The social aspects of designing an anaerobic microdigester with combined thermoelectric heat and power generation to convert human excreta to electr...

More than 894 million people do not have access to clean water sources and as a result, 1.6 million children die each year from diseases caused by fecal-­‐oral contamination. Due to poor sanitation practices worldwide roughly two billion people use non-­‐sewered or non-­‐ piped sanitation systems that often pollute the water supplies. The solution to this problem is two-­‐fold. The first and most important part is the social aspect of the problem. This includes establishing an adoption plan for the technology in the target community to ensure it is used as intended and not abandoned or scavenged for parts or other uses. Adoption also includes affordability and practicality of the design (local manufacture), and spreading knowledge of how to improve existing sanitary practices. The second part
of the solution is the actual technical design of the unit to fit the community where it is to be implemented. To better understand the social and economic aspects of a proposed unit, we interviewed rural and urban individuals in Faisalabad, Pakistan. The results of this survey were used as the basis for a modified engineering design we are currently testing. As a result of the information that was gained from the survey, a very simple engineering design of the unit was created that can be built with limited technology and is practical for the Asian subcontinent. The design is of a single modular unit that will be able to produce heat, electricity, fertilizer, and methane from human excreta. The unit is small in size so that it may fit in any location within a house to enable familial adoption,
and it is also simple in design so that it only requires basic maintenance for proper use. Currently there are other more complicated systems that convert human
excreta to methane gas, however this unit is unique in the sense that it can be used at the household level both safely and affordably. It is evident that the social aspects of this project, not the technical, dictate the majority of the engineering design constraints of the unit. Finally, once the unit is implemented on site, social work needs to be established to ensure the proper use of the unit and also to determine how well the engineered unit is doing on site. [authors abstract]