144 Fun Facts About Recycling

Which furnace makes new steel mainly by melting scrap instead of smelting ore?

Electric arc furnace: it melts scrap with an electric arc instead of smelting ore in a blast furnace, which helps make steel one of the world's most recycled materials.

What term describes converting waste into new materials of lesser quality than the original?

Downcycling: in a 1994 interview Reiner Pilz complained that demolition crews smashed old bricks into rubble and called it recycling. 'I call it downcycling,' he said.

What is a recycling system called where paper, plastics, metals and containers all go in one collection bin?

Single-stream recycling puts everything in one bin and leaves the sorting to machines later; more households take part, but more of what they put out arrives too dirty to sell.

What policy makes manufacturers pay for collecting and recycling their own goods once customers discard them?

Extended Producer Responsibility moves the cost of dealing with worn-out goods from town halls to the firms that made them, which gives those firms a reason to design products that are easier to recycle.

A notebook labelled '100% post-consumer recycled' is made from which source of paper?

Used household paper: 'post-consumer' means the paper has already served a customer. Mill offcuts routinely go straight back into the pulp, so they are often not counted as recycled content at all.

William McDonough, co-author of the 2002 design manifesto Cradle to Cradle, works in which profession?

Architecture: McDonough wrote the book with the German chemist Michael Braungart, and they had it printed on pages made from plastic resin instead of paper, so that the book itself could be recycled.

What is the main danger when a lithium-ion battery is crushed in a bin lorry or at a sorting plant?

Fire: a crushed cell short-circuits and can burn fiercely, which is why recyclers drain large packs or shred them under inert gas, and why loose batteries should never go in a household bin.

Paper cannot be recycled for ever because each trip through the pulp mill does what to its fibres?

Shortens them: the US Environmental Protection Agency puts the limit at five to seven rounds, after which the fibres are too short to bond into a new sheet.

Which of these materials can be recycled again and again without any loss of quality?

Glass melts back into the same glass every time. The catch is colour, which survives the furnace, so clear, brown and green bottles have to be collected separately.

Recycling which material saves about 95% of the energy needed to make it from scratch?

Aluminium: smelting it from ore devours electricity, but remelting old metal needs only about 5% as much, which is why roughly three-quarters of all the aluminium ever made is still in use.

Which paper item is rarely recycled because of its thin plastic lining?

Coffee cups: the plastic lining is hard to separate from the paper, and British MPs reported in 2018 that fewer than one in 400 of the 2.5 billion cups used there each year was recycled.

HDPE, the plastic stamped with resin code 2, usually makes which household item?

Milk jugs: HDPE is stiff and strong for its weight and shrugs off most solvents, which is why the same plastic is trusted with bleach and detergent.

Before an old fridge is shredded, recyclers must first capture what?

Its coolant gases: older fridges used CFCs that eat the ozone layer, and their replacements are powerful greenhouse gases, so the law requires them to be drawn off before the fridge is broken up.

Carmen Hijosa's leather substitute, used in shoes and handbags, is made from the waste leaves of which fruit?

Pineapple: Hijosa took the idea from the Philippines, where the leaf fibre is woven into traditional shirts, and the leaves left after each harvest would otherwise be burned or left to rot.

What recycling method heats plastic waste without oxygen to break it into oil, gas and char?

Pyrolysis: with no oxygen present the plastic cannot burn, so the heat instead breaks its long molecules into oil, gas and char that can be refined into fuels and chemical feedstocks.

Shredded old tyres are widely recycled as the springy infill of which sports surface?

Artificial turf pitches: the rubber crumb is worked in between the plastic fibres to cushion the surface, whereas early AstroTurf was little more than a short-pile carpet.

What was the WWII practice of households handing in metal, paper and rubber usually called?

Salvage: America's 'Salvage for Victory' drives even collected kitchen fat, because the glycerine extracted from it went into explosives; Britain ran a National Salvage Campaign of its own.

Which plastic, recycling code #3, is used in pipes and window frames but rarely recycled curbside?

Polyvinyl Chloride (PVC) is also the vinyl of records. Sorters keep it apart because its chlorine gives off an acid gas when it is melted with other plastics, which ruins the batch.

