Return to sender

Return To Sender

It seemed obvious to me that I needed to go far further with utilising humanure than I had previously (we always had a composting toilet, but it was emptied into the orchard) – after all most of the minerals we eat go straight through us, except if we are actively growing (i.e. children).

It is the interactions between the minerals in our bodies, i.e. the energy transactions that happen in our bodies, that we run on, just as plants run on the energy transactions and don’t actually take the minerals out of the system… they are just recycled. If we then dump these minerals, call them waste, and put them somewhere else, out of our own backyards and into somebody elses’s, we are constantly removing key minerals from the immediate environment we are growing our food in, which means we have to bring more in to grow food. Many ancient civilisations used humanure, and believed it was essential to recycle humanure to maintain a sustainable system.

We have had many expensive and not so expensive composting toilet systems over the years, and there were always things I did not like about them. The most common was that none of them were easy for me to manage myself, none of them made good compost as far as I was concerned, and many were not practical or user friendly at all.

Recently we discovered the ‘Loveable Loos’ website run by JC Jenkins, the author of The Humanure Handbook (a great book on recycling humanure), and we built a ‘loveable loo’ despite the dreadful name! We love these clean, non-smelly, easy to empty toilets (we had a bucket of sawdust in the toilet, so each time we used the toilet we threw in some sawdust into the bucket). However, that’s the easy part – we then had to face the ‘composting’ aspect of it, which I admit I have been avoiding for many many years!!

We bought a compost thermometer and discovered it was easy to get the right temperature – so long as you add a carbon source like hay or straw to build a non-smelly, aerobic, perfectly acceptable and even beautiful, compost heap with the humanure, you can get it to the required temperature in a matter of days. These compost heaps just get added to each time the bucket is full, and you will find that if you make the heap well the temperature keeps above the critical level while you are adding a bucket once or twice a week. I felt I could cope with this system, no smell, lovely looking compost heaps, easy to achieve the temperature that keeps thing safe…

Then we discovered another entire level that we could take humanure composting to. Ecology Action (of BioIntensive fame) have been researching for almost 40 years around how to grow food sustainably, and they believe, as did many cultures before us, that ”true sustainability is only possible in the garden when our humanure is returned to the soil it came from.”

They have published a booklet called Future Fertility by John Beeby, a micro-biologist who was an apprentice at Ecology Action for some years. The entire 164 pages are about how to return our urine and humanure back to the land that grows our veges in a way that:

–  is safe and legal,

–  produces sufficient humus to be growing soil (rather than depleting it),

–  returns minerals,

–  applies nitrogen properly.

Ecology Action even acknowledge and discuss the fact that if we are not growing and eating nutrient dense food, we will be recycling the deficiencies, so we may need to bring in minerals for a while.

“If the soil is deficient in some mineral, the food produced by that soil will be deficient in that mineral. If we eat only crops produced by that soil, we too will be deficient in that mineral, as will be our waste. When we add our waste to the soil that feeds us, or cured compost generated from plants the soil grew, neither the waste nor the cured compost generated from the crops the soil grew can be only fertilisers used to maintain the soil at a maximum level of health. In order to balance the soil minerals, have the soil analysed by a reputable laboratory that can advise you on the type and s quantity of organic fertilisers to add to the soil” (Future Fertility, John Beeby, page 18).

I was totally inspired and galvanised by that booklet, and have gone on to develop my own system using the knowledge I’ve gleaned so far. I hadn’t realised that my ‘loveable loo’ system was probably losing a lot of its potential minerals, especially the nitrogen, because I did not understand just how volatile they could be.

We have a toilet (currently serving 3-4 families in house trucks etc.) with a wooden seat and a 20 litre bucket to catch both urine and humanure, adding a 50/50 mix of sawdust/soil each time we use the toilet in such a way that the sawdust and soil are able to absorb the urine. If that doesn’t happen, you lose the nitrogen very quickly, which means you will have to pay (or work harder) to have healthy soil… and this is all about efficiency for Ecology Action!

As each bucket is filled, it goes to the compost heap beside the housetruck which is right over the fence from where we feed out hay, minerals, seaweed, and stock primer to our cows each morning.

Before feeding the cows (6 Dexter cows and calves)) each day, I rake up what was not eaten or trodden into the ground the previous day, and throw it over the fence beside the current compost heap.

