Contemporary Urban Enviroments - Section 6 Urban Waste Flashcards
What are the 3 primary sources of waste in urban areas?
1) industrial waste - waste produced in manufacturing process or from industrial activity
2) commercial waste - any waste produced by businesses eg) shops, restaurants offices
3) personal waste - any waste produced in private homes
What are the largest components of waste globally?
Organic material (46%)
Paper (17%)
Plastic (10%)
Glass (5%)
What is municipal solid waste (MSW)?
Refuse/rubbish
The composition of MSW changes between countries and varies overtime
Nowadays, it predominantly includes, food waste, market waste, street waste, product packaging, other miscellaneous waste from residential, commercial, institutional sources
What is a waste stream?
The flow of waste from its source/origin through to its eventual disposal
Some products (eg paper, glass) can be recycled
Others need to be broken down into their component parts - each part disposed of separately
e.g. by recycling, sending to landfill, processing to extract useful chemicals or metals, or treating to reduce risk.
What factors do waste streams and components of waste depend on?
Economic characteristics
Lifestyles
Attitudes
What are economic characteristics of waste?
As people get richer they tend to consume more goods. So developed countries produce more waste (2.1kg per person per day) than developing countries (0.6kg per person per day).
The components of waste also vary depending on the level of development of the country.
Developed countries – paper (31%), organics material (28%) and plastic (11%).
Developing countries – organics material (64%) plastic (8%), paper (5%)
Waste generation tends to be greater where disposable incomes and living standards are higher
In HICs disposal of waste is increasingly regulated and managed. In most LICs and NEEs improper dumping of MSW without treatment is particularly common.
What environmental issues does improper dumping of MSW create?
Loss of recyclable resources
Contamination of land and water bodies
Air pollution due to emissions from burning and release of methane from decomposition
Multiple risks to human health
How do lifestyles affect waste?
Amount and type of waste produced varies depending on whether people live in the city or country.
People in urban areas produce more waste than those in rural areas.
People in rural areas produce more organic waste (e.g. food) and people in urban areas produce
more manufactured waste (e.g. plastic, glass).
Diet is likely to affect waste components and streams.
For example:
Producing processed food creates waste and finished products tend to come in a lot of
packaging.
Fruit and vegetables tend to produce more compostable waste (e.g. vegetable peelings) and less
packaging
How do attitudes affect waste?
Many developed countries have a throw-away culture. For example:
Electronics are replaced regularly
Clothing may be bought, worn a few times then thrown away.
This results in high levels of waste, much of which cannot be recycled or has a long and complex waste stream.
People have different attitudes towards the environment. People who are concerned about the environmental impacts of excess waste are more likely to reuse or recycle waste.
What factors does waste composition depend on?
Cultural norms
Geographical location
Energy sources
Climate
What are the impacts of increasing waste generation?
Costs of collecting and treating waste are high
Water, ground and air pollution - waste is a large source of methane, a powerful greenhouse gas
Health problems - from untreated or uncollected waste
Quantity - many city authorities are struggling to collect increasing quantities of urban waste.
Cities running out of landfill space
Waste management generally follows an accepted hierarchy
What are the approaches to waste management in order from least to most preferred?
Controlled dump
Incineration
Landfill
Recover (digestion, composting)
Recycle
Reuse
Reduce
Methods of waste management and disposal:
What is unregulated waste disposal and its problems?
Waste is dumped in places that aren’t official disposal sites (it is not controlled or supervised by regulation of law).
Problems:
Waste not properly disposed can damage ecosystems
Animals and birds can be harmed if they swallow or get tangled in waste
Contamination of groundwater and surface water by leachate.
Air pollution from burning waste
Can be a breeding ground for insects, vermin and scavenging animals, and so pass on air-borne and water-borne diseases.
Methods of waste management and disposal:
What is recycling and advantages/ disadvantages?
Waste is reprocessed into new products, e.g. plastic bottles can be turned into fleece jumpers.
Means less waste disposed of
Returning materials to the economy - reduces demand for raw materials, which decreases the environmental impacts of resource extraction e.g. deforestation.
Producing recycled products generally uses less energy than making them from scratch, so less greenhouse gases, such as CO2, are emitted.
Requires separate collections and the construction of new facilities to process waste – these contribute to greenhouse gas emissions and air pollution.
Methods of waste management and disposal:
What is incineration and advantages/disadvantages?
This is when waste is burnt - common in poorer countries
Greenhouse gases are released into the atmosphere through combustion.
Causes forms of air pollution
Can release toxic chemicals into soil/water
Reduces amount of waste going to landfill.
Waste that is burnt can be used to generate electricity – this is called energy recovery.
Can reduce the volume of waste by up to 90%.