Food trays of which colour are often rejected for recycling because sorting machines cannot detect them?

Black: the carbon-black pigment hides the tray from the plant's sorting machines, so it ends up among the rejects; makers have responded with black pigments the machines can detect.

Which heat-resistant plastic, resin code 5, is used for microwavable containers and bottle caps?

Polypropylene (PP) does not melt until about 160 °C, so it survives the microwave and even the steam sterilisers that hospitals use, which is why laboratory and medical plasticware is made of it.

Which plastic, recycling code 6, is used for disposable cups and foam packaging?

Polystyrene (PS) foam is about 95% air, so a lorry-load of it holds very little plastic, and very few kerbside schemes think it worth collecting.

Which code-7 plastic, used in CDs and older baby bottles, is made from bisphenol A?

Polycarbonate is made from bisphenol A (BPA), and once BPA was found to leach out, the US, Canada and the EU banned it from baby bottles; CDs and DVDs are moulded from the same clear, tough plastic.

What nickname is given to the tiny pre-production plastic pellets that often wash up on beaches?

Nurdles are the small pellets that factories melt down to make plastic goods; when the cargo ship X-Press Pearl sank off Sri Lanka in 2021, billions of them washed onto the island's beaches.

What happens at a materials recovery facility, known in the trade as a 'murf'?

Mixed recyclables are sorted there: screens, magnets and scanners split the paper, metal and plastic, which are then baled and sold to manufacturers as raw material.

Nearly all of which metal in old car batteries is recovered and cast into new ones?

Lead: old car batteries are America's most recycled consumer product, with 98% or more collected, and smelters have recast their metal into new batteries in a closed loop for about a century.

Used cooking oil is most commonly recycled into which fuel?

Biodiesel: reacting used cooking oil with methanol turns its thick fats into light methyl esters, which are thin enough to burn in an ordinary diesel engine.

Which kind of household light bulb contains mercury and so has to be handed in separately?

Fluorescent: the mercury vapour inside escapes when the glass breaks in a bin or dumpster, so many governments ban these bulbs from household rubbish and stores collect them for recycling.

Plastic fragments smaller than five millimetres across are classed under what name?

Microplastics: sunlight and waves grind floating litter into ever smaller pieces, and the fragments have since turned up in sea salt, seafood and drinking water.

In the European Union's waste hierarchy, which option sits at the top as the most preferred?

Prevention tops the hierarchy because waste that is never made needs no collecting, sorting or processing; reuse, recycling and energy recovery follow in that order, with disposal last.

What does the numbered triangle stamped on plastic products actually tell you?

What the item is made of, meaning its resin type: the code says nothing about whether it can be recycled, which is why a 2013 revision swapped the confusing chasing arrows for a plain triangle.

Re-melting thermosoftening plastic into new items, without altering its chemistry, is called what?

Mechanical recycling simply washes, shreds and re-melts the plastic; doing it repeatedly is hard because polymer chains shorten and contaminants build up with each cycle.

Batteries are collected separately from household rubbish partly to keep which pollutants out of soil and groundwater?

Heavy metals such as cadmium and mercury can leach from dumped batteries, which led the United States to phase mercury out of household batteries by law in 1996.

At a modern recycling plant, plastics are separated by polymer type using what technology?

Infrared optical sorting: each polymer reflects its own near-infrared signature, so scanners can tell one plastic from another on a moving belt and air jets blow each type into a separate stream.

An economy built on leasing, repairing and refurbishing products to keep them in use as long as possible is called what?

Circular: the record-breaking sailor Ellen MacArthur, struck by how her boat's finite supplies mirrored the planet's, set up a foundation in 2010 to promote the idea.

Which of these items do most kerbside recycling schemes refuse to collect?

Plastic bags wrap around the rollers at the sorting plant and force it to stop the line, so most go to store drop-off points instead.

The earliest recorded paper recycling, in 1031, took place in which country?

Japan: in 1031 Japanese shops began selling repulped paper made from waste paper, the earliest recorded instance of paper recycling.

