Thanks to Joanna Pearsall and Bryan Innes networkers@eartheal.org.nz

Take 3 or 4 200L plastic drums. (Calculate on a litre per person per day for 6 months). Drill about six 5mm holes in the bottom of each.
Use a 10L bucket and draw around on the top of the drum- i.e. using the bottom of the bucket as the template. Cut this circular hole out of the top of the drum and cut the bottom out of the bucket. Fit the bucket into the drum, and construct a pedestal for either sitting or squatting.

Design

Management of the compost toilet.

Seed your toilet with plenty of fat red wrigglers or other compost worms.
The most important thing is to consider the toilet as a worm farm, which you feed daily Worms like:

1. Organic matter – bark, course material will help maintain well drained, aerated conditions - which is very important if you don't want it to be smelly. Use one or two cups full or handful after each time you use the toilet. We sometimes add a little seaweed or grass clippings.
2. Balanced pH: small amount of lime or woodash. (One or two handfuls is enough for the whole drum).
3. Human manure and urine. This is a good diet for red wrigglers and other compost worms.
4. Moisture: Moisture should be that of a damp sponge, add water if it is too dry, or more drain holes if too wet.

The person making a deposit in the drum should throw down a handful of organic matter after each use, and replace the sealing lid. We use a flat piece of aluminium, which we slide across the hole, sideways, so does not get in the way of the toilet seat, which remains up between uses.

Close the lid after use. (Keeps out the flies).

Plant NZ flax, bamboo, bananas or other trees on the drainage bed for the leaky hose. Urine and water from the hand basin is a high value fertilizer and will encourage wonderful growth.

When the drum is nearly full – (depends on how much weight you can manage) move it to the side and replace it with another (seeded with plenty of worms and some compost). Cover the full drum (to keep out the rain and flies) and let it sit while the worms complete their work. This can be aided by the addition of bio-dynamic compost preparations, or some compost from your compost heap, or some forest duff (anything which increases the micro-organisms. Leave the drum covered and resting for about 4 months. By the time you need that drum in the cycle again you should find beautiful soil inside (One reason that it may not be complete could be if a user has been taking antibiotics or worm pills, which can affect the micro-organisms). . If the process is not quite complete, empty the drum where the compost can further mature and adjust the conditions as necessary. Two weeks in a covered heap on the ground is enough to finish the job. Do not leave it too long or the surrounding plants will rob all the nutrients!
Use the compost around trees and shrubs, not root crops. All the pathogens will probably be broken down, but precaution is common sense.

Don'ts

1. Don't put fruit in, it encourages fruit flies.
2. Don't put in more than one cup of well-distributed wood ash (it holds a lot of water and is very alkaline).
3. Same for lime.
4. Don't leave the lid open. It lets in flies and can dehydrate the worm farm.

A healthy compost toilet should be relatively odourless or have a slightly sweet smell. It will not be at all stinky like a long drop. The final compost/wormcaste product will smell earthy and fresh.

Useful variations: Solar chimney for added ventilation

A

B. The roof and ceiling of the toilet Acts as an additional heat collector, Creating increased draught.
Be careful that the worm farm is not too dry. You may need to add water if the ventilation is too efficient.