Solid waste disposal

Question 1

What does managing a dumpsite for rehabilitation involve?

Answer 1

• Closing the site: no longer causes degradation of the environment
• Landfill mining : excavating and making use of stabilised waste so landfill can be reused

Question 2

What aren the different ways of closing dumpsites?

Answer 2

• The ‘Dry tomb’ systm: allow as little infiltration of water into the wast layers as possible
• The bioreactor system

Question 3

what is necessary for ‘dry tomb’ system to close a dump sitee?

Answer 3

• Surface drainage system: to collect and remove all surface runoff from the landfill site
• Clay or plastic linings: placed at the bottom and the sides of the landfill to prevent leachates from seeping into the surrounding environment, polluting the soil as well as surface and groundwater.
• A leachate collection and treatment system : The leachate must drain into reservoirs or lagoons where it can be treated. some landfills re-circulate the leachate back into the waste to speed up decomposition
• cover of clay-rich soil: must be laid over the waste after it has been compacted. ensure surface drainage and prevent water infiltrating the waste, allow for growth of vegetation

Question 4

What is the bioreactor system?

Answer 4

A sustainable sanitary landfill system , which fluids or gases are circulated through the waste in a controlled manner

Question 5

What is leachate?

Answer 5

runoff which contains both dissolved and suspended material

Question 6

What is bioreactor?

Answer 6

An apparatus in which a biological reaction or process is carried out.

Question 7

Why use bioreactors?

Answer 7

• speed up degradation by increasing the action of decomposer micro-organisms
• cost effective and sustainable approach to current waste disposal problems

Question 8

What accelerates the process of closing a dumpsite?

Answer 8

Moisture of wast which accelerates decompoisiton

Question 9

what is a disadvantage of using a bioreactor?

Answer 9

produces more methane and gases than in traditional landfills

Question 10

what is the use of landfill mining?

Answer 10

involves excavating and making use of wastes

Question 11

why is landfill mining important for dumpsite rehabilitation?

Answer 11

waste is sorted so that it can either be re-used, recycled or burnt.
make space available for refilling site and it reduces the detrimental effect on the environment.

Question 12

What can the recovered material be re-used for?

Answer 12

• cover material for active landfill sites
• compost as fertiliser for agriculture
• re-sale of appropriate items
• recycling of materials, e.g cans, paper, glass.

Question 13

What is a new approach to sustainable management of management of dumpsites?

Answer 13

• rehabilitation by:
• closing( dry tomb or bioreactor)
• landfill mining
• reduction of waste and recycling to conserve the remaining space in currently used landfills.

Question 14

What is rehabilitation of dumpsites?

Answer 14

Waste is treated in such a way that it is not damage the environment