In this article, you’ll learn why even biodegradable organic waste needs special treatment. We look at the threats organic waste can pose when sent to landfill, and give examples of how the problem is being tackled. Read on to find out more!
“Organic waste” is all food and garden waste that has the potential to decompose and become fertile soil. Almost half the waste we produce is made up of food scraps and other organic leftovers. The negative impact of organic waste starts when someone throws their organics into a mixed waste bin. And it’s even worse if you mix organic with recyclable material, because then that recyclable waste becomes contaminated—ending up in landfill too. Additionally, as the organic waste starts decomposing in the bin, it will smell. The unpleasant odours attract flies, rats, bugs and mosquitoes which spread diseases.
And of course, the problem doesn’t disappear just because the rubbish truck takes away the smelly waste—it just gains momentum. In landfill, bacteria from biodegradable waste mixes with chemicals from other waste, multiplying rapidly. Add in water and it forms a toxic leachate, which without proper filtering systems seeps into groundwater and soil. Leachate can poison aquatic life and crops, and directly affect the health of people living nearby. Unfortunately, disposing of organic waste by landfill still remains the cheapest and the most widespread global method of waste management.
Lack of oxygen in landfill affects the decomposition of organic material. This means the breakdown process becomes anaerobic. And anaerobic decomposition of organic waste generates methane—a potent greenhouse gas, with around 20 times more impact on climate change than carbon dioxide. As an additional risk, if landfill gas isn’t pumped out, it may cause fires which lead toxic substances to release into the air and cause accidents on-site.
Organic waste is full of nutrients that can be returned to the soil as fertilisers. While this remains a missed opportunity for most countries, there are successful examples showing that industrial composting yields results.
Austria is a leader in composting; it accounts for 33% of their waste management. Home composting is actively promoted by the government wherever possible which reduces the cost and negative environmental impact of waste transportation. Otherwise, citizens can choose between a door-to-door separate organic waste collection or alternative civic amenities to deal with their bio-waste. Any collected organics are processed into high-quality fertiliser at more than 400 composting facilities around the country.
As a rule, you can compost the following things at centralised composting facilities:
Cooked meal leftovers, animal products (meat, bones, eggs, dairy) and animal litter are potentially compostable, but certain composting services may not accept them. Before you use one, check what they accept in advance. And something to be aware of wherever you compost, is that vacuum cleaner waste usually contains microplastics, so can’t be included.
Some composting plants also collect compostable plastic packaging. New Zealand is one of the few to do so, but it isn’t widespread. So whilst compostable plastic has benefits, it isn’t a magic bullet.
At a composting plant, all organics go through a long process of transformation to become fertiliser. Mixed organics are shredded and put into windrows (long rows), vessels or aerated static piles. The future compost is watered and turned over regularly to get enough air, with microorganisms, heat, moisture and oxygen helping the breakdown process.
After the active phase is done, the compost “rests” at a lower temperature and is then screened to make sure it’s safe for use. The duration of the process depends on the technology used. When ready, the fertiliser is used for orchards, farms and gardening.
But not all bio-waste is sent to industrial composting plants. Sometimes biogas plants use its ability to produce methane. Here, waste is digested anaerobically by microbes to generate methane in special reservoirs. Almost any organic waste suits this process. This renewable energy source is suitable for replacing natural gas in transport, heating or electricity. What’s more, there is organic residue leftover after digestion, which can be used as fertiliser. As they say, “kill two birds, with one… waste”..!
Centralised composting is a good way of dealing with your organic waste. But only if you can’t compost at home. Composting on-site where the waste is generated adds no extra cost or environmental footprint through transportation. Our next articles will convince you that home composting is easy as pie!