What is the term for deliberately designing a product with a limited lifespan to encourage replacement purchases?

Planned obsolescence: in the 1920s the Phoebus cartel of lightbulb makers agreed that bulbs should last 1,000 hours, less than half what the best managed, and fined members whose bulbs burned longer.

Which home insulation is made mostly from shredded recycled newspaper treated with borates?

Cellulose insulation is about 80% recycled newsprint, shredded and treated with borate salts as a fire retardant, then blown into attics and wall cavities.

Which US city made separating food scraps for composting compulsory for all residents in 2009?

San Francisco made sorting compulsory once it was clear that voluntary schemes would not be enough, and the food scraps now become compost for local orchards and vineyards.

The crossed-out wheelie bin symbol has been required since 2005 on which class of products sold in the EU?

Electrical goods: the mark means the item must be collected separately, and EU rules make producers fund the collection, so households can hand old appliances in free of charge.

Why are people asked to rinse food containers before putting them in the recycling?

To avoid contaminating the load: a single dirty batch can send otherwise clean material to landfill, the perennial weakness of mixed collection.

What is a programme where a manufacturer collects its own end-of-life products for recycling called?

A take-back system: laws requiring producers to take back packaging, batteries, cars and electronics exist across the EU, and remanufacturing returned goods can save up to 85% of the energy of making new ones.

Rotting food and garden waste in a landfill gives off which potent greenhouse gas?

Methane makes up about half of the gas a landfill gives off, and because it traps far more heat than carbon dioxide, operators sink wells into the waste to capture it.

Benjamin Law's 1813 process for turning rags into recycled wool is known by what name?

Shoddy: Benjamin Law of Batley, West Yorkshire, began grinding woollen rags into re-spinnable fibre in 1813, and the word survives as an insult for anything cheaply made.

In Cradle-to-Cradle design, what are materials that can safely return to the soil called?

Biological nutrients, such as untreated cotton or wood, can rot down harmlessly, so a shoe might pair a sole that returns to the earth with an upper of 'technical nutrients' that goes back to the factory.

The three chasing arrows of the recycling symbol are folded into which mathematical shape?

A Möbius strip: the twisted band has only one side and no end, a fit for materials that go round for ever. The designer drew it standing on its point; the sponsor turned it base-down.

Gary Anderson, who drew the recycling symbol for a 1970 design contest, was what at the time?

A university student: Anderson, 23, beat about 500 other entrants. The paperboard firm behind the contest later dropped its trademark claim, which is why anyone may print the symbol.

Which US senator proposed the nationwide environmental teach-in that became the first Earth Day in 1970?

Gaylord Nelson of Wisconsin borrowed the idea from the student teach-ins against the Vietnam War, and announced a national one on the environment for the spring of 1970.

Which US state passed the country's first 'bottle bill' in 1971?

Oregon: Richard Chambers, a salesman who picked up litter on his hikes, pressed legislators for a refund that would bring empties back to the shop, and bottles fell from 40% of the state's litter to 6% by 1979.

In Seinfeld's 'The Bottle Deposit', Kramer and Newman haul empties to which state?

Michigan, whose 10-cent deposit is double New York's 5 cents; Newman's scheme uses a Mother's Day mail truck bound for Saginaw, Michigan, dodging the rental fees that doomed Kramer's earlier attempts.

Which province set up Canada's first mandatory deposit-return system in 1970?

British Columbia's 1970 scheme, the oldest in North America, began with soft-drink and beer containers only, and has since been widened to almost every ready-to-drink beverage.

Which Australian state introduced the country's first container deposit scheme in 1977?

South Australia began its container deposit scheme in 1977 with a 5-cent refund, raised to 10 cents in 2008, decades before any other Australian state or territory followed.

Infinitum runs the national deposit scheme for beverage containers in which country?

Norway: drinks producers pay less environmental tax the more of their bottles and cans come back, a strong reason to make the scheme work, and more than nine in ten are returned.

TOMRA, founded in 1972, makes which recycling device?

Reverse vending machines take in empty bottles and cans and refund the deposit. TOMRA's grip on the market grew so tight that in 2006 the European Commission fined it for shutting rivals out of supermarkets.

