Urban Waste and Pollution

Cities are concentrated producers of waste and pollution. A city of one million people generates approximately 2,000–3,000 tonnes of solid waste per day, along with millions of litres of wastewater and significant quantities of air pollutants. Managing this output sustainably is one of the defining challenges of contemporary urban environments.

Key Definition: The waste management hierarchy ranks waste management strategies from most to least environmentally desirable: Prevention > Reuse > Recycling > Recovery (energy) > Disposal (landfill). It was formalised in the EU Waste Framework Directive (2008) and underpins UK waste policy.

---

The Waste Management Hierarchy

graph TD
    A["Prevention<br>(Most preferred)<br>Reduce waste at source"] --> B["Reuse<br>Use items again for<br>same or different purpose"]
    B --> C["Recycling<br>Process waste into<br>new materials"]
    C --> D["Recovery<br>Energy from waste<br>Incineration with energy recovery"]
    D --> E["Disposal<br>(Least preferred)<br>Landfill"]

Prevention

Waste prevention is the most effective strategy but also the most difficult to implement. It requires changes in production processes, packaging design, consumer behaviour, and economic incentives:

• Plastic bag charges — England's 5p charge (2015, increased to 10p in 2021) reduced single-use plastic bag sales by major retailers by 95% from 7.6 billion to 0.4 billion per year
• Deposit Return Schemes (DRS) — Scotland has legislated for a DRS, with implementation aligned to a UK-wide scheme; countries with established DRS (e.g., Germany, Norway, Sweden) achieve return rates of 90–98% for bottles and cans
• Extended Producer Responsibility (EPR) — makes manufacturers responsible for the end-of-life management of their products, incentivising design for durability and recyclability

Reuse

Reuse extends the life of products without the energy costs of recycling:

• Charity shops — the UK has over 11,000 charity shops, the highest density in the world
• Repair cafés — community events where volunteers repair broken items; over 2,500 repair cafés worldwide (Repair Café Foundation, 2023)
• Refill and refurbishment schemes for electronics, furniture, and clothing

Recycling

UK recycling rates have improved significantly but have plateaued in recent years:

Year	England Recycling Rate
2000	~11%
2010	~39%
2015	~43%
2020	~44%
2023	~44%
Target	65% by 2035 (Environment Act 2021)

Recycling faces several challenges:

• Contamination — incorrectly sorted waste reduces the quality and value of recyclable materials
• Export dependency — following China's National Sword policy (2018), which banned imports of most recyclable waste, the UK lost a major outlet for recycled materials
• Material complexity — multi-material packaging (e.g., Tetrapak cartons, flexible plastics) is difficult and expensive to recycle
• Municipal variation — recycling collection systems vary enormously between local authorities, confusing householders

Energy Recovery

Energy from Waste (EfW) plants incinerate non-recyclable waste to generate electricity and/or heat. The UK has approximately 50 EfW facilities:

Facility	Location	Capacity
Runcorn EfW	Cheshire	850,000 tonnes/year
Ferrybridge MFE	Yorkshire	570,000 tonnes/year
SELCHP	Lewisham, London	420,000 tonnes/year
Edmonton EcoPark (under construction)	Enfield, London	700,000 tonnes/year

Evaluation of EfW:

• Diverts waste from landfill and generates energy (a modern EfW plant generates approximately 550–700 kWh per tonne of waste)
• But produces CO₂ emissions (though less than landfill over 100-year timescale when methane is considered)
• Can discourage waste prevention and recycling by creating demand for waste feedstock — the "lock-in" effect
• Air quality concerns — modern plants have stringent emission controls but face public opposition (NIMBYism)

Landfill

Landfill is the least desirable option but remains the destination for approximately 24% of UK municipal waste (2020). Landfill problems include:

• Methane emissions — decomposing organic waste produces methane, a greenhouse gas with 80 times the warming potential of CO₂ over 20 years
• Leachate — contaminated liquid that percolates through waste and can pollute groundwater and watercourses
• Land take — landfill sites occupy valuable land, often in areas that communities depend on
• Odour, vermin, and visual impact — landfill sites are a source of local environmental nuisance

The UK Landfill Tax (introduced 1996, currently £103.70/tonne in 2024) has been the single most effective policy in reducing landfill use, by making disposal significantly more expensive than alternatives.

Exam Tip: When discussing waste management, always evaluate strategies against the hierarchy. The strongest answers will argue that policy should prioritise prevention and reuse but acknowledge the practical and political difficulties of changing consumption patterns.

---

The Circular Economy

The circular economy concept challenges the traditional linear economy model of "take-make-dispose" by designing waste out of the system entirely: