Incinerating toilets are self-contained units typically consisting of a traditional commode-style seat connected to a holding tank plus a gas-fired or electric heating system to incinerate waste products deposited in the holding tank. Such systems do not require water to operate. When properly maintained and functioning, they produce a fine, sterile ash that can easily be disposed of with other trash. Unfortunately, because the incineration process also destroys nutrients, the ash cannot be used for fertilizer.
Incinerating toilets are relatively odorless compared to typical portable toilets. They can also be used in unheated buildings, although if using propane, the U.S. EPA recommends that the propane tank is sheltered from severe winter conditions. Some incinerating toilets need to be operated after every use and may not be used while incineration occurs. Also, the operating costs for these products vary widely, as they are dependent mostly on the electric or propane costs in your region.
If you are considering using an incinerating toilet, check with your local public health authority to find out the requirements governing installation and use. Some authorities may require certification in accordance with NSF Protocol P157: Health and Sanitation of Electrical Incinerating Toilets.