The Green Dot packaging symbol was conceived by the environment minister of which country?

Germany: environment minister Klaus Töpfer's 1991 packaging ordinance made producers pay into a 'dual system' of yellow bags and bins, run alongside ordinary municipal collection and signalled by the Green Dot.

Which country's 'National Sword' policy banned imports of 24 categories of waste from 2018?

China had been taking nearly half of the world's recyclable waste, so when the ban began Western recyclables piled up and exporters rerouted them to Malaysia, Vietnam and Thailand.

The Basel Convention of 1989 restricts cross-border shipments of what?

Hazardous waste: the treaty answered an outcry over toxic waste from rich countries found dumped in Africa, as at the Nigerian port of Koko in 1988; radioactive material is left to the nuclear agency.

As of 2025, which country had signed the 1989 Basel Convention but never ratified it?

United States: the Senate consented to the treaty in 1992, but Congress never passed the law needed to carry it out, so the country has stayed outside a convention that almost every other nation has joined.

In 1988 the Khian Sea dumped Philadelphia incinerator ash in Haiti by labelling it as what?

Topsoil fertiliser: after more than a year of being turned away from port after port, the crew unloaded part of the ash at Gonaïves under that label, and later dumped the rest at sea.

What was the barge Mobro 4000 carrying in 1987 when three countries turned it away?

Ordinary garbage, more than 3,100 tons of it from New York: the televised saga ended with the load burned in Brooklyn, and it may have helped to push up American recycling rates afterwards.

Fresh Kills, once the world's largest rubbish dump, sat in which New York City borough?

Staten Island: Fresh Kills opened in 1948 as a three-year stopgap, took the city's rubbish until 2001, and its mounds were capped for conversion into Freshkills Park, almost three times the size of Central Park.

The 'zero waste' town of Kamikatsu sorts household rubbish into how many categories?

45 categories: residents wash and sort everything themselves at one collection centre, a habit that began when a dioxin law forced the town to shut its two small incinerators around 2000.

Which give-away network did Deron Beal start in Tucson in 2003?

Freecycle: Beal worked for a small recycling charity and tired of driving round to find homes for usable cast-offs, so he emailed a few dozen friends, and the list grew into groups worldwide.

TerraCycle's original product was fertilizer made with the help of which creatures?

Worms: TerraCycle began in 2001 selling liquid worm-casting fertiliser, a 'compost tea', packaged in used soda bottles only because founder Tom Szaky's young company couldn't afford new ones.

Who founded The Ocean Cleanup in 2013?

Boyan Slat was 18 when he founded it, a year after pitching passive ocean cleaning in a TEDx talk, and a crowdfunding campaign then raised over $2 million for the first engineering studies.

The Great Pacific Garbage Patch, reported by yachtsman Charles Moore in 1997, drifts between California and which islands?

Hawaii: the patch sits where the circling currents of the North Pacific gyre trap floating debris, and Moore sailed into it by chance on his way home to California from a yacht race.

Alang, where retired ships are beached at high tide and cut apart, is in which country?

India: at Alang, in Gujarat, the gently sloping tidal beach lets a ship be driven ashore under its own power, so no dry dock is needed, and workers walk out to cut it up once the tide falls.

Agbogbloshie, the notorious 'digital dumping ground', is in which African capital?

Accra: at the Agbogbloshie scrapyard in Ghana's capital, nicknamed 'Sodom and Gomorrah', workers burned cables to recover the copper; the authorities bulldozed it in 2021, but scrap workers later returned.

Cairo's Zabbaleen waste collectors feed their organic scraps to which animals?

Pigs: the Zabbaleen are mostly Coptic Christians, and when the government culled their herds in the 2009 swine-flu scare, rotting food piled up in Cairo's streets.

The UK's first waste incinerators, built in 1874 in Nottingham, were known as what?

Destructors: later ones put the heat to work, and at Cambridge an 1894 destructor burned the town's rubbish to raise steam for the engines that pumped its sewage.

In 1884, Eugène Poubelle made residents of which city sort waste into three containers?

