Final report from the week-long “Six Ways To Die” workshop.
This team presented an integrated system of two ideas.
The first idea was to take the standard pit latrine which is used by many NGOs in disaster relief and to line the pit with a biodegradable plastic bag good for 15 people for six months. At the end of this period, the bag would be sealed and left to anaerobically compost. The bag is designed to degrade slowly enough (at least one year) that the human waste is no longer dangerous when the bag rots. This system has many of the benefits of a sceptic tank system and a composting toilet system combined, in terms of sanitation and ease of handling, and has a lot of potential. http://www.jordklok.se/ is one vendor of biodegradable bags of this size.
The other idea was to build a toilet block (say 10 units) into a standard sea container for easy shipping. This toilet block would feature a biogas digister and produce energy. An initial calculation using an online biomass energy estimator suggested that about 10 cubic meters of gas a day would be produced by 200 persons, or about half of what would be needed to cook all meals. However, if the toilet system shipped with pressure cookers and gas stoves with sleeves, the biodigester toilet might produce all the necessary energy for cooking for the community served.
The system was imagined as a replacement for temporary sanitiation solutions for long-stay encampments. Cost was estimated at 20,000 EUR per 200 persons, or 100 EUR per head. However, it should be remembered that this is a permanent sanitation solution (it could easily last 20 years) and also provides cooking fuel – not bad for 5 EUR per person per year of sanitation and cooking fuel service.