The FAQs of Recycling with Science-Based Answers

 In Blog, Blogs

To the novice recycler, an unorganized heap of used packaging poses a daunting leap into unchartered territory. While the majority of people are aware of the three golden oldies of recycling (paper, glass and tin), technology has evolved with the packaging of regular household items.  With seven different types of plastic and an array of mixed-material packaging, figuring out what goes where can be confusing at first.  Fortunately, you can find all the ins and outs of recycling right here.

First, however, let’s take a step or six backwards. The nearing climate crisis was predicted long before hippies were chaining themselves to trees in the 1970s. To be exact, information about global warming came to light when Jean Fourier produced numerical calculations in around 1820. Fifteen years later, Ralph Waldo Emerson published Nature, an essay urging humanity to limit expansion into the wild places.

Since then, a slew of warnings and information has emerged, most of which has been ignored or flat-out disregarded. The result is that we are now facing a double-edged sword – the threat of the rising climate coupled with a global pandemic. Instead of waiting for the authorities to impose laws that make recycling mandatory, perhaps it is time to take matters into our own hands.

In the UK, a large percentage of households benefit from a collection system which has still fallen short of the government’s green goals. It may seem odd that a nation with such impeccable service has not yet managed to recycle 50 per cent of the country’s waste; the problem is, however, that recycling is complicated.

What materials can be recycled?

From a scientific perspective, it is technically possible to recycle a wide range of materials in addition to the standard paper, glass and tin. For the record, the term ‘paper’ refers to both paper and cardboard.


It should be noted, however, that not all local regions of the UK offer the same services. Depending on your local council, you may benefit from a municipal collection team or you may need to drop off waste to your nearest recycling depot. You will need to find out from your local recycling service exactly which materials can be recycled by their plant. From a technical point of view, it is scientifically possible to recycle the following materials:

  • Glass
  • Paper/Cardboard
  • Tetrapaks (Juice or milk cartons)
  • Tin (Aerosol cans, soda cans, tinned food cans, foil, bottle caps/wine lids)
  • Seven different types of plastic*:


  1. PET/Polyethylene Terephthalate
    (Soda bottles, yogurt/peanut butter containers, salad dressing/vegetable oil bottles, ziplock bags)
  1. HDPE/High Density Polyethylene
    (Margarine/ice-cream tubs, plastic bottle caps, milk cartons, juice bottles, garbage bags, wraps and films, certain bottles, disposable gloves)
  1. PVC/Polyvinyl Chloride
    (Cooking oil bottles, pipes, flooring, plumbing accessories, doors and windows)
  1. LDPE/Low Density Polyethylene
    (Bread bags, bags from breakfast cereals, wrappers from six packs, zip-lock bags, trays and general purpose containers)
  1. PP/Polypropylene
    (Straws, battery cases, street food tubs, selected bottles such as ketchup, plastic cutlery, tubes, filaments and bags)
  1. Polystyrene/Styrofoam
    (Takeaway coffee cups and deli trays, insulation, furniture, cabinets, CD and DVD cases, peanut packaging and surfboards)
  1. Miscellaneous
    (Nylon, fiberglass, polycarbonate, polylactide, acrylic, acrylonitrile butadiene and styrene)

* It is imperative to check the numbering on specific plastic items, as certain manufacturers mix plastics and this can cause problems in the recycling process. You can find the coded number inside the plastic recycling emblem (three arrows in the shape of a triangle).

Can different types of paper and cardboard be recycled together?

Most paper and cardboard is made purely from trees, meaning that it is biodegradable and will decompose naturally if left to its own devices. The main reason that paper is recycled is to conserve natural resources used in the production process. Additionally, it frees up space in the landfills for materials such as plastic that are not easily recycled.

When organic materials such as cardboard end up in the landfills, the compact conditions cause the decomposition process to emit the greenhouse gas, methane, so it is important to ensure that these are recycled.

It is safe to group colourful papers and cardboards, as well as waxy cardboards, all into the paper category. However, those new to recycling may notice certain cardboards seem to be coated in a shiny layer of plastic. If you have ever hesitated before chucking this foreign-looking substance into the ‘paper’ section, you would be correct to assume that it falls into the trash category. When plastic is mixed with cardboard, as is typically seen in light-bulb packaging, it cannot be processed with either of its parent materials.

What does the recycling process involve?

Depending on your local council or recycling depot, the batches of recycling are sorted either manually or by machinery. In the UK, most recycling facilities use conveyer belts and digital scanners that pick up what material an item is made from and thus designate it to the correct category.


Non recyclables are removed and the materials are separated using trammels (screened cylinders). The trammels hover over the conveyer belt and consist of layered cylinders designated to each category. For example, the 45mm trammel will deal with the glass, while the 160mm trammel will handle the paper, cardboard, plastic and metal. The latter are then sorted with a ballistic (vibrational) sensor.

After the ballistic sensor has separated the paper, card, metal and plastic, optical scanners are used to separate the plastics by colour. Magnets are used to sort the tins and steel, while an eddy current separator emits a magnetic field that sends aluminum to a designated area.

