Topic 10: Solid Wastes Flashcards
Name 3 sources of solid wastes
Mining and construction
Domestic and commercial/municipal
Industrial
Mining and construction waste
Produce large amounts-most are non-hazardous but some can be which cause issues
Mine overburden heaps: usually non toxic
Mine spoil heaps: have toxic chemicals
Demolition waste, might contain hazardous material e.g. asbestos
The main categories of domestic and commercial waste
Packaging and containers
Paper
Domestic appliances
Organic material e.g. food and garden waste
Clothing/textiles
Problems with waste management of domestic sources
Large quantities are produced but have to be collected in small quantities from each household which is expensive and labour intensive
The mixture of waste varies throughout the year e.g. more garden waste in the summer
Different types of waste are mixed together
Why so the properties of solid waste matter?
They influence the disposal method
Name 5 properties of solid waste
Degradability
Conditions that affect degradability
Flammability
Release of radioactivity
Toxicity
How does affluence impact waste?
It has an effect on the amount of waste generated
Why does affluence affect the amount of waste generated?
More affluence means people are more likely to puurchase more goods and more disposable items. They are also more likely to throw things away instead of repairing them
This then increases waste from manufacture of goods and mineral extraction too
How can manufacturing and retail industries increase waste?
Certain sale strategies can increase waste:
Built in obsolescence
Disposable products
Overpackaging
What is built in obsolescence?
When items are purposely made with a short lifespan- they aren’t durable
Fast fashion, encourages clothing to be discarded
Customers are encouraged to upgrade to the latest model
What are disposable products?
Items intended to have a limited usable life so need to be replaced sooner
E.g. razors,lighters, ballpoint pens
Overpackaging
Done to make items more attractive
But the unnecessary packaging is likely to be thrown away
How are solid wastes disposed, how may this be an issue?
Large amounts are deliberately or accidentally dumped in the environment
Can harm wildlife that can swallow or get caught in it
Plastic wastes can degrade into small particles which choke marine life or release chemicals that cause endocrine disruption
What factors affect the method chosen for waste disposal?
Population density, mass of waste per capita, waste properties,land availability, recycling technology,degree of environmental awareness,legislation,household income, waste processing cots
Why might population density affect waste disposal?
Collection costs might be higher if there are fewer people further apart
What is landfill?
Simplest disposal option
Require little/no treatment of waste
Early landfill sites were poorly managed
Features of good landfill site management
Separation of types of waste,recording their location
Polymer liners
Perimeter fence
Covering waste with soil
Collection and treatment of leachate and methane
Impermeable cap
Deodorising spray
Dispersal of flammable materials
Why may polymer liners be a feature of a well-managed landfill site?
To prevent the escape of leachate fluid
Why is a perimeter fence a feature of a well managed landfill site?
It will trap litter blown by the wind
What are the disadvantages of landfill?
Potential resource value is lost
Large amounts of land used-habitats/farmland lost
Organic matter decays anaerobically=methane
Toxic leachate may leak
Contamination may prevent later development of these sights
Transporting waste to them, can cause noise and congestion
Spoil heaps
Industrial spoils usually have large quantities of non-toxic solids, the main issue with them is quantity
They can also produce polluting leachate fluids
How are spoil heaps produced?
Mining and quarrying
Coal fired power stations/incinerators produce ash
Iron blast furnaces produce slag
Why do spoil heaps need to be managed?
To minimise environmental problems
Make site easier to reuse after sight closure
What problems need to be solved for successful management of spoil heaps?
Stability,drainage,lack of nutrients,PH,contamination,topography,toxic leachates,heavy metals,flammable wastes
Why is the stability of spoil heaps an issue and how ca it be reduced?
Landslides are a danger
Reduce surface erosion by establishing vegetation-the roots hod the spoil together
Or compaction can be used
Why does drainage need to be resolved for spoil heaps?
