Thousands of schools around the world use worm bins to teach students about recycling organic wastes and to involve them in investigations of worm biology and behavior.  Vermicomposting (from the Latin vermis, for worm) is used in large-scale industrial applications, with waste streams including sewage sludge, animal manure, and food wastes.  Unlike themophilic composting, vermicomposting does not get hot.  In fact, temperatures above 35°C would kill the worms.  In all types of composting, microorganisms play a key role in decomposition.  In vermicomposting, worms help by physically breaking down the organic matter and chemically altering it through digestion.  The end product, vermicompost, contains plant-available nutrients and compounds that enhance plant growth. 

An earthworm is much like a small version of a cow, horse, or any animal with a rumen.  Worms ingest sand, dead plant material, bacteria, and many other microparticles, as food.  Inside the gut of the worm, conditions are perfect (good moisture, well aerated) for bacteria and fungi to speed up their growth processes and decompose more of the organic matter.  The worm mixes all these things in their gut increasing bacterial growth considerably.  After the worm uses the nutrients it needs it excretes in the form of castings, organically rich material suitable for soil enrichment and plant growth.