I’ve been a fan of composting toilets for decades now. There’s just something about NOT shitting in drinking water and making quality composting for my landscape with my own humanure that just makes me feel really good and really smart.

I’ve also long been into making compost toilets myself in both rental properties and now our own home. We’re still connected to the mains sewer but we have an outhouse for our 20L bucket system which works a treat. I’m not against store bought compost toilets at all – I love them. I’ve just found that it’s quite easy to make them yourself (when you know how) and cost significantly less. Here’s our compost toilet which Anton whipped up for us. I love it.

But first, do I think everyone should make their own compost toilet?

No. I’ve spent years studying and learning about composting, soil health, agriculture and composting toilets and am very clear on how to “do them right” to prevent any health concerns. If you’re not clear and comfy – don’t do it. And of course, check in with your local Council and/or authorities – I’m not endorsing anything illegal. I’m endorsing folks to think more broadly and to open their minds to changing their brains to what waste is. As musician and permaculture practitioner, Charlie McGee says “there’s no such thing as waste, just stuff in the wrong place“. And I agree.

We have two 20L buckets beneath a timber framework that lifts up on hinges so we can remove buckets as needed. One of them stores sawdust, or other fine carbon materials like shredded mulch/bark or rice husks. The other bucket is the toilet where you poo. Each time you do a poo, you cover it with a large handful of sawdust. This eradicates any smell, prevents flies from coming in and create the carbon input for the composting process to begin.

What happens once the bucket is full?

Once full, we empty the bucket into a nearby wheelie bin that’s been retrofitted for this purpose. We’ve turned them into a large compost worm farms, complete with a false floor and tap for drainage (more on that soon). But first – compost worms (Eisenia veneta), sometimes called Red Wrigglers are not your common earthworms, who hate strong nitrogen-rich environments. In contrast, compost worms looooooove nitrogen and thrive in this type of space. Once the wheelie bin worm farm is full of humanure and sawdust, we leave it for 12 months. During this time the compost worms eat through the entire contents, transforming it into worm castings. Once this process is complete we empty the whole lot out onto our perennial edible gardens. The main thing we have to keep an eye on during this 12 month period is that it tends to dry out. So in warmer months I check on the worm farms monthly and do a small hand water if needed to maintain some a moist environment.

What about urine?

We don’t use this system if we JUST need to urinate, instead we either urinate in our flush toilet, on the grass or, if I want to harvest it into a separate bucket. If I’m doing the latter then I dilute it with water 10:1 and put it onto our edible perennial gardens as a fertilsier. Urine is actually far superior than humanure as it has a high ratio of nitrogen, phosphorous, potassium (NPK) – essential macronutrients we need for plants to grow. Depending on your diet, the NPK contents of your urine will vary – but basically the more protein you eat, the more nitrogen you’re urine will have. Your urine’s NPK ratio could vary from 11:1:2 to 20:1.2:4. In comparison, the garden product ‘Blood n Bone’ has an NPK of 8:1.6:1.5.

Saying all that – some urine still happens when we go to do a poo, but it’s pretty insignificant. However it’s important to be able to drain the worm farm if needed (where everything ends up). To do this we place the wheelie bin tap over a mulch pit which soaks up all urine. A mulch pit can vary in size, but basically it’s just a trench (approx 30cm deep and 50cm long) that’s filled with sawdust or fine carbon that absorbs all urine. Once the sawdust is soaked through (and well before any risk of pooling or run off occurs), you can dig it out into a compost bay or another worm farm to compost fully.

Can you use compost toilets when sick?

If you’re planning on using the finished, composted humanure on your landscape then it’s worth pausing and asking your doctor for advice. When I asked my doctor friend about this he said, generally most antibiotics will not show up in the finished product (composted for 12 months). However he also said that if you’re going through chemotherapy then don’t use a compost toilet as the chemicals can travel through to the finished product. This isn’t medical advice – I’m just sharing a casual chat I had with a friend. You need to ask your local doctor for clear advice to guide you forward. But failing that, the bottom line is, if you’re worried or unsure, you probably shouldn’t use the compost toilet while ill and are on medication.

What happens with the finished product?

“Fecaphobia is alive and well and running rampant. One common misconception is that fecal material, when composted, remains fecal material. It does not. Humanure comes from the earth, and through the miraculous process of composting, is converted back into earth. When the composting process is finished, the end product is compost, not poop, and it is valuable for growing food. Jo Jenkins, Humanure Handbook.

After composting it for 12 months in the worm farm, we’ll then be put the mature compost onto our perennial landscapes. This will include orchard trees, natives and herbaceous shrubs. We don’t put it on our annual vegetable garden, this is a risk management approach as perennials are unlikely to transfer any pathogens that may be present. But as we only use the toilet when we’re healthy, it’s highly unlikely that there will be any harmful pathogens present. IF you’re worried about pathogens you can do a hot composting process as another risk management method.

And just for context, humanure has been used for many thousands of years in agriculture around the world with special mentions to China and the Hunza people of northern Pakistan. The latter who are famous for being some of the healthiest and long-lived people in the world.

Do wheelie bins leach micro plastics?

Our worm farms are in wheelie bins (aka kerbside bins). Someone online sent a comment through saying wheelie bins leach micro plastics. But despite looking into it I couldn’t find anything that speaks to this so I’m not sure where that person sourced their view. Of course, it’s always good to look into things and I will keep asking around, but to the best of my current knowledge I can’t find information that backs up this statement.

Part of me also thinks the when it comes to micro plastics, the train has left the station, the horse has bolted, the can of worms has been opened and it’s unlikely we’ll be able to contain them all again. Does that mean I don’t care about it, that I’ve given up? Absolutely not. If there’s something I can do to to prevent it, I’ll be doing it. But am I going to withdraw from society and live in a remote area where there’s zero risk of coming into contact with pollution in all its forms? No. I’m not. I’m pragmatic that way. And am regularly slammed by online trolls for not being good/pure enough. Sigh.

At the end of the day – the more we can investigate how we as humans can better manage resources in our circle of influence, the better. That’s everything from the reducing our consumption so we don’t have so much stuff all the time to managing the waste/resources we produce like food scraps, paper waste and yes, if appropriate humanure. I look at it like a fun game, the more I can reduce my consumption or cycle waste/resources into a new “thing” the better.

More resources

• For all your humanure curiosity, allow me to point you in the direction of Jo Jenkins and his Humanure books and website here.

• Waterless Toilets – Yourhome.gov.au