I like to urge caution I ...

I like to urge caution

I would urge you to approach this challenge very cautiously. Over the years a range of low cost toilets have been designed for use in developing countries. It might be good idea to first do an exhaustive literature (internet) search to see what designs are available - what has been proposed - what works - and more importantly what does not work.

There is a NGO in Semarang, Indonesia providing toilets that cost about $10 each (I think - but could be mistaken - but it is at an exceptionally low cost). This is just an example, but it confirms what I said above. The Bill and Melinda Gates Foundation has been providing funding in the past, for innovative toilet designs.

A properly functioning toilet is not solely a technical challenge to be solved. A range of environmetal, social and cultural factors also come into play. What is acceptable in one country may not necessarily be acceptable in another country. For example, a toilet providing the raw material for a biogas generator may be acceptable with some and totally unacceptable in another society simply because the biogas is being generated by sewage. Similarly treated sewage or sludge may be considered by some as good and cheap fertiliser, but not by others. Essentially, a universal design may not necessarily work in every society and culture and region and country.

You may want to contact Engineers Without Borders. They have chapters in a lot of developed countries. They are very active in developing countries working on projects in the areas of water supply, sanitation and similar. They also liaise with various universities looking for solutions. You may wnat to discuss your concept with them.

Please don't misunderstand me here. I am not discouraging your in your endeavour, but rather urging caution and emphasising the need to do exhaustive research and investigations.

Hope my comments are of some value.

All the best in your endeavour.