Development of an accessible analytical model for small-volume feces composting

ABSTRACT Developing small-volume composting systems can help improve sustainable sanitation and waste management at a household scale in constrained environments. In this work, an accessible analytical model that describes the container-based composting process is presented. The model focuses on the compost temperature as the main process parameter and was validated with an initial experiment and then used as a simulation tool for scaling a compost reactor with a mixture of feces and sawdust commonly found in dry toilets. Following literature thresholds for pathogen inactivation, the compost in the second experiment surpassed the required temperatures of 55 °C for more than 3 days. This work demonstrates that pathogen-inactivation temperatures can be achieved for a self-heating, container-based compost system at a household scale with a minimal experimental setup. Furthermore, the process can be described with an accessible analytical model that ensures ease of replication even in constrained environments.