Paris: as prefect of the Seine, Poubelle ordered the city's landlords in 1884 to give their tenants three covered bins, and Parisians took to calling the bins by his surname, now the French word for a dustbin.

Kitchener, Ontario, began kerbside recycling with a 1981 trial that gave households boxes of which colour?

Blue: the trial covered 1,500 homes, and the firm behind it chose the colour because it showed up best at the kerb and stood up to sunlight; the blue box now serves hundreds of cities.

Which New Jersey city became the first in the US to mandate recycling, in 1980?

Woodbury, in Gloucester County, made recycling mandatory in 1980; councilman Donald Sanderson's idea of towing a recycling trailer behind the rubbish truck let both be collected in one pass.

Gas captured from wells sunk into old landfills is most often used to do what?

Generate electricity: roughly six in ten of America's landfill-gas projects burn it in engines or turbines to make power, while the rest pipe it to nearby boilers and kilns or clean it up for the gas grid.

Scrap glass that is crushed and fed back into the furnace is known as what?

Cullet needs less energy to melt than the sand, soda ash and limestone it replaces, so every extra tenth of it in the furnace mix trims the energy needed by 2 to 3%.

Which process, first described by Justus Claproth in 1774, removes print from recovered paper?

Deinking: Claproth was a law professor, not a papermaker, and he worked out with a local mill owner how to get the printing ink out of waste paper.

Which family founded America's first paper mill using recycled rags, in 1690?

Rittenhouse: William Rittenhouse built the first paper mill in British North America in 1690 on Wissahickon Creek near Germantown, Philadelphia, pulping recycled rags and linen.

Of all the plastic waste produced up to 2015, roughly what share had been recycled?

9%: the 2017 tally by Roland Geyer's team found that more plastic waste had been burned (12%) than recycled, while 79% sat in landfills or the natural environment.

Which country imposed the first national ban on thin carrier bags in 2002, after devastating floods?

Bangladesh acted after the bags were found to have choked drains during the floods; Ireland chose a 15-cent levy the same year instead, and cut bag use by about 90%.

In the 2010s, Brazil led the world in recycling which item, recovering about 98%?

Drink cans: Brazil recovered about 98% of its aluminium drink cans through the 2010s, tens of billions a year, helped by catadores, informal collectors paid by weight for what they gather.

The Tokyo 2020 Olympic medals were made from metal reclaimed from what?

Donated mobile phones: Japan's public handed in old handsets and other small electronics at NTT Docomo shops and collection points, and the haul yielded the gold, silver and bronze the medals needed.

Battery recycler Redwood Materials was founded in 2017 by a co-founder of which company?

Tesla: J. B. Straubel, who helped design its early battery packs, started Redwood to turn worn-out batteries back into the copper foil and cathode materials that new cells are made from.

Dave Hakkens started the open-source Precious Plastic machine project in which country?

Netherlands: Hakkens began Precious Plastic as a student project at the Design Academy Eindhoven and gave the machine blueprints away, so that anyone could build a small recycling workshop of their own.

Catalytic converters are recycled, and stolen, for which precious elements?

Platinum-group metals: each converter holds small amounts of platinum, palladium and rhodium, and when rhodium neared $30,000 an ounce in 2021 the devices became a favourite target for thieves.

Which machine uses a spinning magnet to fling non-magnetic metals such as copper off a recycling plant's conveyor?

Eddy current separator: the rotor's shifting magnetic field induces electric currents in the metal, and those currents push back hard enough to throw it clear; steel is pulled out by ordinary magnets first.

PLA, the compostable bioplastic used in 3D printing, is usually made from fermented what?

Plant starch, usually from corn or cassava, is fermented into lactic acid and then polymerised; despite the green label, PLA breaks down only in hot industrial composters, not in a garden heap.

Polar fleece jackets can be spun from which recycled item?

PET bottles: fleece made from recycled drinks bottles went on sale in 1993, and because Malden Mills had chosen never to patent its original 1979 fabric, rival brands were free to copy it cheaply.

What term describes tossing doubtful items into the recycling bin rather than the rubbish?

