I Know What You Binned Last Summer
When we throw away various pieces of waste and unloved rubbish, we don’t tend to think too deeply about what actually happens to them. Even if we do, our thinking only extends so far. Say you throw something into your big green waste bin. You wave a loving goodbye from the pavement as your beloved cast-offs are carted away by the timely binman and… never think about it again.
While the curtain has fallen on the story of you and whatever particular piece of rubbish you’re thinking of, there’s a whole encore going on behind the scenes. Most likely your item has ended up in landfill. Here is generally what the imagination whips up: an image of your discarded item (be it sock, nappy or old microwave) on top of an enormous and precariously stacked tower of other people’s crap. Sentenced to live out its days circled by gulls and playing host to a proud dynasty of rats. Forever.
Not necessarily, I’m afraid. Yes, after industriously quarrying the life out of the country, lots of enormous empty pits seemed a great place to throw our unwanted goods. But there came a point after a half century of joyfully tipping literally everything into a big pit in the ground, when we realised that those pits eventually filled. In even later years, we realised that never asking anyone what they were chucking into said pits was causing some problems no one had anticipated.
Harmful substances like hospital waste, batteries and pretty much everything else were seeping down through the soil. Rainwater fell on the pits and as it collected all those pollutants, it became a nasty liquid cocktail known as ‘leachate’. Leachate varies in its composition, depending on what is in the landfill but generally speaking it has a high ammonia content (giving a high, alkaline pH) because of the breakdown of organic material in the pit. When leachate seeps down into the water table and into the groundwater supply, it can be toxic. When it runs off into rivers it kills aquatic life and damages ecosystems.
A team of people must rigorously test water quality around old landfill sites continuously to ensure there are no pollutants leaking into the drinking water supply or surrounding water bodies. Some households have what’s known as private borehole, meaning they get their water straight from their own land rather than the mains supply. Where these boreholes fall close to old landfill sites, they too must be monitored.
Fish-killing cocktail aside, the breakdown of organic material in landfill sites also produces large quantities of carbon dioxide and methane (and we now know the latter is far more potent as a greenhouse gas). So, these vast filled pits were eventually acknowledged as spewing harmful gas and poisoning the local waters.We began to regulate what could be thrown into landfill, developing the network of recycling centres we see across the country today, hoping to limit the number of things making in into the pit and placing much stricter rules on what could be tossed. But these new protocols could not undo the damage of the past, and as time goes on this bacterial breakdown will continue long into the future. So how do we deal with these large areas spewing gases and leaking into rivers?
Enter here the army of people it takes to keep these pits from causing unnecessary harm. These are the same people who carry out the water quality checks, a truly versatile and essential, yet very underappreciated job. Old landfill sites which are no longer accepting waste are aptly known as ‘closed’ landfill sites. Over the years standards of newer landfills have been raised and many of these sites have been ‘lined’, essentially putting down a barrier membrane to stop water and gas escaping from the bottom and sides of the site before it starts to be tipped. Then, when tipping has been completed the site is ‘capped’ with several layers of soil, compact clay and a geomembrane, preventing the escape of these harmful gases and the infiltration of contaminated water down to the water table. To put it simply, if the pit is the bin then the lining is the very specialist bin bag, topped off with a lid (capped).
Simply bottling in the gases and leachate like this creates problems of its own, as when these gases are allowed to build up, they can cause fires under the ground if oxygen enters the soil. This means that networks of pipes must be installed, snaked across the site to allow the safe movement to gas which must be monitored at strategic points by specialists on a daily, weekly or less frequent schedule depending on how stable the composition of gases are. These gases used to be vented out into the atmosphere, however today they are used to power on site engines which generate electricity for the site and can be sold back to the grid.
Eventually enough waste in a closed landfill will be broken down that the site no longer produces significant gases and requires monitoring less and less frequently. Once capped, sites are often covered with soil and allowed to grass over. Many sites have good flower and tree coverage and provide homes for deer, rabbits and other wild species. To the untrained eye, they look more like nature reserves and you might never know you were standing on 60 years of rubbish. Some are even open to the public for walking, once they’ve reached a low and stable enough level of gas production and been reengineered to remove any potentially dangerous equipment. However, the ground will remain too unstable to build on and it will take decades to reach this more attractive state.
The alternatives to landfilling are equally controversial, incineration plants get an awful press and shipping our unwanted goods to developing countries to deal with is obviously immoral. Recycling is a popular and sensible method of dealing with our waste, but recyclable items don’t have an infinite lifetime and not everything can be recycled. So, what does that leave? Well, one of the best ways of dealing with waste is to simply not create it in the first place. Making sensible decisions about our consumption, not buying in excess and choosing materials that are recyclable or compostable can all go a long way towards reducing our waste. In essence, if you aren’t willing to stay and appreciate the effort that goes into the encore, you might want to consider whether you should be going to the show at all.