For centuries, until we started talking about the circular economy, waste was burned or piled in landfills. We talked about it in several articles in the history section of the portal.
But if on the one hand we were and, sometimes still today, found a hasty means to get rid of what was no longer needed, on the other hand we have never seriously posed the problem of the evolution of waste in the landfill.
Although today recycling activities are at the center of the attention of the political class and public opinion, it screeches in an annoying way as the percentage of the mass of waste that we recycle reaches about 10-12 percent, worldwide, of the products we discard each year.
The reasons for such a low share are of an economic, cultural, managerial and sometimes even criminal nature, with excellence in some countries reaching 70-80% of collected recycled materials, up to positions where separate collection is not in the vocabulary of everyday life.
But it is perhaps important to know what happens to the waste that ends up in landfills or rivers, which then flows into the sea, to realize that that enormous mass of waste it could be a propellant to reduce the carbon footprint and save natural resources, if only the recycling rate were higher.
The permanence in terms of time of buried waste is different from those that remain exposed to atmospheric agents or those that end up in the seas, this is because the sun, the water and temperatures act on them over time. So an exposure or not to atmospheric agents changes the average decomposition times of the materials.
But if we consider only the waste that ends up in a non-selective landfill, we can sketch some data that can make us think:
The plastic waste that ends up in landfills today is among the most varied, especially in those countries where separate collection is not applied. Their disintegration, non-biodegradability, as we have seen, depends in an important way on atmospheric agents, their composition and construction thickness, but we can say that the times for self-destruction of a plastic product can be counted on average in hundreds of years.
When we talk about this product we must consider that the volumes it generates as waste every day are really important. About 3.3 million tons of disposable nappies were collected in the United States in 2018 and, due to their composition of mixed plastics, their permanence in landfill ranges between 250 and 500 years before they decompose.
The packaging industry makes extensive use of aluminum packaging to contain liquids and foods, in fact the recycling data of these packaging in America in 2019 touched the 42.7 billion cans. Impressive volumes that give us hope, but still many aluminum cans end up in American landfills at a rate of about 10 billion a year in 2018. The decomposition time of a can is on average 80-100 years.
Glass is the natural element par excellence whose recycling is really simple but, despite this, the quantity of glass and ceramic objects that end up in landfills is very high. On the other hand, the decomposition times of the products are among the highest and we can consider it in several hundreds of years, but according to some it is an element that does not decompose at all.
Although one might think that paper has a short decomposition cycle due to the components that characterize it, today we find, especially paper for food packaging, waste composed of paper and plastic, which, when solidified, lengthen the decomposition times in an extremely long way.
Paper is one of the most important products of separate collection and its recycling has a direct impact on the environment because the use of recycled cellulose reduces the procurement of the virgin and consequently the felling of trees.
The decomposition times of an uncoupled paper product range from 2 to 6 weeks depending on the degree of humidity that affects the product but passes to tens of years if the product includes plastic couplings.
For ease of understanding we list some articles found in landfills and their decomposition times:
Cigarette butt: 10-12 years
Single filament fishing line: 600 years
Rubber soles of boots: 50-80 years
Foam plastic cups: 50 years
Leather shoes: 25-40 years
Milk cartons: 5 years
Compensated: 1-3 years
Cotton gloves: 3 months
Cardboard: 2 months
Polystyrene: It does not biodegrade
Nylon fabric: 30-40 years
Can: 80 years
Ropes: 3-14 months
Aluminum cans. 80-100 years
Isn't there really an alternative to landfill? Yes, there is.
Automatic translation. We apologize for any inaccuracies. Original article in Italian.