Wishcycling: hopeful bin-filling with greasy boxes, hoses and odd plastics spoils the good material around it, and a spoiled load may be dumped instead of recycled.

Which organisation launched the 'Crying Indian' anti-litter TV ad on Earth Day 1971?

Keep America Beautiful, set up in 1953 by the American Can Company and Owens-Illinois, ran the ad; the weeping 'Native American' was Italian-American actor Iron Eyes Cody.

The first Repair Café, where volunteers fix items for free, opened in 2009 in which city?

Amsterdam: the journalist Martine Postma held the first Repair Café there on 18 October 2009, and by 2016 she had registered more than 1,000 of them around the world.

The Sulaibiya tyre graveyard, once the world's largest, was in which country?

Kuwait: the Sulaibiya pit held millions of worn-out tyres, and fires there in 2012 and 2020 sent up smoke plumes so vast that the later one could be seen from space.

The DuPont engineer who invented the PET drinks bottle was the brother of which Pennsylvania painter?

Andrew Wyeth: his brother Nathaniel patented the PET bottle at DuPont in 1973 and liked to call himself 'the other Wyeth', since father N.C. and brother Andrew were so much more famous.

Food cans were traditionally coated with which metal to protect the steel from the contents?

Tin: a 'tin can' is really steel with a thin skin of tin to stop it rusting, which is why magnets can pull food cans out of mixed recycling.

Which part of a retired wind turbine is the hardest to recycle and has often simply been buried?

The blades are fibreglass bound in resin, which cannot be melted and remoulded, so old ones have been cut up and buried, burned in cement kilns or reused as beams for footbridges.

Aboard the International Space Station, drinking water is partly recycled from which bodily fluid?

Urine is distilled in a vacuum still that spins like a centrifuge, because liquids and gases will not separate on their own without gravity.

By one medieval account, which fallen ancient wonder was sold as scrap and carried off on 900 camels?

The Colossus of Rhodes fell in an earthquake in 226 BC, and the chronicler Theophanes says Arab raiders sold its bronze remains to a merchant of Edessa in 653.

Which European country burns so much rubbish for heating that it imports other nations' waste?

Sweden burns about half of its waste in plants that warm city heating networks, and in 2014 it imported 2.7 million tons more to keep them fed.

Where do rubbish trucks play Beethoven's Für Elise to announce their arrival at collection points?

Taiwan's trucks also play Maiden's Prayer by the Polish composer Tekla Bądarzewska-Baranowska, and they switch to Christmas music for the holiday.

British designer Anna Bullus built a business recycling which common pavement litter into plastic?

Chewing gum dropped into her collection bins, dubbed gumdrops, goes to a Worcester plant that turns it into a raw material for new plastic products.

In World War II, American households were paid to hand in which kitchen leftover for making explosives?

Cooking fat gives off glycerine when it is processed for soap, and glycerine makes nitroglycerine; Americans handed in 711 million pounds of fats in four years.

At the Tokyo 2020 Olympics, athletes slept on recyclable bed frames made from which material?

Cardboard frames able to hold 200 kilograms were supplied for 18,000 Olympic beds, then sent to be recycled into other products once the Games were over.

Hundreds of retired New York City subway cars were dumped in the Atlantic off Delaware to form what?

An artificial reef named Redbird Reef, after the cars' nickname, drew so many sea bass and flounder that other states applied for the next retired trains.

Which brewer had a beer bottle designed in the 1960s that could be reused as a house brick?

Alfred Heineken ordered the 'World Bottle' after seeing empties littering a beach on Curaçao, an island where affordable building materials were scarce.

Which construction material is recycled at a higher rate than any other material in America?

Asphalt lifted from old roads is called reclaimed asphalt pavement, and it can be remixed and relaid on the spot without ever leaving the roadway.

Which animated robot spends 700 years compacting rubbish into cubes on an abandoned Earth?

WALL-E got his boxy body after Pixar's artists visited recycling stations to study how trash compactors work.

Which term describes transforming waste or unwanted products into something of greater quality or value?

Upcycling is also known as creative reuse, and the word first appeared in print in a 1994 article quoting Reiner Pilz.

