We are born, we live and we die. A quite simplified view on life. But during the whole mysterious circle of life there is something continually emerging: rubbish, a lot of rubbish. And a lot of our individual rubbish is known as Municipal Solid Waste (MSW). World Bank defines MSW as: “Waste that includes non-hazardous waste generated in households, commercial and business establishments, institutions, and non-hazardous industrial process wastes, agricultural wastes and sewage sludge. Specific definitions vary across jurisdictions.”7 One has to wonder: how much of this MSW do we actually produce? Well, it depends on several factors: age, cultural approach to consumer goods (hence nationality), income, and more.
Looking at the statistics gathered on such things, the MSW production per capita varies from an admirable low of 0.09kg/d in Ghana to the remarkable high in Trinidad and Tobago, 14.1 kg/d, with the MSW world average per capita at 1.2kg/d, which translates to 0.68 billion metric tons per year. This estimation is only likely to grow. Considering anticipated worldwide population growth, it is estimated that the worldwide MSW could triple by 2025, hitting the huge number of 2.2 billion metric tonnes per year.6
As might be clear from the numbers above, waste is cumbersome issue that humanity has to deal with, and although modern packaging makes it a bigger issue it has always been so. Throughout human history different strategies have been adopted, among which something more less akin to landfill is the oldest approach: dig a hole, put the unwanted waste in there, forget about it and let time do the rest. Before exploring this let’s first analyse another approach to trash, one which may be thought of as relatively new: recycling. Actually, recycling is not that new, one of the first recorded recycling activities was as early as 1031 in Japan (it is estimated the Chinese Empire was recycling paper even earlier than that). Due to the scarcity of the materials used for making paper in Japan at the time and the contemporary decline of the central administration of the empire during the Heian period, paper mills started to claim back waste paper, using it as the main source to produce new paper.9
Interestingly, human activity is central to recycling. We collect it, quite commonly via kerbside collection, we sort it (although more often than ever before this process is getting automatised) and we transform it into new resources, meanwhile saving natural resources and reducing emission of CO2.3
MSW is not a homogeneous entity but made of very different products: from tin cans to paper, from food leftovers to glass, from batteries to plastic bottles and so on. This brings us to one of the most crucial and laborious part of the recycling process: sorting. There are different ways of sorting waste and this particular process heavily affects cost effectiveness. Automated sorting processes become more affordable by the year, and also simplify the process, so they seem a positive step forward.2-3
Not all materials are the same, some are more economically valuable and sustainable than others. Recycling paper, tins, steel, glass, plastic and batteries are for example is cost efficient and environmental friendly. On the other hand, waste such as electronic components, like the very laptop used to write this article, are harder and more resources demanding to recycle, quite polluting too. Separating materials like silicon, copper and fibreglass is no easy task but allowing these components to end up in a landfill is not environmental friendly either and a bit of a waste (in the figurative sense of the word too). Unfortunately, it does not end here. Even among the MSW worthy to be recycled is not always easy. For example, paper makes a good recyclable source only according to which kind paper is processed. Cardboard is much more proficient to recycle than newspaper, in the first case the fibres are still elongated and usable, while in the latter the fibres are already reduced to a pulp, making the process much more laborious and expensive. What about glass? The type of glass everyone is looking for is the clear one. Being neutrally clear has many more possible reuses. But glass, especially bottles aren’t always clear, some are green, some are brown, some blue and so on. Great Britain, for example, is the biggest in importer of wine in the world, around 1 billion litres per year! Keeping in mind that the vast majority of wine bottles are green, hence the UK is struggling getting rid of a mountain of green bottles. Last but not least, plastics. There are so many kind of plastics, Polyamides (PA), Polycarbonates (PC), Polyethylene (PE) and Silicone to name just a few. All of them different, all of them have different values, making them more or less worthy to be invested in a recycling process.3
Which takes us back to landfill. This approach, digging a hole and leaving waste in it, might seem quite reckless at first, but how bad really? Well, let’s immediately be honest that, landfills are nasty, and no one wants them in their neighbourhood. According to studies it is hard to say if and how much exposure to landfill might have repercussions on health but they are not appealing places13. Furthermore they can create unpleasant leaky substances like leachate, which is toxic and quite dangerous, especially if it enters the water supply, and methane, a strong greenhouse gas. There are some secondary side effects as well: nauseous odors, unpleasant views, rat and seagull infestations, which create their own waste problems.
