Food waste that is sent to landfill decomposes to produce potent greenhouse gases. Instead, if recycled through composting, food waste can be used to produce valuable biogas, compost and soil conditioners.
When food scraps are sent to landfill, they decompose to produce methane, a greenhouse gas with more than 20 times the global warming capacity of carbon dioxide. Decomposing food scraps in landfill are also a potential source of organic leachates that can contaminate surface and ground water.
Food waste is estimated to cost the Australian economy around $20 billion each year. Australian consumers throw away around 3.1 million tonnes of edible food a year. Another 2.2 million tonnes is disposed by the commercial and industrial sector.
If food waste is recycled, the valuable organic matter and nutrients contained within them can be recaptured. Methane and other biogases can also be captured and used to generate electricity.
Food waste recycling collection services for businesses are provided by a number of commercial operators and local councils. The types of food waste accepted varies, so check with your local operator. Typically, items such as fruit and vegetable peelings, post-consumer left-overs and coffee grounds are accepted. Meat off-cuts and grease-trap sludge from commercial kitchens may be less commonly accepted.
Small businesses may consider having a worm farm or composting bin in the workplace, allowing them to compost their own lunch leftovers or scraps. Many local councils and community groups provide information and run workshops on worm farming and composting.
Hotels, restaurants and other large food service establishments may consider installing an industrial/commercial on-site composter. For more information on equipment to sustainably dispose of food organics visit Recycling Equipment Catalogue
For information on buying and using recycled organic products, or for more detailed information on composting, visit Compost for Soils.
The most common method of composting food waste in Australia is aerobic windrow composting (also called hot composting). In this process, food waste is mixed with other organic waste like wood chips or paper to before the material is formed into ‘windrows’ or mounded rows. The windrows are regularly turned and managed to optimise aerobic breakdown of the organic material (microbial breakdown of organic material in the presence of oxygen).
Another popular process that uses aerobic decomposition is in-vessel composting. This is similar to windrow composting, but the conditions can be more carefully controlled and the process is accelerated.
Biogas, including methane, is produced from anaerobic decomposition of organic waste (microbial breakdown of organic waste in the absence of oxygen). There are around 60 biogas generation facilities in Australia, producing biogas for electricity generation.
The solid material that is produced from composting is used as compost, mulch, potting mix, soil fertilisers and other soil conditioners. The liquid material that is produced from in-vessel composting and anaerobic decomposition is also used in soil conditioners, including liquid fertiliser that can be injected into the soil.
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