Which term did Jay Westerveld coin in a 1986 essay about hotel notices urging guests to reuse towels?

Greenwashing fitted, he argued, because the hotels made little effort to cut energy waste while every reused towel saved them laundry costs.

Which term describes the cheap, trend-copying clothing model of retailers such as Shein, Zara and H&M?

Fast fashion is blamed for a mounting waste problem: by one estimate, a truckload of discarded textiles is buried or burned every second.

Which sportswear brand's Grind programme turns worn-out trainers into running tracks and playgrounds?

Nike began collecting old shoes in the early 1990s through Reuse-A-Shoe, and its granules have since covered over a billion square feet of sports surfaces.

Besides recycled bottles and jars, which raw material is the principal ingredient melted to make new glass?

Sand rich in silica is the main ingredient, and soda ash and limestone go into the furnace with it so that the mix melts at a lower temperature.

What do biologists call organisms such as fungi and bacteria that recycle dead matter into nutrients?

Decomposers in forests are mostly fungi, because only wood-decay fungi have evolved the enzymes needed to break down the tough lignin in fallen trees.

Which thrift-store nonprofit began in 1902 when a Boston minister hired the jobless to mend donated goods?

Goodwill traded as Morgan Memorial until 1915, when founder Edgar Helms was persuaded that the name of a Brooklyn workshop copying his methods was better.

The BBC sitcom Steptoe and Son followed a father and son working in which horse-and-cart street trade?

Rag-and-bone men collected unwanted household items to sell on to merchants, and rising scrap prices have since revived the trade, with vans replacing the horses.

Which large rubbish bin began as the trademark of three Knoxville brothers in the 1930s?

Dumpster comes from the Dempster-Dumpster system, in which a truck mechanically lifts and empties standard metal bins; the name probably plays on the brothers' surname.

Qatar's Stadium 974, a modular venue built for the 2022 World Cup, incorporates 974 recycled what?

Shipping containers were chosen as a nod to the nearby port's industrial history, and their number matches Qatar's international dialling code, +974.

Mountains of imported used clothing have been illegally dumped in which desert?

Atacama, in northern Chile, is estimated to receive as much as 39,000 tonnes of illegally dumped secondhand garments every year.

Amager Bakke, a rubbish-burning power plant with a ski slope on its roof, stands in which capital city?

Copenhagen's plant, nicknamed CopenHill, also carries a hiking trail and a climbing wall on a sloping roof designed by Bjarke Ingels Group.

Which nation's public water utility purifies reclaimed wastewater and supplies it to users as NEWater?

Singapore's plants push treated wastewater through microfiltration, reverse osmosis and ultraviolet light, and most of it goes to industries that need very pure water.

What name is given to household wastewater from sinks, showers and washing machines, but not from toilets?

Greywater makes up about 65% of a typical household's wastewater, and once treated it can flush toilets or irrigate gardens instead of going down the drain.

Which craft mends broken pottery with lacquer and powdered gold, turning the cracks into a feature?

Kintsugi so charmed collectors that some were accused of smashing valuable pottery on purpose, just to have it repaired with golden seams.

Which fitness craze, begun in Scandinavia around 2016, combines jogging with picking up litter?

Plogging takes its first syllable from plocka upp, a Scandinavian phrase meaning to pick up, and it spread to other countries in 2018.

Which furry children's characters created by Elisabeth Beresford recycle the rubbish left on Wimbledon Common?

The Wombles got their name when the author's young daughter kept calling the place 'Wombledon Common' on a Boxing Day walk.

Mr. Trash Wheel, a googly-eyed machine that rakes floating rubbish from a harbour, works in which US city?

Baltimore's interceptor is driven by a water wheel, with solar panels pumping extra water onto it whenever the river's current is too weak.

Dozens of New York restaurants save which shellfish's empty shells so students can restock the harbour?

Oyster shells are left outdoors for a year to be cleaned by the weather, then seeded with baby oysters by pupils at a high school on Governors Island.

What name is given to the granules of ground-up scrap tyres spread under playgrounds and in artificial turf?

