How Landfill Works

For most of us, our understanding of how landfill works is framed by wheeling a bin out front once a week

At the same time, even the most ignorant among us must notice the increasing attention being paid to reuse, repurposing, recycling and generally avoiding sending stuff to landfill. There's very good reasons for all this noise about avoiding landfill and chief among them is space, contamination and methane.

The facts are that landfill sites are simply land that is filled with garbage, no matter how they get dressed up and everything after that is managing the problem of land filled with garbage - and trying to make the best of a bad situation.

We send a lot of rubbish to landfill - 20 million tonnes per year in Australia alone. That is a very large pile, even when you start with a very big hole. And the rubbish we send there is chemical ridden and also does not break down, at least not quickly, no matter how compostable or biodegradable it is. That's because the rubbish is compacted to save space and frankly not blow away, get pecked by birds or eaten by rats, so there's no oxygen. 

Modern landfills compact and bury waste in a complex system to minimise both the space they take up and their existence as a biohazard. Landfills are simply not designed to break down waste, only to store it. Rubbish does decompose slowly, but the problem is that because the environment is sealed with no oxygen, bacteria in the waste produces methane gas, one of the most potent greenhouse gases. (It is also  highly flammable and dangerous if allowed to collect underground - which is probably a good thing because that means systems have to be build to deal with it.)

This diagram from Carbon Fund shows the whole process pretty clearly:

Landfill is essentially a series of layers

To protect water systems from chemical leaching, the bottom of a modern landfill is typically lined with compacted clay dense enough to prevent liquids from penetrating it. On top of the clay, is a thick, high-density plastic liner.

As waste slowly decomposes it can produce liquid, which can also bind with rain and snow that falls on top of landfills. Perforated pipes are installed on top of the base liner to collect these liquids - known as leachate - and funnel them to treatment facilities, either onsite or at wastewater treatment plants.

Modern landfill systems collect the methane generated by decomposing rubbish in a layer of pipes placed above the solid waste layer. Methane is collected to sell as Natural Gas, turn it into electricity or burn as a source of energy. 

The main area of landfill you can see - the rubbish - is delivered and then compacted to take up less room. Every day, the new trash is covered with a layer of dirt which helps contain odors and deter pests. 

Once a section of landfill is full, it is capped with another liner made of high-density plastic. That liner is then covered with soil and vegetation is planted. The site continues to be monitored for at least 30 years to ensure the surrounding environment is safe from contamination. Eventually the sites are turned into parks, solar farms or open spaces.

Landfill waste doesn't just 'go away', it mounds up forever

Australians send around 20 million tonnes of waste to landfill each year.  Most of Australia's 600 official landfill sites are out of our sight and even our noses these days with odour, wind, animals controls to manage both bio hazards and our sensitivities. And yet, we need to extend our sensitivities to now sending stuff to them in the first place. 

Next time you buy something you don't need or are considering how to manage a piece of waste, it is worth considering how your waste is contributing to this big assed pile of chemical ridden rubbish.

Many councils run on site Tip Shops to reduce waste

Landfill is slowly reducing with more attention being focused on recycling. Items left at transfer stations are sorted into their relevant piles for the appropriate recycling contractor. Most landfill sites also have shops reselling items in good condition as well.

Fun family outing - take your kids to a landfill

Take your children to the local garbage tip and transfer station and broaden their understanding of what happens to unwanted stuff and just how much of it there is when you see a whole city's waste in one place.  It is hard to imagine the size and sheer waste at a landfill site without seeing it for yourself. 

Councils are very focused on the education of children as long term allies in the conversion of landfill into recycled and repurposed materials. Schools often take children on excursions to landfill education centres so it is worth checking with your child before taking them out, as they may already be going with their school and be able to offer you some schooling instead. 

You can visit transfer stations any time you have something to drop off. Young children are not allowed out of the car, but teens certainly are. Either way, the visit is worthwhile as they can see clearly what happens to different items.

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