When a landfill closes, the site, especially the groundwater, must be monitored and maintained for up to 30 years!Source: <a href="http://science.howstuffworks.com/environmental/green-science/landfill7.htmSo,">http://science.howstuffworks.com/environmental/green-science/landfill7.htmSo,</a> the bottom line is, in order for biodegradable diapers to be biodegradable you would need to compost them or flush them (the poopy ones cannot be composted).