For this reason, it generally will not cause a massive issue if you accidentally throw the wrong type of plastic in with the rest of the mix. However, it will cause a serious issue if you don’t clean the recycling; this can result in entire batches being contaminated and sent to the landfill. Cardboard and paper with grease stains should be composted instead of recycled.

What causes contamination of the recycling process?

Due to the fact that unclean items can contaminate the recycling process, it is necessary to clean materials before including them in the mix. The items do not need to be cleaned like regular dishes with soap and a sponge; just a quick rinse will do the trick. The heat process can burn off small traces of food or milk (which is why soap is not required).

However, if there is residual food (or beverage) stuck to the item, such as soy milk at the bottom of a carton, you will need to give it a bit of a scrub. Oils or oily substances may need boiling water to remove the majority of the foodstuff. To make this extra eco-friendly you could always use the leftover dishwater for this job.

Additionally, items that are incorrectly disposed of can slip under the radar of digital scanners, causing masses of recycling to be sent to the landfill. With the recent advances in biodegradable packaging, a number of citizens have mistakenly assumed that compostable cardboard can be recycled along with the paper category. Due to the fact that paper and cardboard can only be recycled between five and seven times, this can lower the quality of the end product.

When it comes to biodegradable plastic though, this can cause serious issues when thrown in with regular plastic. Bio-plastics are made from organic materials, an entirely different substance to the man-made elements of traditional plastic.

Can I recycle electronics (e-waste)?

You can recycle electronics, but not in the same way that you dispose of regular household trash. The fact that electronics are sophisticated devices made up of various different materials makes the recycling of e-waste a specialised field.


Additionally, e-waste or electronic waste, may contain toxic elements such us mercury, lead, beryllium and polyvinyl chloride. These materials are highly toxic to both the environment and humans. When these items end up in the landfills, harmful chemicals are leached into the earth which causes an imbalance in the eco system.

It is not only possible but a legal requirement for all electrical and electronic equipment companies to provide a means for customers to safely dispose of old products. This involves offering some form of ‘take-back service’ which can either be found in store or at an alternative venue.

The organisation will then arrange for the recycling of your product which involves salvaging certain materials from the items such as gold, copper, and other reusable elements. The rest of the device is then shredded and remade into a new product, preserving natural resources and reducing carbon emissions.

If plastic can be recycled, then why is it such a massive problem?

Although most plastic can be recycled, the majority of plastics are rarely recycled by local authorities and depots. Just as glass cannot be processed in the same batch as paper, the different types of plastics cannot be lumped into the same category.

Each of the seven types of recyclable plastics undergoes a separate recycling process which requires different machinery and enough space to house the equipment. Additionally, each process is expensive, highly complex, and can does not result in the same quality as the original plastic item. In terms of profit, it simply does not make sense to recycle plastic.

For this reason, the UK actually ships the majority of plastic abroad to be recycled (burning fossil fuels and leaving a deep carbon footprint). It is incredibly rare for local recycling plants to offer the recycling of every material – specifically for all seven types of plastic. At most, the municipal recycling team will typically collect two types of plastic which are easier to recycle.

According to the ENFrecycling directory, there are 83 plastic recycling plants in the UK, of which less than 10 process the full range of plastics. Unfortunately this means that many households are left with at least five different types of plastic which must either be thrown in the trash, or heroically stashed for a trip across the country.

Unsurprisingly, most citizens choose the waste bin over hiring a trailer and taking a road trip to the UK’s fanciest plastic depot. This results in UK households throwing away approximately 40kg of plastic per year – the equivalent of ten standard recycling bins.

Due to the fact that the majority of plastics take about 500 years to decompose, this means that plastic is slowly spreading beneath the radar, taking up space that will ultimately run out. Additionally, even if plastics do eventually ‘biodegrade’ after five centuries, during that timeframe the material leaches toxins into the ecosystem that cause permanent harm to the environment.

How does recycling benefit the environment?

Recycling is beneficial for its preservation of natural resources, by optimizing existing raw materials, modifying them and reusing them. This has the additional benefit of a reduced carbon footprint in terms of production and manufacture, as well as emissions from landfills.


By preserving natural resources, recycling reduces air and water pollution. Recycling reduces the amount of waste being sent to landfills which has an impact on transportation emissions. While recycling is not the best strategy for reducing one’s carbon footprint, it still reduces the rising climate and benefits the eco-system as a whole. For example the energy saved from recycling just one glass bottle, is enough to power a light-bulb for four hours!

All in all, recycling is a good strategy for the protection of the environment and worth investing in. With collection services and drop off points, recycling is incredibly easy and simply requires a small change in habits. Instead of throwing everything in the bin, without a thought of where it may end up, try to keep the environment in mind every time you dispose of a waste item.

If you are unsure whether or not your local collection team will recycle a certain item, you can take these queries to the municipal managers. In time, you will master the art of recycling and as a result your daily existence will feel lighter and more pure. Whether or not you believe in Mother Nature or karma, from a scientific perspective recycling conserves energy and plays a role in rebalancing the eco-system.

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