How to Compost Human Waste
Composted Human Waste is excellent fertilizer for non-edible plants.
Disclaimer: These are my suggestions only, based on recommendations from the World Health Organization. I make no guarantees about the accuracy of this information, and whether or not it applies to your specific situation. If in doubt you should check with your local authorities.
This is an article on how to safely and easily compost human waste. It’s not difficult, but you MUST do it right, or people could get sick. The main issue is the solid waste – feces. It’s easy to deal with urine. More on urine below.
Solid human waste (feces) can be safely composted by carefully following a few simple guidelines.
First, it is much easier to compost human waste waste from a urine diverting composting toilet. The material removed from a urine diverting toilet should be just slightly damp – perfect for composting. With a non-urine diverting toilet, the contents will be too wet for efficient composting, and the combination of urine and feces creates an anaerobic environment that allows very stinky bacteria to flourish (think outhouse or portable toilet at large public event. Ugh!). A urine diverting toilet is key to the successful composting of human waste, in my opinion.
Composted Human Waste
When the human waste is removed from the toilet, you should place it in a dedicated composter. The type of container is very, very important! It must not leach out the bottom or sides, as this might contaminate groundwater. It must be protected from rain and snow – it cannot get wet. And it must have lots of ventilation.
Aerobin hot compost bin for human waste
Hot composting is a game changer.
Recently I have become a firm believer in “hot composting”. Rather than wait a year or longer for waste to compost in a typical compost bin, you can drastically speed up the process with hot composting – which is basically an insulated compost bin. I am now getting compost in about 8 weeks – sometimes even less. All visual traces of human waste and toilet paper are disappearing very quickly – often in just a few days. (This is in summer. In the winter it will be slower).
Many hot composters are pretty expensive, but I use the 55 gallon Aerobin from Costco, which is very affordable. It was a bit of work to assemble, but it is working great, and I recommend it. The 55 gallon bin is perfect for two or three people, full time. Bigger groups might consider the 111 gallon version. The Aerobin is not quite as sturdy or as well insulated as the more expensive bins, but at 1/3 of the price you can’t beat it.
You can also make a hot composting bin. Instructions are here.
Redmon Compost Tumbler
You must add other material to the compost bin, such as sawdust, leaves, grass, table scraps etc. It is a good idea to learn a bit about composting basics online. You need about a mix of “greens” and “browns”.
I just toss in some kitchen scraps (nitrogen rich) and sawdust or shavings (carbon rich) about once a week, and mix it all up with a small gardening fork (This aerates the material and helps it break down). I add human waste as we produce it – about once a month. Dig a little hole for the human waste inside the bin, and dump it (preferably without the compostable bag which can take a long time to break down), and cover with sawdust and kitchen scraps.
Emptying the toilet is NOT gross!
Much has been written about the “correct” ratio, and no one seems to agree. I don’t think about it too much, and add roughly 50:50 greens to browns. Human waste can be considered neutral, and not a green or a brown.
Feed the beast!
If possible you should “feed” your compost bin with something once or twice a week. This keeps things going, and speeds up the composting process. At a minimum, you should definitely monitor the contents from time to time. If it seems wet (it should be just slightly damp), add dry grass, dry leaves, or some other dry carbon rich material. If it’s too dry, you’ll need to add a bit of water, and possibly more nitrogen rich material like green plants. It’s actually pretty simple and easy. Keeping the contents just slightly damp will ensure rapid and complete composting.
The beauty of the hot composting method is that you will be removing finished compost from the bottom of your container as fast as you can feed it in through the top. After the material is removed, some suggest storing it in a pile for several more months, to ensure it is fully broken down and safe for non-edible plants as fertilizer.
Compost Tumbler with large opening hatch
Additional Tips to Successfully Compost Human Waste
You might eventually need two compost bins to compost human waste, especially if you have a bigger family. In this case, use one at a time. When the first bin is full, start using the second bin. When the second bin is full, the first one should be ready for the plants.
There are bins with two chambers. This is intriguing, but I have not tested them. I don’t know if the capacity of each side would be sufficient.
Adding lime to the compost after it has been removed from the bin will drastically reduce the time it has to sit, before being safe to bury or spread on non-edible plants. Use roughly 3% lime to total compost volume.
Note: Lime may reduce the quality of the compost, depending on how you plan to use it.
You must never put composted human waste on edible plants, because of the small chance that dangerous bacteria are still present. Always use human waste compost on non-edible plants only, or bury it.
Pee is Easy!
It is extremely easy to deal with urine from a urine diverting toilet. You can often just drain it into a French drain, or use it as fertilizer. Some people dilute urine prior to using as fertilizer, others do not find dilution necessary.
You can download a wonderful guide to using urine as fertilizer from the Rich Earth Institute here. They have worked with numerous universities, public health regulators, the WHO and even the EPA to establish principles for using urine from a urine diverting toilet as fertilizer. The take away message from this guide is that, at the household level, urine is not a health risk, and can be used directly on plants without treatment. Sadly, many (most?) local governments are unaware of the facts around urine, and think it is somehow dangerous. Not true. Send them the guidelines.
