Posted: 31/12/2012 at 17:19
There are plenty of adverts for them, but I have never seen anything from anybody who has actually made good compost with one. They will be very heavy to turn when loaded and I wonder if they really do 'tumble' to compost rather than the contents just staying in one lump.
Might it be more satisfactory if one member of staff could make the compost off-site. Perhaps the pupils could bring in shredded paper, peelings (you can wrap them in newspaper and just chuck them in the compost), tea bags and coffee grounds, etc.
Or you could start a wormery. Or several. Good luck, growing helps with so many skills.