Six methods, none of them perfect. The exam almost never asks “which is best” — it asks you to weigh a method against its impact on ecosystems and on the people who live nearby. Learn one clear advantage and one clear disadvantage for each and you can answer anything here.
📘 What you need to know
The six methods: landfill, incineration, waste-to-energy, exporting, recycling and composting.
Landfill is cheap and flexible but generates methane and risks groundwater contamination through leachate.
Incineration cuts waste volume sharply but causes air pollution and leaves toxic ash.
Waste-to-energy (WtE) recovers usable energy, but it does not reduce how much waste we make.
Exporting shifts the problem rather than solving it, and raises environmental injustice.
Recycling conserves resources but needs energy, facilities and clean, uncontaminated material.
Composting handles the biggest slice of household waste cheaply, but only works for organic material.
1. Landfill sites
Landfills bury waste in designated areas in large holes dug into the ground. A modern engineered landfill is far more than a hole: it has a sealed liner underneath, a system for collecting the liquid that drains out, and pipes to capture the gas produced as the waste rots.
An open dump has none of this. The difference between a dump and an engineered landfill is the liner, the leachate pipe and the gas capture.
LANDFILL — ADVANTAGES
Centralised: one location manages large volumes of waste
Flexible: handles a wide range of materials, including non-recyclables
Low operating cost compared with other disposal methods
Engineered protection: liners and leachate collection reduce environmental impact
Gas capture: some sites collect methane and use it as an energy source
LANDFILL — DISADVANTAGES
Methane generation — a potent greenhouse gas
Land hungry: needs significant space, which is hard to find near cities
Contamination risk: leachate can pollute groundwater and soil
Long-term monitoring required long after the site closes
Environmental injustice: noise and smell usually fall on less affluent urban outskirts
2. Incineration
Incineration burns waste at high temperatures to reduce its volume. It is not the same thing as waste-to-energy: pure incineration destroys the waste without necessarily recovering anything useful from it.
INCINERATION — ADVANTAGES
Reduces waste volume drastically
Less reliance on landfills, so less land is needed
Handles hazardous waste that cannot safely be buried
INCINERATION — DISADVANTAGES
Air pollution: emits harmful gases and pollutants, including greenhouse gases
High operating costs: expensive technology and maintenance
Ash disposal: produces toxic ash that itself needs careful disposal
Public opposition over health and environmental concerns
Notice the trap. Incineration reduces volume, not mass of pollutants. What went in as solid waste largely leaves as gases plus a smaller amount of concentrated toxic ash. It is a transformation, not a disappearance.
3. Waste-to-energy (WtE)
Waste-to-energy plants, also called energy-from-waste (EfW), burn waste to generate electricity or heat. The idea is to get something back from material that would otherwise just be destroyed.
Compare this with the nuclear station diagram in 7.2 — from the furnace onwards it is the same machinery. Only the fuel differs.
WtE — ADVANTAGES
Energy recovery: turns waste into usable energy, reducing fossil fuel use
Reduces landfill use
Cuts waste volume significantly
WtE — DISADVANTAGES
Pollution risk: harmful emissions and greenhouse gases unless carefully controlled
High capital cost to build, run and maintain
Limited by composition: not all waste burns efficiently
Not a real solution: it still relies on waste being generated rather than reducing it
🤔 Why waste-to-energy is controversial even though it sounds sensible
A WtE plant is expensive and lasts for decades, so the operator needs a guaranteed supply of waste for years to pay it off. That creates a quiet incentive to keep waste volumes high, which sits directly against reduction and recycling targets. Some cities have found themselves importing rubbish to keep their incinerators busy. So the objection is not really about the technology — it is that building one locks a city into a future where waste keeps arriving. That is a strong evaluative point.
4. Exporting waste
Exporting means sending waste to other countries for treatment, recycling or disposal.
EXPORTING — ADVANTAGES
Offloads responsibility for countries with waste management difficulties
Reduces domestic pressure on local waste systems
Access to advanced facilities that the exporting country may not have
Economic benefit: often cheaper than processing at home
EXPORTING — DISADVANTAGES
Environmental injustice: harm falls on low-income receiving countries
Transport emissions: shipping waste long distances adds carbon
Legal risks and disputes between exporting and importing nations
Solves nothing long term: the root cause is still excessive waste generation
5. Recycling
Recycling converts waste materials into new, usable products.