Crumb rubber is what is left once the wire and cord are stripped from a scrap tyre and the rest is ground down, and it cushions falls beneath play equipment.

Aircraft, bus and racing-car tyres are routinely given a fresh outer layer in which re-manufacturing process?

Retreading keeps about 90% of the original tyre by weight, and the materials cost roughly a fifth of those needed to build a new one.

Which heat-resistant glass, used for laboratory beakers and ovenware, must be kept out of bottle recycling?

Borosilicate glass has to stay out, because even a small piece changes how the molten mix flows when ordinary bottles are remelted.

Which metal was for decades recovered in bulk by recyclers from used photographic film?

Silver forms the image in traditional film, and until the 21st century used film was one of the leading sources of the recycled metal.

Which singer reworked 'Three Is a Magic Number' as 'The 3 R's' for the 2006 film Curious George?

Jack Johnson's soundtrack album became the first from an animated film to top the Billboard 200 since Pocahontas in 1995.

The Recycled Orchestra of Cateura plays instruments built from rubbish-dump scrap in which country?

Paraguay's young players perform on instruments such as a violin made from an old pan and a fork, and they have appeared in Lisbon, London and Hamburg.

What name did architect Michael Reynolds give his off-grid New Mexico homes walled with dirt-rammed old tyres?

Earthships are often horseshoe-shaped because rammed tyres are hard to turn through sharp right angles, and used cans and bottles serve as building materials too.

What name is given to the academic study of modern household rubbish, pioneered by William Rathje in 1973?

Garbology began when Rathje, an archaeology professor, set out to compare what people say about their rubbish with what they really discard.

Which waste-charging model bills households for the amount of rubbish they put out, like a metered utility?

Pay as you throw can charge by weight, by bag or by bin size, though studies have found that per-bag pricing also contributes to illegal dumping.

In the 'five Rs' of zero-waste living, which step comes before reduce, reuse, recycle and rot?

Refuse comes first because turning down things you do not need stops waste before it enters the home, and recycling is kept for whatever is left.

Which anti-consumerist lifestyle is best known for recovering discarded food from supermarket bins?

Freeganism blends the words free and vegan, though studies usually find that most people who raid bins for food do so to save money rather than as a protest.

What is a manuscript page called when its parchment was scraped clean and reused for a new text?

Palimpsest pages exist because parchment was costly, and modern imaging has recovered more than 80% of the erased writing in the one named after Archimedes.

In a garden heap, 'green' waste such as grass clippings is prized for being rich in which element?

Nitrogen-rich greens are balanced with woody, carbon-rich 'browns' such as paper and wood chips, ideally at about 25 parts carbon to one of nitrogen.

Which kitchen-scrap method ferments food waste in an airtight bucket using a specially inoculated bran?

Bokashi pickles scraps rather than rotting them: lactic acid preserves the waste, so the bucket barely warms up and gives off only a sour smell.

Which Mumbai district, a backdrop to Slumdog Millionaire, houses a huge industry recycling the city's waste?

Dharavi's recycling trade was reported in 2024 to employ about 250,000 people, working alongside the district's older pottery and textile workshops.

Which Brazilian city, famed for its bus rapid transit, once gave residents bus tokens for their waste?

Curitiba is a textbook case for city planners: it also built parks instead of canals to tame flooding and pedestrianised its downtown.

What is the fibrous residue of crushed sugarcane, now a popular material for disposable tableware, called?

Bagasse is also burned as a fuel for heat and electricity, and in countries such as India and Colombia it replaces wood in making paper.

In World War II, which garden and park fixtures were removed across Britain in a national scrap-metal drive?

Railings went from private gardens and public parks alike: Bath's Royal Victoria Park lost its original gates along with every railing around it.

At a paper mill, old paper is mixed with water, chopped and heated into a soupy mixture of fibres called what?

Pulp is then strained through screens to catch stray plastic, and fresh wood fibre is often added because the old fibres shorten with every cycle.

Which type of furnace melts scrap metal using current passed through graphite electrodes?

Electric arc furnaces reach around 3,000 °C at the arc, hot enough to make the lower ends of the electrodes glow as the scrap melts beneath them.