I follow John Beeby’s instructions for making it safe to use compost with humanure/urine in the garden. In order to kill potential pathogens in humanure, we must heat the compost heap to at least 55°C for at least 21 consecutive days, or 60-70°C for 3 consecutive days before adding to the garden. These temperatures can generally be reached in the centre of a properly maintained aerobic compost pile that is 1.2 x 1.2m and 1.2m high or higher. However, the outer layer of any compost pile is usually cooler, so if humanure is added to a compost pile, any pathogen contained in the manure must eventually be turned into the centre of the pile to be sufficiently heated and killed.

Each of my heaps is circular, and I make them BioIntensively with a high carbon:nitrogen ratio of at least 30:1. I prefer up to 60:1, however I have to keep an eye on the temperature to ensure safety levels are reached. If the compost heap is too hot (it is relatively easy to keep it at 55°C for over 21 days the way I make my heaps), then we risk losing our valuable carbon, minerals and microbes. If it is cold, we risk not killing the microbes we need to kill to keep the compost safe to use in the garden. A compost thermometer is essential.

So I begin a compost heap by forking up the ground underneath, lay down a 12cm layer of carbonaceous material to keep the air and drainage working, (this must be an aerobic heap), and spread 2cm of soil over this carbon to soak up any urine or moisture that is not held by the sawdust and soil in the bucket. Then I empty one toilet bucket over the carbon in a thin layer, and sprinkle that with a little more soil to hold any volatile nitrogen. After that, I sprinkle a handful of compost minerals and microbes, to ensure we are not just recycling the deficiencies (we have begun here with a Brix of 1 for the pasture and garden plants), and sprinkle on that any woodashes and Biochar from under our outdoor bath (there is nearly always a little biochar after each bath), seaweed we have collected from the beach, agnihotra ash from my fires, chicken manure from the chicken house, and any bone or shell ash which we make with all bones left over from broths etc. in the kitchen. Then I just keep going with the layers, another layer of hay etc etc.

Once the heap is finished and the temperature has dropped from around 63°C, I turn these humanure heaps (unlike my other BioIntensive heaps) to ensure any harmful microbes that may have escaped the heat on the very outside are now in the middle of the turned heap.

Part of the amazing research done at Ecology Action shows that if you are growing food for one person BioIntensively following their strategies and techniques, you will be growing just the right amount of carbon and have just the right amount of soil (which you take from the first trench in each bed each time you prepare that bed for planting) to compost the humanure from one person! So it’s no great drama to find the carbon, or no great cost.

All of our kitchen scraps go into the worn farms, which are producing highly mineralised, microbially rich vermicast (because we also add Compost Minerals and Microbes to the worm farm), and they are also producing an abundance of high brix live protein to feed the chickens.

All of the bones we have left over after we make bone broth etc. go into a barrel beside the worm farm which has a screw on lid so we can’t smell the contents. When the barrel is full we make a fire and burn the bones to get bone and shell ash, which we then store in a dry container and sprinkle in layers on our compost heaps to add the much needed available calcium. Putting the calcium into the compost heap in this way will ensure it is held by the carbon (humus or biochar), and it will remain in the soil until the plant roots need it rather than washing away with the first rain like lime does.

The only other waste we have in our kitchen is whey, which we use to soak our chicken grains in before sprouting them.

I’m designing a system that works for me. I enjoy every part of it, I can do every part of it myself, and once I have the Brix of my plants up to over 14, I think I will be able to manage the system without having to add any bought in products. That is my goal. At the rate things are going here now, I think I can achieve that in 1 year, if not then definitely in 2 years.

We are aware that the only legal methods of disposal of compost toilet compost appears to be removal by a septic tank operator, or in some cases burial within a deep trench, outside of areas used for gardening. Over the next few months we will work through the design of a standard method which ensures safe handling, a safe product, and still retains maximum nutrients. Bob will be presenting this to our local council for their approval. If we can achieve this we will produce a booklet detailing the whole protocol. Theoretically, if it passes our council, it should pass others,  but they do have their own peculiarities, so if you want to be legally sanctioned, you will need to apply to your own Council.  Keep an eye out for our booklet ‘Return to Sender: Composting Humanure Safely for Full Recycling of Nutrients’, which will be published soon.

Kay Baxter