward the walls to create a hole in the center. Make sure nothing leaves the bin. If you add to your pile on a weekly basis, you should notice some heat in the center. It’s the heat which destroys pathogens, and it’s into this heat we dump our fresh material.
- At this point you can add any kitchen scraps, weeds, prunings, newspaper (shredded) or plain cardboard (shredded). Ensure the hole is big enough to accommodate all of your fresh materials.
- Empty your buckets into the hole. As always, the consistency should be sloppy but not runny.
- Add a layer of hay/straw/grass clippings until all odors are blocked.
- Rinse your buckets, using a bit of biodegradable soap, water and a dedicated toilet brush. Use the same water from the first bucket to rinse the second and third, and then pour the water into the top center of the pile, adding a handful more hay/straw/grass clippings to cover this spot.
- I recommend adding a few scoops of sawdust to each of your buckets, replacing the lids and shaking them, so the sawdust is dusted all around. The sawdust absorbs moisture and residual smells.
Allow yourself about 30mins to complete this task. Take the time to do a thorough job, and make sure no waste leaves the system. With practice, it may only take you 15mins.
Allowing Compost to Age and Cure
Human pathogens are destroyed in minutes in a hot compost pile (50degC [122degF] or above), and while a compost thermometer can measure the general temperature of the pile, it’s hard to be sure that all materials have been exposed to these temperatures, which is why a human waste composting operation must involve a retention period, during which the pile is left to age and cure for a year before it is used.
Pathogens cannot survive so long outside a human host.
With both measures in place, your human waste composting operation is a responsible one, and the resultant compost is safe for use in the garden. Once your first humanure compost bin is filled, start a new one, and leave the first alone for a year. Since it takes a family of 4 about a year to fill a bin, using two bins in rotation should be all you need.
- After the one-year retention period, the material in the first bin will have shrunk a little, but from a pallet-style bin you should have about 1 cubic meter of rich compost, ready for use in your garden.
- Remember that your finished compost is something completely different to the waste and other materials you originally added. It has been consumed by bacteria, fungi, worms and other bugs, all of whom have contributed to the composting process, converting it to something new.
Using Your Compost
After leaving your first full bin for a year, it is ready to use. Grab a wheelbarrow and shovel, and start digging the compost out of the bin, removing slats as you go.
Spread compost around the base of trees, in vegetable gardens, even over lawn. It can be dug into the soil or mulched over. After only a few years of application, your soil will be rich in organic matter, sustaining life, retaining moisture and nourishing anything you wish to grow.
Using a Compost Thermometer
I recommend purchasing a compost thermometer to monitor temperatures in your humanure compost piles, especially when you are starting out, and experimenting with what you’re adding to your bins.
Compost thermometers have a long skewer which penetrates right into the center of the pile. They are waterproof and, if handled properly should last you a lifetime. After adding material to your humanure compost pile, stick your compost thermometer into the top center, right down until the dial is just above the surface. This will give an accurate reading.
As you experiment with different amounts of kitchen scraps, weeds, prunings, newspapers and cardboard, your focus should be on achieving temperatures 50degC (122degF) or above.
Don’t panic if your pile doesn’t reach these temperatures as you begin; keep experimenting until you find a ‘recipe’ that works.
Why compost human waste?
Flushing our waste down the toilet is the start of a costly process which ends in the pollution of waterways and oceans. Composting human waste is a simple and practical way of taking responsibility for ourselves. It’s regenerative too, which means it encourages life and soil fertility.
Are there any smells?
There are no smells in the use of a humanure toilet, as the deposits are covered with sawdust which traps odors. There are no smells from a human waste compost pile, as the pile is surrounded and covered with hay/straw/grass clippings, which traps odors. The only smell encountered is when buckets are emptied into the pile, before the pile is re-covered. This is a short period of time – about 5 minutes.
Isn’t it dangerous?
Human feces can carry human disease-causing pathogens. A well-managed human waste composting operation will destroy pathogens in minutes, and just to be sure, the compost piles are left to age for a year after filling – too long for pathogens to survive outside a human host.
Is it legal?
As we are slowly changing our attitudes toward recycling human waste, more and more commercial composting toilets are being approved. Check with your local authority whether or not your system can be approved, and consider all risks before you launch.
Will flies be attracted?
Flies should neither be attracted to a composting toilet, nor to a humanure compost pile, as there are no smells produced to attract them. If flies do hang around, it is an indicator that not enough cover material has been added – just add more!
What about pet poo?
Dog and cat feces potentially brings with it a host of other pathogens, some of which can infect humans. While I’ve read of people practicing mixing pet poo in with their human waste, I have yet to read of studies concluding it is safe. I recommend either having a separate compost pile to manage pet poo, or bury it in an isolated area of your yard, away from animals and children.
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