How to Make a Composting Toilet Free Plans
If you're considering adding a solar composting toilet to your property, but are concerned about the high costs of a manufactured unit, building one is a cost-effective alternative. You can find plans for a variety of designs ranging from the very simple to ones requiring building permits and advanced carpentry skills. For your first attempt at a composting toilet, stick to a simple design. You can always build improvements to your basic composting toilet at a later date. Does this Spark an idea?
Things You'll Need
- 2 foot by 4 foot by 3/4-inch plywood
- Power sander
- Toilet seat
- Pencil
- Jigsaw
- Wood sealant
- 4 pressure treated square posts, each 4 inches by 4 inches, cut to 4 foot lengths.
- 2 boards, 1 inch by 1 inch by 16 inches
- 2 boards, 1 inch by 1 inch by 40 inches
- Wood glue
- Power screwdriver
- 8-inch wood screws
- 1-1/2-inch wood nails
- 2 to 4 plastic storage bins with lids, 50-gallon size
- 5-gallon bucket
- Sawdust
- Scoop
- Pitchfork or shovel
Instructions
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Build the Composting Toilet Structure
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1
Use the power sander to thoroughly sand both sides of the plywood. On one side of the plywood, trace the toilet seat with the pencil. This will be your cut line. Use the jigsaw to cut the toilet seat hole. Sand the edges of the hole.
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2
Follow the manufacturer's instructions to water-seal the plywood. Allow the sealant to dry completely before continuing.
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3
Lay the plywood on a solid, level surface. Position the four 4-inch by 4-inch posts at the corners of the plywood so they are resting vertically on the plywood. Use wood glue to secure them. You should have what looks like an upside down table.
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4
Keeping the table structure upside down, lay down a stripe of wood glue along both long edges of the plywood between the 4-inch posts. Position 1 40-inch board on each strip of wood glue and press to secure. Lay down a stripe of wood glue perpendicular to the 40-inch boards. These wood glue stripes should be positioned 3 inches on either side of the toilet hole. Place one 16-inch board on each wood glue stripe and press to secure. Allow the wood glue to cure overnight. These boards provide stability to the top of the structure.
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5
Turn the structure right side up. Use the power screwdriver to drive an 8-inch wood screw through the plywood into each corner post. Use 1-1/2-inch wood screws to secure the bracing boards to the plywood. Attach the toilet seat to the table structure following the manufacturer's instructions.
Using the Composting Toilet
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6
Set up the composting toilet. Slide one of the 50-gallon plastic bins under the toilet structure. The other bins will be used in rotation. Fill the 5-gallon bucket with sawdust and place it and the scoop under or near the toilet structure.
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7
Keep the toilet bin covered when not in use. To use the toilet, uncover the bin. When you are finished using the toilet, cover the waste with a scoop of sawdust. Be sure to use enough sawdust to soak up any liquid waste and to completely cover the waste with a 1/2-inch layer of sawdust. This will keep the compost moist but not wet, and will diminish odors. Cover the bin with the lid.
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8
Every few days, use the pitchfork or shovel to mix and aerate the waste in the toilet bin.
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9
When the bin is 3/4 full, replace it with an empty one. Take the full bin to a location that gets full sun. Thoroughly mix the partially decomposed waste and add a thick layer of vegetative waste--sticks, leaves or lawn clippings.
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10
Every two weeks, turn the compost in the bin to aerate it and encourage decomposition. Proper aeration will minimize odors while the sun will heat the compost and speed the composting process. Your compost will be ready to use within 6 to 12 months, depending on the amount of heat and aeration it receives. It will look like dark, rich potting soil when it's ready.
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Tips & Warnings
You can also add waste from your solar composting toilet to a compost heap or a barrel composter. The key is to make sure you compost in a sunny location to fully utilize the solar heating power to aid decomposition.
Do not use human waste compost on root vegetables that will come in direct contact with the compost. While human waste compost is generally safe, there is a small chance of ringworm eggs surviving the composting process. As long as the compost does not come in direct contact with food, there is no danger of spreading disease. If you know that no one who uses the solar composting toilet is infected with ringworm, there is no danger of food contamination.