RECYCLING — ADVANTAGES
Resource conservation: less need for new extraction, which is damaging and polluting
Energy savings: usually uses less energy than making materials from scratch
Economic: can be cheaper than other disposal routes
Keeps materials out of landfill and incinerators
RECYCLING — DISADVANTAGES
Energy in processing: collecting, sorting and reprocessing is energy-intensive
Limited facilities: access varies hugely between countries and regions
Contamination: dirty recyclables reduce the efficiency of the whole process
Limited market: not everything is recyclable, and demand for recycled material can be weak
The contamination point is the one that surprises students. One greasy pizza box in a paper bale can downgrade the whole load. That is why “wash it and separate it” campaigns exist, and it is a neat link into behaviour change on the next page.
6. Composting
Composting breaks down organic waste into nutrient-rich soil. Given that organic material is the single largest component of household waste in many countries, this is a bigger lever than its low-tech feel suggests.
COMPOSTING — ADVANTAGES
Environmentally friendly: makes natural fertiliser, reducing the need for chemical ones
Reduces landfill waste and therefore lowers methane emissions
Enriches soil and can improve crop growth
Low cost: can be done at home or at community scale
COMPOSTING — DISADVANTAGES
Organic waste only: cannot handle plastics, glass or metals
Space and time: needs room for the piles and weeks to break down
Odour if it is not managed properly
Comparing the six
Method
Main strength
Main weakness
Who it affects most
Landfill
Cheap and takes anything
Methane and leachate
Nearby, often poorer, communities
Incineration
Huge volume reduction
Air pollution and toxic ash
Local air quality and public health
Waste-to-energy
Recovers usable energy
Encourages continued waste generation
Long-term city waste policy
Exporting
Immediate relief at home
Environmental injustice abroad
Low-income receiving countries
Recycling
Conserves raw materials
Contamination and weak markets
Households and sorting workers
Composting
Cuts the largest waste stream cheaply
Only works on organic material
Households and local soil quality
EXAM-STYLE
Outline two environmental disadvantages of landfill sites. [2]
Disadvantage 1
Decomposing organic waste generates methane, a potent greenhouse gas that contributes to climate change.
Disadvantage 2
Leachate can escape and contaminate groundwater and soil, harming ecosystems and drinking water supplies.
2 marks: methane, leachate contamination“Environmental” rules out the injustice and property value points here. Read the adjective in the question.
EXAM-STYLE
Evaluate the use of waste-to-energy plants as a waste disposal method. [6]
In favour
WtE recovers usable energy from material that would otherwise be buried, which reduces reliance on fossil fuels. It sharply reduces waste volume and cuts the amount going to landfill, so it lowers methane emissions from landfill sites too.
Against
Burning waste releases harmful emissions and greenhouse gases unless the flue gases are carefully cleaned. Plants are expensive to build, operate and maintain. Not all waste burns efficiently, and toxic ash still needs disposal.
The deeper objection
WtE does not reduce waste generation. Because plants are costly and long-lived, they need a steady waste supply, which can work against reduction and recycling targets.
Judgement
WtE is better than landfill for waste that cannot be recycled or composted, but it should sit low in the hierarchy, below reduction, reuse and recycling, and only with strict emissions control.
6 marks: both sides with detail, plus a justified position
💡 Exam tip
Learn one advantage and one disadvantage per method first, then add detail. Coverage beats depth here.
Use the technical words: leachate, methane, flue gases, toxic ash, contamination.
Incineration and WtE are different. WtE recovers energy; plain incineration may not.
For any method, be ready to say how it affects ecosystems and how it affects communities. The syllabus asks for both.
Mention environmental injustice for landfill siting and for exporting. It applies to both.
In evaluations, rank the method against the waste hierarchy rather than judging it in isolation.
⚠ Common mix-up
“Incineration gets rid of waste.” It converts it into gases and toxic ash. Nothing vanishes.
Landfill confused with an open dump. Engineered landfills have liners, leachate collection and gas capture; dumps do not.
Recycling assumed to be free of impact. Sorting and reprocessing use energy, and contaminated loads get rejected.
Composting described as a fix for all waste. It only handles biodegradable material.
Exporting counted as a solution. It moves the problem and creates injustice; it does not reduce waste.
Listing advantages without any judgement in an evaluate question. State a position at the end.
Up next: Managing and Reducing Waste — the hierarchy, the circular economy, and the strategies that stop waste being made in the first place.
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