Food waste is often one of the first constituents of Municipal solid waste, up to 30% in Hong Kong. In Boston, 36% of what is currently thrown away is compostable. ⅓ of what New Yorkers throw away is food scraps and yard waste.
By diverting our food scraps, we help protect the environment by:
reducing the amount of waste ending in landfills or incinerated,
reducing greenhouse gas emissions by 50% *,
generating renewable energy or fertilizer,
reducing pollution.
Ways of recycling food waste
There are different ways of recycling food waste:
- thanks to a compost in a private backyard or in a facility,
- through anaerobic digestion.
Composting (like in a backyard) is the decomposition of organic matter in the presence of air (oxygen); it uses the natural activity of bacteria, fungi and other soil organisms to decompose organic materials and return them to the soil.
Anaerobic digestion processes food scraps without air (and most importantly oxygen). Most of the food scraps become clean energy through the production of methane. The remainder is water and trace nutrients.
How does composting work?
Composting is a natural process of recycling organic material, such as food scraps and yard waste. It produces a valuable fertilizer that can enrich soil and plants. Composting simply speeds up the process of decomposition by providing an ideal environment for bacteria, fungi, and other microorganisms from the soil (such as worms, sowbugs…). The organic waste is broken down and the resulting decomposed matter, which often ends up looking like fertile garden soil, is called compost. It is rich in nutrients and can be used for gardening and agriculture.
How does anaerobic digestion work?
The facility that collects the food scraps blends it into an organic slurry. The slurry is added to sewage sludge and goes into an anaerobic digestion tank. With the aid of bacteria, the anaerobic digesters convert the sludge and food into methane and solids. The methane is captured to make clean energy in the form of heat and electricity. Remaining solids are made into a nutrient-rich fertilizer.
This allows to process food scraps including meat and dairy, but also compostable containers (that couldn't go into a backyard compost) in some facilities.
In the U.S., the practice of digesting food waste at wastewater treatment facilities is more and more common in communities that collect curbside compost to process it along with sewage sludge.
Whatever process is available around you, it is important that you pay attention to recycling every little food scrap and other compostable material in the Food Waste or Compost bin in order to reduce your carbon footprint. Thank you!
Sources:
* https://www.drawdown.org/solutions/composting
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