How to Make Humanure: Recycling Human Waste
This article has been contributed by Anne Marie Duhon. Anne Marie is a wife, mother of six and a full time off-gridder. She and her husband currently live in a totally off grid 200 sq foot “tiny home” and are in search of (again) that elusive perfect spot to call home. Besides being a wife and mother she, and her family, have raised many different animals on their various homesteads and have lived and loved being off the grid and many miles from the nearest paved road. She would like to share her first hand experiences and help others to learn to live and love living off grid and being as self reliant as possible.
What is humanure?
Humanure is our urine and feces in a nutshell.
We see it as waste Nature sees it as a good by-product of human existence. Our manure contains many nutrients that enhance plant growth. Human excrement could be a major source of soil fertility if properly recycled. When discarded into the environment as a waste material (“human waste”), it creates pollution and threatens public health. When recycled by composting, the pollution and health threats can be eliminated.
It is well known that humanure contains the potential to harbor disease-causing microorganisms or pathogens. This potential is directly related to the health of the population which is producing the excrement. If a family is composting its own humanure, for example, and it is a healthy family, the danger in the production and use of the compost will be very low. If one is composting the humanure from orphanages in Haiti where intestinal parasites are wide spread, then extra precautions must be taken to ensure maximum pathogen death.
Compost temperatures must rise significantly above the temperature of the human body (98.6F) in order to begin eliminating disease-causing organisms, as human pathogens thrive at temperatures similar to that of their hosts. On the other hand, most pathogens only have a limited viability outside the human body, and given enough time, will die even in low-temperature compost.
How Can Humanure Be Recycled?
Humanure can be recycled in two basic ways. First, it can be applied raw to agricultural land. But this method can cause pollution and spread disease if the same plot of land is used over and over again. The second way is by composting. This is the process described in this article and the method my family has been using for years.
Compost microorganisms will digest and convert humanure into a safe and pleasant soil-like material when the humanure is combined with carbon-rich organic materials such as grass, leaves, sawdust, hay, sugar cane bagasse, rice hulls, straw, and other animal manures.
A compost pile allows us to combine various organic materials above ground, thereby providing oxygen to the aerobic microorganisms inside the pile. It also allows us to keep the organic materials quarantined inside an enclosed area away from people, dogs, goats, chickens and other creatures that should not be disturbing the pile.
How to Make a Composting Systems On The Cheap
There are three componets to a humanure composting system. They are 1/ The toilet 2) the compost bin and 3) the organic material containers.
The toilet is basically a 5 gal bucket hidden in a box with a toilet seat on top. The toilet is used only to hold “deposits” covered in organic material (more on that in a minute) until someone takes the toilet to the compost bin and dumps it. Here is how to make a toilet box (feel free to just use this as a rough idea and tweak it to fit whatever materials you have laying around):
A hinged humanure toilet box will be 18″ wide and 21″ long. You’ll need:
- two boards 3/4″X10″X18″
- two 3/4″X10″X19.5″
- two hinges
- one piece of 3/4″X18″X18″ plywood
- one piece of 3/4″X3″X18″ plywood
- standard toilet seat
Hinge the two pieces of plywood together. Cut a hole in the larger piece of plywood to fit the top of the 5 gallon toilet receptacle. Make sure the hole is only 1.5″ back from the front edge of the plywood. Always use identical receptacles in a humanure toilet so they will all fit correctly.
Screw boards together making a box 18” x 21” x10”. Screw 3” x 18” board to top of box. Leave the 18”x 18” plywood top loose on the hinges.
When screwing the legs to the inside of the box, make sure the top edge of the box will sit about 1/2″ below the top edge of the toilet bucket (the top of the toilet bucket rim will stick up through the box by about 1/2″). Screw down the toilet seat to the top of the box over the hole. Voilà a toilet!
How to Build a Compost Bin
A simple compost bin is four pallets set on edge and tied together in a square. More permanent bins involve posts and boards.
If the top of the compost is accessible to chickens, dogs, etc., it can be covered with wire mesh to prevent the compost from being disturbed. A square piece of loose wire fence works well and is easily removed when adding compost to the pile.
The compost bin itself can be built from pallets, scrap wood, wire mesh, stacked bales of hay or straw, other recycled materials, or even masonry materials such as block, brick or stone. Do not use lumber that is treated with chemicals.
Organic materials or Cover
Without proper cover materials in large enough quantities, the humanure compost toilet will not work.
A family can usually find cover materials by locating local sawmills or sawdust sources, purchasing peat moss in compressed bags, buying hay or straw from a farm or farm supply store, scavenging materials from the local environment such as leaves, grasses and weeds, or getting leaves from the city after they’ve been raked up in the fall.
Some cities sweep up leaves then dump them into piles where they’re left to rot. Rotted leaves are ideal for humanure toilets. Contact your city to see if such a source of organic material is available to you. Or you could drive around during the fall and ask people if you could have (or offer to rake up) their leaves.
Avoid wood chips or wood shavings as the larger particles do not compost well. Cover materials should not be wet. They should have basic carbon content from stems and leaves and other plant cellulose byproducts. Again, the simple rule when using cover material is if the compost that is covered smells unpleasant, it needs more cover material. Cover until there is no bad odor.
How to Use Your Humanure Composting System
Once you have all the parts put together and where they belong, using your system is no harder than using a flush toilet and is a lot less wasteful of water! Here’s the process…
Make a deposit. Thoroughly cover all deposits with clean cover material. You should have on hand near the toilet a container full of cover materials at all times. Add all urine, fecal material and toilet paper into toilet. If the toilet is full, lift plywood lid, remove toilet, put on plastic lid, and set the toilet aside to be taken to the compost bin. Insert empty bucket into toilet box. Make sure empty toilet bucket has 2-3 inches of clean cover material in bottom before use.
COMPOST THE HUMANURE
Empty the toilet contents into a compost bin constructed for this purpose. Never discard the toilet contents into the environment.
Erect the compost bin on a soil base dished out like a shallow bowl, starting the bottom of the bin with an 18”-24” thick, dense layer of organic material such as hay, straw and/or weeds.
Dig a depression into the top center of the bin contents and deposit the toilet materials into the depression when emptying a container, then always cover new deposits with clean cover material. Collect the toilet material in an active bin for at least a year, and then allow the material to age in that bin, now passive, for another year while the next active bin is filling. In any case, allow the compost bin contents to age for approximately one year after collection before applying to soil.
If the temperature of the compost is monitored and consistent thermophilic (hot) conditions are observed, the finished compost may be used for food production. If in doubt, use the finished compost for horticultural purposes. Wash the toilet containers before returning them to the toilet room and deposit the wash water into the active compost bin. Add all food scraps and other organic materials to the active bin. A good mix of organic materials makes for better finished compost.
And there you have it!
An easy way to take care of human excrement that is safe, effective and environmentally friendly!
A low-cost composting toilet system can be very useful as a back-up toilet in an emergency situation when electrical or water services are disrupted, or when the water supply is diminished as during a drought, when flushing drinking water down toilets becomes especially ridiculous.
It can also be very useful in any area where water or electricity is scarce or non-existent.
Finally, a simple, low-cost composting toilet system is attractive to anyone seeking a low-impact lifestyle, and who is willing to make the minimal effort to compost their organic residues
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