Well, not actually a tank, but a Czech Army Field Kitchen. This short video by Kyle Farquharson and Jennifer Giesbrecht of the University of British Columbia Graduate School of Journalism interviews local Steven Forster and his unique food cart.
Notice, at about 1'10", the display of the different types of carrots being prepped for use. Steven is careful to use local and organic wherever he can when making chili. He operates under the name Opa's Suppenküche. and you can check out another video--showing how the tank is heated using green fire logs made primarily of used coffee grounds. He also serves into biodegradable and compostable bowls.And the chili looks pretty darned good too!