hi there,
I too looked into this somewhere, try rollercoaster and search under the discussions for eco stuff. Im not sure this really works unless you have a huge garden and lots of space so smell doesn't get near house. Cant exactly remember much other than that but I went off the idea. Have decided to use re-useable/ washable ones with a liner you pop in the bin or is flushable down the loo and biodegrades. Easier I think in the long run, you just wash the nappy bit in the machine and refill with liner, at least the garden is kept poo free!!
Hope this helps
Muffinb