Solar Compartment Design Methods, Performance Analysis and Thermal Data for Solar Composting Latrines: A Full Scale Experimental Study

Abstract

Developing nations require improved sanitation technology implementations to reach Millennium Development Goal 7-C. Unfortunately, to date, the goal does not look attainable by the 2015 deadline - 2.5 billion lake access to improved sanitation. Pathogen resistance to disinfection or inactivation in latrines is multifaceted. The full-scale solar composting compartment studies at the University of Kansas have advanced the knowledge about feces composting in solar compartments based on climate and materials. The thrust of the studies has been to record temperatures within simulated compost and compost - thermal disinfection can be reached with various designs. Four design types were proposed as having a significant beneficial effect on temperature profile in the compost. Two design methodologies are recommended for thermal disinfection: capturing heat from the sun or protecting compost heat from escaping the compost. Both designs require moisture loss to be reduced with an evaporation cover (e.g. sheet of plastic). Under desiccating conditions decomposition is slowed dramatically, which results in little to no heat production from the composting process. Insulating moist compost with slab insulation (e.g. rigid polystyrene) will increase temperatures in the compost. Insulating all six sides of a compartment will yield appropriate composting conditions for extended periods. Extensive thermal data for simulated and actual compost has been placed in a supplemental appendix. For access to the supplemental appendix, please contact the author at joeren115@gmail.com. Further studies are required to determine effects of compost age and oxygen on compost pile temperatures for solar composting compartments.