Landfills

Question 1

Explain why landfills may emit material

Answer 1

• Concentration gradients between the landfill and its surroundings.
• Reactivity of the waste - chemical energy within the material, which can power
  reactions and phase changes.
• Fluxes of liquid or gases in the environment that may pass the landfill or part of it.
• Gradients of potential energy can cause slides.

Question 2

What is the alternative to landfilling (in terms of waste disposal)? What does
that mean for the waste hierarchy and the importance of landfills?

Answer 2

Dispersion.
Landfills are the fundament of the waste hierarchy. All steps (apart from reuse) cause
residuals that either have to be landfilled or are spread to the environment as diffuse
emissions.

Question 3

Name two realistic drivers for landfill mining and explain them briefly.

Answer 3

• Recover landfill space to landfill more (capacity extension).
• Reclamation of the land for other use
• Remove hazardous waste/an old landfill from an unsuitable place
• Temporary waste removal to upgrade landfill infrastructure or repair e g a leaking
  bottom liner

Question 4

Which purposes do landfills serve in waste management?

Answer 4

To store material temporarily or permanent
- To be the back-up option to other facilities
- Location for various sorting, recycling and treatment activities

Question 5

How may landfills affect the global warming?

Answer 5

Landfills may increase or decrease global warming in different ways, such as:
- Methane emissions may increase it
- Methane oxidation occurring in the top layer may decrease global warming
- Landfills are carbon sinks since some of the landfilled carbon stays in the landfill
- Landfilling is a waste disposal option with fairly low energy demand

Question 6

The waste hierarchy aims at reducing the amount of wastes being landfilled.
Name and explain three advantages and disadvantages with this strategy.

Answer 6

Advantages:
* Better environmental control: decreasing of contaminants discharge in the surrounding
(air, ground and water);
* Fewer and larger landfills that can be operated more efficiently and at high standards
(BAT);
* Increased recycling and reuse of products and materials, nutrients or the energy content
of waste;
* Development of knowledge about waste and treatment opportunities; improvement of
treatment processes, recycling…
There are also disadvantages with this strategy:
* higher treatment costs because it’s more expensive to treat each kind of waste separately;
* more diffusion (emissions) from more treatment;
* risk of accumulation of contaminants within the society/circular economy due to
increased reuse of waste
* more transport (waste to and from treatment facilities, to adapted landfills, …);
* more complicated administration with specific protocols for disposal of waste at different
landfills, control (the identity of waste producer, the source process, the waste
composition…must be noted), and so on.