I've always been confused on the biodegradable nappy front.
My boys pampers is non-biodegrable, goes into landfill and sits there doing nothing much for 100 years
My mates boys biodegradable nappy, goes into landfill, degrades, creates methane, which escapes into the atmosphere and does it's bit as a greenhouse gas.
Which is best?
nb, one of the funniest things I've seen in the last couple of years was a bloke who tried to compost "biodegradable" nappies at home. The sight of him racking through a years worth of old nappies to remove the non-degradable tags and stretchy bits was something to see. It appeared that they were only 70% biodegradable!