But is there another way of looking at landfill? Could such sites ever become a source of energy and materials?
Methane, a product of landfill and a dangerous greenhouse gas. But methane is also a valuable potential source of energy by combustion. Indeed, methane collection from landfills is becoming more common every year. Thermal energy can also be collected from landfills by applying methods similar to those used for geothermal heat collection. Last but not least, plastic in at such sites has been discovered to be well preserved due to the anaerobic environment. About eighty percent of aged refuse could be potentially be recycled after excavation, leaving a large capacity that could be regenerated for sustainable landfilling.15
In a similar vein, if landfill sites are properly remediated, they can be safely reused, reclaiming the space for urban use. There are several examples of this happening effectively in the UK, including Port Sunlight River Park.
Fig.1 Port Sunlight River Park
But is all this necessary? Some reports have suggested that perhaps we have space to accommodate landfill for the next millennia without any issue whatsoever.1-2 However, those studies were limited to regions of the world such as the USA where the amount of sacrificable grazeable land is much greater than it is in smaller countries by landmass, like the UK. Landfills also present a specific environmental risk where they are not well engineered to catch released methane.
Worldwide people are more aware of waste and the environment, with recycling having become a trend. This has raised the awareness of the environment, with even big brands expending themselves to reach zero waste, an almost utopian target3. Critically people are starting to think beyond recycling, towards reusing: using plastic bags more than once, refilling household cleaning products, and so on, with policy supporting this. Sweden is even introducing tax breaks to tackle ‘throwaway culture’ by cutting VAT on fixing everything from bicycles to washing machines12. This seems sensible if not essential, as resources are finite.
Recycling itself might not be perfectly efficient yet but changing the way industries pack their products, the infamous ‘Pringles factor’ is a leading example where a single can is made of three different materials (cardboard, plastic and metal), switching to products explicitly designed to be recycled at the end of their life cycle would drastically increase the efficiency of recycling and heavily reduce the amount of MSW daily ending up in the landfills3-10, making the utopia of a zero-waste society couple of steps closer.
- Tierney J. (2015) The Reign of Recycling, NYTIMES, https://www.nytimes.com/2015/10/04/opinion/sunday/the-reign-of-recycling.html
- Tierney J. (1996) Recycling is Garbage, NYTIMES, http://www.nytimes.com/1996/06/30/magazine/recycling-is-garbage.html
- Truth about recycling (2007), The Economist
- Giannelli S. Pioneering Italian Town Leads Europe in Waste Recycling
- Municipal Solid Waste, US Environmental Protection Agency
- P.Mudderidge (2015),Which Countries produce the most waste per person?, World Economic Forum
- MSW Definition, The World Bank
- E.Gabrianowsky, How Recycling Works
- J. Norman, Perhaps the Earliest Recycling of Paper, History of Information
- D. Gayle (2017), Product designers ‘must reduce Pringles factor’ to boost recycling, The Guardian
- J. Hopewell et al. (2009), Plastics recycling: challenges and opportunities
- R.Orange (2016), Waste not want not: Sweden to give tax breaks for repairs, The Guardian
- M.Vrijheid (2000) Health Effects of Residence Near Hazardous Waste Landfill Sites: A Review of Epidemiologic Literature. Environmental Epidemiology Unit, Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom
- R.J.Grillo (2014), Energy Recycling – Landfill Waste Heat Generation and Recovery, Springer International Publishing
- Y. Yujiang et al. Research on Composition and Recycle Value of Aged Refuse at Shanghai Refuse Landfill, Tongji University, Shanghai, China