Solid Waste Management

Question 1

Define waste

Define Hazardous waste

Answer 1

all unused, unwanted and discarded materials including solids, liquids and gases

Hazardous waste= defined as hazardous if its flammable, toxic or carcinogenic

Question 2

MSW

BMW

Answer 2

MSW= Municipal Solid Wastes- non-hazardous, mainly biodegradable

BMW= Biodegradable Municipal Wastes

Question 3

Waste disposal options

Answer 3

-Landfill pre-treatment

-Recycling

-Landfill of untreated waste

Question 4

Types of landfill and characteristics

Answer 4

Total Containment- impermeable strata
o Concentrate and contain

Slow Dispersal- permeable strata
o Dilute and disperse
o If this is unengineered can lead to ground contamination

Question 5

EU Landfill directive

Answer 5

• Prevention
• Preparing for Re-use
• Recycling
• Other Recovery
• Disposal

Question 6

What controls the environmental risks from landfill

Answer 6

o Waste Type
o Landfill Design
o Environmental Factors
o Management Factors

Question 7

What are the environmental risk pathways from landfills

Answer 7

• Gases may volatilize and enter atmosphere- compounds which evaporate readily, secondary pollutants from reactions in atmosphere
• Heavy metals retained in soil
• Soluble and toxic substances pass through to groundwater system
• Surface runoff picks up leachate and transports to surface water network
• Some crops may selectively take up heavy metals- passed along food chain- biomagnification
• Transport of paper and plastic by the wind

Question 8

Factors influencing gas and leachate generation in landfills

Answer 8

• Refuse composition density, particle size
• Temperature, pH
• Oxygen, hydrogen, sulphate, toxics, metals
• Moisture Content
• Nutrients, Microbes

Question 9

Any solid fuel contains 2 combustible constituents:

Answer 9

• Volatile matter- released as mixture of vapours
• Solids- char (burns to produce CO2), with an inert matter (clinker/Slag)

Question 10

Advantages of AD for MSW

Answer 10

• Gas yields much higher and digestion complete in a few weeks
• Feedstock= organic fraction of MSW, diluted into a slurry
• Can be closer to urban areas, reducing transport cost
• Requires less land