The liners are biodegradable, not certified compostable. They are designed to contain soiled feces and urine, so should be treated more like spoiled meat. Recommendation is disposal in general waste bin, not compost (green) bin. Soiled cat litter is not suitable to dispose of in a compost bin. The Robot helps the enviroment by reducing litter waste and concentrating the amount needing disposal to just the soiled litter, but that makes it unsuitable to compost as well.