Solid Waste

Question 1

Sources of solid waste

Answer 1

Mining and construction waste, Domestic and commercial waste, Industrial waste, Agricultural waste

Question 2

Properties of solid waste

Answer 2

degradable, flammable, toxic, radioactive

Question 3

Conditions that affect degradation of waste

Answer 3

Temperature, oxygen availability, pH, presence of bacteria

Question 4

Affluence is positively correlated with waste production because:

Answer 4

1 more consumer goods purchased
2 more trivia purchased
3 more disposable items purchased
4 more items are thrown away rather than repaired

Question 5

Manufacturing and retail increase sales and waste through:

Answer 5

1 inbuilt obsolescence
2 disposable products
3 over-packaging

Question 6

Factors affecting waste disposal methods

Answer 6

population density, mass of waste per capita, properties of the waste, land/space availability, availability of technology, degree of environmental awareness, legislation, household income, labour and machinery costs.

Question 7

Advantages of landfill

Answer 7

low level of technology required, energy production - landfill gas, more affordable than incineration

Question 8

Disadvantages of landfill

Answer 8

Resource value is lost, large area of land required, wildlife habitat and agricultural land lost, organic matter decays anaerobically and produces methane, toxic leachate produced, contamination of land restricting later development, transport and infrastructure generate noise, dust, energy use.

Question 9

Good landfill site management

Answer 9

Records of waste type and location, polymer liner to prevent leachate migration, perimeter fence to trap wind blown litter, covering with soil to prevent pests, collection of methane and used as a fuel, collection and treatment of leachate, impermeable cap, deodorising sprays, dispersal of flammable materials, separation of reactive chemicals, traffic management

Question 10

Leachate

Answer 10

Drainage water that carries other substances, either in solution or as suspended solids.

Question 11

Incineration (energy from waste)

Answer 11

The breakdown of a waste by burning it.

Question 12

Advantages of incineration

Answer 12

Volume and mass reduction, heat generated can be used for space heating or electricity generation, no sorting required

Question 13

Disadvantages of incineration

Answer 13

Resource value is lost, Dioxins produce from the reaction of organic waste and chlorine, fuel required to maintain combustion, some separation of waste required, effluent gasses require treatment

Question 14

Features of a good incinerator

Answer 14

recyclable waste removed before incineration, wet waste removed before incineration, combustion temperature high and effluent gases cooled to prevent dioxin production, Heat is harnessed for use, SO2 NOx HCL CO PM10 controlled, Scrubbers used to remove hydrogen chloride or crushed limestone to neutralise hydrochloric acid, magnets used to remove metals before and after combustion.

Question 15

RDF

Answer 15

refuse derived fuel - glass and metal removed, waste is shredded, dried and baled/pelleted, later burned to produce energy

Question 16

TDF

Answer 16

tyre derived fuel - shredded scrap tyres burned for heating kilns or for energy production

Question 17

Spoil heap

Answer 17

A pile of low value waste material removed for mined or excavation

Question 18

Dangers of spoil heaps

Answer 18

Instability - risk of landslide, acidic leachate which may contain heavy metals, some spoil is flammable

Question 19

Spoil heap stabilisation

Answer 19

Establish vegetation for root binding, compaction, drainage to remove additional water mass after rainfall

Question 20

Increasing spoil heap nutrients

Answer 20

addition of topsoil, sewage sludge or artificial fertilisers

Question 21

Raising spoil heap pH

Answer 21

add lime to sulphide ores

Question 22

Reducing spoil heap contamination

Answer 22

Phytoremediation, growing plants that absorb the toxic materials. Bacteria can be used to digest/remove oil

Question 23

Improving spoil heap topography

Answer 23

landscaping to remove steep slopes and angular shapes however more land will be required.

Question 24

Dealing with spoil heap leachate

Answer 24

leachate collected and treated, deep layers of soil to stop plant roots reached toxic materials

Question 25

Dealing with spoil heap heavy metals

Answer 25

raising pH to reduce solubility of metals

Question 26

Reducing the flammability of spoil heaps

Answer 26

Coal or shale spoil is flammable, introduce layers of fine grained material to reduce air flow and reduce spontaneous combustion

Question 27

Encapsulation

Answer 27

a method of dealing with hazardous waste whereby the material is mixed with concrete and poured into a container so that the waste is immobilised.

Question 28

Vitrification

Answer 28

a specialised encapsulation technique used for high level radioactive waste, powdered radioactive waste is mixed with molten glass and poured into stainless steel containers, the containers are placed in cylindrical passage in concrete which are ventilated. Even if the glass is shattered the powdered waste will remain encapsulated in glass

Question 29

Asbestos disposal

Answer 29

Asbestos fibres cause asbestosis and mesothelioma (a type of lung cancer), intact and enclosed asbestos is safe, degrading asbestos and loose fibres are dangerous. Asbestos requires double wrapping in strong polythene and disposing in a specialised landfill where its location will be recorded.

Question 30

Cyanide disposal

Answer 30

Cyanide compounds are enzyme inhibitors, they are used in the manufacture of paper, textiles and textiles and in electroplating, metal cleaning and gold extraction. Incineration is the safest disposal method whereby the carbon and nitrogen atoms in the compound are separated.