Anaerobic Digester: C:N Blend Lab

Anaerobic digestion converts organic feedstock into biogas inside a sealed, oxygen-free tank, using microbial communities whose growth depends heavily on the feedstock's carbon-to-nitrogen (C:N) ratio. Too much carbon relative to nitrogen starves the microbes of the building blocks they need to grow; too much nitrogen relative to carbon drives ammonia to toxic levels. This lab lets you blend straw, cattle manure and food waste — each with its own natural C:N ratio — and watch the resulting mixture's ratio and biogas yield tracked live on a peaked yield curve, alongside a 3D digester tank whose bubbling and microbial population respond to whichever regime the blend falls into.