Just a thought, on greening deserts, would it be possible to use human manure to add organics to the soil. I realize that there need be a way to make the waste safe (free of pathogens), but there are some positive results in turning around poor soil using human manure. If there are no issues, like in the U.S., where municipalities, most of the time are not sure what might be in there solids. In under developed areas you pretty much only have animal and human waste to consider. Of course there may be social or religious consideratons to take into accout. (I hope this is the correct place to pose this question, please forgive me, if it is not).
Wonder if owen knows what they are doing with there feces and urine now?
like Gerald said making the human manure safe to use is a must, but one can reduce the probability of pathogens and disease by not using human manure on food crops but crops for biomass.
the biomass crops could then be used to mulch food crops.
Also i bet a lot of people in the sahara have never composted, so education in proper handling and compostingshould be a high priority.