Vermiculture, growing worms, can be done on any scale: in a bin in the corner of a domestic kitchen or balcony to dispose of left-over food; or in a large municipal plant to convert waste into a financially valuable compost product.
The amount of soil worked over by earthworms is tremendous: 4-36 tons of soil passes through the alimentary tracts of the total earthworm population living on an acre in a year, soil cellulose-decomposing bacteria take apart 100 billion tons of plant tissue that die every year; a biomass more than 10 times larger than all fossil fuel we now extract in a year.
Namibia Brewers Ltd. is the first company to commit to building a commercial plant based on zero-emissions principles. To do this they are building the zero-emissions system around the brewery. As part of the recycling process for grain, earthworms are used to extract the protein from the used grain. The earthworms eat the grain, converting vegetable protein into animal protein. The worms are then fed to chickens as a high-quality feed - the chickens love it - and in turn the chickens are sold.