How Does Thing Biodegrade?

What makes something biodegradable? What is microbial decomposition and how does it break down our rubbish? Did you know that when you throw a soft-drink can in the bin it will take between 200 and 500 years to break down? Plastic dumped in landfi ll sites gets squashed down and sealed off by tons of earth. While you may think it then just breaks down like organic compost, it actually doesn’t because two vital ingredients for biodegradation are missing: oxygen and water. So to stop landfi ll sites getting bigger and bigger, and to prevent the planet from becoming a fl oating garbage site, humankind has had to come up with alternative ways to dispose of its waste. While recycling and reusing products again is one way to limit the amount of trash that we generate, there is also a way to make man-made materials more environmentally friendly: make them biodegradable. Through the actions of living organisms in the ground, such as algae, bacteria and fungi, the molecular structure of such materials can be metabolised (that is, broken down) into smaller, simpler substances that decompose far more readily. Traditional plastic is hard to break down as it comprises long, tightly bonded polymers. Plant polymers metabolise easily though. Starch from plants like wheat can be processed to make biodegradable plastic bags. Upon disposal, the grains of starch take on water and expand, breaking the material into tiny pieces that are more easily decomposed.