IB ESS SL Topic 7 — Solid Waste Paper 1 & 2 Core idea ~12 min read

What Counts as Waste

Almost half of what a household throws away was alive a few weeks ago — grass clippings, peelings, leftovers. It could rot down into soil in a matter of months. Instead most of it is buried, where it turns into methane. Understanding what is actually in the bin is the first step to fixing that.

📘 What you need to know

  • Using natural resources always generates waste, and waste can be classified by source or by type.
  • The three sources are domestic, industrial and agricultural.
  • Types you must know: e-waste, food waste and biohazardous waste.
  • Solid domestic waste (SDW) is the non-liquid waste produced in homes.
  • SDW contains a wide mixture of materials, which is exactly why it is hard to manage and recycle.
  • The volume and composition of waste vary over time and between societies.
  • Four groups of factors explain that variation: socio-economic, political, environmental and technological.
  • Wealthier societies generally produce more waste per person; lower-income societies often produce less but have less capacity to manage it.

Two ways of sorting waste

The same bag of rubbish can be classified in two completely different ways, and exam questions use both. Sorting by source asks where it came from. Sorting by type asks what it is made of.

Two labels for the same rubbish Every piece of waste has a source and a type BY SOURCE: WHERE IT CAME FROM domestic food scraps, packaging, broken items industrial chemicals, metals, factory by-products agricultural manure, crop residues, pesticide cans BY TYPE: WHAT IT IS MADE OF e-waste computers, phones, televisions food waste edible food thrown away biohazardous needles, blood products, lab waste An old phone from your house is domestic AND e-waste The two systems overlap, so always say which one you are using
E-waste matters because it contains toxic materials such as lead and mercury, so where it ends up is a health question, not just a tidiness question.

Sources of waste

SourceWhere it comes fromExamples
DomesticHouseholdsFood scraps, packaging, broken items
IndustrialFactories and industryChemicals, metals, manufacturing by-products
AgriculturalFarming activitiesAnimal manure, crop residues, empty pesticide and herbicide containers

Types of waste

  • E-waste: electronic waste such as old computers, mobile phones and televisions. It contains toxic materials like lead and mercury, which is why careless disposal is so damaging.
  • Food waste: edible food that gets thrown away, usually because too much was bought or because it spoiled.
  • Biohazardous waste: dangerous waste from hospitals and laboratories — medical equipment, needles, and blood or plasma samples.
Do not use “solid domestic waste” as a general word for rubbish. SDW is one category: the non-liquid waste that comes out of homes. If a question is about factory chemicals or farm manure, that is industrial or agricultural waste, and mixing the terms up costs marks in the first line of an answer.

What is actually in the bin

Solid domestic waste (SDW) is the non-liquid waste produced in homes. It typically contains a very wide variety of materials, and that mixture is the reason it is such a challenge to manage and recycle — a single bag may hold food, plastic, metal and textiles all stuck together.

What solid domestic waste is made of Estimated UK proportions, 2020 Garden waste 25% Kitchen waste 21% Other household items 11% Glass 9% E-waste and scrap metal 6% Furniture 6% Wood 6% Soil 4% Textiles 4% Plastic packaging 4% Disposable nappies 3% Paper 1% compostable recyclable mixed or difficult Garden and kitchen waste together are 46% — nearly half the bin
That top pair is the important number. It rots, so it makes methane in landfill, but it would compost easily. The biggest single win in domestic waste is separating it.

The materials that turn up most often in SDW are:

  • Paper — newspapers, magazines, packaging
  • Cardboard — boxes and containers
  • Glass — bottles and jars
  • Metal — aluminium cans and tins
  • Plastics — bottles, food containers, bags
  • Organic waste — food scraps, garden clippings and other biodegradable material
  • Packaging — plastic wrap, polystyrene foam, boxes
  • Construction debris — bricks and wood from repairs or renovations
  • Clothing — old or unwanted clothes and textiles

Why volume and composition differ

How much waste a society makes, and what is in it, changes over time and from place to place. Four groups of factors explain almost every difference you will be asked about.

Socio-economic factors

Wealthier societies usually generate more waste per person, because of:

  • Higher consumption levels
  • Single-use products
  • Excessive packaging
  • A culture of convenience
  • Fast fashion

High-income countries such as the United States generate more waste per person than lower-income countries such as India. But lower-income countries face a different problem: they may produce less waste, yet often have less capacity to manage it properly.

