Many developed and developing countries practice composting and anaerobic digestion of mixed waste or biodegradable waste fractions (kitchen or restaurant wastes, garden waste, sewage sludge). Both processes are best applied to source-separated waste fractions. While composting is often appropriate for dry feedstocks, anaerobic digestion is particularly appropriate for wet wastes.

Many developed and developing countries practice composting and anaerobic digestion of mixed waste or biodegradable waste fractions (kitchen or restaurant wastes, garden waste, sewage sludge). Both processes are best applied to source-separated waste fractions. While composting is often appropriate for dry feedstocks, anaerobic digestion is particularly appropriate for wet wastes.