Waste Management Flashcards
What is waste?
Waste is any material people at home or
work discard because they no longer need it.
How do we dispose of waste?
Landfill - 54%
Recycled, Composted or Incinerated - 46%
What is a landfill site?
A landfill site is a licensed facility where waste is deposited for permanent disposal. Modern landfills sites are designed to confine the waste to prevent it from causing environmental or health problems.
What type of hazards are created by landfill sites?
Groundwater /Aquifer Contamination
Production of Landfill Gas (methane)
Landfill fires
Offensive odours
Litter
Pests (Rats, seagulls and flies)
Increased traffic for duration of infilling
Long term subsidence after closure
What is Leachate?
Leachate is formed when water percolates
through rotting, solid waste. Leachate can be highly acidic and so toxic to many animals and plants.
What gases are most commonly created in landfill sites?
The gas from a typical landfill site
consists mostly of methane (CH4) and
carbon dioxide (CO2).
What problems are modern landfills designed to
minimise?
Location
Landfill Liner
Compaction of waste
Daily Cover
Landfill Cap
Leachate Management System
Landfill Gas Management System
Where can’t a landfill site be located?
A geologically stable area
On a major aquifer
In a tectonically vulnerable area
What can landfill liners be made of?
Compacted Clay
Bentonite (clay mineral) Enhanced Sand
Geo-membrane
Geotextile Protector
Dense Asphaltic Concrete (DAC)
Combination of the above
How is waste deposited in a landfill site?
Waste is placed in layers approximately 3 m
thick and compacted. At the end of each working day approximately 0.3 m of clay or sand material is placed on top of the waste to:
- minimise the infiltration of rainwater
- isolate the waste from birds and vermin
- reduce odours
What is a leachate management system?
Leachate management systems are installed to:
- prevent the accumulation of leachate in the base
of the landfill
- collect, re-circulate and dispose of leachate during operations and after closure
They comprise of:
- leachate drainage blanket at base of landfill
- pipes along base and sidewalls of landfill
- wells to monitor and extract the leachate
What is a landfill gas management system?
Landfill gas management systems are installed to
prevent the build up of gases within the landfill and
to prevent migration of landfill gas through the
underlying strata.
There are 2 ways landfill gas can be managed:
- Passive management systems comprise of wells with perforated tops to allow the gas to vent naturally into the atmosphere
- Active management systems involve the active extraction of the gas. The extracted gas can be used to generate electricity.
Describe the process of landfill monitoring?
Monitoring is carried out before, during and after
the placement of waste. Numerous monitoring wells are constructed around a landfill site (both upstream and downstream) to check for contamination. Companies are responsible for a site for 75 years after closure.
Chemical testing is carried out regularly on:
-Groundwater
- Leachate
- Landfill Gas
Describe where radioactive waste could be stored
The waste will remain highly radioactive for more than 500,000 years. This time span requires a geologically stable area— no active faults no volcanoes. Bedrock needs to be relatively impermeable, not riddled with
underground channels and sinkholes .There must be no groundwater, which would soak storage casks and mobilise radioactive materials,
possibly allowing tainted water to reach the surface.