Especially on tall spoil heaps/hillsides to reduce risk of landslides after heavy rain
Issue of lack of nutrients with spoil heaps and how it can be resolved
Some contain low levels of plant nutrients but sewage sludge,topsoil and fertilisers may be used to improve nutrient content and increase plant growth
How can the issue of PH with spoil heaps be resolved?
Addition of lime-reduce acidity
Old steelworks can leave alkaline wastes which can be valuable to. Uncommon plants e.g.cowslips
Give 2 ways contamination from spoil heaps can be resolved
Phytoremediation
Bioremediation
Phytoremediation
Where plants are used to absorb and store pollutants like heavy metals
Bioremediation
Can be used to treat petrochemical waste e.g. oil
Certain bacteria will digest oil in the right conditions
How can the issues of topography with spoil heaps be resolved?
They can be unattractive, landscaping can be used to shape it but it could require more land
How is the problem of toxic leachates with spoil heaps resolved?
They can be collected and treated so they dont enter water sources
Deep soil layers in restoration stop plant roots coming into contact with toxic materials
Roots could bring them to the surface and cause wider dispersal
What is the problem with heavy metals in spoil heaps?
They are problematic when they are mobile in the environment
They can be inhaled or ingested
How can the problems with heavy metals in spoil heaps be resolved?
Prevent disposing them in solid forms in alkaline conditions
They should be convered so there are no airborne dust particles
What is the problem with flammable wastes in spoil heaps?
Coil/shale spoil can spontaneously combust because of the high proportions of hydrocarbons
How can the issues with flammable wastes in spoil heaps be reduced?
Layers of fine grained materials which will reduce air flow
What is incineration?
It involves the destruction of wasted by high temperature oxidation
Advantages of incineration
Less ash volume than original waste
Heat produced can be used for electricity generation/district heating
No complicated management/sorting
Flammable materials can be burned in purpose built power stations
Fuels can be created
What fuels can be created in incineration?
RDF- refuse derived fuel: pellets of compacted municipal waste
TDF- tyre derived fuel: made from shredded tires
Disadvantages of incineration
Resource value lost
Toxic dioxins are produced
The fuel to maintain the combustion of wet/non flammable sis expensive
Features of good domestic waste incinerators
Recyclables/high water content wastes are removed before incineration
Combustion temp is kept high and waste gases are cooled rapidly to reduce dioxin production
Heat produced is harnessed
Atmospheric pollution is controlled
2 examples of specialist wastes
Asbestos
Cyanide
How is asbestos dangerous?
If it disintegrates- the airborne fibres are irritants
Leads to asbestosis-scar tissue and alveoli thicken-breathing slowed
Cause a specific cancer- mesothelioma
Mesothelioma
Cancer o the tissues that cover many internal organs
Can take decades to develop
80% of cases are caused by asbestos
How is asbestos used?
To strengthen cement root panels and in textured ceiling coverings
It isnt dangerous as long as it is encapsulated and remains intact
How is asbestos waste controlled?
Requires special handling
Double wrapped in heavy duty polythene bags in special landfill sites where waste contents are recorded
When is cyanide used?
Manufacture of paper,textiles and plastic
Salts of cyanide are used in electroplating,metal cleaning and gold extraction
Problems with cyanide
Cyanide compounds can be very toxic
They are enzyme inhibitors
Can be inhaled or ingested
How is cyanide waste controlled?
Incineration is the safest disposal method
Carbon and nitrogen are seperated and oxidised
CO2 and NOx are produced but are a smaller pollution problem
What is encapsulation used for?
Hazardous waste containing heavy metals
E.g. arsenic,mercury,Mickey, chromium residues and intermediate radioactive waste
How does encapsulation work?
The hazardous wastes are mixed with a cement slurry which is poured into containers made of impermeable and unreactive metals
The solid cement encapsulated the waste so it is immobilised
What is vitrification used for?
The storage of high level radioactive waste, extracted from used nuclear fuel
Process of vitrification
Powdered radioactive waste is mixed with molten glass
Then poured into stainless steel containers which are then sealed
Glass solidifies with waste encapsulated-would remain even if glass was shattered