Two different problems, not one. A rich country’s issue is usually the volume of waste. A poorer country’s issue is usually the infrastructure to handle whatever waste exists. If a question asks you to compare waste in contrasting societies, that sentence is the backbone of your answer.

Political factors

Government policy changes how much waste is produced and how it is handled:

  • Recycling laws
  • Waste taxes
  • Bans on certain materials
  • Landfill regulations

Countries with strong waste management policies tend to have lower levels of unmanaged waste. The European Union’s ban on single-use plastics, for example, has reduced plastic waste across member countries.

Environmental factors

  • Environmental awareness reduces waste, through recycling and composting programmes.
  • Geographical location matters: popular tourist destinations produce far more waste during peak season.
  • Agricultural areas produce large amounts of crop waste after harvest.
  • Natural disasters generate waste suddenly — after a powerful hurricane, rebuilding creates huge volumes of construction and debris waste.

Technological factors

Technology cuts both ways, and this is a strong evaluation point.

Technology reduces wasteTechnology creates waste
Biodegradable plastics break down instead of persistingRapid upgrade cycles mean people replace working devices, creating e-waste
More efficient recycling methods recover more materialRenewable energy equipment eventually becomes waste too — old solar panels and turbine blades
Better design can extend product lifespansProducts designed for short-term use, such as disposable vapes, are waste by design
🧩

SPET: the four factor groups

Socio-economic, Political, Environmental, Technological. Run through the four whenever a question asks why waste differs between two places or two decades — you will rarely be short of points.

Worked examples

WE 1

Define solid domestic waste and outline its composition

Define solid domestic waste and outline why its composition makes it difficult to manage. (3 marks)

Point 1: the definition Solid domestic waste is the non-liquid waste produced in homes. Point 2: what is in it It contains a wide mixture of materials — garden and kitchen waste, glass, metals, plastics, textiles and furniture. Point 3: why that is a problem Because these materials are mixed together, they must be separated before they can be recycled or composted, which makes processing slow and expensive. The variety, not the volume, is what makes SDW hard to handle say “non-liquid” and “homes” — both words are doing work in the definition
WE 2

Explain differences in waste between two societies

Explain why waste production differs between a high-income and a low-income country. (4 marks)

Point 1: consumption Wealthier societies consume more, so they produce more waste per person, driven by single-use products, heavy packaging and fast fashion. Point 2: capacity Lower-income countries may produce less waste per person, but often have less capacity to manage it safely. Point 3: policy Strong recycling laws, waste taxes and landfill regulations reduce unmanaged waste, and these vary between countries. Point 4: technology Access to recycling technology and biodegradable materials differs, while rapid device turnover in richer countries adds e-waste. Different amounts, and different ability to deal with them avoid writing that poorer countries are simply “dirtier” — the issue is infrastructure and investment
WE 3

Discuss how technology affects waste production

Discuss the effect of technological development on the volume and composition of waste. (3 marks)

Point 1: it reduces waste Biodegradable plastics and more efficient recycling methods cut both the volume of waste and its persistence. Point 2: it increases waste Rapid upgrade cycles mean working devices are replaced, producing large volumes of e-waste containing lead and mercury. Point 3: composition changes too Waste streams now include solar panels, turbine blades and disposable electronics, which did not exist a generation ago. Technology changes what is in the bin as much as how much is in it “discuss” wants both directions; a one-sided answer will not reach the top mark

💡 Exam tips

  • Know both classifications: by source (domestic, industrial, agricultural) and by type (e-waste, food, biohazardous).
  • Define SDW precisely: non-liquid waste produced in homes.
  • Remember that garden and kitchen waste together make up about 46% of SDW — a useful figure for any question about composting.
  • Use the four factor groups as headings: socio-economic, political, environmental, technological.
  • For data questions, check whether the figure is total waste or waste per person.
  • Mention that e-waste contains lead and mercury whenever you explain why it is treated separately.

⚠ Common mix-ups

  • Using SDW to mean all waste. It is one category, separate from industrial and agricultural.
  • Confusing source with type. A phone from a house is domestic by source and e-waste by type.
  • Assuming low-income countries produce more waste. They usually produce less, but manage less of it safely.
  • Forgetting organic waste. It is the largest part of SDW, and the easiest to divert.
  • Treating technology as only a solution. It creates whole new waste streams.
  • Ignoring seasonality. Tourism and harvests make waste volumes swing through the year.
Up next: The Cost of Waste to People and Ecosystems. Now that you know what is in the bin, the next page follows it out of the door — into the air, the water, the soil, and into communities that never produced it in the first place.

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