Co-composting is the controlled aerobic degradation of organics, using more than one feedstock (faecal sludge, excreta, organic solid waste, etc.). Faecal sludge has a high moisture and nitrogen content, while biodegradable solid waste is high in organic carbon and has good bulking properties (i.e., it allows air to flow and circulate). By combining the two, the benefits of each can be used to optimize the process and the product. Other organic materials, which can be used or subjected to co-composting, comprise animal manure, sawdust, wood chips, bark, and slaughterhouse waste, sludge or solid residues from food and beverage industry. See also compost or composting.