Most of us have thrown away uneaten leftovers, spoiled fruit and vegetables or food products that have passed their best-before date. Wasted food is not only a waste of money, it’s a waste of the resources used to grow, harvest, transport, process, store and distribute food.
Why Recycle Food?
No matter how careful we are, we’ll always have some unavoidable food scraps such as vegetable peelings. Even here, we can reduce our impact by recycling food scraps for compost. When food scraps are sent to landfill, they decompose without oxygen (anaerobically) to produce methane, a greenhouse gas with over 20 times the global warming capacity of carbon dioxide. Decomposing food scraps are also a potential source of leachates (liquid that drains from landfills) that can contaminate surface and ground water. If food scraps are composted, the organic matter and nutrients they contain can be reused as fertiliser. Properly composted food scraps are a valuable resource. In some commercial composters, methane and other biogases can also be captured and used to generate electricity.
What Happens to Food Waste?
Composting is the biological breakdown of organic matter (such as food scraps or garden cuttings) into humus or compost; a material containing stable yet readily-available nutrients. Microorganisms (such as bacteria and fungi) and microfauna (such as insects and worms) break down the organic material in the presence of oxygen. By controlling composting conditions such as the carbon-to-nitrogen ratio, temperature, moisture and aeration, we can influence the composting process. Compost is an excellent soil conditioner that improves soil fertility and encourages plant growth. Good composting practices also reduce of the amount of methane produced. A worm farm is a particular type of composting system where worms play the largest role in the decomposition process. Commercial composters may use a variety of specialised anaerobic composting systems to speed up the rate of decomposition and to capture any methane produced in the process. The methane can then be captured and used to generate electricity