If you follow these simple steps, you will have a complete, safe, odor free and low cost waste treatment facility on your property. Unlike conventional sewage or septic systems, you will completing the circle of nutrients, returning much of what you consumed back to the earth. You won’t be creating toxic sludge to be burned in a high temperature furnace, or treated in a typical sewage treatment plant using vast amounts of energy and producing considerable CO2.
Your well measured input on the proper, safe use of human manure is highly appreciated. I am a 51 year old South African who grew up surrounded by multitudes of subsistence vegetable farmers who never thought twice about the value of using human manure in growing their edible cash crops and we never heard about any resultant health risk of such usage. What has really changed from my daily witnessed life experience of human waste usage? My somewhat stronger personal feelings are, once human manure is adequately treated, it should be safer to be used on edible crops as well.
Human waste has the potential to be extremely dangerous. “Adequate treatment” is tricky to achieve. A small amount of E coli can cause severe illness, blindness or death. Careful studies have shown that very small amounts E coli (and other pathogens) may occasionally be present in human waste even after 1 year of composting. You can’t know if your compost is safe, without sophisticated testing. It’s not worth the risk. The WHO and other health organizations state that we should therefore not use human waste on food crops. In Haiti, human waste is very carefully composted in a large scale commercial facility, and the temperature reaches 55 degrees C for a week or more. This kills everything. Then the waste is tested repeatedly, and only after it is determined to be pathogen free, it is used on crops. So yes, it’s possible. But generally it’s not practical. I strongly recommend never using human waste on edible crops.
Hi Richard
Have you been involved in the making and testing of humanure?
Can you support your strong opinion about the dangers of human waste in a composting process with relevant research – that contradicts the research done by SOIL in Haiti and x-runner in Peru?
Please let me know – as we can provide information to the contrary.
Regards
In Haiti it works because highly qualified, well trained people are monitoring the pathogen content of the waste with sophisticated lab testing. They know that the temperature of each compost pile has to reach a sustained, very high temperature, and they closely monitor the temperature of all areas of the pile. This is relatively easy to reach in a tropical climate, and hard to reach in most part of North America. Most people do not have the knowledge, training, skill or expertise to do this safely. So it’s not safe to do. This is why the World Health Organization recommends using compost made from human waste on non edible plants. The humanure approach relies on a very long waiting period, to ensure there are no dangerous pathogens. But small amounts of E Coli have been found in human waste stored for long periods, even a year or longer. Recently a child in California went permanently blind from eating food contaminated with E Coli. That’s a human being that will live their life in darkness because of someone’s relaxed attitude around human (and animal) waste. Putting human waste on edible plants, unless you have the equipment, training, lab facilities, skill and motivation to do it properly, is a bad idea.
Richard, I purchased a Villa toilet from you about 5 years ago. In the composting discussion and questions, there is nothing about the green bags and how long they take to decompose. I have been putting the bags in my regular compost and they are still visible a year later. I’m wondering about the incinerator advertised on the Separett website, or if there are any other incinerator products you might recommend.
Jan
Incinerators are a bad idea. They use an enormous amount of power, and have incredibly expensive parts that fail regularly. They are the absolute worst solution in my view.
If the bags have not composted, then you are not composting successfully. They break down quite easily. Usually too easily. I suspect your compost is too dry. Please see my page on how to compost human waste, and possibly read more on numerous websites about composting in general.
Also, small fragments of bags are not a problem. Remember never to use compost made from human waste on edible plants.
What is the difference between composting human and animal waste? Are there any other materials needed to compost human waste? Can Urine Diverting Toilets be keep in a home?
Thank you!
Human waste is much more dangerous than animal waste. No comparison. You can use manure from livestock on edible plants. You never use human manure on plants. The toilets are designed to be inside a home. Human manure vs animal manure
I’ve been interested in humanure since I’ve learned about it from YouTube years ago. However, they used it for fruits and vegetables as well. There has to be a way to confirm if the pathogens have died so I can use it for fruits and vegetables plants. I don’t want to bury perfectly good usable compost if I don’t have to. I would like as much information as possible because I would like to develop it for larger scale planting…
Thanks in advance!
Jennifer
The compost can be taken to a lab, but it is expensive and hence impractical. It is done in Haiti and Africa but under strictly controlled and monitored conditions where the compost has to reach and maintain very high temperatures. Don’t under estimate the danger here. E coli can kill people. Use it on ornamental plants only after a lengthy period of composting and it is safe. Using humanure on vegetables is gambling with people’s lives, and against all WHO guidelines.
Where can I find out more about the compost tumbler shown on this page…can’t seem to find it anywhere online.
thank you.
d
I don’t know. These are just random pictures from the internet. Compost tumblers are easy to find.
Do you need to dilute the urine before watering onto plant beds?
Some people do not, but my concern would be odor.
What if you used cat litter?
In the Nature’s Head? It would not work.
What happens if there is urine mixed with the human waste., how do you separate the urine from the feces before composting..
Secondly., how is the safest way to apply human waste compost to crop fields such as corn and pepper farms..?
The urine is separated in the bowl, by the toilet. If urine and solid waste is combined, it will smell much worse. You cannot apply human waste compost to food crops, because of the small risk that the material you are using is not fully composted. Use on non-edible plants only.
How long does it take to compost human waste?
It depends on the temperature outside. Anywhere from 2 months to a year.