Recipe for a DIY composting toilet

ingredients:

• 2 wheelie bins, pickle barrels or plastic drums.  I found two wheelie bins on the street in hard rubbish, and no I didn’t just steal people’s bins, they had cracks in them and a notice saying please take the bin.  You need two because when one is full and the material is composting, you need another one to be adding to.
• Milk crate, bakery tray and a piece of screen or plastic mesh (or anything you can find that will serve the same purpose).  This is to make a raised platform in the base of the bin so that liquids can drain through, so the compost pile isn’t wet and smelly.
• A piece of plastic plumbing (technical name) to attach a hose to the hole drilled at the base of the bin.  I used a tap from a broken brew kit in hard rubbish.
• Hose to drain liquid waste from the bin.
• Two pieces of irrigation pipe.
• Silicon sealant
• Small amount of gravel
• Bucket with lid – if you want to have an indoor toilet and empty the bucket about once a week.  This doesn’t smell or attract flies at all if the shit is kept covered with organic matter and the lid is on when it’s not in use.
• Toilet seat
• Coarse organic material to add carbon and aeration to the composting system.  This could be wood shavings, dry grass clippings, autumn leaves, shredded paper, rose petals, compost or whatever else is available.  A friend was using lavender flowers for a while.

Utensils:

Hacksaw, drill

Method:

Cut the milk crate and bakery tray with a hacksaw to make a raised platform about 5cm above the base of the bin.  Alternatively place bricks in the base and lay the tray on top.  cover with screen or mesh to prevent solids falling through the platform.

Cut the irrigation pipe to a length to fit diagonally inside the bin.  Drill small holes along the length of the pipe, plenty of them.  This is to allow air to flow through the pile as it is composting, to prevent it from putrefying (no-one wants that, it would be stinky).

Drill a hole in the side of the bin, as close to the base as possible.  This is for liquids to be drained out.

Attach a tap or plumbing bit into the hole.  There are bits available for this purpose, that seal in place with plastic washers. Otherwise use silicon sealant to prevent leaks.

Attach the hose to the tap, and bury the other end of the hose in the ground, surrounded by gravel, so that the liquids can drain.  This should be away from where vegetables are growing.  This liquid contains pathogens so should not be left on the soil surface.  If urine is kept separate most of the time the amount of liquid should be minimal.

Place a layer of bulking matter in the bin, small twigs or straw or something airy, and you’re ready to go!

You have a few options for the next bit.  You could build an outhouse around the bin, or put it in a shed or outdoor laundry with a squatting platform, and deposit directly into it.

Otherwise you could put a bucket in your bathroom and build a commode around it, or place a toilet seat directly on the bucket.  Some go even more low tech and simply squat over the bucket.

Add a handful of carbon material every time you go, enough to cover it.

When a bin is full, leave it to break down for 6months to a year, and then bury the compost under the ground.  It may still contain pathogens so it’s best not to leave it on the soil surface.  Adding compost worms can help with the composting process.  Unlike most people, they like nothing better than living in a pile of shit.  They tend to die during heatwaves though.

Urine can go directly on the garden. it is great fertiliser for the garden, it is high in nitrogen and contains all the nutrients that plants need.  By peeing in a flush toilet, we are not only wasting water, but a valuable resource.

Urine is sterile, so is not introducing any pathogens to the garden, and unless it is concentrated in one place, doesn’t create any smells.  Diluting it in water is recommended, as the high nitrogen content can damage plant roots.

Scientist James Lovelock hypothesises that urine is a result of a symbiotic evolution with plants, as we actually expend otherwise unnecessary energy to expel our wastes in a form that is readily available to them.

“it’s estimated that one person’s annual urine output contains enough soil nutrients to grow grain to feed that person for a year.  Therefore it’s … important to recycle urine…” (Jenkins 2005)

The naturalised ecology of Darebin Creek

While in Melbourne last year I had an opportunity to participate in a morning of tree planting, and found my eyes being opened to a whole new way of seeing and being.
The tree planting took place on the banks of Darebin Creek, an ideal site for a productive ecosystem. The creek banks had rich black soil, as a result of organic matter being washed down the creek. I’ve heard that creek banks in urban areas are now too nutrient rich to support native plants, so are more suitable for exotics with high nutrient requirements. The site was already home to a variety of self-sown useful plants.
A few fruit trees and herbs had been collected in the preceding weeks (apple, quince, elder, currant, mint, yarrow) all from suckers and cuttings gathered on public land and from friends’ gardens.
A small group who shared in the vision of urban food forests came along to help out. They arrived by bicycle and planted the trees and herbs. The plants were mulched with cardboard and dry grass that had been washed down the creek in the last flood. Some tree guards were found dumped nearby, and put to good use. The quality of the soil meant that there was no need to fertilise, and given the microclimate of the creek bank and the coming winter rains, the plants would not need watering. So after a couple of hours work we could leave the site knowing that the plants we had put in would not need any further attention, and in a couple of years time there would be fruit to be discovered and enjoyed by people passing by.
In the years to come, more plants will be added, the plantings will continue up and down the creek, and the area will become known as a community food forest.

This activity gave me a whole new understanding of the essence of permaculture – if we plant a tree in a location that it will naturally thrive, and create an ecology in which succession and interaction are optimised to benefit all elements of the system, then we need never do any work at all.
Another insight I gained from the morning’s activity is that there is so much unused land in our cities (creek banks, the edge of railway lines, road verges, nature strips and rarely-visited corners of parks) that no-one in the city ever needs to feel limited in their ability to produce food. Fruit and nut trees require little maintenance, can integrate into the existing city ecology, and can be taken care of by nearby residents.
And there is so much food already growing on all this apparently empty land, but the majority of us would never recognise it. Chickweed, nettle, plantain, good king henry, purslane, fat hen, marshmallow, black nightshade, cape gooseberry… and no doubt there are hundreds more I haven’t learnt about yet. These nutritious plants are under our feet everywhere we walk in the city. I’ve concluded that the reason we don’t value them as food is that they are not a commodity, and in our culture dominated by economic considerations, anything that is not being sold to us is not given any value.
In times past when people recognised these plants and spent more time outdoors, they would have picked and munched on them as they went about their day, getting large amounts of nutrients from small amounts of food. The reason there is so much obesity and malnutrition in the developed world is that our bodies are craving nutrients that are absent from the processed foods that form the bulk of our diet, while we actively destroy these ‘weeds’…
Which shows how much work we do that isn’t useful, and how little we value anything that hasn’t required someone to do lots of work.
There’s so much to be learnt from the trees and weeds.
Food for thought, food for the future.

planting on the banks of Darebin Creek