Engaging Students in Waste-to-Energy Research Using Model Biodigesters

Anaerobic digestion (AD) is a natural process whereby microorganisms break down organic material in the absence of ­oxygen. Biodigesters (sealed tanks where AD occurs) are complex ecological systems where different microorganisms work together to produce biogas (a mixture of methane and carbon dioxide). They are used to produce energy and fertilizers from organic wastes, such as food waste, crop residues, and animal manure. This article describes the use of simple model ­biodigesters, built from low-cost or repurposed materials, as a way to introduce students to physical and conceptual models while learning about resource recovery, waste management and sustainability. This article provides an overview of how teachers can implement this in their science classrooms to engage students in science and engineering practices (SEPs). When used in schools in Ghana and the US, students learned about AD, developed research questions, and built a model biodigester as a tool for scientific inquiry. They collected and analyzed data (e.g., daily biogas and methane production), and they interpreted their results to answer their research questions and make recommendations for local ­biodigester construction. More complete information about engaging students in authentic science using biodigesters is available on our website.