Organic waste is a type of biodegradable waste of plant or animal origin, containing mainly carbohydrates, proteins, fats, etc. Organic waste comes from expired food, spoiled fruit and vegetables, catering waste, slaughterhouse waste, etc. Normal landfill disposal is not only wasteful but also polluting (the methane gas produced by anaerobic decomposition is a greenhouse gas 20 times worse than carbon dioxide). The use of shredders to reduce the size of organic waste and make compost, substrate for biogas plants or for the production of feed is now a popular method of disposal.